1
IDW 2002
Friday, October 25th, 2002
19:00-22:00. Registration and Mixer
David Thomson House, McGill University, 3650 McTavish Street.
The scientific sessions will take place in rooms K-500 and M-415
in the Pavillon Principal at the Université de Montréal
Saturday, October 26th, 2002
9:00-10:00.
Plenary Lecture:
Professor William D. Jones, Department of Chemistry, University of Rochester,
Rochester, NY , USA.
10:30-16:30. Oral Presentations
16:50-18:30. Poster Session
19:30-22:00. Banquet and Poster Presentations Awards
Faculty Club, McGill University, 3450 McTavish Street.
Sunday, October 27th, 2002
9:30-10:50.
Oral Presentations
11:10-11:40. Guest Speaker:
Professor D. Scott Bohle, Department of Chemistry, McGill University
11:40-12:10. Closing Remarks and Oral Presentations Awards
Bienvenue à Montréal!
Welcome to Montreal!
2
Saturday Morning
9:00-10:00. Room K-500. Plenary Lecture.
Alkane Complexes as Intermediates in C-H Bond Activation
Reactions
William D. Jones
Department of Chemistry, University of Rochester, Rochester, NY 14627
jones@chem.rochester.edu
10:00-10:30. Coffee Break
Session I (Room K-500)
Session Chair: Annie Michaud
10:30-10:50. K-1. Manganese(II) Dipyrrolides as a Model System for
Small Molecule Activation
Patrick Crewdson, Sandro Gambarotta, and Glenn Yap
Department of Chemistry, University of Ottawa
10:50-11:10. K-2. Kinetic and Computer Modeling Studies into the
Hydrogenation of Acetophenone by the Novel Hydrido amido
Catalyst RuH(NHCMe2CMe2NH2)(PPh3)2
Sean Clapham, Kamaluddin Abdur-Rashid, Alan Lough, and Bob
Morris
Department of Chemistry, University of Toronto, Toronto, Ontario,
Canada
11:10-11:30. K-3. Synthesis and Reactivity of Manganese Complex
Derived of Methylcymantrene
Y. Ortin1, N. Lugan1, R. Mathieu1, M. J. McGlinchey2
1
Laboratoire de Chimie de Coordination du CNRS, UPR CNRS 8241,
Toulouse, France. 2 Department of Chemistry, McMaster University,
Hamilton, Ontario, Canada
11:30-11:50. K-4. Potential Energy Surfaces in Transition States for
Associative Reactions of Metal Carbonyl Clusters with P-donor
Nucleophiles: Rh4(CO)12
Kevin Bunten, David H. Farrar, and Anthony J. Poë
Department of Chemistry, University of Toronto, Toronto, Ontario,
Canada
11:50-14:00. Lunch Break
Session II (Room M-415)
Session Chair: John Grey
10:30-10:50. M-1. Anion-dependent structures of noble-metalcomplexes of blue-luminescent starburst ligands
Corey Seward, Emily Mitchell, Wenli Jia, and Suning Wang
Department of Chemistry, Queen’s University, Kingston, Ontario
10:50-11:10. M-2. Photoswitching hydrogen-bonded azodibenzoic
acid derivatives
Felaniaina Rakotondradany, Tony Whitehead, and Hanadi F. Sleiman.
Department of Chemistry, McGill University, Montreal, Quebec,
Canada
11:10-11:30. M-3. Phase Transitions in the Superionic Pb1-xSnxF2
Solid Solution upon Ball-Milling
Georges Dénès , Matthieu Kernec, M. Cecilia Madamba and Marc
Poizat
Department of Chemistry and Biochemistry, Laboratory of Solid State
Chemistry and Mössbauer Spectroscopy, Laboratories for Inorganic
Materials, Concordia University, Montréal, Québec, Canada
11:30-11:50. M-4. Modern Semiempirical SCF MO Methods in
Inorganic Chemistry
S. I. Gorelsky1, 2, and A. B. P. Lever2
1
Department of Chemistry, Stanford University, Stanford, California,
U.S.A. 2 Department of Chemistry, York University, Toronto, Ontario,
Canada
11:50-14:00. Lunch Break
Saturday Afternoon
Session III (Room K-500)
Session Chair: Laurent Groux
14:00-14:20. K-5. Direct Evidence for the Stereochemistry of
Transmetalation and Reductive Elimination Processes in Pdmediated P–C bond formation
Tim J. Brunker,1 Jillian R. Moncarz,2 David S. Glueck,1 Roger D.
Sommer,3 and Arnold L. Rheingold3
1
Department of Chemistry, Dartmouth College, Hanover, NH, 03755,
USA.
2
Current address: Department of Chemistry, Marietta College,
Marietta, OH, 45750, USA. 3 Department of Chemistry, University of
Delaware, Newark, DE 19716, USA.
14:20-14:40. K-6. The Palladium Catalyzed Multicomponent
Synthesis of Heterocyclic and Amino Acid Based Products
Ragiv Dhawan, and Bruce A. Arndtsen*
Department of Chemistry, McGill University, 801 Sherbrooke Street
West, Montreal, Quebec, Canada.
14:40-15:00. K-7. Synthesis and Unusual Skeletal Substitution
Chemistry of Aluminatophosphazenes: A Versatile Class of
Inorganic Heterocycles
Eric Rivard, Andrew R. McWilliams, Alan J. Lough, and Ian Manners
Department of Chemistry, University of Toronto, Toronto, Ontario,
Canada
15:00-15:20. K-8. Spectroscopic and Computational Assessment of
the Rotational Barrier of a Ferrocenyl-Stabilized Cyclopentadienyl
Cation: Evidence for the First Hydroxy-Fulvalene Ligand
Laura E. Harrington,1 Ignacio Vargas-Baca,1 and Michael J.
McGlinchey1,2
1
Department of Chemistry, McMaster University, Hamilton, Ontario,
Canada. 2 Department of Chemistry, University College Dublin, Dublin,
Ireland
15:20-15:50. Coffee Break
Session Chair: Olivier Bourrier
15:50-16:10. K-9. Low valent actinide complexes in molecular
activation processes. Synthesis and Reactivity of U(III) and Th(II)
polypyrrolides.
Ilia Korobkov, Sandro Gambarotta, Glenn P. Yap
Department of Chemistry, University of Ottawa, Ottawa, Ontario,
Canada
16:10-16:30. K-10. Me2Al-CH2-PMe2 : A New, Bifunctional CoCatalyst in the Ni(II)-Catalyzed Oligomerization of PhSiH3
Frédéric-Georges Fontaine, and Davit Zargarian*
Département de Chimie,Université de Montréal, Montréal (Québec),
Canada H3C 3J7
16:30-16:50. Poster Synopses
3
16:50-18:30. Poster Session
Session IV (Room M-415)
Session Chair: Rémi Beaulac
14:00-14:20. M-5. Metal-Metal Coupling in Asymmetric Dinuclear
Mixed-Valence Ruthenium Complexes
Joseph Kahenya and Robert.J.Crutchley*
Ottawa-Carleton Chemistry Institute, Department of Chemistry,
Carleton University, Ottawa, Ontario, Canada
14:20-14:40. M-6. Anticeramic Yield: Ceramic Precursors in
Polymer-Assisted Vapour Deposition versus Classical Polymeric
Route
Sanela Martic*, Nathalie Camire**, Eric Gagnon*, Abdelatif Jaouad**,
Cetin Aktik** and Mihai Scarlete*
* Bishop's University, Lennoxville, Quebec, Canada, **Universite de
Sherbrooke, Sherbrooke, Quebec, Canada
14:40-15:00.
M-7.
Tuning
the
Luminescence
and
Electroluminescence of Diphenylboron Complexes of Substituted 2(2'-Pyridyl)indoles
Qinde Liu1, Maria S. Mudadu2, Randolph Thummel2, Ye Tao3, and
Suning Wang1
1
Department of Chemistry, Queen’s University, Kingston, Ontario, K7L
3N6, Canada. 2 Department of Chemistry, University of Houston,
Houston, Texas 77204-5003, USA
3
Institute for Microstructural Sciences, National Research Council, 100
Sussex Drive, Ottawa, K1A 0R6, Canada
15:00-15:20. M-8. Scavenging with TEMPO to Identify Peptideand Protein-based Radicals by Mass Spectrometry: Advantages of
Spin Scavenging over Spin Trapping
P. John Wright and Ann M. English*
Department of Chemistry and Biochemistry, Concordia University, 1455
de Maisonneuve Boulevard West, Montreal, Quebec, Canada
9:30-9:50. K-11. A Three-Coordinate Iron Hydride Complex as a
Model for Reactive Intermediates of the Enzyme Nitrogenase
Jeremy M. Smith, Rene J. Lachicotte, and Patrick L. Holland
Department of Chemistry, University of Rochester, Rochester, NY, USA
9:50-10:10. K-12. Solid State Structures of Oligonuclear Ruthenium
Light Harvesting Arrays
Matthew Polson2, John Lotoski1, Olof Johansson1 Nicholas Taylor1, and
Garry Hanan2
1
Department of Chemistry, University of Waterloo, Waterloo, Ontario,
Canada. 2 Département de Chimie, Université de Montréal, Montréal,
Quebec, Canada
10:10-10:30. K-13. Synthesis and Application in Catalysis of New
Versatile Dendritic Architectures Built Using a Simple Divergent
Methodology
Olivier Bourrier and Ashok K. Kakkar.
Department of Chemistry, McGill University, Montreal, QC, Canada
10:50-11:10. Coffee Break
Session II (Room M-415)
Session Chair: Adam Dickie
9:30-9:50. M-11. The Synthesis, Characterization, and
Bioconjugation of Tc/Re Metallocarboranes
O.O. Sogbein, P.Morel, and J.F. Valliant
Department of Chemistry, McMaster University, Hamilton, Ontario,
Canada
9:50-10:10. M-12. Kinetics and Mechanisms of Abiotic Methylation
of Aqueous Mercury
Valbona Celo and Susannah Scott
Department of Chemistry, University of Ottawa, Ottawa, Canada
10:10-10:30. M-13. S-Nitrosation of Recombinant Calbindin D28K
From Human Brain Mediated by Cu,Zn Superoxide Dismutase
Limei Tao and Ann English*
Department of Chemistry and Biochemistry, Concordia University,
1455, de Maisonneuve Blvd. W., Montreal, Quebec, Canada
15:20-15:50. Coffee Break
Session Chair: François Baril-Robert
15:50-16:10. M-9. Synthesis and Characterization of PhosphidoCoated Gold Nanoclusters
Diana M. Stefanescu, and David S. Glueck*
Department of Chemistry, Dartmouth College, Hanover, NH, USA
16:10-16:30.
M-10.
Optical
Properties
of
Er3+-Doped
Nanocrystalline Gd2O3
Fiorenzo Vetrone1, John-Christopher Boyer1, John A. Capobianco1,
Adolfo Speghini2 and Marco Bettinelli2
1
Department of Chemistry and Biochemistry, Concordia University,
1455 de Maisonneuve Blvd. W., Montreal, Quebec, Canada, H3G 1M8. 2
Dipartimento Scientifico e Tecnologico, Università di Verona, and INSTM,
UdR Verona, Ca' Vignal, Strada Le Grazie 15, I-37134 Verona, Italy
16:30-16:50. Poster Synopses
16:50-18:30. Poster Session
19:30-22:30. Banquet
Sunday Morning
Session V (Room K-500)
Session Chair: Ragiv Dhawan
10:30-10:50. M-14. The Doubly Disordered Ba1-xSnxCl1+yF1-y Solid
Solution: The First Example of a Mixture of Sn2+ Stannous Ions and
Covalently Bonded tin(II) in the Same Material
Georges Dénès and Abdualhafeed Muntasar
Department of Chemistry and Biochemistry, Laboratory of Solid State
Chemistry and Mössbauer Spectroscopy, Laboratories for Inorganic
Materials, Concordia University, Montréal, Québec, Canada
10:50-11:10. Coffee Break
Closing Session (Room K-500)
Session Chair: Hassan S. Bazzi
11:10-11:40. K-14. Chemical Biology of Nitric Oxide and its
Electrophilic Addition Products:
New Access to ONNO
Frameworks
Navamoney Arulsamy1, D. Scott Bohle2, and Jerome Imonigie1
1
Department of Chemistry, University of Wyoming, Laramie, Wyoming,
USA. 2 Department of Chemistry, McGill University, Montreal, Quebec,
Canada
11:40-12:10.
Closing
Remarks
and
Presentations
Awards
4
ABSTRACTS OF ORAL PRESENTATIONS
K= Room K-500, M= Room M-415
Plenary Lecture:
Alkane Complexes as Intermediates in C-H Bond Activation Reactions
William D. Jones
Department of Chemistry, University of Rochester, Rochester, NY 14627 jones@chem.rochester.edu
A series of alkyl hydride complexes have been studied of the type Tp'Rh(L)(R)(H) where L=neopentylisocyanide and R=Me,
Et, n-Pr, n-Bu, i-Pr and s-Bu. The secondary alkyl complexes are found to rearrange to primary alkyl complexes prior to
elimination of alkane. Stereochemical probes are used to investigate the reversibility of the C-H bond-forming/bond-cleavage
steps of the reactions. Deuterium labeling is used to monitor the rearrangements, and the isotope effect for reductive bond
formation is determined. Activation of the C-H/C-D bonds in CH2D2 is examined to probe the kinetic selectivity for oxidative
bond cleavage. These results are combined to give an overall picture of the energetics of C-H bond activation in which the
(commonly observed ) inverse equilibrium isotope effect arises as a result to two opposing normal kinetic isotope effects. A
summary of the relative rates of oxidative bond cleavage, migration, and alkane dissociation will be presented and compared
with other observations in the literature. Relative rates of activation of several alkane C-H bonds will be compared. In
addition, new results on the relative coordination ability of different types of C-H bonds will be presented.
D
kRED
CH3
kOAD
[Rh]
D
[Rh]
fast
H
[Rh]
CDH2
CH3
kd
3kOAH
kREH
H
[Rh]
CDH2
[Rh] + CH3D
K-1. Manganese(II) Dipyrrolides as a Model System for Small Molecule Activation
Patrick Crewdson, Sandro Gambarotta, and Glenn Yap
Department of Chemistry, University of Ottawa
An exciting field of study which is currently being undertaken in the literature is that of the photo-oxidation of water. This
process, which is mediated by a poorly known manganese (II) tetrameric μ-oxo bridged complex, as well as a complex
protein structure, could conceivably lead to a cheap and abundant fuel source. To this end we have endeavored to explore the
synthesis of manganese clusters in order to model the behaviour of the tetramer core of the active enzyme. Manganese (II)
alkyls were successfully made as precursors for assembling cluster structures. Though manganese alkyls are not unknown in
the literature there are very few reported syntheses. We were able to synthesize several novel and readily available
Manganese (II) alkyls. By combining the Manganese dialkyls with dipyrrolide ligands several dimeric and octameric clusters
were prepared. Crystal structures and magnetic properties, as well as preliminary insights into their chemical behaviour will
be discussed.
5
K-2. Kinetic and Computer Modeling Studies into the Hydrogenation of Acetophenone by the Novel Hydrido-amido
Catalyst RuH(NHCMe2CMe2NH2)(PPh3)2
Sean Clapham, Kamaluddin Abdur-Rashid, Alan Lough, and Bob Morris
Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
The first amino-amido hydride complex RuH(NHCMe2CMe2NH2)(PPh3)2 (1) has been structurally characterized. The kinetic
studies of the hydrogenation of acetophenone catalyzed by 1 in C6D6 under hydrogen gas are presented. A computer model
of the mechanism of hydrogenation is discussed. Both kinetics and model show that the addition of dihydrogen to the Ru=N
bond is the rate determining step. The formate compound RuH(HCOO)(tmen)(PPh 3)2 models the transition state for the
hydrogenation of the ketone. 1 reacts with several weakly acidic reagents.
K-3. Synthesis and Reactivity of Manganese Complex Derived of Methylcymantrene
Y. Ortin1, N. Lugan1, R. Mathieu1, M. J. McGlinchey2
1
Laboratoire de Chimie de Coordination du CNRS, UPR CNRS 8241, Toulouse, France
2
Department of Chemistry, McMaster University, Hamilton, Ontario, Canada
Non-heteroatom substituted carbene complexes play a key role both as reagents and as catalysts in organic synthesis:
cyclopropanation of alkenes, ring-opening metathesis polymerization (ROMP), or ring-closing metathesis (RCM), etc. In this
context, the reactivity of new non-heteroatom substituted carbene complexes of manganese, and particularly propynylidene
complexes of the type MeCp(CO)2Mn=C(R')C≡CR", was investigated. The first part of this work deals with the protocol set
up to prepare non-substituted-carbene complexes of manganese in particular manganese propynylidene complexes. In second
part, we present the dynamic behaviour of polynuclear complexes resulting from the coordination of additional [Co 2(CO)6] or
[MeCp(CO)2Mn] fragments to the alkyne moiety of the manganese propynylidene complexes. This study allowed us to
observe unprecedented fluxional processes: on the one hand, dynamic equilibration of eta1-carbene and eta2-alkyne moieties
and on the other hand, rapid migration of the carbene fragment over the three carbonyl ligands.
1. Y. Ortin, Y. Coppel, N. Lugan, R. Mathieu, M. J. McGlinchey J. C. S., Chem. Comm. (2001), 1690-1691.2. Y. Ortin, Y.
Coppel, N. Lugan, R. Mathieu, M. J. McGlinchey J. C. S., Chem. Comm. (2001), 2636-2637.
K-4. Potential Energy Surfaces in Transition States for Associative Reactions of Metal Carbonyl Clusters with Pdonor Nucleophiles: Rh4(CO)12
Kevin Bunten, David H. Farrar, and Anthony J. Poë
Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
The metal carbonyl cluster Rh4(CO)12 reacts with a wide variety of P-donor nucleophiles solely by an associative mechanism,
and the rate constants can be analyzed quantitatively according to the electronic and steric properties of the nucleophiles. It is
clearly necessary to include what has become known as the "Aryl Effect" in these analyses, together with positive
contributions to the rates of -acidity effects due to phosphite nucleophiles. These results provide the basis for general
method of assessing the ways in which such results can provide a rationale for methods of tuning catalysts for optimum
performance.
CO
OC
CO
CO
OC
O
CO
PZ3
OC
O
O
OC
O
CO
CO
Rh
Rh
CO
C
Rh
Rh
O
CO
O
OC
CO
Rh
Rh
OC
PZ3
C
C
CO
OC
CO
CO
PZ3
OC
C
CO
Rh
OC
Rh
Rh
C
OC
CO
Rh
Rh
OC
CO
Rh
O
OC
O
CO
6
K-5. Direct Evidence for the Stereochemistry of Transmetalation and Reductive Elimination Processes in Pdmediated P–C bond formation
Tim J. Brunker,1 Jillian R. Moncarz,2 David S. Glueck,1 Roger D. Sommer,3 and Arnold L. Rheingold3
1
Department of Chemistry, Dartmouth College, Hanover, NH, 03755, USA.
2
Current address: Department of Chemistry, Marietta College, Marietta, OH, 45750, USA.
3
Department of Chemistry, University of Delaware, Newark, DE 19716, USA.
DiPAMP (1,2-bis[(o-methoxyphenyl)phenylphosphino]ethane) is an industrially important chiral ligand for asymmetric
hydrogenation reactions, and can be synthesized in chirally pure form from the corresponding chiral tertiary phosphineborane P(o-An)(Me)(Ph)(BH3) (o-An = 2-methoxyphenyl). A series of Pd(diphos*)(o-An)I complexes (diphos* = chiral
diphosphine ligand) have been screened as potential catalysts for the asymmetric synthesis of this precursor by coupling of oAnI and P(H)(Me)(Ph)(BH3). Pd[(R,St-Bu-Josiphos](o-An)I was found to be the most effective catalyst although only slight
enantio-enrichment of the obtained product was observed. Use of the complex Pd[S,S-Chiraphos](o-An)I did not lead to
catalytic turnover but instead gave the stable, seperable diastereomeric intermediates Pd[S,S-Chiraphos](oAn)[P(Me)(Ph)(BH3)] which have both been characterized by NMR and X-ray crystallography. Isolation of this intermediate
in the proposed catalytic cycle has allowed study of the stereochemistry of the fundamental steps in P—C bond formation.
Thus, heating a single diastereomer of this Pd complex in THF solution led to reductive elimination of P(oAn)(Me)(Ph)(BH3) with complete retention of configuration at the P center. Similarly, transmetalation at low T of
enantiopure samples of P(H)(Me)(Ph)(BH 3) with Pd[S,S-Chiraphos](o-An)I yields a single diastereomer of the Pd complex,
again with retention of configuration at P. This is the first time in which the stereochemistry of these processes in transition
metal mediated C—X bond-forming reactions has directly been established.
K-6. The Palladium Catalyzed Multicomponent Synthesis of Heterocyclic and Amino Acid Based Products
Rajiv Dhawan and Bruce A. Arndtsen*
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada.
The design of efficient methods to construct biologically relevent core structures is an important goal in synthetic organic
chemistry. One particularly attractive approach is to consider target products as being made up of multiple versions of basic
builiding blocks and using metal catalysis to “assemble” these individual components into the target structure . Described in
the talk will be our development of a metal catalyzed route to 1,3-oxazolium-5-oxides, using imines, CO and acid chloride as
building blocks. In addition, the development of a new catalytic route to a range of heterocyclic (ie. pyrroles and -lactams)
and peptide-based molecules (amido esters), will be discussed.
7
K-7. Synthesis and Unusual Skeletal Substitution Chemistry of Aluminatophosphazenes: A Versatile Class of
Inorganic Heterocycles
Eric Rivard, Andrew R. McWilliams, Alan J. Lough, and Ian Manners
Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
Recently we reported the synthesis of the 6-membered AlNP heterocycle [N(PCl2NMe)2AlMeCl] 1 by a novel atom
exchange reaction involving the boron precursor, [N(PCl2NMe)2BCl2], and AlMe3.1 In our attempts to generate a cationic
aluminum ring, we observed some interesting reactivity. For example, treatment of 1 with Ag[BF4] surprisingly gave the
fluorinated boron heterocycle [N(PCl2NMe)2BF2] 2. Therefore we can reversibly incorporate both Al and B atoms within a
phosphazene ring framewok using this rare skeletal substitution process. Subsequently we discovered that group 15 elements
can also be readily inserted in place of aluminum to give new heterophosphazene rings [N(PCl2NMe)2PnF4, Pn = P, As, Sb].
In addition, the reactivity of 2 towards various nucleophiles (e.g. MeLi) and electrophiles (e.g. ECl 3, E = B, Al, Ga) will be
discussed.
K-8. Spectroscopic and Computational Assessment of the Rotational Barrier of a Ferrocenyl-Stabilized
Cyclopentadienyl Cation: Evidence for the First Hydroxy-Fulvalene Ligand
Laura E. Harrington,1 Ignacio Vargas-Baca,1 and Michael J. McGlinchey1,2
1
Department of Chemistry, McMaster University, Hamilton, Ontario, Canada
2
Department of Chemistry, University College Dublin, Dublin, Ireland
Protonation of 3-ferrocenyl-2,4,5-triphenylcyclopentadienone with trifluoroacetic acid results in the formation of the first
hydroxy-fulvalene complex. The dramatic deshielding and decoalescence of the 1H and 13C NMR signals in the ferrocenyl
region offer evidence for the participation of the metal in stabilization of the positive charge, which results in restricted
rotation of the ferrocenyl group. As determined by NMR spectroscopy, the maximum barrier to rotation in the neutral
species is ca. 9 kcal mol-1, whereas the minimum barrier in the cation considerably exceeds 13 kcal mol -1. The difference in
rotational barriers for the neutral and protonated species is rationalized by using DFT calculations.
H
O
O
+
H
Fe
Fe+
8
K-9. Low valent actinide complexes in molecular activation processes. Synthesis and Reactivity of U(III) and Th(II)
polypyrrolides.
Ilia Korobkov, Sandro Gambarotta, Glenn P. Yap
Department of Chemistry, University of Ottawa, Ottawa, Ontario, Canada
In last few years great interest has arisen in the field of small molecule activation using organometallic complexes of the f –
block. While there have been several great breakthroughs in the chemistry of lanthanides, actinide chemistry remains
relatively unexplored, yet promising. There are a few reported examples wherein low valent U species were able to interact
with dinitrogen, which is considered to be one of the most inert target molecule. In our research project we explore the
possibility of using polypyrrole anions to stabilize low valent U and Th compounds, and examine the reactivity of the
resulting complexes. From the chemistry of lanthanides it is known that polypyrrole based ligands help to stabilize low
oxidation states because of their great variety of bonding modes and ability to retain alkali cations. Both of these factors
considerably affect the chemical transformation pathways. By reduction of the proper Th based precursor we were able to
isolate a compound in which the formal oxidation state of Th can be assumed as +2. However, the complex is diamagnetic as
expected for a Th(IV) metal center. Nevertheless, in the reaction with trimethylsilyl azide this complex behaves, as a two
electron reductant. This allows us to consider this compound as the first Th(II) organometallic synthon. In the case of the U
based precursor we were unable to isolate the low-valent intermediate. But when generated in situ, U(II) species are involved
in a wide variety of transformations including solvent fragmentation, silioxane depolymerization and dinitrogen cleavage.
These experiments allow us to better understand the stability and the reactivity of low valent actinide complexes and the
influence of reaction conditions on their chemical transformations. These discoveries will be used in the future to tune the
chemical behavior of these complexes.
K-10. Me2Al-CH2-PMe2 : A New, Bifunctional Co-Catalyst in the Ni(II)-Catalyzed Oligomerization of PhSiH3
Frédéric-Georges Fontaine, and Davit Zargarian*
Département de Chimie,Université de Montréal, Montréal (Québec), Canada H3C 3J7
The title compound (Me2AlCH2PMe2)2, 1, was prepared by Karsch et al. (Organometallics 1985, 4, 231.) but the
coordination chemistry of this potential ligand has not been explored. We discovered that the mixture of 1 with the nickel(II)
complex (1-MeInd)Ni(PPh3)Me (2) and an amine, gives the formation of complex 3 (1-Me-Ind)Ni(PMe2CH2AlMe2.Base)Me,
in equilibrium with the starting products. Compound 3 is 10 times more active than the previously characterized complex (1Me-Ind)Ni(PMe3)Me (4) in the dehydrogenative coupling of PhSiH3. This talk will elaborate on the different reactivities of 1
with nickel(II) indenyl complexes.
Al
P
P
Al
+
Ni
Ni
Ph3P
Me
P
Al
1
2
3
Me
Base
9
K-11. A Three-Coordinate Iron Hydride Complex as a Model for Reactive Intermediates of the Enzyme Nitrogenase
Jeremy M. Smith, Rene J. Lachicotte, and Patrick L. Holland
Department of Chemistry, University of Rochester, Rochester, NY, USA
In addition to catalytically reducing dinitrogen to ammonia, the enzyme nitrogenase also reduces protons to dihydrogen, and
acetylenes to cis-alkenes. Based on precedents from organometallic chemistry, low-coordinate iron hydrides may be reactive
intermediates in these reactions. We have th
-diketiminate ligand.
Given the wide range of three-coordinate iron complexes stabilized by this ligand, it is surprising that this complex is fourcoordinate the solid state. Spectroscopic and kinetic evidence suggests the presence of a monomeric, three-coordinate hydride
complex in equilibrium with the dimer in solution. Like the enzyme, the low coordinate hydride complex reduces protons to
dihydrogen and acetylenes stereospecifically to alkenes.
K-12. Solid State Structures of Oligonuclear Ruthenium Light Harvesting Arrays
Matthew Polson2, John Lotoski1, Olof Johansson1 Nicholas Taylor1, and Garry Hanan2
1
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
2
Département de Chimie, Université de Montréal, Montréal, Quebec, Canada
Interest in ruthenium polypyridyl complexes has been high since the discovery that ruthenium tris-bipyridine has a longlived, charge separated excited state. A large number of complexes have been synthesized over the intervening 30 years in an
attempt to understand the nature of this excited state and extend their usefulness. A complete series of compounds is reported
here, offering insights into the nature of complexes containing multiple metal centres and large planar aromatic ligands.
Electrochemical and electronic absorption data along with x-ray single crystal structures will be presented in this talk,
including the first trinuclear ruthenium polypyridyl complex crystal structure.
6+
N
N
N
N
Ru
N
N
Ru
N
N
N
N
Ru
N
N
N
N
N
N
N
N
10
K-13. Synthesis and Application in Catalysis of New Versatile Dendritic Architectures Built Using a Simple Divergent
Methodology
Olivier Bourrier and Ashok K. Kakkar.
Department of Chemistry, McGill University, Montreal, Quebec, Canada.
The synthesis of dendrimers involving 3,5-dihydroxybenzyl alcohol has been intensively studied using a convergent way.
However, using this monomer to do new dendritic architectures by following a divergent route is yet unexplored. We report,
herein, the construction of dimethylsilyl linked dihydroxybenzyl alcohol based dendrimers via acid-base hydrolytic chemistry
of bis(dimethylamino)dimethylsilane and 3,5-dihydroxybenzyl alcohol. The periphery of these dendrimers can easily be
functionalised with phosphorus donor groups that are subsequently bound to RhCl(1,5-C8H12). Such organometallic
dendrimers were found to be active and recoverable catalysts for hydrogenation of decene. Also uncontrolled and semi
controlled recactions of bis(dimethylamino)dimethylsilane and 3,5-dihydroxybenzyl alcohol led to the formation of
hyperbranched polymers polymers in which the build-up of the polymeric backbone was found to be controlled by the
preferential reactivity and sterics at the benzylic center.
K-14. Chemical Biology of Nitric Oxide and its Electrophilic Addition Products: New Access to ONNO Frameworks
Navamoney Arulsamy1, D. Scott Bohle2, and Jerome Imonigie1
1
Department of Chemistry, University of Wyoming, Laramie, Wyoming, USA
2
Department of Chemistry, McGill University, Montreal, Quebec, Canada
Sixteen years after the first demonstration of nitric oxide’s surprising role as a key vasodilator there remain many questions
about its ultimate fate in vivo. Although we now understand details of the chemistry and biology of its bulk reactions with
oxygen, superoxide, and oxyhemoglobin, NO’s reactions with metalloproteins and activated incipient nucleophilies remain
understood in outline only. In part this reflects the numerous gaps in our knowledge of the chemistry of this ostensibly
simple molecule. This presentation will focus on recent work concerning some of the products of nucleophilic addition to
NO, cases where two NO condense with the nucleophile to give diazeniumdiolates, RN(O)NO -, equation 1.
2 NO +
Nu
n
N
Nu
O
n
(1)
N
O
Nu = nucleophile
n = 0 or -1
Diazeniumdiolates are well established commercially available biomedical and analytical reagents whose known chemistry
includes simple alkylation, reversible protonation, coordination, and chelation. However all of these reactions are markedly
R dependent, and in some cases there is heterolysis and reversal of equation 1, to give two nitric oxides, or there can be an
umpolung in the R-N bond, with formal loss of R+ and the formation of cis-hyponitrite, -ONNO-. Finally, RN(O)NO- can
also undergo a Z/E interconversion corresponding to a formal rotation around the N=N bond, and the resulting E
stereoisomer isolated or trapped as a ring closed species. Recent examples of all of these reactivity patterns will be
presented, and contrasted with the known chemistry for the natural antibiotics alanosine and dopastin, both of which contain
the RN(O)NO- linkage.
OO
N
OH N
CH3
H
N O
HO
N
CH 3
NH
H2N
H
O
O
CH 3
Alanosine
Dopastin
11
M-1. Anion-dependent structures of noble-metal-complexes of blue-luminescent starburst ligands
Corey Seward, Emily Mitchell, Wenli Jia, and Suning Wang
Department of Chemistry, Queen’s University, Kingston, Ontario
Our interest in inorganic and organometallic complexes of blue-luminescent starburst ligands has stemmed from our efforts
to produce compounds useful in optoelectronic applications. The metal centre can enhance the luminescence, if it makes the
ligand more rigid in the final complex, leading to fewer thermal pathways for the dissipation of the energy of the excited
states. The addition of a metal centre also allows for the fine-tuning of structural and electronic properties, yielding more
flexibility in the design of a desired product. By changing the counter-ion or stoichiometry of a metal complex, for example,
we obtain products with vastly different topologies and properties. The extended structures of these compounds often lead to
significantly different interactions with solvents or other molecules, giving materials with potential uses as luminescent
sensors, or selective, photoactivated catalysts. Herein we will report our findings on Pt(II), Pd(II), Zn(II), Ag(I) and Au(I)
complexes of dipyridylamine-derivative starburst ligands 1,3,5-tris(di-2-pyridylamino)benzene, DAB, 2,4,6-tris(di-2pyridylamino)-1,3,5-triazene, DAT, 1,3,5-tris(di-(2-pyridylamino)-4-phenyl)benzene, DABT, and 2,4,6-tris(di-(2pyridylamino)-4-phenyl)-1,3,5-triazene, DAPT.
M-2. Photoswitching hydrogen-bonded azodibenzoic acid derivatives
Felaniaina Rakotondradany, Tony Whitehead, and Hanadi F. Sleiman.
Department of Chemistry, McGill University, Montreal, Quebec, Canada
Novel photoaddressable materials are needed for holographic and optical data storage. Photochromic systems like
azobenzene derivatives are useful for photoimaging, where light changes the structures of the chromophore and the matrix
embedding the chromophore. The photoisomerized chromophores then form a direct image. Azobenzene derivatives undergo
a reversible cis-trans isomerization upon photoirradiation. When exposed to UV-light, the trans isomer gives cis-azobenzene,
which reverts to the trans conformation by irradiation with visible light or by heating. Instead of using polymer matrices to
imprint optical information, the azobenzene is directly incorporated in a macromolecular system consolidated by hydrogenbonds. In this case, structural changes observed in individual monomers result in dramatic changes of the self-assembled
architectures. The light-induced isomerisation of azobenzene is thus amplified towards the formation of highly ordered
macromolecules by using hydrogen-bonding. The synthesis and structure of such a supramolecular system, for which 4,4'azodibenzoic dicarboxylic derivative forms photoswitchable hydrogen-bonded tapes and rosettes is described. Transazobenzene derivatives are irradiated to their cis isomers which self-associate into discrete hydrogen-bonded aggregates. The
light-induced conformational change occurs at the molecular level and propagates to the macromolecular level. UVirradiation triggers the trans-cis isomerization then the hydrogen-bonded self-assembly of discrete cyclic structures which
ultimately form nanorods through stacking interactions. Trans rodlike isomers form linear aggregates while cis photoisomers
yield squares. The different packing properties of these aggregates give divergent morphologies in the bulk.
12
M-3. Phase Transitions in the Superionic Pb1-xSnxF2 Solid Solution upon Ball-Milling
Georges Dénès , Matthieu Kernec, M. Cecilia Madamba and Marc Poizat
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
The PbF2 / SnF2 system is very rich in new materials. These include a wide Pb 1-xSnxF2 solid solution (0x0.50, cubic PbF2 fluorite-type for 0x0.30, tetragonal -PbSnF4 fluorite-type for 0.30<x0.50) and stoichiometric Pb2SnF6, PbSnF4 and
PbSn4F10. In addition, all the stoichiometric compounds undergo phase transitions on heating. These phases are also very
high performance fluoride-ion conductors, the best among all fluoride ion conductors, with PbSnF 4 being the very best. Ballmilling has been extensively used for oxides and other strong lattices, and it is usually found to lead slowly to amorphization.
Ball-milling has also been used to supply the energy required to perform solid state reactions. We investigated previously
the transformations taking place both in PbF2 and in PbSnF4, i.e. at both ends of the Pb1-xSnxF2 solid solution (at x = 0 and
0.50) when subjected to ball-milling. Both -PbF2 (orthorhombic, PbCl2 type) and -PbF2 (cubic, fluorite-type, x = 0) were
studied. They showed a strange behavior: in both cases, a partial transformation to the other allotrope was observed. In
addition, the two phases were nanocrystalline (highly broadened X-ray diffraction peaks). At the other end of the solid
solution, for -PbSnF4 (x = 0.50), ball-milling leads to an order/disorder transition, giving fully disordered nanocrystalline
µ-PbSnF4. This new phase of PbSnF4 is similar to non-quenchable -PbSnF4 observed above 390 oC, and has the fluoritetype structure. Surprisingly, the phase transition on ball-milling takes place very rapidly (ca. 5 minutes) and no
amorphization or further reduction of particle size occurs on further milling (checked up to 1 hour). In this work, the effect
of ball-milling on the Pb1-xSnxF2 solid solution has been investigated. It was interesting to see whether it would behave like
the materials -PbF2 or -PbSnF4 located at its boundaries, or whether it would have its own behavior. Not surprisingly, the
changes taking place vary with the composition of the solid solution. At small x values, a -PbF2 like behavior is observed,
while for the highest x values, it behaves like -PbSnF4 , with a slowing down of the transformation as x moves towards the
center of the solid solution, where no change is observed. The particle size obtained at a given ball-milling time is a function
of the fractional amount x of tin in the samples. The strange role of tin on the behavior when ball-milled will be discussed in
terms of tin bonding and coordination.
M-4. Modern Semiempirical SCF MO Methods in Inorganic Chemistry
S. I. Gorelsky1, 2, and A. B. P. Lever2
1
Department of Chemistry, Stanford University, Stanford, California, U.S.A.
2
Department of Chemistry, York University, Toronto, Ontario, Canada
In the last 30 years semiempirical MO methods were able to provide significant insight into chemical problems which were
too large for study using more sophisticated methods. In the recent years, fast personal computers and user-friendly software
for computational quantum chemistry created an opportunity to run semiempirical SCF MO calculations in every chemical
laboratory. Chemistry continues to grow, chemical structures under investigation become bigger and bigger. Studies of large
molecular systems, such as bioinorganic systems, are currently out of reach of high-level ab initio methods. On the other
hand, modern semiempirical SCF MO methods are becoming more reliable and accurate and can handle molecules with
hundreds of atoms.
Modern semiempirical SCF MO methods (INDO/1, INDO/S, CINDO-E/S, MINDO/SR,
MSINDO, MNDO/d, AM1/d, PM3(tm), PM3d, PM5, NDDO/MC, SAM1, OM1, OM2, etc.) are described and discussed.
Structural, thermochemical and spectroscopical applications for inorganic species are presented.
13
M-5. Metal-Metal Coupling in Asymmetric Dinuclear Mixed-Valence Ruthenium Complexes
Joseph Kahenya and Robert.J.Crutchley*
Ottawa-Carleton Chemistry Institute, Department of Chemistry, Carleton University, Ottawa, Ontario, Canada
Electronic and magnetic properties of asymmetric dinuclear ruthenium complexes bridged by 1,4-dicynamidobenzene
dianion(dicyd2-) are investigated through the systematic application of outer-sphere perturbations. The results are interpreted
in terms of superexchange coupling between the metal d orbitals as mediated by the bridging ligand HOMO.
M-6. Anticeramic Yield: Ceramic Precursors in Polymer-Assisted Vapour Deposition versus Classical Polymeric
Route
Sanela Martic*, Nathalie Camire**, Eric Gagnon*, Abdelatif Jaouad**, Cetin Aktik** and Mihai Scarlete*
* Bishop's University, Lennoxville, Quebec, Canada, **Universite de Sherbrooke, Sherbrooke, Quebec, Canada
We will present a new theoretical concept resulting from our efforts of modeling the complex chemical reaction cycles
associated with the synthesis of semiconductor thin films via Polymer-Assisted Chemical Vapor Deposition1 (PA-CVD). PACVD is a new procedure for the synthesis of thin films from polymeric precursors. This process, unlike the classical
polymeric route, emulates CVD-like methods, and allows the synthesis of ceramic thin films with superior textural properties
and of electronic-grade purity. For example, the impurity level achieved during the synthesis of semiconductor silicon
carbide thin films was in the range of 1014-1015 donors/cm3, rendering these films useful for electronic application. Due to the
specificity of the process to induce oscillatory behaviour in the system under certain synthesis conditions, the possible
applications can be expanded to include a combinatorial approach to the design of electronic devices. The PA-CVD method
involves the thermal fragmentation of a polymer, followed by the desublimation of the gaseous species produced onto cold
substrates under a temperature-gradient field. The in situ polymeric fragments produced during PA-CVD, form a new class of
gaseous precursors from polymeric sources. The generation of the gaseous precursors produced from poly(organo)silanes in
PA-CVD has been correlated to the atmosphere of the pyrolysis in the case of the poly(dimethylsilane) precursor pyrolyzed
under partial pressure of ammonia during the synthesis of semiconductor silicon carbide thin films. The generation of
gaseous species is a function of the proportion of a transamination reaction that can occur during the pyrolysis. This reaction
was linked to the dramatically decreased "ceramic yield" observed in PA-CVD. The gaseous PA-CVD precursors have been
studied via the rotational fine structure of the vibration bands. The ratio between the weight of all gaseous species generated
in PA-CVD versus the mass of the source-polymer led to the creation of the new theoretic concept of "anticeramic yield".
The rotovibrational spectra of the gases indicate methane, ethylene, silane, but also higher molecular mass species such as
methylsilane, dimethylsilane and other polymer fragments acting as gaseous precursors for the formation of the amorphous
silicon carbide thin films deposited on various substrates. The incorporation of Nitrogen-dopant is the result of preferential
ternary N-based crosslinking sites in large molecular mass species with higher desublimation probability. These species are
obtained during the transamination reaction simultaneously together with low molecular weight aminosilane species that may
be responsible for the increased "anticeramic yield" observed in PA-CVD. Molecular modeling and computational programs
have been used to correlate spectroscopic results to the proposed model for the chemical cycles in PA-CVD. A proposal for
the main chain of reactions involved in the PACVD process has been outlined and correlated to the resistivity of the
synthesized films deduced from C(V) characteristic obtained via Hall-effect measurements.
14
1
Scarlete, M. and Aktik, C. (2002). International provisional patent, submitted May 13
M-7. Tuning the Luminescence and Electroluminescence of Diphenylboron Complexes of Substituted 2-(2'Pyridyl)indoles
Qinde Liu1, Maria S. Mudadu2, Randolph Thummel2, Ye Tao3, and Suning Wang1
1
Department of Chemistry, Queen’s University, Kingston, Ontario, K7L 3N6, Canada
2
Department of Chemistry, University of Houston, Houston, Texas 77204-5003, USA
3
Institute for Microstructural Sciences, National Research Council, 100 Sussex Drive, Ottawa, K1A 0R6, Canada
To examine the effect of substituent groups on the luminescence of BPh 2(X-2-PI) complexes (X-2-PI = 5-substituted-2-(2’pyridyl)indoles, three new air stable boron complexes BPh2(F-2-PI) (1), BPh2(Cl-2-PI) (2) and BPh2(CH3O-2-PI) (3) were
synthesized and characterized, where F-2-PI = 5-fluoro-2-(2’-pyridyl)indole, Cl-2-PI = 5-chloro-2-(2’-pyridyl)indole and
CH3O-2-PI = 5-methoxyl-2-(2’-pyridyl)indole. In these complexes, the 5-substituted 2-PI ligand chelates in a tretrahedral
fashion to the boron center. Compounds 1-3 are luminescent with 1 having the highest emission efficiency. Compared with
the emission maximum of BPh2(2-PI) (516 nm), the emission maximum of 1 and 2 is blue-shifted to 490 nm and 487 nm,
respectively, while the emission of 3 is red-shifted to 532 nm, indicating the possibility of tuning the luminescence of these
complexes by varying the substituent groups on the 2-PI ligand. An electroluminescent device using compound 1 as the
emitter and the electron transport material has been fabricated. In order to investigate further the effect of more substituent
groups on the luminescence of BPh(X-2-PI) complexes, boron complexes of difluoro and trifluoro substituted 2-(2’pyridyl)indoles were also synthesized, and their luminescent properties were investigated. The results show that more fluoro
substituent can tune the luminescent more blue. Therefore, a facile route towards stable blue luminescent boron compounds
could be developed.
M-8. Scavenging with TEMPO• to Identify Peptide- and Protein-based Radicals by Mass Spectrometry: Advantages
of Spin Scavenging over Spin Trapping
P. John Wright and Ann M. English*
Department of Chemistry and Biochemistry, Concordia University, 1455 de Maisonneuve Blvd W.t, Montreal, QC, Canada
The detection and characterization of radicals in biomolecules is difficult due to their high reactivity and low concentration.
Mass spectrometry (MS) provides a tool for the unambiguous identification of protein-based radicals by exploiting their
reactivity with suitable reagents.1,2 To date, protein-radical detection by MS has been modeled after electron paramagnetic
resonance experiments, in which diamagnetic spin traps convert unstable radicals to more stable spin adducts. Since MS
detects mass changes, and not unpaired spins, conversion of radicals to stable diamagnetic products is desirable. The use of
2,2,6,6-tetramethylpiperidinyl-1-oxy (TEMPO•) in the MS identification of protein-based radicals was explored here to
establish whether scavenging via radical combination would give rise to TEMPO-adducts that were stable to MS analysis.
The horseradish peroxidase (HRP)/H2O2 reaction was used for radical generation in derivatives of tyrosine, tryptophan and
phenylalanine as models of peptide-based radicals. TEMPO• was added as a radical scavenger and the products analyzed by
ESI-MS. Dramatic increases in mass-adduct yields and hence sensitivity were obtained using radical scavenging vs radical
trapping. The efficiency of TEMPO• in protein radical scavenging was examined in horse heart myoglobin and cytochrome
c peroxidase (CCP) from Saccharomyces cerevisiae. Following H2O2 binding to the ferric heme, two oxidizing equivalents
are transferred to the proteins as an Fe IV=O species and a polypeptide-based radical. In addition, CCP has been shown to
reduce up to 20 equivalents of H2O2 using endogenous donors, thereby generating as many as 20 radicals on its polypeptide.
Following myoglobin and CCP incubation with a 10-molar excess of H2O2 and TEMPO , MALDI-ToF analysis of the
tryptic peptides derived from the proteins revealed 1 and 9 TEMPO-adducts of myoglobin and CCP, respectively. Given the
high scavenging efficiency of TEMPO and the stability of TEMPO-labeled peptides in ESI and MALDI-ToF mass
spectrometers, use of stable nitroxide radicals coupled with MS analyses should provide sensitive and powerful technology
for the characterization of protein-based radicals. Spin scavenging is also expected to be more selective over spin trapping
given the high reactivity of stable nitroxides with carbon-centered radicals. Furthermore the well-documented properties of
15
the caboxylamine bond can be exploited in confirming spin scavenging. Mechanisms of protein radical translocation and of
their roles in redox signaling will hopefully be elucidated by the technology described here.
M-9. Synthesis and Characterization of Phosphido-Coated Gold Nanoclusters
Diana M. Stefanescu, and David S. Glueck*
Department of Chemistry, Dartmouth College, Hanover, NH, USA
Gold nanoparticles have been widely investigated recently especially as building blocks for electronic devices. For this
purpose the most studied systems were the thiolate and the tertiary phosphine coated gold clusters. The small core size and
narrow size distribution obtained especially in the latter case suggested that we attempt the synthesis of phosphido coated
gold clusters starting with secondary and primary phosphines. Phosphido-protected gold nanoclusters Aux(PR2)y were
synthesized in a single phase (THF/water) from a Au(III) salt, a phosphine and NaBH 4 as reducing agent. Both reaction and
work-up were done under inert atmosphere. TEM data shows that their average core diameter is 1-2 nm with a size
distribution of 30%. Bulkier phosphines are preferred both because the solubility of the gold clusters is increased and the gold
polymer ( [AuPR2]n) obtained as impurity is formed only in small amounts.
M-10. Optical Properties of Er3+-Doped Nanocrystalline Gd2O3
Fiorenzo Vetrone1, John-Christopher Boyer1, John A. Capobianco1, Adolfo Speghini2 and Marco Bettinelli2
1
Department of Chemistry and Biochemistry, Concordia University, 1455 de Maisonneuve Blvd. W., Montreal, Quebec,
Canada, H3G 1M8
2
Dipartimento Scientifico e Tecnologico, Università di Verona, and INSTM, UdR Verona, Ca' Vignal, Strada Le Grazie 15, I37134 Verona, Italy
As many of today’s technologies are being reduced in size, the focus of optical materials research has shifted towards finding
phosphors that have increased luminescence efficiency but much smaller size. In this regard, lanthanide doped
nanocrystalline materials are believed to be key in the development of novel opto-electronic devices with reduced
dimensions. Oxides, in particular sesquioxides, have received considerable attention due to their ease of synthesis at the
nanoscale level and favorable physical properties. While yttrium oxide (Y 2O3) and lutetium oxide (Lu2O3) have been the
subject of intense research, gadolinium oxide (Gd 2O3) has for the most part been largely overlooked. The erbium ion is an
excellent candidate for doping due to its blue, green, red and NIR Stokes emissions. Furthermore, it possesses electronic
energy levels in the NIR, which act as population reservoirs giving it the capability to produce intense anti-Stokes blue, green
and red emissions. From a spectroscopic point of view, nanocrystalline Gd 2O3:Er3+ is fundamentally different from
Y2O3:Er3+ or Lu2O3:Er3+. The yttrium and lutetium oxides crystallize with a cubic structure and posses two distinct sites
available for lanthanide ion substitution, one with point group symmetry C 2 and the other with C3i symmetry. In contrast,
gadolinium oxide has a monoclinic structure in which the lanthanide ions are located in three non-equivalent Cs symmetry
sites resulting in vastly different optical spectra. In this paper, we study the optical properties of monoclinic gadolinium oxide
(Gd2O3) nanocrystals doped with 0.1, 1, and 10 mol% Er 3+.
16
M-11. The Synthesis, Characterization, and Bioconjugation of Tc/Re Metallocarboranes
O.O. Sogbein, P.Morel, and J.F. Valliant
Department of Chemistry, McMaster University, Hamilton, Ontario, Canada
Radiopharmaceuticals are routinely used in nuclear medicine departments for diagnostic or therapeutic applications. 99mTc
(t1/2 = 6.02 hrs) is the most widely used radionuclide in diagnostic medicine, accounting for approximately 85% of diagnostic
scans performed in nuclear medicine departments. Most 99mTc radiopharmaceuticals are based on Tc(V) oxo or octahedral
Tc(III) cores. More recently, there is interest in preparing imaging agents using Tc(I). Alberto and co-workers have
developed a method for the preparation of Tc(I) and Re(I) tricarbonyl complexes possessing a fac-M(CO)3 (M = Tc, Re) core.
These precursors, which can be prepared in water offer the opportunity to synthesize organometallic radiopharmaceuticals
including CpM(CO)3. Our work focuses on the use of carboranes, in particular, the dicarbollide dianion, as a ligand for the
preparation of Tc/Re radiopharmaceuticals. The dicarbollide dianion is isolobal with the cyclopentadienyl ligand and can
form low valent Tc(I)/Re(I) metallocarboranes. The advantages of carboranes as potential ligands are their stability, ease of
functionalization, and that they can be prepared in aqueous media. We have successfully prepared a series of bifunctional
Tc/Re metallocarboranes possessing a range of different functionalities. These functionalities are used to conjugate
complexes to various biomolecules including peptides. The synthesis, characterization, and bioconjugation of Tc/Re
metallocarboranes will be presented.
M-12. Kinetics and Mechanisms of Abiotic Methylation of Aqueous Mercury
Valbona Celo and Susannah Scott
Department of Chemistry, University of Ottawa, Ottawa, Canada
Mercury is found in aquatic ecosystems mainly as dissolved Hg 0, inorganic Hg(II) and MeHgX, the latter being the most
toxic form. The formation of methylmercury is widely believed to be a biological process, mediated by bacteria such as the
sulfate-reducers. However the distribution and activity of these bacteria is not sufficient to account for the rate of methylation
reported for some aquatic environments. This observation has led some researchers to propose that abiotic processes may
also be important. We have investigated the rates of reaction of inorganic Hg with some organic and inorganic methylating
agents present in natural waters: methyl iodide, methyltin compounds Me nSnCl4-n, methylcobalamin and methylcobaloxime,
MeCo(dmg)2(H2O). The mechanisms of these reactions and their yields of methylmercury are quite different and depend on
several environmental factors such as temperature, pH and salinity. Our results suggest that abiotic methylation is feasible
under particular conditions in some aquatic environments.
17
M-13. S-Nitrosation of Recombinant Calbindin D28K From Human Brain Mediated by Cu,Zn Superoxide Dismutase
Limei Tao and Ann English*
Department of Chemistry and Biochemistry, Concordia University, 1455, de Maisonneuve Blvd. W., Montreal, Quebec, H3G
1M8
Calbindin D28K (CaBP), a Ca2+-binding protein, is noted for its abundance and specific distribution in mammalian brain and
sensory neurons. CaBP has been found coexistent with hypothalamic nitric oxide synthase by immunostaining, suggesting
possible interactions between nitric oxide (NO) and calcium signaling. Using a variety of biophysical techniques, including
mass spectrometry, we have show that CaBP can be readily S-nitrosated by S-nitrosoglutathione. Since up to 4 cysteine
residues are S-nitrosated, we propose that CaBP acts as an NO buffer in the brain in a manner similar to serum albumin in
blood. Our studies further indicate that the presence of redox-active copper promotes S-nitrosation of CaBP, and that copperzinc superoxide dismutase (SOD) is a likely catalyst in vivo. Since CaBP, NO and SOD are implicated in neurodegenerative
diseases such as Parkinson’s and Huntington’s diseases, a full understanding of how these species may interact in vitro and in
vivo is crucial.
M-14. The Doubly Disordered Ba1-xSnxCl1+yF1-y Solid Solution: The First Example of a Mixture of Sn2+ Stannous Ions
and Covalently Bonded tin(II) in the Same Material
Georges Dénès and Abdualhafeed Muntasar
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
Divalent tin is found covalently bonded in all fluorides and chlorides, except Sn(SbF 6)2 and SnCl2. On the other hand, the
Sn2+ stannous ion is commonly observed only with large and lower electronegativity chalcogens (Te) and halogens (I). In
this work, a wide Ba1-xSnxCl1+yF1-y solid solution has been prepared by two methods: (i) precipitation of Ba1-xSnxCl1+yF1-y(aq)
when aqueous solutions of BaCl2 and SnF2 are mixed at a high BaCl2 content, and (ii) dry synthesis of Ba1-xSnxCl1+yF1-y(ssr)
(0≤x≤0.25, -0.15≤y≤0.25) by direct reaction of appropriate amounts of BaCl 2, BaF2 and SnF2 at high temperature, under inert
conditions. Both methods of preparation give a material that has the X-ray diffraction pattern of BaClF, which is a tetragonal
distortion of fluorite-type BaF2, with layers of fluoride ions and corrugated sheets of chloride ions parallel to (a,b) alternating
along the c axis. The absence of superstructure or lattice distortion shows that Ba and Sn are fully disordered, and that y Cl
are disordered with (1-y)F on the F lattice when y>0, and -y F and (1+y)Cl are disordered on the Cl lattice for y<0. Tin-119
Mössbauer spectroscopy shows that all the tin(II) is ionic (Sn2+) in
Ba1-xSnxCl1+yF1-y(aq), whereas Ba1-xSnxCl1+yF12+
ions and covalently bonded tin, the relative amount of which changes with the x and y
y(ssr) contains a mixture of Sn
compositional parameters. The amount of covalently bonded tin(II) increases with increasing tin content x, and with
increasing fluorine content (more negative y), whereas Sn2+ ions are favored in the solid solution dilute in tin (low x) and rich
in chlorine (high positive y). Covalently bonded tin is likely favored by the formation of Sn-F-Sn bridges in tin clusters, with
a SnF4E (E= lone pair) square pyramid, whereby the lone pair is in the apical position and the tin-lone pair axis is parallel to
the c axis of the unit-cell. When the fractional tin content x increases and the fractional amount y of chlorine replacing
fluorine increases, considerable softening of the Sn2+ sublattice is observed, making the ion rattle in its oversized anionic box,
due the replacement of some F by bulkier Cl. Rattling is frozen at cryogenic temperatures. The Ba 1-xSnxCl1+yF1-y solid
solution shows several features never observed before.
18
ABSTRACTS OF POSTER PRESENTATIONS
P-1. Synthesis and Characterization of Pt(II) Complexes of The Types Pt(R2SO)(pyrazine)Cl2 and
Pt(R2SO)Cl2(pyrazine)Pt(R2SO)Cl2
Fernande D. Rochon and Julien R. L. Priqueler
Département de Chimie, Université du Québec à Montréal, Montréal, Québec, Canada.
Two new types of pyrazine platinum(II) complexes, Pt(R2SO)(pz)Cl2 and Pt(R2SO)Cl22(-pz) (pz = pyrazine) have been
synthesized and characterized by infrared and multinuclear magnetic spectroscopies ( 195Pt, 1H and 13C) and by
crystallographic methods. The 195Pt NMR resonances of the pyrazine-bridged complexes were observed at about the same
field as the monomeric analogues. The 3J(195Pt-1H) coupling constants of the pyrazine protons of the dimers are between 28
and 35 Hz, suggesting a trans geometry. The crystal structures of one cis (dipropylsulfoxide) and one trans
(tetramethylenesulfoxide) monomeric compounds and of three pyrazine-bridged dimeric complexes (dipropylsulfoxide,
tetramethylenesulfoxide and dibutylsulfoxide) were determined. The latters have the trans geometry.
P-2. Functionalized Carboranes as Radiopharmaceutical Synthons
Andrew Green1, Raymond Chankalal1, Pierre Morel1, Paul Schaffer1, Oyebola O. Sogbein1, John F. Valliant1,2
1
Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, Ontario
2
Department of Chemistry and The Medical Physics & Applied Radiation Sciences Unit, McMaster University, 1280 Main
Street West, Hamilton, Ontario
Bioorganometallic chemistry is an emerging field of research that involves the coordination of bioactive or radioactive metals
to biologically relevant ligands through at least one metal – carbon bond. One of the challenges in this field is the ability to
prepare stable organometallic complexes in aqueous media. Our group recently reported a new method for the
5
synthesis of Tc/Re -ligands1. These compounds are
ideal synthons for the preparation of targeted radiopharmaceuticals. The dicarbollide dianion (2), which unlike most
organometallic ligands, is stable in water and readily reacts with [M(CO) 3Br3]2- (M = Re, Tc) to form compound (3) in
excellent yield. Our current focus, which is the subject of this presentation, is the synthesis of bioconjugates of (3). To this
end, we have prepared a series of carbohydrate and arene-carborane derivatives as a way of targeting diagnostic and
therapeutic radionuclides to tumours.
1CO
1-
C
(1)
= BH
C
R
CO
OC
H
H
NaOH
C
Ethanol, Reflux
(2)
C
H
R
M
Na2CO3
C
[M(CO)3Br3]2-
C
(3)
M = Re, Tc
H
R
19
P-3. A Facile Palladium Catalyzed Three Component Coupling Route to Imidazoles
Ali R. Siamaki, Rajiv Dhawan, and Bruce A. Arndtsen*
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada.
Imidazoles represent the core structure of a range of important therapeutics, including antitumor and anti-inflammatory
agents. While there are a number of synthetic routes to imidazoles, these typically involve multistepsyntheses,which limit the
diversity of these compounds readily available. We have been investigating an alternative palladium catalyzed synthesis of
tetrasubstituted imidazoles. This process involves the formation of 1,3-oxazolium-5-oxide (Münchnone) intermediates, via
palladiumcatalyzed coupling of imines, acid chlorides and carbon monoxide. The Münchnone intermediate can undergo 1,3dipolar cycloaddition with N-tosylimines to provide an overall one-pot synthesis of imidazoles. This catalytic synthesis
can be generalized to a range of imidazoles via simple variation of imine or acid chloride building blocks. The scope and
mechanism of this reaction will be discussed.
P-4. Optical and Upconversion Properties of a Ho 3+ Doped ZnO-TeO2 Glass
John-Christopher Boyer1, Fiorenzo Vetrone1, John A. Capobianco1, Adolfo Speghini2 and Marco Bettinelli2
1
Department of Chemistry and Biochemistry, Concordia University, 1455 de Maisonneuve Blvd. W., Montreal, Quebec,
Canada, H3G 1M8
2
Dipartimento Scientifico e Tecnologico, Università di Verona, and INSTM, UdR Verona, Ca' Vignal, Strada Le Grazie 15, I37134 Verona, Italy
Tellurite based glasses of various compositions doped with rare-earth ions have generate much interest recently not only as
possible optical amplifiers but also as a possible host for solid-state lasers. Tellurite glasses possess one of the lowest phonon
energies of the oxide glasses. Combine this with a high refractive index that not only facilitates waveguiding but also
benefits radiative transitions of RE ions and one has a attractive host for a tunable upconversion laser. Recently, there has
been a significant amount of interest in Ho 3+ doped crystals and glasses as upconversion materials, with several groups
demonstrating continuous wave (cw) green upconversion lasing from Ho 3+ doped glass fibers pumped with red light. In this
study we examine the optical and upconversion properties of a 19ZnO-80TeO2-1Ho2O3 glass. After excitation with 457.9 nm
radiation at room temperature (RT) and 78 K, the glass exhibits four distinct emission bands in the visible and near-infrared
portions of the spectra corresponding to the 5F3  5I8 (480-500 nm), (5F5, 5S2)  5I8 (480-500 nm), 5F5  5I8 (630-680 nm)
and (5F5, 5S2)  5I7 (735-775 nm) transitions. Blue and yellow-green anti-Stokes emission corresponding to the 5F3  5I8 and
(5F4, 5S2)  5I8 transitions respectively was observed after excitation with 646 nm radiation at RT from a dye laser that
excites the 5F5 level. To determine the number of photons involved in the upconversion process the intensity of the
upconverted blue and green emission was measured as a function of the 646 nm excitation intensity. The upconverted
luminescence exhibited a quadratic dependence on the pump power indicating a two-photon upconversion process. The
upconversion luminescence is thought to occur through an excited state absorption (ESA) upconversion process. Upon
excitation with 754nm radiation from a Titanium Sapphire laser that excites the 5I4 level, anti-Stokes emission corresponding
to the 5F3  5I8; (5F4, 5S2)  5I8; and 5F5  5I8 transitions were observed. The (5F4, 5S2)  5I8 transition demonstrated a
quadratic dependence on the power of the pump beam indicating that two photons were involved in the excitation process.
Again an excited state absorption (ESA) process is thought to be the dominant mechanism. Mechanisms for the two
upconversion processes are also proposed.
P-5. Low-Coo
-Diketiminate Ligands
Nathan A. Eckert, Emily M. Bones, Rene J. Lachicotte and Patrick L. Holland
Department of Chemistry, University of Rochester, Rochester, NY, USA.
Late-transition metal amido compounds are involved in several catalytic processes, including the hydroamination of
multiple bonded hydrocarbons. They may also be precursors for more reactive transition metal imido complexes, which are
frequently invoked as intermediates in catalytic processes such as azirdination. Imido complexes are isoelectronic analogues
of terminal oxo compounds, which are thought to be intermediates in the catalytic cycle of several iron-containing enzymes
that perform several O2- or H2O2-initiated oxidation reactions. In our attempts to model these catalytically active species we
-diketiminate ligands.
The synthesis, structure and spectroscopy of several Fe(II) and Fe(III) amido compounds is presented, along with initial
20
reactivity studies.
In order to create three-coordinate nickel(II) amido complexes, suitable nickel(II) chloride starting
-diketiminates and nickel salts. These display interesting solvent-dependent equilibria that
were explained using 1H NMR and UV/vis data. These could be converted into a three-coordinate nickel(II) amido complex.
P-6. New Hydride Complexes of Ruthenium and Iridium Bearing N-Heterocyclic Carbene Ligands
Robert H. Morris, Kamaluddin Abdur-Rashid, Terry Fedorkiw, Alan Lough, Leonie Soltay
Department of Chemistry, University of Toronto, Toronto, Ontario, Canada
Synthetic and spectroscopic considerations of RuH(IMes)(PPh3)2, IMes = 1,3-Bis(2,4,6-trimethylphenyl)imidazol-2-ylidene
RuH2(ItBu)(PPh3)2, ItBu = 1,3-Di-tert-butylimidazol-2-ylidene, and IrH5(IMes)(PiPr3)2 are presented. The complex
RuH(IMes)(PPh3)2 shows interesting C-H bond activation through cyclometallation with the IMes ligand. The NMR of
RuH2(ItBu)(PPh3)2 shows fluxionality through an agostic interaction with the I tBu ligand, confirmed by variable temperature
studies. IrH5(IMes)(PiPr3)2 is the first example of a transition metal polyhydride carbene complex.
P-7. Development of Analogues of Titanocene Dichloride as Potential Anti-tumor Agents
Patrick W. Causey1, Michael C. Baird1, Kathy Sparks2, and Susan P.C. Cole2
1
Department of Chemistry, Queen’s University, Kingston, Ontario
2
Cancer Research Laboratories, Queen’s University, Kingston, Ontario
Following the remarkable success of cisplatin for the treatment of various cancers, research, in the early 1980’s, into the
potential use of transition metal-based organometallic compounds revealed the chemotherapeutic activity by group IV
metallocene dihalides (MIVCp2X2; M=Ti, Zr, and Hf). Due to the lowered toxicity and the effectiveness against cisplatinresistant tumor cells, clinical and pre-clinical trials with titanocene dichloride have demonstrated a novel and potentially
useful mode of activity. Our research has focused on two major goals with regards to generating analogues of titanocene
dichloride. The first is to design, synthesize and characterize a collection of novel and known analogues. Predominantly, the
analogues have been generated through substitution onto the cyclopentadienyl ring. Functional group substitutions have been
made to include both steric and electronic factors. Following the successful synthesis of these compounds, each would be
tested in vitro for antitumor activity against a small cell lung cancer cell line, A549. The second goal of the project has been
to investigate the pharmacokinetics of the general family of titanium-based compounds. It is generally accepted that
biodistribution is related to coordination to the ubiquitous protein, transferrin. Therefore, coordination of the titanocene
analogues with a protein mimic, ethylene(hydroxyphenyl)glycine, would be examined. Recent results will be presented.
21
P-8. Synthesis, Characterization and Reactivities of Complexes of the Ttype bis- and tris(3,5-dimethylpyrazol-1yl)methane-nickel
Annie Michaud and Davit Zargarian
Département de Chimie, Université de Montréal, Montréal, Québec, Canada.
This presentation will elaborate on the synthesis and characterization of some Ni(II)
bis- and tris(pyrazolyl)methane complexes. These halogenated compounds display
very diverse and interesting spectroscopic properties and structural features.
Alkylation of some precursors seems to form thermally Ni-alkyl unstable products;
the spectroscopic and reactivities of these in-situ prepared species will be presented.
The reduction of Ni(acac)2 with alkylaluminium complexes failed to furnish Ni(0)
poly(pyrazolyl)methane compounds. Instead, we were able to isolate and structurally
characterize some unusual intermediates or byproducts, these results will be presented.
N
N
N
+
Ni
X
N
P-9. Preparation and Reactivities of Indenyl Palladium Complexes
Christine SUI-SENG *, Daniel GAREAU, Laurent F.GROUX, Davit ZARGARIAN
Département de chimie, Université de Montréal
This presentation will describe our preliminary results in a project which involves a study of the reactivities of indenyl
complexes of group 10 metals. The long term objective of our work is to develop the catalytic reactivities of these complexes
in a number of reactions, including oligomerization and polymerization of silanes, alkenes and alkynes, coupling reactions,
nucleophilic reactions, etc. The complexes (R-Ind)Pd(PR’3)Cl (R = Me, i-Pr, SiMe3; R’ = Ph, Cy, Me) an be prepared by
displacement of the PhCN ligand in (R-Ind)Pd(PhCN)Cl; the latter are, in turn prepared from R-IndLi and PdCl2(PhCN)2.
The conversion of these complexes to the corresponding neutral palladium alkyl complexes or bis(phosphine) cations have
been studied. The preliminary catalytic properties of the latter complexes will be discussed. We will also present the results
of our studies with Ni and Pd complexes bearing the ligand (CH 2=CH-CH2-SiMe2)-Ind, wherein the goal is to coordinate the
tethered olefin moiety to the metal center.
R
Pd
R'3P
Cl
R = Me, i-Pr, SiMe3
R' = Ph, Cy, Me
22
P-10. 3,4-Dimethyl-1,1-Diphenyl-2,5-Dihydro-1H-Germole,
Diphenylgermylene
the
First
Clean
Photochemical
Source
of
Cameron R. Harrington and William J. Leigh.
Department of Chemistry, McMaster University, 1280 Main Street West, Hamilton, ON Canada, L8S 4M1
The reactions of germylenes, the heavier congeners of carbenes and silylenes, have been extensively studied for the past
quarter century. A very limited body of literature suggests that germylene reaction mechanisms (with a few notable
exceptions) are closely related to those of silylenes. Both species are usually sufficiently reactive to necessitate the use of
time-resolved spectroscopy, employing photochemical precursors, in order to follow their reaction kinetics. However, the
photochemistry is often complex and much of the data in the literature is consequently subject to various interpretations and
mechanistic conclusions.
EtOH
Ph2Ge OEt
H
h
Ph2Ge
1
+
[Ph2Ge:]
x2
2
[Ph2Ge=GePh2]
3
Ph2Ge
Steady state and laser flash photolysis studies of the photochemistry of 3,4-dimethyl-1,1-diphenyl-2,5-dihydro-1Hgermole (1) demonstrate this compound to be a clean, high yielding source of diphenylgermylene (Ph 2Ge:) (2), the
germanium analogue of diphenylcarbene. In the absence of added chemical traps this species (λ max = 500 nm) decays on the
microsecond time scale with second order kinetics in hexane solution to yield a transient (λ max = 440 nm) that has been
identified as tetraphenyldigermene (Ph2Ge=GePh2) (3). Absolute rate constants for reaction of both the germylene and
digermene with several characteristic trapping reagents have been determined, and the reaction products characterized in
steady state experiments.
P-11. Nonlinear Optical Chromophores with Heavy Main Group Elements
A.F. Cozzolino, J.C. Landry, W. Zhang and I.Vargas-Baca
McMaster University, Department of Chemistry, 1280 Main St. West, Hamilton ON, L8S 4M1.
Currently there is great interest in the development of molecules with large hyperpolarisabilities for applications in nonlinear
optical (NLO) materials. Large hyperpolarisabilities can be achieved by placing donor and acceptor groups at opposite ends
of π systems, these are often referred to as D-π-A chromophores. The heavy elements of the p-block posses the largest atomic
hyperpolarisabilities, however there are very few reports of NLO chromophores that take advantage of this property.
Amongst the main-group elements, the chalcogens (S, Se, Te) are the best suited to participate in organic chromophores. In
some cases the heavy element has been included as part of a heterocycle, but the synthesis of such molecules is often
laborious. Grafting the chalcogen onto a molecule with a single bond is a simpler operation and, if the chromophore contains
accessible double bonded N or O atoms, intramolecular coordination will ensure delocalisation of chalcogen electrons into
the chromophore. Existing NLO chromophores can be conveniently modified to contain chalcogen atoms through
orthometallation and metathesis (see scheme below)1. We will discuss our strategy for both the mercuration of asymmetric
azobenzenes and the preparation of their chalcogen derivatives. The initial products of this reaction were obtained in low
yields, partly due to the low solubility of the starting material and the product. The synthesis of a more soluble starting
material helped to facilitate this reaction. In addition to this synthetic research, a complementary computational study has
been undertaken. Calculated values of hyperpolarisabilities and their orientational averages 2 have been completed using the
ZINDO formalism. These values were obtained in order to compare with the orientationally-averaged values obtained from
the HRS experiment for above chromophores.
23
Cl
D
Hg
MCl
N
N
A + HgR2
D
-MR
1) R'Li
N
N
A
2) Cl
E
D
E R''
R"
N
N
A
E = S, Se
1. Landry, J.C. B.Sc. Thesis, McMaster University, Hamilton 2002
2. Brasselet S. and Zyss J., J. Nonlinear Optical Phys. And Mat. 1996, 671-693
P-12. Facile synthesis of tridentate ligands for room temperature luminescence in ruthenium complexes
M.I.J. Polson,Elaine A. Medlycott, Larissa Mikelsons, Andrea Martins, N. Taylor and G.S. Hanan,
Département de Chimie, Université de Montréal, Montréal, Québec.
Department of Chemistry, University of Waterloo, Waterloo, Ontario.
The intense research into the photophysical properties of ruthenium tris-bipyridine complexes stems from the long lifetime of
the charge seperated MLCT excited state. Achiral tridentate ligands, like terpyridine, are generally more useful in the
synthesis of multinuclear systems as the production of complicated isomers can be avoided. However, ruthenium bisN
N
(PF6)2
N
N
N
N
Ru
N
N
N
terpyridine complexes have short excited state lifetimes due to the rapid non-radiative relaxation of the MLCT state through a
low-lying dd state. Here we report a new series of ligands which is rapidly synthesised from simple starting materials and that
exhibits strong room temperature luminescence in their ruthenium complexes.
P-13. Oxo-Rhenium(V) Complexes with 8-Hydroxyquinoline Derivatives
Olivier Sigouin, Marc Palardy and André L. Beauchamp
Département de Chimie, Université de Montréal, Montréal, Québec, Canada
Small monomeric systems exhibiting electron-spin transitions are actively sought for eventual applications in energy storage
and other molecular devices. Oxo-rhenium(V) species provide promising low-spin d2 metal centres and earlier studies have
shown that the energy gap between the HOMO (d xy) and the LUMO (dxz/dyz) orbitals is relatively small in certain complexes
containing an axial O=Re-X(OR) core. Since these are -type metal orbitals, we looked for a simple tunable ligand with a
controlled -orbital system that could provide information on the influence of -interactions on the energy gap. The ligand
first selected is 8system with
respect to the equatorial plane.
24
O
Cl
O
Cl
Re
Ph3P
Cl
O
O
N
N
Re
N
N
N
O
O
O-
The ReOCl2(PPh3)(L) and ReOCl(L)2 series of complexes were obtained for L = oxine and its 2-methyl, 5-chloro, 5-nitro,
5,7-dichloro, 5,7-dibromo and 5,7-diiodo derivatives. They were characterized by microanalysis, infrared, and 1H and 31P
NMR spectroscopy. X-ray diffraction work on ReOCl2(PPh3)(5,7-dibromo-oxinate) confirmed the trans-oxo-phenoxo-cisP,N arrangement about the Re centre. The information on the HOMO-LUMO gap was obtained from the position of the
lowest-energy transition observed in the visible spectra near 12000 cm-1. The gap for the 2:1 complexes was found to be
systematically smaller than for the 1:1 compounds. Within a given series, substitution on the phenolate ring showed no
appreciable effect, but the presence of a donor methyl group in 2-methyl-oxine increased the energy gap. On this basis, it is
concluded that our efforts should be directed to substitution on the pyridine ring and that electron-attracting groups should be
introduced, preferably at the ortho position.
P-14. Reactivity of Electrophilic Terminal Phosphinidene Complexes: P-P Bond Forming Reactions with Phosphines
and Diphosphines
Ozan Sanli Senturk, Brian T. Sterenberg, Konstantin A. Udachin and Arthur J. Carty*
Steacie Institute for Molecular Sciences, National Research Council Of Canada, 100 Sussex Drive, Ottawa, Ontario, Canada
K1A 0R6
Transition-metal phosphinidene complexes can be considered analogues of carbene complexes. It has been suggested that,
like carbenes, they can be divided into nucleophilic and electrophilic classes. We recently reported the first stable elecrophilic
phosphinidene complexes, and have described the reactivity of the molybdenum phosphinidene complex with phosphine and
diphosphines. In this study, we examine reactions of the tungsten phosphinidene complex [Cp*W(CO) 3{PNiPr2}][AlCl4] with
phosphines and also describe some reactions of the phosphine coordinated phosphinidine complexes. Reaction of the
tungsten phosphinidene complex [Cp*W(CO)3{PNiPr2}][AlCl4] with PEt3 results in carbonyl substitution at tungsten to
form [Cp*W(CO)2(PEt3){PNPr2}] [AlCl4], 1. Reactions with the diphosphines dmpm Me2PCH2PMe2 and (dmpe)
Me2PCH2CH2PMe2 were also investigated. In the dmpm reaction, one end of the diphosphine coordinates to the
phosphinidene phosphorus atom while the other end displaces a carbonyl from metal to form [Cp*W(CO)2 2P(NiPr2)P(Me2)CH2P(Me2)}][AlCl4], 2. Two products were obtained from the reaction of [Cp*W(CO) 3{PNiPr2}][AlCl4]
2
with dmpe, [Cp*W(CO)2
-P(NiPr2)P(Me2)CH2CH2P (Me2)}][AlCl4], 3, which is analogous to the dmpm derivative and
i
[Cp2*W2(CO)2 {=PN Pr2}2
-P(Me2)CH2CH2P(Me2)}][AlCl4], 4, in which the phosphine bridges between two tungsten
2
phosphinidene. The photochemical reaction of [Cp*Mo(CO) 2
-P(NiPr2)P(Me2)CH2CH2P(Me2)}] [AlCl4] in THF yields
i
2
in [Cp*Mo(CO){=PN Pr2
-P(Me2)CH2CH2P(Me2)}][AlCl4], 5. Loss of a carbonyl results in migration of one end of the
diphosphine from the phosphinidene to the metal. Structural and spectroscopic properties of the phosphinidene and
phosphine-coordinated phosphinidene complexes will be discussed.
P-15. Pd(II) -Diimine Ethylene Polymerization Catalysts: Anion Effects and Methide Abstraction Chemistry
John Brownie1, Michael C. Baird1, Lev N. Zakharov2 and Arnold L. Rheingold2
1
Department of Chemistry, Queen’s University, Kingston, Ontario, Canada
2
Department of Chemistry, University of Delaware, Newark, Delaware, U.S.A.
Numerous studies have demonstrated the importance and influence of the anion on catalyst activity and polymer
characteristics in early transition metal systems. However, very little work has been reported which has investigated the
effect of the anion in late transition metal -diimine catalyzed polymerizations. Herein we report the effect of several
different anions on the polymerization of ethylene using a Pd(II) -diimine complex, 1. In addition, we report on the reaction
of various methide abstraction agents with our Pd(II) -diimine complex to form a hitherto unknown dipalladium species, 2,
that is believed to be a high energy species associated with the catalytic cycle.
25
Ar
Ar
N
2
Ar
N
Me
Pd
+ Activator
Me
N
-
+ X + CH 4
Pd
C
H2
N
Ar
N
Me
Pd
+
Ar
N
Ar
Ethylene polymerization Initiator
1
2
P-16. The Structure of [Re(H2)H2(CO)L3]+ (L = Phosphine) Revisited.
Dmitry G. Gusev
Department of Chemistry, Wilfrid Laurier University, Waterloo, Ontario, Canada
The unstable polyhydride of rhenium [ReH4(CO)L3]+ has been studied by NMR spectroscopic (L = PPhMe2, PMe3)1, 2 and
theoretical computational (L = PH3)3 methods. This complex exits in solution as an equilibrium mixture of tetrahydrido (1)
and dihydrido-dihydrogen (2) isomers. The structure of 1 has been commonly agreed to be dodecahedral, as shown in the
accompanying Scheme. Different structural interpretations have been proposed in the literature for the pentagonal
bipyramidal isomer 2. Structures 2a and 2b were initially assigned by the experimental chemists. 1, 2 The subsequent
computational work3 (with L = PH3) rejected structure 2a because of its instability, and (without considering 2b) suggested
that isomer 2 should have the structure 2c.
We have carried out DFT calculations for 1 and 2a-c with the real ligands, L = PMe3. The computational work has revealed
that 2b is theoretically the most stable of all isomers shown above and, thus, most likely represents the solution structure of
the non-classical isomer, [Re(H2)H2(CO)(PMe3)3]+.
L
H
H
C
O
L
L
H
e
R
L
1
H
H
L
H2 e
R
L
H
O
C
2a
H
L
L
H2
e
R
H
L
H
L
H
O
C
2b
L
e
R
C
O
2c
H2
L
References:
1. Luo, X.-L., Crabtree, R. H. J. Am. Chem. Soc. 1990, 112, 6912. 2.Gusev, D. G.; Nietlispach, D.; Eremenko, I. L.; Berke,
H. Inorg. Chem. 1993, 32, 3628. Gusev, D. G.; Berke, H. Chem. Ber. 1996, 129, 1143. 3. Lin, Z.; Hall, M. B. J Am. Chem.
Soc. 1994, 116, 4446.
P-17. Preparation of 1,3,5-MLn Substituted Benzenes by Cyclo-condensation
Francis O. Ogini, Yannick Ortin, Mike McGlinchey, Ignacio Vargas-Baca, Amir Mahmoudkhani
Department of Chemistry, McMaster University, Hamilton, Ontario, Canada
It is known that some organometallic moieties, such as ferrocenyl and cymantrenyl groups, can be used to stabilize
developing adjacent carbocationic centers. Under some circumstances these intermediates are stable enough to be isolated
and characterized. In others cases these intermediates are relatively transient, but their unique properties enable a number of
interesting reactions. An example of this is illustrated in the condensation of certain acetyl-organometallic complexes in the
presence of tretrachlorosilane in ethanol. The reaction proceeds through the intermediate dimer, 1, to give 1,3,5-MLnsubstituted Benzenes (2). The structures of a number of these ferrocenyl and cymantrenyl trimers and dimmers have been
determined by X-ray crystallography and compared with each other. Our long-term goal is to create rigid molecules using
26
this convenient method of trimerisation. We are especially interested in the non-linear optical and electrochemical properties
of these compounds.
CH3
R
OH
+
OH
OH
-H3O+
+
H3 C
R
H2 C
CH3
OH
O
R
R
R
(1)
H
R
enolise
CH3
R
R
CH3
O
R
CH3
R
OH
-H3O+
+
HO
OH
H2 C
OH
+
R
R
R
R
R
H
H
H
enolise
R = (C5H4)Mn(CO)3 or (C5H4)Fe(C5H5) or both
R
R
R
CH2
OH
H
R
R
R
H
H
OH
R
-H2O
H
H
R
R
(2)
H
H
H
P-18. Alkyl Isomerization and Olefin Exchange in Three Coordinate Iron(II) Complexes: Models for -Olefin
Polymerization Catalysts
Javier Vela, Jeremy M. Smith, Rene J. Lachicotte, and Patrick L. Holland
Department of Chemistry, University of Rochester, N.Y.
Low coordinate alkyl complexes of the late transition metals are relevant as models for the active catalysts in -olefin
polymerizations. We have found that tertiary-butyl iron(II) diketiminates readily undergo thermal isomerization to the less
hindered iso-butyl complexes through unobserved olefin-hydride intermediates (see scheme, part a). In support of this
intermediate, iso-butyl complex 1 quantitatively yields the corresponding ethyl complex 2 upon heating with ethylene.
Kinetic analysis of this reaction showed a first order dependence on [1] and a zero order dependence on ethylene
concentration, consistent with a -hydride elimination path (b). Activation parameters (20 - 90C range) for the isomerization
and olefin exchange reactions are presented and their resemblance to chain walking and chain transfer steps in polymerization
processes are discussed. X-ray crystallography shows that these alkyl complexes remain three coordinate and free of agostic
interactions in the solid state.
Ar
R
a)
Ar
R
N
N
Fe
Fe
N
R
Ar = 2,6-diisopropylphenyl
R = tert-Bu or M e
N
R
Ar
Ar
b)
Ar
N
Ar
N
Fe
N
1
H
N
Fe
N
Ar
Ar
+
Ar
Ar
H
N
Fe
-
N
Fe
N
Ar
Ar
2
27
P-19. Synthesis of Amphiphilic Biomimetic Block Copolymers by Ring Opening Metathesis Polymerization
Jean Bouffard, Hassan S. Bazzi and Hanadi F. Sleiman*
Department of Chemistry, McGill University, 801 Sherbrooke West, Montreal, Quebec H3A 2K6
Some of the characteristic features of natural nucleic acid polymers, such as controlled sequence, hydrophilic backbone,
hydrophobic side-groups possessing complementary multiple hydrogen bonding receptors, were introduced in the design of
synthetic amphiphilic block copolymers. Substituted norbornene monomers possessing linear acceptor-donor-acceptor
(ADA) and donor-acceptor-donor (DAD) hydrogen bonding receptors as side-groups were prepared. Block copolymers were
prepared by controlled ring-opening polymerisation using first generation Grubbs' catalyst. The resulting polymer backbone
was dihydroxylated using catalytic Os(VIII) strategies. The self-assembly of triblock copolymers containing complementary
hydrogen-bonding receptors was studied by NMR and TEM, and shows reversible guest-dependent self-assembly and
aggregation.
P-20. Characterization of Rat S-Nitrosohemoglobin S-Nitrosation, NO Release, Effects of CuZn-SOD as well as Metal
Chelaotors on CuZn-SOD Properties
Mengwei Ye and Ann English
Department of Chemistry & Biochemistry, Concordia University, Montreal, Quebec, Canada
S-Nitrosohemoglobin (SNO-Hb) has been suggested to act as an endogenous NO donor and physiological regulator of blood
pressure. Understanding the reactions of nitric oxide (NO) with hemoglobin (Hb) under physiological conditions and to test
models of NO transport on hemoglobin and also the mechanism NO release from SNO-Hb is vital to elucidating the
metabolic fate of NO in the vasculature. The objective of this study is to elucidate the mechanisms responsible for the
formation of SNO-Hb and to examine the role of copper, zinc-superoxide dismutase (CuZn-SOD) in the release of NO from
SNO-Hb, and the effects that metal chelatores act on CuZn- SOD. Because rat model used frequently for in vivo studies, a
comparison was also made between the reactive cysteine residues in rat and Human Hb. According to the present study, Rat
Hb has more reactive Cys than human Hb and One Cys (Cysb93?) is highly reactive to S-nitrosation by CysNO or GSNO.
The results also indicated Free and SOD-copper catalyze S-NO breakdown in rat HbFeIIO2. So we hypothesis that CuZnSOD may play a key role in NO release from rat Hb-SNO in vivo if levels are high enough in rat RBCs. Our results
combining with those obtained from the literature will help us to reevaluate the significance of SNO-Hb in blood pressure
control.
P-21. Application of Near-Infrared Luminescence Spectroscopy for the Characterization of the Electronic Ground
State of Vanadium(III) Complexes.
Rémi Beaulac, Anne-Marie Boulanger, Jean-Christophe Tremblay and Christian Reber
Département de Chimie, Université de Montréal, Montréal, Québec, Canada
Characterization of the electronic structure of the ground-state of vanadium(III) complexes is a challenge to the
experimentalist. Near-infrared luminescence spectra of vanadium(III) complexes allow a direct observation of the energy
differences between levels of the electronic ground state ( 3T1g in Oh symmetry). Often though, the small energy differences
between states lying around 1000 cm-1- of the ground-state are hard to obtain because of low quantum yields of luminescence.
Low-temperature luminescence and/or Raman spectra are reported for [V(urea) 6]I3, for Cs[V(C2O4)2(H2O)2]4H2O, for
[VCl6]3- doped into Cs3AlCl6 and for [V(H2O)6]3+ in a series of doped alums. The highest energy luminescence transitions in
all spectra occur as sharp transitions between 9400 cm-1 and 10500 cm-1, and lower energy vibronic and electronic transitions
are observed at energies as low as 8000 cm-1. The ground state of the [V(urea)6]3+ complex is split into two trigonal
components separated by 1400 cm-1. This separation is larger than the corresponding energy difference reported for
Al2O3:V3+, even though the VO6 fragment in [V(urea)6]3+ is much closer to octahedral symmetry than in the doped oxide
lattice. [VCl6]3- in the doped chloride lattice shows a separation of approximately 1000 cm -1. [V(C2O4)2(H2O)2]1+ also shows
28
a ground state splitting energy on the order of 1300 cm-1. This splitting is shown in the case of [V(urea) 6]I3 to depend strongly
on the overlap between the d orbitals of the central metal and the ligands’ orbitals. Ligand field and density functional
calculations are used to rationalize this observation.
P-22. Optical spectroscopy of Nitronyl Nitroxide Radicals and of their Lanthanide Complexes
Rémi Beaulac1, Guillaume Bussière1, Christian Reber1, Christophe Lescop2 and Dominique Luneau2
1
Département de Chimie, Université de Montréal, Montréal, Québec, Canada
2
Laboratoire de Chimie Inorganique et Biologique, DRFMC, CEA-Grenoble, France
There is a huge interest to develop systems exhibiting spontaneous magnetization. Characterization of the electronic structure
of these materials is an important step in the understanding of single-molecule magnet properties. Optical spectroscopy can
help to gain a better description of the electronic structure of these compounds and to establish a link between their magnetic
and optical properties. Nitronyl nitroxide radicals and imino nitroxides radicals are among the most promising molecules in
that field. Low-temperature absorption and luminescence spectra of three crystalline nitronyl nitroxides are presented. For 2(2-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide
(NITPy)
and
2-(2-benzimidazolyl)-4,4,5,5tetramethylimidazoline-1-oxyl-3-oxide (NITBzImH), luminescence with resolved vibronic structure is observed between
700 nm and 1100 nm. The intensity distribution within the vibronic progressions indicate small structural changes between
the ground and emitting states. The lowest-energy absorption band systems observed between 450 nm and 700 nm of the two
luminescent compounds and of 2-cyano-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (NITCN) also show resolved
structure, but the overall width of these absorption band systems is larger by a factor of 2 than that of the luminescence
spectra. This difference is rationalized in terms of overlapping electronic transitions to at least two excited states arising from
the (SOMO-1)1(SOMO)2 and (SOMO)0(SOMO+1)1 electron configurations, supported by density functional calculations.
Luminescence spectra of lanthanide complexes with nitronyl and imino nitroxydes ligands are also reported. Again, the rich
vibronic structure shows that several excited states define the absorption spectra between 400 and 800 nm. We discuss the
qualitative trends that can be established between magnetic ground state properties and the energies of transitions and fine
structures of these complexes.
O
N
N
O
O
N
N
N
NH
O
O
N
N
O
N
N
NITCN
NITBzImH
NITPy
P-23. Characterization of Silica-Supported Vanadium Complexes Using X-Ray Absorption Spectroscopy
Eric W. Deguns,a Ziyad Taha,a George D. Meitznerb and Susannah L. Scotta
a
Department of Chemistry – University of Ottawa, Centre for Catalysis Research and Innovation ,b Department of Chemistry,
University of Texas at El Paso
The reaction of VOCl3 with hydroxyl-terminated silica gives a complex of form ≡SiOVOCl2 irrespective of the surface area
and initial hydroxyl content of the surface. Extended X-ray Absorption Fine Structure (EXAFS) spectra of the grafted
vanadium complexes on different silica surfaces are identical. Modelling the electronic scattering off vanadium and
subsequent refinement to the EXAFS data reveals the complex is pseudo-tetrahedral with two inequivalent chlorides and
29
oxygens in the first coordination sphere of the metal. Estimation of bond distances and angles of the complex was also
performed, demonstrating a viable way of characterizing model heterogeneous catalysts.
P-24. The Effect of Lead Oxide on the Optical Properties of Lead Zinc Borate Pr 3+-Doped Glasses
R. Naccache1, F. Vetrone1, C. Madwar1, J. A. Capobianco1, A. Speghini2 and M. Bettinelli2
1
Department of Chemistry and Biochemistry, Concordia University, Montreal, Canada
2
Dipartimento Scientifico e Tecnologico, Università di Verona, Ca' Vignal, Verona, Italy
Currently zinc borate glasses are regarded as attractive hosts to trivalent lanthanide ions due to the broad optical transparency
window ranging from 370 nm to 2.2
of tunable solid-state lasers. The dopant ion, Praseodymium, is a well studied lanthanide ion which finds its uses in many
optical hosts and is also used as an optical probe in studying dynamics of radiative and non-radiative processes such as crossrelaxation and multiphonon relaxation. This is mainly due to the numerous transitions from the emitting energy levels. In
addition, it is an attractive optical activator which offers the possibility of simultaneous blue, green and red emission for laser
3+
action, as well as IR emission for optical amplification at 1.3
doped Lead zinc borate
glasses were investigated (0 PbO, 2 PbO and 4 PbO). The absorption, emission, Raman spectra and lifetime measurements
are reported. The effect of PbO concentration in the glasses is discussed.
P-25. Synthesis of Unique FeII and CoII Complexes with Dipyrrolide Ligands Having Interesting Potential for Small
Molecule Activation
Jennifer Scott, Sandro Gambarotta, and Glenn P.A. Yap
Department of Chemistry, University of Ottawa
The activation and reduction of CO2 by transition metal complexes is attracting considerable attention for the purpose of
catalysis. We are aiming to find systems based on low-valent late transition metal comlexes with which to study step-by-step
reduction reactions that will hopefully be the foundations for the design of catalytic processes. The reaction of FeCl 2(THF)1.5
with one equivalent of the disodium salt of various dipyrrolyl ligands resulted in the formation of tetrameric divalent Fe
structures of the general formula [R2C(C4H3N)2Fe]4 (1) R=Ph ; (2) R=Et ; (3) R2=(CH2)5. In each of these complexes the
ligand pyrrolyl rings adopt both  and  bonding modes, thereby providing two different coordination environments to the
four metals. The reaction of FeCl2(THF)1.5 with two equivalents of the dipotassium salt of the cyclohexyldipyrrolylmethane
ligand resulted in the formation of the anionic metallate [(CH2)5C(C4H3N)2]2Fe[K(THF)]2. The analogous reaction with
CoCl2(THF)1.5 produced the crystallographically iso-structural complex.
P-26. Synthesis, Characterization and Surface Characteristics of Hexadecachloro- and HexadecafluoroRuthenium(II) Phthalocyanines
Mary Ann David, Dr. A.B.P. Lever, Dr. S. Morin
Department of Chemistry, York University, Toronto, Ontario, Canada.
Phthalocyanines have been extensively studied in various fields of interest such as light sensors, catalysis, molecular
semiconductors, electrochromic materials and electrocatalysts. The choice of ligand substituents on the phthalocyanines
strongly influences the redox properties of the metal complex. This study focuses on the highly substituted phthalocyanines
of Ruthenium and Cobalt. The newly synthesized hexadecachloro- and hexadecafluoro- phthalocyanines of ruthenium are
compared to that of the previously characterized cobalt species. The redox properties of the new highly substituted ruthenium
phthalocyanine species is of great interest to us and the catalytic properties of these complexes will be studied toward target
molecules such as carbon dioxide, thiols, alkanes or other such organic compounds. Phthalocyanines are known for the high
stability of their -electron system. They have a planar four-leaved structure. These molecules have been widely studied
using modern microscopic techniques. The stacking arrangement of phthalocyanines at the surface controls the access to the
central metal atom, the adsorption rate of the catalysts and surface coverage of the catalysts, which in turn affect the catalytic
30
reactions occurring at the surfaces. This study will include a detailed study of monolayers of the highly substituted metal
phthalocyanine complexes and their stacking order. The catalytic reactions occurring at these surfaces will also be examined.
P-27. Synthesis and Reactions of CrIII Complexes Having Nitrogen Donor and Alkyl Ligands
Hiroyasu Sugiyama, Sandro Gambarotta, and Glenn P. A. Yap
Department of Chemistry, University of Ottawa
-olefin polymerization catalysts due to their industrially relevant behaviour. As
an approach to this area, we have tried to develop complexes with nitrogen donor ligand systems, and clarify their reactivity.
The alkylation of Cr{2,6-bis[2,6-(i-Pr)2PhN=C(Me)]2(C5H3N)}Cl3 (1) with 3 equivalents of benzyl Grignard reagent resulted
in the formation of a dimeric CrII complex, {[2,6-(i-Pr)2PhNC(Me)]2(4-PhCH2C5H3N)Cr(CH2Ph)}2 (2) via (i) reduction of
CrIII centre, (ii) alkylation of Cr centre, and (iii) alkylation of the diiminopyridine ligand at the para position of the pyridine
ring with concurrent dimerization of the ligand. The reaction of 1 with milder alkylating agent, Al(CH3)3 was also examined
and produced a CrII complex, Cr{2,6-bis[2,6-(i-Pr)2PhN=C(Me)]2(C5H3N)}- {ClAl(CH3)3}2 (3) via reduction of the Cr centre.
This suggests instability of the CrIII-carbon bond. Analogous instability of the Cr III-carbon bond was also found in the CrIII
complex, Cr(CH3){(Ph)(Me)C( -C4H3N)2}(THF)2 (4), which was synthesized from the reaction between Cr(CH3)Cl2(THF)3
and the K salt of the corresponding dipyrrolide ligand, affording CrII complex, Cr
-C4H3N)2}(THF)2 (5) via
homolysis of the Cr-carbon bond.
P-28. Synthesis and Selective Chemical Vapor Deposition of Cu(II) Ketoiminate Complexes
Shan Lin1, 2, Chi Yun1and Arthur J. Carty2
1
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan
2
Steacie Institude for Molecular Sciences, National Research Council Canada, Ottawa,Canada
As a result of its low resistivity and ability to reliably carry high-current densities, copper is a reasonable alternative to more
commonly used contact materials, such as tungsten and aluminum in integrated circuits (ICs). Copper films can be deposited
by different techniques, such as sputtering, electrode-less or electrolytic plating and CVD (chemical vapor deposition). We
have synthesized a series of ketoimines, which have different number of fluorine atoms and different functional groups on the
nitrogen. These ketoimines were used to synthesize various copper CVD precursor complexes which were evaluated for their
volatility and reativity. Our results show that increased fluorine content results in better volatility,while bulky functional
groups on nitrogen result in better reactivity and thus lower substrate temperatures. Films were deposited on Si(100) and SiO 2
by using hydrogen as reactive carrier gas and the substrate temperatures in the range of 275 ~ 350 °C. Some of these
compounds can selectively deposit the copper film on the SiO 2, and not on the Si substrate. Patterned copper films can be
formed by depositing on a special substrate which has patterned SiO 2 on the surface of a Si substrate. These copper films
were characterized by scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and fourpoint probe technique, and show high purities and low resistivities.
P-29. The First Time Preparation of Superionic BaSnF 4 by the Wet Method
Georges Dénès , Tony Retrif and Abdualhafeed Muntasar
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
BaSnF4 is a high performance fluoride-ion conductor, and it is isostructural with α-PbSnF4 the latter being the highest
performance fluoride-ion conductor known to date. The exceptionally high mobility of the fluoride ions in the α-PbSnF4
structure has been ascribed to the disturbance brought about by the replacement of half the Pb 2+ ions in the fluorite-type
structure of β-PbF2 by covalently bonded Sn(II), and to the presence of a vacant fluoride-ion layer between two adjacent tin
layers. BaSnF4 was prepared first by one of us (GD) by direct reaction between SnF2 and BaF2 at 500oC, under dry
conditions, in inert atmosphere. For the synthesis of α-PbSnF4 in dry conditions, 250oC should be used since phase
transitions take place at higher temperatures. In addition, α-PbSnF4 can also be prepared by two wet methods: (i) α-PbSnF4
31
(aq1) precipitates when a solution of Pb(NO3 )2 is added to a solution of SnF 2, however, BaSnF4 cannot be prepared by the
same method, using Ba(NO3) 2, and (ii) α-PbSnF4 (aq2) is obtained by reaction of solid α-PbF2 with an aqueous solution of
SnF2, however, BaSnF4 could not be prepared by the same method, using BaF 2. Recently, a new method of preparation was
discovered in our laboratory, by leaching in water some barium tin(II) chloride fluorides, also newly discovered in our
laboratory. These new barium tin(II) chloride fluorides are prepared by precipitation either by adding a solution of SnF 2 to a
solution BaCl2 (Sn --> Ba) or vice-versa (Ba --> Sn), for a X molar ratio of BaCl2 in the reaction mixture. For the barium
tin(II) chloride fluorides prepared at high X values, and only if Ba --> Sn, the precipitate contains, in some cases, some
BaSnF4, together with either stoichiometric BaSnClF3.0.8H2O, or with the non-stoichiometric Ba1-xSnxCl1+yF1-y solid
solution. Pure BaSnF4 is obtained on stirring the precipitate in water for 24 hours, only for (0.735<X<0.870) and if Ba -->
Sn. Some of the properties of BaSnF4 prepared by the two methods have been investigated and compared to one another.
P-30. Phase Transitions in Superionic BaSnF4 upon Ball-Milling and Subsequent Treatments
Georges Dénès , Florence Grée and Abdualhafeed Muntasar
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
BaSnF4 is a high performance fluoride-ion conductor, and it is isostructural with α-PbSnF4, the latter being the highest
performance fluoride-ion conductor known to date. The exceptionally high mobility of the fluoride ions in the α-PbSnF4
structure has been ascribed to the disturbance brought about by the replacement of half the Pb 2+ ions in the fluorite-type
structure of β-PbF2 by covalently bonded Sn(II), and to the presence of a vacant fluoride-ion layer between two adjacent tin
layers. BaSnF4 was prepared first by one of us (GD) by direct reaction between SnF 2 and BaF2 at high temperature. Recently,
a new method of preparation was discovered in our laboratory, by leaching in water barium tin(II) chloride fluorides, also
newly discovered in our laboratory. In the present work, BaSnF 4 was ball-milled, and the samples were studied versus
ball-milling time. It was observed that, as expected, the particle size decreased with increasing ball-milling time. However,
for longer times, two phase transitions take place. First, a positional order/disorder transition takes place, with disappearance
of the cx2 superstructure, whereby barium and tin become randomly disordered. All the tin-lone pair axes are still parallel to
the c axis of the unit-cell, that is still tetragonal. For longer ball-milling times, an orientational order-disorder transition takes
places, with a tetragonal to cubic (Fm3m space group) lattice symmetry change, whereby the direction of all the tin-lone pair
axes are randomly distributed over the three axes of the cubic unit-cell. Like for PbSnF4, no further decrease of particle size
occurred upon further milling. The milling time required to obtain the phase transition was found to depend on the method of
preparation of BaSnF4. The cubic nanocrystalline BaSnF4 obtained on ball-milling,
μγ-BaSnF4, was found to change back
to the initial crystalline tetragonal BaSnF4 on annealing at 350oC. The cubic nanocrystalline BaSnF4 obtained on ball-milling
tetragonal BaSnF4 prepared by direct reaction at high temperature was also found to change back to the initial crystalline
BaSnF4 on stirring in water, whereas ball-milled BaSnF4 prepared by leaching barium tin(II) chloride fluorides in water gives
an amorphous material upon stirring in water. However, when this amorphous phase is annealed at 350oC, it also gives back
crystalline tetragonal BaSnF4.
P-31. Slow Kinetics of Phase Transitions in the Superionic PbSnF 4
Georges Dénès , Tristan Lechat, M. Cecilia Madamba and Sébastien Quinio
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
Superionic PbSnF4 exists under several phases, some of which differ from one another by their crystal structure, and some
others by some properties, closely related to their structures and crystal shape. The phase obtained is very much a function of
the method of preparation. In addition, many phase transitions are observed, some when temperature is varied, and others
upon ball-milling. Others take place upon stirring the solid in water. Several of the phase transitions involve a change of
type of order, or order/disorder phenomena. In addition, several of the phases are metastable, with some transformations
being very sluggish. It results that phase transitions take place at all kinds of temperatures, including low, high and ambient
temperatures. This makes PbSnF4 one of the most complicated materials. Since it is the highest performance fluoride-ion
conductor, potentials exist for practical applications. It has been used by others for the construction of an amperometric
oxygen sensor. Technological applications require stable properties in the conditions of use, over the lifetime of the device.
32
Properties such as the electrical conductivity are unlikely to be constant if phase transitions take place. Obviously, the
fluoride ion mobility changes at phase transitions, with the change of fluorine environment and number and types of defects
on the fluoride ion sublattice. Therefore, the presence of sluggish transitions is likely to cause a slow drift in the conductivity
of the material, and hence in the response of the device. It is therefore of prime importance to know which of the PbSnF 4
phases are stable over long periods of time, and which undergo slow phase transitions. This what the aim of the present
study. Samples of metastable -PbSnF4
-PbSnF4 above 300 oC under nitrogen in sealed copper
-PbSnF4 was prepared by short time ball-milling (1 minute
or longer). The ambient temperature stability of all phases of PbSnF4, and more particularly of the metastable phases, was
studied over various lengths of time, including after several year storage. In some cases, the stability at 100 oC was also
-PbSnF4 and o-PbSnF4 appear to undergo no phase transition even after a long storage
-PbSnF4
-PbSnF4 look stable over days, and even weeks, a slow
-PbSnF4
-PbSnF4, sometimes, a much faster partial transformation
-PbSnF4 is observed. This is uncontrollable, and probably depends on the number and distribution of crystal defects. All
transformations are accelerated at 100 oC, and are therefore thermally activated. In addition, for samples stored in air, a slow
surface oxidation, the kinetics of which is particle size dependent, is observed for all samples, and can be attributed to
imperfect passivation.
P-32. Influence of Temperature and pH on the Novel Preparation of Iron(III) Oxide and its Hydrates from Iron(II)
Georges Dénès , Matthieu Montassier and André L. Yonkeu
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
Hydrated iron oxides are major constituents of soils and sediments, and are produced in the corrosion of iron surfaces Their
dehydration results in the formation of iron(II) or iron(III) oxides or mixed oxidation states. Some of these have interesting
magnetic properties due to the various types of spin orders, and the presence of.non-stoichiometry results in semiconducting
properties for some of them. Iron(III) hydroxide has been traditionally prepared by addition of a base to a solution of an
iron(III) salt. This result in the preparation of a dark brown mud, that is a Fe(OH) 3. It was discovered by one of us (GD) that
a material with the same chemical composition can be prepared in slightly acidic medium, starting from iron(II) salts, and
that it is iron(III) oxide trihydrate, Fe 2O3.3H2O, rather than a hydroxide. In the present work, the preparation from iron(II)
has been explored further, by varying the pH and temperature of the reaction medium. It was found that, in all cases, the
materials produced was amorphous iron(III) oxide trihydrate, that dehydrates to Fe 2O3 hematite on heating, however, the
minimum temperature required to start getting hematite decreases with increasing pH. The average dimension of the
hematite particles increases with annealing temperature from ca. 10 nm (150 oC) to ca. 70 nm (1000oC).
P-33. Preparation of Iron(III) Oxide and its Hydrates from Iron(III) Versus Reaction Parameters
Mériadeg Charlou, Georges Dénès, and André L. Yonkeu
Department of Chemistry and Biochemistry, Laboratory of Solid State Chemistry and Mössbauer Spectroscopy, Laboratories
for Inorganic Materials, Concordia University, Montréal, Québec, Canada
Many hydrated iron oxides, natural and synthetic, have been reported. They are major constituents of soils and sediments,
and are important corrosion at iron surfaces. They are usually prepared in the laboratory by hydrolysis of a ferric solution in
highly basic conditions. This results in a gel that can take a very long time to dry. It was shown by one of us (GD) that the
resulting dark brown powder is antiferromagnetically ordered. It is amorphous and has superparamagnetic properties down
to 77 K. At 4.2 K, hyperfine magnetic field distribution is observed by Mössbauer spectroscopy. In the present study, the
preparation conditions were varied as follows: pH = 2.30 - 9.30, temperature of reaction mixture: ambient to 85 oC, annealing
temperature: 150oC to 1000oC. In acidic medium, no precipitation occurs at ambient temperature, however, at high
temperature, a precipitate is formed after standing 24 hours. In basic conditions, synthesis up to 45 oC result in amorphous
iron(III) hydroxide being produced. However, at 65 oC, a minor amount of crystalline FeOOH is also obtained. At 85oC, the
amount of FeOOH obtained is much higher. Annealing results in dehydration and recrystallization of hematite. The average
particle size of hematite increases linearly with increasing temperature, from ca. 13nm at 150oC to 70nm at 1000oC. On the
other hand, the particle dimension of FeOOH decreases from 27nm (not annealed) to 11nm (annealed at 250 oC).
33
P-34. A Palladium Catalyzed Stille-type Cross Coupling Route to α-Substituted Amines and Amino Acid Derivatives
Daniel A. Black, Jason L. Davis, and Bruce A. Arndtsen*. Department of Chemistry, McGill University, 801 Sherbrooke
Street West, Montreal, Quebec, Canada
Palladium catalyzed cross coupling reactions (e.g. Stille coupling) represent some of the more general and mild
methods to construct carbon-carbon bonds. While this transformation has been employed extensively with aryl and vinyl
halide substrates, its application to multiply bonded imine electrophiles, has not been explored, since imines themselves are
not prone to oxidative addition. We have recently developed a novel method to use imines as oxidative addition substrates.
This has been used to design a novel palladium catalyzed three component coupling of imines, acid chlorides, and
-substituted amides. The scope of this transformation and its application to synthesizing α -amino
acid derivatives will be described.
P-35. Nanopatterned Photochromic Thin Films via Molecular Self-Assembly
Adam J. Dickie, Florence Quist, Ashok K. Kakkar, and M.A. Whitehead
Department of Chemistry, McGill University, Montreal, Quebec, Canada
New technologies for fabrication of small-scale features on semiconductor materials must be achieved because of the
intrinsic size limitations of current photolithographic techniques, and because of the unwieldiness of new scanning probe
microscopic etching methods. Molecular self-assembly provides a rapid, in situ means to create novel inorganic-organic thin
films on semiconductor substrates; by using bifunctional surface initiators and understanding the natural film ordering, selfpatterning monolayers can be created. Si(100)/SiO 2 substrates are functionalized with mixtures of Si(NR2)4 / Sn(NR2)4, or
with bridged (NR2)3Si-O-X-CC-Sn(NR2)3 (X = -(CH2)n- , -C6H4-(CH2)n-) species to yield a chemically selective surface.
The addition of alkynyl chromophores (H-CC-(CH2)15CH3, H-CC-Ph) will produce adsorption at surface Sn-NR2 sites
only. Subsequent addition of long-chain alcohols causes adsorption at the remaining Si-NR2 positions, leading to
nanopatterned thin films with various surface densities. The appearance of self-assembling, photochromic crystals upon the
nanopatterned surface provides evidence for the utility and uniqueness of this thin film fabrication technique.
P-36. Nickel Catalysts with Functionalized Indenyl Ligands
L.F. Groux and D. Zargarian,
Département de Chimie, Université de Montréal
New nickel complexes bearing amino-functionalized indenyl ligands have been prepared and fully characterized.
The coordination of the amine moiety to the Ni centre has allowed the isolation of a new family of stable yet active cationic
complexes. The NNi binding strength in these complexes has been evaluated in order to better understand its influence on
the catalytic reactivities of these cations in the polymerization of olefins. This study has shown that the N-iPr2 moiety is the
most labile, presumably due to steric interactions, while the pyridine moiety binds the most strongly to the nickel centre.
Interestingly, the latter is also the most active in catalysis. Our preliminary results indicate that the reason for this unexpected
observation is that the catalysis involves the dissociation of the phosphine ligand, as opposed to the amine moiety.
+
N =
N
Ph3P
Ni
I
Cl
Ph3P
Ni
II
N
N
N
N
N
34
P-37. Fluorescent Probes for Spatio-Temporal Resolution of Nitric Oxide
Aaron J. Kosar and Scott Bohle*
Department of Chemistry, McGill University, 801 Sherbrooke Street West, Montreal, Quebec, Canada. McGill University
Detection of nitric oxide(NO) at biologically relevant levels favors the sensitivity of fluorescent probes. Reaction of NO with
2,3-diaminonaphthalenes in the presence of dioxygen results in the formation of highly fluorescent napthotriazoles. Current
probes based on diaminonaphthalene technology are limited to transport across cell membranes and to detection in the
aqueous milieu. Since NO diffuses from sites of production within the membrane, the syntheses of lipid-soluble derivatives
of 2,3-diaminonaphthalene were investigated.
P-38. New Pincer Complexes Containing a Bulky Diphosphinamine Ligand
Kamaluddin Abdur-Rashid,a Alan J. Loughb and Dmitry G. Guseva
a
Wilfred Laurier University, Department of Chemistry, Waterloo, Ontario N2L 3C5, Canada.
b
University of Toronto, Department of Chemistry, Toronto, Ontario M5S 3H6, Canada.
The reaction of [RuCl2(p-cymene)]2 with the diphosphinamine ligand 1,3-bis(N-(di-tert-butylphosphino)amino)propane in
the presence of a base produces a mixture of isomers of the olefin ruthenium complex,
RuHCl(tBu2PNHCH=CHCH2NHPtBu2), in equilibrium with the alkylidene ruthenium complex, RuHCl[=C(CH 2NHPtBu2)].
Procedures and progress towards the preparation of related osmium, rhodium and iridium species will be reported. The
spectroscopic properties and reactivity of the new complexes in activation of H2, carbon-hydrogen, carbon-carbon and
carbon-heteroatom bonds will be discussed.
P-39. Atomic layer epitaxy of titania multilayers on a silica template by non-hydrolytic condensation
Azfar Hassan, Susannah L. Scott
Center for Catalysis Research and Innovation, University of Ottawa, Ottawa, ON K1N6N5, Canada
We report a new, non-hydrolytic route for multilayer deposition of titanium(IV) onto a high surface silica.
Alternating gas-solid reactions of titanium tetrachloride and tert-butanol, which liberate HCl and tert-butyl chloride in
successive steps. The titanium content of this material increases linearly with the number of TiCl 4 additions.
P-40. Analysis of absorption bands with interference dips for octahedral Ni(II) complexes
Marie-Christine Nolet, and Christian Reber
Département de Chimie, Université de Montréal, Montréal, Quebec, Canada
Complexes with electronic states close in energy are interesting to study. Coupling between these states can occur and the
shape of the absorption band is different from the one expected. Information about the complexes can be gained by studying
the shape of the absorption band. The complexes studied are octahedral Ni(II) complexes; [(Tpm)Ni(NO 3)2],
[(Bpm)2Ni(NO3)](NO3), [(Tpm)2Ni]I2, [Ni(en)3]Cl2, [Ni(o-phen)3](NO3)2, [Ni(en)2(NCS)2] where Tpm is tris-(3,5dimethylpyrazol-1-yl)methane, Bpm is bis(3,5-dimethylpyrazol-1-yl)methane, en is ethylenediamine and o-phen is ophenantroline. All these complexes have the 3T2g and 1Eg states close in energy as confirmed by the absorption spectrum in
solution. A simple analytical equation was recently published [Neuhauser, D. et al. Phys.Rev.Lett. 2000, 85(25), 5304] to fit
the band. The complexes were chosen so that the ligand field strength is slightly different for all complexes. The physical
meaning of the parameters obtained from that equation will be discussed and compared to values obtained from other
methods.
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P-41. Synthesis and selective chemical vapor deposition of Cu(II) ketoiminate complexes
Shan Lin1, 2, Chi Yun1and Arthur J. Carty2
1
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan
2
Steacie Institude for Molecular Sciences, National Research Council Canada, Ottawa,Canada
As a result of its low resistivity and ability to reliably carry high-current densities, copper is a reasonable alternative to more
commonly used contact materials, such as tungsten and aluminum in integrated circuits (ICs). Copper films can be deposited
by different techniques, such as sputtering, electrode-less or electrolytic plating and CVD (chemical vapor deposition). We
have synthesized a series of ketoimines, which have different number of fluorine atoms and different functional groups on the
nitrogen. These ketoimines were used to synthesize various copper CVD precursor complexes which were evaluated for their
volatility and reativity. Our results show that increased fluorine content results in better volatility,while bulky functional
groups on nitrogen result in better reactivity and thus lower substrate temperatures. Films were deposited on Si(100) and SiO 2
by using hydrogen as reactive carrier gas and the substrate temperatures in the range of 275 ~ 350 °C. Some of these
compounds can selectively deposit the copper film on the SiO2, and not on the Si substrate. Patterned copper films can be
formed by depositing on a special substrate which has patterned SiO 2 on the surface of a Si substrate. These copper films
were characterized by scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy and fourpoint probe technique, and show high purities and low resistivities.
P-42. Properties of Molecules With Interference Dips in Electronic Spectra Using Multi-Dimensional Adiabatic and
Diabatic Potential Energy Surfaces
Emmanuel González and Christian Reber
Département de Chimie, Université de Montréal, Montréal, Québec, Canada
We use recently published analytical expressions1 to calculate and interpret interference dips in the electronic
absorption spectra caused when two or more molecular electronic excited states are coupled by spin-orbit coupling. We are
using multi-dimensional adiabatic and diabatic potential energy surfaces to obtain properties of molecules with interferences
and also to gain insight on the spectroscopic signatures of interacting potential energy surfaces. Examples of experimental
spectra with such dips2 are presented.
(1) Neuhauser, D.; Park, T.-J.; Zink, J. I. Phys. Rev. Lett. 2000, 85, 5304. (2) Schenker, R.; Triest, M.; Reber, C.; Güdel, H.
U. Inorg. Chem. 2001, 40, 5787.
P-43. Electron Transfer Reactions of Metal-Stoppered Cyclodextrin Rotaxanes
Shaheen Ahmed, Salima Nurmohamed, Michael Starzynski and Donal Macartney*
Department of Chemistry, Queen’s University, Kingston, ON K7L 3N6
Rotaxanes are supramolecular entities in which a cyclic host molecule is threaded by linear guest molecule, which is
stoppered by bulky end groups (organic or transition metal complexes) to prevent the dissociation of the rotaxane into its
cyclic and linear components. We have been interested in the properties of rotaxanes containing cyclodextrin (CD) as the
cyclic host and bis(4-pyridyl)-bridged transition metal dimer complexes as the stoppered threads (Baer and Macartney, Inorg.
Chem. 39 (2000), 1410-1417). With the appropriate metal complexes and conjugated bridging ligands, it should be possible
to prepare mixed-valence rotaxanes in which the cyclodextrin inclusion of symmetrical bridging ligand results in some
electron delocalization, as a result of the asymmetric cyclodextrin cavity. We have recently undertaken kinetic and
spectroscopic studies of the oxidation of two rotaxanes: [(NC) 5Fe{AZPCD}Fe(CN)5]6- and [(NC)5Fe{BPECD}Fe(CN)5]6(AZP = 4,4’-azopyridine and BPE = trans-1,2-bis(4-p
-CD), and their mononuclear
analog inclusion complexes, [Fe(CN)5{AZPCD}]3- and [Fe(CN)5{BPECD}]3-, using the outer-sphere oxidant [Co(dipic)2](dipic2- = 2,6-pyridinedicarboxylate), which does not form inclusion complexes with cyclodextrins. Factors responsible for
the observed decrease in the rate constants for the redox reactions in the presence of cyclodextrin host molecules will be
discussed.
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P-44. Deposition of Iridium Thin Films Using Iridium(I) CVD Precursors
Yao-Lun Chen1, 2, Yun Chi1 and Arthur J. Carty2
1
Department of Chemistry, National Tsing-Hua University, Hsinchu, Taiwan
2
Steacie Institute for Molecular Sciences, National Research Council Canada, Ottawa, Canada
Noble metal thin films are extensively studied by both the traditional and the microelectronics industrial communities for
potential applications such as anti-corrosion and anti-oxidation coatings, bottom electrodes for high-density memory devices,
and ferroelectric capacitors. Among these transition metal elements, iridium is considered one of the best targets as it
possesses a high work function, a stable conductive oxide phase IrO 2, and excellent electrical properties. Although the
physical sputtering seems to be a good choice for depositing such iridium metal-containing thin films, CVD will eventually
become a preferred method as it provides several promising advantages, such as a good conformal coverage, selective
deposition on the substrate surfaces, the capability for scale-up production with high throughput, and the ability to produce
meta-stable materials that can only be produced at low temperature. We have successfully synthesized six volatile Ir (I)
complexes and their physical properties relevant to CVD studies have been evaluated. Growth of thin films on Si (100) was
conducted using oxygen as reactive carrier gas and substrate temperatures in the range of 250 ~ 400 oC. These films,
characterized by scanning electron microscopy, X-ray powder diffraction, X-ray photoelectron spectroscopy, and four point
probe technique, show formation of iridium with purities greater than 98 % and measured resistivities below 11 cm.
P-45. The Synthesis and Reactivity of Mixed Nitrosyl/Phosphinidene Cluster of Ruthenium. Formation of Nitride and
Nitrene Clusters
Ludmila Scoles, Brian T. Sterenberg, Konstantin A. Udachin and Arthur J. Carty*
Steacie Institute for Molecular Science, National Research Council Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6
Over several years we have developed an extensive chemistry of substituted phosphinidenes on metal clusters, including the
synthesis of phosphorus monoxide (PO) complexes via acid catalysed hydrolysis of P-N bonds in co-ordinated
aminophosphinidenes. Since PO is a heavier congener of NO, and PR and NR are also analogous, we were intrigued by the
possibility of forming mixed PO/NO and NR/PR clusters. Reaction of the aminophosphinidene complex [Ru 5(CO)15(4PNiPr2) with [PPN][NO2] (PPN = Ph3P=N=PPh3) led to the formation of the mixed nitrosyl/phosphinidene cluster complex
[PPN][Ru5(CO)13(2-NO)(4-PNiPr2)]. Reaction of the nitrosyl cluster with HBF4.Et2O led to the nitrido/phosphido cluster
[Ru5(CO)13(5-N)(2-P(F)PNiPr2)] and the nitrene/phosphinidene cluster [Ru5(CO)10(-CO)2(3-CO)(4-NH)(3-PNiPr2)]. If
trifluoromethanesulfonic acid is used, [Ru5(CO)10(-CO)2(3-CO)(4-NH)(3-PNiPr2)] is only isolated product. Reaction of
[PPN][Ru5(CO)13(2-NO)(4-PNiPr2)] with methyltrifluoromethanesulfonate led to the formation of nitrido/phosphido cluster
[Ru5(CO)13(5-N){2-P(OMe)PNiPr2}]. The synthesis and characterisation of these complexes will be discussed, as well as
the mechanisms of their transformations.
P-46. Macrocyclic Rectangular and Triangular Platinum Complexes with Phosphine-substituted Poly-ynes. Ring Size
Control via Ancillarly Ligand Substitution at Platinum
Maria Paz Martin-Redondo, Brian T. Sterenberg, Konstantin A. Udachin, Arthur J. Carty*
Steacie Institute for Molecular Science, National Research Council Canada, 100 Sussex Dr., Ottawa, Ontario, K1A 0R6
Square planar transition metal complexes provide the ideal geometry for the corners of molecular squares and boxes, while
polyalkynes can provide straight linking units to join the vertices. In this study, we’ve examined platinum (II) complexes
with phosphine substituted poly-ynes. The phosphine substituted poly-yne Ph3PCCCCPPh3 (1) was prepared by reaction
of Cl2C=C(Cl)C(Cl)=CCl2 with LiBu, followed by treatment with Ph2PCl. Reaction of 1 with Pt(CH3)2(COD) leads to the
14-membered ring [{(CH3)2Pt}2(-Ph2PCCCCPPh2)2] (2) which contains two Pt centres bridged by two phosphine polyyne ligands, forming a rectangular structure. In contrast, reaction of Ph 3PCCCCPPh3 with PtCl2(COD) leads to the 21membered ring [{Cl2Pt}3(-Ph2PCCCCPPh2)3] (3) in which three platinum centres are bridged by three phosphine polyyne ligands, forming a triangular structure. Reaction of 2 with HCl results in conversion to 3. Changing the platinum
37
subsituents from methyl to chloro groups thus results in a redistribution of the the phosphine ligands and conversion from the
rectangular 2:2 complex to the triangular 3:3 complex. The phosphine-subtituted triyne ligand Ph3PCCCCCCPPh3 has
also been synthesized and Pt complexes with the longer linear spacers have been formed. The structural and spectroscopic
properties of these complexes will be discussed.
P-47. cis and trans-Pt(RNH2)2(NO3)2 Complexes: Aquation and Hydrolysis Products
Viorel Buculei and Fernande D. Rochon
Département de chimie,Université du Québec à Montréal, Montréal, Québec, Canada
Complexes of the types cis and trans-Pt(RNH2)2(NO3)2 were synthesized and characterized mainly by multinuclear ( 1H,
13C and 195Pt) magnetic resonance spectroscopy. The resonances of the cis complexes were observed at higher field (ave. =
-1698 ppm) than the trans isomers (ave. = -1573 ppm). The 195Pt coupling constants with the amine atoms 2,3J(195Pt-1H)
and 2,3J(195Pt-13C) are larger in the cis configuration than in the trans analogues. The aquation and hydrolysis reactions of
the cis and trans-dinitrato complexes were studied in different conditions of pH. In acidic solution, the diaqua species,
[Pt(RNH2)2(OD2)2]2+ were observed and the dihydroxo species, Pt(RNH2)2(OD)2 formed in basic pH. The chemical shifts
of the cis species are observed at much higher field than the trans analogues. In neutral pH, several species were observed,
especially for the cis complexes. Monomers of the type [Pt(RNH2)2(OD2)(OD)]+ and several oligomers like
[Pt(RNH2)2(OD2)2(-OD)]3+, [Pt(RNH2)2(-OD)22+ and [Pt(RNH2)2(-OD)]33+ were detected.
P-48. Crystal Structure Predictions: new Hf pnictides
Shahab Derakshan and Holger Kleinke
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
A novel structure map was recently presented for metal-rich pnictides and chalcogenides M2Q (M = valence-electron poor
transition metal, Q = pnicogen or chalcogen). This map separates the today known 12 M 2Q structure types into different
domains by plotting a newly defined power product against the averaged coordination number of the Q atoms. The power
product consists only of atomic factors, a fact which allows the design of a target type from atoms up [1]. We discuss the
ternary arsenides ZrTiAs [2] and ZrVAs [3], which both crystallize - in perfect agreement with our structure map - in the
La2Sb type. While Zr2As apparently forms the Zr2P type, the (to date) hypothetical "Ti2As" and "V2As" could not have been
prepared yet. Recently we found a new phosphide, namely HfTiP [4], which forms the predicted TiNiSi type. This
contribution deals with the structure map and its usability. We will present the crystal structures of HfTiP, ZrTiAs and
ZrVAs, and discuss their band structures and physical properties. We will also continue to make further predictions (e.g.
"HfTiAs" and "HfVAs" should both form the TiNiSi type as well). Time will tell how correct they are.
[1] H. Kleinke, B. Harbrecht, Z. Anorg. Allg. Chem. 626, 1851 (2000). [2] C.-S. Lee, E. Dashjav, H. Kleinke, Chem. Mater.
13, 4053 (2001). [3] E. Dashjav, H. Kleinke, J. Solid State Chem., in press. [4] S. Derakhshan, H. Kleinke, unpublished
research.
P-49. Thermoelectric Nowotny Chimney Ladder Phases
Navid Soheilnia, Yujia Zhu, and Holger Kleinke
Department of Chemistry, University of Waterloo, Waterloo, Ontario, Canada
Thermoelectrics are materials that can convert heat into electrical energy and vice versa. This fascinating energy conversion
is commercially used in power generators, air-conditioners, refrigerators, and for CPU cooling in laptops. Promising
materials consist of heavy elements and exhibit complex crystal structures with high thermal stability and medium charge
38
carrier concentrations (i. e. small-gap semiconductors). We are investigating the use of transition metal antimonides as
thermoelectric materials. The new binary antimonide Ti5Sb8 was prepared by arc-melting a mixture of Ti and TiSb2, or
alternatively, by annealing the mixture at 1000 °C in a Ta tube. The crystal structure of Ti 5Sb8 comprises a diamond-type Ti
atom substructure, interwoven with a nonclassical Sb atom network exhibiting Sb 6 'anchors' [1]. While the Ti atoms may be
replaced by Zr atoms up to the refined formula Zr 3.9(3)Ti1.1Sb8 [2], we recently succeeded in preparing a binary Zr antimonide,
Zr11Sb18 [3], with comparable structural motifs. These are the first pnictides that belong to the Nowotny chimney ladder
phases, which typically are tetralides of late transition elements, e.g. Ru 2Sn3, Ir4Ge5, Mn4Si7, Mn11Si19, Mn15Si26, and
Mn27Si47. The use of the Mn silicides as thermoelectrics has been patented in 1969 [4]. While Ti 5Sb8 itself is metallic, its
band structure reveals the presence of a band gap above the Fermi level, which may be reached by heavy doping. We are
currently exploring possibilities to synthesize quaternary chimney ladder silicide-antimonides.
[1] Y. Zhu, H. Kleinke, Z. Anorg. Allg. Chem., in press. [2] H. Kleinke, Inorg. Chem. 40, 95 (2001). [3] I. Elder, C.-S. Lee,
H. Kleinke, Inorg. Chem. 41, 538 (2002). [4] W. B. Bienert, F. M. Gillen, Martin-Marietta Corp., US Patent 3407037 (1969).
P-50. Unusual Temperature and Pressure Dependent Vibronic Features Observed in Thiocyanato and Selenocyanato
Complexes of Platinum(II) and Palladium(II)
John K. Grey1, 2, Ian S. Butler1, and Christian Reber2
1
Department of Chemistry, McGill University, Montréal, QC
QC
2
Département de Chimie, Université de Montréal, Montréal,
Transition metal complexes exhibit many interesting luminescence properties and often show promise for applications in
photochemical devices and solar cell sensitizers. When considering possible candidate systems, it is essential to understand
how excited state properties differ from those of the ground state have a means of quantifying these differences. We use
various spectroscopic and theoretical techniques to probe the ground and first excited electronic states of platinum(II) and
palladium(II) thiocyanato and selenocyanato complexes. These systems have D4h symmetry in the ground electronic state
and the observed luminescence is a metal-centered transition, assigned as 3Eg1A1g. The ambient pressure, low temperature
luminescence spectra of all complexes studied show long vibronic progressions in multiple vibrational modes, indicative of
markedly different molecular geometries in the excited states, with the totally symmetric metal-ligand stretching vibration
(a1g) forming the dominant progression. Additionally, the luminescence intensities and lifetimes vary strongly with
temperature demonstrating that nonradiative pathways are effectively blocked at lower temperatures. The ambienttemperature, high-pressure luminescence spectra of these systems show an unusually strong luminescence intensity increase
upon increasing pressure.1 Pressure-dependent luminescence lifetimes also show a concomitant increase, up to two orders of
magnitude from ambient pressure. We use the time-dependent theory of spectroscopy to calculate the luminescence spectra
and quantitatively determine emitting state distortions (i) along all Franck-Condon active modes. The temperaturedependent luminescence decay rates (kobs) are fitted using a two-state, single vibrational mode (eff) analytic model for the
strong coupling limit in radiationless decay theory. 2 Because pressure decreases the metal-ligand bond lengths, we decrease
eff in this model (at 275 K) and the nonradiative rate constant decreases exponentially, allowing us to rationalize the
increase in pressure-dependent lifetimes. These combined experimental and theoretical methodologies provide a means for a
better understanding of the effects of large changes between the ground and excited electronic states of coordination systems
and their potential utility in applications oriented fields.
1
J.K. Grey, I.S. Butler, C. Reber J. Am. Chem. Soc. 124 (2002) 9384.
R. Englman, J. Jortner Mol. Phys. 18 (1970) 145.
2
39
P-51. A Model for Gas-Phase Lanthanide-Water Clusters – The Importance of Polarization and Charge Transfer
Sean R. Hughes1, Tao-Nhan Nguyen1, John A. Capobianco1 and Gilles H. Peslherbe1
1
Department of Chemistry and Biochemistry, Concordia University, Montreal, Quebec, Canada
In recent years there has been a mounting interest in the use of lanthanide ions for numerous applications in inorganic solidstate chemistry and biotechnology. The modeling of the behaviour and the spectroscopy of lanthanide ions in diverse
environments, such as solvent clusters, aqueous solutions of bio-organic ligands or even sol-gels is of particular importance
in the design of novel, luminescent devices. We have chosen to develop model potentials based on first-principles quantum
chemistry calculations in order to simulate the structural properties of lanthanide ions in solvated environments. Preliminary
results suggest that polarizable and charge transfer terms are essential for reproducing the properties of small, gas-phase Ln3+water clusters obtained from high-level quantum chemistry calculations. Monte Carlo simulations of large Ln3+-water
clusters with these model potentials will also be discussed.
P-52. A Convenient Synthetic Route to 2H-Benz[cd]azulenes: Versatile Ligands That Can Bind Metals in an 2-, 5-,
6- or 7-Fashion.
Sonya Balduzzi and Micheal J. McGlinchey
Department of Chemistry, McMaster University, Hamilton, ON L8S 4M1
In continuation of our studies on haptotropic shifts, whereby organometallic moieties, MLn, migrate over polycyclic surfaces,
we sought a system made up of fused five-, six- and seven-membered rings with which a metal could adopt an 5, 6 or 7
mode of attachment. We anticipate that haptotropic shifts of a coordinated metal will be induced via changes in the oxidation
state of the polycyclic ligand itself. The synthesis of the first isolable 2H-benz[cd]azulene system is described, along with
routes for the introduction of an 5- or 6-complexed metal.