Synthesis and properties of ditelluroether complexes of osmium, trans-[OsCl2 (L-L)] and trans-[OsCl(PPh3) (L-L)2]PF6 (L-L = o-C6H4(TeMe)2, RTe(CH2)3TeR (R=P

Article abstract of DOI:10.1016/S0277-5387(99)00376-9

The complexes trans-[OsCl₂(L-L)₂] (L-L=o-C₆H₄(TeMe)₂, RTe(CH₂)₃TeR (R=Ph or Me)) have been prepared from trans-[OsCl₂(dmso)₄] and the ditelluroethers in eth

Full text of DOI:10.1016/S0277-5387(99)00376-9

www.elsevier.nl/locate/poly
Polyhedron 19 (2000) 235–240
Synthesis and properties of ditelluroether complexes of osmium, trans-
[OsCl2(L-L)2] and trans-[OsCl(PPh3)(L-L)2]PF6 (L-Lso-
C6H4(TeMe)2, RTe(CH2)3TeR (RsPh or Me))
*
Andrew J. Barton, William Levason , Gillian Reid, Vicki-Anne Tolhurst
Department of Chemistry, University of Southampton, Southampton SO17 1BJ, UK
Received 27 September 1999; accepted 17 November 1999
Abstract
The complexes trans-[OsCl2(L-L)2] (L-Lso-C6H4(TeMe)2, RTe(CH2)3TeR (RsPh or Me)) have been prepared from trans-
[OsCl2(dmso)4] and the ditelluroethers in ethanol. The reaction of [OsCl2(PPh3)3] with the ditelluroethers or MeSCH2CH2SMe or
MeSe(CH2)3SeMe in ethanol in the presence of NH4PF6 gave trans-[OsCl(PPh3)(L-L)2]PF6. The complexes have been characterised by
analysis, IR, UV–Vis and multinuclear NMR spectroscopy. The reaction of OsO4–HCl–EtOH with PhTe(CH2)3TePh results in chlorination
of the ligand to PhTeCl2(CH2)3TePhCl2, identified by single-crystal X-ray study. The X-ray structure for trans-[OsCl2{PhTe(CH2)3TePh}2]
is reported. The reaction of [OsCl2(dmso)4] with the distibine Ph2Sb(CH2)3SbPh2 affords trans-[OsCl2{Ph2Sb(CH2)3SbPh2}2] which has
also been characterised crystallographically.
q2000 Elsevier Science Ltd All rights reserved.
Keywords: Osmium; Ditelluroether; X-ray structures
1. Introduction
2. Results and discussion
The reaction of OsO4–conc. HCl–EtOH with the three
ditelluroether ligands (L-Lso-C6H4(TeMe)2, or RTe-
(CH2)3TeR (RsMe or Ph)) at 08C gave brownish-purple
solids leaving a dark red solution. These solids lacked the
very strong n(OsO2) IR vibration at ca. 850 cmy1 typical of
trans-[OsO2Cl2(L9-L9)] (L9-L9sdithioether or diseleno-
ether) [4,5], ruling out the formation of osmyl species. A
similar result was reported with Me2Te [4,5]. Since tellu-
roethers are both stronger reducing agents and less able to
stabilise high oxidation states than their lighteranalogues[6–
8], their failure to stabilise Os(VI) is not unexpected, but it
was hoped that reduction would lead to Os(III) or Os(IV)
complexes. The brownish-purple solids have UV–Visspectra
typical of Os(IV), in fact the major features are very similar
to those of [OsCl6]2y [9] and were weakly paramagnetic,
which would suggest either Os(IV) and/or Os(III) com-
pounds were present. However, after long accumulations
each sample gave a single sharp 125Te NMR resonance at
very high frequencies (d (125Te) ca. 800–900) which would
seem to indicate that at least some of the telluriumwaspresent
in a diamagnetic material, the shifts being in the range [10]
typical of R2TeCl2 species. A pale brown crystal was grown
(from MeCN) from the PhTe(CH2)3TePh reaction and the
Osmium forms compounds in formal oxidationstatesrang-
ing from 8 to y2 and as a consequence has an extremely rich
coordination chemistry [1]. However, the absence of labile
osmium precursors in the medium oxidation states can make
some types of complex difficult to prepare. For example,
whilst a wide range of bidentate and polydentate phosphine
and arsine complexes of Os(II), Os(III) and Os(IV) are
readily made starting from OsO4–HX–ROH (XsCl, Br or
I) or [OsX6]2y [1], obtaining complexes with Group 16
donors has proved considerably more difficult. Direct reac-
tion of [OsX6]2y with dithioethers [2] or diselenoethers[3]
generates [OsX4(L-L)] type complexes in poor yield, whilst
from OsO4–HX–EtOH and the ligands at low temperatures
unstable osmyl complexes [OsO2X2(L-L)] form [4,5]. Fur-
ther reduction to, for example, [OsX2(L-L)2] does not
appear possible by this route. We were interestedinextending
our previous studies of ditelluroether complexes with plati-
num group metals, Pt or Pd [6–8], Ir [6,7], Ru or Rh [8],
to osmium and report our investigations below.
* Corresponding author. Tel.: q44-1703-543792; fax: q44-1703-
593781; e-mail: wxl@soton.ac.uk
0277-5387/00/$ - see front matter q2000 Elsevier Science Ltd All rights reserved.
PII S0277-5387(99)00376-9
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236
A.J. Barton et al. / Polyhedron 19 (2000) 235–240
Table 1
structure solution revealed the diamagnetic tellurium com-
pound to be PhCl2Te(CH2)3TePhCl2.MeCN 1. The structure
is shown in Fig. 1 and selected bond length and angle data
are in Table 1. The structure is typical of R2TeCl2 type com-
pounds, with PhCl2TeCH2TePhCl2 the closest structurally
characterised example [11]. The environment about each Te
is based upon a distorted trigonal bipyramid with axial TeCl2
groups and with one equatorial position vacant, presumably
occupied by the lone pair. The Te–Cl bonds 2.504(2)–
˚
Selected bond lengths (A) and angles (8) for PhCl2Te(CH2)3-
TePhCl2PMeCN
Te(1)–Cl(1)
Te(1)–Cl(1)
Te(2)–Cl(3)
Te(2)–C(3)
2.507(1)
2.169(5)
2.520(2)
2.169(6)
Te(1)–Cl(2)
Te(1)–C(4)
Te(2)–Cl(4)
Te(2)–C(10)
2.524(1)
2.131(6)
2.504(2)
2.150(6)
Cl(1)–Te(1)–Cl(2)
Cl(1)–Te(1)–C(4)
Cl(2)–Te(1)–C(4)
Cl(3)–Te(2)–Cl(4)
Cl(3)–Te(2)–C(10)
Cl(4)–Te(2)–C(10)
Te(1)–C(1)–C(2)
Te(2)–C(3)–C(2)
175.01(5) Cl(1)–Te(1)–C(1)
89.3(2)
86.2(2)
176.54(5) Cl(3)–Te(2)–C(3)
91.3(2)
91.5(2)
85.3(2)
93.1(2)
99.1(2)
88.1(2)
89.7(2)
94.6(2)
110.8(5)
Cl(2)–Te(1)–C(1)
C(1)–Te(1)–C(4)
˚
2.524(1) A lie within the usual range [11], and the structure
is unexceptional, but serves to identify unequivocally a sig-
nificant product of the reactions described above.
Cl(4)–Te(2)–C(3)
C(3)–Te(2)–C(10)
C(1)–C(2)–C(3)
114.7(4)
112.3(4)
Similar brownish-purple materials are formed on refluxing
[NH4]2[OsCl6] with the ditelluroethers in alcohols. Notably
none of the crude materials gave 125Te NMR resonances in
the ranges we subsequently observed for the [OsCl2(L-L)2]
complexes (below). Although we have been unable to sep-
arate any pure osmium species from these reactions, it isclear
that the target [OsCl2(L-L)2] are not present in significant
amounts.
An alternative route to trans-[OsCl2(L-L)2] from Os(II)
starting materialswassought, althoughasindicatedinSection
1, most Os(II) materials are kinetically very inert and intro-
ducing moderate donor ligands like telluroethers is not easy.
We found that the recently characterised [12] trans-
[OsCl2(dmso)4] (dmsosdimethylsulfoxide) reacted with
the ditelluroethers under reflux in ethanol to produce poor to
moderate yields of trans-[OsCl2(L-L)2] as orange or red
solids. The isolated complexes are air stable and generally
poorly soluble in chlorocarbons or MeCN, which to some
extent limited solution spectroscopic studies. Red crystals of
[OsCl2{PhTe(CH2)3TePh}2] were obtained by evaporation
of a CHCl3 solution of the complex, and the structuresolution
(Table 2, Fig. 2) revealed a trans pseudo-octahedral mole-
cule with the osmium on the inversion centre and with both
ditelluroethers in meso form. Although the crystals are not
isomorphous, the structure is very similar to that previously
found in trans-[RuCl2{PhTe(CH2)3TePh}2] [8]. The Os–
Table 2
˚
Selected bond lengths (A) and angles (8) for [OsCl2{PhTe(CH2)3TePh}2]
Os(1)–Te(1)
Os(1)–Te(2)
Os(1)–Cl(1)
Te(1)–C(1)
Te(1)–C(11)
Te(2)–C(3)
Te(2)–C(21)
2.6135(9)
2.616(1)
2.450(4)
2.18(1)
2.13(1)
2.18(1)
2.14(1)
Te(1)–Os(1)–Te(2)
Te(1)–Os(1)–Cl(1)
Te(2)–Os(1)–Cl(1)
86.65(3)
93.15(8)
93.12(9)
1 Although RCl2Te(CH2)nTeRCl2 prepared from RTe(CH2)nTeR and Cl2
are white or cream, our crystals were brown, presumably owing to traces of
an osmium species.
Fig. 2. View of the structure of [OsCl2{PhTe(CH2)3TePh2]withnumbering
scheme adopted. Ellipsoids are drawn at 40% probability. Atoms marked *
are related by a crystallographic inversion centre. H-atoms are omitted for
clarity.
˚
Cl bond length, 2.450(4) A, is comparable with those found
˚
in [OsCl2{Ph2PCH2CH2PPh2)2] (2.434(1) A) [13] and
˚
[OsCl2{H2C_C(PPh2)2}2] (2.431(1) A) [14]. There are
no literature data on OsII–TeR2 bonds, but those in the present
˚
complex (2.616(1), 2.6135(9) A) are, asmightbeexpected,
similar to the Ru–Te bonds in the RuII analogue (2.6247(3),
˚
2.6194(3) A) [8].
Fig. 1. View of the structure of PhTeCl2(CH2)3TePhCl2 with numbering
scheme adopted. Ellipsoids are drawn at 40% probability.
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237
The three [OsCl2(L-L)2] complexes have very similar
spectroscopic properties (Section 3) including two d–d
bands in the range 21000–26000 cmy1 as expected for a low
spin d6 complex with local D4h symmetry [9]. The poor
solubility made it very difficult to obtain 125Te NMR spectra,
but after very long accumulations several resonances were
present in each complex, consistent with a mixture of inver-
tomers, showing that pyramidalinversionisslowontheNMR
time scale in these systems. As we have discussed elsewhere
[8], it is not possible to assign resonances to individual iso-
mers. Notably, for comparable complexes, the d(125Te) are
found at considerablyhigherfrequencyintherutheniumcom-
plexes [8] compared with the present osmium examples, an
effect also found for corresponding ruthenium and osmium
phosphines [15]. Cyclic voltammetry of the complexes in
CH2Cl2 revealed a single reversible oxidation for each
([OsCl2{MeTe(CH2)3TeMe}2] q0.35 V versus SCE;
[OsCl2{PhTe(CH2)3TePh}2] q0.18 V; [OsCl2{o-C6H4-
(TeMe)2}2] q0.43 V), which contrasts with the quasi-
reversible or irreversible oxidations observed in the
ruthenium analogues [8], reflecting the expected greater sta-
bility of the M(III) state for osmium.
with one meso and one DL ditelluroether. The pattern of
invertomers in these two cases is very similar to that observed
in the ruthenium analogues [8]. For the [OsCl(PPh3)-
{MeSe(CH2)3SeMe}2]PF6 the 31P{1H} NMR spectrum
shows a singlet at y14.0 and the septet at y145. There are
singlets for the Me and CH2 groups of the diselenoether in
1
the H NMR spectrum. Whilst at first sight this might be
taken to indicate one isomer with high symmetry, we were
unable to observe a 77Se NMR spectrum from this complex,
which suggests that pyramidal inversionisoccurring.Finally,
for [OsCl(PPh3){MeS(CH2)2SMe}2]PF6 there is a singlet
in the 31P{1H} NMR spectrum at d y15.1, and broad singlets
at d 2.44 and 2.7 (in addition to the Ph multiplet) in the 1H
NMR spectrum, consistent with fast inversion in the
dithioether complex. The poor solubility and the number of
possible invertomers make these systems poorly suited to VT
NMR studies, but comparison of the room temperature spec-
tra shows the usual trends [16,17] in pyramidal inversion
barriers Te)Se)S are present.
The reaction of [OsCl6]2y with Ph3Sb in alcohols readily
yieldsmer-[OsCl3(Ph3Sb)3]whichcanbereducedbyexcess
ligand and NaBH4 to trans-[OsCl2(Ph3Sb)4] [18,19], but
attempts to carry out corresponding reactions with ditertiary
stibines failed. As a further test of the usefulness of
[OsCl2(dmso)4] we reacted this with Ph2Sb(CH2)3SbPh2
in ethanol, and readily obtained good yields of yellow trans-
[OsCl2{Ph2Sb(CH2)3SbPh2}2]. The spectroscopic data
(Section 3) are unexceptional and compare well with the
corresponding data on trans-[OsCl2(Ph3Sb)4] [18,19] and
trans-[OsCl2(diphosphine)2] [20]. Yellow crystals of
trans-[OsCl2(Ph2Sb(CH2)3SbPh2)2] were obtained from
CH2Cl2, and the structure determined. The molecule isshown
in Fig. 3 and significant bond lengths and angles are in Table
3. The structure reveals a centrosymmetric molecule, with
Although [OsCl2(dmso)4]providedasatisfactorystarting
material for the synthesis of the ditelluroether complexes it
is still not ideal, and attempts to prepare [OsCl2(L9-L9)2]
(L9-L9 dithioether or diselenoether) similarly usually result
in mixtures containing [OsCl(dmso)(L9-L9)2]q, [OsCl2-
(dmso)2(L9-L9)] and [OsCl2(L9-L9)2], which are not read-
ily separated, and we have not obtained useful amounts of
the last complexes.
The reactions of [OsCl2(PPh3)3] with 2 equiv. of the
Group 16 ligands in EtOH in the presence of [PF6]y gave
moderate yields of [OsCl(PPh3)(L-L)2]PF6 (L-Ls
RTe(CH2)3TeR, RsMe or Ph), [OsCl(PPh3)(MeSCH2-
CH2SMe)2]PF6 and [OsCl(PPh3){MeSe(CH2)3SeMe}2]-
PF6 as yellow or brown solids. The complexes are air stable
solids which show [OsCl(PPh3)(L-L)2]q as the highest
mass ions in their ESq mass spectra. The UV–Vis spectra are
uninformative, showing only the p™p* transitions of the
Ph-groups and charge transfer transitions in the near-UV
which tail into the visible obscuring the d–d bands, although
the absence of significant features below 20000 cmy1 con-
firms the oxidation state as Os(II). The 1H NMR spectra of
the ditelluroether compounds are complex and not very help-
ful, but the 31P{1H} NMR spectra are more useful. For
[OsCl(PPh3){PhTe(CH2)3TePh}2]PF6, in addition to the
septet at d y145 due to [PF6]y there are two singlets at
y10.5 and y11.8 with approximate intensities 2:1 showing
the presence of two major invertomers. The corresponding
125Te{1H} NMR spectrum showed five doublets in the range
d 450–565 with 2J(125Te–31P) of ca. 60–90 Hz. In the case
of [OsCl(PPh3){MeTe(CH2)3TeMe}2]PF6 the 31P{1H}
NMR spectrum reveals one major invertomer d y14.5 and
there are four doublets in the 125Te{1H} NMR spectrum and
˚
the d(Os–Cl) 2.477(2) A typical of an Os(II) centre
˚
[13,14]. The d(Os–Sb) 2.5933(8), 2.6030(4) A are very
similar to those in trans-[OsCl2(Ph3Sb)4] (2.611(2)–
˚
2.630(2) A) [21].
3. Experimental
Physical measurements were made asdescribedpreviously
[8].
3.1. [Os{MeTe(CH2)3TeMe}2Cl2]
[Os(dmso)4Cl2] (151 mg, 0.155 mmol), MeTe-
(CH2)3TeMe (100 mg, 0.307 mmol) in MeOH (70 cm3)
were refluxed for 16 h. The solvent was removed in vacuo
and CH2Cl2 added (2 cm3). The orange solution was filtered
and Et2O added to precipitate an orange solid. Yield: 0.05 g,
36%. Anal. Found: C, 12.9; H, 2.6. Calc. forC10H24Cl2OsTe4:
C, 13.1; H, 2.6%. 1H NMR (CDCl3, 300 MHz): d 1.94–3.15
(m, CH2qCH3). 125Te{1H} NMR (CDCl3/CH2Cl2, 113
MHz): d 236, 267, 274, 286, 293, 329, 339. IR spectrum
1
four d(Me) resonances in the H NMR spectrum. This is
consistent with one invertomer as the major solution form
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Fig. 3. View of the structure of [OsCl2{Ph2Sb(CH2)3SbPh2}2] with number scheme adopted. Ellipsoids are drawn at 40% probability. Atoms marked * are
related by a crystallographic inversion centre. H-atoms are omitted for clarity.
nmaxs22125 (´mols330), 20580 (sh) cmy1 (250 dm3
Table 3
˚
Selected bond lengths (A) and angles (8) for [OsCl2{Ph2Sb-
(CH2)3SbPh2}2]P2CH2Cl2
moly1 cmy1).
3.2. [Os{PhTe(CH2)3TePh}2Cl2]
Os(1)–Sb(1)
Os(1)–Sb(2)
Os(1)–Cl(1)
Sb(1)–C(3)
Sb(1)–C(6)
Sb(1)–C(7)
Sb(2)–C(1)
Sb(2)–C(4)
Sb(2)–C(5)
2.5933(8)
2.6030(4)
2.477(2)
2.154(7)
2.137(7)
2.149(7)
2.143(7)
2.137(7)
2.144(7)
The method usedwasthesameasforthepreviouscomplex,
giving a red powder. Yield: 40 mg, 32%. Anal. Calc. for
C30H32Cl2OsTe4: C, 31.0; H, 2.8. Found: C, 30.8; H, 2.9%.
1H NMR (CDCl3, 300 MHz): d 3.0–3.5 (6H, CH2), 7.4–7.9
(10H, Ph). 125Te{1H} NMR (CDCl3/CH2Cl2 113 MHz): d
478, 489, 513, 523, 548. IR spectrum (CsI disc): 3042 (m),
2921 (w), 1571 (m), 1474 (s), 1433 (s), 1415 (m), 1396
(m), 1359 (s), 1200 (m), 1061 (m), 1018 (m), 996 (m),
754 (w), 730 (s), 691 (s), 614 (w), 490 (w), 453 (w),
259 (w), 227 (w). UV–Vis spectrum (MeCN):
nmaxs21000 (´mols180), 24600 (540), 38300 cmy1
(18235 dm3 moly1 cmy1).
Sb(1)–Os(1)–Sb(2)
Sb(1)–Os(1)–Cl(1)
Sb(2)–Os(1)–Cl(1)
Os(1)–Sb(1)–C(3)
Os(1)–Sb(1)–C(6)
Os(1)–Sb(1)–C(7)
C(3)–Sb(1)–C(6)
C(3)–Sb(1)–C(7)
C(6)–Sb(1)–C(7)
Os(1)–Sb(2)–C(1)
Os(1)–Sb(2)–C(4)
Os(1)–Sb(2)–C(5)
C(1)–Sb(2)–C(4)
C(1)–Sb(2)–C(5)
C(4)–Sb(2)–C(5)
85.73(1)
95.53(4)
96.76(4)
114.2(2)
124.2(2)
117.1(2)
100.1(3)
96.9(3)
99.7(3)
3.3. [Os{o-C6H4(TeMe)2}2Cl2]
114.3(2)
118.9(2)
123.6(2)
95.7(3)
98.5(3)
100.8(3)
The method usedwasthesameasforthepreviouscomplex,
giving an orange powder. Yield: 29%. Anal. Calc. for
C16H20Cl2OsTe4: C, 19.5; H, 2.1. Found: C, 19.4; H, 1.9%.
1H NMR (CDCl3, 300 MHz): d 2.05–2.3 (6H, CH3), 7.2–
7.8 (4H, C6H4). 125Te{1H} NMR (CDCl3/CH2Cl2 113
MHz): d 656, 663, 671, 672, 673. Electrospray mass spec-
trum (MeCN) m/z: found Mq 992, 948; calc. for
(CsI disc): 2922 (m), 2855 (w), 1358 (s), 1262 (w), 1091
(s), 1068, 920 (w), 835 (m), 615 (w), 598 (w), 430 (w),
297 (m), 224 (w). UV–Vis spectrum (CH2Cl2):
[
192Os{C6H4(130TeMe)}235ClqMeCN]q 1000, [192Os-
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239
{C6H4(130TeMe)}235Cl]q 959. IR spectrum (CsI disc):
2923 (w), 2851 (w), 1358 (s) 1260 (w), 1080 (s), 1019
(m), 835 (m), 753 (m), 685 (w), 614 (w), 548 (w), 427
(w), 326 (w), 302 (w). UV–Vis spectrum (MeCN):
nmaxs22600 cmy1 (´mols590), 33200 (sh) cmy1 (6300
dm3moly1cmy1).
C48H47ClF6OsP2Te4: C, 37.5; H, 3.0. Found: C, 37.9; H,
2.4%. Electrospray mass spectrum (MeCN) m/z: found Mq
1391; calc. for [192Os35Cl(PPh3)(PhTe(CH2)3TePh)2]q
1401. IR (CsI disc): 3050 (w), 2932 (w), 1477 (w), 1435
(m), 1362 (m), 1088 (m), 1017 (w), 938 (s), 735 (s), 688
(s), 558 (m), 536 (m), 454 (w), 250 (m). 1H NMR (300
MHz CDCl3): d 2.2 (m), 2.9–3.3 (m), 7.0–7.8(m). 31P{1H}
(145 MHz, CH2Cl2/CDCl3): d y10.5(s), y11.8(s), y145
(septet). 125Te{1H} NMR (114 MHz, CH2Cl2/CDCl3): d
454, 463, 499, 540, 565.
3.4. [OsCl(PPh3)(MeSCH2CH2SMe)2]PF6
[OsCl2(PPh3)3] (0.1 g, 0.095 mmol) and
MeSCH2CH2SMe (0.06 g, 0.29 mmol) were refluxed
together in ethanol (10 cm3) for 2 h, during which time the
colour changed from green to orange. After cooling to room
temperature, NH4PF6 (0.06 g, 0.32 mol) was added and the
solution concentrated to 3 cm3 to give an orange solid, which
was filtered off and recrystallised from CH2Cl2–Et2O. Yield:
0.069 g, 70%. Anal. Calc. for C26H35ClF6OsP2S4: C, 35.5; H,
4.0. Found: C, 35.0; H, 3.3%. Electrospray mass spectrum
(MeCN) m/z: found Mq 734; calc. for [192Os35Cl(PPh3)-
(MeSCH2CH2SMe)2]q 733. IR (CsI disc): 2930 (w), 1435
(m), 1357 (m), 1091 (m), 839 (s), 750 (m), 699 (s), 516
(m), 504 (m). 1H NMR (300 MHz CDCl3): d 2.6 (s), 2.74
(s). 31P{1H} (145 MHz, CH2Cl2/CDCl3): d y15.1 (s),
y147 (septet).
3.8. [OsCl2(Ph2Sb(CH2)3SbPh2)2]
[OsCl2(dmso)4] (0.05 g, 0.09 mmol) and
Ph2Sb(CH2)3SbPh2 (0.16 g, 0.27 mmol) were refluxed
together in ethanol (10 cm3) for 3 h. The solvent was
removed in vacuo, CH2Cl2 added to the residue, the solution
filtered and the orange product precipitated with Et2O. Yield:
0.045 g, 35%. Anal. Calc. for C54H52Cl2OsSb4PCH2Cl2: C,
43.1; H, 3.4. Found: C, 43.1; H, 2.8%. Electrospray mass
spectrum (MeCN) m/z: found Mq 1450. calc. for
[
192Os35Cl2(Ph2121Sb(CH2)3121SbPh2)2]q 1446. IR (CsI
disc): 3066 (m), 3049 (m), 1480 (w), 1432 (s), 1360 (m),
1102 (m), 1069 (s), 998 (m), 727 (s), 695 (s), 451 (s),
267 (m). UV–Vis spectrum (CH2Cl2): nmaxs30860 (sh),
(´mols2200), 22230 (sh) cmy1 (250 dm3 moly1 cmy1).
13C{1H} NMR (CH2Cl2/CDCl3): d 15.8, 24.3, 128–137. CV
CH2Cl2: reversible q0.3 V versus SCE.
3.5. [OsCl(PPh3)(MeSeCH2CH2CH2SeMe)2]PF6
The method used was similar to that described in Section
3.4, giving a brown solid. Yield: 70%. Anal. Calc. for
C28H39ClF6OsP2Se4: C, 30.9; H, 3.2. Found: C, 30.2; H,
3.0%. Electrospray mass spectrum (MeCN) m/z: found
Mq 949; calc. for [192Os35Cl(PPh3)(Me80SeCH2CH2-
80SeMe)2]q 753. IR (CsI disc): 2927 (w), 2850 (w), 1434
(w), 1413 (w), 1089 (m), 999 (w), 840 (s), 751 (m), 699
3.9. X-ray structure determination of PhTeCl2(CH2)3-
TeCl2PhPMeCN, [OsCl2{PhTe(CH2)3TePh}2]
and [OsCl2{Ph2Sb(CH2)3SbPh2}2]P2CH2Cl2
1
(s), 558 (s), 537 (m), 499 (w), 440 (w). H NMR (300
Details of the crystallographic data collection and refine-
ment parameters are given in Table 4. Data collection used a
Rigaku AFC7S four-circle diffractometer operating at
150 K (except for PhCl2Te(CH2)3TePhCl2PMeCN, 295 K),
using graphite-monochromated Mo Ka X-ray radiation
MHz CDCl3): d 1.72 (q), 2.25 (s), 2.85 (t), 7.4–7.7 (m).
31P{1H} (145 MHz, CH2Cl2/CDCl3): d y14.0(s), y147
(septet).
3.6. [OsCl(PPh3){MeTe(CH2)3TeMe}2]PF6
˚
(ls0.71073 A). For PhCl2Te(CH2)3TePhCl2PMeCN(295
K) preliminary psi-scans showed no significant absorption.
The structure was solved by direct methods [22] and refined
by iterative cycles of least-squares refinement [23]. All non-
H atoms were refined anisotropically and H atoms were
placed in fixed, calculated positions. Selected bond lengths
and angles are given in Table 1. For [OsCl2{PhTe-
(CH2)3TePh}2] preliminary psi scans did not provide a sat-
isfactory absorption correction, hence, with the model at
isotropic convergence, the data were corrected for absorption
using DIFABS [24]. and for [OsCl2{Ph2Sb(CH2)3-
SbPh2}2]P2CH2Cl2 the data were corrected for absorption
using psi-scans. Both Os structures were solved by heavy
atom methods [25] and developed by iterative cycles of full-
matrix least-squares refinement [23] and difference Fourier
syntheses. All fully occupied non-H atoms were refined ani-
sotropically and H-atoms were placed in fixed, calculated
positions (the H atoms associatedwiththedisorderedCH2Cl2
The method used was the same as described in Section 3.4,
giving a yellow solid. Yield: 75%. Anal. Calc. for
C28H39ClF6OsP2Te4: C, 26.1; H, 3.0. Found: C, 26.5; H,
2.1%. Electrospray mass spectrum (MeCN) m/z: found Mq
1143; calc. for [192Os35Cl(PPh3)(Me130Te(CH2)3Me)2]q
1153. IR (CsI disc): 2921 (w), 1634 (w), 1417 (w), 1201
(w), 1088 (m), 841 (s), 753 (w), 688 (m), 556 (m), 539
1
(m), 517 (w), 278 (w). H NMR (300 MHz CDCl3): d
1.57 (m), 1.78 (s), 1.96 (s), 2.02 (s), 2.25 (s), 3.2–3.4
(m), 7.4–7.6 (m). 31P{1H} (145 MHz, CH2Cl2/CDCl3): d
y13.0 (s), y147 (septet). 125Te{1H} NMR (114 MHz,
CH2Cl2/CDCl3): d 361, 411, 422, 430.
3.7. [OsCl(PPh3){PhTe(CH2)3TePh}2]PF6
The method used was the same as described in Section 3.4,
giving a yellow solid. Yield: 87%. Anal. Calc. for
Monday Feb 21 09:44 AM
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240
A.J. Barton et al. / Polyhedron 19 (2000) 235–240
Table 4
Crystallographic data
PhTeCl2(CH2)3TePhCl2PMeCN [OsCl2{PhTe(CH2)3TePh}2] [OsCl2{Ph2Sb(CH2)3SbPh2}2]P2CH2Cl2
Formula
FW
C17H19Cl4NTe2
639.37
Monoclinic
P21/n
7.931(3)
26.889(4)
10.695(3)
90
110.20(2)
90
C30H32Cl2OsTe4
1164.09
monoclinic
P21/n
8.684(5)
7.225(6)
25.205(2)
90
94.00(2)
90
1577(1)
2
C56H56Cl6OsSb4
1618.98
triclinic
Crystal system
Space group
P-1
˚
a (A)
12.096(3)
12.226(3)
11.510(4)
107.43(2)
114.96(3)
96.17(2)
1417.4(9)
1
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
3
˚
U (A )
2140(1)
4
1.968
Z
Dcalc (g cmy3
)
2.451
78.54
1.897
44.28
m(Mo Ka) (cmy1
)
32.25
Absolute correction (max., min. transmission
1.000, 0.559
1.000, 0.479
factors)
Unique observed reflections
Observed reflections with I0)2s(I0)
No. of parameters
3872
2785
217
0.027
0.032
3040
2254
169
0.052
0.058
4983
4308
297
0.036
0.052
R a
b
Rw
a Rs8(NFobsNiyNFcalcNi)/8NFobsNi.
b Rws6[8wi(NFobsNiyNFcalcNi)2/8wiNFobsNi ].
2
[7] T. Kemmitt, W. Levason, Inorg. Chem. 29 (1990) 731.
[8] W. Levason, S.D. Orchard, G. Reid, V.-A. Tolhurst. J. Chem. Soc.,
Dalton Trans. (1999) 2071.
[9] A.B.P. Lever, Inorganic Electronic Spectroscopy, Elsevier, New
York, 2nd edn., 1984.
[10] N.P. Luthra, J.D. Odom, in: S. Patai, Z. Rappoport (Eds.), The Chem-
istry of Organic Selenium and Tellurium Compounds, vol. 1, Wiley,
New York, 1986, p. 189.
[11] R.J. Batchelor, F.W.B. Einstein, C.H.W. Jones, R.D. Sharma,
Organometallics 6 (1987) 2164.
solvent molecules were omitted from the final structurefactor
calculation). In both cases the Os(II) species was found to
have crystallographic inversion symmetry, with the Os atom
occupying an inversion centre. Two half CH2Cl2 solventmol-
ecules, disordered across crystallographic inversion centres,
were also identified in the asymmetric unit in the structure of
[OsCl2{Ph2Sb(CH2)3SbPh2}2]. Selected bond lengths and
angles are given in Tables 2 and 3.
[12] A.M. McDonagh, M.G. Humphrey, D.C.R. Hockless, Aust. J. Chem.
51 (1998) 807.
[13] W. Levason, N.R. Champness, M. Webster, Acta Crystallogr., Sect.
C 49 (1993) 1884.
[14] F.A. Cotton, M.P. Diebold, M. Matusz, Polyhedron 6 (1987) 1131.
[15] N.J. Holmes, W. Levason, M. Webster, J. Chem. Soc., Dalton Trans.
(1997) 4223.
Supplementary data
Supplementary datahavedepositedattheCambridgeCrys-
tallographic Data Centre, CCDC reference numbers135001–
135003.
[16] E.W. Abel, S.K. Bhargava, K.G. Orrell, Prog. Inorg. Chem. 32(1984)
1.
[17] E.W. Abel, K.G. Orrell, S.P. Scanlan, D. Stephenson, T. Kemmitt, W.
Levason. J. Chem. Soc., Dalton Trans. (1991) 591.
[18] N.R. Champness, W. Levason, R.A.S. Mould, D. Pletcher, M. Web-
ster, J. Chem. Soc., Dalton Trans. (1991) 2777.
[19] R.A.S. Mould, Ph.D. Thesis, University of Southampton, 1991.
[20] N.R. Champness, W. Levason, D. Pletcher, M.D. Spicer, M. Webster,
J.Chem. Soc., Dalton Trans. (1992) 2201.
[21] N.R. Champness, W. Levason, M. Webster, Inorg. Chim. Acta 208
(1993) 189.
[22] G.M. Sheldrick, SHELXS-86, Acta Crystallogr., Sect. A 46 (1990)
467.
Acknowledgements
We thank the EPSRC for support and Johnson Matthey plc
for generous loans of osmium.
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