www.elsevier.nl/locate/ica
Inorganica Chimica Acta 293 (1999) 147 – 154
1:1 Adducts of triphenyltin chloride with oxovanadium(IV)
tetradentate Schiff-base complexes
Nosheen F. Choudhary a, Peter B. Hitchcock a, G. Jeffery Leigh a,*, Seik Weng Ng b
a
School of Chemistry, Physics and En6ironmental Science, Uni6ersity of Sussex, Falmer, Brighton BN1 9QJ, UK
b
Institute of Postgraduate Studies and Research, Uni6ersity of Malaya, 50603 Kuala Lumpur, Malaysia
Received 4 March 1999; accepted 3 May 1999
Abstract
Triphenyltin chloride– N,N%-ethylenebis(salicylideneiminato)oxovanadium(IV) (1/1), which crystallises from acetonitrile with
half a molecule of the solvent, is a heterodinuclear entity that displays an almost linear tin – oxygen – vanadium unit [SnOV=
172.7(2)°; SnO=2.382(2), VO=1.614(3) A, ]. The tin atom shows approximately trigonal bipyramidal coordination in the
adduct with the axial sites occupied by the O and Cl atoms. On the other hand, the vanadium atom is in square-pyramidal
coordination, and the vanadium-containing moiety is 68% displaced along the Berry pseudorotation pathway from trigonal
bipyramidal towards square pyramidal, compared with the 83% mean displacement for [VO(salen)] itself. The corresponding
displacements for the vanadium moiety in Ph3SnCl·VO(hap-1,2-pn)·2CH3CN are 94% [SnO=2.405(6), VO=1.627(6) A, ;
SnOV=175.5(3)°] and 89% in Ph3SnCl·VO[salen(3-OMe)2]·CH3CN [SnO= 2.428(2), VO= 1.625(2) A, ; SnOV= 167.5(1)°]
[H2hap-1,2-pn =N,N%-methylmethylenebis(2-phenolatoacetophenoneimine); H2salen(3-OMe)2 = N,N%-ethylenebis(3-methoxysalicylideneimine)]. The [VO(salen)] adduct of N-triphenylstannyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide has also been synthesised,
and characterised by spectroscopic measurements. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Crystal structures; Vanadium complexes; Oxo complexes; Schiff-base complexes; Tin complexes
1. Introduction
We have recently shown how vanadium(IV) compounds such as [VO(salen)] (1) [H2salen =ethylenebis(salicylideneimine)] may act as oxygen donors to compounds of vanadium(IV) and vanadium(V) [1]. Although these materials are not promiscuous donors,
they do form adducts with other Lewis acids, amongst
them organometallic compounds of tin such as
triphenyltin chloride and diphenyltin dichloride. However, structural data are lacking, and the range of such
adducts has not been established. We decided to investigate the range of such heterobimetallic tin – vanadium
adducts, since some such adducts have already been
reported [2a,b].
* Corresponding author. Tel.: + 44-1273-606 755; fax: +44-1273678 649.
Triphenyltin halides and pseudohalides furnish a
plethora of 1:1 complexes with oxygen-donors (E=O)
(E= C, S, Se, N, P, As) [4], so that adduct formation
with the rather poor vanadium-containing donors
might be possible. In contrast, neither triphenyltin
imides nor tin alkanoates generally form complexes.
p-Bonding to tin, and additionally association through
carboxylate for the alkanoates, are considered to give
rise to this behaviour. An exception amongst tin imides
is N-triphenylstannyl-1,2-benzisothiazol-3(2H)-one 1,1dioxide which forms a number of complexes with oxygen donors [5]. In addition, triphenyltin alkanoates can
display significant Lewis acceptor properties when a
0020-1693/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S 0 0 2 0 - 1 6 9 3 ( 9 9 ) 0 0 2 3 0 - 3
148
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
to stabilise adducts. We determined the structures of
three that are probably typical of all such species. The
five-coordinate vanadyl complex is a donor to tin, which
also becomes five-coordinate. The major surprise is that
the triphenyltin compound is such a good Lewis acid despite the fact that it carries three aromatic groups. One
might have expected a reduced acceptor ability compared with, say, SnCl4, such as happens with the lighter
Group 14 elements, but this is apparently not the case.
The structures themselves will be discussed below.
Although triphenyltin imides do not usually form adducts (as the tin–nitrogen bond reduces the Lewis acidity of the triphenyltin tin acceptor), N-triphenylstannyl-1,2-benzisothiazol-3(2H)-one is an exception to
this rule. We also isolated 1:1 adducts of some
vanadyl(IV) complexes with this imide (Table 1). The
stoichiometry, and spectroscopic data leave little doubt
that they are structurally analogous to the triphenyltin
chloride adducts discussed above, but unfortunately we
were not able to obtain any crystals.
Despite the rather crowded nature of the tin site, the
tin is still able to achieve five-coordination although Ntriphenylstannyl-4,5-benzisothiazol-3(2H)-one 1,1-dioxide reacts with neither [VO{salen(5-Cl)2}] nor
[VO{sal-1,2-pn(5-Br)2}] under our conditions.
Finally, we attempted to obtain adducts with
vanadyl(IV) complexes and the species Ph3SnOC(O)CH(S2CNMe2)·EtOH, but we were unsuccessful. This
may be because the tin compound coordinates the solvent ethanol preferentially.
strongly electron-withdrawing group is present. Thus
O-triphenyltin bis(N,N-dimethyldithiocarbamoyl)acetate, which has been isolated as an ethanol adduct [6],
forms a complex with quinoline N-oxide [7], as does,
S-triphenyltin isopropylxanthate, even though it has a
tin – sulfur link that should decrease Lewis acidity [8].
2. Results and discussion
2.1. Adducts characterised
We investigated adduct formation between three tin
compounds and various vanadyl(IV) Schiff-base adducts as detailed in Table 1. In only a few cases were we
able to isolate crystalline compounds, but we were able
to characterise the materials using elemental analysis,
and Mössbauer and IR spectroscopy. The IR band
assignable to n(VO) shows a characteristic drop of approximately 50 cm − 1 upon adduct formation, and the
colours of the adducts are always a rather dull green, orange or brown. The compounds [VO{salen(5-Br)2}],
[VO{sal-1,2-pn(5-Br)2}] and [VO{salen(5-Cl)2}], which
contain electron-withdrawing halides, and [VO(salnptn)] (H2salnptn= 1,2-HOC6H4CHNCH2C(Me)2CH2NCHC6H4OH-1,2), do not appear to react with
triphenyltin chloride in acetonitrile under our reaction
conditions. The reason may seem obvious for the first
three, but why the last does not do so is unclear. It may
be that the vanadyl donor is more distorted towards the
trigonal bipyramidal conformation and is thus a poorer
donor.
Nevertheless, it is evident that adduct formation is often facile and that several vanadyl Schiff bases are able
2.2. Structures of 6anadyl(IV) adducts
The X-ray crystal structures of three adducts related
to ours, [VO(salen)(SnPh2Cl2)]·H2O [7], [VO{salen(3-
Table 1
Adducts of oxovanadium(IV) complexes and tin compounds a
Adducts
[(salen)VO “SnPh3Cl]·0.5CH3CN
[{salen(5-Me)2}VO “SnPh3Cl]·0.5CH3CN
[{salen(3-OMe)2}VO “SnPh3Cl]·CH3CN
[(hapen)VO“SnPh3Cl]·0.25CH3CN
[(sal-1,2-pn)VO“SnPh3Cl]
[(hap-1,2-pn)VO“SnPh3Cl]·2CH3CN
[(salen)VO“SnPh3X]
[(hapen)VO“SnPh3X]
[(sal-1,2-pn)VO“SnPh3X]
Colour
green
green
brown
brown
green
brown
khaki
orange
green
n(VO) (cm−1)
1:1 adduct
Parent complex
943
934
934
926
943
927
930
908
946
989
959
991
991
986, 972
989, 973
989
991
986, 972
Isomer shift
(mm s−1)
Quadrupole splitting
(mm s−1)
1.34 9 0.02
3.25 9 0.03
1.359 0.01
3.15 9 0.02
1.37 90.04
1.32 90.02
3.33 9 0.06
3.50 9 0.04
a
H2salen =1,2-C6H4(OH)CHNCH2CH2NCHC6H4(OH)-1,2; additional substituents in the aromatic rings are indicated directly by 5-Me,
3-OMe, etc.; H2hapen =1,2-C6H4(OH)CMeNCH2CH2NCMeC6H4(OH)-1,2; H2sal-1,2-pn =1,2-C6H4(OH)CHNCMeHCH2NCHC6H4(OH)1,2; H2hap-1,2-pn = 1,2-C6H4(OH)CMeNCMeHCH2NCMeC6H4(OH)-1,2; X =1,2-benzisothiazol-3(2H)-one 1,1-dioxide. Mössbauer parameters for triphenyltin chloride: isomer shift 1.28 9 0.01, quadrupole splitting 2.54 9 0.01 mm s−1 and for N-triphenylstannyl-1,2benzisothiazol-3(2H)-one 1,1-dioxide: isomer shift 1.36 9 0.01, quadrupole splitting 3.10 9 0.02 mm s−1.
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
149
Table 2
Comparison of bond dimensions, distortions of coordination geometries and bond orders for [Ph3SnCl·VO(salen)]·0.5MeCN (1),
[Ph3SnCl·VO(hap-1,2-pn)]·2CH3CN (2), [Ph3SnCl·VO[salen(3-OMe)2]]·CH3CN (3), and [Ph3SnCl·VO(sal-1,2-pn)] (4) [3]
SnO (A, )
SnCl (A, )
SCSnC (°)
VO (A, )
VO (A, )
VN (A, )
VO“ Sn (°)
Displacement
Displacement
Displacement
Displacement
Displacement
towards TBP from SQ for Sn (%) [14]
towards SQ from TBP for V (%) [14]
of V from N2O2 plane (A, )
of Sn from best TBP centroid (A, ) [16]
V from best SQ centroid (A, ) [16]
1
2
3
4
2.382(3)
2.488(1)
357.5(5)
1.614(3)
1.895(3)
1.902(3)
2.044(4)
2.050(4)
172.7(2)
79.2
68.4
0.579(2)
0.074
0.304
2.405(6)
2.488(2)
358.7(9)
1.627(6)
1.896(6)
1.902(6)
2.063(7)
2.076(8)
175.5(3)
94.3
93.4
0.615(4)
0.055
0.311
2.428(2)
2.483(1)
357.0(3)
1.625(2)
1.908(2)
1.925(2)
2.050(2)
2.056(2)
167.5(1)
78.0
88.8
0.544(1)
0.055
0.312
2.424(9)
2.484(4)
not reported
1.617(9)
1.886(9)
1.905(8)
2.04(1)
2.05(1)
175.4(5)
89.2
78.5
0.563
0.055
0.304
Table 3
Comparison of selected bond lengths and angles in [(salen)VO “ SnPh3Cl]·0.5CH3CN and [(salen)VO“SnPh2Cl2]·H2O
Bond lengths (A, ) and angles (°)
[(Salen)VO“SnPh3Cl]
[(Salen)VO“ SnPh2Cl2]·H2O [2]
n(VO) (cm−1)
SnOV
OSnCl
VO
V removed from mean of N2O2 plane
VO(phenolate)
VN
SnO
943
172.7(2)
172.73(7)
1.614(3)
0.579(2)
1.902(3), 1.895(3)
2.044(4), 2.050(4)
2.382(3)
928
172.1
not reported
1.623(6)
0.6
1.903(5), 1.902(6)
2.055(7), 2.049(7)
2.335(6)
Table 4
Comparison of selected bond lengths and angles in [{salen(3-OMe)2}VO “SnPh3Cl]·CH3CN and [{salen(3-OMe)2}(H2O)VO “SnPh2Cl2]
Bond lengths (A, ) and angles (°)
[(L)VO“ SnPh3Cl]
[(L)(H2O)VO “SnPh2Cl2]·H2O [2]
n(VO) (cm−1)
SnOV
OSnCl
VO
V removed from mean of N2O2 plane
VO(phenolate)
VN
SnO
VOH2
934
167.48(10)
171.62(4)
1.625(2)
0.544(1)
1.908(2), 1.925(2)
2.056(2), 2.050(2)
2.428(2)
897
163.8(3)
not reported
1.635(5)
0.334
1.928(4), 1.919(4)
2.047(5), 2.054(6)
2.307(5)
2.321(5)
OMe)2}(H2O)(SnPh2Cl2)]
[2]
and
[VO(sal-1,2pn)(SnPh3Cl)] [3], have been described briefly. Our
three structures are similar. Significant structural data
are presented in Table 2, and comparisons of selected
dimensions are to be found in Tables 3 and 4.
The structure of [(salen)VO“SnPh3Cl] (1) (Fig. 1,
Tables 2 and 3) shows an almost linear VO(3)Sn
arrangement, with a bond angle of 172.7(2)°, and an
O(3)Sn bond length of 2.382(3) A, , where O(3) is the
vanadyl oxygen atom. The O(3)SnCl(1) bond angle is
172.73(7)°. The almost linear SnOV skeleton is not
usual, and most similar adducts are rather more bent
[9]. The linearity is therefore unlikely to arise from
electronic effects, and is probably a consequence of
lessening steric interactions between the ligands on
vanadium and tin. The tin atom shows trans-trigonal
bipyramidal coordination and the most electronegative
oxygen and chlorine atoms occupy the axial sites. The
tin–chlorine bond length [SnCl = 2.488(1) A, ] is increased by about 10% relative to those found in the
monoclinic and rhombohedral modifications of
triphenyltin chloride [10]. The bond angles about tin in
150
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
Fig. 1. ORTEP plot at the 50% probability level illustrating the
geometry of the vanadium and tin atoms in [VO(salen)SnPh3Cl]·0.5CH3CN.
the equatorial plane are C(17)SnC(23) at 126.2(4),
C(23)SnC(29) at 118.6(2), and C(17)SnC(29) at
112.7(2)°. The sum of these angles is close to 360°, so the
phenyl groups are coordinated in an almost planar,
though not exactly trigonal array. The tin – oxygen bond
distance [SnO = 2.382(3) A, ] compares well with that
[SnO = 2.391(4) A, ] found in the triphenylphosphine
oxide complex [11] but is much shorter than that
[SnO = 2.510(2) A, ] found in the ketone-donor 1,2diphenylcyclopropenone complex [12]. The distance is
significantly shorter than that [SnO = 2.424(9) A, ]
found in the N,N%-1,2-propylenebis(salicylideneimine)
complex, which has no solvent molecules in its crystal
structure [3].
The vanadium retains its five-coordinate, square
pyramidal geometry. There is a lengthening of the VO
double bond from 1.590(1) in [VO(salen)] to 1.614(3) A,
in the adduct. Vanadium is removed from the mean
plane of the N2O2 plane of the (salen)2 − unit in the
adduct by 0.579(2) A, , a little different from the value of
0.599 A, in [VO(salen)] itself [13]. The VO(phenolate)
bond lengths are 1.902(3) – 1.895(3), and the VN bond
lengths are 2.044(4) – 2.050(4) A, , little changed from
those in [VO(salen)].
The Lewis basicity of the vanadyl group might be
expected to be decreased by the delocalisation of electrons away from the vanadium – oxygen bond [3], but we
cannot assess this factor in our complexes. However, the
extent to which the donor molecule may be envisaged to
approach a square pyramidal structure may also be a
contributory factor in its function as a donor. One
method to probe the relationship between the two
extreme conformations of five-coordinate species, the
square pyramid (SQ) and the trigonal bipyramid (TBP),
is examination of the dihedral angles between adjacent
faces of the coordination polyhedron [14], which we
prefer to the alternative of considering bond angles [15].
The unit cell of the parent [VO(salen)] Lewis base
contains two symmetry-independent molecules of nearly
identical bond dimensions. In one, the displacement
along the Berry pseudorotation pathway from trigonal
bipyramidal to square pyramidal is 78% [14], much
closer to square pyramidal as might be expected. The
metal atom is 0.195 A, displaced from the best centroid
of coordination, which is defined as the idealised position of the central atom in a fully symmetrical coordination polyhedron [16]. The polyhedron in the other
molecule is somewhat less distorted (87% displacement
towards square pyramidal, and the metal atom is 0.187
A, from the best coordination centroid). On these geometrical grounds alone one might expect [VO(salen)] to
be a reasonable donor. Complexation seems to move the
vanadium away from the idealised best coordination
centroid, and towards TBP, though not by much. In
fact, [VO(salen)] is quite a good donor and has already
been reported to form a 1:1 adduct with the stronger
Lewis acid diphenyltin dichloride [2].
The adduct [{salen(3-OMe)2}VO“ SnPh3Cl] (3) (Fig.
2, Tables 2 and 4) was isolated as brown prismatic
crystals. On removal from the mother liquor the crystals
lose solvent and collapse. This affected the quality of the
data we were able to obtain. The low-temperature X-ray
diffraction again shows five-coordinate square pyramidal vanadium and trigonal bipyramidal tin. The vanadium is displaced from the mean plane defined by N2O2
by 0.544(1) A, , and the VO bond distance is 1.625(2) A, .
The three phenyl groups about tin are in the equatorial
plane, and arranged in a paddle-wheel formation, while
the chlorine is axial, trans to vanadyl oxygen. Angles
about tin in the equatorial plane are C(25)SnC(19)
115.94(9), C(19)SnC(31) 113.93(9), and C(31)Sn
C(25) at 127.17(9)°. The consequence is that the vanadyl
oxygen acts as a spacer between the relatively flat
Schiff-base plane and the volume occupied by the
Fig. 2. ORTEP plot at the 50% probability level illustrating the
geometry of the vanadium and tin atoms in [VO{salen(3OMe)2}SnPh3Cl]·CH3CN.
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
phenyl groups that are arranged in a propeller conformation about the tin. This creates a empty space that
can be filled by long, thin molecules such as CH3CN,
which is exactly what we observe here and in the
structure that follows. The O(5)“Sn bond distance is
2.428(2) A, , the O(5)SnCl bond angle is 171.62(4)°
and the central SnO(5)V bond angle is 167.5(1)°,
where O(5) is the vanadyl oxygen. This last is more
acute than the corresponding angle in [(salen)VO“
SnPh3Cl], 172.7(2)°. In the Schiff base, VO(phenolate)
bond distances are 1.908(2) and 1.925(2) A, , whilst VN
bond distances are 2.056(2) and 2.050(2) A, . The distortions from idealised geometries are similar to those
observed previously.
Finally, the adduct [(hap-1,2-pn)VO “SnPh3Cl] was
isolated as light brown crystals from the reaction of
[VO(hap-1,2-pn)] with triphenyltin chloride in acetonitrile after storage at −20°C for 2 days. On removal of
the crystals from the mother liquor they lose solvent
and collapse, so again X-ray diffraction studies were
carried out at low temperatures. Even with these precautions, the crystals studied were not of very high
quality and the final structure is not as good as we
would have wished. However, the general features are
quite clear.
The structure of [(hap-1,2-pn)VO “SnPh3Cl] (2)
(Fig. 3, Table 2) is very similar to those described
above, with the vanadyl oxygen donating to the tin.
The metal is displaced from the mean plane defined by
the N2O2 of the Schiff base by 0.615(4) A, . The vanadium oxygen double bond distance is 1.627(6) A, . Bond
angles about tin in the equatorial plane are
C(32)SnC(20) at 121.3(3), C(20)SnC(26) at
123.4(3), and C(32)SnC(26) at 114.0(3)°, the phenyl
groups are planar but not exactly trigonal. The O “ Sn
donor bond distance is 2.405(6) A, , with a VO(3)Sn
bond angle of 175.5(3) and an O(3)SnCl bond angle
151
of 176.6(1)°. In the Schiff base, VO distances are
1.896(6) and 1.902(6) A, , and VN distances are
2.076(8) and 2.063(7) A, . The departures from idealised
geometries are very like those described above.
The data allow us to compare the structures of our
adducts with those of SnPh2Cl2 in the literature [7]
(Tables 3 and 4). It is evident that the two salen
adducts in Table 3 are remarkably similar. The coordination about tin is also very similar except that in the
dichloride adduct the equatorial plane contains one
chloride and two phenyl groups rather than the three
phenyl groups in the monochloride adduct.
On the other hand, the adducts [{salen(3OMe)2}VO“ SnPh3Cl]) and [{salen(3-OMe)2}(H2O)VO“ SnPh2Cl2] (Table 4) are very different. The main
difference lies in the coordination geometry about
vanadium. In our adduct the vanadium is five-coordinate, whereas in the dichloride adduct it is six-coordinate with water coordinated to vanadium trans to
vanadyl–oxygen at a H2O“ V distance of 2.321(5) A, .
This compares with values of 2.292(4) and 2.456(3) A,
seen in [VO(salibn)(H2O)](CF3SO3) (H2salibn=1,2HOC6H4CHNCMe2CH2NCHC6H4OH-1,2) [17] and
[V(OH2)(salen)]+ [18], respectively. The metal is displaced from the mean plane defined by N2O2 by
0.544(1) in our adduct compared with 0.334 A, in the
other, due to the coordinated water. The coordinated
water also lowers the value of n(VO) in the IR spectrum from considerably more than 900 to 897 cm − 1 [7],
the decrease suggesting a weaker VO bond, even
though the VO bond lengths are very similar. Only the
O“ Sn bond distances differ appreciably, apparently
shortening upon coordination of water, as might be
expected.
N-Triphenylstannyl-4,5-benzisothiazol-3(2H)-one 1,1dioxide furnishes complexes with a range of vanadyl
donors, as detailed in Table 1. The Mössbauer data
allow us to infer their geometrical structures. All the
adducts show a drop in frequency of the band in the IR
spectrum assigned to n(VO) upon adduct formation.
This makes it likely that all the compounds contain the
moiety VO “ Sn, as observed in our structurally characterised materials. The magnitudes of these changes
are similar to those in the characterised adducts, and
there are no IR changes to suggest that other Schiff
base or imide oxygen atoms might be involved in
coordination. The stoichiometries of the adducts are all
1:1.
2.3. Mössbauer studies
Fig. 3. ORTEP plot at the 50% probability level illustrating the
geometry of the vanadium and tin atoms in [VO(hap-1,2pn)SnPh3Cl]·2CH3CN.
The Mössbauer spectroscopy were recorded at liquid
nitrogen temperatures, and the isomer shifts and
quadrupole splittings (with overall experimental errors)
are summarised in Table 1.
152
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
If we represent the adducts as five-coordinate tin
compounds of the form [R3SnL2], then three trigonal
bipyramidal configurations are possible, with one, two,
or three R groups in the trigonal plane. These should
show three different quadrupole splittings, reflecting the
asymmetry of electron density about 119Sn [19].
The Mössbauer spectra of triphenyltin chloride and
N-triphenylstannyl-4,5-benzisothiazol-3(2H)-one 1,1dioxide show an asymmetric doublet with isomer shifts
characteristic of tin(IV) compounds, which lie in the
range 0.5–2.0 mm s − 1. On adduct formation, the geometry about tin changes from tetrahedral to trigonal
bipyramidal. The quadrupole splitting for all of the
adducts tend to be larger than in the tin parent, suggesting an increased asymmetry of electron density
about tin(IV). The single doublet indicates the presence
of only one 119Sn site in the products.
All the Mössbauer spectra show asymmetric doublets. The reason for the asymmetry of the signal is not
clear, although this is an effect often observed in 119Sn
spectra. Parish states this may be due to crystalline
effects and/or the Goldanski – Karyagin effect, which, in
principle, occur whenever the Mössbauer atom occupies
a low symmetry site [20]. The doublets observed for
triphenyltin chloride, N-triphenylstannyl-1,2-benzisothiazol-3(2H)-one 1,1-dioxide, and all of the adducts
except the two formed from [VO(hapen)], show the
asymmetry in the same direction. For the adducts from
[VO(hapen)], the asymmetry observed is in the opposite
direction.
The quadrupole splittings in Table 1 show that all the
adducts contain five-coordinate tin with the three
phenyl groups that are bonded to tin lying in the
trigonal plane and the other two groups in trans-apical
positions. We conclude that all the adducts prepared by
us adopt this configuration.
2.4. NMR studies
It was not possible to obtain 119Sn NMR data for
[(salen)VO “SnPh3Cl], either in solution or in the solid
state, probably due to the paramagnetism of vanadium(IV). In any case, prolonged standing in solution
led to dissociation. For instance, if [(salen)VO “
SnPh3Cl] was left standing in acetonitrile or [{salen(3OMe)2}VO“SnPh3X] was left standing in dichloromethane, the VIV starting material was isolated, and
presumably the Lewis acid was left behind in solution.
It is unlikely that we can proceed further in this direction.
3. Experimental
All reactions were carried out under dinitrogen, using
standard Schlenk techniques unless otherwise stated.
Solvents used were dried as follows and distilled under
dinitrogen; acetonitrile was distilled over calcium hydride, dichloromethane and chloroform were pre-dried
over calcium chloride and distilled over calcium hydride. Both diethyl ether and tetrahydrofuran were
pre-dried over sodium wire and distilled over a
sodium–potassium alloy, and methanol was distilled
over magnesium methoxide.
IR spectra were obtained from dispersions in potassium bromide or as Nujol mulls using a Perkin–Elmer
model 1710 FTIR spectrophotometer. Carbon, nitrogen
and hydrogen analyses were carried out by Nicola
Walker at the University of Surrey on a Leeman CE
440 elemental analyser. 119Snm Mössbauer spectra were
recorded by Professor Bernard Mahieu, at the Université Catholique de Louvain, Belgium, at liquid nitrogen
temperatures and referenced against CaSnO3.
Oxobis(pentane-2,4-dionato)vanadium(IV) and its
homologues were prepared using standard literature
methods [21]. Triphenyltin chloride and triphenyltin
hydroxide were obtained commercially. N-triphenylstannyl-4,5-benzisothia-3(2H)-one 1,1-dioxide was synthesised by condensing triphenyltin hydroxide with
saccharin in toluene [5], and triphenyltin bis(N,Ndimethyldithiocarbamoyl)acetate ethanol by condensing
triphenyltin hydroxide with bis(N,N-dimethyldithiocarbamoyl)acetic acid in ethanol [6].
3.1. Reactions of triphenyltin chloride with 6anadyl(IV)
compounds
See footnote to Table 1 for an explanation of the
designations of the Schiff bases used.
3.1.1. [VO(salen)]
The compound [VO(salen)] (0.86 g, 2.57 mmol) was
dissolved in acetonitrile (80 cm3) and an equimolar
quantity of Ph3SnCl (0.99 g, 2.57 mmol) was added to
the green solution. The mixture was heated under reflux
for 2 h and then stored at 4°C for 4 days, to yield a
green crystalline solid that was collected and washed
with ether. Yield: 1.45 g, 76%. IR (KBr disc, cm − 1):
n(VO) 943. Found: C, 56.5; H, 4.2; N, 4.8. Anal. Calc.
for C34H29ClN2O3SnV·0.5C2H3N: C, 56.5; H, 4.7; N,
4.7%.
3.1.2. [VO{salen(5 -Me)2}]
The compound [VO{salen(5-Me)2}] (0.69 g, 1.91
mmol) was suspended in acetonitrile (100 cm3) and
triphenyltin chloride (0.75 g, 1.96 mmol) was added.
The green suspension was heated under reflux for 8 h to
give a light green powder which was then filtered off
and washed with diethyl ether (30 cm3). Yield: 1.00 g,
69%. IR (KBr disc, cm − 1): n(VO) 934. Found: C,
57.3; H, 4.4; N, 4.1. Anal. Calc. for C36H33ClN2O3SnV·0.5C2H3N: C, 57.9; H, 4.5; N, 4.2%.
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
3.1.3. [VO{salen(3 -OMe)2}]
The compound [VO{salen(3-OMe)2}] (3.52 g, 8.95
mmol) was suspended in acetonitrile (160 cm3) and
triphenyltin chloride (3.50 g, 9.08 mmol) was added.
The suspension was heated under reflux for 2.5 h to
give a deep green solution, which was filtered hot
through Celite and left to cool overnight to room
temperature (r.t.) to give prismatic brown crystals.
Yield: 6.02 g, 82%. IR (KBr disc, cm − 1): n(VO) 934.
Found: C, 55.6; H, 4.3; N, 5.1. Anal. Calc. for
C36H33ClN2O5SnV·C2H3N: C, 55.7; H, 4.4; N, 5.1%.
3.1.4. [VO(hapen)]
The compound [VO(hapen)] (0.72 g, 1.98 mmol) was
suspended in acetonitrile (50 cm3) and triphenyltin chloride (0.76 g, 1.98 mmol) was added. The suspension was
heated under reflux for 6 h, then cooled to r.t. As no
reaction had occurred, the volume of the solution was
reduced by half under vacuum with stirring. A brown
solid soon formed. On reheating the reaction flask,
traces of the green starting material, [VO(hapen)] could
be seen, so the flask was cooled slowly to r.t. and the
suspension was stirred for 2 days. The brown solid
formed was then filtered off and washed with diethyl
ether (30 cm3). Yield: 1.22 g, 81%. IR (KBr disc, cm − 1):
n(VO) 926. Found: C, 58.0; H, 4.3; N, 4.1. Anal. Calc.
for C36H33ClN2O3SnV·0.25C2H3N: C, 57.9; H, 4.5; N,
4.2%.
3.1.5. [VO(sal-1,2 -pn)]
The compound [VO(sal-1,2-pn)] (1.25 g, 3.61 mmol)
was dissolved in acetonitrile (60 cm3) to afford a green
solution. Triphenyltin chloride (1.39 g, 3.60 mmol) was
added and the solution was heated under reflux for 2 h.
It was then filtered hot through a layer of Celite to
remove any unchanged material and the filtrate was
stored at 4°C for 5 days. A dark green crystalline solid
was filtered off and washed with diethyl ether (40 cm3).
Yield: 2.19 g, 83%. IR (KBr disc, cm − 1): n(VO) 943.
Found: C, 56.8; H, 4.0; N, 3.7. Anal. Calc. for
C35H35ClN2O3SnV: C, 57.1; H, 4.8; N, 3.8%.
3.1.6. [VO(hap-1,2 -pn)]
The compound [VO(hap-1,2-pn)] (0.80 g, 2.13 mmol)
was suspended in acetonitrile (80 cm3) and triphenyltin
chloride (0.86 g, 2.23 mmol) was added. The suspension
was heated under reflux for 3 h, and a brown crystalline
solid was isolated after storing the solution at −20°C
for 2 days. On removing the crystals from solvent they
collapsed, losing solvent. A small crop was recrystallised
from acetonitrile for X-ray diffraction studies at low
temperature. Yield: 1.07 g, 66%. IR (KBr disc, cm − 1):
n(VO) 927. Found: C, 58.1; H, 4.5; N, 3.6. Anal. Calc.
for C37H35ClN2O3SnV: C, 58.4; H, 4.6; N, 3.7%.
The compounds [VO{salen(5-Br)2}], [VO{sal-1,2pn(5-Br)2}], [VO{salen(5-Cl)2}], and [VO(salnptn)]
(H2salnptn=1,2-HOC6H4CHNCH2C(Me)2CH2NCH-
Table 5
Crystal data and structure refinement for new adducts
Compound
[VO(salen)SnPh3Cl]·
0.5CH3CN
[VO(hap-1,2-pn)SnPh3Cl]·
2CH3CN
[VO{salen(3-OMe)2}SnPh3Cl]·
CH3CN
Empirical formula
Formula weight
Temperature (K)
Crystal system
Space group
Unit cell dimensions
a (A, )
b (A, )
c (A, )
a (°)
b (°)
g (°)
Volume (A, 3)
Z
m(Mo Ka) (mm−1)
F(000)
Crystal size (mm)
u Range for data collection (°)
Reflections collected
Independent reflections
[Rint = 0.019]
Reflections with I\2s(I)
Data/restraints/parameters
Final R indices [I\2s(I)]
R indices (all data)
C34H29N2O3ClVSn·0.5CH3CN
739.2
293(2)
monoclinic
C2/c (no.15)
C37H35N4O3ClVSn·2CH3CN
842.9
173(2)
triclinic
P1( (no. 2)
C36H33N2O5ClVSn·CH3CN
819.8
173(2)
triclinic
P1( (no. 2)
31.592(5)
11.582(9)
20.471(3)
6385(5)
8
1.20
2976
0.50×0.20×0.10
2–25
5701
5604
11.257(5)
12.309(4)
15.075(4)
72.90(2)
82.74(3)
70.28(3)
1879(1)
2
1.03
858
0.3×0.3×0.1
2–25
6561
6561
11.739(3)
12.187(2)
13.586(3)
81.82(2)
68.84(2)
81.44(2)
1784.1(7)
2
1.08
830
0.25×0.25×0.08
2–25
6259
6259
4545
5602/0/394
R1 = 0.036, wR2 = 0.085
R1 = 0.051, wR2 = 0.094
5534
6561/0/460
R1 =0.076, wR2 =0.237
R1 =0.090, wR2 =0.271
5750
6259/0/442
R1 =0.025, wR2 =0.064
R1 =0.029, wR2 =0.066
121.53(1)
153
154
N.F. Choudhary et al. / Inorganica Chimica Acta 293 (1999) 147–154
C6H4OH-1,2) do not appear to react with triphenyltin
chloride in acetonitrile under our conditions.
Professor Bernard Mahieu, Université Catholique de
Louvain, Belgium, with the Mössbauer spectroscopy.
3.2. Reactions of N-triphenylstannyl-4,5 -benzisothiazol3(2H) -one 1,1 -dioxide with 6anadyl(IV) compounds
References
3.2.1. [VO(salen)]
N-Triphenylstannyl-4,5-benzisothiazol-3(2H)-one 1,1dioxide (1.51 g, 2.61 mmol) was dissolved in ethanol (40
cm3) and [VO(salen)] (0.87 g, 2 mmol) was added. The
solution was heated to reflux for 2 h and then cooled to
r.t. A khaki solid was filtered off and washed with
diethyl ether (40 cm3). Yield: 2.08 g, 92%. IR (KBr disc,
cm − 1): n(VO) 930. Found: C, 56.6; H, 3.6; N, 4.9.
Anal. Calc. for C41H33N3O6SSnV: C, 56.9; H, 3.8; N,
4.9%.
3.2.2. [VO(hapen)]
The compound [VO(hapen)] (1.20 g, 3.32 mmol) was
suspended in ethanol (60 cm3) and N-triphenylstannyl4,5-benzisothiazol-3(2H)-one 1,1-dioxide (1.92 g, 3.32
mmol) was added. The solution was heated under reflux
for 1 h. A change from green to brown occurred within
30 min. The solid formed was filtered off and washed
with diethyl ether (30 cm3). Yield: 1.99 g, 67%. IR (KBr
disc, cm − 1): n(VO) 908. Found: C, 57.9; H, 4.0; N,
4.8. Anal. Calc. for C43H37N3O6SSnV: C, 57.8; H, 4.2;
N, 4.7%.
3.2.3. [VO(sal-1,2 -pn)]
The compound [VO(sal-1,2-pn)] (1.01 g, 2.91 mmol)
was dissolved in acetonitrile (70 cm3) to afford a green
solution. N-Triphenylstannyl-4,5-benzisothiazol-3(2H)one 1,1-dioxide (1.67 g, 2.91 mmol) was added and the
solution was heated under reflux for 2 h. A light green
powder formed. This was filtered off and washed with
diethyl ether (40 cm3). Yield: 1.76 g, 69%. IR (KBr disc,
cm − 1): n(VO) 946. Found: C, 57.2; H, 3.8; N, 4.7.
Anal. Calc. for C42H35N3O6SSnV: C, 57.4; H, 4.0; N,
4.8%.
The details of the crystal structure determinations are
summarised in Table 5.
4. Supplementary material
Atomic coordinates and equivalent isotropic displacement parameters for 1, 2 and 3 can be obtained
from G.J.L. or the Cambridge Crystallographic Database.
Acknowledgements
We acknowledge the award of an EPSRC Studentship to N.F.C., and the most generous help of
.
[1] (a) D.L. Hughes, U. Kleinkes, G.J. Leigh, M. Maiwald, J.R.
Sanders, C. Sudbrake, J. Chem. Soc., Dalton Trans. (1994) 2457.
(b) A. Hills, D.L. Hughes, G.J. Leigh, J.R. Sanders, J. Chem.
Soc., Chem. Commun. (1991) 827.
[2] B. Cashin, D. Cunningham, J.F. Gallagher, P. McCardle, Polyhedron 8 (1989) 1753.
[3] B. Cashin, D. Cunningham, J.F. Gallagher, P. McCardle, T.
Higgins, J. Chem. Soc., Chem. Commun. (1989) 1445.
[4] (a) J.A. Zubieta, J.J. Zuckerman, Prog. Inorg. Chem. 24 (1978)
251. (b) P.J. Smith, J. Organomet. Chem. Libr. 12 (1981) 97. (c)
P.G. Harrison, Dictionary of Organometallic Compounds, second edn., Chapman and Hall, London, 1995, pp. 4111–4240.
[5] (a) S.W. Ng, W. Chen, V.G. Kumar Das, T.C.W. Mak, J.
Organomet. Chem. 373 (1989) 21. (b) S.W. Ng, W. Chen, V.G.
Kumar Das, T.C.W. Mak, J. Organomet. Chem. 379 (1989) 247.
(c) S.W. Ng, A.J. Kuthubutheen, A. Zainudin, W. Chen, B.
Schulze, K.C. Molloy, W.-H. Yip, T.C.W. Mak, J. Organomet.
Chem. 403 (1991) 101. (d) S.W. Ng, V.G. Kumar Das, Z.-Y.
Zhou, T.C.W. Mak, J. Organomet. Chem. 424 (1992) 133. (e)
S.W. Ng, W. Chen, V.G. Kumar Das, Acta Crystallogr., Sect. C
48 (1992) 2211. (f) S.W. Ng, Acta Crystallogr., Sect. C 52 (1996)
1365. (g) J. Klein, B. Schulze, R. Borsdorf, S.W. Ng, J. Prakt.
Chem. 337 (1995) 242.
[6] S.W. Ng, V.G. Kumar Das, J. Organomet. Chem. 409 (1991)
143.
[7] S.W. Ng, Acta Crystallogr., Sect. C 53 (1997) 274.
[8] S.W. Ng, V.G. Kumar Das, M.G.B. Drew, Main Group Met.
Chem. 18 (1995) 303.
[9] A.L. Rheingold, S.W. Ng, J.J. Zuckerman, Inorg. Chim. Acta 86
(1984) 179.
[10] (a) J.S. Tse, F.L. Lee, E.J. Gabe, Acta Crystallogr., Sect. C 42
(1986) 1876. (b) S.W. Ng, Acta Crystallogr., Sect. C 51 (1995)
2292.
[11] S.W. Ng, V.G. Kumar Das, Acta Crystallogr., Sect. C 48 (1992)
1839.
[12] S.W. Ng, V.G. Kumar Das, J. Crystallogr. Spectrosc. Res. 23
(1993) 929.
[13] P.E. Riley, V. Pecoraro, C.J. Carrano, J.A. Bonadies, K.N.
Raymond, Inorg. Chem. 25 (1986) 154.
[14] R.R. Holmes, J.A. Dieters, J. Am. Chem. Soc. 99 (1977) 3318.
[15] (a) A.W. Addison, T.N. Rao, J. Reedijk, J. van Rijn, G.C.
Gerrit, J. Chem. Soc., Dalton Trans. (1984) 1349. (b) C.R.
Cornman, K.M. Geiser-Bush, S.P. Rowley, P.D. Doyle, Inorg.
Chem. 36 (1997) 6401.
[16] (a) T. Balic Zunic, I. Vickovic, IVTON, A Program for the
Calculation of Geometrical Aspects of Crystal Structures and
Some Crystal Chemical Applications, Geological Institute, University of Copenhagen, Denmark, 1994. (b) T. Balic Zunic, E.
Makovicky, Acta Crystallogr., Sect. B 52 (1996) 78.
[17] N.F. Choudhary, P.B. Hitchcock, G.J. Leigh, unpublished data.
[18] L. Banci, A. Bencini, A. Dei, D. Gatteschi, Inorg. Chim. Acta 84
(1984) L11.
[19] T Omae, J. Organomet. Chem. Libr. 21 (1989) 1.
[20] R.V. Parish, NMR, NQR, EPR and Mössbauer Spectroscopy in
Inorganic Chemistry, Ellis Horwood, Chichester, 1990, p. 125.
[21] J.R. Zamain, E.R. Dockal, Transition Met. Chem. 21 (1996)
370.