Synthesis, characterisation and structures of thio-, seleno- and telluro-ether complexes of indium(III) halides

Article abstract of DOI:10.1039/b816148h

The indium(III) halo-bridged octahedral dimers [InX₂(L-L)(μ- X)₂InX₂(L-L)] (X = Cl: L-L = MeS(CH₂) ₂SMe, MeSe(CH₂)₂SeMe, ⁿBuSe(CH ₂)₂Seⁿ

Full text of DOI:10.1039/b816148h

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Synthesis, characterisation and structures of thio-, seleno- and telluro-ether
complexes of indium(III) halides†
Chitra Gurnani,a,b Marek Jura,a William Levason,a Raju Ratnani,b Gillian Reid*a and Michael Webstera
Received 16th September 2008, Accepted 25th November 2008
First published as an Advance Article on the web 19th January 2009
DOI: 10.1039/b816148h
The indium(III) halo-bridged octahedral dimers [InX2(L–L)(m-X)2InX2(L–L)] (X = Cl: L–L =
MeS(CH2)2SMe, MeSe(CH2)2SeMe, nBuSe(CH2)2SenBu), the ionic trans-[InX2(L–L)2][InX4] (X =
i
Cl: L–L = PrS(CH2)2SiPr; X = Br: L–L = MeS(CH2)2SMe, iPrS(CH2)2SiPr, MeSe(CH2)2SeMe),
cis-[InCl2(thiamacrocycle)][InCl4] (thiamacrocycle = [12]aneS4 or [14]aneS4) and the neutral,
octahedral [InCl3([9]aneS3)] and [InCl3{MeC(CH2SMe)3}] were obtained in good yield by
the reaction of 1:1 molar ratios of InX3 with the ligand in anhydrous CH2Cl2 solution. The
distorted tetrahedral [InX3(Me2Se)] (X = Cl, Br or I) and [InX3(Me2Te)] (X = Br or I) were
obtained from 1:3 and 1:2 molar ratios respectively of InX3 and Me2E (E = Se or Te) also in
CH2Cl2. The ligand-bridged, distorted tetrahedral dimers [(InCl3)2{m2-o-C6H4(CH2SMe)2}] and
[(InCl3)2{m2-MeTe(CH2)3TeMe}] are formed even from a 1:1 In:ligand ratio. Key structure types were
confirmed from crystal structures of [InCl2{RSe(CH2)2SeR}(m-Cl)2InCl2{RSe(CH2)2SeR2}] (R = Me
i
or nBu), trans-[InX2{ PrS(CH2)2SiPr}2][InX4] (X = Cl or Br), trans-[InBr2{MeSe(CH2)2SeMe}2][InBr4],
cis-[InCl2([14]aneS4)][InCl4] and [InBr3(Me2Se)]. The bulk complexes have been characterised by IR and
1
1
Raman spectroscopy and microanalyses, while 1H, 77Se{ H} and 125Te{ H} NMR spectroscopy show
that the compounds are extremely labile in solution and undergo rapid dynamic exchange equilibria.
Comparisons are drawn between these structurally rather diverse In(III) chalcogenoether complexes
and the corresponding Ga(III) species (all of which are neutral and involve distorted tetrahedral
coordination). The reaction of TlCl3 with Me2E (E = Se or Te) shows that chlorination of Me2E rather
than adduct formation occurs, while no reaction occurred between TlCl3 and Me2S, consistent with
Tl(III) being a very poor Lewis acid.
corresponding ligand reactions with InX3 and a brief examination
of associated reactions with TlCl3.
Introduction
The indium(III) halides, InX3 (X = Cl, Br or I), have polymeric
structures with six-coordinate metal centres (b-In2I6 is also known,
with a dimeric structure containing four-coordinate In), dissolve
readily in weak donor solvents, and form adducts with neutral and
anionic ligands drawn from Groups 15, 16 and 17.1–3 Surprisingly
little is known about adducts with the simple neutral Group 16
ligands, thioethers,4–6 and there are no reports of seleno- or telluro-
ether complexes of indium. Hygroscopic complexes with Me2S and
Et2S, of composition [InX3(R2S)2], are believed to be trans trigo-
nal bipyramidal monomers,4,5 like the corresponding phosphane
adducts,2,3 and there is some evidence for 1:1 and 1:3 complexes
with InI3.4 The thiamacrocycle complex [InCl3([9]aneS3)] has been
prepared,6 although characterised only by microanalytical data.
There are no examples of thallium(III) halide complexes with
chalcogenoethers.1,2 We recently reported a detailed study of
gallium(III) halide thio-, seleno- and telluro-ether adducts, all of
which are based upon four-coordinate gallium centres (GaX3E,
E = S, Se or Te)7 and we describe below systematic studies of the
Experimental
Infrared spectra were recorded as Nujol mulls between CsI plates
using a Perkin-Elmer 983G spectrometer over the range 4000–
200 cm-1. Raman spectra were obtained using a Perkin-Elmer
FT2000R with a Nd:YAG laser. Significant bands in the range
350–180 cm-1 are listed below and bands believed due to [InX4]-
are marked with an asterisk. 1H NMR spectra were recorded
using a Bruker AV300 spectrometer. 77Se{ H} and 125Te{ H}
and 115In NMR spectra were recorded using a Bruker DPX400
spectrometer and were referenced to external neat Me2Se, Me2Te
and aqueous [In(H2O)6]3+ at pH = 1 respectively. Microanalyses
were undertaken by the University of Strathclyde microanalytical
service or Medac Ltd. Solvents were dried prior to use and all
preparations were undertaken using standard Schlenk techniques
under a N2 atmosphere. Anhydrous indium(III) halides (Aldrich
or Strem) were used as received. Me2S and Me2Se (Aldrich) were
stored over molecular sieves. [9]aneS3, [12]aneS4 and [14]aneS4
were also obtained from Aldrich and pumped in vacuo prior to
use. Other thio- seleno- and telluro-ethers were made by literature
methods8–12 and stored under dinitrogen over molecular sieves.
Anhydrous TlCl3 in MeCN solution was made by bubbling dry
chlorine through a stirred suspension of TlCl in dry MeCN, when
1
1
aSchool of Chemistry, University of Southampton, Southampton, UK SO17
1BJ
bDepartment of Pure and Applied Chemistry, M. D. S. University, Ajmer,
305009, India
† CCDC reference numbers 702284–702289. For crystallographic data in
CIF or other electronic format see DOI: 10.1039/b816148h
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the white powder rapidly dissolved to give a yellow solution. The
solution was purged with a slow stream of dry dinitrogen for
30 min to remove excess chlorine (leaving a colourless solution)
and aliquots of the solution used directly for the reactions.
Safety note—dimethyltelluride is toxic and volatile and should
therefore be handled with care in a suitably vented fume cupboard,
and residues destroyed appropriately.
CD2Cl2, 295 K): 2.25 (s, [3H], Me), 4.05 (s, [2H], CH2), 7.3–7.5 (m,
[2H], C6H4). IR (cm-1, Nujol): 314(m), 305(m), 245(m). Raman
(cm-1): 316(s), 304(m), 279(w) 237(m).
[InCl3{MeC(CH2SMe)3}]
InCl3 (0.21 g, 0.93 mmol) was suspended in CH2Cl2 (7 mL)
and MeC(CH2SMe)3 (0.19 g, 0.90 mmol) in CH2Cl2 was added
dropwise with constant stirring. The solution became clear and
after ~5 min a white solid began to precipitate. The solution was
stirred for 45 min and the solid was filtered off and dried in vacuo.
Yield: 0.29 g, 75%. Required for C8H18Cl3InS3·2CH2Cl2 (601.5):
[(InCl3)2{MeS(CH2)2SMe}2]
InCl3 (0.22 g, 1.0 mmol) was suspended in CH2Cl2 (7 mL) and
MeS(CH2)2SMe (0.13 g, 1.1 mmol) was added dropwise with
constant stirring. A white solid precipitated out within 5 min,
and the solution was stirred for a further 1 h. The precipitate was
filtered off and dried in vacuo. Yield: 0.19 g, 56%. Required for
C8H20Cl6In2S4 (686.9): C, 14.0; H, 2.9. Found: C, 14.6, H, 2.9%.
1H NMR (300 MHz, CD2Cl2, 295 K): 2.37 (s, [3H], Me), 3.07 (s,
[2H], CH2); (195K): 2.28, 2.43, 2.53 (Me), 3.04–3.20 (br, CH2). IR
(cm-1, Nujol): 309(m), 291(br,s), 245(w). Raman (cm-1): 302(vs),
268(m), 256(w).
1
C, 19.7; H, 3.7. Found: C, 19.7; H, 3.8%. H NMR (300 MHz,
CD2Cl2, 295 K): 1.18 (s, [3H], CMe), 2.33 (s, [9H], Me), 2.87
(s, [6H] CH2). IR (cm-1, Nujol): 281(br,s). Raman (cm-1): 295(s),
276(m), 260(m), 238(m).
[InCl3([9]aneS3)]
InCl3 (0.225 g, 1.01 mmol) was suspended in CH2Cl2 (7 mL), and
a solution of [9]aneS3 (0.18 g, 1.0 mmol) in CH2Cl2 (5 mL) was
added dropwise with constant stirring. The clear solution began to
deposit a white solid after a few minutes. The solution was stirred
for ~1 h, and the white solid was filtered off and dried in vacuo.
Yield: 0.25 g, 62%. IR (cm-1, Nujol): 292(vbr). Raman (cm-1): 292
(s), 278(s).
[InBr2{MeS(CH2)2SMe}2][InBr4]
This compound was made similarly to the chloro-complex. White
crystals. Yield: 58% Required for C8H20Br6In2S4 (953.6): C, 10.1;
1
H, 2.1. Found: C, 10.0; H, 1.9%. H NMR (300 MHz, CD2Cl2,
295 K): 2.54 (s, [3H], Me), 3.29 (s, [2H], CH2); (195 K): 2.32, 2.37,
2.42, 2.48, 2.58 (Me), 3.00, 3.07, 3.35, 3.60 (br, CH2). IR (cm-1,
Nujol): 271(w), 236(s)*, 226(m), 218 (m). Raman (cm-1): 261(m),
237(m)*, 197(s)*.
[InCl2([12]aneS4)][InCl4]
InCl3 (0.22 g, 1.0 mmol) was dissolved in CH2Cl2 (7 mL) and
[12]aneS4 (0.12 g, 0.50 mmol) in CH2Cl2 (7 mL) was added to
it dropwise with constant stirring. Within 5 min a white solid
precipitated out, and after 1 h the solid was filtered off and dried
in vacuo. Yield: 0.25 g, 73%. IR (cm-1, Nujol): 333(s)*, 318(m),
290(w). Raman (cm-1): 333(m)*, 320(s)*, 295(m), 278(s), 259(s).
i
[InCl2{ PrS(CH2)2SiPr}2][InCl4]
InCl3 (0.22 g, 1.0 mmol) was suspended in CH2Cl2 (7 mL) and
iPrS(CH2)2SiPr (0.18 g, 1.0 mmol) was added dropwise with
constant stirring and stirring was continued for 1 h. The clear
solution deposited colourless crystals after cooling for 2 d in a
freezer (-18 ◦C). These were filtered off and dried in vacuo. Yield:
0.24 g, 60%. Required for C16H36Cl6In2S4 (799.0): C, 24.0; H, 4.5.
[InCl2([14]aneS4)][InCl4]
InCl3 (0.22 g, 1.0 mmol) was dissolved in CH2Cl2 (7 mL) and
[14]aneS4 (0.13 g, 0.50 mmol) in CH2Cl2 (7 mL) was added to
it dropwise with constant stirring. Within 5 min a white solid
precipitated out. After 1 h the solid was filtered off and dried
in vacuo. Yield: 0.21 g, 58%. Required for C10H20Cl6In2S4 (710.9):
C, 16.9; H, 2.8. Found: C, 17.1; H, 3.2%. IR (cm-1, Nujol): 332(s)*,
320(sh), 300(w), 272(s). Raman (cm-1): 342(w)*, 325(m)*, 310(s),
303(s), 277(s), 259(s).
1
Found: C, 23.4; H, 4.3%. H NMR (300 MHz, CD2Cl2, 295 K):
3
1.41 (d, [6H] Me, J = 7 Hz) 3.2 (s, [2H], CH2), 3.56 (septet,
[H], CH, 3J = 7 Hz). IR (cm-1, Nujol): 333(vs)*, 316(w), 276(m),
246(m). Raman (cm-1): 369(w), 340(sh)*, 319(s)*, 287(w), 267(s).
i
[InBr2{ PrS(CH2)2SiPr}2][InBr4]
Was made similarly to the chloro-analogue above. White crystals.
Yield: 74%. Required for C16H36Br6In2S4 (1064.8): C, 18.0; H, 3.4.
1
[(InCl3)2{MeSe(CH2)2SeMe}2]
Found: C, 18.0; H, 3.1%. H NMR (300 MHz, CD2Cl2, 295 K):
3
1.41 (d, [6H], Me, J = 7 Hz), 3.15 (s, [2H], CH2), 3.51 (m, [H],
InCl3 (0.22 g, 1.0 mmol) was dissolved in CH2Cl2 (7 mL), and
MeSe(CH2)2SeMe (0.22 g, 1.00 mmol) was added dropwise with
constant stirring. The whole solution became greenish yellow and
a solid began to separate out. The solution was stirred for 1 h,
then the solid was filtered off and dried in vacuo. Pale yellow solid.
Yield: 0.29 g, 65%. Required for C8H20Cl6In2Se4 (874.5): C, 11.0; H,
2.3. Found: C, 9.8; H, 2.3% (reproducible spectroscopic data were
obtained from different samples, and the structure determined
crystallographically, however the %C observed for three samples
was consistently ~1% low). 1H NMR (300 MHz, CD2Cl2, 295 K):
2.48 (s, [3H], Me), 3.24 (s, [2H], CH2); (195 K): 2.26, 2.34, 2.45, 2.47
CH). IR (cm-1, Nujol): 235(m)*, 217(w), 205(m). Raman (cm-1):
234(s)*, 196(s)*.
[(InCl3)2{l2-o-C6H4(CH2SMe)2}]
InCl3 (0.22 g, 1.0 mmol) was dissolved in CH2Cl2 (7 mL) and
o-C6H4(CH2SMe)2 (0.10 g, 0.5 mmol) in CH2Cl2 was added
dropwise with constant stirring. The reaction mixture was stirred
for 12 h, and the white precipitate formed was filtered off and dried
in vacuo. Yield: 0.24 g, 76%. Required for C10H14Cl6In2S2 (640.7):
1
C, 18.8; H, 2.2. Found: C, 18.5; H, 2.8%. H NMR (300 MHz,
1612 | Dalton Trans., 2009, 1611–1619
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(Me), 2.82, 3.00, 3.15, 3.36 (br, CH2). IR (cm-1, Nujol): 300(m),
280(m), 247(m). Raman (cm-1): 298(s), 278(m), 250(m).
1
CD2Cl2, 295 K): 2.25 (s). 77Se{ H} NMR (295 K): -15.2. IR (cm-1,
Nujol): 240(w), 228(w), 210(m). Raman (cm-1): 240(w), 195(s).
[InCl3(Me2Te)2]
[InBr2{MeSe(CH2)2SeMe}2][InBr4]
Me2Te (0.31 g, 2.0 mmol) was dissolved in CH2Cl2 and added
dropwise to a suspension of InCl3 (0.22 g, 1.00 mmol) in CH2Cl2
(~7 mL) with constant stirring. A clear yellow solution was
produced. After 15 min the solution was concentrated in vacuo,
when a light yellow solid was deposited. This was filtered off and
dried in vacuo. Yield: 0.34 g, 63%. Required for C4H12Cl3InTe2
(536.5): C, 8.9; H, 2.3. Found: C, 8.4; H, 2.3%. 1H NMR (300 MHz,
This compound was made similarly to the chloro-complex from
InBr3. Pale yellow solid. Yield: 78%. Required for C8H20Br6In2Se4
(1141.1): C, 8.4; H, 1.8. Found: C, 8.0; H, 1.8%. 1H NMR
(300 MHz, CD2Cl2, 295 K): 2.35 (s, [3H], Me), 3.25 (s, [2H],
CH2); (195 K): 2.27, 2.34, 2.40 (Me), 3.01, 3.57 (m, CH2). IR
(cm-1, Nujol): 238(m)*, 223(m), 202(m), 197(m). Raman (cm-1):
242(m)*, 227(m), 197(s)*.
1
CD2Cl2, 295 K): 2.16 (s). 125Te{ H} NMR (295 K): no resonance
observed; 190 K: +23.7, +84.4. IR (cm-1, Nujol): 280(m), 255(s),
212(m).
InI3{MeSe(CH2)2SeMe}
This compound was made similarly to the chloro-complex from
InI3. Yellow solid. Yield: 50%. Required for C4H10I3InSe2 (711.6):
[InBr3(Me2Te)]
1
C, 6.8; H, 1.4. Found: C, 6.6; H, 1.4%. H NMR (300 MHz,
Prepared similarly to the chloro analogue above. Yellow/brown
solid. Yield: 59%. Required for C2H6Br3InTe (512.2): C, 4.7; H,
1.2. Found: C, 4.5; H, 1.3%. 1H NMR (300 MHz, CD2Cl2, 295 K):
CD2Cl2, 295 K): 2.47 (s, [3H], Me), 3.36 (s, [2H], CH2). IR (cm-1,
Nujol): 255(w), 247(w), 213(m), 202(m). Raman (cm-1): 258(w),
236(w), 196(w).
1
2.17 (s). 125Te{ H} NMR: no resonance observed between 295 K
and 200 K. IR (cm-1, Nujol): 238(m), 230(sh), 209(m), 202(m).
n
[(InCl3)2{ BuSe(CH2)2SenBu}2]
[InI3(Me2Te)]
InCl3 (0.22 g, 1.00 mmol) was suspended in CH2Cl2 (7 mL),
nBuSe(CH2)2SenBu (0.29 g, 0.99 mmol) was added to it dropwise
with constant stirring. The solution became greenish yellow. The
solution was stirred for 1 h then kept in freezer for 2 d when
yellow crystals were obtained. Yield: 0.23 g, 45%. Required for
C20H44Cl6In2Se4 (1042.8): C, 23.0; H, 4.3. Found: C, 22.3; H, 4.4%.
1H NMR (300 MHz, CD2Cl2, 295 K): 1.00 (t, [3H], Me), 1.48 (m,
[2H], CH2), 1.82 (m, [2H], CH2), 3.08 (t, [2H], SeCH2), 3.33 (s,
Prepared similarly to the chloro analogue above. Orange solid.
Yield: 47%. Required for C2H6I3InTe (653.2): C, 3.7; H, 1.0.
1
Found: C, 3.3; H, 1.0%. H NMR (300 MHz, CD2Cl2, 295 K):
1
2.29 (s). 125Te{ H} NMR: no resonance observed between 295 K
and 200 K. IR (cm-1, Nujol): 235(m), 226(sh), 197(m).
[(InCl3)2{l2-MeTe(CH2)3TeMe}]
1
[2H], SeCH2). 77Se{ H} NMR (295 K): 117.6. IR (cm-1, Nujol):
305(sh), 295(br, s), 237(w). Raman (cm-1): 297(s), 247(w).
MeTe(CH2)3TeMe (0.34 g, 1.00 mmol) was dissolved in CH2Cl2
and added dropwise to a solution of InCl3 (0.22 g, 1.00 mmol) in
CH2Cl2 (~7 mL) with constant stirring. A clear yellow solution was
produced and after ~15 min an orange solid began to separate out.
After stirring for 1 h the solid was filtered off and dried in vacuo.
Orange solid. Yield: 0.35 g, 91%. Required for C5H12Cl6In2Te2
(769.7): C, 7.8; H, 1.6. Found: C, 7.1; H, 1.8%. 1H NMR (CD2Cl2,
295 K): 1.91 (s) [3H] CH3, 2.12 (m) [H] CH2, 2.69 (t) [2H] CH2Te.
IR (cm-1, Nujol): 310(w), 297(s), 273(m), 241(m). Raman: 313(m),
272(s).
[InCl3(Me2Se)]
InCl3 (0.22 g, 1.0 mmol) was suspended in CH2Cl2 (7 mL) and
Me2Se (0.33 g, 3.0 mmol) was added to it dropwise with constant
stirring. A clear solution was produced; after 15 min the solution
was concentrated in vacuo, when a white solid was deposited. This
was filtered off and dried in vacuo. Yield: 0.17 g, 53%. Required
for C2H6Cl3InSe·1/2CH2Cl2 (372.6): C, 8.1; H, 1.9. Found: C, 8.3;
1
H, 2.3%. 1H NMR (300 MHz, CD2Cl2, 295 K): 2.38 (s). 77Se{ H}
NMR (295 K): +24.1. IR (cm-1, Nujol): 311(sh), 290(sh), 272(m),
235(m), 218(m). Raman (cm-1): 309(m), 293(m), 244(s), 198(m).
X-Ray crystallography†
Details of the crystallographic data collection and refinement
parameters are given in Table 1. Crystals were obtained by
cooling the CH2Cl2 filtrates from the reaction syntheses at ca.
-18 ◦C. Data collection used a Nonius Kappa CCD diffractometer
fitted with monochromated (graphite or confocal mirrors) Mo-
[InBr3(Me2Se)]
Was made from a 1:3 molar ratio of InBr3:Me2Se as above. Cream
solid. Yield: 57%. Required for C2H6Br3InSe (463.6): C, 5.2; H,
1.3. Found: C, 5.4; H, 2.0%. 1H NMR (300 MHz, CD2Cl2, 295 K):
˚
Ka X-radiation (l = 0.71073 A). Crystals were held at 120 K
1
2.45 (s). 77Se{ H} NMR (295 K): -6.0. IR (cm-1, Nujol): 239(s),
in a nitrogen gas stream. Structure solution and refinement
were generally routine,13,14 (except as described below) with
hydrogen atoms on C added to the model in calculated positions
and using the default C–H distance. The initial solution of
236(sh), 210(s). Raman (cm-1): 238(s), 210(s), 189(s).
[InI3(Me2Se)]
[InBr2{MeSe(CH2)2SeMe}2][InBr4] showed two large peaks (ca.
-3
˚
This compound was made from a 1:3 molar ratio of InI3:Me2Se as
above. Cream solid. Yield: 62%. Required for C2H6I3InSe (604.6):
C, 4.0; H, 1.0. Found: C, 4.1; H, 1.1%. H NMR (300 MHz,
6 and 10 e A ) in the difference electron-density map close to Se5
and Se7. These were interpreted as fractional Se atoms associated
with disorder of the In2 centred cation (see Fig. 4(b)) with sofs of
1
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Table 1 Crystal data and structure refinement detailsa
i
i
[In2Cl6{MeSe- [InCl2{ PrS(CH2)2SiPr}2]- [InBr2{ PrS(CH2)2- [InBr2{MeSe(CH2)2- [InCl2([14]-
Compound
(CH2)2SeMe}2] [InCl4]·0.5CH2Cl2
SiPr}2][InBr4]
SeMe}2][InBr4]
aneS4)][InCl4] [InBr3(SeMe2)]
Formula
M
C8H20Cl6In2Se4 C16.5H37Cl7In2S4
C16H36Br6In2S4
1065.79
Orthorhombic
P212121 (19)
11.4407(10)
12.9075(12)
21.6066(12)
90
90
90
3190.7(4)
4
9.226
2016
22267
7294
0.041
0.786, 1.000
262, 0
1.05
-0.58 to +0.60
0.028
C8H20Br6In2Se4
1141.18
C10H20Cl6In2S4 C2H6Br3InSe
874.42
Monoclinic
P21/n (14)
9.160(3)
12.463(4)
9.826(3)
90
841.49
Monoclinic
C2/c (15)
31.324(5)
11.033(2)
20.679(3)
90
710.84
463.58
Orthorhombic
Pnma (62)
13.449(5)
10.233(3)
6.787(2)
90
90
90
934.0(5)
4
Crystal system
Space group (no.)
Triclinic
Triclinic
¯
¯
P1 (2)
P1 (2)
˚
a/A
7.6920(10)
16.323(2)
20.058(3)
86.925(6)
86.862(10)
86.979(10)
2507.9(6)
4
17.195
2048
35035
11355
11.758(5)
12.416(5)
15.640(7)
92.10(2)
90.46(2)
93.36(2)
2277.8(16)
4
˚
b/A
˚
c/A
a/◦
b/◦
g /◦
U/A
Z
97.00(2)
90
118.131(7)
90
3
˚
1113.4(5)
2
9.318
6302.5(18)
8
2.329
m(Mo-Ka)/mm-1
F(000)
3.088
1376
19.172
824
808
14702
3336
30172
Total no. reflections
Unique reflections
Rint
36707
8916
6608
1126
2550
0.042
7202
0.084
0.059
0.102
0.688, 1.000
396, 7
0.057
0.451, 1.000
38, 0
Min., max. transmission
0.600, 0.746
0.669, 1.000
275, 0
0.634, 1.000
393, 17
1.13
-1.69 to +3.22
0.068
0.108
0.115
0.131
No. of parameters, restraints 93, 0
Goodness-of-fit on F2
1.10
1.14
1.12
1.07
-3
˚
Resid. electron density/e A -1.02 to +1.33 -1.10 to +1.22
-1.21 to +1.64 -1.52 to +1.05
b
R1 [Io > 2s(Io)]
R1 (all data)
0.029
0.036
0.057
0.060
0.067
0.105
0.119
0.136
0.090
0.142
0.185
0.203
0.035
0.048
0.070
0.075
0.034
0.046
0.048
b
wR2 [Io > 2s(Io)]
wR2 (all data)
ꢀ
ꢀ
ꢀ
◦
a
2
Common items: temperature = 120 K; wavelength (Mo-Ka) = 0.71073 A; q(max) = 27.5 . b R1
=
ꢀFo| - |Fcꢀ/ |Fo|. wR2 = [ w(Fo
-
˚
ꢀ
Fc2)2/ wFo
] .
4
1/2
0.28 (Se5b) and 0.14 (Se7b). The Me C atoms associated with these
fractional Se atoms were identified and using DFIX commands
allowed refinement to converge with an improved fit to the data
over the non-disordered model. [InCl2([14]aneS4)][InCl4] with two
molecules in the asymmetric unit showed disorder at C18 and
C19 in the In2 centred cation as evidenced by very elongated adp
ellipsoids. This was modelled using two sites at each atom (A
and B) using isotropic C atoms and several DFIX commands to
maintain sensible bond lengths. Selected bond lengths and angles
are given in Tables 2 to 7.
Results and discussion
Fig. 1 Structure of centrosymmetric [In2Cl6{MeSe(CH2)2SeMe}2] show-
ing the atom labelling scheme. H atoms are omitted for clarity and
displacement ellipsoids are shown at the 50% probability level. Symmetry
operation: a = -x, -y, 1 - z.
Dithio- and diseleno-ethers
Indium(III) halides InX3 (X = Cl, Br or I) react with equimolar
ratios of the dithioethers MeS(CH2)2SMe or iPrS(CH2)2SiPr
or the diselenoethers MeSe(CH2)2SeMe or nBuSe(CH2)2SenBu
(L–L) to afford complexes with a 1:1 InX3:L–L stoichiometry
based upon their microanalytical data. This contrasts with the
gallium(III) halides which form exclusively [(GaX3)2(m2-L–L)].7
Given the lability of the In(III) species in solution (vide infra), it
is appropriate to discuss the structural data first. X-ray crystal
structures were determined for several of the new complexes—the
structure types are summarised in Scheme 1. For the bidentate
ligand complexes all of the structures show six-coordinate indium
centres, the structures belonging to one of two types, the halide-
bridged [InX2(L–L)(m-X)2InX2(L–L)] or ionic [InX2(L–L)2][InX4]
(Tables 2–5, Fig. 1–4). The neutral dimer structural type is
exemplified by [(InCl3)2{MeSe(CH2)2SeMe}2] (Fig. 1, Table 2),
which is a centrosymmetric molecule with each indium bonded to
one chelating diselenoether in the DL form, two terminal and two
bridging chlorines. The bond lengths are consistent with a trans
influence Cl > Se and this is reflected in the asymmetric In–Clbridge
˚
˚
distances 2.5447(8) A (trans Se) and 2.6633(12) A (trans Cl). The
smallest angle about the indium is Se–In–Se of 79.89(2)◦ and the
largest involves the terminal chlorines Cl–In–Cl 98.99(4)◦. The
structure of [(InCl3)2{ BuSe(CH2)2SenBu}2] was also determined
n
and exhibits a very similar heavy atom core.‡ However, there was
n
‡ [(InCl3)2{ BuSe(CH2)2SenBu}2]·nCH2Cl2: Monoclinic, P21/c (14), a =
˚
13.738(3), b = 20.315(5), c = 7.7387(15) A, a = 90.0, b = 105.042(15), g =
◦
3
˚
90.0 , V = 2085.8(8) A , Z = 2, T = 120 K, R1 = 0.086.
1614 | Dalton Trans., 2009, 1611–1619
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Scheme 1 Structure types identified crystallographically.
◦
˚
Table 2 Selected bond lengths (A) and angles ( ) for [In2Cl6{MeSe-
(CH2)2SeMe}2]
In1–Cl1
In1–Cl2
In1–Se1
2.5447(12)
2.4124(12)
2.7926(8)
98.99(4)
91.57(3)
84.07(3)
95.93(3)
88.80(3)
92.26(4)
87.89(2)
In1–Cl3
In1–Cl1a
In1–Se2
2.4466(12)
2.6633(12)
2.7339(8)
97.52(4)
87.80(4)
79.89(2)
93.10(3)
80.60(3)
95.26(3)
172.38(3)
167.07(3)
Cl2–In1–Cl3
Cl3–In1–Cl1
Cl1–In1–Cl1a
In1–Cl1–In1a
Cl1–In1–Se2
Cl2–In1–Se1
Cl1a–In1–Se1
Cl2–In1–Se2
Cl2–In1–Cl1
Cl2–In1–Cl1a
Se2–In1–Se1
Cl3–In1–Se2
Cl1a–In1–Se2
Cl3–In1–Se1
Cl3–In1–Cl1a
Cl1–In1–Se1
166.16(3)
Symmetry operation: a =-x,-y, 1 - z.
significant disorder in the n-butyl chains and hence the structure
is not discussed in detail.
i
Fig.
2
Structure of the cation in trans-[InCl2{ PrS(CH2)2SiPr}2]-
i
The ionic type is exemplified by trans-[InCl2{ PrS(CH2)2-
[InCl4]·0.5CH2Cl2 showing the atom labelling scheme. H atoms are omitted
for clarity and displacement ellipsoids are shown at the 50% probability
level.
SiPr}2][InCl4], trans-[InBr2{ PrS(CH2)2SiPr}2][InBr4] and trans-
i
[InBr2{MeSe(CH2)2SeMe}2][InBr4]. In the first, (Table 3,
Fig. 2) the chelating dithioethers are again DL stereoiso-
mers and the In–Cl distances little different from those in
[(InCl3)2{MeSe(CH2)2SeMe}2] despite the cationic form. The
diselenoethers with DL conformations. The second cation shows
some disorder which was satisfactorily modelled as a mixture of
DL and meso forms of the diselenoethers. The data in Table 5
and the discussion below refer to the disorder-free cation. The
angles within the chelate rings <Se–In–Se are 86.35(5)◦ and
87.10(5)◦, and the <Br–In–Se fall into two groups, those with the
(Se)–Me group on the same side of the Se4In plane as the bromine
are somewhat greater than 90◦ (93.28(5)–96.28(5)◦), whereas when
the (Se)Me is on the opposite side of the plane the angles are
smaller (83.53(5)–86.54(5)◦). The d(In–Br) are slightly longer
˚
In–Cl distances 2.4237(18), 2.4393(18) A are significantly shorter
˚
than In–S 2.645(2)–2.696(2) A, despite the similar covalent
radii of S and Cl, which shows that, as in other gallium(III)
and indium(III) complexes with Groups 15 or 16 ligands, the
In–halogen bond is the dominant interaction, with weaker
bonding to the neutral donor completing the coordination
sphere.7,15,16 The trans-[InBr2{ PrS(CH2)2SiPr}2][InBr4] also con-
i
tains two chelating dithioethers in the DL conformation (Table 4,
Fig. 3), with the In–S distances little different (2.6518(10)–
+
˚
˚
2.6901(11) A) to the chloride analogue. The structural data on
(2.6076(15), 2.6113(15) A) in trans-[InBr2{MeSe(CH2)2SeMe}2]
i
i
+
˚
trans-[InBr2{MeSe(CH2)2SeMe}2][InBr4] are more complicated.
There are two cations in the unit cell, one of which (Fig. 4a) shows
a six-coordinate In centre with trans bromines and two chelating
than in trans-[InBr2{ PrS(CH2)2S Pr}2] (2.5775(5), 2.5718(5) A).
Given that the neutral dimer and the [cation][anion] crystals
examined were isolated from the same solvent under similar
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◦
i
˚
Table 3 Selected bond lengths (A) and angles ( ) for [InCl2{ PrS-
(CH2)2SiPr}2][InCl4]·0.5CH2Cl2
In1–Cl1
In1–S1
In1–S3
2.4237(18)
2.645(2)
2.677(2)
In1–Cl2
In1–S2
In1–S4
Cl1–In1–S1
Cl1–In1–S2
Cl1–In1–S3
Cl1–In1–S4
S1–In1–S3
S2–In1–S3
S2–In1–S4
2.4393(18)
2.669(2)
2.696(2)
95.63(6)
85.31(6)
87.80(6)
94.07(6)
94.11(6)
172.91(6)
98.68(6)
Cl1–In1–Cl2
Cl2–In1–S1
Cl2–In1–S2
Cl2–In1–S3
Cl2–In1–S4
S1–In1–S2
S3–In1–S4
S1–In1–S4
178.57(7)
84.12(6)
93.27(6)
93.62(6)
86.25(6)
84.92(6)
83.46(6)
169.91(6)
◦
i
˚
Table 4 Selected bond lengths (A) and angles ( ) for [InBr2{ PrS-
(CH2)2SiPr}2][InBr4]
i
Fig. 3 Structure of the cation in trans-[InBr2{ PrS(CH2)2SiPr}2][InBr4]
showing the atom labelling scheme. H atoms are omitted for clarity and
displacement ellipsoids are shown at the 50% probability level.
In1–Br2
In1–S1
In1–S3
Br2–In1–Br1
Br2–In1–S4
Br2–In1–S3
S1–In1–S3
Br2–In1–S2
S1–In1–S2
Br1–In1–S1
2.5775(5)
2.6518(10)
2.6852(11)
178.653(19)
95.34(2)
86.53(3)
94.08(4)
85.52(2)
84.69(3)
84.16(2)
In1–Br1
In1–S4
In1–S2
Br2–In1–S1
Br1–In1–S4
Br1–In1–S3
S4–In1–S3
Br1–In1–S2
S4–In1–S2
2.5918(5)
2.6775(11)
2.6901(11)
96.60(2)
83.95(2)
94.53(3)
83.96(3)
93.45(2)
98.93(3)
◦
˚
Table 5 Selected bond lengths (A) and angles ( ) for [InBr2{MeSe-
(CH2)2SeMe}2][InBr4]a
In1–Br1
In1–Se1
In1–Se2
Br1–In1–Br2
Br2–In1–Se1
Br2–In1–Se3
Br2–In1–Se4
Br2–In1–Se2
Se1–In1–Se2
Se3–In1–Se4
2.6076(15)
2.7370(16)
2.7802(15)
In1–Br2
In1–Se3
In1–Se4
Br1–In1–Se1
Br1–In1–Se3
Br1–In1–Se4
Br1–In1–Se2
Se1–In1–Se4
Se3–In1–Se2
2.6113(15)
2.7516(16)
2.7762(15)
85.22(5)
94.98(5)
86.54(5)
95.03(5)
93.79(5)
92.75(5)
178.50(6)
96.28(5)
83.53(5)
93.28(5)
85.15(5)
86.35(5)
87.10(5)
a Values refer to the In1 centred cation which shows no evidence for
disorder.
anions show one IR active stretch (u3, t2) and two Raman active
stretches (u3, t2 and u1, a1). Literature values17 (cm-1) are: X =
Cl u1 = 321, u3 = 337; X = Br u1 = 197, u3 = 239; X = I
u1 = 139, u3 = 185. The characteristic vibrations of the [InX4]-
anions were clearly present in the spectra of powdered trans-
[InCl2{ PrS(CH2)2SiPr}2][InCl4], trans-[InBr2{ PrS(CH2)2SiPr}2]-
[InBr4] and trans-[InBr2{MeSe(CH2)2SeMe}2][InBr4] (see Experi-
mental section, marked *), but absent from those of
[InCl2(L–L)(m-Cl)2InCl2(L–L)] (L–L = MeSe(CH2)2SeMe or
nBuSe(CH2)2SenBu), showing the bulk samples do indeed contain
the same indium environments as the crystals examined. On the
basis of its vibrational spectrum, [InBr2{MeS(CH2)2SMe}2][InBr4]
was also identified as containing the ionic form. The complex
InI3{MeSe(CH2)2SeMe} was isolated, but the very low frequency
of the [InI4]- vibrations, which fall below the spectrometer ranges,
made it impossible to identify the form present in the absence of
crystallographic data.
i
i
Fig.
4
Structure of the cations in trans-[InBr2{MeSe(CH2)2-
SeMe}2][InBr4]. (a) The In1 centred non-disordered cation. (b) The In2
disordered cation showing the disorder at Se5 and Se7 (and the associated
Me groups). The disorder is modelled using two sites with Se5b and Se7b
the smaller components. H atoms are omitted for clarity and displacement
ellipsoids are shown at the 50% probability level.
conditions (although only one form was identified crystallograph-
ically for each ligand/InX3 combination), two questions arise—
are the structures described above characteristic of the bulk
sample, and are the same structural units retained in solution?
The first question was addressed by careful examination of the
far-IR and Raman spectra of the bulk solids. Tetrahedral [InX4]-
The solution speciation is less easily confirmed. Generally
the complexes are poorly soluble in chlorocarbons, and it is
necessary to avoid donor solvents which would compete with the
1616 | Dalton Trans., 2009, 1611–1619
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1
◦
˚
Group 16 ligand. The H NMR spectra of all the complexes in
Table 6 Selected bond lengths (A) and angles ( ) for [InCl2([14]-
aneS4)][InCl4]a
CD2Cl2 solution at ambient temperatures show simple patterns,
the observed resonances showing small shifts to high frequency
from those in the “free” ligands, consistent with exchanging
systems. Fast exchange on the NMR timescale persists to low
temperatures, but at very low temperatures (~200 K) the reso-
nances split, consistent with the presence of a number of ligand
environments (although lines remain broad in some cases and the
low temperature limiting spectra are not obtained). For example,
at 195 K the spectrum of [InBr2{MeS(CH2)2SMe}2][InBr4] shows
five d(Me) resonances (2.32–2.58 ppm) of very disparate inten-
sities and associated methylene multiplets. The other complexes
show broadly similar spectra at low temperatures (Experimental
section). Slow pyramidal inversion at sulfur/selenium would give
rise to a number of isomers, whilst the presence of [InX2(L–
L)(m-X)2InX2(L–L)] and possibly five-coordinate [InCl3(L–L)]
would add further NMR distinguishable forms. However, there
is insufficient information in the experimental data to identify the
forms present at low temperatures. Due to the poor solubility,
77Se NMR spectra were difficult to obtain even at ambient
temperatures, and provide little information due to the fast
exchange processes. Similarly, the 115In nucleus, whilst inherently
very sensitive, has a moderately large quadrupole moment [115In,
95.7%, I = 9/2, N = 21.914 MHz, Q = 1.16 ¥ 10-28 m2, Dc =
1890].16,18 In practice we found that resonances due to tetrahedral
[InX4]- were readily observable, however no resonances due to
other In species were evident due to the low symmetry environment
and the associated fast quadrupolar relaxation. Conductivity
measurements on representative examples in CH2Cl2 solution
(10-3 mol dm-3) gave values greater than non-electrolytes, but
much lower than those expected for 1:1 electrolytes. It seems likely
that in solution in non-coordinating solvents, mixtures of indium
species which are undergoing rapid ligand exchange are present,
but the systems are not well suited to further investigation of
this speciation. On this basis, the form which crystallises out as
the solid may well reflect the least soluble one under particular
conditions.
In1–Cl1
In1–S1
In1–S3
Cl1–In1–Cl2
Cl1–In1–S4
Cl1–In1–S2
Cl1–In1–S3
S2–In1–S1
S3–In1–S1
2.418(4)
2.725(4)
2.681(4)
98.17(15)
95.28(15)
94.25(15)
90.29(14)
79.63(13)
84.65(13)
In1–Cl2
In1–S2
In1–S4
Cl2–In1–S4
Cl2–In1–S2
Cl2–In1–S1
S2–In1–S3
S4–In1–S1
S4–In1–S3
2.406(4)
2.626(4)
2.610(4)
97.30(14)
94.86(13)
87.26(14)
87.62(13)
89.56(14)
78.67(13)
a Values refer to the In1 centred cation which shows no evidence for
disorder. The second cation, which does show evidence for disorder at
two adjacent methylene groups, has a similar geometry around In2.
of [InCl3([9]aneS3)], leads to a provisional assignment of a fac
geometry here also.
More interesting were the tetrathiamacrocycles [12]aneS4 and
[14]aneS4. Based upon literature data we anticipated that the
relatively small hole-sizes available in these ligands may offer an
opportunity to generate the cis-[InCl2(L)]+ cations specifically. For
example, the cations [RhCl2([14]aneS4)]+ and [RhCl2([12]aneS4)]+
both adopt cis geometries,19 and comparison of the metal ion radii
gives r(Rh ) = 0.66 A and r(In ) = 0.80 A,20 therefore it is antic-
ipated that In(III) would be too large for the macrocycle binding
cavities available in the 12- and 14-membered rings. Reaction of
InCl3 with these macrocycles in anhydrous CH2Cl2 gave white
complexes with a 2(InCl3):thiamacrocycle stoichiometry. For the
[14]aneS4 complex, crystals obtained from the mother liquor
confirmed the constitution to be [InCl2([14]aneS4)][InCl4] (Table 6,
Fig. 5). There are two similar cations in the unit cell, although one
shows some disorder in the orientation of the methylene groups of
the macrocycle. The data in Table 6 refer to the well-defined cation,
although the core geometries are not significantly different. As can
be seen from Fig. 5, the cation does indeed adopt a cis geometry
with the macrocycle in a folded conformation (contrasting with the
trans forms found with the bidentates). The octahedron is distorted
III
III
˚
˚
The bulky dithioether o-C6H4(CH2SMe)2 forms a white complex
with InCl3 which on the basis of the IR and Raman spectra and mi-
croanalysis is formulated as the ligand-bridged dimer, [(InCl3)2{m2-
o-C6H4(CH2SMe)2}], with distorted tetrahedral SCl3 coordina-
tion. The dimer formation parallels that observed with GaCl3,7
and may reflect the steric constraints of the o-xylyl backbone in this
ligand. The diselenoether o-C6H4(CH2SeMe)2, initially produces a
white complex with InCl3, but this decomposed in solution to form
the selenonium salt [o-C6H4CH2Se(Me)CH2][InCl4], identified by
the 77Se NMR shift of d = +384 and ions in the ES+ and ES- mass
spectra centred at m/z = 199 and 257 due to cation and anion
respectively. A similar fragmentation occurred on reaction of this
ligand with GaCl3 and the selenonium cation was identified by a
crystal structure in that case.7
Thiamacrocycles. The known [InCl3([9]aneS3)]6 was re-
prepared, but proved to be insoluble in non-coordinating solvents,
which prevented attempts to grow crystals for X-ray study.
However, there seems little doubt it has a fac octahedral structure
(S3Cl3). The complex [InCl3{MeC(CH2SMe)3}], containing the
tripodal tridentate thioether, was also isolated, and the similarity
of the In–Cl vibrations in the Raman/far-IR spectra to those
Fig. 5 Structure of the cation in [InCl2([14]aneS4)][InCl4]. There are two
cations in the asymmetric unit with the In2 centred species showing some
disorder in two of the methylene groups. The geometry around the In atom
is very similar in the two cations and the picture shows the In1 centred
cation with the atom labelling scheme. H atoms are omitted for clarity and
displacement ellipsoids are shown at the 50% probability level.
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◦
˚
[InX3(Me2Se)x] (x = 2 or 3) and/or ionic species. However, the data
are insufficient to permit specific assignments, and the resonances
broaden and are lost on warming above ~200 K. The isolation of
the four-coordinate complexes with Me2Se here contrast with the
five-coordination assigned to the R2S complexes previously.4,5
Table 7 Selected bond lengths (A) and angles ( ) for [InBr3(SeMe2)]
In1–Br1
In1–Br2
2.4901(12)
2.4981(7)
In1–Se1
Se1–C1
2.6455(11)
1.941(5)
Br1–In1–Br2
Br2–In1–Br2a
C1–Se1–C1a
110.92(2)
112.61(4)
96.3(3)
Br1–In1–Se1
Br2–In1–Se1
C1–Se1–In1
109.63(3)
106.26(2)
99.58(17)
Telluroethers. Treatment of InX3 with 2 mol. equivs. of Me2Te
in CH2Cl2 gives yellow through orange solids of stoichiometry
[InCl3(Me2Te)2] and [InX3(Me2Te)] (X = Br or I). IR spectra do
not show evidence for [InX4]-, and are consistent with neutral
five- or four-coordinate species (the compounds decomposed
in the laser beam hence no Raman spectra were obtained).
1H NMR spectra show singlet resonances shifted only very
slightly from that of Me2Te itself. Variable temperature 125Te
NMR spectra for [InCl3(Me2Te)2] show no resonances down to
223 K, consistent with a highly labile complex. However, at
190 K two singlet resonances are observed—comparison with
the Me2Se/InX3 systems suggests the high frequency resonance
(+84.4 ppm) may arise from the five-coordinate [InCl3(Me2Te)2],
while that at +23.7 ppm may be attributed to the four-coordinate
[InCl3(Me2Te)]. For [InX3(Me2Te)] (X = Br or I), no 125Te
NMR resonance was observed down to 200 K, and significant
precipitation of the complex was evident. Reaction a 1:1 mol. ratio
of InCl3 to MeTe(CH2)3TeMe unexpectedly gave a yellow solid of
composition [(InCl3)2{m2-MeTe(CH2)3TeMe}] which was poorly
soluble in chlorocarbons. IR and Raman spectra again rule out
[InCl4]-, leading to tentative formulation as a ligand-bridged dimer
with tetrahedral In(III). All the telluroether complexes appear to
be extensively dissociated in solution and the stoichiometries of
the isolated solids may reflect the least soluble species in each
system. All telluroether complexes decompose over a few weeks
even in the solid state.
Symmetry operation: a = x, 1/2 - y, z.
by the presence of five- and six-membered chelate rings in the
coordinated macrocycle, with the <S–In–S in the six-membered
rings some 10◦ wider than those in the five-membered ones, and
again the trans influence Cl > S is clearly evident with In–StransCl
=
˚
˚
2.725(4), 2.681(4) A against In–StransS = 2.610(4), 2.626(4) A. The
complex is too poorly soluble for solution studies, but the [InCl4]-
anions are clearly evident in the Raman spectrum of the solid. The
very similar far-IR and Raman spectra of [InCl2([12]aneS4)][InCl4]
led to a similar structural assignment.
[InX3(SeMe2)]. The reactions of InX3 with dimethylsulfide and
diethylsulfide to give the five-coordinate [InX3(R2S)2] have been
reported (vide supra).4,5 To provide a comparator monodentate
selenoether, we have examined the reactions of InX3 (X = Cl,
Br or I) with Me2Se in CH2Cl2 in a 1:3 molar ratio. However,
the cream solids isolated were identified by microanalysis as
the 1:1 complexes [InX3(Me2Se)], and this was confirmed by an
X-ray crystal study of the bromide, which revealed a distorted
˚
tetrahedral geometry (Table 7, Fig. 6). The In–Se = 2.6455(1) A
˚
˚
and In–Br = 2.4901(12), 2.4981(7) A are ca. 0.1 A shorter than
the corresponding bonds in trans-[InBr2{MeSe(CH2)2SeMe}2]+,
a consequence of the lower coordination number. The In–Br
distances compare well with those in the two [InBr4]- salts
˚
described above, which lie in the range 2.4780(15)–2.5135(17) A.
Thallium(III). Thallium(III) chloride reacts immediately with
The vibrational spectra are consistent with C3v geometry, showing
two In–X stretching vibrations, both of which are IR and Raman
active. The complexes are easily soluble in CH2Cl2 and each
exhibits a single 77Se NMR resonance, however the chemical shifts
vary considerably both with concentration and temperature.
Me2Se or Me2Te in anhydrous MeCN solution, with precipitation
1
1
of TlCl. The filtrates were examined by 77Se{ H} and 125Te{ H}
NMR spectroscopy; in both cases Me2ECl2 (E = Te: d = 775; E =
Se: d = 464) was the only significant product detected.21,22 There
appears to be no reaction between TlCl3 and Me2S in MeCN; in
1
situ 1H and 13C{ H} NMR spectra showed only “free” Me2S even
after two weeks and there was no evidence for the presence of
chlorination products such as MeSCH2Cl or Me2SCl2.23 Removal
of solvent and ligand in vacuo left a white solid which was identified
by IR spectroscopy as TlCl3. There appear to be no literature
reports of Tl(III) complexes with neutral heavier Group 15 or 16
donor ligands, and even for Tl(I) characterised chalcogenoether
complexes seem to be limited to thiamacrocycles24 and two very
labile diselenoether adducts of TlPF6.25
Conclusions
The results from this study show that unlike the corresponding
complexes with GaX3 (X = Cl, Br or I) which exclusively adopt
distorted tetrahedral X3E donor sets (E = S or Se), those with
indium(III) halides are much more structurally diverse. With
the dimethylene-linked bidentate chalcogenoethers chelation is
always observed, and the common coordination number is six.
Four-coordination is only observed for Me2E (E = Se or Te),
o-C6H4(CH2SMe)2 and MeTe(CH2)3TeMe. Some fragmentation
probably involving C–E bond scission is observed for the heavier
Fig. 6 Structure of [InBr3(SeMe2)] showing the atom labelling scheme. H
atoms are omitted for clarity and displacement ellipsoids are shown at the
50% probability level. Symmetry operation: a = x, 1/2 - y, z.
Addition of Me2Se to these solutions gives a single resonance,
the chemical shift of which varies with the amount of ligand
added, showing fast intermolecular exchange. At 190 K these
solutions show a number of selenium resonances to high frequency
of those of the 1:1 complexes, probably indicating the formation of
1618 | Dalton Trans., 2009, 1611–1619
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chalcogenoethers. For the chelating bidentates, two structure
types have been identified; neutral, halo-bridged dimers and
octahedral cations. Solution data suggest the complexes are in
dynamic equilibria, consistent with labile systems where the energy
differences between the different forms are rather small. Structural
data show that the In - X bonds are dominant, with much weaker
In - chalcogen interactions. These complexes are much more labile
in solution than the diphosphane and diarsane (L–L) complexes of
In(III) for which [InX2(L–L)2]+ and the halo-bridged [(InX3)2(L–
L)2] are also commonly observed. For the Group 15 ligand systems
several other structure types were also observed.16,26
8 F. R. Hartley, S. G. Murray, W. Levason, H. E. Soutter and C. A.
McAuliffe, Inorg. Chim. Acta, 1979, 35, 265.
9 D. J. Gulliver, E. G. Hope, W. Levason, S. G. Murray, D. M. Potter and
G. L. Marshall, J. Chem. Soc. Perkin Trans. II, 1984, 429.
10 T. Kemmitt, E. G. Hope and W. Levason, Organometallics, 1988, 7, 78.
11 N. Kuhn, P. Faupel and E. Zauder, J. Organomet. Chem., 1986, 302,
C4–C6.
12 W. Levason, M. Nirwan, R. Ratnani, G. Reid, N. Tsoureas and M.
Webster, Dalton Trans., 2007, 439.
13 G. M. Sheldrick, SHELXS-97, Program for crystal structure solution,
University of Go¨ttingen, Germany, 1997.
14 G. M. Sheldrick, SHELXL-97, Program for crystal structure refinement,
University of Go¨ttingen, Germany, 1997.
15 F. Cheng, A. L. Hector, W. Levason, G. Reid, M. Webster and W.
Zhang, Inorg. Chem., 2007, 46, 7215.
No adduct formation is seen for the heavier Tl(lII) chloride
with Me2E, instead the systems undergo redox chemistry giving
Me2ECl2 for E = Se or Te.
16 F. Cheng, A. L. Hector, W. Levason, G. Reid, M. Webster and W.
Zhang, Inorg. Chem., 2008, 47, 9691.
17 K. Nakamoto, IR Spectra of Inorganic and Coordination Compounds,
Wiley, New York, 2nd edn, 1970.
18 J. Mason, Multinuclear NMR, Plenum, New York, 1987.
19 A. J. Blake, G. Reid and M. Schro¨der, J. Chem. Soc. Dalton Trans.,
1989, 1675.
20 R. D. Shannon and R. D. Prewitt, Acta Crystallogr., Sect. B, 1970,
26, 1046; R. D. Shannon and R. D. Prewitt, Acta Crystallogr., Sect. B,
1969, 25, 925.
Acknowledgements
We thank the Commonwealth Commission UK for the award of
a scholarship to C. G. and EPSRC for support.
21 N. P. Luthra and J. D. Odon, in The Chemistry of Organic Selenium
and Tellurium Compounds, ed. S. Patai and Z. Rappoport, Wiley, NY,
1986, vol. 1, ch. 6; H. C. E. McFarlane and W. McFarlane, J. Chem.
Soc. Dalton Trans., 1973, 2416.
22 H. Duddeck, Progr. NMR Spectros., 1995, 27, 1.
23 J. R. Gauvreau, S. Poignant and G. J. Martin, Tetrahedron Lett., 1980,
21, 1319.
24 A. J. Blake, J. A. Greig and M. Schro¨der, J. Chem. Soc. Dalton Trans.,
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Schro¨der, J. Chem. Soc. Dalton Trans., 1998, 3961.
25 N. J. Hill, W. Levason, M. E. Light and G. Reid, Chem. Commun., 2003,
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