Coordination Chemistry Reviews, 84 (1988) 85-277
Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands
Ru(II) POLYPYRIDINE
PHOTOCHEMWT’RY,
AND CHEMILUMINE
85
COMPLEXES:
PHOTOPI3YSICS,
ELECl?ROCHEMISTRY,
SCENCE
A. JURIS and V. BALZANI
Dipartimento Chimico “G. Ciamician”, University of Bologna, and Istituto FRAE-CNR,
Bologna (Italy)
F. BARIGELLETTI
Istituto FRAE-CNR,
Bologna (Italy)
S. CAMPAGNA
Dipartimento Chimico “G. Ciamician”, University of Bologna, Bologna (IfaZy)
P. BELSER
and A. VON ZELEWSKY
Institute for Inorganic Chemistry, University of Fribourg (Switzerland)
(Received 2 February 1987)
CONTENTS
A.
Introduction _ . _ . _ _ _ . _ . _ . . . _ . _ . _ . _ _ . _ . _ . _ . . . . . _ _ _ . _ . _ _ _ _ _ . . . _ _ _
Scope and Iimitations . . . . . . _ . _ . _ . _ . . . . . . . . _ . _ _ _ . . _ . . . . . . . . . . _
(9
(ii)
PhotochemicaI and photophysical processes . . . . . _ . . _ . . _ . . . . . . . . . _ _ .
(iii)
Kinetics of energy and electron transfer processes . . . . . . _ . . _ . . . . . . . . . .
(iv)
LightasareactantandIightasaproduct
_. _ _. . . . . _. . _. __ _ _ __ _. . . _ _
(v)
Light absorption and light emission sensitizers . . . . . . _ . _ _ _ . _ . . . . . . . . _
(vi)
Structure, bonding, and excited states of Ru(II) polypyridine complexes . . . .
(vii)
Redox properties of Ru(I1) polypyridine complexes in the ground state . . . . .
(viii)
LocaIizationanddelocaIizationproblems
_ _. . . . _ _ _ _ _ _. _. _ _ _. _. . _. _.
B. Ru(bpy)z+: theprototype.
_. . . . . _. _. _ _ _ _ _ _. . . _. . . . . _. _ _ _. _. _. _. . . .
Ground state properties . . . . _ . . . . . . . _ . . . . . . . . . . . . _ . _ . _ . . . . . _ _ .
(0
(ii)
Absorptionspectrum........................................
(iii) Deactivation of upper excited states _ . _ _ _ . _ . . _ . . . . . . _ _ _ _ _ _ . _ . _ . . . .
(iv)
Emissionproperties
_._...._.__
___.___._
.___.
_._._______.._..
(v)
Photosubstitution and photoracemization processes . . . . . _ _ . . . . . . . . . . . .
(vi)
Quenching of the ‘MLCT excited state: energy and electron transfer processes
(vii) Chemical generation of the 3MLCT excited state: chemiluminescence and
electrochemihuninescence processes . . . . . . . . . . . . . . . . . . . . . . _ . . . . . . .
W9
RNvy)
: + as a Iight absorption sensitizer _ . . . . . _ . . . . _ _ . _ . . . . . . . . . .
_ _ _. _. . . . . . . . _. _ _ _. _. . . . . .
W
RWw9;
* asaIightemissionscnsitizer_
OOlO-8545/88,‘$67.20
0 1988 Elsevier Science Publishers B-V.
86
86
87
91
94
96
98
101
103
103
103
105
105
107
109
111
114
117
119
86
C. Tuning of excited state properties in the Ru(I1) polypyridine family . . _ . _ . . . . . .
Orbital nature of the lowest excited state . . _ _ . . . _ . _ . . . . . . . . _ . _ . _ . _ .
(i)
(ii)
Excitedstateenergy
_..._._......__.....
__ _...
__._.____
. . .._.
(iii) Excited state redox properties . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
D.Otherselectedtopics
. . . . .._._._.__
____ ._...
_____._
_.....
__ _._.._
Emission lifetime and its temperature dependence _ . _ . _ . . . _ . _ . _ . . . _ _ . .
(i)
(ii)
Correlations between spectroscopy and electrochemistry . _ . _ _ _ _ _ . . _ _ _ _ _
(iii) Localization and delocalization problems . . . . . . . . . . . . . . . . . . . . . . . . . .
Acknowledgments...,...............
_ _.____._._
_ ___..___._
. .._._._
E. Collection of spectroscopic, redox, photochemical, and photophysical data . _ . . _ _
Table l-Spectroscopic and photophysical data . _ . . . . _ _ . . . . _ _ . + . . _ . _ .
G)
(ii)
Table 2-Photochemical properties . . . . . . . . . . . . . . . . . . . _ . . . _ . . . _ . _ .
(iii) Table 3-Redox potentials of ground and excited states _ _ . . . . _ . _ . . . . . _ .
F. Appendix .____._......__.....__..._._...____
_.._....._.___._.
Abbreviations
for
ligands
.
.
.
.
.
.
.
.
_
.
.
.
.
.
.
.
_
.
.
.
. _. . . _. . . _. _. . . . .
0)
(ii)
Structural formulae of the ligands _ . . . . . _ . _ . . _ . _ . . . . . _ . . . _ . . _ . . . _
(iii) Otherabbreviations..
. . . .._ _ __......_
__ ._...___
_._____._.___
References ._._._.....__............_........_...................
123
124
127
128
129
129
133
138
145
145
146
192
196
244
244
253
263
264
A. INTRODUCTION
(i) Scope and limitations
Ru(bPY): + has certainly been one of the molecules most extensively
studied and most widely used in research laboratories during the last ten
years. A unique combination of chemical stability, redox properties, excited
state reactivity, luminescence emission, and excited state lifetime has attracted the attention of many research workers first on this molecule and
then on some several hundred of its derivatives. The great interest generated
by the studying of this class of complexes has stimulated the growth of
several branches of pure and applied chemistry. In particular, the Ru(I1)
polypyridine complexes have played and are still playing a key role in the
development of photochemistry, photophysics, photocatalysis, electrochemand
istry, photoelectrochemistry, chemi- and electrochemi-luminescence,
electron and energy transfer.
The aims of this review are (i) to collect data concerning the absorption
and emission spectra and the electrochemical, photochemical, and photophysical properties of the Ru(I1) polypyridine complexes in solution, and (ii)
to discuss briefly some selected topics related to the excited state properties
of these complexes. In an introductory section we have illustrated some
fundamental concepts which are needed in order to understand the scope of
the material reviewed. The literature coverage concerning the electrochemical, photochemical and photophysical data has been quite extensive and
much effort has been made to provide tables where the available data can be
easily found.
87
photochemical
reaction
products
A + h3’ luminescence
A+hS
A + heat
A and/or
radiationless
deactivation
products
quenching
processes
Fig. 1. Schematic representation of excited state deactivation processes.
(ii) Photochemical
and photophysical processes
The first act of any photochemical and photophysical process is the
absorption of a photon by a molecule. The excited state that is formed in
this way is a high energy, unstable species which must undergo some type of
deactivation. As shown in Fig. 1, excited state deactivation can occur via (i)
disappearance of the original molecule (photochemical reaction), (ii) emission of light (luminescence), (iii) degradation of the excess energy into heat
(radiationless deactivation), and (iv) some type of interaction with other
species present in the solution (quenching process).
As is well known from electronic spectroscopy [l-5], the probability of
light absorption (and thus the intensity of the correspondent absorption
band) is related to the characteristics of the states involved and particularly
to their spin quantum number. Transitions from the ground state to excited
states having the same spin value are allowed and give rise to intense bands,
whereas transitions to excited states of different spin value are forbidden
and can hardly be observed in the absorption spectra. In most molecules the
ground state is a singlet and the lowest excited state is a triplet that cannot
be directly populated by light absorption but can be obtained from the
88
A(S1)
-
A(T,)
abs
A&)--
L
1
Fig. 2. Schematic Jablonski diagram showing the various deactivation processes, k,, kit, kisc,
k
and k$ are the unimolecular rate constants for fluorescence, internal conversion,
$4
TI intersystem crossing, phosphorescence, and Tl + So intersystem crossing, respectively .
deactivation of upper excited states. For this reason, at least three states
(e.g., ground state singlet and excited singlet and triplet) are involved in a
photochemical process, as is shown in the Jablonski diagram of Fig. 2.
Emission of light (luminescence) is called fluorescence or phosphorescence
depending on whether the excited state has the same or different spin
compared to the ground state. In the same way, radiationless deactivation is
called internal conversion when it occurs between states of the same spin
and intersystem crossing when it occurs between states of different spin.
Fluorescence and internal conversion are spin-allowed steps, whereas phosphorescence and intersystem crossing are spin-forbidden steps. Each intramolecular decay step is characterized by its own rate constant (Fig. 2) and
each excited state is characterized by its lifetime, given by
i
where ki is the first order rate constant for a generic unimolecular process
that causes the disappearance of the excited state [3,4,6,7]. For each process
one can define the quantum yield, which is the ratio between the number of
moles of species (photons or molecules) produced and the number of
89
A fB
energy
C +0
cheinical
transfer
encounter
complex
*A+B=
I
Ebl
k diff
..B _
k-ditf
A or products
A + B catalyzed
reaction
deactivation
Fig. 3. Schematic representation of bimolecular processes that may take place following an
encounter between an excited state and another chemical species.
einsteins that have been absorbed. A particularly important quantity is the
quantum yield of emission from the lowest spin-forbidden excited state
(phosphorescence quantum yield, aP) which, making reference to Fig. 2, can
be expressed by the following equation
@‘p = rlisc
kprTl
0)
In this equation, rli, is the efficiency of population of the emitting excited
state from the state populated by light absorption:
=
rli.92
kisc/t
ki.5c
+
kf
+
kit)
(3)
and rr1 is the lifetime of the emitting excited state
7T,
=
l/(k, + ki’,,)
(4
When the intramolecular deactivation steps are not too fast, i.e. when the
lifetime of the excited state (eqn. 1) is sufficiently long, the excited molecule
may have a chance to encounter a molecule of another solute, B (Fig. I). In
such a case, some specific interaction may occur (Fig. 3) and the process
taking place is called a bimolecular process [6-91. Simple kinetic arguments
show that only those excited states that live longer than - 10m9 s may have
a chance to be involved in encounters with other solute molecules. For
transition metal complexes, only the lowest spin-forbidden excited state
satisfies this requirement.
The most important bimolecular processes are energy transfer [4,7,9,10]
and electron transfer [4,7-9,111;
the latter process may involve either the
oxidation or the reduction of the excited state
*A+B%A+*B
energy transfer
(5)
90
*A + B&A+
*A+B-
k+A-
+ B-
oxidative electron transfer
(6)
+ B+
reductive electron transfer
(7)
The ability of an excited state to intervene in energy transfer processes is
related to its zero-zero spectroscopic energy, E*-‘. For the electron transfer
processes, the relevant thermodynamic parameters are the oxidation (eqn. 6)
and *A/Acouples.
and reduction (eqn. 7) potentials of the *A/A+
Because of its higher energy content, an excited state is both a stronger
reductant and a stronger oxidant than the corresponding ground state. To a
first approximation, the redox potentials for the excited state couples may
be calculated from the potentials of the ground state couples and the
zero-zero excitation energy Eoeo:
E(A+,‘*A)
= E(A+,‘A)
-E”-’
E(*A/A-)
= E(A,‘A-)
+ E"-'
(8)
(9)
Figure 4 shows schematically some quantities that characterize an excited
state from the point of view of energy and electron transfer processes_
Kinetic parameters (i.e., intrinsic barrier and electronic transmission coefficient) can also play an important role in energy and electron transfer
processes, as is discussed in detail in the next Section.
u+
A
Fig. 4. Schematic diagram showing the molecular quantities relevant for energy and electron
transfer processes.
91
(iii) Kinetics of energy and electron transfer processes
Ru(II) polypyridine complexes are extensively used in energy and electron
transfer processes [8,9,11-161. An important aim of these studies is the
elucidation of the factors that govern the reaction rates.
Outer-sphere electron transfer (regardless of the ground or excited state
nature of the reactants) [8,9,17-201 and exchange energy transfer [9,10] are
closely related processes that can be dealt with by the same formalism 1211.
Using an excited state electron transfer reaction as an example [18]
*D + A+D+
+ A-
00)
the reaction rate can be discussed on the basis of the mechanism shown in
the scheme of Fig. 5, where k,, k_,, ki, and k:, are rate constants for
formation and dissociation of the outer-sphere encounter complex, k, and
k_, are unimolecular rate constants for the electron transfer step involving
the excited state, and k,(g) and k_,(g)
are the corresponding rate constants
for the ground state electron transfer step. A simple steady state treatment
shows that the experimental rate constant of eqn. (10) can be expressed as a
function of the rate constants of the various steps
k exp
=
kc3
k-d + k-,
I-rk
k-,
k,k,
e
where k, may often be replaced by k’, (for more details, see ref. 18). Using
a classical approach, k_ Jk, is given by exp( AG/RT),
where AG is the free
energy change of the electron transfer step. The key step of the process is, of
course, the electron transfer step and the essence of the problem is the fact
that the equilibrium nuclear configuration of a species changes when it gains
or loses an electron (or electronic energy) [19]. For transition metal complexes in fluid solution this configuration change may involve changes in
metal-ligand bond and intraligand bond lengths and angles and, at least in
k:d
k’d
D +A
=D...<
k-d
D+ + A- _ kp
products
A
Fig. 5. Detailed mechanism for an electron transfer process involving an excited state reactant
(see text).
92
1
nuclear
configuration
Fig. 6. Representation of an outer-sphere electron transfer process using energy curves:
curves i and f correspond to the precursor (D * - * - A) and successor (D+ - - - A- ) complexes
of Fig. 5. For more details, see text.
the case of electron transfer, changes in the vibrations and rotations of
solvent dipoles. Since electronic motions are much faster than nuclear
motions (Franck-Condon principle), in a classical approach an adjustment
of the nuclear configuration prior to electron (or energy) transfer is required.
This gives rise to an activation barrier, AG # , as shown in Fig. 6. Once a
suitable nuclear configuration has been reached, whether or not electron (or
energy) transfer occurs is a matter of electronic factors (adiabaticity problem
~19,221).
Using a classical approach, the rate constant of electron transfer can be
given by
k, = tcvn
exp( - AG #,/RT)
(12)
where K is the electronic transmission coefficient, vn is an effective frequency
for nuclear motion, and AG # is the free activation energy, which may be
expressed by a free energy relationship like the classical Marcus quadratic
equation [19,23]
AG+ = AG+(O){l
+ [AG/4AG+(O)]
)’
(13)
or empirical equations like [l&24,25]
AG+=AG+
AG + (0)
In 2
AG In 2
AG + (0) il
(14)
where AG # (0) is the so-called intrinsic nuclear barrier (Fig. 6). For a
homogeneous series of reactions [l&26,27], such as those between the same
reductant *D and a series of structurally related oxidants A,, A,, A,. _ _ (or
vice versa) that have variable redox potential but the same size, shape,
electronic structure and electric charge, one can assume that throughout the
series the reaction parameters k,, k_ d, k L d in eqn. (ll), K and V~ in eqn.
93
0
AG
vs. AG plots for a homogeneous series of outer-sphere electron
Fig. 7. Expected log k,
transfer reactions, according to eqns. (ll), (12), and (14). (a) Effect of the intrinsic barrier
AG # (0); (b) effect of the transmission coefficient K.
(12) and AG ‘(0) in eqn. (14) are constant. Under these assumptions, k,,
(eqn. 11) is only a function of AG and a log k,, vs.AG plot will exhibit the
following features (Fig. 7): (i) an Arrhenius type linear region for sufficiently
endergonic reactions; (ii) a more or less wide intermediate region (depending
on AG + (0)) in which log k,, increases in a complex but monotonic way as
AG decreases, and (iii) a plateau region for sufficiently exergonic reactions
when the free energy correlation given by eqn. (14) is used (use of eqn.. 13
would predict a decrease of the reaction rate at high exergonicity usually not
observed for reactions in fluid solution at room temperature [7,18,28-331).
As shown in Fig. 7, the values of the intrinsic barrier AG+(O) strongly
influence the values of the rate constant in the intermediate non-linear
region, while a lower than diffusion controlled value of the plateau at high
exergonicity is related to a low value of the transmission coefficient K
(non-adiabatic behavior). These free energy relationships are extensively
used to establish whether a series of quenching reactions take place via
energy transfer, reductive electron transfer, or oxidative electron transfer
(Section B (vi)). Furthermore, when the values of the other parameters are
known, a two-parameter fit of the log k,,, vs. AG plot to eqns. (111, (12),
and (14) may allow, in principle, estimation of the values of AG # (0) and K
of the homogeneous series of reactions. When either AG # (0) or K is known
from other experimental results (or can be estimated from reasonable
assumptions), a more reliable one-parameter fit can be used to estimate the
unknown quantity. The model can also be further elaborated [l&22,27,34-37]
in an attempt to obtain parameters related to the individual reactants.
94
(iv) Light us a reactant and right us a product
The class of chemical reactions that plays the most important role in the
connection between chemistry and light is that of electron transfer reactions.
Ru(I1) polypyridine complexes have given a determinant contribution to the
recent development of this class of reactions.
When light is used as a reactant (photochemical reaction, eqns. (15) and
t 1%
A+hv+*A
(15)
(16)
*A+B-,A++B-
there are two possible energetic situations for electron transfer reactions,
schematically represented in Fig. 8. The scheme of Fig. S(a) corresponds to
an exergonic dark reaction which is slow for kinetic reasons (high activation
energy). Upon light excitation, the reductant A is transformed into the much
stronger reductant *A (vide supra), so that the reaction between *A and B is
much more exergonic that the reaction between A and B. Since the activation energy generally decreases with increasing exergonicity, the reaction
involving the excited state will be much faster than that involving the
ground state. In a system of this kind light is simply used to overcome a
kinetic barrier and plays the role of a catalyst. The scheme shown in Fig.
8(b) corresponds to the case of a A + B -+ A+ + B - dark reaction that
cannot take place because of thermodynamic reasons. Light excitation
causes the formation of *A which is a reductant much stronger than A, so
that the reaction *A + B -+ A+ + B- is thermodynamically allowed. Light
a
Fig. 8. Schematic representation of the two possible energetic situations for electron transfer
reactions involving an excited state reactant. For details see text.
95
bt+ B*A+6
A+B
Fig. 9. Schematic representation of the energetic situation needed for generation of an excited
state from an electron transfer reaction.
can thus drive A + B to A+ + B- via *A + B, and in such a process a
fraction of the light energy is converted into chemical energy of the
products. The converted energy is released when A+ and B- undergo the
back electron transfer reaction leading to A + B.
In electron transfer reactions, light can also be involved as a product
(chemiluminescent reactions):
A++B-
+*A+B
*A-,A+hv
(171
(18)
This process can be schematically represented as in Fig. 9, which differs
from those shown in Fig. 8 because the energy content of A+ + B - is not
only higher than that of A + B, but also than that of *A + B. In such a case
the reaction from A + B to A+ + B- can be driven neither thermally nor
photochemically. When A+ and B- can be prepared in some other way (e.g.,
electrochemically) and are mixed together, their electron transfer reaction
can lead either to A + B, with complete dissipation of the excess free energy
into heat, or to ‘A + B, with dissipation of a smaller amount of energy. In
the latter case, *A can undergo radiative deactivation (luminescence) so that
in this reaction a fraction of the available chemical energy is converted into
light energy.
From this discussion it is clear that a chemiluminescent process can be
considered as the reverse of a photochemical process
photochemistry
A+B+hv**A+BzSA++Bchemiluminescence
09)
and that the equilibrium represented by eqn. (19) is displaced from left to
right or from right to left depending on whether the energetic situation is
that depicted in Fig. 8 or in Fig. 9. The availability of a class of compounds
(such as those of the Ru(I1) polypyridine family) which cover a wide range
of redox potentials and excited state energies (Tables 1 and 3) is of course
fundamental to the investigation of these processes.
96
(v) Light absorption and light emission sensitizers
Ru(I1) polypyridine compounds are extensively used not only as primary
reactants in electron transfer processes involving light (Section A (iv)), but
also as mediators of potential photochemical and chemiluminescent processes
[38,39].
There are “potential” photochemical reactions that do not occur because
the reactants are not able to absorb light and/or because their excited states
are too short lived. Consider, for example, a chemical reaction
A+B++A++B-
(20)
that cannot occur in the dark because it is endoergonic by, say, 1 eV. In
principle, excitation with visible light would made the process thermodynamically allowed (Fig. 8(b)). However, if neither A nor B are able to absorb
the exciting light, the reaction cannot occur
A+B+hv-+A++B-
(21)
This “potential” photochemical reaction can be induced (or sensitized) by a
species which possesses specific redox, spectroscopic, and excited state
properties. Such species can be called light absorption sensitizers (LAS) [38]
and must perform as shown schematically in Fig. 10: (i) it must absorb light
so as to give an excited state; (ii) this excited state must be able to oxidize
(or reduce) one of the reactants of eqn. (21); (iii) the reduced (or oxidized)
form of the photosensitizer must be able to reduce (or oxidize) the other
reactant in order to complete the redox process indicated by eqn, (21) and to
Fig. 10. Schematic representation of a photosensitized electron transfer reaction. LAS = light
absorption sensitizer.
97
regenerate the LAS. Looking at the schemes of Figs. 4 and 10, it is possible
to make the following list of requirements for an ideal LAS [40,41]: (1)
reversible redox behavior; (2) suitable ground and excited state potentials;
(3) stability towards thermal and photochemical decomposition; (4) intense
absorption in a suitable spectral region; (5) small energy gap between
relevant excited states; (6) high efficiency of population of the reactive
excited state; (7) suitable lifetime of the reactive excited state; (8) high
energy content of the reactive excited state; (9) good kinetic factors for outer
sphere electron transfer reactions. LAS can carry on a variety of useful
processes [38]. Their development will hopefully make possible the conversion of simple molecules like H,O and CO, (which do not absorb solar
energy) into fuels (HZ, CH,) by means of non-biological photosynthetic
processes [42-451.
“ Potential” chemiluminescent reactions are reactions sufficiently exergonic to generate light but producing only heat because no excited state
(or, better, no emitting excited state) is formed
A++B-++A+B+hv
(22)
In the same way as “potential” photochemical reactions can be induced by
LAS, “potential” chemiluminescent reactions can be induced by suitable
species that can be called light emission sensitizers (LES) [38]. As shown in
Fig. 11, a LES must perform in the following way: (i) it must be oxidized (or
reduced) by one of the reactants of eqn. (22); (ii) its oxidized (or reduced)
form so obtained must then oxidize (or reduce) the other reactant to yield an
excited state, *LES; (iii) such an excited state must undergo radiative
deactivation (luminescence), regenerating the ground state LES. In this way,
I
lLEs
lLES
LES
-T
h3
A++ B--A.
B+
hJ
h3
Fig. 11. Schematic representation of a sensitized chemiluminescent electron transfer reaction.
LES = light emission sensitizer.
98
part of the exergonicity of the electron transfer reaction between A+ and Bis channelled to light generation. LES are less known than LAS, but they are
presently the object of much research because they may have several
applications (e.g., in the field of display devices [46, 471). From the schemes
shown in Figs. 4 and 11, the requirements for an ideal LES must be as
follows [40]: (1) reversible redox behavior; (2) suitable ground and excited
state potentials; (3) stability towards thermal and photochemical decomposition reactions; (4) suitable excited state energy; (5) strong luminescence
emission (high efficiency for the radiative deactivation of the excited state);
(6) good kinetic factors for outer sphere electron transfer reactions_
As can be seen from the above lists, the stability and redox requirements
are the same for LAS and LES. From a spectroscopic point of view, the
requirements are somewhat different (e.g., a LES does not need to have
intense absorption bands and a LAS does not need to exhibit luminescence),
but slow radiationless deactivation of the excited state is a fundamental
requirement in both cases because a LAS must have a long excited state
lifetime and a LES must have a high emission efficiency. Thus, it is not
surprising that a compound which can play a role of LAS can also play a
role of LES. Ru(I1) polypyridine complexes, because of their redox and
excited state properties, satisfy most of the requirements needed for LAS
and LES.
(vi) Structure, bonding, and excited states of Ru(I1) polypyridine complexes
Ru*” is a d6 system and the polypyridine ligands are usually colorless
molecules possessing a-donor orbitals localized on the nitrogen atoms and VT
donor and V* acceptor orbitals more or less delocalized on aromatic rings.
Following a single-configuration one-electron description of the excited state
in octahedral symmetry (Fig. 12(a)), promotion of an electron from a 7rTM
metal orbital to the 7~: ligand orbitals gives rise to metal-to-ligand charge
transfer (MLCT) excited states, whereas promotion of an electron from 7rM
to 0c orbitals gives rise to metal centered (MC) excited states. Ligand
centered (LC) excited states can be obtained by promoting an electron from
7rL to 77;. All these excited states may have singlet or triplet multiplicity,
although spin-orbit coupling causes singlet-triplet mixing in the MC and
MLCT excited states [48-511. Actually Ru(bpy)$‘,
as well as the other
Ru(LL);+
complexes (LL = bidentate polypyridine ligand), exhibits a D3
symmetry (Fig. 13) [52]. Following Orgel’s notation [53], the m * orbitals may
be symmetrical (x) or antisymmetrical (JI) with respect to rotation around
the C, axis retained by each Ru(bpy) unit. A more detailed picture of the
highest occupied and lowest empty orbital is shown in Fig. 12(b) [14,15,54].
The highest filled molecular orbitals are TMal( d) and vMe( d), which are
99
1
filled
orbitals
Fig. 12. (a). Simplified molecular orbital diagram for Ru(LL)z+
complexes in octahedral
symmetry showing the three types of electronic transitions occurring at low energies; (b)
detailed representation of the MLCT transition in D3 symmetry.
predominantly localized on the metal; the lowest empty molecular orbitals
are rEa2( +) and rrrEe(+), which are predominantly localized on the ligands.
The ground state of the complex is a singlet, derived from the
TMe ( d )"TT~
q( d) *electronic configuration.
The high energy excited states of transition metal complexes undergo fast
radiationless deactivation [55]. Thus, only the lowest excited state and the
upper states that can be populated on the basis of the Boltzmann equi-
Tig. 13. Structure of Ru(bpy)g+
[52].
loo
w
‘M-L
‘M-L
Fig. 14. Schematic representation of two limiting cases for the relative positions of ‘MC
3LC (or 3MLCT) excited states.
and
librium law may play a role in the luminescence emission and in bimolecular
processes.
The MC excited states of d6 octahedral complexes are strongly displaced
with respect to the ground state geometry along metal-ligand
vibration
coordinates [2,56]. When the lowest excited state is MC, it undergoes fast
radiationless deactivation to the ground state and/or
ligand dissociation
reactions (Fig. 14(b)). As a consequence, at room temperature the excited
state lifetime is very short, no luminescence emission can be observed [57]
and no bimolecular reaction can take place. LC and MLCT excited states
are usually not strongly displaced compared to the ground state geometry.
Thus, when the lowest excited state is LC or MLCT (Fig. 14(a)) it does not
undergo fast radiationless decay to the ground state and luminescence can
usually be observed, except at high temperature when thermally activated
radiationless deactivation via upper lying MC excited states can occur. The
radiative deactivation rate constant is somewhat higher for 3MLCT than for
3LC because of the larger spin-orbit coupling effect. For this reason, the
3LC excited states are longer lived at low temperature in rigid matrix and
the 3MLCT excited states are more likely to exhibit luminescence at room
temperature in fluid solution where the lifetime of 3LC and 3MLCT is
shortened by activated surface crossing to short lived MC excited states or
by bimolecular quenching processes.
From this discussion it is clear that the luminescent properties of a
complex as well as its ability to play the role of excited state reactant, (eqn.
16), excited state product (eqn. (17)), LAS (Fig. lo), or LES (Fig. 11) are
101
related to the energy ordering of its low energy excited states and, particularly, to the orbital nature of its lowest excited state. The energy positions of
the MC, MLCT, and LC excited states depend on the ligand field strength,
the redox properties of metal and ligands, and intrinsic properties of the
ligands, respectively [2]. Thus, in a series of complexes of the same metal ion
the energy ordering of the various excited states, and particularly the orbital
nature of the lowest excited state, can be controlled by a judicious choice of
the ligands [40,48,58]. In this way, it is possible to design complexes having,
at least to a certain degree, the desired properties (Section C). For most
Ru(X1) polypyridine complexes, the lowest excited state is a 3MLCT which
undergoes relatively slow radiationless transitions and thus exhibits long
lifetime and intense luminescence emission.
(vii)
Redox properties
of Ru(ll)
polypyridine
compiexes
in the ground state
As mentioned above, the complexes of the Ru(II) polypyridine family are
particularly interesting as excited state reactants or products in electron
transfer processes and as mediators (LAS or LES) of electron transfer
reactions involving light. A fundamental requirement for playing these roles
is the stability of the oxidized and/or reduced forms, i.e. the reversibility of
the oxidation and/or reduction processes in the ground state. A wealth of
information is available on the electrochemical behavior of ruthenium-polypyridine complexes. The most widely used electrochemical method has been
cyclic voltammetry (CV) in non-aqueous aprotic solvents. Following the
pioneering work on Ru(bpy) z + [59], many measurements on similar complexes were performed (Table 3). The feature of CVs of many complexes of
the Ru(II)-polypyridine
family is the possibility of localizing with a high
degree of certainty the donor or the acceptor orbital of the one electron
transfer reaction_
Oxidation of Ru(II) polypyridine complexes usually involves a metal
centered (parent 7rTM(
t,,) in octahedral symmetry) orbital, with formation of
genuine Ru(II1) complexes (low spin 4d5 configuration) which are inert to
ligand substitution [59]
[Ru’+(LL)~]~+~
[Ru3+(LL),13++
e-
(23)
Normally, only a one-electron oxidation is obtained in the potential range
available. It is not always feasible to compare potentials reported in the
literature on an absolute scale. It can be stated, however, that the Ru(II)/
Ru(III) potentials in the complexes where the ligands are exclusively true
polypyridine molecules, fall in a rather narrow range around + 1.25 V with
respect to NHE. Substitution of one or more polypyridine ligands by
another base can drastically change these potentials. The substitution of one
102
bpy in Ru(bpy) 5’ with two Cl- ions to give Ru(bpy) &12 lowers the
potential to about +0.35 V, whereas the strong ?r*-acceptor CO causes an
increase above + 1.9 V in Ru(bpy),(CO)z+
(Table 3).
Reduction of Ru(II) polypyridine complexes may in principle involve
either a metal-centered or a ligand-centered orbital, depending on the
relative energy ordering. When the ligand field is sufficiently strong and/or
the ligands can be easily reduced, reduction takes place on a ligand 7~c
orbital. This is the commonly observed behavior of Ru(II)-polypyridine
complexes [60,61,65] (Table 3). The reduced form, keeping its low-spin 4d6
configuration, is usually quite inert and the reduction process is reversible:
As discussed in Sections A (viii) and D (iii), the added electron appears to
be localized on a single ligand. Several reduction steps can often be observed
in the potential range accessible. This range has been considerably enlarged
through the measurement of CV at low temperature [62,63]. Up to six
electrons can be pumped into Ru(bpy) i’ in this way [62], yielding a highly
reduced complex which can be formulated as [R~~+(bpy~-)~]~-.
The localization of the acceptor orbitals in the reduction processes is often particularly
clear in mixed hgand complexes involving polypyridine ligands with different energies of the 7 * orbitals. In such cases, the first and subsequent
reduction steps can be attributed to the various Iigands in the complex.
When the ligand field is weak and/or
the ligands cannot be easily
reduced, the lowest empty orbital in the reduction process could be metal
centered (parent ~r&(eg) in octahedral symmetry). In such a case, reduction
would lead to an unstable low spin d7 system, which should give rise to a
fast ligand dissociation making the process electrochemically irreversible
[Ru~+(LL)~]~+
+ e--,
[Ru+(LL),]+-,
[Ru+(LL)J++LL
(25)
Such behavior has been reported for iridium complexes 1641, but has never
been clearly observed in the case of ruthenium.
It is important to note that, if the Koopmans theorem is valid for the
startmg rgg system and for the one-electron reduced species, the 7~: or CJ&
orbitals that can be involved in the reduction processes (redox orbitals) are
the same orbitals which are involved in the MLCT and MC transition,
respectively (spectroscopic orbitals). Thus, reversibility of the first reduction
step, indicating a ligand centered LUMO, also implies (to a first approximation) that the lowest excited state is MLCT. More generally, there are
correlations between the electrochemical and spectroscopic data, as will be
discussed in Section D (ii).
103
a
b
Fig. 15. Pictorial description of the electron promoted to the rnc orbital: (a) multichelate ring
delocalized orbital; (b) single chelate ring localized orbital [65].
(viii) Localization
and delocalization problems
For most complexes of the Ru(II) polypyridine family the excited state
responsible for luminescence emission and bimolecular excited state reactions is a 3MLCT (or a cluster [48] of closely spaced 3MLCT levels), i.e. a
state obtained prOmOting
a metal TM orbital to a ligand 7~: orbital (Fig. 12).
As mentioned before, the same ~2 orbital is involved in the one-electron
reduction process. Even if we leave aside a detailed spin and symmetry
description of the 3MLCT state, the problem arises whether the spectroscopic and redox orbital is best described as a multichelate ring delocalized
orbital (Fig. 15(a)) or a single chelate ring localized orbital with a small
amount of interligand interaction (Fig. 15(b)) [65]. This problem has been
tackled with a variety of techniques both on reduced and excited complexes.
Compelling evidence for “spatially isolated” [66] redox orbitals has been
obtained from low temperature cyclic voltammetry 162,631, electron spin
resonance [67-691, electronic absorption spectra [70-721, nuclear magnetic
resonance [73], and resonance Raman spectra [74]. A more detailed discussion of the localization problem will be given in Section D (iii)_
B. Ru(bpy) f + : THE PROTOTYPE
(i) Ground state properties
The ground state structure of Ru(bpy): ) in its hexafluorophosphate salt
has been determined by X-ray crystallography [52]. The complex possesses
O3 symmetry (Fig. 13) and the Ru-N bond length of 205.6 pm is somewhat
shorter than the 210.4 pm value in Ru(NH,)z+
[75], indicating a significant
backbonding between Ru(I1) and the V* orbitals of bpy. A five line 13C
104
I,
I
+0.8
I
I
0
I
I1
-0.8
I
-1.8
I
V
Fig. 16. Cyclic voltammogram of Ru(bpy)g+
in acetonitrile.
NMR spectrum is observed for the solvated ‘species
[54] and the ‘H NMR
spectrum [76] can be interpreted in terms of four coupled spins in each six
equivalent pyridine rings. The solution NMR data are therefore consistent
with retention of O3 symmetry for the solvated species. Resolution of the
enantiomers can be achieved [77], and these are found to be thermally stable
with respect to racemization [78].
The Ru(bpy) f ’ cation shows remarkable chemical stability. For example
it can be stored in aqueous solutions for months [79] and is reported to be
unaffected by boiling concentrated HCl or 50% aqueous sodium hydroxide
solutions [SO].
The cyclic voltammograrn of Ru(bpy)g+ in AN (potentials vs. Ag electrode) is shown in Fig. 16. One oxidation and three reduction processes, all
monoelectronic and reversible, can be observed. The redox potentials are
independent of solvent (for AN, DMSO, DMF, and propylene carbonate)
[81]. The oxidized form, Ru(bpy)s+, can be easily obtained by chemical
oxidation of Ru(bpy) $’ with nitric acid [80], dichlorine ]82] or lead dioxide
[83]. The absorption spectrum of Ru(bpy)i+ shows a weak band at - 420
nm (Glax = 3.3 x lo3 M-l cm-‘) and a broad and weak absorption at longer
wavelengths [14]. Ru(bpy):+ is reduced by water, but the reaction mechanism is very complicated and governed by the pH of the solution and the
presence of catalysts, even at impurity levels [84-901. Under most experimental conditions the amount of 0, generated is much less than that
expected on the basis of a simple reduction of Ru(bpy);+ to Ru(bpy):+
. The
and
reduction of aqueous Ru(bpy), 2+ by pulse radiolysis via the CH,O(CH3)2COradicals at pH 11-13 yields Ru(bpy)z 1911 which can also be
prepared by extensive electrolysis of Ru(bpy):+
in non-aqueous solvents
[71,72,92,93]. The absorption spectrum of Ru(bpy)g shows a broad and
intense ( E _ - lo* M-l cm-‘) band in the visible with maximum at - 510
nm. Compelling evidence for reduction taking place on a single chelate ring
localized orbital (spatially isolated orbital, Sections A (viii) and D (iii)) has
been obtained, so that the reduced form is best described as a Ru(I1)
complex containing a coordinated bpy- ligand radical, [R~~+(bpy)~(bpy-)I+_
105
Wbw)
[91,94].
;
does not reduce water under neutral or alkaline
conditions
(ii) Absorption spectrum
The absorption spectrum of Ru(bpy) 5’ is shown in Fig. 17 along with the
proposed assignments [E&14,15,48,54,95]. The bands at 185 nm (not shown in
the Figure) and 285 nm have been assigned to LC VT+ 7r* transitions by
comparison with the spectrum of protonated bipyridine [96]. The two
remaining intense bands at 240 and 450 nm have been assigned to MLCT
d-*n*
transitions. The shoulders at 322 and 344 nm might be MC
transitions. In the long wavelength tail of the absorption spectrum a shoulder
is present at about 550 nm (c - 600) when the absorption measurement is
made on Ru(bpy)z+
in an ethanol-methanol
glass at 77 K [973. This
absorption feature is thought to correspond to the lowest ‘MLCT
excited
state(s).
In spite of the presence of the heavy Ru atom, it has been established that
it is reasonable to assign the electronic transitions of Ru(bpy)$+ as being to
“ singlet” or “ triplet” states. In particular, a singlet character 4 10% has
been estimated [50] for the lower-lying excited states of Ru(bpy)z+
. The
maximum of the ‘MLCT band at - 450 mn is slightly sensitive to solvent,
suggesting an instantaneous sensing of the formation of the dipolar excited
state [R~~*(bpy)~(bpy-)]~+
[98] (see Section D (iii)).
(iii) Deactivation of upper excited states
As mentioned in the introduction (Section A (ii)) the upper excited states
of transition metal complexes undergo either chemical reaction or radiation-
5
0
0”
4
3
21 D
1
I
300
400
500
6
0
A fnm)
Fig. 17. Electronic absorption spectrum of Ru(bpy) :’
.
106
01
300
I
I
400
500
A, nm
Fig. 18. Electronic absorption spectrum of the lowest excited state of Ru(bpy)z+
[loll.
less deactivation to the lowest excited state. For Ru(bpy):+
the lowest
excited state (or, better, the cluster of lowest excited states) is relatively long
lived and its formation and disappearance can be easily monitored by flash
spectroscopy and luminescence decay. The absorption spectrum of the
lowest excited state is shown in Fig. 18 [99-1011. The risetime of the lowest
excited state upon excitation of spin allowed excited states was estimated to
be +K 1 ns for Ru(bpy)i+
[102,103], indicating that the conversion of the
upper excited states to the lowest one is indeed very fast. The quantum yield
of formation of the lowest excited state Q[)3,,cr (and thus, the efficiency of
intersystem crossing from the upper singlets obtained by excitation to the
lowest triplet, rise) is essentially unity [99,104-1061. Interestingly, Q)3MLcT
has
also been evaluated by a photochemical technique, based on the ability of
( 3CT)Ru(bpy) ; + to function as a reductant (Section B (vi)) [106]. This
method, which may be useful also for other complexes, works in the
following way. The reaction of ( 3CT)Ru(bpy)z+
with S20iyields
SOiand
the
strongly
oxidizing
SO;
radical.
Once
formed,
Ru(bpy); + 7
this radical reacts with ground state Ru(bpy)z+ to yield a second Ru(bpy);+
complex ion. Experimentally, the quantum yield for disappearance of
was followed by monitoring the 450 nm absorption
Ru(bpy):+,
Q-Ruz+t,
band of Ru(bpy)i+,
and the measurements were made as a function of
[S,Ol-1. From a plot of l/Q_ RU2+versus l/[S,O,2-],
the limiting value of
concentration was found to be 2.0 + 0.2. This
Q,-_i@+ for infinite S&$value can only occur if all the Ru(bpy)z+ excited states which are formed
107
b
600
h,nm
700
Fig. 19. Emission spectrum of * R 4 bw):+ in alcoholic solution: (a) at 77 K; (b) at room
temperature.
upon light absorption react to yield Ru(bpy) :’
and SO;,
and all of the
SO; goes on to react with Ru(bpy)z+ to form a stoichiometric amount of
Ru(bpy) ; + (iv) Emission properties
Excitation of Ru(bpy) z + in any of its absorption bands leads to a
luminescence emission (Fig. 19) whose intensity, lifetime, and energy position are more or less temperature dependent. Detailed studies on the
temperature dependence [48,107-1111
of the luminescence lifetime and
quantum yield in the temperature range 2-70 K showed that luminescence
originates from a set of three closely spaced levels (A E 10 and 61 cm-‘) in
thermal equilibrium. The theoretical description of the luminescent levels
continues to be a matter of debate. There is no doubt about their MLCT
nature, whereas different opinions exist on whether these levels can be
described by a spin quantum number and whether the promoted electron
resides in a single bpy ligand or in a delocalized 7~* orbital. Recent results
suggest that the best description is that which assumes a substantial triplet
character and a single ligand localized excitation (Section D (iii)). This
cluster of luminescent, closely spaced excited states will be indicated in the
following by * Ru(bpy) 5’.
In rigid alcoholic glass at 77 K the emission lifetime of *Ru(bpy)s+
is
- 5 ps and the emission quantum yield is - 0.4 (Table 1). Taken together
with the unitary intersystem crossing efficiency, these figures yield (see eqn.
108
1
ll+
1
1
1
6
lOOO/T,K
-1 ‘0
Fig. 20. Temperature dependence of the emission lifetime of * Ru(bpy)$+
in nitrile solution
[131.
2) a value of - 13 ps for the radiative lifetime. Values of this order of
magnitude have been found for M-LCT excited states of other transition
metal complexes [112-1141. Ligand centered excited states exhibit radiative
lifetimes in the ms range [ill-113,115--1181.
With increasing temperature, the emission lifetime (Fig. 20) and quantum
yield decrease [48,95,96,119-1371.
This behavior may be accounted for (see
Section D (i)) by a stepwise term and two Arrhenius terms:
B
l’T=
k” + 1-t exp[C(l/T-
A
l/T,)]
+
1
e-A-WRT
+
A
2
e-AWRT
(26)
The value of the various parameters are somewhat dependent on the nature
of the solvent. In propionitrile-butyronitrile (4 : 5 v/v)
the values are as
follows [131,132]: k, = 2 x 10’ s-l; B = 2.1 x lo5 s-i; A, = 5.6 x lo5 s-i;
AE, = 90 cm-‘;
A, = 1.3 X lOI s-l;AE, = 3960 cm-‘. Included in k, are
the radiative k; and nonradiative k," rate constants at 84 K. The stepwise
term B is due to the melting of the matrix (100-150
K) and is thought to
correspond to the coming into play of vibrations capable of facilitating
radiationless deactivation [132]. In the same temperature interval a red shift
of - 1000 cm-l is observed in the maximum of the emission band [132].
The Arrhenius term with A, = 5.6 X lo5 s-l and AE, = 90 cm-’ is thought
to correspond to the thermal equilibration with a level lying at slightly
109
higher energy and having the same electronic nature. The second Arrhenius
term is thought to correspond to a thermally activated surface crossing to an
upper-lying 3MC level which undergoes fast deactivation (Section D (i)).
Identification of this higher level as a 3MC state is based upon the observed
photosubstitution behavior at elevated temperatures [119], consistent with
established photoreactivity patterns for d6 metal complexes [2]. Experiments
carried out with Ru(bpy)z+
and Ru(bpy-ds) f + in H,O
and D,O
[119,130,138] indicate that k,” is sensitive to deuteration, as expected for a
weak-coupled radiationless process [139-1421. By contrast, A, is insensitive
to deuteration, suggesting a strong-coupled (surface crossing) deactivation
pathway, which may be related to the observed photosensitivity. It should be
noted that the decrease in lifetime on melting has also been explained on the
basis of the energy gap law because of the correspondent red shift in the
emission band [142].
(v) Photosubstitution
and photoracemization
processes
Although Ru( bpy) ; + is normally considered as photochemically inert
towards ligand substitution, there is increasing evidence that this is not so
[14,15,142]. In aqueous solution the quantum yield of Ru(bpy);+
disappearance is in the range 1O-5-1O- 3, depending on the pH of the solution
and temperature. The exact nature of the reaction products has not been
elucidated [119,124]. In chlorinated solvents such as CH,Cl,
the photochemistry of [Ru(bpy),]X,
(X = Cl-, Br-, NCS-)
is well behaved [124,143],
giving rise to Ru(bpy) 2 X, as final product. The quantum yields are in the
range 10-1-10-2.
The PF6- salt is photoinert. A substantial difference
between aqueous and CH,Cl,
solutions is that salts of Ru(bpy)$+
are
completely ion-paired in the latter medium.
A detailed mechanism for the ligand photosubstitution reaction for
Ru(bpy):+ has been proposed [124] (Fig. 21). According to this mechanism,
thermally activated formation of a 3MC excited state (vide supra) leads to
the cleavage of a Ru-N bond, with formation of a five-coordinate square
pyramidal species. In the absence of coordinating ions, as with the PF6- salt,
this square pyramidal species returns to Ru(bpy) $’ _ When coordinating
anions are present, as in the Cl- salt, a hexacoordinated monodentate bpy
intermediate is formed. Once formed, this monodentate bpy species can
undergo loss of bpy and formation of Ru(bpy) *X2, or a “self-annealing”
process (chelate ring closure), with reformation of Ru(bpy);+ . The “self-annealing” protective step is favored in aqueous solution, presumably because
of stabilization of the cationic Ru(bpy)z+
speci?s, whereas formation of
neutral Ru(bpy),X,
complexes is favored in low polarity solvents. Photoracemization of Ru(bpy) 2 + [144] also occurs with low quantum yield (2.9 x
110
--_
4?
I
X-
,I
//
---
I’
_
,’
+x-
-by
ground
state
Fig. 21. Schematic representation of the proposed mechanism of kigand photosubstitution
reactions of Ru(bpy):+
[124].
lop4 in water at 25 OC). This process can be accounted for by a rearrangement of the square pyramidal primary photoproduct (Fig. 21) into a trigonal
bipyramidal intermediate which can lead back to either the A or the A
isomer [124].
Ligand photodissociation is, of course, a major drawback for the use of
Ru(bpy) ; + as LAS or LES (Sections B (viii) and (ix)). From the above
discussion, it follows that to avoid ligand photodissociation the population
of 3MC and/or ligand dissociation from 3MC should be prevented. Population of 3MC can be prevented or at least reduced by: (a) addition of
sufficient quencher to capture 3MLCT before surface crossing to 3MC can
occur; (b) working at low temperature (Section D (i)); (c) increasing the
energy gap between 3MLCT and 3MC; (d) increasing pressure [145,146]. On
the other hand, ligand dissociation from 3MC can be reduced (e) avoiding
coordinating anions in solvent of low dielectric constant and (f) linking
together the three bpy ligands so as to form a single caging ligand which
encapsulates the metal ion. Points (c) and (f) are particularly interesting and
much effort is presently devoted to research along such directions. The
tuning of excited
state energy by changing ligands (point (c) above) will be
discussed in detail in Section C. Caging Ru2+ into a single polypyridine type
ligand (point (f)) poses severe synthetic problems. A first step in this
direction has been the synthesis [147] of the polypyridine cage-type ligands
shown in Fig. 22. The Ru(I1) complexes of such ligands, however, have not
yet been prepared. Furthermore, there might be subtle problems related to
the shape and size of the cage. If the Ru-N bonds are too long and/or the
bite angles are unfavorable, the ligand field strength would be small and the
consequent decrease in energy of the lowest ‘MC level would compromise
111
m
%3
N
-N
N-
/“\
-
/“\
w
(a)
(b)
Fig. 22. Cage-type polypyridine
ligarrds
11471.
the lifetime of 3MLCT, since caging is not expected to slow down the
physical radiationless deactivation of 3MC [148 1. The short lifetime of
‘MLCT at room temperature for Ru(trpy)$+ (less than 5 ns [149,150]) is
likely due to fast radiationless decay via a low lying 3MC level.
(vi) Quenching
processes
of the 3MLCT
excited
state:
energy
and electron
transfer
As discussed in Section A (ii), an excited state which is sufficiently long
lived may be involved in energy and electron transfer processes in fluid
solution_ The lowest 3MLCT excited state of Ru(bpy)z+ lives long enough
(Table 1) to encounter other solute molecules (even when these are present
at relatively low concentration) and possesses suitable properties to play the
role of energy donor, electron donor, or electron acceptor. As is also shown
in Fig. 23, the energy available to * Ru(bpy)z+ for energy transfer processes
is 2.12 eV and its reduction and oxidation potentials are + 0.84 and - 0.86
V (in water). It follows that *Ru(bpy)s+
is at the same time a good energy
donor (eqn. 27), a good electron acceptor (eqn. 28), and a good electron
donor (eqn. 29) :
Rdbpy):
++ Q -
Ru(bpy)t+
+ *Q
energy transfer
(27)
+ + Q *
Ru(bpy)i+
+ Q-
oxidative quenching
(28)
* Ru(bpy): + + Q -+ Ru(bpy)T
+ Q’
reductive quenching
(29)
*
* WbPYE
The direct observation of redox products in flash photolysis experiments
represents the strongest evidence to support the occurrence of oxidative and
reductive quenching mechanisms. These observations can be performed in a
few cases with continuous irradiation [106,151] and more often in flash
112
Fig. 23. Molecuku quantities of Ru(bpy)$’ relevant for energy and electron transfer
processes. * * Ru(bpy);+ indicates spin-allowed excited states and * Ru(bpy)$+ indicates
the lowest spin-forbidden excited state (3MLCT) Ru(bpy);+ .
photolysis experiments because usually the redox products decay rapidly
either by back electron transfer reactions to reform the starting materials or
by secondary reactions to form other products. In practice, the possibility to
observe transient absorptions is related to the changes in the optical density
of the solution caused by the photoreaction. Bleaching and recovering of the
Ru(bpy) : + spectrum can often be used for kinetic measurements. The
absorption band at 680 nm of Ru(bpy):+
(Section B (i)) is too weak to
detect small Ru(bpy) 33’ concentrations, so that in oxidative quenching
processes one is forced to use the absorption spectrum of Q- to monitor
product formation. By contrast, Ru(bpy)T exhibits a strong absorption band
at 510 nm (Section B (i)), which is particularly useful to investigate reductive
quenching reactions.
Following some pioneering work [151-1551, literally hundreds of bimolecular excited state reactions of Ru(bpy)z+ and of its derivatives have been
studied in the last 15 years. An accurate compilation of rate constants of
electron transfer processes will soon be available [16], so that we do not
review this field in detail. We only wish to illustrate a few examples to show
that these excited state reactions can be used for mechanistic studies as well
as for potential applications of the greatest interest.
The early interest in Ru(bpy):+ photochemistry arose from the possibility
of using its long-lived excited state as energy donor in energy transfer
processes. Although several sensitized reactions attributed to energy transfer
processes (see, e.g. refs. 156, 157) were later shown to proceed via electron
transfer [155], there are a few, very interesting cases in which energy transfer
quenching of * Ru(bpy) z + has been firmly demonstrated. A clear example is
the quenching of * Ru(bpy) z’ by Cr( CN) z-, where sensitized phosphores-
113
cence of the chromium complex has been observed both in fluid solution
[158-1621 and in the solid state [163-1651:
* Ru(bpy);+
(2Eg)Cr(CN);-
+ Cr(CN);j
+ Ru(bpy);+
Cr(CN);-
+ (*&)Cr(CN);-
(30)
+ hv
(31)
was also used to demonEnergy transfer from * Ru(bpy) i’ to Cr(CN)zstrate that the photosolvation reaction observed upon direct excitation of
Cr(CN)zdoes not originate from the luminescent ‘Eg state of the chromium complex [158,166].
It should be pointed out that both reductive and oxidative *Ru(bpy)z+
electron transfer quenchings by Cr(CN)zare thermodynamically forbidden
because it is very difficult to reduce or oxidize Cr(CN)z[162]. Cr(bpy)z+,
by contrast, can be very easily reduced and with this quencher oxidative
electron transfer prevails over energy transfer
* Ru@PY)?
3+
k=3.3X109M-‘s-’
+ Cr(bw)3
)Ru(bpy)?
+ Cr(bpy):+
(32)
as is shown by the appearance of the Cr(bpy);+
absorption spectrum in
flash photolysis experiments [167]. Reaction (32) converts 71% of the spectroscopic energy (2.12 eV) of the excited state reactant into chemical energy
of the products. As usually happens in these simple homogeneous systems,
the converted energy cannot be stored but is immediately dissipated into
heat by the back electron transfer reaction:
2-t
k = 2 X 109M-‘s-’
R@w):+ + Cr(bpy)3 -
R~@PY):
+ + Cr(bpy): +
(33)
A carefully studied example of reductive electron transfer quenching
(reaction 34) is that involving Euii as a quencher [168,169]:
*Ru(bpy);+
2+ k = 2.8 x lO’M-‘s-’
+ Eu..
,Ru(bpy),+
+ Eu3,;
(34)
The difference spectrum obtained by flash photolysis after a 30 ns light
pulse shows a bleaching in the region around 430 nm due to depletion of
Ru(bpy) ; + and an increased absorption around 500 nm due to the formation of Ru(bpy)g (note that both EutT and Eu~: are transparent in this
spectral region). Clear kinetic evidence for reductive quenching comes from
the observation that the growth of the absorption at 500 nm occurs at a rate
equal to the rate of decay of the luminescence emission of * Ru(bpy)$ +. As
it may happen in excited state reactions (Fig. 8(b)) the products of reaction
(34) have a high energy content and thus they give rise to a back electron
transfer reaction
3+
RU(bPY),t + Eu,
k = 2.7 x ~O’M-‘S-~
,Ru(bpy);+
+ Eu2,;
(35)
114
that can be monitored (on a longer time scale) through the recovering of the
430 nm absorption or the disappearance of the 500 nm absorption.
In several cases direct evidence for energy transfer quenching (i.e., sensitized luminescence or absorption spectrum of the excited acceptor) or
electron transfer quenching (i.e., absorption spectrum of redox products) is
difficult or even impossible to obtain. In such cases, free energy correlations
of rate constants are quite useful to elucidate the reaction mechanism
[12,162,170-1721.
(vii) Chemical generation ofthe 3MLCT
eiectrochemiluminescence processes
excited state: chemiluminescence and
As mentioned in Section A (iv), excited states can be generated in very
exergonic electron transfer reactions (Fig. 9). Formation of excited states
can be easily demonstrated when the excited states are luminescent species.
Because of its stability in the reduced and oxidized forms and of the strong
luminescence of * Ru(bpy) g’ , Ru(bpy) $ + is an extremely versatile base
reactant for a variety of chemiluminescent processes [38,39,83,173-1751.
In principle, there are two ways to generate the luminescent * Ru(bpy)$+
excited state in chemical reactions. One way (see eqn. (36)) is to oxidize
more
Ru(bpy) ; with a species X having reduction potential E’(X/X-)
positive than 0.84 V, and another way (eqn. 37) is to reduce Ru(bpy)i+ with
a species Y- whose potential E’(Y/Y-)
is more negative than - 0.86 V (see
also Fig. 23).
Ru(bpy);
+ X ---* * Ru(bpy);+
Ru(bpy);+
+ Y-
+- X-
+ * Ru(bpy):+
* RU(bPYE + + Ru(bpy);+
+ Y
+ hv
A variety of oxidants (e.g. S,Oi- [176,177]) and reductants (e.g., e; [178,179],
N,H,
[180], oxalate ion [181,182], OH- [ISO]) have been found to be active
in these chemiluminescence processes. In some cases (e.g., with OH-),
the
reaction mechanism cannot be a simple outer sphere electron transfer
reaction and the emitting species could be a slightly modified (on the
ligands) complex. It should also be pointed out that minor amounts of
oxidizing and reducing impurities are sufficient to produce luminescence in
chemiluminescence and electrochemiluminescce
experiments [183].
The most elegant way [59] to obtain chemiluminescence from Ru(bpy);+
solutions is to produce the oxidized and/or reduced form of the complex
“in situ” by electrochemical methods. Three classical experiments of this
type can be performed.
115
(a) To pulse the potential applied to a working electrode between the
oxidation and reduction potentials of Ru(bpy):+
in a suitable solvent
[59,184]. In such a way the reduced and oxidized form produced in the same
region of space can undergo a comproportionation reaction where enough
energy is available to produce an excited state and a ground state (see also
Fig. 23):
Ru(bpy):+
+ e- -+ Ru(bpy)c
(39)
Ru(bpy)z+
- e- + Ru(bpy)z+
(40)
Ru(bpy);
+ Ru(bpy);+
-+ * Ru(bpy);+
+ Ru(bpy);+
(41)
in the presence of a strong oxidant (reductive
(b) To reduce Ru(bpy):+
oxidation). For example, luminescence is obtained upon continuous reduction of Ru(bpy) $’ at a working electrode in the presence of S,Oi[176,177].
This oxidant in a first one-electron oxidation reaction generates the very
powerful oxidant SO;
that either can oxidize Ru(bpy)z
to *Ru(bpy):+
(eqn. 43) or Ru(bpy)s+
to Ru(bpy):+
(eqn. 44) which then reacts with
Ru(bpy)g (eqn. 41) to yield the luminescent excited state
Ru(bpy): + + e- -+ Ru(bpy)T
(39)
Ru(bpy);
+ S,O;-
--, Ru(bpy);+
+ SO,
Ru(bpy);
+ SO,
--, * Ru(bpy);+
+ SO:-
(43)
Ru(bpy);+
+ SO,
+ Ru(bpy);+
+ SO:-
(44)
Ru(bpy);
+ Ru(bpy);+
Ru(bpy)z+
- e- -+ Ru(bpy)z+
Ru(bpy);+
+ C20;-
Ru(bpy);+
+ CO,
+ * Ru(bpy);+
+ SO:-
(42)
+ Ru(bpy);+
(41)
(c) To oxidize Ru(bpy) 3’ in the presence of a strong reductant (oxidative
reduction). For example, light is generated upon continuous oxidation of
[181,182]. This
Ru(bpy) ; + at a working electrode in the presence of C,O,‘reductant in a first one-electron reaction generates the strongly reducing
CO;
radical that can reduce Ru(bpy)z W to the excited * Ru(bpy) z’ :
j
(40)
--, Ru(bpy);+
+ CO2 + CO;
(4%
* Ru(bpy):+
+ CO,
(46)
W)
Ru(biy):+ + &Ovv)
(41)
:
+ *Ru(bpy);+
t
Scheme 1
H*
Ru(bpy)g+
(41b))
+ * Ru(bpy):+
+ 1.70 eV
(48)
116
RuUwv) ;+
Ru (bpv)
;
TT@ po)srcL(yI
I0
HM(t,o)6HL(yt
Fig. 24. Pictorial representation of the three possible electronic transitions in the comproportionation reaction between Ru(bpy)i’
and Ru(bpy) l; for details see text.
These chemiluminescent electron transfer reactions are quite interesting
from an applicative [46,47,185] as well as from a theoretical viewpoint. In
particular, the comproportionation reaction (41) poses subtle mechanistic
problems that we will now discuss briefly. As shown in Scheme 1, the
comproportionation reaction in principle can lead to two ground states (eqn.
47), one ground state and one excited state (eqn. 41), or two excited states
(eqn. 48). Furthermore, in the case in which one ground state and one
excited state are formed, the excited state can originate either from the
oxidized (eqn. 41(a)) or reduced (eqn. 41(b)) parent. Formation of two
excited states (eqn. 48) can clearly be ruled out for energetic reasons. Which
one of the three remaining processes takes place (and why) is a matter of
great theoretical interest. Reaction (47) is so exergonic as to fall in the
“ inverted region” predicted by the Marcus electron transfer theory
[23,186,187], and the occurrence of chemiluminescence from the comproportionation reaction with an efficiency for reaction (41) near 100% [188,189]
has indeed been taken as evidence [14,188] in favour of this inverted region.
Although excess exergonicity is certainly a limiting factor in the reaction
rates [17,19,20,31] it should be noticed [190] that reactions (47), (41a), and
(41b), differ from one another because different orbitals are involved. As
shown in Fig. 24, formation of two ground state molecules (eqn. (47))
involves electron transfer from a ligand orbital of the reduced species to a
metal orbital of the oxidized species. Formation of an excited state deriving
from the oxidized species (eqn. 41(a)) involves a ligand-to-ligand electron
transfer, whereas formation of an excited state from the reduced parent
(eqn. 41(b)) requires a metal-to-metal electron transfer. Simple orbital
overlap arguments suggest that the electronic interaction between the two
reaction partners decreases in the electron transfer series L --j L > L += M >
M + M. It follows that reaction (41) is favored over reaction (47) not only
for nuclear reasons (Marcus inverted region), but also because of a more
117
favorable electronic factor via the reaction path (41a). In other words, when
the two reactants of eqns. (47) and (41) approach each other, reaction (41) is
expected to prevail because it can take place over larger separation distances. This simple orbital overlap argument also suggests that reactions
(41a) and (41b), which are exactly identical from a thermodynamic viewpoint and also exhibit the same nuclear intrinsic barrier, may nevertheless
occur with different rates. Unfortunately, there is no simple way to “label”
the reactants and products of the comproportionation reaction and to obtain
experimental data relevant to this subtle mechanistic alternative. Another
interesting chemiluminescent reaction dealing with the Marcus inverted
region has been reported recently [175].
(viii) Ru(bpy)i + as a light absorption sensitizer
As mentioned in Section A (v), there are potential photochemical reactions which do not occur because the reactants are not able to absorb light.
Such reactions can be photosensitized by suitable chemical species that have
been called LAS (light absorption sensitizers) [38]. In the same section we
have also seen that a molecule must satisfy a number of kinetic, thermodynamic, spectroscopic and excited state requirements to play the role of LAS.
It may also be seen from the above discussion (see also Fig. 23), that
satisfies to a noticeable degree most of such requirements and is
Ru(bpy):+
therefore widely used as a light absorption sensitizer [8,13,14,31,38,41,54,191].
Among the great variety of “potential” photochemical reactions that can be
sensitized by Ru(bpy) ’ , an interesting example is that of the reduction of
methylviologen (l,l’-dimethyl-4,4’-bipyridinium
dication, MV2+)
by triphenylamine (NPh,) [192]:
z
MV*’
+ NPh,--j,L>
MV+ + NPH:
AG = + 1.45 eV
(49)
This process is strongly endergonic as a dark reaction but it could be driven
by visible light (i.e., by photons having an energy content higher than 1.45
ev). However, neither MV2+ nor NPh, are able to abSorb visible light, so
that such a “potential” photochemical reaction cannot take place by direct
irradiation:
MV2+ + NPh, + hv-,‘/-•
MV+ + NPh;
AG -C 0
(50)
When Ru(bpy) 5’ is present in the solution, it can be excited by visible light
and its excited state is able to reduce MV*+ to MV+:
Ru(bpy);+
*Ru(bpy);+
+ hv -+ * Ru(bpy):+
+ MV*’
--, Ru(bpy);+
(51)
+ MV+
(52)
118
h3
Fig. 25. An example of the use of Ru(bpy)$+
energy is converted into chemical energy [192].
Using high concentrations of NPh,,
Ru(bpy);+
+ NPh, + Ru(bpy);+
as light absorption sensitizer (LAS):
light
the reaction
+ NPh;
(53)
prevails over the back electron transfer reaction of Ru(bpy)z+ with MV+
and the net result of the experiment is the occurrence of the potential
photochemical reaction represented by eqn. 50, driven by the light absorbed
bY RWPY) ; + (Fig. 25) [192,193].
Much more important for practical applications is the splitting of water
into hydrogen and oxygen by visible light
1/2H,O+hvj/+1/2H,+1/40,
AG=
+1.23eV
(54)
This reaction, which in the dark is endergonic by 1.23 eV, could be driven by
visible photons which, however, are not absorbed by water. In principle,
Ru(bpy) ; + can play the role of LAS even in this case. At pH 7, the
energetics of the relevant steps are as follows:
* Ru(bpy)t+
WbPYX
+ H+ + Ru(bpy)z+
+ + l/2
+ l/2
H,
AG = - 0.44 eV
(55)
AG=
(56)
H,O ---*Ru(bpy);+
+ l/4
O2 + H+
-0.45
eV
In practice, however, reaction 55 is too slow to compete with the excited
state decay. The great number of studies on the problem of the photoinduced water splitting reactions have been reviewed recently by several
authors fl3-15,42-45,194-1981
and will not be discussed any further here.
The conversion of light energy into electrical energy (via intermediate
conversion to chemical energy) is also possible using Ru(bpy)s+
as LAS.
Consider, for example, a cell consisting of two identical compartments
separated by a sintered glass disk and containing a Pt electrode and an
119
‘-pv)$
%idbpy)
‘3’
7
h3
Fig. 26. An example of the use of Ru(bpy)z+
energy (photogalvanic effect) [199].
as LAS: light energy is converted into electrical
aqueous solution of Ru(bpy) s’ and Fe3+ [199]. If one compartment is
illuminated and the other is kept in the dark, an electrical potential is
generated which depends on the incident light intensity (photogalvanic
effect [200]). This potential is due to the difference in the composition of the
solutions in the dark and illuminated compartments caused by the following
reactions (Fig. 26):
Ru(bpy):+
* Ru(bpy)$+
wbPY)z+
+ hv + * Ru(bpy);+
+ Fe3+ -+ Ru(bpy)z+
(51)
+ Fe’+
(57)
can alsobe used to convert light into electrical energy and, at the
same time, to carry on a net redox process. For example, photocurrents can
be obtained from a cell where the net reaction involves the photochemical
oxidation of water by Co(C,O,)~-.
The reaction mechanism is as follows
[201] (Fig. 27):
Cathodic compartment
Ru(bpy);+
* wbPY):+
Ru(bpy)i+
Anodic
OH-
+ hv -
* Ru(bpy):+
+ Co(C,O,);+ e- -
---* Ru(bpy);+
(51)
+ Co2+ + 3C,O,2-
Ru(bpy)z+
(58)
(59)
compartment
- e- -
(ix) Ru(bpyl,2
l/2
H,O,
(60)
+ as u light emission sensitizer
As shown in Section A (v), potential chemihuninescent reactions can be
transformed into effective chemiluminescent reactions by species called light
120
N-
co*++ 3c 2 o*4
Ru(bpW
OH-
4
Ru(bpy)$+
3w32
$
-i-
lRu(bpv)$+
7
h$
as LAS:
Fig. 27. An example of the use of Ru(bpy)z+
energy and to carry on a net redox process [201].
light is used to generate electrical
emission sensitizers (LES) that have appropriate kinetic, thermodynamic,
spectroscopic, and excited state properties [38]. Ru(bpy);+
possesses such
properties to a noticeable degree and is extensively used as LES.
A very interesting example of this type of reaction is that concerning the
well known reduction of lead dioxide by oxalate ions in acid medium
l/2
PbO, + l/2
C20z-
+ 2H+ + l/2
Pb2+ + CO2 + H,O
AG -
- 2 eV
(61)
which would be sufficiently exergonic to produce visible light. In fact, this
reaction produces only heat. However, when the reaction is carried out in
the presence of Ru(bpy)$+, light emission is clearly observed [181]. The
most likely reaction mechanism involves first the oxidation of Ru(bpy)$+ by
by C,O,’ - already discussed to
PbO, and then the reduction of Ru(bpy);+
yield the luminescent *Ru(bpy)z+
excited state (Fig. 28).
Ru(bpy): + + l/2
Ru(bpy);+
+ C20;-
Ru(bpy):+
+ CO;
*Ru(bpy);+
Pb02 + 2H+ --, Ru(bpy);+
+
+ l/2
Pb++ + H,O
(62)
+ Ru(bpy);+
+ CO, + CO;
(45)
* Ru(bpy);+
+ CO,
(46)
--, Ru(bpy);+
+ hv
(38)
In the previously discussed (Section B (vii)) electrochemiluminescent
reactions involving Ru(bpy)c+
and S,Oi- , Ru(bpy)i+
and C20i-,
and
Ru(bpy) z’ alone, Ru(bpy) <’ actually plays the role of LES, as can be better
seen from Figs. 29-31.
In particular, the electrogenerated chemiluminescence process shown in Fig. 31 is to some extent the reverse of the
photogalvanic effect previously seen (Fig. 26) and the processes in which
chemiluminescence is generated by a combined use of chemical and electri-
121
T?ucbPv,$
Ru(b&+
hS
Fig. 28. An example of the use of Ru(bpy);+
energy is converted into light energy [181].
as light emission sensitizer (LES):
chemical
cal energy (Figs. 29 and 30) are to some extent the reverse of the process in
which light carries on a chemical reaction generating a photocurrent (Fig.
27).
The most curious reaction in which Ru(bpy)z+ plays the role of LES is in
the oscillating Belousov-Zhabotinskii
reaction. This very complicated reaction essentially consists of the oxidation of carboxylic acids by bromate ions
(eqn. 63) catalyzed by one-electron redox couples such as Ru(bpy)z+/2+ :
3BrOF + 5CH,(COOH),
+ 3H+
R”(bpy)J3+‘2+PICO, + 3BrCH(COOH),
+ 2HCOOH
+ 5H,O
(63)
This reaction proceeds through periodic rate fluctuations (oscillating reaction) which also cause a fluctuation in the concentration of Ru(bpy):+.
When it was recognized that Ru(bpy)i+ can be reduced by carboxylic acids
thus emitting light (see, e.g., eqns. 45 and 46), it was thought [202] that
because of the fluctuation of the Ru(bpy)i+ concentration and the presence
of carboxylic acid an oscillating chemiluminescence emission should be
Fig. 29. An example of the use of Ru(bpy)z+ as LES: electrical energy and chemical energy
are converted into light energy in a reductive oxidation process [176,177].
Fig. 30. An example of the use of Ru(bpy)$+ as LES: electrical energy and chemical energy
are converted into light energy in an oxidative reduction process [181,182].
h3
Fig. 31. An example of the use of Ru(bpy)3 *+ as LES: electrical energy is converted into light
energy [ 591.
t, min
Fig. 32. Oscillating
Belousov-Zhabotinskii
chemiluminescence
observed
reaction [202] (see text).
using
Ru(bpy):+
as
LES
in
the
123
lRu(bpy) ,‘+
Ru(bpv)$+
H2O
f
Ru(bpy)
;
F - centre
V - csntre
h3
Fig. 33. An example of the use of Ru(bpy)$+
as LES: chemical energy stored into
y-irradiated solids is converted into light (sensitized lyoluminescence) [203].
produced by the Belousov-Zhabotinskii reaction. This expectation was
fulfilled as shown in Fig. 32 which reports the time dependence of the
chemiluminescent signal generated by the reaction. This chemical system
can be considered as an artificial firefly,
Finally, it has been recently shown [203] that dissolution of y-irradiated
NaCl in aqueous solutions containing Ru(bpy)i+ causes generation of the
characteristic * Ru(bpy)z+ luminescence. The reaction mechanism of this
process, where Ru(bpy) z’ mediates the conversion into light of the chemical
energy stored into y-irradiated solids (sensitized lyoluminescence), involves a
complicated sequence of redox reactions initiated by the dissolution in water
of the I;r and V-centres of the irradiated NaCl crystals. First Ru(bpy)G+ is
reduced to Ru(bpy)T or oxidized to Ru(bpy) i’. Then, oxidation of Ru(bpy)l
(eqn. 36) or reduction of Ru(bpy)i+ (eqn. 37) or the comproportionation
reaction (eqn. 41) can yield * Ru(bpy)z+ . This
unusual process where
is
again
involved
as
LES
is
schematically
shown in Fig. 33.
Ru(bpy) : +
C. TUNING
FAMILY
OF EXCITED
STATE
PROPERTIES
IN THE
Ru(II)-POLYPYRIDINE
The Ru(II)-polypyridine complexes find their most extensive and interesting applications as (i) photoluminescent compounds (see, e.g., refs.
124
204-206), (“)
n excited state reactants in electron and energy transfer processes
(Section B (vi)), and (iii) excited state products in electron transfer
chemiluminescence and electrochemiluminescence processes (Section B (vii)).
In this section we will deal with the possibility of changing gradually (i.e.,
“to tune”) the excited state properties that are relevant to the above
processes. This tuning can be performed by judicious choice and combination of the ligands. In this report more than 200 bidentate polypyridine-type
ligands (LL) are contained. In principle, from a group of 200 bidentate
ligands, 200 homoleptic complexes Ru(LL)z+ , 39,800 bis-heteroleptic complexes Ru(LL),_,(LL’)i+,
and 1,313,400
tris-heteroleptic
complexes
Ru(LL)(LL’)(LL”)~+
could be prepared. The synthetic accessibility of the
first (homoleptic) and the second (bis-heteroleptic), and in some cases even
of the third group [207] is another feature of Ru(I1) chemistry, which makes
extensive studies in chemically related series possible.
(i) Orbital
nature of the lowest excited state
As we have seen in Section A (ii), for transition metal complexes only the
lowest excited state (or the lowest manifold of thermally equilibrated excited
states) has a chance to emit luminescence and/or
to live long enough to
participate in bimolecular processes in fluid solution. In d6 transition metal
complexes the MC excited states are strongly distorted compared with the
ground state geometry; this causes fast radiationless deactivation which
prevents luminescence from occurring and precludes the participation of the
excited state in bimolecular processes. LMCT excited states behave in the
same way. By contrast, LC and MLCT excited states, being relatively
undistorted, undergo slow radiationless decay processes so that they can give
rise to luminescence and can be involved in bimolecular reactions. It follows
that the ability to determine the orbital nature of the lowest excited state is a
key step toward the design of useful compounds.
The orbital nature of the lowest excited state can be revealed by examination of the luminescence behavior [48,58,208]. Luminescence arising from a
3MC excited state appears as a gaussian-shaped emission band that is devoid
of structure and considerably red-shifted compared with the lowest energy
absorption bands. The excited state lifetime is relatively long in rigid matrix
at 77 K but decreases rapidly with increasing temperature as does the
luminescence intensity, so that 3MC emission usually cannot be observed in
fluid solution at room temperature. The radiative lifetime is of the order of
10-3-10-5
s, indicating that the triplet character is attenuated by spin-orbit
coupling, as expected for compounds containing a (heavy) metal ion.
Luminescence from 3LMCT excited states is rare [209] and not well
characterized. It can be expected, however, that 3LMCT emission for d6
125
transition metal complexes gives rise to a broad unstructured band exhibiting a large Stokes shift because of the large distortion caused by the
presence of an electron in the a& orbitals [2].
Luminescence from a 3MLCT excited state is generally highly structured
at low temperature, with a prominent vibrational progression [48,58,112114,208,210-2141.
The lifetime at 77 K is in the l-10
ps range and the
radiative lifetime is only - 10 times longer, indicating that the triplet
character of MLCT excited states is also strongly attenuated by the metal
ion. On increasing temperature, the luminescence intensity and lifetime
decrease more or less slowly. Generally, 3MLCT emission is easily observable in fluid solution at room temperature, with lifetimes of the order of
10-1000 ns.
Luminescence originating from a 3LC excited state is usually structured at
low temperature as is the luminescence originating from 3MLCT states.
Usually it is possible to distinguish the two types of emissions on energy and
lifetime grounds [48,58,112,115,117,118,214,215].
3LC emission occurs quite
close to (usually, - 1000 cm-’
red-shifted from) the emission of the free
ligand, whereas 3MLCT emission can occur, of course, at much lower
energies. Furthermore, the 3LC emission is less influenced by the (heavy)
metal ion, so that it maintains its spin-forbidden character to a larger degree
than the 3MLCT emission. Thus, the radiative lifetime of 3LC emission is
usually > 10e4 s. This relatively slow radiative decay can compete with the
slow radiationless decay at low temperature in rigid media, as shown by the
appearance of 3LC emission bands in rigid matrix at 77 K. In fluid solution
at room temperature, however, 3LC emission can seldom be observed
because of the occurrence of faster (thermally activated) t&molecular decay
processes and/ or bimolecular quenching processes.
It has been known for a long time [48,49,58] that in a series of complexes
of the same metal ion one can determine the orbital nature of the lowest
excited state by a suitable choice of ligands. The energy of the MC excited
states depends on the ligand field strength, which in its turn depends on the
a-donor and Ir-acceptor properties of the ligands, the steric crowding around
the metal (that can preclude a sufficiently close approach between metal and
ligand) [40], and the bite angle of the polydentate ligands (which in some
cases cannot be optimized because of molecular constraints (see, e.g., ref.
216)). The energy of the MLCT excited states depends on the reduction
potential of the ligand involved in the MLCT
transition, the oxidation
potential of the metal in the complex (which is affected by the ‘electron
donor and acceptor properties of all the ligands), and by the charge
separation caused by the transition. The energy of the LC excited states
depends on intrinsic properties of the ligands, such as the HOMO-LUMO
energy gap and the singlet-triplet splitting.
126
The luminescence of Ru(bpy) :’ is a typical 3MLCT emission 1481: (i) it
than the phosphorescence
occurs at much lower energy ( vmax= 17 200 cm-‘)
of free bpy ( vmax= 23 100 cm-l);
(ii) the luminescence spectrum is structured at low temperature; (iii) the radiative lifetime is - 13 ps. Most of the
known Ru(II)-polypyridine
complexes (Table 1) exhibit a luminescent behavior quite similar to that of Ru(bpy) g’ , indicating that the lowest excited
state is a 3MLCT state. By an appropriate choice of the ligands, however, it
has been possible to change the orbital nature of the lowest excited state.
3MC emission can be obtained decreasing the ligand field strength, e.g.
replacing one or two polypyridine ligands by Cl- ions [217]. It should be
noted, however, that the m-donor ability of the Cl- ligand also lowers the
energy of the MLCT excited states by increasing the negative charge on the
metal. Thus, when the Ru(LL) z’ compound has a 3MLCT excited state at
very low energy (as is the case for LL = biq or DMCH),
substitution of LL
by 2Cl- does not cause an inversion on the excited state energy ordering_ A
case in which a clean 3MC emission can be observed is Ru(i-biq),Cl,
[217].
3LC emission can be obtained using polypyridine ligands which satisfy
the following requirements: (i) presence of a relatively low-lying 3LC level;
(ii) sufficiently high ligand field strength to keep 3MC at high energy; (iii)
sufficiently negative reduction potential to keep 3MLCT at high energy. The
i-biq ligand apparently satisfies these requirements [2X5]. A clear example of
tuning of the excited state orbital nature is shown in Fig. 34. For Ru(i-biq)i+
,
emission is clearly 3LC in nature, as shown by: (i) the shape of the
luminescence spectrum, which is identical to that of the free i-biq ligand; (ii)
the energy of the emission maximum, which is less than 1000 cm-l
red
shifted compared with that of the free ligand; (iii) the relatively long
emission lifetime at 77 K (96 ps). When an i-biq ligand is replaced by bpy,
which has a higher 3LC, a similar ligand field strength, and is easier to
I’.“‘.““‘.
l””
Fig. 34. Emission spectra of Ru(i-biq)z+
[217].
(a), Ru(i-biq)2(bpy)2+
(b), and Ru(i-biq)2C12
(c)
127
reduce, the emission (Fig. 34) moves to the red, exhibits a different structure
and a shorter lifetime at 77 K (5 ps), maintaining a high intensity in fluid
solution at room temperature, as expected for a 3MLCT (specifically,
Ru - bpy) emitting level 11281. When an i-biq ligand is replaced by two Clligands, the emission moves further to the red, becomes broad, unstructured,
shorter lived (2.2 ps), and can no longer be observed at room temperature as
expected for a 3MC emission [217].
Interestingly, a tuning between 3LC and 3MLCT can also be obtained by
changing the acidity of the solution [218,219].
This happens for the
Ru(LL),(CN),
complexes (LL = bpy,phen,i-biq) [218-2201 where the CNligands can be protonated at their nitrogen end. The unprotonated forms of
the complexes exhibit the usual 3MLCT emission. Protonation withdraws
negative charge from the metal, thus moving the MLCT (Ru - LL) levels to
higher energy, leaving the LC levels unaffected. For the diprotonated
species, the emission clearly exhibits 3LC character as shown, for example,
by the extremely long lifetime (8800 ps) of Ru(i-biq) *(CNH) i+ in H2S04 at
77 K [220].
Another interesting case of tuning of the orbital nature of the lowest
excited state by changing the pH of the solution occurs in the complexes of
2,2’-dipyridylamine (HDPA) and its deprotonated form (DPA-)
[209]. For
the complexes of the deprotonated ligand the lowest excited state appears to
be, quite unusually, a 3LMCT level.
As mentioned above (see also Table l), in the great majority of
Ru(II)-polypyridine
complexes the lowest (luminescent) excited state is a
3MLCT level (or a cluster of 3MLCT levels). For a systematic use of these
complexes in luminescence and chemiluminescence
experiments and in
energy transfer processes it is important to have a series of complexes
covering a broad range of excited state energies. This can be doie by (i)
changing the type of ligand involved in the formation of the MLCT excited
state, (ii) controlling the amount of negative charge on the metal by changing the nature of the ligands, and (iii) changing the solvent interaction. The
parameters to be taken into consideration are the reduction potential of the
free ligand, the u-donor ability of the ligand (which is related to the pK, of
the free ligand), m-donor and acceptor properties of the ligand, the charge
separation in the excited state (since the coulombic interaction between the
hole on the metal and the electron on the ligand decreases with increasing
separation distance), and solvent parameters which govern the complexsolvent interaction (dielectric constant, donor and acceptor numbers, etc.).
128
Big changes in the excited state energy can be obtained on changing the
ligand involved in the MLCT (e.g., compare Ru(bpy);+ with Ru(bpy) Z(biq) 2+
(Table 1)), while substitution on the ligand aromatic rings offers the opportunity to carry on a fine tuning (e.g., Ru(bpy):+
vs. Ru(4,4’-dm-bpy)$+).
Considerable changes in the excited state energy can also be obtained upon
substitution of the ligand not involved in the MLCT transition (e.g., Ru
(bpy)(i-biq) z+ vs. Ru(i-big) #X2), and on changing the solvent when a mixed
ligand complex undergoes a strong solvent interaction (e.g., Ru(bpy),(CN),
[221] and Ru(bpy)(CN) i- [222]). For complexes containing only one type of
ligand (e.g., Ru(bpy):+)
the solvent effect is very small 198, 2231.
(iii) Excited
state redox properties
As we have seen in Section A (ii) the excited state redox potentials are
given, to a first approximation, by eqns. 8 and 9 and thus they can be tuned
by changing the ground state redox potentials and/or
the excited state
energy. It should also be noted that, with a few exceptions, the redox and
spectroscopic orbitals are the same for each Ru(II)-polypyridine
complex
[65], so that ground state redox potentials and excited state energy are
quantities related to one another (see Section D (ii)). Since reduction usually
takes place on a ligand, the ground state reduction potential will be roughly
related to the reduction potential of the free ligand (compare, e.g., the first
reduction potentials of Ru(bpy)g+ and Ru(biq)$+ , Table 3, with those of the
free ligands: EO(bpy/bpy-)
= - 2.22 V; E’(biq/biq-)
= - 1.75 V). However, the ability of a coordinated ligand to accept an electron also depends
on the amount of charge transferred to the metal or received from the metal
via the cr and TTT
bonding by the other ligands. It should also be recalled that
the changes in the reduction potential of the ground state do not cause an
equal change in the reduction potential of the excited state because the
energy of the 3MLCT level decreases as the ligand becomes easier to be
reduced.
Oxidation of Ru(II)-polypyridine
complexes usually consists in the removal of an electron from a mM(d) metal orbital. The oxidation potential,
however, is affected by the nature of the ligands because the amount of
electric charge localized on the metal (and thus, the tendency to lose an
electron) is governed by the u and w properties of the ligands. For ligands
of the same series, the presence of electron withdrawing groups increases the
oxidation potential while the opposite occurs, of course, for electron donating substituents. Linear correlations between the reduction potential of the
complexes and the Hammet u constants of the free ligands have been
obtained for 4,4’- and 5,5’-disubstituted bpy 12241. A change in the oxidation potential of the ground state causes a change in the excited state
129
oxidation potential. The relationship between spectroscopic and redox quantities will be discussed in more detail in Section D (ii).
In conclusion, the factors which govern the excited state redox potentials
are known and can be manipulated by changing the structure of the ligands.
Hundreds of Ru(II)-polypyridine
complexes having variable redox potentials in the excited state (and, of course, in the ground state) are now
available (Table 3). This is particularly useful for systematic studies where
homogeneous series of powerful oxidants or reductants are needed (Section
A (iii)).
D. OTHER
SELECTED
(i) Emission
TOPICS
lifetime and its temperature
dependence
As we have seen in Section A (ii), the decay of an excited state takes place
by competitive radiative and non-radiative processes. This can be expressed
by the following equation
l/7
= k’ + k”’
(64)
where r is the excited state lifetime and k’ and k”’ are the radiative and
non-radiative rate constants.
The temperature dependence
of the emission lifetime
of several
Ru(II)-polypyridine
complexes in the temperature range 1.8-77 K in polymethylmethacrylate matrices has been carefully investigated [107-111.,123].
The luminescence was found to originate from a cluster of three closely lying
levels (AE lo-100
cm-‘) which are in Boltzmann equilibrium, each having
its own radiative and non-radiative temperature independent rate constant.
In this review, we are more interested to examine the temperature
dependence of the luminescence lifetime for temperatures from 77 K to
room temperature. For this purpose, the two levels separated by 10 cm-’
can be dealt with as a single level and their radiative and non-radiative rate
constants account for most of the temperature independent lifetime at 77 K.
While the rate of the radiative transition is essentially governed by spin and
symmetry factors [48], the radiationless rate constant generally increases
with decreasing excited state energy, as expected on the basis of the energy
gap law [142]. As the temperature increases, the luminescence lifetime is
found to decrease with a behavior which is different from complex to
complex. Significant examples are shown in Figs. 20 and 35. To account for
such-behavior, l/r can be expressed as a sum of a temperature independent
and several temperature dependent terms:
l/r
= k, + Ck_Y(T)
(65)
130
Ln ’
z-
16 -
15-
14-
12(C)
(b)
13-
l2
12(b)
I
I
I
2
6
1000/T,
1
10
1
K-’
Fig. 35. Temperature dependence of the emission lifetime of Ru(biq);+
(a), Ru(bpy) 2(CN) 2
(b), and Ru(taphen)$+ (c). Curves (b) and (c) are shifted along the ordinate axis as indicated.
The temperature dependent terms can be associated, in a schematic way,
either to (a) an activated surface crossing to another excited state, described
by the Arrhenius equation
ki”’
=
Aie-AE/RT
(66)
or (b) to the coming into play of vibrational modes that can favour the
radiationless decay and that are prevented at low temperature because of the
frozen molecular environment; this second type of thermally activated
process can be dealt with by the following equation
Bi
k”= 1 + exp[ Ci(l/r
- l/TB,)]
(67)
which describes stepwise behavior centered at a certain temperature T’;_ In
eqn. (67), Ci is temperature-related to the smoothness of the step and Bi is
the value attained by ki at T Z+ T’,,. A way in which eqn. (67) can be derived
from arguments based on dielectric relaxation processes has been reported
[137j. This equation is particularly useful for describing the behavior of a
system in the glass-fluid transition region of a solvent matrix.
The l/r
vs. l/T
plots (Figs. 20 and 35) can usualIy be fitted by using
eqn. 65, with an appropriate number of terms given by eqns. (66) and (67).
For Ru(biq) z’ (Fig. 39, only on e term of the type of eqn. (66) and one term
131
of the type of eqn. (67) are necessary to account for the behavior observed
[ 1281. For Ru(bpy); + (Fig. 20), two eqn. (66) terms and one eqn. (67) term
are needed [131]. For Ru(bpy),(CN),
(Fig. 35), two eqn. (66) and two eqn.
(67) terms are required [137]. For Ru(taphen)s+ (Fig. 35), the behavior is
extremely complicated and cannot be fitted with a reasonably simple
mathematical equation [136]. When a narrow temperature range concerning
fluid solutions is examined, eqn. (67) terms, of course, are not required.
There is general agreement [95,119,121,124,129,137,210,225]
in the literature that the Arrhenius type term
k, = A, e--hEJRT
(68)
which accounts for the temperature dependence of the luminescence lifetime
at high temperature (T > 250 K) is related to an activated surface crossing
from the 3MLCT manifold to a 3MC level (eqn. 69) which undergoes
photochemical and/ or photophysical deactivation (eqn. 70)
3
k
A3
MLc%Y+
(69)
Mc
3,,%ground
state and/or
photoproducts
(70)
Note that k, represents the sum of all the rate constants of the processes
that deactivate 3MC, with the exception of the back surface crossing to
3MLCT. The experimental deactivation rate constant that comes into play at
high temperature (eqn. 68) can be expressed as follows on the basis of eqns.
(69) and (70):
k, = k,[kJ(k,
+ &)I
(71)
Eqn. (71) can give rise to two limiting cases (Fig. 36).
(i) When k, S- k,, the decay of 3MC is rapid and eqn. (71) becomes
k, = k,
(72)
It follows that
A, exp( -AE,/RT)
= A, exp( -AEJRT)
(73)
In this limit, the A, and AE, parameters obtained from the fitting correspond to the pre-exponential factor and activation energy for the 3MLCT
- 3 MC surface crossing (Fig. 36(a)). It follows that for complexes whose
3MC_ excited state undergoes a very fast decay, the only way to maintain a
long excited state Lifetime in fluid solution at room temperature is to have a
large activation energy for the 3MLCT --* 3 MC surface crossing. The energy
barrier for this surface crossing is presumably related to the energy gap
between the zero-zero energies of the two states. Thus, in principle, this
132
(a)
M-L
M-L
M-L
Fig. 36. Schematic representation of the situation of the potential energy surfaces for the
three limiting cases described in the text [137].
activation energy can be tuned by tuning the energy of the 3MLCT and 3MC
excited states as described in Section C (ii).
(ii) When k, S-F=k,, the decay of 3MC is slow compared to the back
surface crossing to 3MLCT. In such a case, the two states are in equilibrium
and eqn. (71) becomes
(74)
k = k/k&c
exp(AS/R),
where AE and AS are the
Since kJk, = K= exp( -AE/RT)
internal energy and entropy differences between 3MLCT
and 3MC, it
follows that
A, exp( - AEJRT)
= k, exp[ - AE/RT]
exp[ AS/R]
(75)
133
Neglecting the entropic difference between the two states, which is expected
to be small, eqn. (75) can be re-written as
A, exp[ -AEJRT]
= k, exp[ -AE/RT]
(76)
The meaning of the experimental quantities A, and AE, depends on the
nature of the processes that contribute to k,. The following limiting cases
are of interest.
(ii-a) When the major contribution to k, comes from a chemical reaction
or a deactivation process that can be described by an Arrhenius-type
equation, eqn. (76) can be written as
A, exp[ -AE,/RT]
= A, exp[ - (AE,
+ AE)/RT]
(77)
In such a case, the A, and AE, parameters obtained from the fitting of the
l/r
vs. l/T
plot correspond to the pre-exponential factor of the decay
process of 3MC and to the sum of the 3MC-3MLCT
energy gap and the
activation energy of the decay process of 3MC (Fig. 36(b)).
(ii-b) When the main contribution to k, comes from a non-activated
process kb, from eqn. (76) it follows that the pre-exponential parameter A,
corresponds to the rate of the non-activated 3MC decay, kb, and the
activation energy AE, corresponds to the 3MC- 3MLCT energy gap, A E
(Fig. 36(c))_ Thus, even in cases (ii-a) and (ii-b) the lifetime at room
temperature can be tuned by an appropriate tuning of the energies of the
3MLCT and 3MC levels via the choice of suitable ligands (Section C (ii)).
The meaning of A, and AE, in the three limiting cases described above is
as follows (see also Fig. 36). In principle it can be expected that A, and A,
are high frequency (1013-1014 s-i ) vibrations whose activation leads to the
surface crossing region (Fig. 36(a) and (b)). By contrast, k: can be much
smaller because it represents the rate constant of radiationless transition
having a poor Franck-Condon
factor (Fig. 36(c)). Ru(bpy)g+
(A, 1013-1014 s-l
AE - 4000 cm-‘) [128,129] is thought to belong to case (i)
however, on the basis of the values of A, and AE= it is
[124,129,210,225].
not possible to distinguish between case (i) and case (ii-a). Several other
Ru(I1) polypyridine complexes [131,133,135,210,225],
exhibit comparable A,
and AE, values and are also considered to belong to the same (i) limit. The
A, and AE, values for Ru(bpy),(CN),,
however, are quite different (A, - 3
x lOlo s-l,
AE, = 2400 cm-‘)
[137]. In particular, the value for A, is too
low to correspond to the frequency factor of a surface crossing process. This
suggests that Ru(bpy),(CN),
represents a limiting case (ii-b).
(ii)
Correlations
between spectroscopy
and electrochemistry
The ruthenium polypyridine complexes are well suited for the study of
correlations between electrochemical and spectroscopic properties [226-2401
134
E&l
1
E,/2(2)
%/z(3)
t
Fig. 37. Schematic diagram showing pictorially the three reduction processes relevant to a
discus&on
of the correlation between spectroscopic and electrochemical properties in a
Ru( LL’ ) unit.
because a large number of such complexes can be reduced and oxidized in
reversible one-electron steps (Table 3) and a wealth of information is
available on absorption and emission spectra (Table 1). Relations of this
type have been studied in both homoleptic and heteroleptic Ru(II)-polypyridine complexes. In the latter a very simple assignment of the absorption
bands and of the reduction waves is often possible. When two polypyridine
ligands which are sufficiently different in their redox behavior, such as biq
and bpy, are present, generally dual MLCT absorption is observed, and the
successive reduction waves can be assigned to a “localized” reduction in a
single ligand (see, e.g., ref. 239).
For Ru(LL)*(LL’)~+
complexes, where LL’ is the ligand easier to reduce,
the relevant reduction potentials to establish the correlation between spectroscopy and electrochemistry are E1,2 (I), E42),
and Eli2(3) [2331, which
correspond to the following processes (Fig. 37)
(W2W’)l
3+ + e- -+ [Ru2+(LL),(LL’)12*
(78)
G/2 (1)
b3+
E1,2(2)
[Ru2+(LL),(LL’)12+
+ e-
---, [Ru~+(LL)~(LL’-)]~+
(79)
E1,2(3)
[Ru~+(LL)~(LL’)]~+
+ e- -+ [Ru~+(LL)z(LL’-)]~+
(80)
The values for E1,2(1) and E1,2(2) can usually be obtained, whereas
E1,2( 3), which corresponds to reduction of LL’ in the Ru3+ field, is a
quantity not directly measurable (for Ru(bpy)z+ , it is estimated to be - 0.8
V vs. SCE in acetonitrile [2333). If the lowest lying triplet excited state is
formed by a single configuration d + 7r* (LL’) transition occurring between
135
>
iu^ -1.5 ’
q
W’
l
i
= 1.16
= 0.66
l i
-0.5 1
I
-1
-2
E,/2 (LL’), v
Fig. 38. Correlation between the first reduction potential E,,,(2)
of some selected Ru(LL’):+
or Ru(LL),(LL’)~+
complexes and the reduction potential Q2(LL’)
of the free LL’ ligand.
Ru(i-biq)$+
(a); Ru(i-biq),(bpy)2+
(b); Ru(phen)$+
(c); R~(bpy)~(4,4’-dph_bpy)~+
(d);
R@PY) ~(bpym)~+ (e); Ru(bpy)2(~@2+
(0;
Ru(b~y)~Wp)~+
(0; and Ru(bpy),(taphen)‘+
only the open circle data [240].
R~@PY) 2(bi@2+
(g); Ru(bpy) 2(b~z)2+
(h);
0). Th e regression has been performed using
the same orbitals that are involved in the electrochemical processes and the
entropy difference between ground and excited state is negligible, the O-O
triplet excited state energy is given by
h%I(T) = e[ Et,,(L) - E,,,(3)]
+ XI(81)
where X, is the triplet charge transfer interaction energy.
The structure of LL’ largely determines the electrochemical and spectroscopic properties of Ru-polypyridine
complexes. Figure 38, for example,
reports the first reduction potential,
E1,2(2),
of some Ru(LL’)g+
or
Ru(LL)~(LL’)~+
complexes compared with that of the free hgand, E1,2(LL’)
[240]. The good correlation (with the exception of two complexes, vide infra)
indicates that the reduction of the complexes involves a “spatially isolated”
v *(LL’)
ligand orbital (Section D (iii)) which largely resembles the free
ligand orbital. Furthermore, u-donor and ?r*-acceptor properties of the
ligands are expected to affect the oxidation process (removal of an electron
from a metal d orbital). Stronger a-donor ability (higher pK,) results in
lower formal charge of Ru2* and consequently in a lower oxidation potential of the complex [224,230,232,234,241].
On the other hand, A-72 * interaction causes a certain amount of d-orbital stabilization (and m* orbital
destabilization) which may lead to a higher oxidation potential. Substituent
effects on the oxidation potential of Ru(bpy)$+
derivatives have been
systematically investigated [224].
E1,2(3) is related to E1,2(2) by the following equation:
Er12 (3) = G/2
(2)
+
(a’
-
0
032)
136
where a! and S ’ are potential terms which take into account the energy
changes due to changes in charge repulsion (a) and solvation (S) on passing
from Ru3+ to Ru2+ fields. Substitution of eqn. (82) into eqn. (81) yields
hv,(T)
= A&,,
- (ar - S) + X,
(83)
where A EI,z is the so called “redox energy”, given by
A&,2
=
e [ El,2
(1)
-
El,2
m]
(84)
The term (cy - S) is estimated to be 0.5 eV in Ru(bpy)G+
Equation (83) gives rise to eqn. (85)
/W&~(T)
= AE,,,
-((Y-.SS)+X~-A(~Y)~
[233].
(85)
where A( hv), takes into account the distortion energy for the triplet state.
As can be seen, the linearity between hz~&““,and A E1,2 depends on the
constancy of ((x - S), Xr and A( hv), along a Ru-polypyridine
series. For
the lowest excited singlet state
hv,(S)
-/W,(T)
= 2K+
X, - X,
(86)
where K is the exchange energy and Xs is the singlet interaction energy.
Equation (87) then follows, where A( hv), takes into account the distortion
energy for the singlet state:
&n,abs-- AE,,,
- (a - S) + 2K-k
X, - XT + A(hv)s
(87)
Typical values for Ru(bpy) 3_ n(LL) i’ complexes are: A( hv), = A( hv) r = 0.1
eV; K = 0.1 eV; X, = 0.3 eV [233].
A different approach [236,237,242],
based on the use of a free energy
diagram relating optical (absorption) energies and electrochemical quantities, leads to eqn. (88) :
hv,“b
=
AE,/,
+ Q + AAGs + A(so~)
+ Xi + X0
(88)
where xi and x0 are the inner (vibrational) and outer (solvation) reorganization energies in going from the ground to the excited state related to A( hv) s,
Q is the energy required for the gas phase process M(LL)3+ + M(LL)+ j
M(LL)2+ + * M(LL)2+,
AAG, includes the free energy changes due to the
different solvation of the ground state compared to its oxidized and reduced
forms, and A(so1) includes the solvation free energy of the ground and
excited state species. Equation (88) has been used to obtain values of x0 for
Ru --, LL and Ru - LL’
transitions in the Ru(bpy) 2(LL’)2+
and
Ru(bpy)(LL’)s+
series [236].
Equations (87) and (88) and eqn. (85) can be written as eqns. (89) and
137
li
slope
- 1.09
= 0.83
= 0.98
D
’
I
I
2.4
2.8
AE,/,
,
, ev
Fig. 39. Correlation between absorption (a) and emission (b) energies and redox energy AE,,,
for the same complexes of Fig. 38 [240].
(90) for the absorption and emission maxima, respectively, with a = b = 1
and A z B.
hv,,,=a
(89)
AE,,,+A
h%nl = b AE,,,
+ B
(90)
Figure 39 shows the correlations between optical energies and AE,,,
for
some representative Ru-polypyridine
complexes [240]. The coefficients are:
a = 1.09, A = - 0.05 eV; b = 0.83, B = -0.18
eV. Generally, b is found to
be significantly lower than unity [232,238], which may be taken as an
indication that the d - T * single configuration description is an approximation not fully valid for the case of emission.
As discussed above, the correlation between spectroscopy and electrochemistry lies on the assumption that the “spatially isolated” ‘1~* acceptor orbital is the same both for the reduction process and the CT transition
resulting in the ligand localized excited state. Furthermore, correlations can
also be expected between the reduction potentials of the coordinated and
free ligand, because the same m* lowest unoccupied molecular orbital
138
I
-11
LllMO energy, eV
Fig. 40. Correlations of the reduction potential of the free l&and (a) and of the correspondent
ruthenium complex (b) with the LUMO energy of the free ligand [240]. For identification of
complexes, see caption of Fig. 38.
(LUMO) is involved. Extended Huckel (EH) MO calculations on a series of
unsubstituted ligands have been performed 12401 with the aim of studying
the effect of increasing conjugation on the spectroscopic and electrochemical
properties. Figure 40(a) shows that E,,,(LL’)
is correlated, as expected, with
the calculated ligand LWMO energy. As seen above, the plot of E,,,(2)
vs.
E,,,(LL’)
also results in a linear relation (Fig. 38) except for complexes
containing the ligands taphen [136] and DP [243]. Similarly, the plot of
(Fig. 40(b)) exhibits deviations for complexes containing
E1,2(2) vs- %“MO
taphen and DP. Explanation for these deviations have recently been discussed [240].
(iii) Localization and deloca Zization problems
The problem of the localization or delocalization of the excitation is
concerned with the description of the excited state * Ru(LL)i+
as
[Ru~+(LL)~(LL+)]*+
or as [Ru~+(LL-~/~)~~*~.
The former case corresponds to a situation in which the promoted electron resides for a certain
amount of time on a single ligand (Fig. 15(b)). The latter case describes a
situation in which either the electron is completely shared by the three
139
Fig. 41. Energy level scheme ( D3 symmetry) in the e.i.c. model [ill] for the MLCT states
responsible for the emission of Ru(LL)$ + complexes. The energy separation between the A,
and E and A, and A2 states is of the order of 10 cm-’
and 50 cm-‘,
respectively, in
RNbpy) $ + .
ligands or it undergoes hopping from ligand to ligand faster than the
resolution time of the monitoring technique (Fig. 15(a)).
Models concerned with the excited state structure of Ru(II)-polypyridine
complexes have to take into account a very large body of literature
[50,65-67,69,71-74,93,98,99,102,107-111,123,141,211,244-314].
The reference model of delocalization, as derived from studies of luminescence, is the electron-ion coupling (e.i.c.) model [107-111,123].
This model
leads to a description of the lowest energy d + VT* configurations as a set of
three levels. The promoted electron resides in an orbital ( a2 in OS symmetry) based on the lowest antibonding orbitals, Gcli,of each ligand and
encompassing the three ligands:
In this model the ligand-ligand overlap is explicitly disregarded and the
exchange interaction between the excited electron and the electrons remaining in the d5 core is held responsible for the splitting among the energy
levels (scheme shown in Fig. 41). Infinite separation of the promoted
electron and the metal core would result in a fourfold degenerate state. The
e.i.c. model was also proposed to describe mixed-ligand
chelates like
Ru(bpy), (phen) $?, [II l] by assuming an electronic symmetry ( OS) higher
than that of the molecular structure.
The localized description assumes C,, symmetry for the hypothetical
Ru-LL unit [245,263] (Fig. 42). Complete localization, i.e. excitation localized on decoupled ligands throughout the lifetime of the emitting species,
seems unlikely because in this case both the emission spectrum and lifetime
of mixed ligand complexes should exhibit dual behavior [257,268], as found
for Rh(bpy), (phen): ?, complexes [111,249], that is not actually observed for
the Ru complexes [274,275,315].
A simple treatment for the charge transfer transition intensities can be
based on the localized fragment of Fig. 42. Here, the interaction between the
140
@
4. =
‘. -n;;.(b,)
tzg w--.
LL
P
_L
.
RU
LL’
Fig. 42. Localized Ru-LL’ fragment under C 2v symmetry: (a) orbital interaction scheme; (b)
Iigand antibonding and metal orbitals of bl symmetry.
bF( t,,) metal orbital and the by( 9) ligand orbital leads to a bonding
combination bl(fzg) mainly centered on the metal and to an antibonding
combination b,( a,!~)mainly centered on the ligand
(93)
~IW = w/JC/)- Wh,)
(94
where c is the first order mixing coefficient. From group theoretical considerations the d ---, VT
* transition for the localized fragment is polarized along
the C, axis, that is in the direction of the charge transfer from the metal to
the ligand, In this case, the transition moment jX is mainly due to the
transfer term [245,263]
F=cqS
(95)
where q is the electronic charge and % is the position vector of the ligand
center. On these grounds, for a Ru(LL) z’ complex (D, symmetry) one
should expect that transitions polarized along the individual C, axes do not
provide intensity parallel to the C, axis. This is only partly consistent with
the absorption spectrum of Ru(bpy)g+ observed in host single crystals at 8
K 12591 which is mainly polarized in the direction perpendicular to the C,
axis but is also entangled by a weaker component polarized parallel to C,.
141
I
400
500
x ,nm
600
Fig. 43. Absorption spectra in alcoholic solution at room temperature of Ru(bpy)z+
Ru(bpy)2(biq)2+
(b), and Ru(biq);+
(c) [128].
(a),
The prediction of separate charge transfer bands based on the localized
model is verified for the charge transfer absorption spectra of complexes
containing non-equivalent ligands. For example, in Ru(bpy),(biq)zT,
and
other mixed ligand complexes ([128,274], Fig. 43) two well separated MLCT
bands have been observed, the lower energy one corresponding to promotion
of the electron to the ligand easier to reduce. However, even a delocalized
model including weak interligand coupling [263] predicts that the MLCT
absorption in trischelated complexes should indeed be characterized by two
distinct absorption bands.
The electronic spectrum of Ru(bpy) z’ in host single crystals at 8 K has
been interpreted according to D3 symmetry 12591. Two spin-allowed transitions perpendicular to the C, axis were described as involving ligand Gorbitals
of + and x origin. Polarized emission of [Ru(bpy),](PF,),
single- crystals
was observed in the temperature range 243-343
K by exciting at 488 nm
@th E IIc (C, axis) [282]. The emission was found to occur mai$y with
E J_ c, but a red-shifted activated emission (E = 650 cm-‘)
with E IIc was
also found. In the frame of D3 symmetry the main emission was ascribed to
E states while the red-shifted emission was ascribed to an A, state. Similar
results were obtained extending the explored temperature to the 1.6 - 300 IS
range [286]. On the basis of the temperature dependence studies of the
polarized emission spectrum an energy ordering for the lowest energy
excited states ( D3 symmetry) was proposed that includes up to five states in
a 800 cm-l range.
142
The analogy between the singly-reduced species, which has been observed
by spectra-electrochemical
measurements and described as [Ru2’(bpy) 2
(bpy-)]+
(Section A (vii)) [71,72,93,289]
and the excited species [ * Ru3+2f
helps
in
modeling
the
excited
state potential curves for the
(bpy) ,(bpy- )I
localized case [65,66]. One gross feature should be the presence of potential
barriers for the transfer of the electron from ligand to ligand. A model based
on Franck-Condon
overlap between the trigonal ground state and the three
equivalent asymmetric excited states has led to three minima as in the case
of the reduced complex [289]. Therefore, the excited state potential energy
profile could be used for the same parameters found for the singly-reduced
species by temperature dependent ESR studies, i.e. the electron hopping
should experience a barrier of about 700-1000
cm-’
depending on the
solvent employed 167,691.
Concerning the spin properties, on the basis of the high efficiency of
energy transfer from the luminescent * Ru(bpy)z+ excited state to dyes with
formation of excited singlet dyes it has been suggested that * Ru(bpy)$+ has
a great deal of singlet character [51]. However, the singlet character of each
of the three low-lying MLCT levels should not exceed 10% according to a
recent electronic model [50] for the interpretation of absorption spectra of
M(bpy) ; + complexes (M = Fe, Ru, OS).
In an attempt to establish a symmetry labelling and energy ordering of
the lowest excited states, both D, and C, symmetry sites have been
examined [316]. Four states can be predicted to lie at low energy in a
localized MLCT configuration for Ru and OS complexes, three of them
being closely spaced ( < 200 cm-‘) and the fourth occurring several hundred
to higher energy [284]. Molecular orbital calculations performed for
cm-l
Ru( LL) $+ complexes in the frame of trigonal symmetry and using multiple
scattering Xa and EH models satisfactorily compare with the known lowtemperature single crystal absorption spectrum of Ru(bpy):+
[264]. The
assignment of the MLCT transitions occurring at 21500 and 23 400 cm-’
was based on the involvement of the lowest antibonding + orbital of the
ligands, since the ligand x orbital lies at much higher energy (see Section A
(vi)). Interpretation of the CD spectrum of Ru(bpy)g+
as resolved into
many components based on the lowest energy 4 orbital has led to the same
conclusions [2621.
Photoselection studies on Ru(bpy) i + and related complexes indicate that
the emitting state is localized on a single ring [255,269] and temperature
and
dependent data suggest that both intermolecular (solvent-solute)
intramolecular mechanisms are active in single ligand localization of the
excitation for Ru(bpy)z+ and Ru(phen)z+ [290,314].
Other studies basically employing absorption or luminescence spectroscopy [271,272,294,295,304]
have tried to elucidate the localization prob-
143
lem, also with special emphasis on viscosity dependent relaxation effects
[132,293,303,305,306,310,311].
Studies based on resonance Raman spectroscopy have provided evidence
for localization of the excitation both in mixed ligand complexes and in
complexes containing equivalent ligands [74,102,253,299,307].
Time resolved
resonance Raman (TR3) studies of Ru(bpy);+
and related complexes have
given evidence for a single ligand localized excited state on the time scale of
molecular vibrations. It was argued that the localized species is present in
solution within a maximum of 1 ns after the excitation [102]. Similar
conclusions were reached by means of resonance Raman spectroscopy of
mixed ligand complexes. It was found that on the time scale of the laser
pulse (18 ns) the excited electron is localized on the ligand which is easier to
reduce [ 3071.
Detailed structural information can be obtained by the TR3 technique.
Indeed high precision determination of an average equilibrium bond length
displacement (of the order of 10 to 30 thousands of an tigstrom
unit)
between the ground and excited states for the bpy ligand in OS and Ru
complexes has been reported [211]. These results are in a very good agreement with those obtained from Franck-Condon
analysis of the vibrational
progression observed in absorption and emission spectra.
Evidence for localization also comes from shifts in absorption spectra as a
function of the solvent polarity, which have been interpreted as due to
instantaneous sensing of the formation
of the dipolar excited state
and
from
excited
state absorption spectra
[M3+O-vyMbw-)12+
[9f%
[99-1011.
As can be seen, the available experimental results indicate that, in fluid
solution and on the time scale of vibration relaxation, the emitting excited
state of Ru(bpy)i+
and related complexes is best described as based on a
single chelate ring localized orbital (Fig. 15(b)). A small amount of interligand interaction provides delocalization of the excitation on longer time
scales. Upper limit value for the rate of transfer of the excitation can be
estimated as follows. According to Foerster 12441 an electronic interaction,
p, can be classified as very strong if the resulting transfer rate, w(t),
between equivalent electronic systems (i.e., ligands) is faster than the rate of
vibrational relaxation. In this case eqn. (96) holds
w(t)
= 4&‘h
(96)
As the rate constant for vibrational relaxation is about 1013 s-l, a v&e of fl
slightly higher than 200 cm-l induces strong coupling behavior. In such a
case, different emission spectra for complexes containing the Ru(bpy)2‘t and
Ru(bpy) : + emitting units should be observed. As the same spectra have
been found for the series of mixed-ligand Ru(bpy),(i-biq) z?, complexes
x ,nm
Fig. 44. Emission spectra in nitriie solution at 84 K of Ru(bpy)z+
and Ru(bpy)(i-biq)$+
(c) [131].
(a), Ru(bpy)2(i-biq)2+
(b),
containing the spectator i-biq ligand (Fig. 44) [131], it must be concluded
that w(t) c 1Ol3 s-l and that thermal equilibrium, i.e. vibrational relaxation
inside the Ru(bpy) unit, is established before the transfer of excitation
occurs.
It is interesting to note that, in the case of strong interaction between
non-equivalent electronic systems (i.e. ligands), the transfer rate is given by
eqn. (97) 12471
w(t)
= (4/3/h)/@
+ A2/4p2)1’2
(97)
where A can be taken as the energy separation between the accepting
orbitals of the two ligands. When A > j3, the transfer rate of excitation is
strongly reduced compared to the case of eqn. (96) for equivalent ligands. It
is therefore expected that complexes of the type Ru(LL) n(LL’) z? n will
exhibit a “weaker” behavior with respect to Ru(LL) $ + or Ru(LL’) <’
complexes.
The nature of the electronic interaction responsible for the interligand
transfer of the excitation is still not well defined. A through bond interaction
requires involvement of metal d orbitals as for the e.i.c. model. A through
space interaction [248] should not be disregarded when large size ligands
145
that exhibit reciprocal steric hindrance (i.e., that ‘touch’
each other) are
present. Thus, it has been suggested that in complexes containing biq and
DMCH ligands the interligand interaction may produce detectable effects
on the emission spectra [ 128,132].
E. COLLECTION
OF SPECTROSCOPIC,
PHYSICAL
DATA
REDOX,
PHOTOCHEMICAL,
AND
PHOTO-
In this Section we have collected data on ground and excited state
properties of Ru(II)-polypyridine
complexes. Table 1 summarizes the spectroscopic and photophysical data, Table 2 the photochemical properties, and
Table 3 the electrochemical data.
Abbreviations and structural formulae of the ligands are shown in the
Appendix. For the sake of convenience, all the polypyridine and polypyridine-like ligands and some other ligands have been numbered. In the Tables,
the first four columns contain these numbers or abbreviations to facilitate a
search based on the coordination sphere. One example of a proper use of the
Tables is as follows. To find the complexes containing the 4,4’-dimethyl2,2’-bipyridine ligand, one should first look at the structural formulae in
Table A2, where number 15 is assigned to this ligand. Scanning the first
columns of the Tables this number is easily found. The abbreviations for
solvents, electrodes, etc., are explained in Table A3. The figures given in the
Tables are usually those reported in the original papers. Such data should be
used with caution because, as in our experience, the experimental errors in
quantum yields, lifetimes, and redox potentials are seldom smaller than 20%,
10% and 10 mV, respectively.
ACKNOWLEDGMENTS
We are deeply indebted to Mr. G. Gubellini for his skill in drawing the
figures. We also thank Mr. V. Cacciari and Mr. Ph. Jolliet for technical
assistance. This work was supported by the Italian National Research
Council and Minister0 della Pubblica Istruzione and by the Swiss National
Science Foundation.
e3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
CN
AN
AN
Cl
Cl
Cl
Cl
Cl
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
Ru(bpyXCN)2,Ru(bpyWCN):R~(~PY)J@):+
Ru@~y)z(AN)t+
Ru(bpy) 2(AN):+
Ru(bpy) 2(ANKI +
Ru(bpy)z(AN)Cf+
Ru(bpy),CL,
RU(~PY),(J,
R~@PY),C~,
RU(~PY),(W,
R@PY),(W,
Ru@py)2(W2
R~(~PY)~(W,
R~@PY),(CN),
RuO2NW2
RU(~PY),W”),
R4bpy)2CW,
W’TY)~@‘~,
Ru(bpy),KN),
WPY)~OO,
RU(~PY),(W,
Ru(bpyI)z(W,
RU(~PY)~P’O,
CN
CN
CN
en
AN
AN
AN
AN
Cl
Cl
Cl
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
H2O
H2O
Hz0
H2O
HClO, 1M
MeOH
90
DMF
DMF
DMF
DMF
CH2C12
MeOH/EtOH
CH,Cl,
MeOH/EtOH
DMF
MeOH/EtOH
MF
AN
AN
CHCl,
H2O
DMF
EtOH
WwWN):-
CN
CN
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
CN
CN
Solvent
Complex
Ligands
(a) Mononuclear complexes
Em.
653
680
683
635
675
652
813
671
602
(RT)
457 (8400)
3.5
620
d
(77 R)
620
0.205
0.69
0.17 a
2.0
2.2
6.X
;77 K)
680
705
752
627
542
610
568
521
722
;,
428
505
505
506 (8350)
431(5900)
445 (9OOfJ)
494
495
538 (9890)
553 (8910)
481
562
457
400
510
426
Abs(t)
0.205
0.22
0.21
0.26
0.254
0.250
0.36
0.40
0.54
0.456
0.22
0.34
0.025
0.101
0.064
- 0.004
(R-D
r
0.020
0.072
0.0068
+
(RT)
222
222
222
317
318
318
318
318
319
97,320
217
321
221
221
322
323
324
325
221
323
326
322
325
321
323
Ref.
Spectroscopic and photophysical data, This Table fists the lowest energy absorption maximum (and its extinction coefficient E) at room temperature, the emission
maximum, the emission lifetime, and the emission quantum yield at 77 K and at room temperature (RT). Lifetime and quantum yield values are for de-aerated solutions
unless otherwise noted. Wavelengths are in nm and lifetimes in cs. Unless otherwise noted, emission occurs from 3MLCT or from an unassigned level (most likely
‘MLCT)
TABLE 1
MPP
MPP
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
CN
CN
CN
CN
CN
1
1
1
1
1
1
ox
ox
NH3
dia
dia
“JH3
co
co
co
co
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
dN
hP
EDP
en
en
en
MPP
MPP
CN
CN
CN
CN
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ru(bpy)z(NH&+
Wbpy) 2(ox)
Wbpy)z(ox)
Ru@p
y):+
Wbpy):+
Wbpy): +
Ubpy): +
Ubpy): +
Wbpy): +
W’PY),(CN),
Wbpy),(CN),
Ru(bpy),KN),
Wbpy),(CN),
R@py),(CN),
Ru(bpy),(CN),
Wbpy),(CN),
Ru(b~y),(W,
Wbpy)z(CN),
R@PY),(CO):+
Ru(bpy),W):+
Wpy)#W2+
R@py)2(dnW2’
Wbpy),(EDP)‘+
Wbpy)2W2+
Ru(bpy)&n)2’
Ru(bpy)2(en)2+
W’JPY),(MPP):+
ck-Wbpy) 2
(MPP):+
Ru(bpy),(MPP):+
trm-Ru@py),
(MPP);+
Ww), VW,
JWmMW,
MeOH/EtOH
MeOH/EtOH
I-decanol
I-octanol
I-pentanol
2-propanol
AC. anh.
AN
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
CH,Cl,
MeOH/EtOH
MeOH
MeOH
M&H
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/H,O
MF
PMM
CH,Cl,
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
648
611
0.0124
0.0222
0.269
0.27
636
451
0.61
0.60
0.71
0.96
3.96
3.8
3.96
4.0
3.9
630
628
610
734
714
547
549
540
443
551
557
518
624
683
584
580
566
592
578
454
454
452
488
429
487
305
461
458
0.850
0.87
0.033
0.070
0.39
0.075
0.056
0.061
0.059
0.038
317
97,320
104
223
223
223
155
223
321
318
210
219 v
221
97
104
107
323
40
323
221
328
318
318
210
210
210
317
97,320
104
318
210
Ru(bpy):+
Ru@PY):+
Ru(bpy):+
Ru@py):+
R~(~PY):+
R@Y):+
R~@PY):+
Ru(bpy);+
Ru(bpy):+
Ru(bpy):+
R~(~PY):+
R~(~PY):+
R~@PY):+
RuOy-d,):+
R~@PY):+
R@PY):+
R@PY):+
R~(~PY):+
Ru(bp
y);+
Ru@py):+
Ru(bpy):+
Ru(bpy): +
R~(~PY):+
Ru(bpy):+
R@PY): +
R~@PY):+
Ru(bpy):+
Ru(bp~):+
Ww):+
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
H2O
eglyc
EPA
EPA
EPA
EtOH
EtOH
EtOH
EtOH
EtOH
glycerol
40
DMF
DMF
DMSO
kg
2:
AN
AN
AN
AN
AN
BN
BzOH
CDSOH
CH,CDOH
CH,OD
Solvent
5.92
3.75
0.746
601
603
588
608
580
450
450
630
611
454
452
446
449
628
619
451
453
.
0.87
0.86
0.92
609
620
609
610
451
454
454
0.926
0.945
0.900
0.79
0.90
0.74
0.68
1.2 c
0.72
0.85
0.76
1.02
0.936
1.00
0.980
1.25
0.93
0.92
0.96
1.10
0.89
;RT)
615
611
580
Em.
(RT)
Em.
(77 K)
452 (13000)
450
Abs (0
0.060
0.052
0.07
0.270
0.130
0.078
0.079
0.068
0.11
0.077
0.070
0.070
0.065
0.086
0.073
0.078
0.059
0.062
+
(RT)
.__-_-I-_.“..,
329
223
126
330
232
223
223
330
223
330
138
322
330
14.6
138
223
232
223
223
331
96
332
332
333
334
223
232
335
336
Ref.
_
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
1
1
1
1
1
1
1
1
1
1
1
1
1
Wbpy): +
Wbpy): +
1
1
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
MeOH/EtOH
HCI 1.5M
HClO, 1M
MeOH
MeOH
MeOH
MeOH
McOH/EtOH
MeOH/EtOH
H2O
H2O
H20
H2O
H2O
H2O
H2O
H2O
Hz0
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
H2O
Ww):+
WJPY):+
Ru(bpy):+
WPY):’
Wbpy): +
R~(~PY): +
R~(~PY):+
WJPY):+
R~PY): +
R~(~PY): +
R@PY): +
R~(~PY): +
WPY): +
WJPY): +
R@PY): +
N%PY):+
wbPY-d,):+
Wpy-dd:+
WFY): +
Wbpy): +
R~(~PY):+
R@PY): +
R@PY): +
WTY): +
R~@PY): +
Wbpy): +
R~@PY): +
WPY): +
Wbpy): +
Wbpy): +,
Wbpy):+
H20
Ww):+
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
450(14300)
453(14650)
449
452
452
452(14000)
453
450
452(14600)
582
581
578
582
5.1
5.2
5.0
5.1
5.21
5.21
5.7
0.328
0.35
0.376
0.376
0.38
630
620
609
627
607
609
628
628
608
607
1.15
0.576
0.580
0.61
0.600
0.63
0.67
0.69
0.69
0.53
0.62
0.765
0.75
0.72
0.72
0.66
0.58
0.60
0.600
0.665
0.685
0.60
0.64
0.65
0.089
0.045
0.053
0.053
0.047
0.042
0.042
0.042
0.042
0.028’
0.055
0.042
217,
329
338
205
342
107
337
111
153
138
149
337
99
332
12
334
223
338
338
322
299
330
146
339
232
138
12
340
321
337
341
223
330
331
104
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
12
11
7
1
1
1
1
1
1
1
1
1
1
OH
1
1
1
Cl
1
1
+
Ru(bpy) 2
(6-tol-bpy)‘+
Ru(bpy) z
(6-sty-bpy)*+
(4-n-bpy)2+
R4w92
(4-Mv)2
R~@PY):+
RuWy):+
R~@PY):+
Ru(bpy):+
Ru(bpy)2
(-bpy)c1+
Ru(bpy),
GbpyPH+
R~@PY)2
Ru(‘wy-ds):’
Ru(bpy-d,):+
Ru(bey-ds):+
R@PY): +
R@PY):+
1
1
1
WW):+
1
1
1
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
acetone
MeOH/
EtOH
acetone
AN
NaHCO,
PY
HCI 1M
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
Me.OH/
EtOH
PC
PC
PC
Solvent
450 (13500)
450 (13800)
493 (11100)
510
454
495
448
450 (14300)
Abs (6)
655
705
680
580
3.1
6.1
Em.
618
616
625
620
622
619
630
630
(RT)
0.78
0.850
0.87
0.92
0.071
0.04
0.071
0.087
0.031 c
0.096
0.089
0.029 ’
345
345
315
344
343
126
229
225
223
343
205
205
138
232
204
205
Ref.
13
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
17
16
16
15
15
15
15
15
13
13
13
13
13
13
13
1
1
13
1
1
Ubpy),
(4,4’-dBr-bpy)‘+
Wbpy),
(4,4’-dCLbpy) *+
R@PY),
(4,4’-dCl-bpy)‘+
Wbpy),
(4,4’-dm-bpy)2+
‘Wbpy),
(4,4’dm-bpy)2 +
Wbpy),
(4,4’-dm-bpy)2 +
Wbpy) 2
(4,4’-dm-bpy)2 +
RU(~PY)Z
(4,4’-dm-bpy)2+
Wbpy),
(3,3’-dm-bpy)2+
W~PY),
(3,3’-dm-bpy)’ +
W~PY),
(3,3’-dm-bpy)2c
W~PY),
(3,3’-dm-bpy)2+
WbpY),
(3,3’-dm-bpy)2+
WJPY),
(3,3’-dm-bpy)2+
Wbpy),
(3,3’-dm-bpy)2+
WJPY),
(3,3’-dm-bpy)2+
W~PY),
(3,3’-dm-bpy)‘+
MeOH/
EtOH
AN
&OH/
EtOH
AN
H2“
H2O
H2O
AN
PY
MeOH/
EtOH
MeOH/
EtOH
MeOH
H2O
H2O
EtOH
AN
AN
450 (14000)
448 (12600)
454
457 (11000)
445 (Mooo)
453 (12600)
448 (11500)
608
586
588
595
2.6
5.2
5.2
5.3
0.35
0.252
647
645
620
- 630
615
630
620
0.42
0.470
0.49
0.63
0.44
0.41
0.39
0.59
0.74
0.025
0.00030’
0.00036
307
344
344
123
299
346
326
307
338
40,
329
338
338
338
338
338
338
329
R@PY) 2
(4,4’-dn-bpy)2+
18
18
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
29
29
Ru(bpyI,
(4,4’-dc-bpy)2+
Ru(bpy),
(4,4’-de-bpy)‘+
Ru(bpy),
(4,4’-dc-bpy)‘+
R~(~PY),
(4,4’-dc-bpy)2 +
29
29
Ru(bpy),
(4,4’-dc-bpy)2+
Ru(bpy)’
(4,4’-dc-bpy)2+
29
29
R~(~PY),
(4,4’-dc-bpy)2+
29
(4,4’-dc-bpy)2+
Ru(bpy),
(4,4’-dph-bpy) 2+
HCI
O.lM
H2O
H2O
H2O
Hz0
H2O
H2O
40
Ru(bp
y)2
29
26
Ru@py),
(4,4’-dph-bpy) 2+
R~(~PY),
(4,4’-dph-bpy) 2+
26
26
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
Ru(bpy),
(4,4’-dph-bpy)* +
M&H/
EtOH
AN
AN
Solvent
26
Ru(bpy),
(4,4’-dn-bpy)‘+
Complex
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
460
457 (19700)
458
514 (10300)
Abs(r)
593
700
(77 K)
Em.
5.6
2.5
;77 K)
0.46
b7K)
686
615
705
686
655
686
630
628
752
(RV
Em.
0.26
0.29
0.50 c
0.46
0.190 csd
0.299
0.32 ’
0.572
1.92
0.006
0.013 c
0.006
0.012
0.041=
0.197
9
(RT)
326 b
339
134
349 b
348 b
130 b
347 b
130b
205
205
123
233
40
40
Ref.
.^---” .._.^^
30
35
35
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
35
35
35
35
34
32
32
32
31
31
31
30
1
1
Wbpy) 2
(Cl2B)*+
Wbpy) 2
(Cl2B)‘+
Wbpy),
(CIZB)2+
Wbpy) 2
(Cl2B)*+
MeOH
H2O
90
CH,OD
CD,OH
AN
bpy)*+
Wbpy),
(c12B)*+
Wbpy),
(C12B)*+
H2O
CHCl,
CHCI,
CHCI,
CHCl,
Wbpy),
(4.4’~DCM-
Wbpy) 2
(4,4’-dst-bpy)*+
Wbpyh
(4,4’-dst-bpy)2+
Wbpy),
(4.4’-dst-bpy)*+
Wbpy),
(4,4/&d-bpy)*+
CHCI,
CHCI,
bpy)*+
WJPY) 2
(4,4’-dnd-bpy)*+
Wbpy) 2
(4,4’-dnd-bpy)‘+
M&H/
EtOH
AN
-bpyj2 +
Wbpy) 2
(4,4’-DTB-
(4,4’-DTB
RWw) 2
415
485
482 (18200)
482
457
458 (13200)
459 (12000)
450 (14500)
590
4.6
663
646
660
665
614
668
620
610
630
625
0.85
0.42
0.61
0.98
0.84
1.26
0.615
0.900
1.17
0.045
0.180
330
330
330
330
330
330
332
351
350
332
351
350
346
329
40,
329
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
57
57
49
48
48
45
43
38
37
Cl
1
1
37
Cl
1
1
36
1
1
iBN/AN
H2O
bpy)2’
Ru(bpyh
(4,4’-DHC-
bpy)2+
Ru(bpy),
(4,4’#-
Ru(bpy) 2
(4,4’-bpy)Cl +
Ru(bpy) 2
@PYC~H)~+
R@PY) 2
(4,4’-bpy)Cl +
0.082 c.d
2.00
0.700
0.37
1.03
;RT)
CH,Cl,/
AN
AN
490 (10800)
698
0.287
632
625
- 720
660
660
615
H2O
H2O
$
(77 K)
0.434 c
476
446
420
480
460
Abs (e)
DMF/
DMF
MeOH
bpy)‘+
R@py),
(4,4’-DCI-
bpy)2+
R~(~PY),
Rst-~PY)12+
Ru(bpy) 2
Wt-~PY)12+
H2O
EtOH
Hz0
CHCI,
Solvent
bpy)‘+
R@PY) 2
(4,4’-DCE-
R~(~PY),
(4,4’-DCE-
Ru(bpy),
(C16B)2+
(C16B)2+
Ru(bw),
1
1
36
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
<lo-j
-0.006c
0.027
0.074
:RT)
358,
359
358
356 b
355
355
348 b
354
353
334
334
352
352
Ref.
61
61
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
62
61
61
59
59
61
59
59
59
59
58
58
58
57
57
1
1
57
1
1
58
58
58
57
57
57
bpym)*+
Ru(bpy),
(bpym12+
Ru(bpyh
(bpW2+
Ru(bpy) 2
(bpym) 2+
Ru(bpy),
(4,4’-dm-
Ru(bpyh(bpz)2+
Ru(bpyh(bp#+
Ru(bpyh
(bpW2+
Ru(bpy),
(bpym)2l
Ru(bpy)Dp@+
Ru(bpy)z(bp#+
Ru(bpy), (bpz) ’ +
Ru(bpy),(bpz)‘+
Ru(bpy),
(4,4’-bpy):+
cis-Ru(bpy),
(m-4,4’-bpy):+
cis-Ru(bpy),
(m-4,4’-bpy):+
cis-Ru(bpy)2
(m-4,4’-bpy):+
Ru(bpy) 2
(4,4’-bpy): l
Ru(bpy) 2
(4,4’-bpy) : +
AN
PC
PC
H2O
AN
AN
AN
AN
MeOH/
EtOH
PC
PC
AN
W-OH
MeOH/
EtOH
AN
MeOH
CH,CI,
442 (10900)
475 f
480 f
420 (10500)
473 (9900)
471 (96cMq
474
450 (23900)
447
639
580
577
3.4
7.59
598
710
710
680
710
710
600
690
686
612,
675 ’
690
680
601
0.08
0.076
0.376
0.38
0.805 =
0.104 c
0.004
0.0036
0.019
0.019
-0.Ooo4”
_ lo-4c
360
225
229
361
227
229
225
360
229
40
233
40
351
357
357
318
357 b
318
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
94
88
88
86
85
82
82
81
68
68
68
68
Ru(bpy),
(4,7-dhy-phen)*+
Ru(bpy),
(4,7-Ph,-phen)*+
Ru@PY)~
(4,7-Ph2-phen)*+
Ru(bpy)z
(4,7-dm-phen)2 +
Ru(bpy) z
(2,9-dm-phen)*+
R@PY) 2
(S-a-phen)*+
R@PY),
(S-a-phen)*+
Ru(bpy) t
tpha)* +
R@PY),
(phW* +
R~PY) 2
tphW*+
R~@PY)2
(5”n-phen)‘+
R@PY),
(phen)*’
Ru(bpy) z
(h-phen)*+
D20
MeOH/
&OH
H2O
MeOH/
EtOH
AN
CH2C1,
AN
Hz“
MeOH/
EtOH
MeOH/
EtOH
“20
IueoH/
EtOH
CH,Cl,
1
1
67
AN
(h-phen)*+
Ru@py
12
1
1
67
Solvent
Complex
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
452 (13600)
452 (15900)
451 (13900)
Abs (r)
Em.
589
583
580
575
585
(77 K)
9.4
5.6
6.6
4.9
;n K)
0.54
0.38
0.44
Em.
652
588
601
612
(RT)
0.800
1.591
1.151
& 0.007
0.684
0.31
;RT)
0.02 c
0.033
9
(RT)
363 b
123
275
123
360
362
362
275
111,
123
210
275
210
40
40
Ref,
99
108
109
109
111
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
111
111
111
111
108
108
108
107
107
107
94
1
1
94
1
1
111
CN
CN
Cl
Cl
WbPY),
(PYm+
WbPy),
@YQ+
WbPy),
@YXCN) +
RGPY),
(PYXCN)+
WbPy),(pY):+
W’JPY)~
(taphen)”
R@PY) 2
(taphen)2’
Ru@PY),
(DIAFO)2+
WbPy),
(DIAF0)2+
WJPY),
(DIAF0)2+
WbPy)2
(DIAF0)2+
R~PY),
(DIAF)2+
R@PY),
(DIAF)‘+
Wbpy),
(DIAF)‘+
Wbpy),
(5,6dm-phexQ2+
WbpY),
(4,7-dhy-phen)2+
W~PY),
(4,7-dhy-phen)*+
acetone
H20
MeOH/
EtOH
AN
MeOH/
EtOH
CH,Cl,
MeOH/
EtOH
MeOH/
EtOH
AN
H20
MeOH/
EtOH
MCOH/
EtOH
AN
H20
MeOH/
EiOH
H20
EtOH
469
505
440 (14@w
440 (14100)
460 (12600)
660
660
574
609
574
577
597
1.8
5.9
4.3
5.9
6.1
3.9
0.23
0.56
0.42
0+27
615
620
788
658
652
0.05
0.137
o.oooo7
0.455
0.004
0.0056
0.0008
0.01=
319
364
364
318
318
238
238
216,
339
216,
339
40
40
216,
339
216.
339
133
123
363 b
363 b
111
111
111
111
111
111
111
111
111
111
111
111
111
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
116
115
111
115
111
1
1
Ligands
115
111
115
111
111
111
111
111
111
111
111
111
111
111
111
111
111
(a) Mononuclearcomplexes
TABLE 1 (continued)
CH,Cl,
CH,CI,
CH,CI 2
eglyc
eglyc
(PY):’
RU(bpYh(PY)22’
Ru(bpy),(py):+
R~(~PY),(PY):+
cis-Ru(bpy),
(PY)Z’
rrnr-Ru( bpy) a
Ru(bpy~z(py):+
Ru(bpy),
(3-I-PY):+
Ru(bpy),
(3-I-PY):+
Ru(bpy),
(3-AEP)2+
Ru(bpy),(py):+
Ru(bpy)z(py):+
Ru(bpyh(py):+
MeOH/
EtOH
CH,Cl,
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
PC
CH,CI,
AN
AN
AN
AN
(PYG’
Ru(bpyh(~~):+
AN
(PYG’
Ru(bpy),(py):+
Ru(bpyh(py)t+
Ru(bpy)z(py):+
iranr-Ru(bpy)2
Solvent
cj~-Wb%
Complex
457
442
454
457
455
455 (8130)
474 (8600)
450 (7900)
Abs(c)
Em.
575
585
589
588
585
581
(77 K)
5.25
10.6
11.4
;77 K)
h7K)
Em.
645
608
609
606
606
(RT)
0.12
0.0027
0.50
0.47
0.500
;Rn
0.0066
2.28 x 1O-4
0.0042
2.33~10-~
:RTI
210
318
126
318
133
318
97,
320
210
251
124
210
318
251
126
364
319
365
365
Ref.
118
119
119
119
119
124
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
144
137
137
137
137
124
124
124
124
124
124
124
116
1
1
144
137
137
137
137
124
124
124
124
124
124
CN
CN
119
119
Cl
Cl
118
W~PY),
(PW&
R@PY),
(PVP)$,
WJPY),
(WP):’
WFY),
(PVP>&
W’PY)~
(PVP&
Wbpyh
(Pm;,
R@pYh(pyd):+
Ru(bpYh(pyd):+
Ru(bpy)dpYd):+
WJPY),
(PVPXCN) +
R@PY)~
v-=tYl-PY):+
Ru(bPY),
(PVP)(CN) +
tYi-PYW+
RUO 2
w=tYl-PY):+
Ru(bwh(Qa~-
tYl-PYv+
Wby)2Wa~
WbpYh(pi&’
(3-AEP)‘+
Ww),
CH2G
CH2Cll
MeOH/
EtOH
MeOH/
EtOH
PC
210
318
210
2.7x10-”
0.31
581(4570)
572
574
319
318
126
0.0020
0.068
126
126
610
440
126
0.0011
364
126
0.0019
364
364
318
318
318
318
366
210
0.0018
0.020
0.020
613
611
611
609
610
460
0.41
0.044
595
5.6
612
460
AN
576
653
592
637
460
460
AN
MeOH/
EtOH
PC
460
469
442
495
AN
H2O
MeOH/
EtOH
AN
MeOH/
EtOH
CH,CI,
CH,Cl,
MEOH/
EtOH
MeOH/
EtOH
Ru(bpy),
(All-ttz); +
153
154
154
153
153
154
154
1
1
1
1
1
1
1
1
1
1
155
Ru(bpyIz
(All-&z); +
152
152
1
1
155
153
151
152
151
I52
1
I
1
1
Ru(bpy),
(Htn);+
Ru(bpy),
(Ph-trz);’
(Ph-trz);+
W’pyl2
Wbpy) 2
(m-t&+
acetone
AN
acetone
AN
acetone
AN
acetone
R@PY), (t=I z
Ru(W9,
147
147
1
1
(m-t&j+
MeOH/
EtOH
MeOH/
EtOH
DMF
147
147
I
CH2C12
I
1
1
Ru(bpy),
147
147
147
1
1
Ru@py)&id)t*
acetone
AN
AN
DMF
CH,CI,
MeOH/
EtOH
CH2Cl2
AN
Solvent
147
145
145
145
145
146
146
145
145
145
145
146
146
1
1
I
1
1
1
1
1
1
1
1
1
(pzXpzH>+
Ru(bpy)z(pzH):+
Ru(bpy)z(pzH):+
Ru(bpy)2(PzH): +
Ru(bpy)z(pzH):+
Ru(bpy),(imid)~+
WW),
Complex
(NW);+
Wbpy)~
(NMI);+
Wm%
(NW);+
Ww),
(NMI);+
145
144
1
1
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
472 (9330)
468 (8710)
473 (8910)
544 (8130)
483
489
470 (5180)
470 (5130)
510 (4890)
Abs(r)
Em.
642
633
628
(77 KI
;77 K)
9
(77 K)
Em.
660
660
645
660
682
661
627
627
122
(RT)
0.31
0.350
i-RT,
0.034
-10-4
10-5
ti
CRT)
319
319
319
319
319
319
319
319
318
210
318
210
319
367
319
319
318
318
367
Ref.
R@PY) 2
(bii~nH~)~+
Wbpy) 2
(~SIIH,)~+
Wbpy) 2
(biimH2)2+
171
173
173
173
176
176
176
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
176
171
171
163
163
160
159
Cl
Cl
1
1
l’s8
Wbpy) 2
(biimH,)‘+
Wbpy) z
(PBzimH)‘*
WbpY) 2
(PBzimH)2t
Wbpy) 2
(PBzimH)2t
Wbpy) 2
(PimH)2+
W~PY) 2
(P~IH)~+
Wbpy) 2
(P~IH)~+
Wbpy) 2
(DPAH)2+
Wbpy) 2
(DPAH)‘+
Wbpy) z
(BPE)Cl+
Wbpy) 2
(BPA)CI+
WbPY) 2
(DPE)”
Wbpy) 2
(DPM)‘+
1
157
1
WbpY) z
(H&z);+
1
155
1
155
1
1
0.11
7.5
MeOH/
EtOH
HClO,
AN
448 (9500)
620
3.25
0.160
622
633
651
0.150
0.262
0.418
0.224
< 10-3
697
625
< 1o-3
707
595
4.240
4.450
0.56
7,2
630
600
596
600
645
605
584
Hz0
AN
473 (9330)
458 (25700)
460 (10500)
453 (7200)
470 (8710)
MeOH/
EtOH
MeOH/
AN
H20
MeOH/
EtOH
Me.OH/
MeOH/
EtOH
AN
AN
AN
CH,Cl,/
CH,Ch/
AN
MeOH/
EtOH
MeOH/
EtOH
AN
368
360
368
360
368 b
368
368
368 b
368
36X
235
358,
359
358,
359
235
366
366
319
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
251
246
246
246
246
246
246
246
245
245
244
244
184
203
203
180
179
179
1
1
2+
Ru(bw)2(biimW
1
1
1
1
176
179
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
Em.
0.038
Em.
640
656
(R-0
H2D
MeOH
McOH/
EtOH
AN
MeOH/
EtOH
AN
MeOH/
EtOH
AN
AN
EtCN
EtQH
MeOH
MeOH/
EtOH
MeOH/
&OH
AN
528 (9410)
480’
476 ’
478 (10800)
445
480 (14600)
483 (10200)
453
495
654
667
658
662
682
2.6
3.5
2.3
1.7
0.898
736
700
687
720
720
671
602
3.000
;77 Ic)
H20
AN
616
(77 K)
640
450 (10800)
463 (11800)
Abs (c)
kOH/
EtOH
MeOH/
&OH/H,0
AN
solvent
0.38
0.32
0.111
0.120
0.092
;Rn
0.029
0.004 c
9
(RT)
329
315
40
233
351
351
274
274
40
40
40
40
370
371
371
369
368 b
368
368
368
Ref.
251
255
235
257
257
257
257
259
259
261
267
270
271
272
273
274
13
13
13
13
13
15
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
13
13
13
13
13
15
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ru(bpy)
(4,4’dm-bpy)$+
Ru(bpy)
(3,3’-dm-bpy)i+
Ru(bpy)
(3,3’-dm-bpy):+
Ru(bpy)
(3,3’dm-bpy)s+
Ru(bpy)
(3,3’dm-bpy):+
RU(~PY)~(BW~+
Ru(bpy)2(W2+
Ru(bpy)2(BW2+
Ru(bpy)2(BL7)2+
Ru(bpy)
(3,3’dm-bpy)t+
Ru(bpy)2(DPJ2+
Ru(bpy)2(dpp)2+
Ru(bpy)2(BL3)*+
Ru(bpy)*(i-biq)‘+
Ru(bpy)2(i-biq)2’
Ru(bpy)2(bi@2’
Ru(bpy)2(bi32’
Ru(bpy)2W32’
Ru@py)2@i@2’
R~@PY),
(OMCH)2’
Ru(bpy) 2
(OMCH)2 +
(DMCH)* +
Ru(Wh
MeOH/
EtOH
MeOH/
EtOH
AN
H20
H20
H20
H20
H20
H2O
AN
H2’=
AN
MeOH/
EtOH
AN
M&H
MeOH/
EtOH
MeOH/
EtOH
AN
nitfile
EtOH
MeOH/
EtOH
AN
449(14000)
454(12300)
453(12200)
448 (15700)
430 (12@00)
525 (8490)
450(11900) f
526 (8710)
527 (8190)
562 (8540)
597
590
586
136
728
742
720
5.4
4.9
4.560
4.090
4.020
4.070
4.7
1.9
1.4
2.6
1.5
0.192
625
610
610
613
610
625
610
675
770
610
742
755
0.356 ’
0.390 =
0.389 ’
0.360 c
0.72
0.135
< 0.060c
1.1
0.27
1.3x
10-5
8x
lo-6c
0.027
0.049
6x
lo-6c
0.052’
0.048’
0.048c
0.048’
4
307
329
338
4
338
338
373
373
373
373
329
131
131
243
103
372
274
344
274
344
40
329
40
26
26
29
30
30
31
43
59
59
59
59
59
61
61
1
1
1
1
1
1
1.
1
1
1
1
1
1
1
61
61
59
59
59
59
61
43
CN
30
30
29
26
26
26
CN
26
1
by):+
Ru(bpyXbpz):+
Ru(bpyWbpz):+
R@YMbp&+
RtipyXbpz):+
Ru@pyXbpz)
(bpym)* +
Ru@pyXbpym):+
RWy)(bpym)?
AN
PC
460’
463 (12000)
46s
iBN/AN
bpyXCN),
Ru(bpy)
(4,4’-DHCAN
AN
PC
PC
PC
502
MeOH/
EtOH
CHCl,
RU@PY)
(4,4’-DTB-bpy)2,+
Ru(bpy)
(4,4’-dnd-
454 (15300)
H2O
465 (14700)
467
AN
MeOH/
EtOH
MeOH/
EtOH
456 (10000)
456
Abs (c)
AN
H2O
Solvent
AN
Ru(bpY)
(4,4’-DTB-bpy);+
R@PY)
(4,4’-dc-bpy);-
Ru(bpy)
(4,4’-dph-bpy);+
Ru(bpy)
(4,4’-dph-bpy);+
R@PY)
(4,4’-dph-bpy):+
R@PY)
(4,4’-dBr-bpy);+
17
1
17
R@PY)
(4,4’-dm-bpy)<+
15
1
15
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
Em.
590
(77 K)
4.8
;77 K)
;7K)
Em.
670
645
654
654
684
644
655
630
635
631
636
631
(RT)
0.182
1.099
1.13
0.70
2.10
1.07
0.54 E
2.12
0.385
k-I
0.011
0.079
0.079
0.049
0.025 =
0.098
0.014
+
(RT)
229
229
225
225
229
233
229
354
40,
329
351
329
134
205
205
233
307
299
Ref.
61
67
67
68
68
68
68
68
68
68
68
81
88
108
108
109
109
111
111
111
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
111
111
111
109
109
108
108
88
81
111
111
111
111
68
68
68
68
61
61
61
NH3
en
en
111
111
111
111
H2O
eglyc
WwXpy),
(NW:+
R@PY)
(py)den)‘+
R@PY)
@Y)2W2’
R@PY)
(taphe&+
RU@PY)
(taphen):+
R@PY)
(DIAFO);+
R@PY)
(DIAFO);+
Ru(bpyX4’l-Ph,phW:+
MeOH/
EtOH
AN
MeOH/
EtOH
AN
AN
H2O
H2O
(phW@y) : +
trons-Ru@py)
(PhaCQy):+
Ru(bpy)(S-n-
pheW:+
eslYC
cis-Rq-hpy)
WWh~:+
h&OH/
WwXpW:+
EtOH
cis-Ru(bpy)(phenXpy):’ AN
AN
mwRu(bpy)
Ru(bpyxPh@:+
RGpyXphed:+
Ru(bpyXphed+
AN
MeOH/
EtOH
AN
Wbpyxbpym):+ IJC
Ru(bpy)(h-phen);+
Ru(bpy)(h-phen):’
476 (4000)
438 (13200)
446 (11300)
448 (9600)
476 (11000)
442 (18000)
450 (14800)
625
581
650
573
588
578
569
575
585
10.9
2.0
5.2
8.0
14.8
9.1
15.8
4.9
0.56
750
670
612
0.13
2.646
$0.007
0.784
0.18
0.012
0.011
251
251
365
238
238
40
40
275
275
251
251
365
251
275
111,
123
365
365
225
40
40
111
111
112
112
163
163
180
181
181
184
246
246
246
246
1
1
1
1
1
1
1
1
1
1
1
1
1
1
181
181
184
246
246
246
246
180
163
112
112
163
281
111
111
113
H2D
Hz0
AN
EtCN
EtOH
MeOH
WwXW):+
WWYXP@:+
Ru(bp~xpq):+
W’WYXP&+
CHICI,
Ru(~PYX~PY):+
Ru(bpYwPY)2,+
475
480 (11100)
458
479
517 (11600)
435 (12200)
458 (5400)
eslyc
AN
MeOH/
EtOH
AN
478 (6500)
468
455 (5500)
465 (6000)
457 (5500)
Abs (t)
AN
AN
eslyc
AN
eglyc
AN
eglyc
Solvent
WwXAzpy):+
R@PY)
@ydipy)?
(DPAH);+
WJPY)
R~@PY)
@YXtrpY12+
RU(~PYXPMA):+
Ru(bpyKPM&+
R@PY)
(DPAH);+
RU@PYMPY)Z
(2-AEP)2+
R@PYMPY)2
(ZAEP)*+
111
1
113
Ru(bpyxPy),
(PMA)z+
112
111
1
111
Ru(bpyx~~):+
RuOsCl+
Ru(bpyxpy):+
Ru(bpyxpy),
(PM.A)z+
111
111
111
112
111
111
111
111
1
1
1
1
111
111
111
111
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 1 (continued)
829 g
625
616
700
581
581
581
585
9.0
11.3
10.6
10.5
10.9
Em.
854
670
685
718
604
636
(RV
0.30
0.028
< 0.001 c
375
376
370
233
351
351
274
369
235
365
251
235
374
251
365
251
365
251
251
365
Ref.
251
257
257
257
251
251
251
257
251
251
259
259
281
281
281
281
281
281
281
281
281
281
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
NH,
MPZ
CN
CN
CN
CN
CN
CN
Cl
259
259
Cl
257
251
246
1
Ru(bpyXtrpy)
(NHd2+
(CN)+
Ru(bpyXtrpy)
(MPz)2’
Ru(bpyXtrp y)
R@pyXtrpy)
(w+
RutbpyXtrpy)
VW+
Ru(b~yXtrpy)
VW+
Ru@pyXtrpy)
w)+
.Ru(bpyXtrpy)
(CN)+
RulbpyXtrpy)
Cl+
Ru@pyXtrpy)
a+
Ru(bpyXi-biq);’
Ru(bpyXi-biq)it
Ru(bpyxbi&+
Ru@pyxbh%
Ru(bpyXbi#
R@PY)
(DMCH);+
Ru(bPY)
(DMCH);+
487 (9950)
DMF
AN
H2O
MeOH/
EtOH
MF
462 (8800)
480
472
484
CHCI,
MeOH
487 (9950)
506 (7800)
450 (11600) f
547 (8550)
546 (7250)
559 (9640)
MeOH/
EtOH
AN
AN
Ilit&
Me.OH/
EtOH
AN
MeOH
M&H/
EtOH
MeOH/
EtOH
AN
MeOH/
EtOH
AN
626
639
692
4.6
5.1
5.3
2.4
5.0
2.1
741
586
1.8
1.9
3.1
133
737
666
608
654
664
666
657
664
729
615
742
742
1.0
0.20
0.39
3.8 x
lo-’
221
c 0.001
321
377
221
40
221
0.001
c o.cm
221
221
4
40
131
131
40
214
329
344
274
344
40,
329
214
281
281
281
2
2
3
3
4
4
5
5
6
6
1
1
1
2
2
3
3
4
4
5
5
6
6
Ligands
6
6
5
5
4
4
3
3
2
2
156
NH,
NH,
(a) Mononuclear complexes
TABLE 1 (continued)
Ru(Qmo-bpy):+
Ru(Cmo-bpy) : +
Ru(4dma-bpy)g +
Ru(4-dma-bpy):+
Ru(4-a-bpy):+
Ru(Ca-bpy):’
Ru(4-Br-bpy);+
R+Br-bpy);+
Ru(bp~Mtrpy)
oJHj)2+
Ru@pyKtrpy)
(NHJ)~+
RuOyNrpy)
P-Q2+
Ru(4-0bp y); +
Complex
MeOH,’
EtOH
MeOH/
EtOH
MeOH,’
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH,’
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
Hz0
HCIO,
1M
glycerol
Solvent
461 (14100)
475 (15000)
472 (12100)
457 (14000)
454 (13500)
450
Abs (c)
+
(77 K)
Em.
660
680
675
640
640
608
(RT)
0.67
0.35
0.35
0.82
0.67
0.480
0.43
0.014 =
0.039
0.006 c
0,023
0.006 c
0.021
0.018 =
0.052
0.014 =
0.030
o.OiuI5
_____._l,ll”.
_- .~._.__.
205
205
205
205
205
205
205
205
205
205
377
321
335
Ref.
7
7
8
8
9
9
10
10
13
13
13
13
13
13
13
68
68
68
8
8
9
9
10
10
13
13
13
13
13
13
13
13
13
13
7
7
+
Me.OH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
AN
H2O
(phen) i ’
Ru(3,3’-dm-bpy)
68
68
68
68
(phen):’
(phen)?
Ru(3,3’-dm-bpy)
H2O
Ru(3,3’-dm-bpy),
(phen)”
Ru( 3,3’-dm-bpy) 2
(phen)2+
Ru(3,3’-dm-bpy),
(phen)2c
Ru(3,3’-dm-bpy)
68
68
Ru(3,3’-dm-bpy):’
MeOH/
EtOH
MeOH/
EtOH
H2O
H2O
MeOH/
EtOH
MeOH,’
EtOH
H2O
13
MeOH/
EtOH
MeOH
MeOH/
EtOH
AN
Ru(3,3’-dm-bpy):’
Ru(3,3’-dm-bpy):’
Ru(3,3’-dm-bpy):’
Ru(6-m-bpy):+
Ru(L-m-bpy):+
Ru(4-tep-bpy)$+
Ru(4-tep_bpy):tH2O
Ru(4-bebpy);+
Ru+bo-bpy);
Ru(4-n-bpy):+
Ru(4-n-bpy);+
13
13
13
10
10
9
9
8
8
7
7
450 (15200)
451(14ooo)
456 (10800)
456 (11600)
448 (llooo)
466 (18300)
460 (14800)
480 (20400)
576
9.4
9.3
6.4
601
591
6.4
4.1
3.8
595
585
628
643
0.422
0.281
0.113
0.0968
611
625
638
650
700
205
0.017 c
0.21
4.0 x
10-5
4.6 x
lo-SC
328
5~10-~’
338
338
338
338
338
6xW6
40,
329
338
329
338
379
379
378
378
205
0.053
0.60
0.760
344
344
0.12
14
15
15
IS
15
IS
15
15
15
15
IS
15
15
15
15
15
15
IS
15
15
15
15
15
14
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
I5
15
15
15
15
Ligands
15
17
15
15
15
14
15
15
1s
15
15
1s
15
15
15
15
15
15
15
15
15
15
15
(a) Mononuclearcomplexes
TABLE 1 (continued)
Ru(4,4’-dm-bpy):+
Ru(4,4’dm-bpy) z
(4,4’dBr-bpy)* +
Ru(4,4’dm-bpy):’
Ru(4,4’-dm-bpy):’
Ru(4,4’-dm-bpy)i+
MeOH/
EtOH
&OH/
EtOH
MeOH/
EtOH
I&OH/
EtOH
NaLS
AN
H2O
H2’3
W’
H2O
H2O
Hz0
Hz0
H20
H2O
H2O
EtOH
gIycero1
40
455 (13000)
455 (17000)
459
459 (14900)
450
460 (14300)
505
450 (17000)
458
459
AN
AN
AN
Ru(3,3’-DCI-bpy):’
Ru(4,4’-dm-bpy):+
Ru(4,4’-dm-bpy):+
Ru(4,4’-dm-bpy); +
Ru(4,4’&bpy);+
Ru(4,4’-dm-bpy);+
Ru(4,4’-dm-bpy); +
Ru(4,4’-dm-bpy)f +
Ru(4,4’-dm-bpy);+
Ru(4,4’-dm-bpy)i+
Ru(4,4’-dm-bpy):+
Ru(4,4’-dm-bpy)g +
Ru(4,4’-dm-bpy);+
Ru(4,4’-dm-bpy);+
Ru(4,4’-dm-bpy):+
Ru(4,4’-dm-bpy):+
Ru(4,4’-dm-bpy):+
Ru(4,4’-dm-bpy);+
CH2Q2
Abs (c)
Solvent
Complex
Em.
593
593
593
(77 IQ
4.6
;77 K)
0.283
Em.
661
640
631
642
589
628
590
670
618
634
618
(RT)
0.56
0.95
0.342
0.34
0.335
0.35
0.33
0.33
0.330
0.90 =
0.931
0.607
0.086
0.027 ’
0.014
0.026
0.021 c
0.12
:RT)
382
307
204,
205
232
205
380
307
232
135
322
333
335
336
149
12
101
338
338
322
381
299
232
338
Ref.
5
0
15
15
15
15
17
37
16
16
16
16
17
17
17
18
18
19
19
20
20
20
15
15
15
15
15
15
16
16
16
16
17
17
17
18
18
19
19
20
20
20
20
20
20
19
19
18
18
17
17
17
16
16
16
16
37
17
94
94
94
37
Ru(4,4’-ds-bpy)jRu(4,4’&-bpy);Ru(4,4’-ds-bpy)j-
Ru(4,4’da-bpy):+
Ru(4,4’-da-bpy):+
Ru(4,4’-dn-bpy):+
Ru(4,4’-dn-bpy):+
Ru(4,4’-dBr-bpy);+
Ru(4,4’-dBr-bpy):+
Ru(4,4’dBr-bpy): +
Ru(4,4’-dCl-bpy);+
Ru(4,4’-dCl-bpy):+
Ru(4,4’-dm-bpy)z
(4,4’-DCE-bpy)*+
Ru(4,4’-dm-bpy)l
(4,7&y-phen)*+
Ru(4,4’-dm-bpy),
(4,7-dhy-phen)*+
Ru(4,4’:dm-bpy)z
(4,7dhy-phcn)*+
Ru(4,4’-dm-bpy)
(4,4’dBr-bpy):+
Ru(lY-dm-bpy)
(4,4’-DCE-bpy):+
Ru(4,4’dCLbpy): +
Ru(4,4’-dCl-bpy);+
40
Hz0
MeOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
AN
MeOH/
EtOH
MeOH/
EtOH
MeOH,’
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
AN
CH,Cl,
AN
H2O
EtOH
40
CH,Cl,
504 (10500)
473
465 (17300)
456 (19000)
665 (15500)
462 (17000)
483
452 (llOt!O)
460 (13550)
493
600
632
595
642
2.9
10.50
0.15
705
700
660
624
670
632
658
647
658
658
695
0.99 c
0.48 ’
0.87 ’
0.10
0.25
0.52
0.40
0.48
1.415
0.340
0.610
0.853
0.004
0.002 c
0.001 c
0.02
0.060
0.028 ’
0.020 c
0.036
0.10
0.01 c
0.02 =
0.07
204,
205
134
134
134
205
205
204,
205
205
307
205
205
205
344
344
135
307
363 b
363 b
363 b
135
22
22
22
22
22
23
Ru(4,4’-DEO-bpy);+
Ru(4,4’-DEO-bpy);+
Ru(4,4’-DPO-bpy); +
Ru(4,4’-DBO-bpy); +
Ru(4,4’-DBO-bpy):+
23
23
24
24
25
25
26
26
26
26
23
23
24
24
25
25
26
26
26
26
26
26
26
23
24
24
25
25
26
26
26
26
26
26
26
Ru(4,4’-dph-bpy)$+
Ru(4,4’-dph-bpy):+
Ru(4,4’-dph-bpy);+
26
26
26
Ru(4,4’-dph-bpy);+
Ru(4,4’-dph-bpy);+
Ru(4,4’-dph-bpy);+
Ru(4,4’-dph-bpy);+
Ru(4,4’-DPO-bpy);’
Ru(4,4’-BAA-bpy); +
22
Ru(4,4’-BAA-bpy):+
Ru(4,4’-DEA-bpy);+
21
21
21
21
21
Ru(4,4’-DEA-bpy);+
Complex
21
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
HZ0
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
AN
MeOH/
EiOH
MeOH,’
EtOH
MeOH/
EtOH
MeOH,’
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
Solvent
473 (28ooo)
474
474 (32700)
476 (13500)
479 (13400)
477 (13oLq
479 (15Ooo)
518 (14500)
Abs (c)
Em.
610
(77 K)
4.9
4.68
;77 K)
0.57
0.573
@
(77 K)
635
638
632
670
670
675
670
(RT)
Em.
1.95
0.67
0.31
0.35
0.30
0.41
0.13
:RT)
0.306
0.058 ’
0.015 c
0.032
0.018 c
0.038
0.020
0.009 c
0.014 c
204,
205
205
107
383
233
149
342
205
205
205
204,
205
205
205
205
205
205
0.005 c
0.027
205
Ref.
0.010
4
(RT)
.-I.._^ _.-.
28
28
29
31
31
31
30
30
34
37
37
37
38
39
28
28
29
29
29
29
30
30
33
34
31
37
37
38
38
39
28
28
29
29
29
29
30
30
31
34
37
37
37
38
38
39
38
33
21
21
27
27
27
27
CH,Cl,
bpy):+
Ru(4,4’-DCE-
AN
bpy):+
Ru(4,4’-DCC-
bpy):+
AN
bpy):+
Ru(4,4’-DCI-
bpY):+
Ru(4,4’-DCI-
bpy):+
Ru(4,4’-DCE-
M&H/
EtOH
MeOH/
EtOH
AN
H2O
bpy):+
Ru(4,4’-DCE-
H20
(4,4’-poeg-bpy):+
Ru(4,4’-DCM-
468
464 (23300)
467
455 (7000)
456 (16800)
484
AN
MeOH/
EtOH
478 (13000)
THF
H,O/THF
487 (33000)
460 (16100)
H,O/
CHCI,
H2O
MeOH/
EtOH
M&H/
EtOH
M&H/
EtOH
MeOH/
EtOH
Ru(4,4’-dnd-bpy)
Ru(4,4’-dc_bpy)$Ru(4,4’-dc-bpy),
(4,4’-dnd-bpy)2 +
Ru(4,4’dc-bpy)2
(4,4’-dnd-bpy)2+
Ru(4,4’dc-bpy),
(4,4’-dnd-bpy)2 +
Ru(4,4’-DTB-bpy); +
Ru(4,4’-DTB-bpy);+
Ru(4,4’dsty-bpy): +
Ru(4,4’-dsty-bpy): +
Ru(4,4’-dbz-bpy):+
Ru(4,4’dbz-bpy);+
607
575
5.3
205
205
0.030
0.009 c
630
625
629
655
629
2.21
2.39
1.65
2.230
0.89 c
0.43
0.200
0.076 ’
0.30
354
380
204,
205
354
205
135
134
40,
329
384
329
346b
625
0.008
205
0.030 =
134
346
205
0.098
351 b
1.15
0.62 ’
0.72
1.25
660
643
677
680
640
40
41
42
43
50
50
51
51
52
52
54
54
59
59
59
59
59
59
40
41
42
43
50
50
51
51
52
52
54
54
59
59
59
59
59
59
Ligands
AN
AN
bpy):+
Ru(4,4’-DCNE-
bpy):+
Ru(4,4’-DCNY-
59
59
59
59
59
59
54
54
52
Ru(bpz) : +
Ru(bpz):+
Ru(bpz);+
bpy):+
Ru(bpz);+
Ru(bpz):+
Ru(bpz);+
bw):+
Ru(6,6’-dm-
bpy):+
Ru(6,6’-dm-
bpy):+
Ru(S,S’-BAA-
52
bw): +
Ru(5,5’-DCE-
bpy): +
Ru(5,5’-BAA-
51
51
50
bpy): +
Ru(5,5’-DCE-
bw):+
Ru(5,5’-dm-
50
MeOH/
EtOH
AN
AN
AN
AN
AN
AN
iBN/
AN
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH,’
EtOH
MeOH
AN
Ru(4,4’-DCB-
bpy):+
Ru(4,4’-DHC-
Solvent
Complex
bw):+
Ru(5,5’-dm-
43
42
41
40
(a) Mononuclearcomplexes
TABLE 1 (continued)
443 (15100)
435
440 (13000)
443
439
440
446 (7440)
445 (14900)
495 (9900)
440 (14700)
Abs (c)
589
(77 K)
Em.
2.5
;77 K)
0.0176
;7K)
591
627
603
585
630
720
620
638
632
631
636
0.740
0.72
2.40
0.23
0.35
2.14
2.21
2.19
1.93
0.024
0.021 c
0.126
0.004
0.003 c
0.015 =
0.037
382
386
229
387 b
232
233
379
379
205
204,
205
205
205
205
205
354
354
354
354
Ref.
59
59
59
59
59
59
59
59
59
59
59
59
61
61
61
61
61
61
61
61
61
62
62
63
63
59
59
59
59
59
59
59
59
59
59
59
59
59
61
61
61
61
61
61
61
61
62
62
63
63
63
63
62
61
61
62
61
61
61
61
61
61
61
59
59
61
59
59
59
59
59
59
59
59
59
bpym):+
bpW:+
Ru(6,6’-dm-
bpym):+
Ru(6,6’dm-
bpym):+
Ru(4,4’-dm-
Ru(bpym):+
Ru(bpym):+
Ru(4,4’dm-
(bPym):+
Ru(bpYm): +
Ru@pym):+
Ru(bpym):+
Ru(b~ym)i+
R@pym)i+
Ru(bpym): +
Ru(bpz): +
R@Pz): +
Ru(bpz),
(bpym?’
Ru(bpz)
Ru(bpz):+
Ru@Pz):+
Ru(bpz)f+
R@P~):+
Ru@Pz):+
R~@Pz): +
Ru@pz): +
Ru(bpz):+
Ru(bpz);+
MeOH/
EtOH
H20
MeOH/
EtOH
MeOH/
EtOH
PC
PC
AN
H2’3
H2O
H2O
AN
AN
503 (10700)
449
662
662
588
705
639
639
725
635
644
639
0.131
0.12
0.064
0.19
0.06
0.011
0.011
0.09
0.002
0.077
0.95
655
PC
0.043
0.075
0.11
0.060
0.074
0.074
0.074
0.84
1.1
0.76
1.04
0.90 c
0.920
0.75
0.94
0.795
0.82
1.06
573
603
595
595
603
Bi)5
610
610
633
454 (8600)
450
452 (7400)
441
443 (15000)
442
MeOH/
EtOH
PC
PC
PC
H2O
H2O
H2O
H2O
H2O
AN
DMF
EtOH
241
241
232
229
225
232
229
232
361
390
232
232
225
229
225
225
388
232
232
389
278
387 b
390
232
232
64
64
64
64
64
65
65
65
65
65
65
66
66
66
66
66
61
67
64
65
65
65
65
65
65
66
66
66
66
66
67
67
Ruth-phen):+
Ru(h-phen)$*
Ru(Cpy-prim): +
66
61
67
Ru(6-py-prim): +
Ru&py-prim):+
Ru(6-py-prim):+
Ru(Cpy-prim): +
Ru(Cpy-prim):+
Ru(+py-prim):+
Ru(+py-prim): +
Ru(4-py-prim): +
Ru(4-py-prim):+
Ru(4-py-prim): ’
Ru(bprid); +
66
66
66
66
65
65
65
65
65
65
64
64
64
Ru(bprid) ; +
Ru(bprid): +
Ru(bprid) : +
Ru(bprid) : +
Ru(bprid);+
Ru(bprid) ; +
Ru(bprid); +
64
64
64
64
64
64
64
64
64
64
64
64
64
64
64
Complex
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
Hz0
Hz0
MeOH/
EtOH
MeOH/
EtOH
AN
MeOH/
EtOH
MeOH/
EtOH
AN
H2O
HZ0
MeOH/
EtOH
MeOH/
EtOH
AN
DMF
EtOH
H2’3
H2O
H2O
AN
DMF
EtOH
Solvent
453 (14700)
476
452 (10200)
451
582
625
589
594
601
610
670
633
634
636
622
5.5
Em.
(RT)
444 (11500)
@
i77 K)
652
601
7
(77 K)
Em.
(77 K)
449
Abs(c)
7
0.190
0.11
0.22
0.41
0.45
0.37
1.0
0.89
0.95
0.700
0.58
0.59
(RT)
0.012
0.017
0.012
0.008
0.0070
0.014
0.028
0.059
0.048
0.055
9
(RT)
40
40
232
232
241
232
241
232
232
232
390
232
232
232
232
232
232
241
390
232
241
Ref.
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
en
68
68
68
68
68
68
68
68
68
68
68
68
Ru(ph~),OJ),
Wphen)2092
CN
CN
CN
68
68
68
68
68
68
68
68
68
68
68
68
Ru(phed+
Ru(phen):+
Ru(phen):’
Ru(phen):’
Ru(phen)$+
Ru(phen)i+
Ru(phen):+
Ru(phen)z+
Ru(phen):+
Ru(phen)$+
Ru(phen):+
Ru(phen): +
Rubhen) 2
(NH,):+
Ru(phen),(W
ox
Ru(phen)2(en)2+
2
NH,
2 (W
en
RuWW
2
NH3
CN
CN
‘WphW,(CN)
Ru@heM2002
WphN2(~)2
en
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
Ru(phen)(en):+
Rubhen),(
Ru(phen)2(CN) 2
Ru@he@,(CN),
CN
CN
CN
CN
CN
CN
CN
en
H2O
H2O
40
DMF
EPA
EtOH
2:
AN
AN
CH,Cl,
MeOH/
EtOH
450
447 (19000)
447
477 (WOO)
442
478
477
431
565
608
702
702
759
570
H2O
HZ0
MeOH/
562
584
716
567
448 (10400)
421 (9500)
469
MeOH
MeOH
I&OH
MeOH/
EtOH
MeOH/
H2O
H2O
DMF
EtOH
40
9.93
5.1
577
593
1.080
604
638
605
626
0.92
0.29
0.68
0.870
0.50
0.46
0.15
1.09
1.1
0.250
0.144
0.71
0.654
1.58
1.58
0.154
0.825
1.09
0.019
146
0.063
0.028
232
331
232
336
149
317
321
232
124
322
392
97
317
317
219
323
317
322
323
391
323
322
323
327
219 b
323
Ru(phen):+
Ru@hen);+
Rubhen); +
Ru(phen):+
Rutphm):+
Ru(phen):+
Ru(phen);+
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
Ru(phen);+
68
68
68
Ru(pheN:+
Ru(phen)$+
Rubhen):+
Ru(phen):+
Ru(pb):+
Ru(ph):+
Ru(phN: +
Ru@haQ; +
Ru(pben):+
RIl(pkll);+
Ru@hen):+
Ru(phen):+
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
Ru(phen): +
Complex
68
68
68
68
68
68
68
68
68
68
68
68
68
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
1.5 M
Ha’&
1M
MeOH
MeOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH,’
EtOH
MeOH/
EtOH
Ha,
H2O
H2O
Hz0
H2O
H2O
H2O
Hz0
H2O
Hz0
Hz0
Hz0
Hz0
Solvent
446WOt-w
447 (18100)
Abs (I)
Em.
589
567
565
(77 K)
9.8
9.8
9.79
9.79
;77 K)
0.600
0.58
0.584
0.584
4
(77 K)
Em.
603
604
(RT)
0.313
0.81
0.921
0.908
1.11
0.%2
0.459 c
0.960
O.%
0.72
1.08
0.92
1.06
0.072
0.058
0.032 ’
“^_I
._.._
- _“~_^..
111,
123
379
337
342
337
379
104
321
337
12
393
338
338
275
322
381
392
394
146
232
340
Ref.
Ru(phen):+
Ru(phW:+
Ru(phen)2+
(5-CI-phen)2+
Ru(phen) 2
(5-Br-phen)2+
68
68
79
80
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
Ru(phen),
(4,7-dsph-phen)
Ru(phen)l
(4,7&ph-phen)
92
Ru(phen),
(4,%dsph-phen)
Ru(phe%
(4,7-Ph2-phen)2+
Ru(pheQ,
(4,7-Ph,-phen)2+
Ru(phW,
(4,7-Ph,-phen)2+
Ru(phe+
(4,7-dm-phen)‘+
Ru(phe@2
(4,7-dm-phen)*+
Ru(phen),
(5-Ph-phen)2C
Ru(phen):+
Ru(pW:+
92
92
88
88
88
86
86
84
68
68
Ru(phen);+
68
68
68
Ru(phen)f+
68
68
68
68
H2O
H2O
40
MeOH
H2O
“20
H2O
40
H2O
MCOH
MeOH/
EtOH
MeOH/
EtOH
&OH/
EtOH
MeOH/
&OH
NaLS
PMM
MeOH
445 (ZOocq
447
9.9
566
513
564
10.1
565
0.578
611
595
394
392
392
322
322
327
322
322
394
0.488 ’
1.94
1.389
4.22
3.07
2.56
5.25
3.46
0.920 =
382
109
327
204,
206
232
327
0.019
0.989
0.947
1.82
0.45
338
268
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
Ligands
257
257
257
257
251
251
246
Ru(phen)*(biq)*’
Ru@h@,
(DMCH)*+
Ru(pherQ2(biq)*’
Ru(phcn)2(biq)2’
Ru(phen)z(biq)2’
Ru(ph&
(DMCH)*+
Ru(phm)~(~~*+
Ru@hwX~@~+
Ru@henMti*+
RU@be%(W*+
Ru@hen),
(BDCMPH2)*+
106
246
246
246
Ru@he&
(BDCMP)
Ru@he&
(4,7dhr_phen)*’
Ru@bW,
(4,7-dhy-phen)”
Ru@he@,
(4,7dhy-phen)*’
MeOH/
EtOH
AN
MeOH
MeOH/
EtOH
MeOH/
EtOH
AN
I&OH
MeOH/
EtOH
MeOH/
EtOH
AN
HCl12M
AN
H2O
EtOH
40
MeOH
Ru@hen),
(q’l-dsph-phen)
Solvent
Complex
105
94
94
94
92
(a) Mononuclear complexes
TABLE 1 (continued)
522 (9300)
523 (9480)
522 (10600)
483 (9200)
476 ’
465 (10700) f
463 (43600)
455 (15000)
Abs(c)
Em.
711
729
710
653
664
590
(77 K)
1.8
2.1
2.0
3.1
3.8
3.0
;n K)
0.38
;7K)
741
728
690
632
610
635
635
1.4
1.25
2.10
3.98
0.04’
0.07 c
315
40
274
274
315
40
315
40
274
274
395 b
395 b
363 b
383 b
363 b
327
Ref.
. ^.____.
68
84
86
86
246
246
257
257
69
69
72
73
74
75
76
77
78
68
68
68
68
68
68
68
68
68
69
72
73
74
75
76
77
78
78
77
Ru+MoPh-phcn):+
Ru(&BrPh-phen);+
Ru(dbph-phen):’
RuQLtol-phen);+
75
76
Ru(QPh-phen);+
Ru(4-m-phen):+
Ru(Zm-phen):’
Ru(2-m-phen):+
Ru(phen)(biq):+
Ru(phen)@k$
Ru@he@oW+
Ru@he@W:”
Ru@he@
(4,7dm-phen):+
MeOH
MeOH/
EtOH
MeOH
MeOH/
EtOH
MaOH
&OH/
EtOH
MeOH/
EtOH
M&H/
EtOH
MeOH/
EtOH
MeOH/
EtOH
M&H,/
EtOH
MeOH/
EtOH
MeOH/
EtOH
Hz0
40
HZ0
(9-PDP)3+
Ru(phen)
(5-Ph-phen):+
Ru(phen)
(4,7dm-phen)i+
AN
Ru@hMz
74
73
72
69
69
257
257
246
246
86
86
84
262
0.80
4.00
3.50
4.9
4.1
3.25
602
605
605
612
615
615
44s (22000)
450 (22100)
453 (23600)
454 (28700)
452 (25300)
452 (25300)
0.172
1.78
5.9
2.3
3.8
0.130
0.136
0.184
0.117
206
206
206
206
206
206
0.054
0,109
206
0.037
379
379
274
274
274
274
392
392
2.201
1.243
394
395
0.770 c
0.53
630
576
738
675
643
600
450 (18100)
446 ww
551 (8690)
480 f
440 (19ooo) f
Ru(S-Cl-phen);+
Ru(S-Cl-phen):+
Ru(S-Br-p&n):+
Ru(S-Br-phen):+
Ru(S-Br-phen):+
Ru(S-Br-phen):+
Ru(S-Br-phen)$+
Ru(S-Br-phen): ’
Ru(S-n-phen)$+
Ru(S-n-phen):+
Ru(5-n-phcn):+
Ru(S-n-phen)!+
Ru(S-m-phen):+
Ru(S-m-phen)$+
Ru(S-m-phen):’
Ru(S-m-phen)i+
Ru(S-m-phen):’
Ru(S-m-phen)s+
Ru(S-m-phen):+
79
79
80
80
80
80
80
80
81
81
81
81
83
83
83
83
83
83
83
79
79
80
80
80
80
80
80
81
81
81
81
83
83
83
83
83
83
83
79
79
80
80
80
80
80
80
81
81
81
81
83
83
83
83
83
83
83
40
H2O
H2O
H2O
Hz0
H20
D20
2:
H2O
H2O
H2O
NaLS
H2O
H2O
H2O
H2’3
D20
HCl,
1.5 M
M&H/
EtOH
NaLS
H2O
H2O
H2O
H2O
H2O
glY=J'
Ru(S-Cl-phen):+
Ru(S-Cl-phen):+
Ru(S-Cl-phen):’
Ru(S-Cl-phen);+
Ru(S-Cl-phen):+
Ru(S-Cl-phen)$+
Ru(S-Cl-phen):+
Ru(S-Cl-phen):+
79
79
79
79
79
79
79
79
79
79
79
79
79
79
79
79
Solvent
Complex
79
79
79
79
79
79
79
79
Ligauds
(a) Mononuclear complexes
TABLE 1 (continued)
450
450 (19400)
449
449 (ZCQOO)
448 (18800)
446 (17900)
447
447 (18400)
Abs (c)
Em.
(77 K)
;77 K)
c
(77 K)
Em.
575
597
606
- 595
593
604
605
593
(RT)
1.33
1.33
1.330
1.33
i 0.005
1.71
2.71
2.08
1.50
1.04
0*94
1.21
1.25
2.16
c 0.005
< 0.005
382
322
149
393
322
381
382
149
12
101
275
322
392
336
149
12
101
322
206
0.67
0.035
101
322
381
340
322
335
149
12
Ref.
1.09
3.0 c
0.94
0.94
0.94
0.%2
1.23
0.72
+
(RT)
85
85
86
86
86
86
85
85
86
86
86
86
86
86
86
86
s6
86
86
86
86
86
86
86
85
85
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
86
83
84
84
84
a4
83
84
84
84
84
83
84
84
84
84
83
83
83
83
83
83
83
83
83
83
83
83
Ru(4,Fdkphen)i+
Ru(4.7-dm-phen); +
Ru(4,7-dm-phen):’
Ru(4,7-dm-phen):+
Ru(B’I-dm-phen)j+
Ru(4,f-dm-phen):’
Ru(4,7-dm-phen): ’
Ru(4,7-dm-phen) ; +
Ru(4,7-drn-phen); +
Ru(4,Zdm-phen):’
Ru(4,7-dm-phen);’
Ru(4,7-dm-phen): *
Ru(4,7dm-phen); +
Ru(4,7-dm-phcn); +
Ru(4,7-dm-phen); +
Ru(4,7-dm-phen): +
Ru(2,9-dm-phen):’
Ru(2,9-dm-phen) f’
Ru(S-m-phen):+
Ru(S-Ph-phen);+
Ru(S-Ph-phen);+
Ru(S-Ph-phen):+
Ru(S-Ph-phen)$+
Ru(S-m-phet@
Ru(S-m-phcn):+
Ru(S-m-phen)z+
Ru(S-m-phen);+
1.5 M
MeOH
MeOH/
EtOH
MeOH/
EtOH
NaLS
PMM
Ha,
I-40
H20
H2O
H2O
448 (22700)
600
612
613
445
0.65
0.0479
H2O
2.3
607
615
588
597
595
597
445 (25300)
501 (2580)
448 (21700)
448 (24600)
445 (21Ocq
607
40
Hz0
Hz0
2:
M&H/
EtOH
MeOH
M&H/
EtOH
H2O
H2O
40
MeOH/
EtOH
NaLS
H2O
Hz0
H2O
3.30
0.85
0.846
2.22
2.29
2.19
1.74
1.58
1.740
1.65
1.87
1.68
0.490 c
1.27
2.26
2.02
1.29
1.63
1.15
1.35
1.32
0.500 c
0.85
0.059
0.033
0.061
382
109
206
3%
109
393
322
392
149
393
101
322
381
392
394
340
379
379
382
322
149
322
206
381
392
394
206
88
88
88
88
88
88
88
88
88
88
88
89
90
91
92
92
92
93
88
88
88
88
88
88
88
88
88
88
88
89
90
91
92
92
92
93
Ru(4,7-bmo-phen):+
90
92
92
92
93
Ru(4,7-dsph-phen):Ru(4,7-dsph-phen$
Ru(rl,Fdsph-phen)$Ru(4,7-dtol-phen):’
Ru(4,7-bphz-phen);’
Ru(4,7-Phi-phen):+
Ru(4,7-bbr-phen):+
88
89
91
Ru(4,7-Phi-phen);
Ru(4,7-Ph,-phen);
88
88
88
88
88
88
88
88
88
88
+
+
Ru(4,7-Phz-phen); +
Ru(4,7-Ph,-phen);+
Ru(4,7-Ph,-phen):+
Ru(4,7-Phz-phen); +
Ru(4,7-Ph,-phen):+
Ru(4,7-Ph,-phen);+
Ru(4,FPh,-phen); +
Ru(4,7-Ph ,-phen): +
Ru(4,7-Cl,-phen):+
87
87
87
Complex
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
MeOH/
EtOH
H2O
H2O
40
MeOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
PMM
l&OH/
EtOH
MeOH,’
EtOH
MeOH/
EtOH
H2O
H2O
f&O
H2O
464 (27400)
465 (36300)
468 (37900)
464 (33000)
463 (28600)
460 (29500)
456 (20600)
MeOH/
EtOH
W
40
Abs (0
solvent
602
595
9.58
0.682
;7lq
Em.
618
7.20
620
5.84
3.73
3.860
6.43
6.10
5.95
6.40
5.83
4.56
4.68
4.680
3.58
3.30
5.34
1.55
615
623
618
635
610
668
(RT)
0.280
0.360
0.387
0.403
0.366
0.028
322
322
101
206
206
206
204,
206
109
206
342
206
322
392
149
275
322
392
327
383
204,
Ref.
Ru(5,6-dm-phen)$+
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen)$+
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen):’
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen)g +
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen):+
98
99
99
99
99
99
99
99
99
99
99
99
96
97
98
99
99
99
99
99
99
99
99
99
99
99
99
99
99
96
91
98
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
97
96
95
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen):+
Ru(5,6-dm-phen):+
Ru(4,7-brmtFphen):+
Ru(4,7+bpph-phen)f+
Ru(4,7-bpmo-phen):’
95
95
100
100
94
100
100
94
Ru(4,%dhy-phen)
(tml-phen):+
Ru(4,7_dhy-phen)
(tml-phen)i+
Ru(4,7-dhy-phen)
(tml-phen)i*
Ru(4,7-bpbr-phen):*
loo
94
MeOH
MeOH/
EtOH
MeOH/
EtOH
NaLS
PMM
H2O
H20
H2O
H2O
H20
n2o
H2O
2:
MeOH/
EtOH
MeOH/
EtOH
&OH/
EtOH
MeOH/
EtOH
H2O
EtOH
“20
450 (19800)
450
453 (204oo)
464 (25500)
465 (33700)
468 (34800)
465 (31000)
450 (16700)
585
590
11.0
0.56
0.39
598
612
583
602
5.95
625
3.08
2.50
1.79
0.513 c
1.404
1.81
1.81
1.810
1.91
2.80
2.77
6.10
6.05
6.00
1.250
2.250
618
620
623
629
629
0.143
0.237
382
109
206
322
392
336
149
12
101
322,
381
392
394
396
109
206
206
206
0.305
0.330
206
363 b
363 b
363 b
0.310
0.03 =
0.05 c
loo
100
100
100
1CUl
100
100
100
100
100
100
100
101
101
101
103
104
105
107
107
108
108
109
109
100
100
100
100
loo
100
100
100
loo
100
100
100
101
101
101
103
104
105
107
107
108
108
109
109
Ligands
109
109
108
108
107
107
105
Ru(taphen):’
Ru(taphe&
Ru(DIAF0); +
Ru(DIAF0); +
Ru(TAP);+
Ru(2,7-dmTAP):+
Ru(BDCMP)f: Ru(DIAF);+
Ru(DIAF);+
Ru(tml-phen)!+
Ru(tm2-p&n):+
Ru(tm2-phen);+
Ru(tm2-phen):+
loo
101
101
101
103
104
Ru(tml-phen)i+
Ru(tml-phen):+
Ru(tml-phen)z+
Ru(tml-phen):+
Ru(tml-phen): +
Ru(tml-phen):+
Ru(tml-phen):+
Ru(tml-phe&
Ru(tml-pher@
Ru(tml-phen); +
Ru(tml-phen)i+
Complex
100
loo
100
100
100
100
loo
100
100
100
100
(a) Mononuclear complexes
TABLE 1 (continued)
MeOH/
EtOH
AN
MeOH/
EtOH
AN
MeOH/
EtOH
H2O
AN
H20
H2O
0.5 M
Hi%
Hz0
H2O
HCI
1.5 M
MeOH/
EtOH
NaLS
HP
H20
W’
H2’3
H2O
H2O
glyCW01
Solvent
436 (15700)
422 (14900)
502 (50100)
440
435 (16000)
424 (16700)
450
440 (19800)
439 (23300)
438 (24500)
Abs (c)
-
Em.
630
600
585
(77 K)
3.1
x7 K)
low
4
(77 K)
Em.
705
-700
683
580
575
574
594
595
608
597
(RT)
0.33
1.4
0.200
0.090 =
2.22
2.08
1.85
0.48
2.03
2.14
3.2 c
1.39
1.52
1.75
2.28
1.81
0.507 =
1.0
;RT)
0.034
0.032
9
(RT)
238
238
40
40
395
216
216
397
398
382
336
149
149
206
322
392
335
149
393
322
381
392
394
340
Ref.
162
162
162
163
163
163
163
181
181
181
181
181
181
181
181
181
181
183
183
184
187
188
162
162
162
162
163
163
163
181
181
181
181
181
181
181
181
181
181
183
183
184
187
188
NO2
NO2
Ru(thpy):+
RU(bt):+
Ru(PTPI);+
188
Ru(Azp~)2
(Btz)”
Ru(NA):+
Ru(NA);+
W~PY),
(Btz)”
Ru(DPAH)$+
Ru(DPA),
(DPAH)
Ru(DPA)
(DPAH);
Ru(DPAH);+
Ru(DPAH): +
Ru(DPA),.H,O-
Ru(DPA);
184
187
183
183
186
186
181
181
181
181
CN
CN
en
aca
163
163
163
163
163
162
162
H2O
MeOH/
EtOH
AN
AN
MeOH/
EtOH
H2O
CH,%
H2O
MeOH/
EtOH
acetone
CH,CI,
Hz0
H2O
H2O
Hz0
H,O
MeOH/
EtOH
AN
MeOH/
EtOH
MeOH/
552 (7200)
463
515 (16600)
505 (14000)
515
498 (13500)
375 ’
MeOH/
EtOH
MeOH/
EtOH
MeOH/EtOH
782
798
755 g
763
7646
730 p
730 m
603 h
650 h
644h
603 h
0.080
- 0.01
- 0.01
2.0
6
1.8
5.9
0.0003
400
668
766
784
835
> 870
2 870
> 870
2 870
0.22
0.026
.-.._“__.--l”_l”l”l~--
360
370
400
399
399
376
375
376
375
376
399
376
376
376
376
209
235
209 b
209
209
209
209
246
246
246
246
246
246
246
246
246
246
246
246
246
246
257
257
247
247
251
251
251
251
251
251
251
246
246
246
246
246
246
246
246
246
246
247
247
251
251
251
251
251
251
251
CN
Ru(DMCH),(CN),
CN
RutDMCH),(CN),
Ru(DMCH),(CN),
Ru(DMCH),(CN),
Ru(DMCH),(CN),
Ru(DMCH),(CN),
Ru(DMCH) &l 2
Cl
CN
CN
CN
CN
CN
Ci
CN
CN
CN
CN
CN
R~(PY~~PY):+
Ru(pynapy)! *
Ru(pq)(biq)i+
Ru(pq)(biq):’
257
257
247
247
Ru(pq)2(biq)2+
Ru(p&(biq)*’
257
257
Ru(p@: +
Ru(hpiq):’
Ru(hpiq)i+
245
245
245
245
245
245
Complex
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
494 (19500)
AN
MeOH/
EtOH
AN
EtCN
EtOH
MeOH
MeOH/
EtOH
MeOH/
EtOH
MeOH
MeOH/
EtOH
M&H
MeOH/
EtOH
AN
MeOH/
EtOH
MF
AN
CHCI,
DMF
MeOH
MeOH/
EtOH
MF
588
636 (12000)
625
618
640 (9800)
575
526 (12500)
533 (7640)
530 (7350)
488
484
483
484
Abs (c)
Solvent
Em.
732
772
865
735
731
722
670
658
733
(77 K)
1.2
1.1
1.2
0.72
0.50
2.0
2.4
3.4
1.1
;77 K)
+
(77 K)
Em.
797
830
824
839
785
687
718
(RT)
0.18
0.14
0.18
0.017
0.007
0.012
221
217
221
221
221
221
40
402
402
274
274
274
274
268
233
351
351
401
401
40
40
Ref.
251
251
256
256
257
257
257
257
257
257
257
257
257
257
257
259
259
259
259
259
259
259
259
259
261
267
281
281
251
251
256
256
257
257
257
257
257
257
257
257
257
257
257
259
259
259
259
259
259
259
259
259
261
267
281
281
CN
259
259
259
261
267
Cl
CN
CN
CN
CN
257
CN
257
257
257
Cl
CN
CN
CN
CN
CN
256
256
251
251
CN
Cl
CN
CN
CN
CN
CN
Cl
CN
CN
CN
CN
CN
Ru(trpyI:+
Ru(trpy):’
Ru(dpp)
:+
Ru(i-biq),(CN),
Ru(i-bk&
Ru(i-biq); i
Ru(i-biq),
Ru(DP); +
Ru(i-biq),CI,
Ru(i-biq),(CN),
Ru(i-biq),(CN),
Ru(i-biq),(CN),
Ru(i-biq),(CN),
Ru(biq)$+
Ru(bWCNh
Ru(bi&+
Ru(biq): *
Ru(biq$+
Ru(bi&0J),
Ru(biWCNh
Ru(bhh KNh
Ru(bhh(CN),
Ru(biWCNh
Ru(biqI,Cl,
Ru(dinapy): +
Ru(dinapy): +
Ru(DMCH); +
Ru(DMCH);+
H2O
AN
H2O
AN
MeOH/
EtOH
AN
MeOH/
EtOH
MF
AN
CHCI,
DMF
MeOH
MeOH/
EtOH
MF
AN
MeOH
MeOH/
EtOH
MeOH/
EtOH
MF
CHCI,
DMF
MeOH
MeOH,’
EtOH
MF
AN
AN
nitrile
AN
455 (22400)
455
474 (14600)
473 (16200)
412
392 (24100)
392 (24100)
436 (15900)
425
437 (17600)
404
593
524 (9000)
524
623 (12200)
625
620
635 (8900)
580
585 (9900)
540 (10550)
540
96.0
40
240
250 j
577
542
2.2
2.6
0.8
0.93
0.91
0.46
0.18
1.8
730 L
718
719
736
780
855
840
732
- 620
615
636
602
555
543
594
632
582
804
705 i
834
825
842
790
-740’
i 0.005
0.73
0.27
0.045
0.25 ’
0.21
0.45
0.05
0.16
0.11
0.17
0.011
0.023
-z 0.001
0.016
0.007
0.009
221
215
131
131
395
403
40
149
217
221
221
221
40
344
221
344
401
401
217
221
221
221
221
40
40,
329
402
402
329
281
281
281
281
281
282
282
282
283
283
283
284
284
284
284
286
286
281
281
281
281
281
282
282
282
283
283
283
284
284
284
284
286
286
Ru(TF’TZ);+
Ru(TPTZ);+
WdW : +
WW:+
RuGh$f +
Wdw):+
Ru(tsite)i+
Ru(tsit&+
Ru(tsite)i+
Ru(tro):+
Ru(tro):’
Ru(tro):+
Wtrpy):+
Wrpy)t+
Wrpy);’
Ww):+
W
WW:+
Ww):+
R@-w):
+
R@w):+
R+PY) : +
281
281
281
281
281
281
281
281
281
281
H2O
H2O
HClO,
MeOH
MeOH
MeOH,’
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH/
EtOH
MeOH,’
EIOH
MeOH/
EtOH
MeOH
MeOH/
EtOH
MeOH/
EtOH
MeOH
MeOH/
EtOH
MeOH/
EtOH
MeOH
MeOH
MeOH/
EtOH
MeOH/
EtOH
Solvent
Complex
Ligands
(a) Mononuclear complexes
TABLE 1 (continued)
501(19200)
501
517 (8880)
610 (2200)
500 (38400)
560 (8200)
475 (15100)
470 (16100)
473
Abs(c)
680
685
632
633
628
629
596
600
599
596
600
(77 K)
Em.
5.6
4.77
7.8
12.3
10
11.0
10.66
10.82
11
;77 K)
0.05
0.57
0.45
0.48
0.479
;7K)
-600
605
628
(RV
Em.
< 0.005
< 0.005
z 0.0012
;RTI
149
101
406
405
406
405
127
406
406
127
406
406
40
127
406
97,
320
104
101
404
405
406
407
Ref.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2sc
2SC
Cl
Cl
2sc
2SC
Cl
Cl
2SC
2sc
2SC
2SC
2sc
2SC
NH,
NH,
2sc
2sc
NH,
NH,
2SC
2SC
2sc
2sc
NH,
NH,
270
a MC emission. b pH dependence.
emission. k At 250 K. ’ At 15 K.
160
160
160
160
159
159
159
159
57
57
57
57
Cl
Cl
1
Cl
Cl
NH,
NH,
Cl
Cl
NH,
NH,
Cl
Cl
Cl
Cl
Ru”‘Cl(bpy),13+
RuCW’pyM2+
[(2SC),CIRu(BPE)
RuCWPY)ZI~+
[(ZSC),ClRu(BPE)
WH,),Ru@PE)
RuCVbpy),l’+
[(NH,),Ru”‘(BPE)
RuCUbpy)z12+
[(2SC)2ClRu(BPA)
RumCl(bpy)J3+
RuCl(b~~)rl~+
[(2SC),CIRu(BPA)
[(NHS)5Ru”‘(BPA)
RuCl(bpy)z13+
I(NH,),Ru(BPA)
RuCXbpy),12+
[(2W,C~Ru(4,4’-bpy)
R~“‘Cl(bpy)~]~+
[(2SC),ClRu(4,4’-bpy)
Ru”‘Cl(bpy)2]3+
RuCl(bpy),]‘+
((ZSC),ClRu(4,4’-bpy)
RuCl(bpy),14+
{(2SC),ClRu(4,4’-bpy)
AN
CH,Cl,/
CH,Cl,/
AN
CHzCW
AN
CH2Cl2/
AN
CH,CI,/
AN
CH,CW
AN
CH,Cl,/
AN
CH,Cl,/
AN
CH,Cl,/
AN
CH,Cl,/
AN
AN
CH,Cl,/
AN
AN
CH,CI,/
AN
Ru(bpy),l’+
i(NH,hRu(44’-bpy)
RuCU’py),13+
((NH,),Ru”‘(4,4’-bpy)
AN
Hz0
KhWzRuW-3)
Wbwh14+
Nw) 2 R&W
412 (8900)
4.68 (16000)
528 (16300)
525 (21000)
606 (7600)
Abs. (t)
704
700
700
700
704
706
1o-3
10-3
10-j
10-3
1o-3
358,
359
358,
359
358
10-j
711
713
358,
359
358,
359
358,
359
358.
359
358,
359
358
10-j
358
358
358
372
103
103
361
708
6xW6
2.7 x lo- 3
:RT)
Ref.
358,
359
358
0.060
0.054
(RT)
I
10-3
706
700
700
780
755
(RT)
(77 K)
769 ~4
Em.
F!m.
’ Air equilibrated solution. d Q~. e Double emission. ’ Shoulder. s Solid sample. h LMCT emission. i Not measurable. j LC
Cl
Cl
NH,
NH,
Cl
Cl
NH,
NH,
Cl
Cl
Cl
Cl
NH,
1
57
57
1
267
NH,
1
1
NH,
1
1
NH,
1
1
EtOH
1
1
Ru(biv9,14+
Kbm)2 Wdw)
Wwh14+
1
267
1
1
1
1
1
H2O
61
Ww)2 Wwm)
1
1
1
1
Solvent
Complex
Ligands
(b) Polynuclear complexes
+
Y
1
1
MPP
Ns
N3
MPP
N3
SCN
SCN
H2O
H2O
N3
H2O
H2O
H2O
H2O
H20
H*O
PPP
H
1
1
1
1
1
1
1
1
Ru(bpy) 2(SCN)2
Ru(bpy),(MPP);+
Ru(bpy),(W2+
Ru(bpy),(N3)2+
Ru(bpy) 2(PPP)H +
truns-Ru(bpy)z(H20);+
cis-Ru(bpy)2(H20)i’
cis-Ru(bpy),(H,O);+
rrans-Ru(bpy),(H,O);+
Ru(bpy) 2(CO)Cf
+
cis-Ru(bpy)2(CO)Cl +
R@PY) 2(CO)Cf
+
Ru(bpy),(H,V+
Ru(bpy) 2(NO)@ +
Ru(bpy),(CO):+
Ru(bPY),(CO);+
Ru(bpy) 2(CO)H +
DMF
AN
H,SO, 1 M
H,SO, 1 M
H,SO, 1 N
H,SO,, 1 N
CH$l,,ClAN
AN
PY
PY
H20
AN
CH,Cl,,ClMeOH
MeOH
HZ0
MeOH
MeOH
1
1
1
1
1
1
1
1
+
Ru(bpy),(CO)Cf+
cis-Ru(bpy)2(CO)Cl+
Ru(bpy),(CO)Cf
Ru(bpy),(CO)CL+
cis-Ru(bpy)2(CO)CI+
Wbw) 2 (AWl+
Wbw) 2 (ANXCO)2 +
CH,Cl,,ClCH,Cl,,ClH,SO, 1M
CH,Cl,,ClI
AN
AN
AN
CH,Cl,,Cl-
WbMW;+
RuhvMAN)~+
WbpyWWZ,+
AN
AN
AN
Cl
co
co
co
co
co
co
co
co
co
H2
NO
co
co
H
1
I
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
AN
AN
AN
AN
AN
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
co
co
co
Solvent
Complex
Ligands
Photoehemical properties
TA3LE 2
0.026
0.045
0.04
0.025
-0
< 0.001
0.05
0.09
0.045
0.31
0.32
0.44
0.12
+
Wbpy)2 (AWN,)*
Decomposition or
photosolvation
Photosolvation
+
-+ Ru(bpy),(AN)f+
Photoaquation
Photoaquation
Photoisomerization
Photoisomerization
Photoanation
+ Ru(bpy) $12
CO photosubstitution
Co photosubstitution
CO photosubstitution
CO photosubstitution
CO photosubstitution
H, photosubstitution
+ Ru(bpy)2(AN)C12’
+ Ru(bpy), (CO)Cl+
CO photosubstitution
Disappearance
-, Ru(bpy),Cl,
CO photosubstitution
CO photosubstitution
CO photosubstitution
+ Ru(bpy),(AN)Cl+
-, Ru(bpy) 2(AN)Cl+
Photoaquation
Type of reaction
426
318
409
318
318
410
411
410
318
412
411
410
411
410
412
413
318
410
410,
414
414
318
318
415
415
318
416
416
Ref.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
11
51
59
61
107
107
111
111
111
111
111
111
111
1
1
1
1
1
1
1
1
1
1
Cl
Cl
NCS
111
111
111
111
57
Ru(bPY),(PYw+
Ru(bpy) 2(py)Cl+
RQPY), (PYXNCS)’
Ru(bpy),(py);+
Ru(bpy),(py);+
Ru(bpy),(py):+
R~(~PY),(PY);+
Ru(bPY):+
Ru@PY):+
R@PY); +
Ru(bPY):+
Ru@PY):+
R~@PY);+
Ru(bpy); +
Ru(bPY)2(6-stY-bPYJ2+
Ru(bp
y)2(4,4’-bp y); +
Ru(bpy),(bpzJ2+
Ru(bpy),(bpyW2+
Ru(bpy)2(DIAF)2+
Ru(bpy),(DIAF)‘+
A-Ru(bpy);+
Ru(bPY):+
Ru(bPY);+
Ru(bpy): +
Ru(bpy),WS),
Ru(bpyW 2
Ru(bPY):+
Ru(bpy): +
Ru(bPY):+
Wbpy):
+
R4-w):+
H*O
H,SO, 1 N
HC112 M
HCllM
HCllM
HCl2M
NaHCO,
NaOH 0.3 M
AN
CH,Cl,,ClAN
AN
AN
CH,Cl,
CH&ClMeOH
CH,Cl,,ClAN
CH,Cl,
CH,Cl,,XCH,Cl,,Cl-
AN,ClAN,ClAN
AN
CH,Cl,,ClCH,Cl,,ClCH,Cl,,ClCH,Cl,,ClDCllM
DMF,Br-
0.036
0.211
0.18
0.20
0.00033
0.0008
0.20
< 0.0001
< 0.0001
0.004
0.043 a
0.04
0.00029
< 0.0001
> 0.0015
0.00019
0.01
0.003
< 0.0003
0.029
0.04
0.068
0.100
0.030
0.00036
0.0003
387
366
417
225
366
124
124
409
121
418
144
366
121
--) Ru(bpy) 2(-bpyIC1
+
121
-, Ru(bpy) 2(-bpy)Cl
+
343
d Ru(bpy) 2(-b~y)Cl+
Disappearance
419
j Ru(bpy) 2(-bpy WH) + 343
Disappearance
420
Photosolvation
345
+ Ru(bpy) 2(4,4’-bp y)Cl + 318
L&and loss
225
225
Ligand loss
Photosubstitution
421
Photosubstitution
421
318
* Ru(bpy) $12
Cl’ photosubstitution
422
--) Ru(bpy)2(NCS)Cl
423
Photosubstitution
421
Photosubstitution
421
423
--) Ru@PY),(PY)X+
318
j Ru(bpy)z(~~)Cl+
+ Ru(bpy) 2Rr2
Racemization
Photoanation
h Ru(bpy) 2(-bpy)Cl+
+ Ru(bpy)2(DMF)Brf
-, Ru(bpy),(AN)2,+
Ligand loss
Photoanation
Photoanation
Photoanation
Photoanation
Photoanation
Photoanation
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ligands
137
145
146
147
157
157
125
126
125
111
111
111
111
115
118
118
118
118
118
119
119
124
124
124
124
124
125
TABLE 2 (continued)
Ru(bpy),(Pyd);+
R@PY)*(PZH)f’
Ru(bpy),Wd);+
Ru(bpy),(NMI)Z,+
R~(~PY)z(DPM)~+
R~(~PY)z(DPM)~+
Ru(bpy),(c-stylb);+
126
137
145
146
147
Ru(bpy),(c-stylb)CI+
Ru(bpy)z(t-stylb);’
125
Cl
Ru(bPY),(PY);+
Ru(~PY),(PY);+
R~(~PY)~@Y):+
R~(~PY),(PY);+
R~vJPY),(~+PY);+
Ru(bpy)s(PicXCO)2’
Ru@py), WXCO)"
Ru(b~~),(pic):+
Ru(bPY),(Pic)2,+
Ru(b~~Wc)z,+
Ru(bp
y)z(4acet yI-p y)CI +
Ru(bp
y)2FacetYI-p
y)22’
Ru(bpy),(PVI’XCI)+
RU(~PY)~(PVPXCO)~+
RU(~PY),(PVPXCO)‘+
Ru(bpy)s(PW:;,
Rutb~~)z(PvP);+
Ru(bpy),(t-stylb)Cl+
111
111
111
111
115
co
co
118
118
118
Cl
119
Cl
co
co
124
124
Cl
Complex
+ Ru(bpy)z(3-I-py)CI+
CO photosubstitution
CO photosubstitution
Photoanation
Photoanation
Photoanation
+ RU(~PY),CI,
+ Ru(bpyX4-acetyl-py)Cl+
Cl- photosubstitution
CO photosubstitution
CO photosubstitution
L&and loss
Photosubstitution
Ligand isomerization
0.20
0.15
0.12
0.16
0.06
--) Ru(bpy) 2(pyd)Cl
+
0.20
Photoaquation
< 0.001 + Ru(bpy) ,(imid)Cl+
< 0.001 + Rt@py),(NMI)Cl+
Photoanation
0.24
0.21
Photoanation
BN
BN
BN
CH,Cl,,ClH,SO, 1 M
CH,Cl,,ClCH,Cl,,ClAN,ClCH,Cl,,Cl-
Ligand isomerization
Ligand isomer&ion
Ligand isomerization
0.09
0.087
0.21
0.17
0.24
0.07
0.29
+ R@PY) 2 (py)Cl+
Photosubstitution
Photoaquation
Photosubstitution
Type of reaction
0.22
0.170
0.26
+
PY
AN
MeOH
BN
PY
AN,ClCH,Cl,,ClH,SO, 1 N
CH,Cl,,ClCH,Cl,,ClMeOH
MeOH
H,SO, 1 M
MeOH
CH,Cl,,ClMeOH
H2O
CH,Cl,,Cl-
Solvent
409
421
318
422
318
410
410
366
366
366
318
318
422
410
410
126
422
424,
425
424,
425
424,
425
424,
425
318
318
318
318
366
366
Ref.
AN
Hz0
68
68
111
103
180
68
68
68
68
103
180
285
68
68
68
68
103
180
285
a Under 100 atm 0,.
111
H2O
H2O
NH3
NH3
AN
AN
NH,
68
68
AN
Cl
Cl
37
AN
AN
AN
59
59
59
59
59
37
54
59
59
59
59
59
59
59
37
54
59
59
59
59
59
59
59
61
68
68
37
37
15
157
158
158
158
59
61
15
37
1
1
1
1
59
61
15
15
1
1
1
1
1
1
15
15
RU(PY&PY)
:+
Ru(dpt);+
trans-Ru(phen),(AN)i+
rruwRu(phen),
(H20)(AN)2+
cis-Ru(phen),(H,O)i+
Ru(phen):’
Ru(phen): ’
frans-Ru(phen), (py);’
Ru(TAP);+
V’WNHd&@wm~4+
Ru(bpy),(DPW2+
Ru(bpy),(DPQ2+
Ru(bpy),(DPE)2+
RWPYMDPE)~’
Ru(bPYxbPz);+
Ru(bpyXbpym)‘z+
Ru(4,4’-dm-bpy)i+
Ru(4,4’-dm-bpy),
(4,4’-DCE-bpy)2+
Ru(4,4’-dm-bpy)
(4,4’-DCE-bpy);’
Ru(4,4’-DCE-bpy); +
Ru(6,6’-dm-bpy),(AN)i+
Ru(bpz),(AN)Cl+
Ru(bpz),(AN)Cl+
Ru(bPz):+
Ru(bPz):+
Ru(bpz);+
Ru(bpz):+
Ru(bpz)$+
H2O
AN
CH,Cl,,X-
H2O
CH,Cl,,ClCH,Cl,,ClAN
HZ0
H2O
AN
CH2C12,ClCH,Cl,,ClAN
AN
AN
AN,ClAN
AN,ClAN,Cl-
CH,Cl,,Cl-
H2SO41 N
AN,CICH,Cl,,ClH2SO41 N
AN
AN
CH,Cl,,ClCH,Cl,,Cl-
Photoanation
Photoanation
Photoanation
Photoanation
Ligand loss
Ligand loss
Photoanation
Photoanation
Photoanation
Photoanation
Photoisomerization
Photoanation
0.020
Photoanation
0.014
Photoisomerization
< 0.001 Deehelation
Photosolvation
0.0040 Photoanation
(X- = Br-, SCN-)
0.001
--) Ru(bpz) $12
c 0.001 --) Ru(bpz),Cl,
+ Ru(bpz) 2(AN)Cl+
0.37
Photoanation
0.37
Ligand loss
0.45
Photoanation
0.37
Photoanation
< 0.0005 Decomposition
Photoisomerization
Photoisomerization
0.012
c 0.001 Photoanation
0.04
0.18
0.58
< 0.3
0.035
< 0.001
0.005
< 0.001
429
124
124
429
398
369
150
135
427
382
388
382
387
225
387
388
428
429
429
135
366
366
366
366
225
225
135
135
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Hz0
AN and
DMF
AN
DMF
AN
AN
DMF
AN
fWw):+
Ww):+
1
1
1
1
Hz0
DMF
AN
AN
AN
AN
AN
DMF
Why):+
R~(~PY):+
Ru(bpy): +
R@PY): +
R@PY):+
R~(~PY):+
R~(~PY):+
R*PY):+
AN
AN
AN
acetone
R~(~PY):+
Ww):+
R@PY):+
R4by):+
R~(~PY):+
Ru(bpy):+
Ru(bpy):+
Ru(bpy)f+
Ru(‘m9:
+
WW: +
WTY):+
:
Hz0
DMF
DMF
R@PY): +
R~@PY):+
Ru(bpy):+
Ww): +
AN
Why): +
1
1
1
1
1
1
1
1
1
1
Solvent
Complex
Ligands
(a) Mononuclear complexes
SSCE
Ag/AgNQ
SCE
SCE
SSCE
SSCE
AsRE
Ag/AgCI
SSCE
s ref
SCE
SCE
Fc+/O
NHE
Fc+/O
SSCE
SSCE
AgRE
s ref
SCE
AgRE
SCE
ABRE
SSCE
SCE
SSCE
SCE
SCE
SCE
SCE
SCE
NHE
SCE
Fc+/O
SCE
Fc+/O
SSCE
SCE
SSCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
S’WH,O)
Ref.
1234
1260
1290
1263
1290
1290
1354
1665
1490
1290
1290
1ooo
1270
1260
1290
1270
1240
1260
1240
- 1338
-1760
- 1280
-1760
-1355
-1810
-1332
- 1060
-1100
-1400
- 1250
- 1330
-1760
-1310
- 1310
- 1270
- 1270
-1760
- 1350
2030
-840
-800
-790
-840
840
800
760
840
*Gd
at -54’C
E/p f. diff.
pulsep.
Diss. D.J.
Salmon, 1977
= -300mV
v SCE
AatE
at -54’C
- 54’C,
Ed1 = - 2540
E,, = AN,
E, = DMF
-
Notes
457
385
437
451
243
62
229
369
69
378
431
433
443
444
169
149
270
63
Ref.
Ground and excited state redox properties, This Table lists the first oxidation and the first reduction potential in the ground state (E,, and &,,> and in the lowest
excited state (*E,, and *E rsd, calculated according ta eqn. (8) and (9)), the reference and the standard electrodes, and the energy of the lowest lying excited state, in
cases where the O-O excitation energy is known. Ail potentials are given in mV; the precision should be taken from the original literature
TABLE 3
R@PY): +
Ru@PY): +
R~(~PY):+
Wbpy): +
R@PY): +
R~(~PY):+
-3~~1: +
Wpy): +
WJPY):+
R~(~PY):+
R~@PY): +
R~(~PY):+
R~(~PY):+
Wbpy): +
R@PY): +
Ru(~PY):+
Wbpy); +
WJPY): +
R~@PY):+
AN
R~@PY): +
AN
R~@PY): +
Ru@py)i +
H2O
AN
Wbpy): +
AN
W’py): +
AN
Wbpy) z
(4-n-bpy)‘+
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
7
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1280
970
1365
s ref
NHE
As/AP+
Ag/AfjNO,
1190
1280
SCE
NHE
1260
1260
1260
1290
1290
1260
1010
1290
1354
1402
1220
1290
1270
1290
1240
1260
850
1270
1268
1260
1290
1260
1354
1270
SCE
Ag/AgNO,
Ag/AgN03 * NHE
NHE
NHE
AN
l
SCE
NHE
SSCE
SCE
SCE
SCE
SSCE
SCE
SCE
SCE
SCE
SCE
SSCE
SSCE
NHE
Fc+/O
SCE
SCE
SCE
NHE
SCE
NHE
SCE
AUAgNO,
Ag/AgNO,
AUAgC1
SSCE
SCE
SCE
SCE
SSCE
SCE
SCE
SCE
SCE
SCE
SCE
SSCE
SSCE
SCE
AdAgNO,
SCE
SCE
SCE
SCE
AN
AN
H2S04
AN
AN
AN
AN
AN
DMF
AN
AN
AN
0.5 M
AN
H2’3
AN
AN
AN
AN
AN
H20
AN
AN
AN
AN
AN
Ru(bPY):+
W’JPY): +
Wpy): +
R~(~PY):+
W’JPY): +
W’JPY):+
Ru@p
y):+
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
- 1320
- 1650
-560
-1345
-1350
-1350
-1230
-1350
-1360
- 1320
- 1320
- 1250
-1332
-1340
-1280
-1760
-1330
-1340
-1340
-1350
-1350
-1350
-1330
-1260
-1332
2130
2130
2120
2100
- 830
-840
- 870
- 870
-900
-810
- 830
-810
-840
780
780
760
770
760
770
840
760
= E/P&
* fWbpy):+/
+ 1260 mV
* Mbpy): +/
+ 1260 mV
_
E,
-40°c,
_
Peak potentials
360
224
393
135
307
239
512
329
40
397
103
210
380
354
60
497
501
403
509
387
487
489
402
176
235
232
474
477
131
482
482
4
I
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
30
30
30
26
26
26
18
17
16
16
16
15
13
13
12
11
Ru@pY)2
(4-n-bpy)*+
7
1
1
R@PY),
(4,4’-DTB-bpy)2+
R@PY),
(4,4’-DTB-bpy)‘+
Ru(bpy),
(4,4’-DTSbpy)2 +
Ru(bpy),
(4,4’dph-bpy)2+
R@PY),
(4,4’-dph-bpy)2+
R@PY)~
(4,4’-dph-bpy)2+
R@PY) z
(4,4’dn-bpy)‘+
R@PY)~
(4,4’-dBr-bpy)*’
R@PY),
(4,4’-dCl-bpy) ’ +
Ru@PY),
(4,4’-dCI-bpy)2+
R@PY),
(4,4’-dCl-bpy) ’ +
R@PY),
(4,4’-dm-bpy)2+
R~(~PY),
(3,3’-dm-bpy)2+
R@PY),
(3,3’-dm-bpy)”
R@PY),
(6-tol-bpy) *+
R@PY),
@-sty-bpy)*+
Ru(bpY),
(4-n-bpy)**
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 3 (continued)
AN
AN
AN
AN
DMF
AN
AN
AN
AN
AN
AN
AN
AN
AN
acetone
acetone
AN
AN
Solvent
l
*
Ag/AgNO, *
Ag/AgNO,
AUAgNO,
SSCE
WAgNO,
&/&NO, *
AdAis+
Ag/AgNO, *
AiUAgN’J,
Ag/Ag+
Ag/AgNO,
&/kW,
WA@
WAN
WAN’,
Ref.
NHE
NHE
NHE
SSCE
Fc+/O
NHE
NHE
s ref
NHE
NHE
s ref
NHE
NHE
s ref
s ref
NHE
1210
1210
1210
1233
1240
1480
1020
1300
1300
1300
930
1220
1220
1490
1530
1370
1370
- 1370
- 1370
-1365
- 1308
- 1720
- 510
-1140
-1140
-1140
- 1680
-1370
- 1370
-1110
-1120
-560
- 560
2100
2100
1770
2040
2040
2080
2080
1890
1890
-890
-890
- 870
-290
-740
-740
- 860
-860
-520
- 520
730
730
1260
900
900
710
710
1330
1330
*&I
l
Ru(bpy):+/
+ 1260 mV
at -54’C
* Ru(bpy):+/
+ 1260 mV
Erd = ii-r.
* Ru(bpy):+/
+ 1260 mV
* Ru(bpy):+/
+ 1260 mV
+ 1260 mV
* Ww):+/
Notes
40
329
239
473
473
224
40
307
344
40
239
307
40
329
345
345
344
40
Ref.
z
43
44
54
61
61
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
1
1
1
1
1
1
1
61
61
61
61
60
59
59
59
59
58
57
57
51
57
56
38
1
1
58
Cl
Cl
57
57
Wbpyh
(bPzJ2+
W’PY)~
@PzY+
W’PY),
@PZ12’
R@PY),
Wd2+
W~PY),
@JPW’
Wbpyh
(bpym)2+
R@PY),
(bpym12+
W~PY)Z
(bPYm12’
W~PY) 2
(bpymj2 +
W~PY) 2
(bpymj2’
W~PY) 2
(bpym)l+
M’PY),
(m-4,4’-bpy)i+
Mbpyh
(4,4’-bpy)(Cl)+
Wbpyh
(4,4’-bpy)(Cl)+
‘WPY)~
(4,4’-bpy):+
R~(~PY),
(H4-bpy12 +
Mbpy),
(4,4’-bpy):+
Mbpyh
(6,6’-dm-bpy)’ +
WJPY) 2
(4,4’-DCA-bpy)‘+
Wbpyh
(4,4’-DHC-bpy)‘+
(4.4’-DCI-bpy)2f
Ru(b9,
AN
AN
AN
AN
AN
AN
AN
AN
AN
DMF
AN
AN
AN
AN
AN
AN
AN
AN
DMF
iBN/AN
CH,Cl,
NHE
SCE
SCE
NHE
*
NHE
NHE
sref
SCE
SSCE
SSCE
SCE
NHE
SSCE
Fct/O
SSCE
SCE
SSCE
SCE
SSCE
SSCE
* / NHE
Ag/‘AgNO, *
Wbpy):+
Ag/AgNO,
SCE
SSCE
SSCE
SCE
Ag/AgNO,
SSCE
SSCE
SCE
SSCE
SCE
SSCE
SSCE
Ag/AgNO,
Ag/AgNO,
SCE
SCE
Ag/AgCl
1385
1370
1290
1360
1400
2270
1500
1485
1490
1340
790
790
1320
1320
1238
1285
1380
1350
- 1025
- 1510
- 1010
- 1020
-280
-890
-910
-1340
-910
-760
- 1317
- 1330
- 930
-990
-550
1940
550
-440
1440
1050
* Wbpy):+/
+ 1260 mV
reference
= 1260 mV
E values are
calculated
* Ru@PY):+/
t 1260 mV
at -54’C
_
t 1260 mV
* W’w):+/
512
361
465
360
454
229
387
40
473
473
229
357
510
358
459
318
511
514
270
354
447
68
68
71
85
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
N,
Cl
Cl
AN
AN
AN
AN
AN
AN
88
AN
67
1
1
70
Wm9,
62
1
1
R@PY) 2
(ANXN,) +
R@PY),
(AN)@) +
ROpy),
(AN):+
R~@PY),
(AN);+
cis-Ru@Py)2
(AN):+
R~@PY),
(AN)i+
R@PY),
(AN):+
R@PY),
(AN):+
R@PY),
(AN):+
R@py),
(AN)(a) +
ROpy),
(4,%PlGphen)‘+
RM’JPY),
(2,9-dm-phen)2+
R~(~PY),
(Pc-phen)2 ’
RM’JPYI,
(2-mea-phen)*+
R~(~PY),
(Phe#’
R~@PY),
@hen)*+
R~PY)Z
(h-phen)2+
(4,4’-dm-bpym)”
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
Ag/AgNO,
SSCE
AN
AN
SSCE
SSCE
SSCE
SSCE
AN
AN
AN
AN
SSCE
SSCE
AN
AN
SSCE
SSCE
AN
AN
SCE
SCE
AN
AN
Ag/AgCl
AdAgC’
SSCE
SSCE
Ag/AgNO,
SCE
Ref.
acetone
acetone
AN
AN
AN
AN
Solvent
*
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
NHE
SCE
s ref
s ref
SSCE
SSCE
NHE
SCE
Stand.
650
840
860
1470
1440
1300
1410
1440
1440
1440
1245
1180
1520
1440
1230
1290
1240
1250
II,,
- 1320
- 1030
- 1130
- 1360
- 1360
Ed
2120
Eomo
-910
- 880
*&
780
760
*Ed
Diss. D.J.
Salmon, 1977
Eox-tram
1440 mV
E/p f. diff.
pulse-p.
E/p f. diff.
pulse-p.
+1260 mV
476
385
318
489
476
462
455
450
369
318
239
360
451
451
210
458
40
360
_
* Why):+/
Ref.
Notes
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
Br
Br
BA
BA
AN
AN
AN
AN
AN
AN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
CN
SEE
Br
PRC
BA
NO3
NO1
H,O
NO
NO
NO
W’J),
Wbm),
OJ),
Ww),
002
Wbv),
WW2
fWw92
KW2
W’wJ,
092
Rdw92
GN),
W’w),
OJ),
WW2
W’J),
Ww92
((392
RuOw92
0’92
Ru(bpy),
(Br)(SEE)+
cis-Ru(bpy) 2
Ru(bpy) 2
(Br) 2
(BA)(PRC)*+
W’JXN%)+
Ww),
W’JXNW+
Ww)z
(Wt+
Wwh
Ru(bpy) 2
Rdbpyh
(AN)(NO)‘+
cis-Ru(bpy)2
(AN)(H,O)*+
Ru(bpy)z
(AN)(NO)3+
(AN)(NO)3+
Ru(bmh
DMF
AN
DMF
DMF
H2S04
0.5 M
DMF
AN
DMF
DMF
AN
DMF
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
Ag/A@h
Ag/AgNO,
Ag/AgNO,
A&‘AisN4
SCE
SCE
SCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SCE
SCE
SCE
Fct/O
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
830
810
840
840
930
850
805
896
360
800
730
920
370
1240
1030
1020
1170
560
560
560
- 1590
-1640
- 1560
- 1560
-1540
- 1605
-1572
- 2020
-1633
- 1680
- 1470
- 350
- 350
2140
2150
2050
-1300
-1160
- 1320
580
440
370
* Ru(bpy):+/
t 1260 mV
* R@py):+/
t 1260 mV
* Ru(bpy);+/
t 1260 mV
* Rdbpy): +/
t 1260 mV
E = E/p,a
and E/p,c
-
_
E,, = E/p,a
E,,-trans
1150 mV
221
221
40
221
509
176
477
471
470
469
325
486
489
492
492
464
464
450
488
464
441
co
Cl
Cl
Cl
Cl
Cl
For
Cl
co
co
co
co
co
co
co
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Ru(bpyI2
(Cl),
Ru(bpy),
AN
co
1
1
Cl
Ru(bpy),
(CO)(For)+
H
co
1
1
Ru(by),
(Cl) 2
R~(~PY),
(Cl),
R@PY),
(Cl) 2
R@PY)Z
(Cl),
Ru(bpYI2
(Cl),
R~(~PY) 2
(Q,
Go2
Ru(bpY),
(CO)(Cl) +
R@PY),
(CO)(Cl) +
Ru(bPY) 2
(CO)(Cl) +
R@PY),
(CO)(Cl) +
cis-Ru(bpy),
(CO)(Cl) +
R@PY),
(Ctw
cis-Ru@py)2
(W(H)+
Ru(by)2
(CWHI)’
Ru(bpyI2
(CO)(AN)2+
H
co
1
1
Ru(bpy),(CN)
((CN)Pt(dieu))2’
CN l
CN
1
Complex
1
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
AN
SCE
SCE
AN
DMF
SCE
SSCE
AN
AN
SSCE
SCE
AN
AN
SCE
SSCE
SSCE
SCE
SSCE
SCE
SSCE
SSCE
SCE
SSCE
SCE
SCE
Ref.
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
DMF
Solvent
SCE
Fc+/O
SCE
SCE
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SCE
SSCE
SCE
SSCE
SSCE
SCE
SSCE
SCE
SCE
Stand.
2140
1140
1140
1030
320
3
308
310
300
310
350
320
1470
1460
1500
1500
1500
1550
>1900
E,,
- 1610
- 1950
-1320
-1300
- 1320
-1320
-1150
- 1450
- 1620
Ed
2190
Eo-0
ox
-1700
-1160
*E
570
*&cd
385
431
222
483
210
479
483
449
318
318
479
483
449
325
Ref.
479
470
469
Diss. D.J.
457
Salmon, 1977
467
E,, = Vp,a
CN * is(CN)
Pt(dien)
Notes
K
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
en
en
TN
SP
SF
N3
N3
N3
N3
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
SP
SF
NO
NO
N3
N3
NO3
NO2
NCS
NO
NO
NO
NO
NO
Cl
Cl
Cl
Cl
2
2
2
2
Wbpy),
(en)2+
(en)2+
Ww),
vv2+
RuMy),
P),
W’wh
WI2
Wbw),
V3XW2
W’w),
(N3MW2+
Wwy),
cN3)2
Ru(W)
(N3)2
R~JPY),
OW3
Ww)
OXNO
Wbpy),
(WNCS)
Wbpy),
)
1
RU@PY)2
(Cl)(NO)2’
Wbpyh
(Cl)(NO)‘+
Wbpy),
(Cl)(NO)‘+
Wbpy) 2
(Cl)(NO)‘+
+
(Cl)(NO)2+
Ww92
co2
Why)
02
Wx-v~,
(a
W’m9,
02
W’w) 2
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
H2O
Acetone
AN
AN
AN
DMF
CH,Cl,
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
l
s ref
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
Ag/Ag
NHE
NO, *
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
NO3
Ad&
NO3
Ag/Ag
SSCE
SSCE
933
950
- 980
- 280
120
180
170
190
170
450
570
500
40
290
200
190
190
310
50
310
320
- 1485
- 630
- 630
-1590
-600
-600
- 1670
-2110
-1670
1650
- 970
-1340
-20
= E/P,c
E,
= E/p,c
* Ww):+/
+ 1260 mV
E,
* Wbpy):+/
+ 1260 mV
E, = E/p,c
486
486
488
441
40
476
464
464
489
488
488
488
464
441
40
505
489
367
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
111
Cl
Cl
CN
111
111
CN
AN
111
111
AN
111
AN
@yXCN)+
Bu(bpyJ,
(PYXQ +
R~(~PY),
(PYXCU+
Ru@py),
@yXAN)‘+
RufbpY)z
@yXAN)‘+
Ru(bpy),
(PYXAN)~’
R@PY),
(PYXAN)”
R~@PY),
@yXCN) +
Ru@pY),
111
111
Ru(bpY),
(phen-dione)2’
R@PY),
(taphen)2+
Ru(bpy),
(taphen) +
(DIAFO)‘+
Wbpy)2
(ox)
Ru(bpy),
(ox)
R@PY)~
w2+
Wvy),
w2+
Ru@PY)~
(en)2+
WW
110
109
109
108
ox
ox
en
en
AN
1
1
en
1
1
w2+
Wvyh
1
1
en
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
SSCE
SSCE
SSCE
AN
AN
AN
AN
AN
SSCE
SSCE
SCE
SSCE
AN
AN
SSCE
SSCE
AN
AN
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
NHE
&/AiW,
AN
*
NHE
NHE
Fc+/O
SCE
s ref
SSCE
SCE
Fc+/O
Stand.
Ag/A@‘JO,
WAgNO, *
SCE
Ag/Ag+
SSCE
SCE
Ref.
AN
AN
DMF
AN
Hz0
AN
AN
DMF
Solvent
790
800
1040
1040
1350
1360
1360
1280
1350
1370
1370
1360
20
450
620
960
980
450
E,,,
- 1480
-65
- 720
- 720
- 670
- 1980
- 1598
- 1498
-1910
Erod
1870
2160
Eo-0
ox
-500
-800
*E
1150
1490
*Ed
* Wbpy): +/
+126OmV
* Ru(bpY):+/
+1260mV
E,, = E/m
Notes
318
364
479
364
489
476
455
364
480
40
238
40
470
469
317
495
477
470
Ref.
111
111
111
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
111
111
111
111
111
111
111
111
111
111
111
111
111
111
111
111
111
111
1
1
111
111
111
111
111
111
111
111
OH
NO
NO
NO
NO
NO
N3
N,
Cl
Cl
Cl
Cl
Cl
@Ywd+
W~PY),
@YxNO)’ +
R~(~PY),
(PYxNOj3+
RJJ(~PY),
(PYxNO13+
R@PY),
(PYWNO)~
+
WbPy) 2
fPYxNO)3+
R@PY) z
(PYWOH)+
Ru(bpy),
@Y):+
R~(~PY)2
(PY):+
Ru(bpy) z
(PY):’
cis-Ru(b~~)z
<PY):+
Ru(~PY)z
@Y):+
R@PY) z
(PYI22’
UbPy) 2
<PY>:+
R@PY) z
@YG’
Mbpy),
(PYXN,)’
(PYW) +
WbPy),
@YMCb’
R@PY),
(PYxCb+
Wbpy),
(PYKU +
Wbpy),
(PYxCb+
Wbpyh
Wvyh
AN
DMF
AN
AN
AN
AN
SCE
SCE
SSCE
SSCE
SCE
SSCE
SSCE
AN
AN
SSCE
SSCE
AN
H2O
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
SCE
Fc+/O
SCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
1265
760
1270
1280
1300
1300
1300
1240
230
530
530
530
530
530
580
580
790
760
770
790
117
- 1365
- 1790
- 1383
- 1320
- 370
- 370
-1500
- 1510
1280 mV
Diss. D.J.
Salmon, 1977
E,,-tram
&I = E,'P,c
T= 2O.O”C
318
364
364
488
464
455
441
364
476
364
510
489
367
479
466
111
111
111
111
1
1
I
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
111
111
111
111
111
111
111
111
111
111
111
111
111
1
1
ON3
ON2
ON1
NO3
NO3
NO3
NO,
NO2
NO2
NO2
NO2
NCS
f-W
f-W
*,O
Cl0
111
111
111
1
1
R@PY) 2
(PYXNO,)+
Ru(bpy),
(PYXNO,)+
Mbpyh
(PYKN~)+
Wbpy) 2
(PYXNW+
Ubpy),
(PYXNW+
R@PY) 2
(PYXNW+
Wbpy) 2
(PYMNW+
Wbpy) 2
(PYXON~I~+
Wbpy) 2
(PYKON~)~+
Wbpy) 2
(PYKON~)~+
R~(~PY),
(PYX*~O)~+
Wbpy) 2
(PYKNW+
Wbpy) 2
(PYKNO~)+
(PYX*,O)~+
Wbpy),
@YX*~Q~+
(PY):’
Ru(bPY),
(PY)Z’
Ru(bPY),
(PYG’
Wbpyl2
(PYx~ol) +
Wbpy) 2
Why) z
111
1
1
I11
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
AN
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
AN
AN
SSCE
SSCE
AN
AN
SSCE
SCE
AN
AN
SSCE
SSCE
AN
AN
SSCE
SCE
SCE
SSCE
SSCE
SSCE
1M
HCIO,
AN
H2S04
1M
AN
AN
AN
SSCE
SSCE
AN
AN
Ref.
Solvent
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
Stand.
1730
1750
1760
910
910
960
910
1060
1060
1060
1060
850
790
780
710
1090
1250
1290
1300
E,,,
-1460
- 1350
- 1320
&,
E”-’
-860
lE,,
760
*E,
E,, = E/p,a
E,, = E/m
_
461
461
461
489
464
455
364
489
479
_
E,, = E/w
464
364
489
463
463
364
489
210
489
367
Ref.
E,, = E/w
-
Notes
8
111
111
112
112
112
113
115
122
122
122
123
123
123
123
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
123
119
119
117
116
111
1
1
123
NO
Cl
Cl
AN
N4
Hz0
122
119
Cl
117
11s
WA
PT!s
ON4
2
AN
AN
wPY):+
WPYK’J)+
Wvyh
V-VPYKW~+
Wbyh
AN
AN
(t-bupyXN4) +
AN
M~PY),
V-WYKAN)~+
AN
Mbpy),
(4+lvKC~)’
AN
Ru(bpyI2
w=tYl-PY);+
AN
Wbpy),
(t-bupy):+
CH2C12
WJPY),
(t-bupy)(H20)2+
AN
W’~PY) 2
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
H2S’h
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
1M
PC
AN
AN
AN
AN
RuO,
(3Pyr-PY):+
AN
R@PY),
(4-acetyl-py)(c1)+
AN
W~PY),
R@PY),
(3-AEP)2+
Wbpy),
(3-I-PYI$+
R~(~PY),
(2-AEP)2 +
R~(~PY),
(Ph4A)2’
Ru(bpy),
(PMA)2+
W~PY),
(PM.A)2+
Ru(bpy),
@YNlw+
R@PY),
@YMTFA) +
(PYKON~)~’
WW
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
?
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
1250
470
760
740
1290
880
1180
1230
1450
820
990
1020
1360
1120
1120
970
1330
890
900
1770
-1360
-1490
-1500
-1440
- 930
polymer film
polymer film
ref + stand
not ind.
E,, = E/p ,a
_.^__“_.___..
448
455
455
448
455
489
489
489
318
318
446
210
318
495
495
494
494
489
489
461
0”
-4
“.
123
123
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
124
124
124
124
124
Cl0
124
OH
N,
Cl
Cl
Cl
124
124
CN
AN
124
I24
AN
124
Cl
NO,
NO2
NO2
123
124
124
123
123
123
123
123
123
123
123
1
1
123
Ww9
123
123
1
1
2
2
Ru(bpY) 2
Ru(bpY) 2
(PVP):’
(PVP)(OH)+
ROPY),
Ru@pyh
(PVPXN,)+
Ru(bpy) 2
(PvP)(cI)+
Ru(bpy) 2
(PVP)(Cl) +
Ru(bpy) 2
(PvP)(cl)+
Ru(bpYh
(PVP)(CN) +
Wbpy) z
(PVP)(AN)* +
Ru(bpy) 2
(PVP)(AN)* +
Ru(bpy) 2
(PVP):’
(4-vpyXN4)’
Ru(bpy) z
(PVP)(CI) +
W’py)
t4-vp~XNO2,’
R@PY),
wpY):+
Ru(bpY) z
FvpY):+
Rutbpy) 2
@-vpY):+
Ru(bpy) 2
WPYMNW’
Rdw) 2
wPY):+
R4b-v) 2
wPY)22'
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
SSCE
AN
SSCE
SSCE
SSCE
AN
AN
AN
AN
AN
SCE
SSCE
SSCE
SSCE
H2O
SCE
H,SO,
AN
SCE
SSCE
1M
AN
AN
SSCE
SCE
AN
CH,CI,
SSCE
SCE
AN
H2O
SSCE
AN
SSCE
SSCE
AN
AN
SSCE
1M
HCIO,,
AN
SSCE
Ref.
Solvent
SCE
SSCE
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
Stand.
945
1240
240
570
700
640
760
990
1135
1240
1240
760
910
1030
1035
1225
1220
1250
1045
1240
E,,,
- 1390
- 1480
- 1455
-1360
-1360
-1355
E,
2030
Eo-0
ox
-790
*E
640
*Gd
-
polymer film
% = E/p,a
polymer film
polymer film,
E,, = E/w
poiymer film
E,, surf.
polymer film
Notes
453
364
364
364
475
453
364
364
453
364
126
455
455
455
45s
455
478
418
455
455
Ref.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
1
1
1
1
1
1
138
138
138
138
138
137
137
136
135
134
133
132
132
131
130
129
128
127
125
124
124
124
NO3
NO2
138
NO
Cl
137
137
Cl
Cl
134
133
132
Cl
131
130
129
128
127
125
NO3
NO2
W
Ru(bpyh
(N-Me-PY):+
Ru(bpy),
(pymXC1) +
Ru(bpy),
(PY~HXCU~+
Wbpy),
(pyd):+
Ru(bpy),
(pyd):+
Ru(bpy),
(PYw1) +
Ru(bpy),
(PY~MNO)~+
Ru(bpy) 2
(PYr):’
Ru(bpy) 2
(pyrXN4)+
fWbpy) 2
(PY’KNO,)+
Ru(bpy),
(p-fum):+
Ru(bpy),
wPYw~+
Ru(bpy),
(p-CH2-cinn):+
Ru(bpyh
(m-cinn):+
Ru(bpy),
(p-&In);+
Mbpy) z
(4’~CN-stylb):+
Ru(bPy) 2
(4’-OMastylb);+
Ru(bpy),
(4’~Cl-stylb);+
Wbpy),
(t-stylb):+
Ru(bpy),
(PVP)(NO,) +
fWbpy1,
(PVP)(NO,) +
(PVP)(H20)2+
Ww),
AN
AN
AN
AN
AN
AN
AN
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
- 920
780
_
1000
1140
k., = E/w
464
464
459
464
570
1510
510
210
880
1240
318
1420
490
448
448
490
- 1380
455
polymer film
448
448
448
448
448
448
_
Pot. py-bound
isomer
_
448
364
364
364
970
840
- 1390
-1400
1220
1220
- 1390
- 1480
- 1380
- 1390
-1400
-1390
- 1380
- 1360
1260
760
1280
1190
1250
1190
1220
1230
900
1050
730
s
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ligands
151
150
149
149
148
148
147
147
146
145
145
145
144
144
144
143
142
141
140
151
150
149
Cl
148
Cl
147
147
146
145
145
145
145
144
144
(a) Mononuclear complexes
TABLE 3 (continued)
-@PY) 2
vwt+
W-JPY) 2
0@,
Wbpy) 2
w:+
Ru(bpy) 2
(PVI)(Cl) +
Ru(bp~) 2
(vi&’
IWPY),
(NMI):+
Wbpy) z
@MI):+
IWPY) 2
(viz)(cl)+
Rucbpy)z
WW;+
RU@PY)~
(imid);+
W-Q:+
R@PY),
(PZI2
Ru(bpy),
@x)2
R@PY)Z
(pzxPzH)+
Ru(bpy),
WV:+
cis-Ru@py) 2
R@PY),
(2,7-dmnapy)2+
R~PY),
(naPyY+
IWPY),
@PM2+
R@PY),
(2-m-napy)*+
Complex
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
Solvent
SCE
SCE
SCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
Ref.
SCE
SCE
SCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
Stand.
1130
450
1000
670
1050
680
940
940
1020
1180
1180
1180
690
300
300
1320
1250
1320
1260
E,,
- 1490
- 1650
- 1480
-1520
- 1520
-1500
,I$_,
Eo-0
- 1020
*E
ox
480
*Ld
in DMSO 222
412
472
472
472
318
210
318
367
450
222
367
367
222
458
458
458
458
Ref.
- -.
Ed in DMSO 222
E,
-
_
E,,-tram
1110 mV
_
Notes
.--...
2
0
“..“
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
173
171
169
166
165
163
162
161
161
160
160
160
160
160
160
159
159
159
15b
153
152
161
161
160
160
160
160
Cl
Cl
159
Cl
Cl
154
153
152
Ru(bpy)z
(PBzimH)‘+
fWbpy)z
(PYmQ*+
Wbpy) 2
(PimH)”
Wbpy),
(phedi)2+
R@PY),
(opdi)2+
Wbpy),
(DPAH)’ +
Wbpy),
(DPA)+
Wbpy) 2
w2):+
Mbpy),
w2):+
Wbpy) 2
(BPE);+
Wbpy) z
(BPE);’
Wbpy) z
(BPE):+
Wbpy) 2
(BPE);+
Mbpy) z
(BPE)(Cl)+
~WPY),
(SPE)(Cl)+
Wbpy) 2
(SPA);+
Wbpy) 2
(3PA)(Cl)+
Mbpy) z
(lIPA)(
RU@PY)Z
(All-tn);+
~W’PY) 2
(Ph-trz);+
fw9PY) 2
(m-t@:+
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
SCE
SCE
1140
1170
1250
1280
irr.
720
30
1320
1330
1240
1290
1310
1300
780
780
1290
770
770
1010
1050
1ooo
N4 +
SCE
SCE
Fc+/O
Fc+/O
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SCE
SCE
SCE
SCE
Ag/Ag
NHE
NO3 *
Ag/Ag
NHE
NO3 *
Ag/Ag
NHE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SCE
SCE
SCE
SCE
-1490
- 1520
- 1250
- 680
-500
- 1780
- 1890
-1300
-1360
- 1350
- 1470
- 1480
-1460
l
l
Wbpy):+/
+ 1260 mV
Ru@py):+/
+126OmV
368
368
239
40
40
235
E, = E/w
235
-40°C,
478
478
478
E, = E/iv
-40°C,
E,, surf.
E,, surf.
478
459
448
510
358
459
510
358
222
222
222
E
CI
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
210
209
208
207
206
205
203
185
184
182
182
181
181
180
179
179
176
1
1
2
SCE(H20)
AN
AN
AN
AN
AN
SCE
SCE
SCE
SCE
SCE
SCE
SCE
AVAgNO,
HNO3
AN
CH,Cl,
SCE
1M
SCE
SCE
AN
AN
SCE(H20)
SCE
SCE
AN
AN
AN
SCE
SCE
AN
SCE
HClO,
AN
Ref.
AN/
Solvent
AN
RuWyh
(EtTROCOZEt) +
AN
Ru@PY),
(EtTRONOZ)+
Ru(bPy),
(EtTROCl)+
R@PY)~
(EtTROH)+
Ru(bPy) 2
(EtTROMe)+
Ru(bpy) 2
(OBzimH)+
R@PY) 2
(NPP)+
R~(~PY)2
@Y&PY)2+
R~@PY)2
(hPY)2+
R@PY) 2
(@Y)2+
R@PY) 2
(M+Y)~+
R@PY) 2
(M~AvY)~+
R@PY) 2
(hPY)2+
Ru(bpy) z
(pmth)”
R@PY) 2
(BiBzimH2)2t
R~@PY),
(BiBzimH2)’ ’
Ru(bPyh
(biimH2)2+
(biimH2)‘+
Ww9
1
1
176
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
SCE
SCE
SCE
SCE
SCE
SCE
SCE
NHE
NHE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
Stand.
360
280
250
220
160
390
766
1282
1260
1600
1600
1603
1600
1220
1120
1110
1040
930
E,,
- 1670
- 1266
- 525
- 520
- 520
- 520
-1600
-1660
Ed
2010
Eo-0
OX
-750
lE
l‘Gd
_
371
_
“_..
.--.. I_....
439
439
439
439
439
368
514
370
452
432
452
432
369
368
485
368
360
Ref.
_
Notes
s
“..“
212
216
217
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
231
230
229
228
227
226
225
224
223
222
221
220
219
218
215
214
213
211
1
1
AN
AN
AN
RWpy),
(e2) +
R@PY)~
@I)+
Ru@PY),
(He])”
R~PY),
(HyamNO2)‘+
(H~arnH)~+
SCE
SCE
SCE
SCE
AN
AN
AN
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
830
990
900
- 210
- 270
-300
420
-1440
-1400
-1640
- 1650
- 1650
-1590
L,
= WP,C
-1590
370
434
434
434
442
442
442
442
442
442
-1500
350
442
442
442
442
442
442
442
-1590
- 1630
- 1620
- 1620
- 1610
-1630
439
439
439
439
439
-1590
340
330
450
390
370
350
350
440
SCE
SCE
410
320
290
250
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
AN
AN
R~PY),
(PhenTROC02Et)+
AN
R@PY),
(PhenTRON02)+
AN
R@PY)Z
(HHyamOMe)+
AN
Ru(bpy)z
(HHyamMe)+
AN
R~PY),
(HHyamH)+
AN
Ru(bpy),
(HHyamCl)+
AN
R~(~PY),
(HHymNO2) +
AN
R@PY)Z
(MeHyamOMe)+
AN
Ru@PY)~
(MeHyamMe)’
AN
R~PY),
(MeHyamH)+
AN
R@PY)~
(MeHyamCl)+
AN
R~@PY)z
(MeHyamNOZ)+
AN
R~@PY),
(HyamOMe)2+
AN
Ru(bpy),
R@PY),
(PhenTROCl)+
Ru(bpy)2
(PhenTROH)+
R~PY),
(PhenTROMe)+
z
w
233
234
236
231
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
251
250
249
248
246
246
246
245
244
242
241
240
239
238
235
R4-w) 2
232
1
1
SCE
SCE
AN
AN
AN
Ru(bpy)z
w+
R@PY) 2
(He5)”
AN
AN
AN
AN
AN
DMF
AN
AN
AN
AN
AN
Ru(bpy),
AN
(DMCH)2+
Ru(bpy),
(DHCH)2+
Ru(bpy),
(MPCH)2+
Ru(bpy) 2
02+
R@PY)Z
W2*
Ru(bpy),
W2+
R~@PY),
(MMCH)2”
R@PY),
(e7)+
Ru(bpy),
W)’
Ru(bpy) 2
(pia2+
R~PY) z
(hpiq)‘+
R@PY),
W’
R~@PY)z
(He6)2+
AN
SCE
AN
R@PY),
w)+
R@PY),
(He4)2+
*
*
A&‘AgNO,
Ag/A.sNO,
Ag/ABNO,
AUAgNO,
Ais/ABNO, *
SSCE
Ais/AgNO,
AUAisNO,
SCE
SCE
SCE
SCE
SCE
SCE
R@PY) 2
(He3)‘+
R@PY) z
(e3)+
AN
SCE
AN
SCE
Ref.
Solvent
AN
(Hc2)‘+
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
HNE
NHE
NHE
NHE
NHE
SSCE
Fc+/O
NHE
NHE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
Stand.
1255
1310
1295
1260
1300
1270
1250
1270
1050
830
960
840
1010
850
1030
820
980
930
960
E,,,
-1000
- 910
- 895
- 1030
-1110
-1135
-1530
-1170
Irr.
- 1580
-1600
-1570
- 1540
-1640
Ered
1900
1880
1870
Eo-0
cw.
-600
- 630
-600
*E
no
710
*&d
= E/m
l
+ 1260 mV
Ww):+/
* Ru@py):+/
t 1260 mV
at -54OC.I
t 1260 mV
* Ww):+/
E, = E/PVC
Era,= E/w
4,
Em,= E/w
Notes
239
239
239
239
40
413
413
40
40
434
434
434
434
434
434
434
434
434
434
434
Ref.
l-...I-_..
h)
z
“..
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
267
261
266
266
265
261
260
259
259
257
257
257
256
255
255
254
253
252
251
251
AN
AN
DMF
AN
AN
AN
AN
AN
AN
Wbpy),
(dpp12+
Wbpyh
(dpp12+
AN
AN
Ru(bpy),
AN
(DB*+
AN and
Ubpyh
(Mebpy-XMJ DMF
+2)4+
AN and
Wbpy),
DMF
WebY3DQ+2)4+
DMF
Wbpy),
(Me-bpy-3DQ
+2)‘+
Wbpyh
(H2por)2’
Wbpy),
(i-biq)2’
R~(~PY),
(i-biq)2’
Wbpyh
(biq)”
Wbpy),
(biq)2’
RWPY)~
(dinvY12’
Wbpyh
(biq)2+
RWPY),
AN
(OMCH)2+
R~(~PY),
AN
(OMCH)‘+
Wbpyh
AN
(TPCH)2+
Wbpy),
AN
(TMCH)*+
WJPY)~
(DF’CH)”
Wbpyh
AN
(DMCH)‘+
(DMCH)2+
Ru(‘wh
SCE
A&‘AgCl
SCE
SCE
SCE
SCE
SCE
W4W3
WWJO,
*
SCE
NHE
SCE
SCE
SCE
SCE
SCE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
1310
1580
1240
1240
1240
1240
1160
1220
1220
1330
1330
1330
1220
1270
1275
1290
1240
1300
1250
1250
- 1060
- 1290
- 1290
-1290
- 1020
- 1510
- 1380
- 1380
-910
- 910
-905
- 710
- 1650
-1645
-990
- 1080
-905
-1Occl
-1000
2120
1700
1700
1670
1720
1720
-900
- 370
- 370
-400
- 410
- 470
740
790
790
20
720
720
= DMF
..“,.^“l_
.._.._
“_..
403
103
506
444
Ed = DMF
E,,, = AN,
E,
444
243
491
40
131
344
40
239
514
40
239
239
239
239
40
E,, = AN,
* Wbpy): +/
+ 1260 mV
* Wbpy):+/
+ 1260 mV
* Wbpy):+/
+1260 mV
-
+ 1260 mV
* W’w): +/
329
2
VI
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
EDP
EDP
EDP
ECN
DAM
DAC
CN *
Bit
BBB
ADP
2SD
2sc
2SB
2SA
215
210
ECN
CN *I
Wbpy)2
(BBB)(Cl)+
Cl
WTY),
(EDP)2+
Wbpy),
(EDP)2+
WVY),
WV:+
W’TY)~
(EDP)2+
WJPY),
(DAM)2+
R~(~PY),
(DAq2+
R~(~PY),
((CW
ww;+
W’PY),
(Bit)‘+
Ru(bp~)2
(ADP)(Cl)+
Cl
W’JPY),
(2SD)2+
Ru(bp~),
(2Sq2’
R~(~PY),
(2SB)2+
Wbpy),
(ZSA)”
R@PY);+
(diffn)
W’JPY) 2
(BL3)2+
AN
AN
AN
AN
AN
AN
DMF
AN
AN
AN
AN
AN
AN
AN
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
Ag/AgN’%
SSCE
SSCE
1
Wbp~),
(BL2)2+
AN
1
1
269
SSCE
AN
(BL1)2+
W’w),
1
1
268
Ref.
Solvent
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
NHE
SSCE
SSCE
SSCE
Stand.
1740
1750
1750
1530
990
960
860
1900
810
1010
1540
1500
1410
1430
1430
1410
1420
1410
E,,,
- 1280
-1500
- 1320
- 1330
- 1250
- 1280
- 1280
- 1280
- 595
- 720
- 420
- 780
Ed
2310
Eo-0
ox
1450
*E
810
*&Cd
= irr.
_
Pt( dien)
CN * is(CN)
Erd = irr.
E,
_
_
-
Notes
462
457
456
492
495
495
325
462
456
456
486
486
486
486
514
372
454
454
Ref.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
NH,
NH3
NH3
NH,
NH,
NCS
Mpc
MeP
MeP
MPP
MPP
MPP
MPP
MPP
MPP
MMP
MDP
MDP
Hz0
For
EDP
NH,
NH,
NO
NO
NO
NCS
MeP
Cl
MPP
MPP
MPP
MPP
MPP
Cl
MMP
Hz0
co
2
Rutbpy),
(NH,);+
Rutbpy) 2
(NH&+
Rdbpy),
(NH,)(N0)3+
Ru(bpy) z
(NH,)(N0)3+
(NHJ)(N0)3+
Ru(by)
WCS),
Ru(bpy) 2
(Mpc)*+
Ru(bpy) z
RuIbpy) z
(MeP):+
Ru(bpy) z
(MeP)(Cl)+
tronr-Ru(bpy)z
(MPP)$+
cis-Ru(bpy),
(MPP);+
(MPP);+
Ru(bpy
)z
Ru(bpy) 2
(MPP):+
cis-Ru(bpy) 2
(MPP);+
Ru(bpy) 2
(MPP)(Cl)+
Rutbpy) 2
(MDP)*+
cis-Ru(bpy) 2
(MMP):+
(Hz@:+
Ru(bpy) z
(MDP)”
Rdbpy),
(For)(CO) +
cis-Ru(bpy) z
(EDP)”
W-w),
DMF
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
H2O
AN
AN
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SCE
SCE
SSCE
Fc+/O
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SCE
SCE
SSCE
270
1268
300
360
360
670
1980
1510
940
1550
1460
1500
1520
1520
910
1450
1630
1630
630
1440
1750
- 1930
- 1350
-480
- 480
- 1340
- 1320
- 1280
-1300
- 1330
- 1330
- 1290
- 1290
- 1320
-1280
- 750
-800
-640
1020
960
1110
Erej= E/P,c
-
-
1390 mV
E,,-tram
456
470
469
464
441
488
489
462
456
456
210
210
456
450
318
450
1330 mV
Erd = irr.
479
456
450
479
210
IT,,-tram
46OmV
E,,,-tram
_
-
E
4
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
+
1
1
PEA
PEA
PDP
PDP
PDA
PCN
PAS
ON4
ON2
NO2
NO2
NO2
NH3
NH3
NH3
NH3
NH3
PEA
ECN
Cl
Cl
PCN
Cl
Cl
Cl
NO2
NO
NO
NO3
N4
NH,
NH,
NH,
(=A):+
WJPY) 2
(Pl%4)(ECN)2+
Wbpy) 2
R~PY) 2
(PDP)(CI)+
WTY),
(PDP)”
Wbpy) 2
ww:+
R~@PY),
(PDAXCl) +
R~PY),
(PAs)(Cl) +
R@PY),
(ON4XCl) +
(ONZXCI) +
R@PY),
W2)2
R~JPY),
wMNo)2+
Ru@PY)~
PJ4XW2+
WJPY)~
fWXN4)’
WVY),
WH,XNW
Wbpy),
(NW:*
W’JPY),
(NW:+
R@PY),
(NH,)?
R~@PY),
2
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
H2O
AN
AN
AN
1
(NH,);+
W’w)
(NW:+
1
NH,
1
1
NH,
AN
WW),
NH,
1
1
NH,
Solvent
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
Ag/Ag+
SCE
SSCE
SCE
SCE
Ref.
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
SSCE
s ref
SCE
SSCE
SCE
SCE
Stand.
1040
1260
910
1620
900
1520
930
1230
1240
1258
330
330
700
850
580
910
920
1255
1280
E,,
- 1310
-‘1300
-1290
- 1350
- 1355
-560
-560
- 1480
- 1353
-1340
Erd
Eo-0
*E
ox
*&I
= irr.
Ed = irr.
E,
Erd = irr.
E,, = E/p-a
E,, = E/w
Em, = E/PVC
4, = E/p,a
Notes
.._....-._.**“-..
492
492
456
456
456
492
456
461
461
469
441
488
464
464
317
501
495
477
474
Ref.
PPP
PPP
PPP
PPP
PPP
PRC
PSb
SEE
SMM
SMM
SNA
SNB
SNC
SND
SNE
SNO
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
SSB
SMP
PPP
PPP
PMA
1
1
PMA
1
1
Cl
SMM
SMM
Cl
Cl
PRC
SEE
PPP
NO3
N4
NO
Cl
Cl
PMA
PCN
mw:+
2
Ru(bpy),
(SSB)+
Ru(bpy) 2
(SN0)2+
Ru(bpy) 2
(SNE)+
R@PY) 2
(SND)2+
Ru(bpy) 2
(SNC)*+
Ru(bpy) 2
(SNB)2+
R~@PY),
(SNA)2+
c*Ru(bpy),
(SMP)(Cl) +
R@PY) 2
(PSb)(Cl)+
cis-Ru(bpy),
(SEE)(a)+
cis-Ru(bpy)l
(SMM);+
mm-Ru(bpy) 2
(SMM);+
R@PY) 2
(PRC);+
R@PY) 2
(PPP);’
cis-Ru(bpy) >
(PPP)(SEE)‘+
Ru(bpy) 2
(PPP)(NO,)+
Ru(bpy) 2
(PPP)(NO,)+
Ru(bpy) z
(PF’P)(NO)3+
Ru(bpy) 2
(PPP)(Cl) +
R@PY),
(PPP)(CI) +
Ww)
(PMA)(PCN)*+
Wbm) 2
SSCE
SSCE
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
AN
AN
AN
AN
AN
AN
AN
PC
PC
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SSCE
SSCE
SSCE
540
300
1380
880
1370
1420
880
930
1480
1550
1540
1070
1250
560
940
940
1040
1290
464
464
486
486
- 1250
-1530
486
486
486
486
486
_
486
486
486
456
486
= in.
_
E,
492
Diss. D.J.
462
Salmon, 1977
486
E ox = E/pa
464
479
456
-1490
-1280
- 1380
-1340
-1360
-1500
-1310
-1490
- 1370
- 1280
-1460
-1290
492
492
W
E
SSM
1
1
1
1
1
1
1
1
1
1
1
13
13
15
17
26
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
26
17
15
13
13
nor
nor
ipp
SlY
dmp
dia
aca
aca
aca
SSO
Wbm),
SSE
1
1
+
+
AN
bpy):’
Ru(bpy)
(4,4’dph-
bPy):+
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
AN
Solvent
bpy):+
R@PY)
(4,4’-dBr-
R~@PY)
(4,4’-dm-
bpY):+
bpy):+
Ru(bpy)
(3,3’-dm-
R~@PY)
(3,3’-dm-
cis-Ru(bpy)z
(nor) 2+
R~@PY),
(nor) 2 +
(W’
R+PY)~
(gly)+
Ru(bpYl2
(dmpJ2’
W’JPY) 2
R~(~PY),
(d#+
(aca) +
Wbpy),
(a4
Wbpyl,
(4
Ru(bpY),
(SW+
wbY)2
PM)+
W’PY~,
(SSE)+
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 3 (continued)
1180
NHE
Ag/Ag
NO3
Ag/Ag+
AdAg+
NHE
s ref
s ref
1220
1080
900
1180
1700
1700
800
‘673
1400
1450
620
603
610
740
540
550
E,,
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
Stand.
NHE
Ag/Ag
NO, *
Ag/Ag
NO,
SSCE
SSCE
SCE
SCE
SSCE
SSCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
Ref.
- 1690
- 1410
- 1410
- 1530
- 1380
- 1360
- 1550
- 1563
- 1480
- 1530
- 1520
-%d
2100
2100
Eo-0
- 870
- 920
- 920
-830
-800
- 1070
*4X
690
690
850
890
*J%d
_
E,=in
(bpy): +
/+1260
mV
* Ru
E,, =
Eha
-
_
-
-
Notes
..“.I”____
..--.
224
307
307
40
329
497
462
468
469
210
210
477
469
467
486
486
486
Ref.
K
0
26
26
30
30
38
54
59
59
59
61
67
68
CN
CNCN
en
108
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
108
en
CN
68
67
61
59
59
59
54
38
30
30
26
26
AN
bpy):+
R~@PY)
(4,4’-DTB-
(CN):Ru(bpy)
(en):+
Ru(bpy)
(DIAFO);+
AN
H2O
DMF
s ref
SCE
Ag/Ag
NHE
NO, +
Ag/Ag+
SCE
SCE
SCE
H2O
(CN):CN CN Ru(bpy)
SSCE
SSCE
AN
SSCE
SSCE
Fc+/O
SSCE
NHE
NHE
NHE
NHE
SSCE
Ag/Ag
NHE
NO, *
SSCE
SSCE
SSCE
NO3
Ag/Ag
Ag/Ag
Cl
NO, l
AU&
NO3
A8/Ag
SSCE
Fc+/O
AN
AN
AN
DMF
AN
AN
Ru(bpy)
@hen):’
CN CN Ru(bpy)
bpy):+
R~(~PY)
(bpz):+
R@PY)
(bPz):+
Ru(bpy)
(bpz):+
Ru(bpy)
(bpym)22+
Ru(bpy)
(h-phen);+
bpy):+
Ru(bpy)
(6,6’-dm-
Ru(bpy)
(4,4’-DCI-
CH,C12
AN
bpy):+
R@PY)
(4,4’-DTB-
bpy):+
AN
DMF
bpy):+
Ru(bPY)
(4,4’-dph-
(4,4’-dph-
W’w y)
1310
260
200
780
1300
1210
1550
1713
1720
1185
1160
1160
1203
Ru
at
-54OC
(bpy):+
/+ 1260
mV
l
_
514
447
40
329
- 680i
- 1950
2160
- 850
-1500
* Ru
(bpy): +
/+1264l
mV
* Ru
(bpy):+
/+1260
mV
40
317
222
222
458
40
229
- 950
- 1370
473
- 805
473
750
710
710
- 1270
-910
-940
-940
473
473
229
2120
2100
2100
at
-54OC
-790
-1400
- 480
-1390
-1390
-1298
-1710
5
109
109
110
111
120
124
124
127
156
160
162
163
164
180
181
181
181
182
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ligands
182
181
181
181
180
281
163
162
281
281
281
281
281
281
281
110
109
109
(a) Mononuclear complexes
TABLE 3 (continued)
Ru(bpy)
+
(ipaKtrpy)
Ru(bpy)
(pydipy)?
Ru(bpy)
WPYI22’
Ubpy)
(hPY):+
Ru(bpyI
(hPY):+
Wbpy)
(Mehpy) $’
R~@PY)
(DPA),
Ru(bpy)
(DPAH);+
t~PEXtrpy~2+
W~PY)
wwPY)2+
Ru(bpy)
Wbpy)
(PYwPY)2 +
Ru(bpy)
(4-vpYxtrpY)2’
Ru(bpy)
(pVPXtrpY)2+
W~PY)
(pVPXtrpY12+
Ru(bpy)
(4’-CI-stylb)(trpy)2 +
W~PY)Z
(phen-dione)i+
Ru(bpy)
(taphen):*
(taphen):+
Ru(by)
Complex
AN
H2O
CH,Cl,
AN
SCE(H
Ww):
SCE(H,O)
SCE
20)
+
SCE
SCE
SCE
SCE
SSCE
AN
AN
Fc+/O
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
NHE
Fc+/O
SSCE
SSCE
*
NHE
Stand.
AN
AN
SSCE
SSCE
CH,CI,
AN
SSCE
1,2-dme
SSCE
SSCE
AN
AN
SSCE
SSCE
AN
AN
Ag/AgNO,
Ag/AgNQ
AN
AN
Ref.
Solvent
1890
170
1880
1210
720
510
- 410
1210
1190
1210
1300
1210
1210
1210
1430
1480
1480
E,,
-210
-70
- 210
- 1820
- 2060
- 1260
- 1350
-1260
- 1260
-160
-740
-740
E,,
1770
1930
Eo-0
01
- 450
*E
1190
*&d
= -%‘w
trans/cis
trans/cis
E,
-4O”C,
-40°c,
E, = E/P,c
Diss. D.J.
Salmon, 1977
* Wbpy): + /
+126OmV
Notes
432
376
375
432
369
503
235
235
448
317
448
374
374
448
374
480
40
238
Ref.
g
h,
182
184
185
246
246
251
251
251
256
257
251
251
259
259
281
281
281
281
281
281
281
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
NO
Cl
CN
CN
CN
CN
AN
259
259
257
257
251
256
251
251
251
246
246
185
184
182
W~PY)
(tQYNAN)2+
W~PY)
WyXCN)+
Wbpy)
(trpYXW +
Wbpy)
(trpyXCN)+
Wbpy)
@PYXCN) +
Wbpy)
@PYXCl)+
Wbpy)
(trpy)(NW3 +
Wbpy)
(i-b@:+
W~PY)
(i-b@:+
Wbpy)
(bapy):+
Wbpy)
(bw:+
Wbpy)
@is>:+
W~PY)
(biq):’
WlJPY)
(DMCH);+
Wbpy)
(DMCH);+
WbPY)
(Mehpy)?
Ubpy)
(&PY):+
Wbpy)
(PmtG’
RU@PY)
02+
WJPY)
0:’
Wbpy)
(DMCH);+
l
AN
AN
SSCE
Ag/AgN’& *
Ag/AgNO,
AUAgNO,
AN
DMF
Ag/AgNO, *
AUAisNO,
AN
DMF
SSCE
Ag/W’JO,*
AN
AN
W&NO,
Ag/AgNO, *
AtiAisNO,
Ae/AgNO,
Ag/AgNO,
AUAW,
Ag/AgNO,
SSCE
AUAgN4
SCE
SCE(H20)
AN
AN
AN
AN
AN
AN
AN
AN
AN
DMF
1M
HNO,
AN
AN
1050
*
SSCE
450
810
1030
*
NHE
1080
1080
*
NHE
1310
1170
1170
1400
1400
1395
1130
1250
1250
1255
1300
1298
1270
1920
SSCE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
NHE
SSCE
Fc+/O
NHE
NHE
SCE
-200
- 1350
- 1390
-1440
-1330
- 1330
- 1420
- 1420
- 820
-820
- 820
-640
- 920
- 920
- 920
- 1075
-1490
- 1254
- 230
1790
1980
2120
1690
1690
1680
1680
2010
- 980
-900
-860
-950
-290
-290
-430
-430
-740
440
650
610
700
870
870
760
760
* Wbpy):*/
+ 1260 mV
* Wbpy):*/
+ 1260 mV
* Wbpy):+/
+ 1260 mV
* Wbpy): +/
+ 1260 mV
* Wbpy):+/
+ 1260 mV
* Wbpy):+/
+ 1260 mV
* Wbpy) :+ /
+ 1260 mV
-
* Wbpy):+ /
+ 1260 mV
-
at -54OC
cis/cis
441
40
221
221
40
221
377
40
131
344
40
239
514
40
329
239
473
473
514
370
432
K
Ld
NH,
nor
2
3
I
7
7
I
7
I
1
1
2
3
1
I
7
I
1
I
Cl
Cl
7
7
7
7
I
3
2
NH,
Cf
Cl
Hed
1
NH,
NH3
281
1
NH,
IPA
281
1
IPA
281
1
AN
AN
AN
AN
AN
AN
AN
bpy):+
Ru( 4-Brbpy):+
Ru(4-nbpy);+
Rll(Cnbpy):+
RI&@-t&
bpy):+
Ru(dnbpY):+
Ru(Qnbpy):+
cis-Ru(4(Q2
n-bpY),
Ag/AgNO,
SCE
Ag/AgNO,
Ag/AgNO,
SCE
SCE
SCE(H,O)
Ag/AgNO,
SCE
SCE
AN
AN
Hz0
SSCE
SCE
AN
AN
SSCE
SCE
* NHE
NHE
SCE
SCE
SCE
NHE
NHE
SSCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
Stand.
Ref.
AN
AN
4.68
Hz0 PH
Solvent
R~@PY)
WpY)
(NHJ)~+
Ru@py)
(Hed)
R@PY)
(NH,):+
RGpy)
(noWh
Ru(4-Cl-
Ru@py)
0rpY)
(iPA)‘+
(IPA)‘+
WY)
Wm)
(WY)
(NO)'+
Ww)
281
1
NO
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
850
1550
1550
1540
1540
1540
1340
1330
1040
510
330
1170
1080
120
E,,
-550
- 545
- 630
-630
- 1710
-600
- 1230
190
Ered
1930
Eo-0
OX
- 380
- 420
-740
- 750
*E
1138
*-Cd
= irr.
* Ru@py):+/
+ 1260 mV
_
E,
E,=E,=irr
_
Notes
431
40
239
431
378
378
224
224
497
501
481
501
503
493
253
Ref.
F
9
9
9
9
13
13
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
9
9
9
9
13
13
15
15
15
15
15
15
15
15
15
15
15
15
15
15
15
AN
AN
AN
by):+
Ru(3,3’-dmRu(4,4’-dmby):+
Ru(4,4’-dm-
AN
W
AN
by):+
Ru(4,4’-dmby):+
Ru(4,4’-dm-
15
15
0.5M
AN
EtOH
CH,Ci,
AN
by):+
Ru(4,4’-dmby): +
Ru(4,4’-dmby): +
Ru(4,4’-dmby):+
Ru(4,4’-dm-
15
15
15
15
15
by):+
DMF
by):+
Ru(4,4’-dm-
15
H2SO4
I-W
brv):+
Ru(4,4’-dm-
15
by):+
Ru(4,4’-dm-
15
‘w):+
Ru(4,4’-dm-
AN
‘w):+
Ru(4,4’-dm-
15
15
by):+
Ru(4,4’-dm-
AN and
DMF
DMF
SCE(H,O)
AN
brW,(Cl):+
Ru(3,3’-dm-
‘w):+
Ag/AgNOj
AN
hW:+
Ru(6tep-
15
Cl
AN
bw):’
Ru(4-tep-
b/b+
SC&H,01
SCE
SCE
SCE
SCE
A8/AgND,
SSCE
SCE
WhW’,
Ag/AgND,
SCE
SCE
SCE
AN
‘w):+
Ru(4-tep-
SCE(H,O)
AN
Ru(Ctep-
by):+
Ru(4,4’-dm-
15
15
13
13
Cl
‘9
9
9
l
s ref
SCE
SCE
SCE
NHE
SCE
NHE
SCE
s ref
SSCE
SCE
NHE
SCE
NHE
NHE
SCE
SCE
SCE
SCE
810
1100
850
1100
1100
1100
1093
1165
1130
1110
1140
1150
1150
750
1520
1520
1520
- 1760
- 1460
-1440
-1340
-1370
- 1450
-1370
- 1470
-1940
- 1336
- 1370
-1460
-1460
- 960
-960
2270
2040
2040
1980
2080
2080
-940
- 850
- 950
-940
- 930
- 930
- 480
690
640
690
670
620
620
RuUW:+/
+126OmV
Ed = DMF
E,, = AN,
l
/6+
E oxcx= 5 +
169
509
60
176
232
12
469
465
69
444
224
149
4c
329
431
431
378
37%
AN
bpy) 2(4,4’DCE-bpy)’ +
Ru(4,4’-drn-
15
15
15
17
37
16
16
16
16
17
17
21
22
23
15
15
15
15
15
16
16
16
16
17
17
21
22
23
23
22
21
17
DEO-bpy);+
Ag/AgNO,
AN
Ag/AB+
AfUAgNO,
Ag/AgNO,
AN
bpy):+
Ru(4,4’-dBr-
17
AN
AN
bpy):+
Ru(4,4’-dBr-
16
WAgNO, *
Ag/A&NO,
AN
bpy):+
Ru(4,4’-dCI-
Ag/AgNO,
Ag/AgN4
SCE
Ag/Ag+
SCE
Ag/AgNO,
AN
AN
bpy):+
Ru(4,4’-dCl-
bpy):’
Ru(4,4’DEA-bpy);+
Ru(4,4’BAA-bpy):+
Ru(4,4’-
AN
bpy):+
Ru(4,4’-dCI-
16
16
AN
AN and
DMF
AN
wBbpy):+
Ru(4,4’dCl-
bpyX4,4’-
bpy):+
Ru(4,4’-dm-
bpy) 2(Mebpy3DQ+2)‘+
Ru(4,4’-dmbpy)(4,4’-dBr-
16
37
17
266
61
37
17
AN and
DMF
CHICI,
bpy) 2(4P’dBr-bpy)‘+
Ru(4,4’-dm-
15
15
bpy)z(bpym12’
Ru(4,4’-dm-
AN
bpy):+
Ru(4,4’-dmAUAg+
SCE
DMF
Ru(4,4’dm-
15
15
15
Ref.
Solvent
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 3 (continued)
-1060
-1090
970
900
NHE
- 580
- 650
- 650
- 550
-440
NHE
2070
2070
1890
-1300
-1060
-1060
-1060
- 880
- 1350
- 1520
- 1030
- 1370
610
1140
1440
1420
1420
1425
1440
1440
1030
1120
1300
930
1130
NHE
s ref
NHE
NHE
NHE
NHE
SCE
s ref
SCE
s ref
s ref
SCE
1010
1010
1010
*&cd
= irr.
Z& = irr.
* R~(~PY):+/
+1260 mV
-
E,, = AN,
Ed = DMF
E,
E,, = AN,
Ed = DMF
Ed = irr.
Notes
224
224
224
307
224
344
40
239
224
444
307
444
465
135
307
270
Ref.
24
25
26
26
26
26
28
29
30
30
30
33
37
37
37
37
37
37
37
38
24
25
26
26
26
26
28
29
30
30
30
31
37
37
37
37
37
37
37
38
DMF
AN
AN
0.85M
bpy): +
Ru(4,4’-dph-
bpy):+
Ru(4,4’-dph-
bpy): +
Ru(4,4’-dsty-
bpy):+
Ru(4,4’-dc-
26
37
bpy):+
Ru(4,4’-DCE-
bpy),(Mebpy3DQ+2)‘+
Ru(4,4’-DCI-
37
266
38
bpy):+
CHICI
bpy):+
Ru(4,4’-DCE-
CH,Cl,
AN and
DMF
AN
37
ANand
DMF
DMF
DMF
DMF
AN
AN
AN
H,SO.,
AN
bpy):+
Rt1(4,4’-DCE-
37
-bpy):+
Ru(4,4’-DCE
DCE-bpy):+
Ru(4,4’-DCE
DCEbpy):+
Ru(4,4’-
37
Ru(4,4’-
poeg-bp
y):+
bpyX4,4’-
DTB-bpy);’
Ru(4,4’DTB-bpy); +
Ru(4,4’-dnd-
37
33
30
30
30
29
2%
26
bpy):+
Ru(4,4’DTB-bpy); +
Ru(4,4’-
AN
bpy):+
Ru(4,4’-dph-
AN
26
i6
25
AN
AN
Ru(4,4’DPO-bpy):+
Ru(4.4’DBO-bpy): +
Ru(4,4’-dph-
24
Ag/AgCI
SCE
Ag/AgNO,
SCE
SCE
SCE
AUAgN4
AUAisNO,
A8/A8N4
Ais/AgNO,
SSCE
Aw’AgNO,
SCE(H,O)
Ag/AgNO,
Ag/AgNO,
l
NHE
SCE
NHE
Fct/O
SCE
Fct/O
SCE
SCE
NHE
NHE
NHE
NHE
NHE
SSCE
Fct/O
NHE
SCE
NHE
NHE
1430
1550
1560
1540
1540
1040
1110
1110
1110
1560
1140
1188
1200
1200
950
1050
-460
-860
-910
-1340
-890
- 1340
-890
- 1500
-1440
-1440
- 1335
- 1273
-1690
1960
2160
2160
- 470
- 420
- 1080
- 1050
- 1050
- 820
- 880
- 850
- 1070
-940
1070
620
120
720
270
384
40
329
239
504
224
473
473
&,, = DMF
E,, = AN,
441
444
135
224
- 54Oc,
63
E,_, 31= - 2050
444
E,, = AN,
E, = DMF
62
At -54°C
* Ru(bpy): +/
t 1260 mV
-
-
E, - E/P,c
At -54’C
224
149
224
224
38
38
38
39
40
43
44
46
46
46
46
46
46
47
50
50
50
50
50
50
51
38
38
38
39
40
43
44
46
46
46
46
46
46
47
50
50
50
50
50
50
51
Ligands
51
61
50
50
50
50
46
AN
Cl
Cl
41
50
46
46
44
43
40
39
130
38
38
AN
CI
CI
130
(a) Mononuclear complexes
TABLE 3 (continued)
AN
AN
AN
AN
AN/iBN
DMF
bpy):+
Ru(4.4’-DCI-
bpyh(p-cinn)?
Ru(4.4’~DOC-
bpy):+
Ru(4,4’-DCB-
bpy):+
Ru(4,4’-DHC-
bpy):+
Ru(4,4’-DCA-
DMF
0.5 M
bpy):+
Ru(5,5’dm-
bpy):+
Ru(5,5’dm-
bpy):+
Ru(5,5’dm-
AN
DMF
bpy):+
Ru(5,5’-dm-
bpy),tbpym)*’
Ru(5,5’-DCEbpy):+
DMF
bpy):+
Ru(5,5’-dm-
H2S04
AN
RW-bpy) 2(AN) :’
Ru(v-bpy) z(Cl) 2
Ru(v-bpy) 2(Cl) 2
ROB):+
Ru(5,5’-dm-
Ru(v-bpy); +
AN
1M
HCIO,
AN
AN
AN
AN
AN
AN
bpY):+
Wv-bpy) : +
Ru(v-bpy):+
AN
bpy):+
Ru(4,4’-DCI-
Solvent
Ru(4.4’~DCI-
Complex
NO3
Ag/Ag
SCE
SCE
NO3
SCE
NO3
Ag/Ag
SSCE
SSCE
SSCE
SSCE
SSCE
Ag/Ag
SSCE
SSCE
SCE
SCE
SCE
SCE
SSCE
SCE
SCE
Ref.
Fc+/O
s ret
SCE
SCE
SCE
s ref
SSCE
SSCE
SSCE
SSCE
SSCE
NHE
SSCE
SSCE
SCE
SCE
SCE
SCE
SSCE
SCE
SCE
Stand.
1150
920
1160
1350
300
360
1130
1160
1160
925
1280
1350
1560
1560
1460
1590
&..
-1140
- 1530
- 1410
- 1390
- 1980
- 1410
- 1430
- 1430
-1120
-990
- 950
- 910
-960
-900
-900
a%_,,
Eo-0
OX
- 980
*E
lhd
465
270
509
60
465
455
455
455
455
502
224
455
455
270
354
354
354
448
354
380
Ref.
-549c,
63
Bd 51= - 1770
-
Polymer film
Polymer film
Polymer film
Polymer film
_
Notes
7
53
54
52
53
54
55
55
56
59
52
53
54
55
55
56
59
AN
Bf
Cl
Cl
59
59
59
59
59
59
59
59
59
59
60
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
59
I
56
266
55
52
51
51
51
51
51
51
Cl
Cl
Br
Cl
I
AN
AN
AN
bpy):+
Ru(5,5’-BAA-
bpy): +
Ru(S,S’-DCI-
bpy): +
Rll(6,6’-dm-
Ru(bpz),
(W2
Ru(bpzh
(Cl) 2
Ru(W,
(Cl),
Ru(bpzh
(AN)(a) +
Ru(bpz):+
Ru(bpz),
(bpzH)3 +
Ru(bpz);+
Ru(bpz): +
Ru(bpz):+
Ru(bpz): +
Ru(bpz): +
Ru(bpz): +
Ru(bpz):+
Ru(bpz): +
Ru(bpz)i+
Ru@~z),(I)z
Ru(HQbpy): +
Rub-bpyh
(Mebpy
-3DQ+2)4+
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
AN
AN
AN
SCE
SSCE
SCE
SCE
SCE
SCE
SSCE
SCE
Fct,‘O
SSCE
SCE
SCE
AgRE
SCE
SSCE
SCE
Ag/Ag
NHE
NO3 l
SCE
SCE
SCE
NO3
SCE
NHE
SCE
NO3
SCE
Ag/Ag
NHE
SCE
SCE
Ag/Ag
SCE
SCE
SCE
AN
H2D
AN
AN
H2D
AN
AN
DMF
AN
AN
AN
AN
AN
AN
AN and
DMF
AN and
DMF
DMF
bpy):+
Ru(5,5’-DCE-
bpy):+
Ru(tm-bpy)$+
AN
Ru(5,5’-DCE
550
-860
-8cQ
- 280
-990
-1090
-1040
-1040
1320
790
800
800
1930
1860
1860
1860
2270
-100
-990
-260
2050
-900
-280
- 765
- 680
- 680
-800
- 1210
- 743
-800
-800
1895
1980
1980
1860
800
- 1050
-1390
1060
1175
- 1490
-1330
- 720
-660
- 650
1060
1365
1210
1530
1630
1440
1360
1450
1400
560
1240
revers.
Ed = part.
revers.
Ed = part.
revers.
Ed = part.
Same res.
for H,O
At -54°C
Ed = p.rev.
Ru@py):+/
+126OmV
E,,, = irr..
l
E,, = AN,
E, = DMF
E,, = AN,
E, = DMF
.. - .---_.._ll.-...
“_”
436
385
436
385
389
397
387
386
443
229
385
473
473
232
387
436
511
444
444
514
380
224
270
516
63
NH,
63
63
61
63
63
64
64
65
NH,
NH,
261
61
AN
AN
AN
pw:+
Ru(+pyPrim):+
Ru(CpyPh):’
Ru(h-phen):’
64
64
65
65
66
64
64
65
65
66
67
68
68
68
68
68
68
68
68
68
65
66
67
68
68
68
68
68
68
68
68
6%
68
68
68
68
68
68
68
68
68
Ru(phen); +
Ru(phen); +
Ru@hen): +
Ru(phen): +
Ru(phen): +
Ru(phcn); +
Ru(phen); +
Ru(phen):+
Ru(phen);+
AN
AN
bpym):+
Ru(bprid):+
Ru(bprid)$+
Ru@py-
63
67
AN
bpym):+
Ru(6,6’&-
SCE
SCE
AN
AN
H2O
Ag/Agfl
AgRE
SSCE
So,
AN
Ag/AgNO,
Ag/AgCl
Ag/AgNO,
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
Ag/AgNO,
SCE
Ag/AgNO,
Ru(bpy): +
*
*
SSCE
NHE
SCE
SCE
NHE
NHE
sref
NHE
NHE
SCE
SCE
SCE
SCE
SCE
SCE
1030
1300
1260
1270
1400
1260
1270
1400
1200
1380
1380
1580
1580
1380
1490
-1360
-1350
- 1410
-1200
- 1010
-1390
-1040
- 1180
-1000
-1Ooo
- 1180
-780
1870
- 380
2130
2130
2110
2060
-870
- 870
-940
-930
-730
-480
790
850
740
940
930
1060
1060
910
1090
1090
232
- 780
Peak potentials
t 1260 mV
149
224
445
447
438
458
12
232
4
40
-.I.~---..l_ll.-... “_”
* Ru@W:+/
232
487
232
487
232
487
513
1490
SCE
* Ru(bpy):+/
+ 1260 mV
460
- 980
756
232
512
NHE
*Ru(bpy):+/
+ 1260 mV
1452
12ao
Reference
= 1260 mV
436
E,,, = part.
revers.
229
465
361
436
E,, = irr.
*
- 910
- 750
- 910
-1400
- 930
Ref.
Notes
1690
1515
1640
1690
1180
940
l%d
SCE
NHE
SSCE
s ref
NHE
SCE
SCE
SSCE
SCE
SCE
Ref.
AN
AN
CH2Clz
Hz0
AN
HZ0
AN
AN
AN
AN
AN
AN
AN
AN
AN
Solvent
Ru(bpym)
(Dp): +
Ru(bpym)
(NH,):+
Ru(6,6’-dm-
NH,
Ru(bp~m): +
Ru(bpum)
(biq)i+
61
257
61
251
61
61
261
Ru(b~ym):+
Ru(b~ym):+
Ru(bpym):+
61
61
61
61
61
61
61
61
61
WA)2
NO2 N4
59
59
Ru(bpz),
(NCS) 2
Ru(bpz)Z
NCS
59
NCS
Complex
59
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
8
_.
AN
H2O
CN
I
Br
CN
Cl
Cl
N3
111
AN
AN
CN
CN
en
en
en
105
111
111
111
111
111
111
111
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
6a
CN
AN
AN
68
68
68
68
48
68
68
68
68
87
68
68
68
68
68
68
68
AN
DMF
@he@,
(AN)
(HzW2+
Rubhe&
(PYw,)+
Ru(ph+
(PYG
Ru(phen),
@YXU+
Ru@hen),
(PYXB~)+
Rubhen),
(PYXCN)+
Rubhen)
(PYXCU+
Rubha),
@YXCb +
Ru@hen)2
(BDCMP)
Wphen),
w2+
Ru@hN,
w2+
Ru@hW,
&@2+
RWW,
OJ),
Ru(phW2
SSCE
AN
AN
AdA@
Ag/AgCl
Ag/AgCl
AN
AN
Ag/AgCI
Ag/AgCl
AN
AN
AdAi
AgRE
&s/b’
SCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
AgRE
SCE
SCE
AN
AN
H2O
1.5 M
HCl
H2S04
6M
DMF
AN
@ha)2
(AN):+
trawRu
VW2
AN
@ha),
(AN):+
tr4awRu
AN
H2O
AN
AN
Ru@hen),
(4,7X12phen)2C
cis- Ru
Ru(phd+
Ru(phen):+
Ru(phen);+
Ru@hU2);+ H2O
s ref
s ref
SSCE
s ref
s ref
s ref
s ref
SCE
s ref
SCE
SCE
SCE
SCE
SSCE
SSCE
SSCE
SCE
NHE
SCE
SCE
1440
730
182
920
960
940
930
1430
610
a70
800
880
884
1080
1450
1440
1290
1260
1400
- 1350
- 1380
-1390
-1340
- 1370
-1340
- 1520
- 1550
- 1598
- 1220
-1360
- 1410
- 1430
2190
2180
- 870
190
466
445
445
445
445
395
317
4%
4%
176
471
484
484
484
E,, vs/ NHE/
445
Fc+/O=59O
E,, vs. NHE/
445
Fc+,‘O =1290
E,, vs. NHE/
Fc+/O=79O
E,, vs. NHE/
Fc+/O-800
E,, vs. NHE/
Fc+/O-820
E,,, vs. NHE/
Fc+/O=78O
T= 2O.O”C
and E/PC
E = .!?/~,a
-
176
391
169
393
395
123
Cl
111
111
123
138
140
141
142
143
168
246
251
251
262
NH,
68
68
68
68
68
68
68
68
68
68
68
68
68
68
en
en
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
68
en
en
SCN
111
68
68
NH3
NO2
NH,
111
111
68
68
111
111
68
68
Ligands
(a) Mononuclearcomplexes
TABLE 3 (continued)
AN
@Y)Z’
Ru(phen)s
(PYXNHS)”
AN
(PPyz)2+
Ru@fW,
(2-m-napy)’ +
Ru(phenXen):+
(NH&+
Ru(phenXen)i*
Ru(phen),
(9-PDP)2+
Ru@hen) 2
(biq)2+
Ru(P~@,
(DMCH)‘+
W~h@2
W2’
H2O
1.5 M
HCI
H20
AN
AN
AN
AN
Ru@he@,
(2,7-dmqy)2 +
6M
Ru(phen),
(diim)2+
H2S04
AN
NIJ~~),
AN
AN
Ru@hN,
AN
tpyrxCb+
RUO,
(napy)2+
AN
AN
WPJ=-N,
(PYww+
WPWZ
(PYXSW +
WphW,
ePY):+
AN
AN
WPW,
AN
(PYG’
truns-Ru(phen)2
Solvent
cis-Ru(phen)2
Complex
Ag/AB+
SCE
WAg+
Ais’=
Ais/Ag
NO3 *
NO, *
W.%
NO3 *
Ad&
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
Ag/A@
AdA&
Ag/‘A@-J
SSCE
SSCE
Ref.
1300
1290
SCE
NHE
s ref
SCE
s ref
SCE
NHE
290
550
570
1360
1360
1290
1330
SSCE
NHE
1260
1330
SSCE
SSCE
1270
SSCE
860
1250
SSCE
SSCE
- 1050
-1200
1020
1260
1290
E,,
s ret
s ref
s ref
SSCE
SSCE
Stand.
-500
-910
-1000
- 1140
- 1370
- 1320
- 1340
- 1330
E red
1740
1750
1900
Eo-0
-380
-460
-610
+E
ox
830
750
760
*Ed
* Ru(bpy): +/
+1260 mV
* Ru(bpy): +/
+ 1260 mV
+ 1260 mV
* W’w):+/
E,, vs. NHE/
Fct/O-880
I?,,, vs. NHE/
Fc+/O -950
E,,, vs. NHE/
Fc+/0=900
_
484
_
317
496
317
395
40
40
40
496
458
458
458
458
430
448
445
445
445
484
Ref.
Notes
k
86
86
86
86
86
88
88
88
93
99
83
83
84
86
86
86
86
86
86
86
86
87
88
88
88
93
99
83
83
84
86
86
86
86
86
86
86
86
87
88
88
88
93
99
a7
138
86
83
83
84
86
80
80
81
138
79
79
79
79
79
Hed
79
79
79
79
79
80
80
81
81
68
79
79
79
79
79
80
80
81
81
Cl
Cl
phW:+
Ru(4,7-Ph2phen)i +
Ru(4,7-Ph2phen)i +
Ru(4,7-dtolphen):+
Ru(5,6-dmphen): +
pheMpyr)W
Ru(4,7-C12phen): +
Ru(4,7-Ph2-
Ru(4,7-dmphen)i +
Ru(4,7-dm-
phN:+
Ru(4,7-dm-
SCE(H,O)
SSCE
NHE
SCE
SCE(H,O)
AN
1230
1190
1090
NHE
Ag/AgNO,
1220
1230
1370
770
810
1070
1090
1120
1260
1230
1290
1490
990
1360
1360
1400
1390
310
NHE
AN
Hz0
Ag/AgNO,
SCE
SCE(H20)
AN
AN
SCE
SSCE
SCE
NHE
NHE
NHE
SCE
AgRE
SSCE
SCE
Ag/AgCl
SCQH,O)
SCE(H,O)
SCE(H,O)
SCE(HzO)
SCE
NHE
SCE
SCE
SCE
SSCE
SCE(H,O)
Ag/AgCl
SCE
SCE
SCE
NHE
NHE
NHE
SCE
SCE
SCE(H,O)
SCE(H,O)
AN
AN
AN
H2O
H2O
ph@:+
Hz0
phe@:+
Ru(4,7-dm-
AN
phW:+
Ru(4,7-dmCH,CI,
AN
H,O
AN
AN
(pyrNCU+
Ru(S-m-phen)$+
Ru(S-m-phen)g+
Ru(S-Ph-phen):’
Ru(4,7_dm-
phW:+
Ru(4,7-dmphen): +
Ru(4,7-dm-
H,O
AN
AN
CH,Cl,
H,O
H,O
AN
H,O
AN
AN
Ru(phen)(Htxl)
Ru(S-Cl-phen):+
Ru(S-Cl-phen)$+
Ru(S-Cl-phen)!+
Ru(5-Cl-phen):’
Ru(S-Cl-phen):+
Ru(S-Br-phen):’
Ru(S-Br-phen):+
Ru(S-n-phen)G+
Ru(S-n-phen),
E,
_
_
_
= irr.
149
149
12
149
169
- 1470
-1160
- 1280
2080
149
- 930
12
47
670
224
149
395
430
3%
393
-990
-1010
-960
-900
- 1010
12
176
670
670
890
lo00
- 1470
-1010
- 1010
-900
-900
- 870
- 760
-760
- 670
-770
481
169
149
447
12
176
149
393
149
430
447
2120
2130
2130
2150
- 770
loo0
- - 1210
- 1520
-1310
- 850
-1150
-1150
-600
-1220
b
w
99
loo
100
100
100
101
103
104
108
109
109
110
181
181
123
123
123
123
125
99
100
100
100
100
101
103
104
108
109
109
110
111
118
123
123
123
123
125
*
99
99
125
123
123
123
123
181
110
181
109
109
108
101
103
104
100
loo
100
138
99
99
99
281
281
281
281
276
H,O
H,O
Cl
H2O
phe&+
Ru(5,6-dm-
99
99
(trpYj2+
@PYj2’
RuWvpy),
@PY)2+
Ru(t-stylb),
WQVPY)~
(wY)2+
W4-VPY),
(HCPZ~)~+
W4-TY),
AN
AN
AN
AN
AN
AN
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
1200
1210
1230
1230
1170
1880
1400
1880
- 1250
- 1240
-1240
- 1580
- 280
-130
-320
-700
-700
1600
1600
NHE
NHE
SSCE
SCE
- 710i
1580
NHE
-1340
-1340
- 1288
-760
-840
E,
1120
1930
1800
SSCE
SSCE
SSCE
SSCE
SCE
03~0)~
tH&‘)‘+
tc-Ru(pWAzpy)2
WN’JO, *
WAgNO,
WWO,
SSCE
SCE
AN
AN
AN
AN
AN
AN
730
1050
790
1200
1200
1266
E,,
SCE
SCE
SCE
SSCE
AN
SCE(H,D)
SCE
SCE
SSCE
SCE(H,D)
Ag/AgCl
AN
CHJI,
H20
SCE
NHE
SCE
SCE
NHE
AN
Ru(phen-dione):+ AN
AN
tc-Ru(pyWpyIz
Ru(taphen):+
Ru(taphen):+
ww)
+
Ru(tnGphen):+
Ru(TAP): +
Ru(2,7-dmTAP);+
Ru(DIAFO):+
phe@:+
Ru(5,6-dmphen): +
Ru(tml-phen):+
Ru(tml-phen):+
Ru(tml-phen):+
Ru(ttnl-phen),
Hz0
phe&+
Ru(S&dmNHE
SSCE
SSCE
DMF
Ru(5,6-dm-
99
99
99
Stand.
Ref.
Solvent
Complex
Ligands
(a) Mononuclearcomplexes
TABLE 3 (continued)
1990
2140
2130
Eo-0
-390
-1040
c -210
< -360
-1110
-1110
- 930
*E
OX
1290
~1380
~1320
860
lkd
E,, surf.
pit = 3-picoline
* R@PY):+/
t 1260 mV
+ 1260 mV
* Ru(bpy): +/
-
-
Notes
-. ...- ...^.._II
._...
448
478
478
448
448
435
435
480
238
40
40
149
397
393
149
447
393
430
3%
176
12
69
Ref.
125
127
143
160
160
160
161
161
163
en
176
180
180
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
125
127
143
160
160
160
161
161
163
168
176
180
180
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
181
en
en
tu
181
181
181
181
181
182
180
I
I
Br
Br
Br
CN
CN
Cl
Cl
Cl
Cl
Cl
Cl
N,
OH
176
AN
en
143
160
160
160
161
161
163
127
281
tu
I
I
Br
Br
Br
CN
CN
Cl
Cl
Cl
Cl
Cl
Cl
N,
OH
AN
281
281
281
281
281
281
Cl
AN
AN
AN
AN
AN
AN
AN
(trpY)2+
Ru(2,7-dmnapy)i+
Ru(BPE),(trpy)2+
Ru(BPE),(trpy)‘+
Ru(BPE),(trpy)‘+
Ru(PC2),(trpy)2+
Ru(PC2),(trpy)**
Ru(DPAH); +
(32’32
H2O
CH2C12
RuWPY)~(CN),
WpuP~)2092
CH2’32
CH,Cl,
W~PYMW,
tc-Ru(~py),
W~pyJ2+
Ru(Awy):+
Ru(Azpy): +
R~(~PY): +
Ru(~PY)~
AN
Hz0
CH2C12
AN
AN
WAZPY):+
R~(~PY):+
AN
AN
H20
W~py)2WZ+
W~py)2W:+
AN
WAzpy)2@n~2+
+
SWH20)
Mbpy) : +
Wbpy):
SWH20)
Wm’):+
Wbpy):+
SCE
AN
Ru(~PYI,(C~),
W-02
Ww): +
CH,CI,
CH2’32
Y-W~PYI~W),
CH,CI2
a-Ru(h~~),(C1)2
B-W~PY),(CO,
AN
CH2C12
W~PYJ,(CU~
RuWPYIZ(C~)Z
SCE
SCE
SCE
SCE
SCE
Ru(W):
+
Ru(bpy): +
AN
CH,Cl 2
RuWpyh(Brh
Ru(Azpyh(Brh
R~(~PY),(B~)~
R~(~py),(I),
AN
CH2C12
SCE
Ru(Azpy)z(I)z
AN
AN
H2S04
AN
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SCE
SCE
SCE
SCE
SCE
Ru(pydipy):+
(AN):+
WPY~PY),
Ru(biimH2):+
4M
AN
(trpyXCl)+
Ru(4’-Chtylb),
Ru(diim)(en)i+
AN
Ru(t-stylb),
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
NHE
SCE
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
Fc+/O
SSCE
SSCE
2140
1140
21Ocl
925
965
1210
1150
1000
1110
960
1070
1170
853
910
950
985
1190
440
1360
740
1370
1230
1260
1240
1320
1320
530
1200
770
- 310
-70
- 320
-130
60
-90
- 116
300
- 110
- 520
- 580
-540
-240
- 480
- 2600
- 1220
-1240
-1260
- 1220
- 1250
-1380
= E/PVC
mer
mer
Deuterated
AN
E,
E,, surf.
-40°C,
E,, surf.
Ed = E/iv
375
376
375
432
375
375
399
376
432
435
369
452
452
452
452
375
376
375
452
452
500
500
500
399
375
507
369
4%
517
448
478
478
478
478
235
448
448
i
H,O
H,O
aca
aca
182
I
Cl
182
Hz0
H,O
1x5
187
188
Br
Br
Cl
Cl
Br
181
181
181
181
181
182
182
182
182
182
182
182
183
183
184
185
187
188
190
190
190
190
192
181
181
181
181
181
181
182
182
182
182
182
182
183
183
184
185
187
188
189
189
189
189
191
Cl
183
184
Br
NO2
186
181
181
Br
Br
Cl
Cl
Br
Cl
H2O
H2O
Cl
Br
I
NO2
Hz0
OH
RU@PY) 2
(B~.z)~+
186
181
181
2
Ru(Ll)(HLl)(Br),
Ru(Ll)(HLl)(Br),
Ru(Ll)(HLl)(Cl),
Ru(Ll)(HLl)(Cl),
Ru(U)(HL2)(Br),
Ru@mth): l
Ru(bt); +
Ru(PTPI) : +
R@PY):+
Ru(NA);+
Ru(W,Kl),
CH2C12
AN
AN
CH,Cl,
AN
AN
AN
1M
HNO,
AN
AN
AN
AN
W,O):+
(H,O):+
cc-Ru( MeAzpy) z
AN
AN
AN
2
AN
Ru( MeAzpy) 3+
tc-Ru(MeAzpy) 2
(a,
RU(M~PY)
UW2
Ru(Mkey)
(02
AN
SCE
SCE
SCE
SCE
SCE
NHE
NHE
SCE
Ag/AgNO,
Ag/AgNO,
SCE
SCE
SCE
SCE
SCE
SCE
NHE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE(H,O)
SCE
SCE
SCE
SCE
SWH,O)
H2O
AN
R~(~PY)
(Mehpy)?
Ru(Mehpy),
Ru(bpy):+
CH,Cl,
Ru(bpy);+
WWy)2@4*
CH,Cl,
420
330
390
310
520
1310
1248
1170
1280
1270
2230
907
897
907
1540
1780
2190
SCE
AN
WE
1180
SCE
1800
AN
SCE
SCE
I%,,~
2ooo
Ru@p
y): +
AN
Stand.
H2O
Ref.
Solvent
RWw)2Wdt
(NW2
Ru(Gzp~) 2
(H20)22+
tc-RuWpyh
W,OXOH) +
tc-Ru(Azpy) 2
R~(~PY),
(B~z)~+
Complex
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
- 730
E,
= E/p,c
E,, = E/p,c
= E/w
E,, from polarogramm
mer
mer
Notes
- 830
- 730
OX
lE red
E,
2010
*E
- 850
- 1215
- 954
15
- 370
-100
-360
- 730
- 720
- 730
-380
-140
-80
-460
-360
-580
-190
-430
E,
@O
499
499
499
499
499
514
514
360
399
399
370
435
432
435
452
452
452
375
376
432
375
435
435
376
375
Ref.
%
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
197
198
198
198
198
199
199
199
199
200
201
202
202
202
243
263
245
197
198
198
198
198
199
199
199
199
200
201
202
202
202
243
243
245
245
Cl
Cl
Br
Cl
Cl
Br
Br
Cl
Cl
Br
Br
Cl
Cl
Cl
192
192
192
194
194
194
194
196
1%
1%
1%
197
191
191
191
193
193
193
193
195
195
195
195
197
AN
CH,Cl,
(Cl),
cis-Ru( mdm) z
(Cl),
rrons-Ru(mmd)z
Cl
Cl
Cl
Cl
Cl
Cl
Cl
(Cl) 2
cis-Ru(htt)2(CI)2
cis-Rw(btt)z(Cl),
Ru(4’-MeL),
Ru( 4’-MeL)
(GLH)
Ru(B-bpy-H2);+
rruns-Ru(htt)2
(CO,
rruns-Ru(hmd) 2
AN
CH,Cl,
AN
DMF
DMF
CHzCll
CH,Cl,
CHzCll
(Cl),
cis-Ru( mdm) 2
m2
AN
(Cl),
rrans-Ru( mdm) 2
Cl
CH,Cl,
AN
CH,Cl,
w2
rruns-Ru(mtt)z
AN
CH,Cl,
Ku2
cis-Ru(mtt),(Cl),
cis-Ru(mtt)2(C1),
rranr-Ru(mdm) z
Cl
Cl
Cl
Cl
Cl
CH,Cl,
(Cl),
rrans-Ru(mtt) 2
CH,Cll
AN
CH2Clz
AN
CH,CI,
AN
CH,Cl,
AN
CH,Cl,
AN
CH,Cl,
CH,Cl,
cis-Ru(mpp)2
(Cl),
Ru(IA)(HLA)(Cl),
Ru(LA)(HU)(Cl),
krmr-Ru(mpp) 2
Cl
Cl
Cl
Cl
Ru(WW~XW2
Ru(L2)(HL2)(Br),
Ru(L2)(HLZ)(Cl),
Ru(LZ)(HLZ)(Cl),
Ru(L3)(HL3)(Br),
Ru(L3)(HL3)(Br),
Ru(L3)(HL3)(Cl),
Ru(L3)(HL3)(Cl),
Ru(L+o(LA)(Br),
Br
Cl
Cl
Br
Br
Cl
Cl
Bf
Br
s ref
s ref
s ref
s ret
s ref
s ref
s ref
s ref
s ref
s ref
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
s ref
NO, *
WAg
WAgNO,
NHE
s ref
s ref
NHE
NHE
s ref
kit/ AgNO, s ref
WAgNO
&/&W
&/&NO3
W&W4
WAgNO,
W&NO,
Ag/W%
Ag/kzWh
WhW,
Ag/AgNt&
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
SCE
1230
410
330
278
324
200
190
-60
100
160
-190
130
90
-150
-190
-100
220
420
480
410
470
380
450
360
460
400
440
370
-60
-460
620
Ed = E/w
-850
1690
E, = E/w
-810
-1070
- 1200
- 1280
- 1381
-1110
- 1290
- 1690
- 1750
- 1880
- 1650
- 1810
- 1710
- 1770
-1640
- 1710
- 1750
- 1670
+ 1260 mV
* Ww):+/
_
E,, = E/P,c
E, = E/P ,c
- 880
-830
Emi = E/P,c
- 780
40
505
505
498
498
505
505
505
505
505
505
505
505
505
505
505
505
499
499
499
499
499
499
499
499
499
499
499
so5
AN
AN
DMF
DMF
AN
DMF
DMF
AN
Ru(pynapy)?
Ru(DHCH);+
Ru(DMCH),
(CW,
Ru(DMCH) 2
(CN),
Ru(DMCH),
KN),
Ru(DMCH),
(CN),
Ru(DMCH),
(Cl) 2
Ru(DMCH);+
Ru(DMCH)$+
241
251
250
251
251
251
251
257
257
257
CN
CN
CN
256
256
252
252
257
252
251
251
257
Ru(dinapy)$+
Ru(dinapy@
251
251
251
256
251
251
251
256
Cl
251
251
256
CN
251
251
256
CN
251
251
CN
CN
CN
Cl
CN
DMF
AN
(CN),
Ru(biq) 2
(CN),
Ru(biq),
(CNI 2
DMF
AN
AN
AN
AN
AN
Ru(biq),
Ru(DPCH);+
Ru(DMCH);+
CN
CN
251
CN
CN
CN
250
241
247
250
DMF
Ru(ti:+
246
246
AN
RuO:+
246
246
Solvent
246
Complex
246
Ligands
(a) Mononuclear complexes
TABLE 3 (continued)
AtW,
*
NO3
Ad-%
NO3
Ais/&
NO3
Ag/ Ag
NO,
Ag/Ag
SSCE
NO3
&/At3
NO3
At%/&
NO3
.%/&
NO3
AU&
W
NO3
W&
NO3
A%/-%
NO3
Ais/&
NO3
AdAi!
NO3
Ag/Ag
SSCE
SSCE
Ref.
NHE
SSCE
NHE
NHE
NHE
NHE
*
*
*
*
900
940
940
980
970
1420
1260
1260
1260
460
890
770
830
830
* Ru(bpyI:+/
+ 1260 mV
+ 1260 mV
* Wbpy):+/
at -54OC
Notes
-1040
- 980
- 980
-840
- 830
-900
-900
-900
- 895
- 1010
1680
1480
1690
1690
-740
- 650
- 510
- 430
- 430
700
610
650
790
790
+/
514
402
239
40
329
239
40
221
221
40
221
239
402
473
473
Ref.
221
40
.__-._
_-_- ..I..”-.
* Ru(bpy): +/
1260 mV
* Ru(bpy):* /
+ 1260 mV
+ 1260 mV
* Ru(bpy):+/ 221
+ 1260 mV
* WW:
* Ru(bpy):+/
+ 1260 rnv
* Ru(bpy):+/
+ 1260 mV
420
560
480
700
*-K,
- 1120
- 970
- 860
- 780
-610
*En,
* Ru(bpy):+/
+126OmV
1430
1690
1690
Eo-0
- 1230
-1130
-1130
-755
1425
*
-990
1080
NHE
- 1058
SSCE
-1460
&,,
Fc+/O
1333
E,,
SSCE
Stand.
_ ”
257
257
251
251
259
259
259
259
259
259
261
261
266
261
267
281
281
281
281
NH,
286
286
257
257
257
257
259
259
259
259
259
259
261
261
266
267
267
281
281
281
281
281
286
286
NH,
267
267
266
261
261
259
259
Cl
CN
CN
257
CN
257
Cl
CN
NH,
Cl
CN
CN
CN
Cl
CN
DMF
(CN),
Ru(bih
AN
DMF
DMF
Ru(biq$+
Ru(i-b&
(CN),
Ru(i-biq),
AN
AN
AN
AN
(Cl),
Ru(i-biq):’
Ru(i-biq):’
Ru(DP);+
Ru(DP);+
H2O
Ru(TPTZ);+
AN
AN
H2O
AN
Wtrpy):+
RuWy)
2+
(NH,),
Ru(TPTZ): +
Wrpy):+
Ru(dpp);+
Ru(dpp): +
Wrpy):+
R@w~:+
AN and
DMF
AN
AN
DMF
AN
DMF
(CN) 2
Ru(i-biq),
Ru(Mebpy3DQt2g+
DMF
Ru(i-biq),
092
AN
Ru(biq):+
KU,
DMF
Ru(biq) 2
SCE
SCE
NHE
NHE
SCE
NHE
SCE
AS/Ag
NO3 *
SCE
SCE
SSCE
SCE
SCE
SCE
SCE
SCE
SSCE
SCE
SCE
*
NHE
NHE
*
*
*
l
NHE
l
l
ABRE
SCE
NO3 *
As/As
NO3
&c/k
NO3
W&t
NO3
Ag/Ag
NO3
WAg
NO3
b/k
NO3 *
AU&
NO3
WAg
NO3
AU&
1490
1520
1250
740
1260
1680
1680
1264
1280
1150
1370
1385
1120
1120
380
740
730
1470
730
1470
610
1010
- 770
-840
- 1360
- 1530
-1290
- 950
-950
- 1266
- 1430
- 1370
-1000
-916
- 15lOi
- 1510
-1460
-1640i
-1500
- 730
- 164Oi
- 730
-900
- 970
2080
2300
1700
2290
1730
1730
1450
1130
790
-810
-800
240
800
830
510
830
550
-400
-1180
- 1320
- 1560
- 260
- 1420
-260
-840
Rutbpy):+/
+ 1260 mV
Ru(bpy):+/
t 1260 mV
Peak potentials
l
Peakpotentials
* Ru(bpy):+/
+ 1260 mV
E = AN,
EL = DMF
E/PJ
* Wm):+/
+ 1260 mV
* Ru(b~y)f+/
t 1260 mV
E, = irr.,
l
* Ru(bpy): +/
t 1260 mV
* Ru(bpy):+/
t 1260 mV
* Ru(bpy);+/
+ 1260 mV
* Ru(bpy):+/
t 1260 mV
1260 mV
* Ww): +/
.._.^..“.l.._..”
12
4
12
501
40
403
403
69
4
444
395
513
40
131
40
221
40
344
221
40
40
221
.
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ligands
61
61
61
61
62
1
1
1
1
1
1
1
1
1
1
1
1
1
1
61
Cl
61
1
1
61
Cl
1
51
1
1
(I),
I
1
1
1
1
Cl
1
1
1
1
51
1
1
1
(b) Polynucleat complexes
TA3LE 3 (continued)
Cl
Cl
Cl
210
210
102
2
2
2
2
2
2
2
2
2
(bpy),Ru4+
(4,4’-dm-bpym)
(C1XWWCl)
@wW2+
W’w y)z
Ww)
~~~~X’-w)
Wwy)
;yX’w)
Ww)
t$Nw)2
Ru(bw)
f$+mXbwJ
Ww92
;vN@w)
RMw)
($Mbp y) 2
(Ru(bpy)z)o
(BL3)s+
Ru(bpy)z
(ClM4,4’-bpy)
(ClMbpy)zRu*+
Ru(bpy) z
(Cl)(rtP’-bpy)(Cl)
(bpy),0s2+
Ru(bpy)z
(Ru(bpy),),
(BL3)6+
(NOphen)b+
tWwM,
Complex
AN
AN
AN
AN
AN
AN
AN
SSCE
SCE
SSCE
SSCE
SCE
SSCE
SCE
SSCE
Ru(bpy):
+ NHE
SSCE
SCE
SSCE
SSCE
NHE
Ag/AgNO,
AN
SSCE
SSCE
SSCE
AN
1600
990
1740
1690
1620
1760
1770
1705
830
850
1640
SSCE
SSCE
SSCE
AN
1630
1480
EonI
SSCE
AN
SSCE
&‘&Cl
WA&l
Acetone
AN
Standard
Reference
Solvent
1430
870
1550
1530
1440
1180
1610
1520
410
800
1460
1460
Eox2
-410
-425
-
-220
plot
E,, from peak
max (Ai/AE)
Differential pulse
polarography,
Eox, = irr.
Differential pulse
potarography,
I&, = irr.
I$, from peak
max (Ai/AE)
plot
-
-
Differential pulse
polarography
Differential pulse
polarography
-
-
Notes
-310
-1110
Ed
_-, ___Ix_-
360
490
361
454
360
440
440
511
440
440
372
372
451
Ref.
._.” _
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
I39
139
1
1
1
1
1
1
1
1
1
1
1
269
1
1
1
268
1
1
270
267
1
1
177
1
1
144
138
138
138
1
1
Cl
1
1
144
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
Cl
z
AN
AN
W’wyh
fuul;3tXbiv) 2
z
AN
AN
AN
AN
AN
AN
AN
AN
AN
CHzClz
W’w),
f$Mbyh
tj$;Xby)
Wbpy),
(bpy),Ru*+
WbPy),
$‘““”
z
Ru(bpy)t
(BiBzim)
W;(b py)z
(Cbo(yw1)
(bPy)zRu’+
Wbpy),
(C1XPW)
(bPy)@+
Wbpy) 2
(C1XPyzc)
(bPy),Os*+
Wbpy),
WW,
(bpyWs’+
KWYrXC1)
Wbpy),
(bpy)zRu*+
WwW
Ww)
Ww) 2
K&@wh
SSCE
SSCE
SSCE
AfVA@
SCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
SSCE
1620
SSCE
SSCE
SSCE
1756
1420
1450
1470
1566
740
830
1210
1040
620
930
890
510
890
910
1060
1140
1010
NHE
SCE
SSCE
SSCE
SSCE
SSCE
1010
1020
SSCE
SSCE
1460
SSCE
-670
-160
-370
-
-
-
E,, = ( Wp,a
+ E/P,@
440
Differential pulse
polarography
372
454
454
103
485
367
440
466
440
440
Differential pulse
polarography
Differential pulse
polarography
Differential pulse
polarography
457
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Ligands
1
1
138
138
Cl
114
138
68
68
111
257
Cl
57
1
61
57
57
1
1
1
1
1
1
1
NH,
Cl
Cl
177
257
NH,
(NH&
280
279
278
277
275
(b) Polynuclear complexes
TABLE 3 (continued)
NH,
NH,
NH,
NH,
(NH,),
(NH,),
(NH,),
(NH,),
Ru(bpy),
(CMpyrXpy)
(NH&Ru3+
Ru(bpy)z
(cl)(PYr)(3;c+-PY)
@JH,),Ru
Ru(bpyI2
K$wXNH,),
Ru(bpy),
(BiBzim)(phen)2
Ru2+
%@(biq)2
(NH&;+
Ru(bpy)2
(W4,4’-b;;)
WW,Ru
Ru(bpy) 2
(bpy)2Ru4+
(Ru(bpy) 2
(W4,4’-bpy)
Ru(bpy),
(3amdiphen)
(Zamdiphen)(bpy) 2
Ru’+
Ru(bp
y)2
W$he@o(P
y12
R+PY),
Ru(‘wh
~~+htWC-w9
2
W$Kbwh
Wwh
Complex
AN
AN
AN
AN
AN
AN
AN
Acetone
Acetone
Acetone
W&Cl
SCE
SCE
SCE
SCE
Ag/AgNO,
SSCE
SSCE
WAgCl
W&Cl
SCE
SCE
SCE
SCE
NHE
SSCE
SSCE
Ats/AgC~ Ag/AgCl
Ag/AgCl
NHE
WAgNO,
AN
Acetone
Standard
Reference
Solvent
965
1005
1012
545
770
735
730
1620
1765
1020
430
430
1415
EoX2
830
1370
1520
1460
1440
1470
141s
E_.,
-275
-960
-1000
-1100
-1090
-240
Erai
-
-
-
-
-
-
Notes
508
508
508
485
511
510
459
451
451
451
451
511
Ref.
$
159
159
160
160
CN
CN
1
1
1
1
1
1
1
1
1
1
(NH,),
1
1
1
1
1
1
1
1
1
1
61
CN
CN
CN
CN
138
1
1
138
1
1
CN
CN
CN
CN
CN
CN
160
Cl
159
Cl
138
Cl
W3ho
(NH,),,
WH3ho
(NH,),,
(NH,),
W-V,
NH3
NH3
(NH,)10
NH,
NH3
(NH,),
(NH313
3+
3+
WH3)4Ru
Wym)
ROJW,
(WM:+
RQpy),
(CN),(Ru
(NH,),):+
Ru(bpy) 2
(CN),tRu
(NH,)&+
R0py) 2
(CN),(Ru
(NH,),):+
Ru(bpy),
(CN),(Ru
Ru(NH,),
CN(bpy) z
RuCN*+
(NHd’
Ru(NH,),
CNfbpy) 2
RuCN’+
(R@PY)z
(Ru(BPE)
4+
(NHd&+
Rdbpy),
(Cl)(BPE)
(NH3),Ru3+
(NHhRu
(Rutbpy) 2
(Ru(BPA)
(Cl)(BPA)
RWW,
(~H3)5)62+
(RU(PYI)
VWb92
W3W
NH, (NH,), Wbmh
C%wr)
H2O
H2O
H@
DMF
DMF
H2O
DMF
AN
AN
AN
AN
AN
AN
SCE
SCE
SCE
SCE
SCE
SCE
SSCE
SCE
SSCE
SSCE
SSCE
SCE
NHE
SCE
SCE
SCE
SCE
SCE
SCE
SSCE
SCE
SSCE
SSCE
SSCE
SCE
1020
1170
-55
1240
-90
-100
1140
1320
810
1270
790
1790
1030
830
-55
-125
-90
-174
-170
400
410
360
370
700
610
-174
-1520
-
-
460
518
518
518
518
518
518
459
510
459
510
459
510
244
F. APPENDIX
(i) Abbreviations for Iigands
Numbered Ligands
N
119
113
116
154
279
4-a-bpy
4-acetyl-py
2-AEP
3-AEP
All-trz
2amdiphen
280
3amdiphen
82
181
22
52
89
105
5-a-phen
AZPY
4,4’-BAA-bpy
5,5 -BAA-bpy
‘
4,7-bbr-phen
BDCMP
106
BDCMPHZ
177
178
179
174
175
176
257
268
269
270
271
272
273
BiBzim
BiBzimH
BiBzimH 2
Biim
BiimH
biimH,
biq
BLl
BL2
BL3
BL4
BL5
BL6
274
90
8
159
BL7
4,7-bmo-phen
4-bo-bpy
BPA
4
4-amino-2,2’-bipyridine
4-acetyl-pyridine
2-(2-aminoethyl)pyridine
3-(2aminoethyl)pyridine
4-allyl-1,2,4-triazole
3-oxopentamethylenebis(l,lO-phenanthroline-2carboxamide)
3,6-dioxooctamethylenebis(l,lO-phenanthroline2-carboxarnide)
5-amino-l,lO-phenanthroline
2-(phenylazo)pyridine
4,4’-bis(acetoamido)-2,2’-bipyridine
5,5 -bisacetoamido-2,2’
‘
-bipyridine
4,7-bis-( p-bromophenyl)-l,lO-phenanthroline
4,7-bis(dicyanomethylydene)-1,4,7,10-tetrahydrol,lO-phenanthroline
4,7-bis(dicyanomethylydene)-1,4,7,10-tetrahydro1 ,lO-phenanthroline
2,2’-dibenzimidazolate
dianion
2,2’-dibenzimidazolate
anion
2,2’-dibenzimidazole
2,2’-biimidazolate
dianion
2,2’-biimidazolate
anion
2,2’-biimidazole
2,2’-biquinoline
2,3-di-2-pyridylquinoxaline
2,3,7,8-tetra-2-pyridylpyrazino[2,3-glquinoxahne
2,2’,3,3’-tetra-2-pyridyl-6,6’-biquinoxaline
1,2-bis[4-(4’-methyl-2,2’-bipyridyl)]ethane
1,5-bis[4-(4’-methyl-2,2’-bipyridyl)]pentane
1,4-bis[4-( a-ethyl)-4’-methyl-2,2’-bipyridyllbenzene
1,12-bis[4-(4’-methyl-2,2’-bipyridyl)]dodecane
4,7-b&( p-methoxyphenyl)-l,lO-phenanthroline
4-benzyl-oxy-2,2’-bipyridine
1,2-bis-(4-pyridyl)-ethane
245
95
4,7-bpbr-phen
160
91
76
96
BPE
4,7-bph,-phen
4-bph-phen
4,7-bpmo-phen
97
64
1
57
49
61
59
60
3
98
4,7-bpph-phen
bprid
bPYm
bPZ
bpzH
4-Br-bpy
4,7-brmo-phen
80
77
187
186
35
5-Br-phen
4-BrPh-phen
bt
Btz
C12B
36
C16B
bPY
4,4’-bpy
bpyCOOH
87
2
72
79
114
127
45
129
19
25
17
27
44
4,7-Cl ,-phen
4-Cl-bpy
4-Cl-phen
5-Cl-phen
3-Cl-py
4’-Cl-stylb
4,4’-cm-bpy
4’-CN-stylb
4,4’-da-bpy
4,4’-DBO-bpy
4,4’-dBr-bpy
4,4’-dbz-bpy
4,4’-DCA-bpy
40
29
4,4’-DCB-bpy
4.4’-dc-btw
4-p-biphenylyl-7-p-bromophenyl-l,lOphenanthroline
trans-1,2-bis-(4-pyridyl)-ethylene
4,7-bis-(biphenylyl)-l,lO-phenanthroline
4-p-biphenylyl-l,lO-phenanthroline
4-p-biphenylyl-7-p-methoxyphenyl-l,lOphenanthroline
4-p-biphenylyl-7-phenyl-l,lO-phenanthroline
3,3’-bipyridazine
2,2’-bipyridine
4,4’-bipyridine
polymeric bpy ligand (see figure)
2,2’-bipyrimidine
2,2’-bipyrazine
protonated bpz
4-bromo-2,2’-bipyridine
4-p-bromophenyl-7-p-methoxyphenyl-1
,lOphenanthroline
5-bromo-l,lO-phenanthroline
4-p-bromophenyl-l,lO-phenanthroline
2,2’-bi-2-thiazoline
4,4’-bithiazole
N, N ‘-di(dodecyl)-2,2’-bipyridine-4,4’-dicarboxyamide
N, N ‘-di(hexadecyl)-2,2’-bipyridine-4,4’-dicarboxyamide
4,7-dichloro-l,lO-phenanthroline
4-chloro-2,2’-bipyridine
4-chloro-1 ,lO-phenanthroline
5-chloro-1 ,lO-phenanthroline
3-chloro-pyridine
4’-Cl-trans-4-stilbazole
4-carboxy-4’-methyl-2,2’-bipyridine
4’-cyano-trans-4-stilbazole
4,4’-diamino-2,2’-bipyridine
4,4’-dibenzyloxy-2,2’-bipyridine
4,4’-dibromo-2,2’-bipyridine
4,4’-dibenzyl-2,2’-bipyridine
N, N ‘-di(ethyl)-2,2’-bipyridine-4,4’-dicarboxamide
4,4’-dicarboxybenzyl-2,2’-bipyridine
4,4’-dicarboxy-2,2’-bipyridine
246
34
37
51
14
38
53
16
34
41
42
21
23
43
250
94
107
108
275
168
256
4,4’-DCC-bpy
4,4’-DCE-bpy
5,5 ‘-DCE-bpy
3,3’-DCI-bpy
4,4’-DCI-bpy
5,5 ‘-DCI-bpy
4,4’-dCl-dpy
4,4’-DCM-bpy
4,4’-DCNE-bpy
4,4’-DCNY-bpy
4,4’-DEA-bpy
4,4’-DEO-bpy
4,4’-DHC-bpy
DHCH
4,7-dhy-phen
DIAF
DIAFO
difln
diim
dinapy
277
2diphen
278
4diphen
5
258
13
15
50
54
62
63
251
4-dma-bpy
dm-biq
3,3’-dm-bpy
4,4’-dm-bpy
5,5 ‘-dm-bpy
6,6 ‘-dm-bpy
4,4’-dm-bpym
6,6 ‘-dm-bpym
DMCH
143
85
86
99
104
18
31
2,7-dm-napy
2,9-dm-phen
4,7-dm-phen
5,6-dm-phen
2,7-dm-TAP
4,4’-dn-bpy
4,4’-dnd-bpy
4,4’-dicarboxycyclohexyl-2,2’-bipyridine
4,4’-dicarboxyethyl-2,2’-bipyridine
5,5’-dicarboxyethyl-2,2’-bipyridine
3,3’-dicarboxyisopropyl-2,2’-bipyridine
4,4’-dicarboxyisopropyl-2,2’-bipyridine
5,5’-dicarboxyisopropyl-2,2’-bipyridine
4,4’-dichloro-2,2’-bipyridine
4,4’-dicarboxymethyl-2,2’-bipyridine
4,4’-dicarboxynaphth-2-yl-2,2’-bipyridine
4,4’-dicarboxynaphthan-l-yl-2,2’-bipyridine
4,4’-bis(diethylamino)-2,2’-bipyridine
4,4’-diethoxy-2,2’-bipyridine
4,4’-dicarboxydihydrocholesteryl-2,2’-bipyridine
See figure
4,7-dihydroxy-l,lO-phenanthroline
4,5diazafluorene
4,5-diazafluoren-9-one
see figure
glyoxal-diimine
5,6-dihydro-dipyrido[3,2-b
: 2’,3’j][l,lO]phenanthroline
2,2’-(3-oxopentamethylenedioxy)bis(l,lO-phenanthroline)
2,2’-(3,6,9-trioxoundecamethylenedioxy)bis(l,lOphenanthroline)
4-dimethylamino-2,2’-bipyridine
4,4’-dimethyl-2,2’-biquinoline
3,3’-dimethyl-2,2’-bipyridine
4,4’-dimethyl-2,2’-bipyridine
5,5 ‘-dimethyl-2,2’-bipyridine
6,6’-dimethyl-2,2’-bipyridine
4,4’-dimethyl-2,2’-bipyrimidine
6,6’-dimethyl-4,4’-bipyrimidine
5,6-dihydro-4,7-dimethyldibenzo[3,2-b
: 2’,3’-j]
[l,lO]phenanthroline
2,7-dimethyl-1,8-naphthyridine
2,9-dimethyl-1, lo-phenanthroline
4,7-dimethyl-1, lo-phenanthroline
5,6-dimethyl-l,lO-phenanthroline
2,7-dimethyl-1,4,5,8_tetraazaphenanthrene
4,4’-dinitro-2,2’-bipyridine
4,4’-dinonadecyl-2,2’-bipyridine
247
261
162
163
252
158
26
157
24
267
285
284
20
42
32
28
30
93
229
231
233
235
237
239
241
242
208
209
207
206
210
260
56
276
230
232
234
236
238
240
219
218
217
DP
DPA
DPAH
DPCH
DPE
4,4’-dph-bpy
DPM
4,4’-DPO-bpy
dPP
dpt
dqp
4,4’-ds-bpy
4,7-dsph-phen
4,4’-dst-bpy
4,4’-dsty-bpy
4,4’-DTB-bpy
4,7-dtol-phen
el
e2
e3
e4
e5
e6
e7
e8
EtTrOCl
EtTROCOOEt
EtTROH
EtTROMe
EtTRON02
H2por
H4bpy
HCpz3
He1
He2
He3
He4
He5
He6
HHyamCl
HHyamH
HHyamMe
dipyrido[3,2-a : 2’,3’-clphenazine
di-2-pyridylamine anion
di-2-pyridylamine
See figure
di-( 2-pyridyl)-ethane
4,4’-diphenyl-2,2’-bipyridine
di-(2-pyridyl)-methane
4,4’-diphenoxy-2,2’-bipyridine
2,3-bis(2-pyridyl)-pyrazine
6,6’-diphenyl-2,2’,2”-terpyridine
2,6-di-(2’-quinolyl)pyridine
4,4’-disulphonate-2,2’-bipyridine
disulfonated 4,7-diphenyl-IJO-phenanthroline
4,4’-distearyl-2,2’-bipyridine
4,4’-distyryl-2,2’-bipyridine
4,4’-di-tert-butyl-2,2’-bipyridine
4,7-ditolyl-l,lO-phenanthroline
hydroxyimatoacetophenone
hydrox-atopropiophenone
cr-benzil-oximato
biacetyl-oximato
hydroxyimatopropyl-methyl-ketone
a-hydroxyimato-ar-phenylacetone
hydroxyimatomalonamide
alloxane-5-oximato
I-ethyl-3-p-chlorphenyltriazene-l-oxidato
l-ethyl-3-p-carboxyethylphenyltriazene-l-oxidato
l-ethyl-3-phenyltriazene-l-oxidato
l-ethyl-3-p-tolyltriazene-1-oxidato
l-ethyl-3-p-nitrophenyltriazene-I-oxidato
See figure
3,4,5,6-tetrahydro-2,2’-bipyridine
tris-(pyrazolyl)-methane
hydroxyiminoacetophenone
hydroxyiminopropiophenone
cx-benzil-oxime
biacetyl-oxime
hydroxyiminopropyl-methyl-ketone
a-hydroxyimino-a-phenylacetone
p-chlorphenylhydroxamato
phenylhydroxamato
p-tolylhydroxamato
248
220
216
190
192
194
196
201
67
245
155
202
227
228
226
259
146
167
120
121
164
115
189
191
193
195
263
HHyamN02
HHyamOMe
HLl
HL2
HL3
HL4
hmd
h-phen
58
10
131
199
m-4,4’-bpy
6-m-bpy
m-cinn
mdm
182
265
266
264
224
223
222
225
221
243
MeAzpy
Me-bpy-2DQ
+ 2
Me-bpy-3DQ
+ 2
Me-bpy-me-bpy
MeHyamCl
MeHyamH
MeHyamMe
MeHyamN02
MeHyamOMe
4’-MeL
hPiS
Htrz
htt
HyamH
HyamN02
HyamOMe
i-biq
imid
imPY
i-nit
i-nicam
ipa
3-I-py
Ll
L2
L3
L4
L-LH
p-nitrophenylhydroxamato
p-methoxyphenylhydroxamato
ar-(phenylazo)acetaldoximato-N, N ”
a-(phenylazo)benzaldoximato-N,
N ”
(r-( p-tolylazo)benzaldoximato-N,
N ”
cr-(phenylazo)-p-tolualdoximato-N,
N ”
1,4-di(2,6-dimethyl-phenyl)-1,4-diazabutadiene
5,6-dihydro-l,lO-phenanthroline
3,4-dihydro-1(2-pyridyl)-isoquinoline
1,2,4-triazole cation ( + H)
1,4-di( p-tolyl)-1,4diazabutadiene
phenylhydroximato
p-nitrophenylhydroximato
p-methoxyphenylhydroximato
3,3’-biisoquinoline
imidazole
pyridyl-2-imine
isonicotinic acid
isonicotinic acidamide
isopropylideneamido anion
3-iodo-pyridine
cr-(phenylazo)acetaldoxime-N, N”
cr-(phenylazo)benzaldoxime-N, N ”
a-( p-tolylazo)benzaldoxime-N,
N ”
cw-(phenylazo)-p-tolualdoxime-N, N ”
1,3,5,7-tetrakis(2-(4-sec-butylpyridyl)imino)benzodi-pyrrole-anion
N-methyl-4,4’-bipyridine
6-methyl-2,2’-bipyridine
N-( 3-pyridyl)cinnamamide
1,4-di(3,5-dimethyl-phenyl)-2,3-dimethyl-l,4-diazabutadiene
2-( 3-tolyl-azo)pyridine
See figure
See figure
1,2-bis[4-(4’-methyl-2,2’-bipyridyl)
Jethane
N-methyl-p-chlorphenylhydroxamato
N-methyl-phenylhydroxamato
N-methyl-p-tolylhydroxamato
N-methyl-p-nitrophenylhydroxamato
N-methyl-p-methoxyphenylhydroxamato
1,3-bis(2-(4-methylpyridyl)imino)isoindolinato
249
70
248
200
2-meo-phen
MMCH
mmd
142
6
78
249
69
73
83
197
152
198
I83
140
7
I34
2-m-napy
4-mo-bpy
4-MoPh-phen
MPCH
2-m-phen
4-m-phen
5-m-phen
147
102
NM1
NOphen
81
203
204
205
255
5-n-phen
NPP
OBzim
OBzimH
OMCH
128
165
172
173
161
132
130
71
262
133
166
68
110
4’-OMe-stylb
opdi
PBzim
PBzimH
PC2
p-CHZ-cinn
p-cinn
Pc-phen
9-PDP
p-fum
phedi
phen
phen-dione
*PP
m-trz
mtt
NA
napy
4-n-bpy
N-Me-py
2-methoxy-l,lO-phenanthroline
See figure
1,4-di(2,6-dimethyl-phenyl)-2,3-dimethyl-l,4-di
azabutadiene
2-methyl-1,8_naphthyridine
4-methoxy-2,2’-bipyridine
4-p-methoxyphenyl-l,lO-phenanthroline
See figure
2-methyl-l,lO-phenanthroline
4-methyl-l,lO-phenanthroline
5-methyl-l,lO-phenanthroline
1,4-diphenyl-2,3-dimethyl-1,4_diazabutadiene
4-methyl-1,2,4-triazole
l&di( p-tolyl)-2,3-dimethyl-1,4-diazabutadiene
2-((4-nitrophenyl)azo)pyridine
1,8-naphthyridine
4-nitro-2,2’-bipyridine
N-(4-pyridyl)-&(3-Nmethylpyridyl)acrylamide(PF,)
N-methyl-imidazole
2,2’,2”-tris((l,lO-phenanthrolin-2yloxy)ethyl)amine
5-nitro-l,lO-phenanthroline
2-(3-nitrophenyl)-pyridine
2-( o-hydroxyphenyl)-benzimidazolate
anion
2-( o-hydroxyphenyl)-benzimidazole
4,7-dimethyldibenzo[3,2-b
: 2’,3’j][l,lO]phenanthroline
4’-methoxy-truns-4-stilbazole
o-phenylenediimine
2-(2-pyridyl)benzimidazolate
anion
2-(2-pyridyl)benzimidazole
bis-(4-pyridyl)-acetylene
N-(4-pyridylmethyl)cinnamamide
N-(4-pyridyl)cinnamamide
N-n-propyl-l,lO-phenanthroline-2-carboxamide
9-phenyldipyrido[3,2-a : 2’,3’-c]phenazine cation
N-(4-pyridyl)fumaramide
ethylester
o-phenanthroline-5,6-diimine
l,lO-phenanthroline
l,lO-phenanthroline-5,6-dione
250
88
74
84
213
214
4,7-Ph ,-phen
4-Ph-phen
5-Ph-phen
PhTROCl
PhTrOCOOEt
212
211
215
153
118
170
171
244
112
185
33
141
246
48
PhTROH
PhTROMe
PhTRON02
Ph- trz
pit
Pim
PimH
188
156
149
124
111
I37
180
135
136
169
247
65
66
138
117
139
144
145
11
126
125
PTPI
PTZ
PVI
PVP
Piq
PMA
pmth
4,4’-poeg-bpy
PPYZ
Pq
P(St-Vbpy)
PY
PYd
PYdiPY
PYm
PYmH
PYmi
PYnaPY
4-py-prim
Gpy-prim
PYr
3-PYr-PY
PY=c
PZ
PZH
6-sty-bpy
c-stylb
t-stylb
4,7-diphenyl-l,lO-phenanthroline
4-phenyl-l,lO-phenanthroline
5-phenyl-l,lO-phenanthroline
1-phenyl-3-p-chlorphenyltriazene-l-oxidato
1-phenyl-3-p-carboxyethylphenyltriazene-loxidato
1-phenyl-3-phenyltriazene-1-oxidato
1-phenyl-3-p-tolyltriazene-l-oxidato
1-phenyl-3-p-nitrophenyltriazene-l-oxidato
4-phenyl-1,2,4-triazole
4-methyl-pyridine
2-( 2-pyridyl)imidazolate anion
2-(2-pyridyl)imidazole
l-(2-pyridyl)-isoquinoline
2-aminomethylpyridine
2-( 2-pyridyl)-4-methyl- thiazole
See figure
pyridd2,3-blpyrazine
2-(2-pyridyl)-quinoline
styrene/4-methyl-4’-vinyl-2,2’-bicopolymer
pyridine
2-p- tolyl~pyridinecarboxaldimine
phenothiazine
polyvinylimidazole
poly(4-vinylpyridine)
pyridine
pyridazine
l-(2-pyridyl)-3,5-dimethyl-pyrazole
pyrimidine
protonated pyrimidine
N-methyl-( 2-pyridyl)-imine
2-(2-pyridyl)-1,8-naphthyridine
4-methyl-2(2’-pyridyl)-pyrimidine
6-methyl-4-(2’-pyridyl)-pyrimidine
pyrazine
3-(pyrrol-l-ylmethyl)-pyridine
pyrazine carboxylate
pyrazole anion
pyrazole
6-p-styryl-2,2’-bipyridine
c-stilbazole
t-stilbazole
251
103
109
122
9
184
55
253
100
101
12
75
254
286
282
281
151
150
283
47
46
148
123
TAP
taphen
t-bupy
4- tep-bpy
thpy
tm-bpy
TMCH
tml-phen
tm2-phen
Gtol-bpy
4- tol-phen
TPCH
TPTZ
tro
trpy
trz
trza
tsite
VB
v-bPY
Viz
4-VPY
Unnumbered
2SA
2SB
2sc
2SD
aca
ADP
AN
BA
BBB
Bit
Br
Cl
CL0
CN
co
DAC
DAM
1,4,5,8_tetraazaphenanthrene
dipyrido[3,2-c: 2’,3’-ejpyridazine
4-tert-butyl-pyridine
4-( triethylphosphonio)-2,2’-bipyridine
2-(2’-thiazolyl)-pyridine
4,4’,5,5’-tetramethyl-2,2’-bipyridine
See figure
3,4,7,8-tetramethyl-l,lO-phenanthroline
3,5,6,8-tetramethyl-l,lO-phenanthroline
6-p-tolyl-2,2’-bipyridine
4-tolyl-l,lO-phenanthroline
See figure
2,4,6-tripyridyl-s-triazine
4’-phenyl-2,2’,2”-tripyridine
2,2’,2”-tripyridine
1,2,4-triazole
1,2,4-triazole anion
4,4’,4”-triphenyl-2,2’,2”-tripyridine
polymeric v-bpy ligand
4-vinyl-4’-methyl-2,2’-bipyridine
IV-vinyhmidazole
4-vinylpyridine
iigands
1,2-bis(methylthio)ethane
1,2-bis(ethylthio)ethane
1,2_bis(phenylthio)ethane
3,4-bis(methylthio)toluene
acetylacetonato anion
1,2-bis(diphenylphosphino)acetylene
acetonitrile
butylamine
tributylphosphine
benzyl isocyanide
bromide anion
chloride anion
perchlorate anion
cyanide ion
carbonyl
trans-1,2-diamminocyclohexane
1,2-diamino-%-methyl-propane
252
dia
dmp
ECN
EDP
en
For
gly
H
H2
H20
Hed
I
IPA
iPP
MDP
MeP
MMP
MPc
MPP
N3
NO
NO2
nor
OH
ON1
ON2
ON3
ON4
ox
Pas
PCN
PDA
PDP
PEA
PMA
PPP
PRC
PSB
P-IS
SCN
SEE
SF
o-phenylenebis( dimethylarsine)
1,2-bis(diphenylphosphino)ethane
acrylonitrile
cis-1,2-bis(diphenylphosphino)ethylene
1,2_ethylenediamine
formiate anion
glycinate anion
hydride anion
di-hydrogen
water
H,-ethylenediaminetetraacetate
iodide anion
isopropylamine
isonitrosopropiophenonato anion
l,l-bis(diphenylphosphino)methane
tritolylphosphine
dimethyl-phenyl-phosphine
4-methoxyphenylcyanide
methyl-diphenyl-phosphine
azide anion
nitrosonium cation
nitrite anion
norbornadiene
hydroxide anion
methylnitrite
ethylnitrite
n-butylnitrite
i-propylnitrite
oxalate anion
triphenylarsine
benzonitrile
l,l-bis(diphenylarsino)methane
1,3-bis( diphenylphosphino)propane
3-amino-1-propene
benzylamine
triphenylphosphine
butyronitrile
triphenylstibine
p-toluol-sulfonate anion
thiocyanate anion
diethylsulfide
pentafluorothiophenolato anion
253
dimethylsulfide
methyl-phenylsulfide
2-(methylthio)l-aminoethane
2-(benzylthio)-1-aminoethane
2-(phenylthio)-1-aminoethane
&(methylthio)-quinoline
8-mercaptoquinoline anion
2-(methylsulfinyl)-1-aminoethane
thiophenolato anion
pyrrolidinecarbodithionato anion
diethyldithiocarbamato anion
dimethyldithiocarbamato anion
ethylxanthato anion
trifluoroacetate anion
propylenediamine
thiourea
SMM
SMP
SNA
SNB
SNC
SND
SNE
SNO
SP
SSB
SSE
SSM
sso
TFA
Structural formulae of the ligands
13 R = CH,
14
1 R-H
2 R = Cl
3R=Br
4 R = NH2
5 R=
N(CH312
6 R = OCH,
7 R = NO,
9 R=
OCH&H,
9
R=
P(C,H&?
Q-Q
R
10
R = CH3
11
R = -~_CH=CH=
12
R
= aCH3
R = COO-CH’
CH3
‘CH,
15 R = CH3
16 R = Cl
17 R=Sr
18 R = NO2
19 R = NH2
20 R = S03H
21
22
23
24
25
26
27
28
29
30
31
32
33
R = NQH&
R - NHCOCH3
R = 0C2H,
R = 0C6Hs
R = 0CHpC6H,
R = C,H,
R - CH2GHs
R = CH =CHC6Hb
R=COOH
R = C(CHO13
R = C,H,
R = COOCmH3,
R =VO\rO..pOCHl
= COOCH3
34R
35 R = CONHC12Ha
254
36
R -
37
R = COOCzHS
CONHC,H,,
38
R = COO-CH
39
R =cOo~
/CH3
.cti
58
3
Q-q-=
40
R, - R2 =COOCH2C6HB
41
R, = RP -COO
42
R,=R2-COO
43
Rq =R@X%
44
45
46
47
48
R, = R,=CON(C2
HII
R1 = COOH , R2 = CH,
R, =CH=CH2,R
= CH,
Rl -- cCH-CM2 P,,R2 = CH3
as47,copolymer
wlth
styrene
R, = COOH
49
R,=CONH
_80
[&-J]
_s+
N
62
R =CH,
e(kH-CH2);
copolymer
with
N -vinyl pywlidone
50
51
52
R =CH3
R =COOC2H6
R =NHCOCH3
53
R ‘COO-CH<$
65
c.H3
Q-Q
C”3
54
3
68
69
70
71
R=H
R=CHQ
R = OCH,
R * CONHC3H,
255
96
72
73
R-Cl
R=CH3
74
R = C&IS
75
RteCH3
76
R=M
77
R=eBr
78
R =+OCH,
R,=M
R,=eOCH,
97
R,=M
R2=CBHB
98
R, =eBr
R,=-Q_OCH3
R
79
80
R=CI
R=Br
61
82
R=N02
R = NH2
83
84
R = CH,
R = C6H6
86
87
R = CH3
R=CL
88
R = C6H5
89
R =eBr
90
R =oOCH3
91
R=M
92
R-as03
93
R =+CH3
94
R,* R2 -OH
95
R,=w
R2=eBr
H3CHmW3
100
cl- -
N
103
256
120 R = COOH
NC
CN
NC-
121 R = CONH2
-CN
122 R = C(CH313
123 R = CH=CH,
124 R =
GH-CH2kn
polymeric form
125
3-
N’ \
‘C-H
/
\
d -
IN’
c-l
R
112 R = CH,NH,
113 R = CH,CH2NH,
r,’ R
C-T
114
R = Cl
115 R =
I
116 R = CH2C&NH2
117 R = CH2-ND
R
IN
r,
’
116 R = CH3
119 R = COCH,
127
R = Cl
129
R = OCH,
129
R = CN
257
134
/J;,
P
/”
0‘/
136
N
146
rN’
P
3
p3
137
0‘J
N
147
0N
0I
'N
138
T48
1;:_@
(1
47~ -CH~+
/;
c,
139
polymeric form
N
149
a’
I
N'
140
“&a
H
7-Y H
-(I$
R
142
151 R-H
”
3
cJ32cH
143
3
152 R = CH,
153 R = C6H,
154 R = C”,-CH=CH~
258
1
L-N +
“<,>”
t
[
155
c&3
s
N
I)
HN
NH
c?-dH
-
\N/
A
156
v
167
NH
166
NiC=Ca
161
172
R=e~H3
164
HN
NH
165
3
175
monopmtommtedform of 174
176
bipm&utod
fotm Or 174
259
&y
190
pmtaeut& form d 189
191
R
192
praweod
.
C,“,
lorm of 191
177
178
monopmtonrtd farm of 177
179
bipretonatad Eorm of 177
G”3
QN$_
3
R@%QR2
193
R,-
194
pmtomlrd
CH,
195
R,=
196
p&avutd
R3=
form
H
N
-
181
R
=H
182
R
= CH3
197
R
=
I4
“8
184
R=H
c”3
185
R
200
R = CH3
201
R=H
=CH3
(=&i/-L
189
R
= CH3
193
R2=CH3
fcwm of
R
&g
H
of
195
260
235 Rl = R2= CH,
protonated form of 235
239
R, = CH2C34,P@H3
Rl = CHaCH3,Rz-
H
R, = CH,CH,,R$Cl
209
R, = CH,CH,~COOCH&H,
210
R, = CH&H3qI+J02
211
R, = CsHsRz=
CHa
212
R, = C, Hs ,R,=
H
213
R, = C,
Hs,R2=
Cl
214
R, = C,
H, ,R2= Co0cH&H,
215
R, = C,
H,,R2=
= H , R,=
237
R, = CH2CHB R&ZH,
233
protonated form of 237
239
R, = 0
R2=CH,
240
potonatsd
form
241
R, = 0
R,=
230
NH2
NO,
0CH3
2-M
R,
217
R, = H,R2=CH3
qR2= H
218
R,
219
R, = H,R2=CI
220
R, = H.R,=
221
R,
= CH3 ,R,=OCH,
222
R,
= CH,
223
R,
=CH,,R2=H
224
R,
= CH3
,R2=CI
225
R,
= CH,
,R2=N02
No2
,R,=CH,
/-\
-c-43
\N/
\/
244
226 R
of
=OCH3
227 R =H
228 R = NO,
245
229
R,=H
R,o
/\
Q
230
pmtamted form of 22s
231
R, = CH,
232
protonated form of 23-i
233
R, =R2=
234
protcnuted form of 233
w
249
R2=o
0
fl
247
248
R = CHB
249
R =
0
250
R=H
251
R
= CHJ
252
R
=
253
R
= CHJ
254
R
=
0
/\
CHzl
&$g
255
257
R=H
258
R = CH,
p&=p
259
265
R = CH,CH,
286
R = CH,CH,CH,
27-l
R =(CH,),
272
R =(CH&
267
273 R =ca+&~(CH&
274
R =(CH,),,
268
277
270
278
263
279
-0
285
I
281 R,= R,= Rsf H
282 R, =o,Rg
R3, H
Other abbreviations
1,2-dme
AC. anh.
AgRE
AN
BN
BzOH
DMF
DMSO
E/p,a
E/p,c
eglyc
EPA
EtCN
EtOH
Fc+/O
i, irr
iBN
MeOH
1,2-dimethoxyethane
acetic anhydride
Ag reference electrode
acetonitrile
benzonitrile
benzil alcohol
dimethylformamide
dimethylsulfoxide
anodic peak potential
cathodic peak potential
ethyleneglycol
ether/&-pentane/ethanol
ethyl cyanide
ethanol
ferrocenium/ferrocene
irreversible
isobutyronitrile
methanol
(5 : 5 : 2)
264
mer
MF
NaLS
NHE
nitrile
PC
PMM
SCE
SSCE
surf
THF
meridional
IV-methylformamide
sodium laurilsulfate
normal hydrogen electrode
propionitrile/butyronitrile
(4 : 5)
propylene carbonate
polymethylmethacrylate
saturated calomel electrode
sodium saturated calomel electrode
surface
tetrahydrofuran
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