Osmadisiloxane and osmastannasiloxane complexes derived from silanolate complexes of osmium(II)

Article abstract of DOI:10.1016/j.ica.2004.07.058

Treatment of the five-coordinate chlorodimethylsilyl complex, Os(SiMe ₂Cl)Cl(CO)(PPh₃)₂ with hydroxide readily produces Os(SiMe₂OH)Cl(CO)(PPh₃)₂ (1). Complex 1 is deprotonated by ^t

Full text of DOI:10.1016/j.ica.2004.07.058

Inorganica Chimica Acta 358 (2005) 1407–1419
www.elsevier.com/locate/ica
Osmadisiloxane and osmastannasiloxane complexes derived from
silanolate complexes of osmium(II)
Markus Albrecht, Wai-Him Kwok, Guo-Liang Lu, Clifton E.F. Rickard,
*
Warren R. Roper , David M. Salter, L. James Wright
Department of Chemistry, The University of Auckland, Private Bag 92019, Auckland, New Zealand
Received 13 June 2004; accepted 17 July 2004
Dedicated to Professor F.G.A. Stone, CBE, FRS, in celebration of his remarkable career and his continuing
contributions to inorganic and organometallic chemistry
Abstract
Treatment of the five-coordinate chlorodimethylsilyl complex, Os(SiMe2Cl)Cl(CO)(PPh3)2 with hydroxide readily produces
t
Os(SiMe2OH)Cl(CO)(PPh3)2 (1). Complex 1 is deprotonated by BuLi giving the silanolate complex, Os(SiMe2OLi)Cl(CO)(PPh3)2
(2), which reacts further with Me3SiCl or Me3SnCl to give Os(SiMe2OSiMe3)Cl(CO)(PPh3)2 (3) or Os(SiMe2OSnMe3)Cl-
(CO)(PPh3)2 (4), respectively. The structures of 3 and 4 have been determined by X-ray crystallography. Reaction between
OsH(j2-S2CNMe2)(CO)(PPh3)2 and HSiMe2Cl gives Os(SiMe2Cl)(j2-S2CNMe2)(CO)(PPh3)2 (5). This six-coordinate chlorodimeth-
ylsilyl complex, is unreactive towards hydroxide at room temperature and at 60 ꢀC forms Os[Si(OH)3](j2-S2CNMe2)(CO)(PPh3)2
(7). Complex 5 is, however, smoothly converted to the hydroxy derivative, Os(SiMe2OH)(j2-S2CNMe2)(CO)(PPh3)2 (6) upon chro-
t
matography on silica gel. Complex 6 is deprotonated by BuLi giving the intermediate silanolate complex, Os(SiMe2OLi)(j2-
S2CNMe2)(CO)(PPh3)2, which reacts further with Me3SiCl to give Os(SiMe2OSiMe3)(j2-S2CNMe2) (CO)(PPh3)2 (8). Crystal
structure determinations for 5, 6, 7, and 8 have been obtained and structural comparisons of these related compounds are made.
ꢁ 2004 Elsevier B.V. All rights reserved.
Keywords: Osmadisiloxane complex; Silyl complex; Silanolate complex; Osmium; X-ray crystal structure
1. Introduction
tant results include the conversion of metallasilanols to
both dimetalladisiloxanes (through condensation) [3]
and to metalladisiloxanes [1b]. In one instance, the con-
version of a metallasilanol to an isolated lithium metal-
lasilanolate (LnM–SiR2OLi) has been reported and this
was shown to be a dimer in the solid state [4].
The readily available five- and six-coordinate dimeth-
ylchlorosilyl–osmium(II) complexes, Os(SiMe2Cl)Cl(CO)-
(PPh3)2 and Os(SiMe2Cl)(j2-S2CNMe2)(CO)(PPh3)2,
provided the opportunity to access through hydrolysis,
the corresponding silanol complexes. We expected the
accompanying set of ligands in these compound to con-
stitute rather inert groupings and that, in effect, the
‘‘OsCl(CO)(PPh3)2’’ and ‘‘Os(j2-S2CNMe2)(CO)(PPh3)2’’
Metallasilanols (LnM–SiR2OH) [1], like the non-met-
allated analogues, are likely to be valuable synthetic
intermediates. Although these compounds are now
well-characterised and available through two principal
synthetic approaches (hydrolysis of halosilyl-ligands [1]
or reaction between dimethyldioxirane and a ligated
Si–H function [2]), the chemical reactivity associated
with M–Si–OH linkages is mostly unexplored. Impor-
*
Corresponding author. Tel.: +64 9 373 7999x8320; fax: +64 9 373
7422.
E-mail address: w.roper@auckland.ac.nz (W.R. Roper).
0020-1693/$ - see front matter ꢁ 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2004.07.058

1408
M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
fragments would provide unreactive and bulky substitu-
ents (‘‘handles’’), thus allowing focus on reactions at the
Si centres. We describe herein: (i) the simple hydrolysis
of Os(SiMe2Cl)Cl(CO)(PPh3)2 to Os(SiMe2OH)Cl(CO)-
(PPh3)2 (1); (ii) the deprotonation of 1 to a solid lithium
silanolate complex, Os(SiMe2OLi)Cl(CO)(PPh3)2 (2);
(iii) the reactions of 2 with Me3SiCl or Me3SnCl to give
the corresponding osmadisiloxane, Os(SiMe2OSiMe3)-
Cl(CO)(PPh3)2 (3), or osmastannasiloxane, Os(SiMe2-
OSnMe3)Cl(CO)(PPh3)2 (4), respectively; (iv) synthesis
of Os(SiMe2Cl)(j2-S2CNMe2)(CO)(PPh3)2 (5) and sub-
sequent hydrolysis on silica gel to Os(SiMe2OH)(j2-
S2CNMe2)(CO)(PPh3)2 (6); (v) the unusual reaction of
5 or 6 with KOH to give the trihydroxysilyl complex,
Os[Si(OH)3](j2-S2CNMe2)(CO)(PPh3)2 (7); (vi) the
transformation of Os(SiMe2OH)(j2-S2CNMe2)(CO)-
The IR spectrum of 1 shows a m(CO) band at 1910 cmꢀ1
.
As expected, this is lower than the corresponding band
for Os(SiMe2Cl)Cl(CO)(PPh3)2 which is found at 1917
cmꢀ1 in CH2Cl2 solution (the solid state spectrum, with
bands at 1932, 1918, 1905 cmꢀ1, is complicated by solid-
state splitting) [5]. In addition, the IR spectrum shows
an absorption at 3626 cmꢀ1 which is assigned to
1
m(OH). The H NMR also reveals the presence of the
Si–OH function with a resonance at 2.08 ppm which dis-
appears on addition of D2O. Other spectroscopic data
for 1 and all other new compounds described herein
are collected in Section 4.
The hydroxy function in 1 can be deprotonated with
tBuLi (see Scheme 1) and an orange solid, formulated
as Os(SiMe2OLi)Cl(CO)(PPh3)2 (2), can be isolated.
The IR spectrum of this orange solid shows a strong
m(CO) band at 1876 cmꢀ1. This band position is strik-
ingly lower than the m(CO) for 1 at 1910 cmꢀ1 but is
appropriate for a lithium silanolate salt. This formula-
tion is further supported by the reactions of 2 which
are described in the following section. The only other
compound of this type of which we are aware, is [Ir-
(SiiPr2OLi)HCl(PEt3)2]2 [4], where X-ray crystallogra-
phy shows that the dimer is held together by a
four-membered Li2O2 ring. It is likely that the solid
state structure of 2 also involves intermolecular associ-
ations involving lithium and oxygen but unfortunately
we were unable to grow a suitable single crystal of 2
for X-ray analysis to verify this. All attempts to ac-
quire solution NMR spectroscopic data for 2 were
unsuccessful. Instead, because of the extreme moisture
t
(PPh3)2 (6) through reaction with BuLi followed by
Me3SiCl to give the osmadisiloxane, Os(SiMe2OSi-
Me3)(j2-S2CNMe2)(CO)(PPh3)2 (8); (vii) the crystal
structures of 3–8.
2. Results and discussion
2.1. Preparation of Os(SiMe2OH)Cl(CO)(PPh3)2 (1)
t
and reaction of 1 with BuLi
Treatment of an orange-yellow solution of Os(Si-
Me2Cl)Cl(CO)(PPh3)2 in THF with an aqueous solution
of sodium hydroxide readily yields the yellow hydrolysis
product, Os(SiMe2OH)Cl(CO)(PPh3)2 (1) (see Scheme 1).
Scheme 1. Synthesis and reactions of a five-coordinate silanolate complex of osmium(II).

M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
1409
sensitivity of 2, data for the reprotonated compound 1
was always obtained.
and are isostructural. The overall geometry about os-
mium is similar to that of other five-coordinate osmium
silyl complexes, Os(silyl)Cl(CO)(PPh3)2 [7], and can be
described as tetragonal pyramidal with the angle be-
tween the silyl ligand and the chloride opened to
104.33(6)ꢀ (compound 3) and to 104.52(10)ꢀ (compound
4). The Os–Si distances are 2.3613(11) (compound 3)
2.2. Reactions of Os(SiMe2OLi)Cl(CO)(PPh3)2 (2)
with Me3SiCl and Me3SnCl and the crystal structures of
the products, Os(SiMe2OSiMe3)Cl(CO)(PPh3)2 (3)
and Os(SiMe2OSnMe3)Cl(CO)(PPh3)2 (4)
˚
and 2.3654(19) A (compound 4). These are at the long
end of the range of five-coordinate osmium–silicon
bond lengths, the average for 14 observations being
Treatment of 2 with either Me3SiCl or Me3SnCl
produces in high yield the orange complexes, Os-
(SiMe2- OSiMe3)Cl(CO)(PPh3)2 (3) or Os(SiMe2OSn-
Me3)Cl(CO) (PPh3)2 (4), respectively (see Scheme 1).
The physical properties for these two compounds are
closely similar, both showing m(CO) in the IR spectra
at 1892 cmꢀ1. This value is conspicuously lower than
the value measured (1910 cmꢀ1) for the related
hydroxysilyl compound 1, and can be attributed to
the electron-releasing properties of the Me3Si and
˚
2.3159 with a SD of 0.0283 A (Cambridge Crystallo-
graphic Data Base). In compound 3 the two Si–O dis-
tances are almost identical (Si(1)–O(2) = 1.658(3) and
˚
Si(2)–O(2) = 1.648(3) A). In compound 4 the Si–O dis-
˚
tance is shorter than those in 3 (Si–O(2) = 1.619(5) A),
˚
and Sn–O(2) = 1.986(4) A. The angles at the bridging
oxygen for 3 and 4 are rather similar (141.03(17)ꢀ and
136.1(3)ꢀ, respectively).
1
Me3Sn groups. In the H NMR spectra the resonances
for the osmium-bound SiMe2 groups are at 0.27 ppm
(for 3) and 0.19 ppm (for 4). The SiMe3 signal in 3 is
at ꢀ0.23 ppm and the SnMe3 signal in 4 is at 0.02
2.3. Preparation and crystal structure of Os(SiMe2Cl)-
(j2-S2CNMe2)(CO)(PPh3)2 (5)
2
ppm (with Sn satellites, JSnH = 56.8 Hz). Although
In Section 2.1 above it was shown that the chlorod-
imethylsilyl ligand in the five-coordinate complex,
Os(SiMe2Cl)Cl(CO)(PPh3)2, undergoes hydrolysis read-
ily. To examine the reactivity, towards hydrolysis, of
the chlorodimethylsilyl ligand when bound to osmium
in a six-coordinate environment, the complex Os(Si-
Me2Cl)-(j2-S2CNMe2)(CO)(PPh3)2 (5) was prepared.
Following the successful route found for the synthesis
of the closely related Ru(SiPh2Cl)(j2-S2CNMe2)-
(CO)(PPh3)2 [8], OsH(j2-S2CNMe2)(CO)(PPh3)2 was
treated with HSiMe2Cl to give pale yellow 5 in high
yield (see Scheme 2). The IR spectrum of 5 shows
compounds with LnM–Si–O–Si [3,1b] and LnM–Sn–
O–Si [6] linkages are known and structurally character-
ised, we are not aware of compounds containing the
LnM–Si–O–Sn linkage.
The crystal structures of 3 and 4 were determined
and the molecular geometries are shown in Figs. 1
and 2, respectively. Crystal data pertaining to these
structures and other structures reported in this paper
are presented in Table 1. Selected bond lengths and an-
gles for 3 and 4 are collected in Tables 2 and 3, respec-
tively. Both 3 and 4 crystallise as 0.5 benzene solvates
Fig. 1. Molecular geometry of Os(SiMe2OSiMe3)Cl(CO)(PPh3)2 (3).
Fig. 2. Molecular geometry of Os(SiMe2OSnMe3)Cl(CO)(PPh3)2 (4).

Table 1
Data collection and processing parameters for 3–8
3 Æ 0.5C6H6
4 Æ 0.5C6H6
5 Æ CH2Cl2
6
7 Æ H2O
8
Formula
C
964.60
45H48ClO2OsP2Si2
C45H48ClO2OsP2SiSn
1055.2
C43H44Cl3NOOsP2S2Si
1041.49
C42H43NO2OsP2S2Si
938.12
triclinic
C40H39NO5OsP2S2Si
958.07
triclinic
C45H51O2OsP2S2Si2
1010.31
triclinic
Molecular weight
Crystal system
Space group
monoclinic
C2/c
monoclinic
C2/c
monoclinic
C2/m
ꢀ
ꢀ
ꢀ
P1
P1
P1
˚
a (A)
35.3038(4)
10.6094(1)
24.5149(4)
35.2381(4)
10.6330(1)
24.5039(4)
28.0553(4)
15.1200(2)
11.4361(2)
11.3230(1)
13.2260(2)
16.0408(2)
99.665(1)
105.329(1)
110.852(1)
2071.54(4)
2
11.1660(2)
12.7355(2)
14.8788(3)
94.656(1)
107.200(1)
102.977(1)
1944.66(6)
2
11.3201(1)
12.3867(2)
17.4662(1)
107.753(1)
93.567(1)
97.475(1)
2299.14(4)
2
˚
b (A)
˚
c (A)
a (ꢀ)
b (ꢀ)
c (ꢀ)
110.641(1)
110.550(1)
96.699(1)
3
˚
V (A )
8592.68(19)
8
1.491
8562.04(17)
8
1.637
4829.40(13)
4
1.432
Z
Dcalc (g cmꢀ3
F(000)
)
1.504
940
3.32
1.636
956
3.54
1.459
1020
3.02
3880
3.19
4168
3.75
2080
3.01
l (mmꢀ1
)
Crystal size (mm)
2hmin,max (ꢀ)
Reflections
0.24 · 0.18 · 0.14
1.7, 26.4
39 136
0.18 · 0.16 · 0.12
1.78, 25.77
23 771
0.50 · 0.28 · 0.24
1.4, 26.4
27 924
0.36 · 0.22 · 0.16
1.7, 26.5
19 157
0.32 · 0.20 · 0.18
1.5, 26.5
18 381
0.38 · 0.20 · 0.18
1.8, 26.0
21 409
collected
Independent
reflections (Rint
Amin,max
8795 (0.0477)
0.514, 0.663
8165 (0.0473)
5113 (0.0143)
8308 (0.0144)
7952 (0.0146)
8908 (0.0150)
)
0.552, 0.662
1.16
0.314, 0.532
1.07
0.381, 0.619
1.04
0.397, 0.568
1.05
0.393, 0.612
1.04
Goodness-of-fit on F2 1.110
R (observed data)
R (all data)
Differential map
R1 = 0.0328; wR2 = 0.0661 R1 = 0.0466; wR2 = 0.0792 R1 = 0.0240; wR2 = 0.0685 R1 = 0.0156; wR2 = 0.0417 R1 = 0.0165; wR2 = 0.0425 R1 = 0.0192; wR2 = 0.0495
R1 = 0.0448; wR2 = 0.0706 R1 = 0.0685; wR2 = 0.0865 R1 = 0.0244; wR2 = 0.0688 R1 = 0.0164; wR2 = 0.0420 R1 = 0.0172; wR2 = 0.0428 R1 = 0.0205; wR2 = 0.0502
ꢀ0.81, +1.91
ꢀ1.06, +0.82
ꢀ1.28, +1.05
ꢀ0.50, +0.65
ꢀ0.68, +0.59
ꢀ1.01, +1.82
ꢀ3
˚
(min, max) (e A
)
P
P
R ¼ jjF oj ꢀ jF cjj= jF oj.
wR2 ¼
n
o
1=2
P
P
2
2
½wðF 2o ꢀ F c2Þ ꢁ= ½wðF 2oÞ ꢁ
.

M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
1411
Table 2
Table 3
˚
˚
Selected bond lengths (A) and angles (ꢀ) for 3
Selected bond lengths (A) and angles (ꢀ) for 4
Os–C(10)
Os–C(1)
Os–Si(1)
Os–P(2)
1.774(9)
1.774(7)
2.3613(11)
2.3648(9)
2.3876(10)
2.419(2)
2.449(3)
1.658(3)
1.872(5)
1.874(5)
1.648(3)
1.859(4)
1.861(4)
1.864(5)
Os–C(10)
Os–C(1)
Os–P(2)
Os–Si
1.753(14)
1.782(10)
2.3610(16)
2.3654(19)
2.3710(17)
2.410(4)
2.450(5)
1.619(5)
1.858(7)
1.866(8)
1.986(4)
2.110(7)
2.122(7)
2.123(7)
1.174(13)
1.077(15)
Os–P(1)
Os–Cl
Os–Cl0
Os–P(1)
Os–Cl
Os–Cl0
Si(1)–O(2)
Si(1)–C(3)
Si(1)–C(2)
Si(2)–O(2)
Si(2)–C(5)
Si(2)–C(4)
Si(2)–C(6)
Si–O(2)
Si–C(2)
Si–C(3)
Sn–O(2)
Sn–C(4)
Sn–C(5)
Sn–C(6)
O(1)–C(1)
O(10)–C(10)
C(1)–Os–Si(1)
C(1)–Os–P(2)
Si(1)–Os–P(2)
C(1)–Os–P(1)
Si(1)–Os–P(1)
P(2)–Os–P(1)
C(1)–Os–Cl
88.8(2)1
90.9(2)
94.57(4)
92.2(2)
C(10)–Os–C(1)
C(10)–Os–P(2)
C(1)–Os–P(2)
C(10)–Os–Si
C(1)–Os–Si
P(2)–Os–Si
C(10)–Os–P(1)
C(1)–Os–P(1)
P(2)–Os–P(1)
Si–Os–P(1)
C(10)–Os–Cl
C(1)–Os–Cl
P(2)–Os–Cl
Si–Os–Cl
178.3(7)
88.6(6)
90.7(3)
98.05(4)
167.05(4)
166.8(2)
93.0(6)
88.6(4)
Si(1)–Os–Cl
P(2)–Os–Cl
P(1)–Os–Cl
104.33(6)
87.37(5)
86.70(5)
93.21(6)
88.6(6)
91.7(3)
O(2)–Si(1)–C(3)
O(2)–Si(1)–C(2)
C(3)–Si(1)–C(2)
O(2)–Si(1)–Os
C(3)–Si(1)–Os
C(2)–Si(1)–Os
O(2)–Si(2)–C(5)
O(2)–Si(2)–C(4)
C(5)–Si(2)–C(4)
O(2)–Si(2)–C(6)
C(5)–Si(2)–C(6)
C(4)–Si(2)–C(6)
Si(2)–O(2)–Si(1)
104.20(18)
106.7(2)
105.3(3)
168.16(6)
98.43(6)
11.5(6)
112.39(10)
115.80(18)
111.68(16)
108.01(17)
110.90(18)
108.3(2)
166.8(4)
87.84(8)
104.52(10)
87.15(8)
157.8(6)
20.5(4)
P(1)–Os–Cl
C(10)–Os–Cl0
C(1)–Os–Cl0
P(2)–Os–Cl0
Si–Os–Cl0
P(1)–Os–Cl0
Cl–Os–Cl0
109.89(18)
110.8(2)
108.9(2)
88.29(11)
109.07(15)
89.95(11)
146.34(17)
108.9(3)
105.9(3)
104.1(4)
110.77(18)
110.5(3)
116.3(3)
107.6(3)
103.4(3)
112.6(3)
105.8(3)
111.3(3)
115.2(3)
136.1(3)
141.03(17)
O(2)–Si–C(2)
O(2)–Si–C(3)
C(2)–Si–C(3)
O(2)–Si–Os
C(2)–Si–Os
C(3)–Si–Os
O(2)–Sn–C(4)
O(2)–Sn–C(5)
C(4)–Sn–C(5)
O(2)–Sn–C(6)
C(4)–Sn–C(6)
C(5)–Sn–C(6)
Si–O(2)–Sn
m(CO) at 1888, 1869 cmꢀ1 (solid-state splitting). The H
NMR spectrum shows a singlet resonance at 0.29 ppm
for the equivalent methyl groups on silicon and signals
at 1.99 and 2.22 ppm for the two inequivalent methyl
groups of the dimethyldithiocarbamate ligand. The
31P NMR shows a singlet resonance at 8.6 ppm and
all of these data together are compatible with the
structure having mutually trans triphenylphosphine
ligands as depicted in Scheme 2 and as confirmed by
the X-ray crystal structure determination described
below.
1
˚
A, which is close to the average (2.4499 with SD
˚
0.0508 A) of 10 measured distances recorded in the
Cambridge Crystallographic Data Base for octahedral
osmium silyl complexes where silicon is 4-coordinate.
˚
The Si–Cl distance is 2.1223(16) A, which is long when
compared with the average of recorded Si–Cl distances
The molecular geometry of 5 is shown in Fig. 3 with
selected bond lengths and angles presented in Table 4.
The attachment of the bidentate dimethyldithiocarba-
mate ligand is unsymmetrical, with the Os–S distance
˚
greater when S is trans to the silyl ligand (2.5159(9) A)
and less when S is trans to the CO ligand (2.4622(10)
˚
˚
of 2.0579 A, SD 0.0435 A (Cambridge Crystallographic
Data Base). In contrast to the ‘‘flattening’’ of the organ-
ic substituents about silicon observed in the structure of
˚
A). This observation relates to the trans influence of
the silyl ligand. The Os–Si distance in 5 is 2.4021(11)

1412
M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
Scheme 2. Synthesis of a six-coordinate osmasilanol complex and conversion to an osmadisiloxane through the intermediacy of a proposed
osmasilanolate complex.
Ru(SiPh2Cl)(j2-S2CNMe2)(CO)(PPh3)2 [8] the angles
Os–Si–Me (116.52(8)ꢀ) and Os–Si–Cl (116.70(6)ꢀ) in 5
are closely similar.
2.4. Hydrolysis reactions of Os(SiMe2Cl)(j2-S2CN-
Me2)(CO)(PPh3)2 (5): preparation and crystal struc-
tures of Os(SiMe2OH)(j2-S2CNMe2)(CO)-(PPh3)2
(6) and Os[Si(OH)3](j2-S2CNMe2)(CO)-(PPh3)2 (7)
The hydrolysis procedure which was successful for
the conversion of Os(SiMe2Cl)Cl(CO)(PPh3)2 to Os(Si-
Me2OH)Cl(CO)(PPh3)2 (aqueous NaOH in THF at
room temperature) when applied to Os(SiMe2Cl)(j2-
S2CNMe2)(CO)(PPh3)2 gave only trace amounts of the
hydrolysis product Os(SiMe2OH)(j2-S2CNMe2)(CO)-
(PPh3)2 even with prolonged reaction times. Clearly,
the reactivity of the Si–Cl bond in the chlorodimethylsi-
lyl ligand is greatly reduced when it is bound in this
six-coordinate complex rather than the five-coordinate
complex, Os(SiMe2Cl)Cl(CO)(PPh3)2. Using aqueous
KOH in THF at a temperature of 60 ꢀC for 16 h produced
a 10% yield of Os(SiMe2OH)(j2-S2CNMe2)(CO)(PPh3)2
but the major product (36%) was, unexpectedly, the
trihydroxysilyl complex, Os[Si(OH)3](j2-S2CNMe2)-
(CO)-(PPh3)2 (7) (see Scheme 2). Another product of this
reaction proved to be the hydride, OsH(j2-S2CNMe2)-
(CO)-(PPh3)2 (20%). If this high temperature reaction
was left for a longer time the proportion of the hydride
complex formed was observed to increase. An alterna-
tive synthesis of 7 involves treatment of the hydroxydi-
methylsilyl complex 6 with KOH using the same
conditions as were successful for converting 5 to 7. It
Fig. 3. Molecular geometry of Os(SiMe2Cl)(j2-S2CNMe2)(CO)-
(PPh3)2 (5).

M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
1413
Table 4
˚
Selected bond lengths (A) and angles (ꢀ) for 5
Os–C(1)
Os–P(1)
Os–Si
1.845(4)
2.3884(7)
2.4021(11)
2.4622(10)
2.5159(9)
1.718(4)
Os–S(2)
Os–S(1)
S(1)–C(2)
S(2)–C(2)
Si–C(5)#1
Si–Cl(1)
O–C(1)
1.712(4)
1.962(2)
2.1223(16)
1.179(5)
1.333(5)
N–C(2)
C(1)–Os–P(1)
C(1)–Os–P(1)#1
P(1)–Os–P(1)#1
C(1)–Os–Si
89.87(2)
89.87(2)
165.18(4)
89.79(12)
97.407(18)
97.408(18)
175.73(12)
90.683(17)
90.683(17)
85.94(3)
P(1)–Os–Si
P(1)#1–Os–Si
C(1)–Os–S(2)
P(1)–Os–S(2)
P(1)#1–Os–S(2)
Si–Os–S(2)
Fig. 4. Molecular geometry of Os(SiMe2OH)(j2-S2CNMe2)-
(CO)(PPh3)2 (6).
C(1)–Os–S(1)
P(1)–Os–S(1)
P(1)#1–Os–S(1)
Si–Os–S(1)
113.68(12)
83.273(17)
83.273(17)
156.53(3)
70.59(3)
In this way Os(SiMe2OH)(j2-S2CNMe2)(CO)(PPh3)2 (6)
was produced in 83% yield. The ease with which this
hydrolysis occurs on silica gel, in contrast to the lack
of reactivity towards aqueous base discussed above, per-
haps suggests that the hydrolysis is ‘‘acid-catalysed’’ on
silica gel. The other product from this chromatographic
procedure did not contain a silyl ligand and proved to be
OsCl(j2-S2CNMe2)(CO)(PPh3)2 (yield 11%, see Scheme
2). Interestingly, an X-ray crystallographic study of this
chloride derivative [13] revealed that unlike the hydride
and silyl analogues, the chloride complex has a geometry
with Cl trans to CO and with mutually cis triphenyl-
phosphine ligands. The IR spectrum of Os(Si-
Me2OH)(j2-S2CNMe2)(CO)(PPh3)2 shows a m(CO) at
1859 cmꢀ1, significantly lower than the value for the
analogous chlorodimethylsilyl complex 5. m(OH) is seen
S(2)–Os–S(1)
C(5)#1–Si–C(5)
C(5)#1–Si–Cl(1)
C(5)–Si–Cl(1)
C(5)#1–Si–Os
C(5)–Si–Os
99.64(16)
102.44(8)
102.44(8)
116.52(8)
116.52(8)
116.70(6)
Cl(1)–Si–Os
Symmetry transformations used to generate equivalent atoms: #1 x,
ꢀy, z.
is unusual to observe cleavage of methyl groups from si-
lyl ligands bound to transition metals. However, it is not
without precedent in organosilicon chemistry, e.g., an
early report describes the reaction of Me3SiOSiMe3 with
KOH at high temperatures to give Me3SiOSiMe2(OH)
and CH4 [9]. A possibly related observation is that
Cp*RhH2(SiEt3)2 is converted to Cp*RhH2(SiEt3)[-
Si(OEt)3] through treatment with EtOH [10].
1
at 3643 cmꢀ1. In the H NMR spectrum a resonance at
There are very few compounds with trihydroxysilyl
functions which do not undergo rapid condensation
reactions to give three-dimensional framework solids
[11]. Stable examples, RSi(OH)3, usually have a very
bulky R group [12] but even then the solids are either
layers or cage-like structures with complex H-bond net-
works. A discrete Si(OH)3 group has been recognised as
0.51 ppm is assigned to the OH group. The crystal struc-
tures of these unusual hydroxysilyl complexes 6 and 7
are described below.
The molecular geometries of 6 and 7 are shown in
Figs. 4 and 5 with selected bond lengths and angles pre-
sented in Tables 5 and 6. The structures have mutually
trans triphenylphosphine ligands as depicted in Scheme
2. The attachment of the bidentate dimethyldithiocarba-
mate ligand is again unsymmetrical, with the Os–S dis-
tances being greater when S is trans to the silyl ligand
1
a ligand [3]. In the H NMR spectrum of the trihydrox-
ysilyl complex 7 a resonance is seen at 1.65 ppm inte-
grating for three protons. This is assigned to the
Si(OH)3 group. The structure of this novel trihydroxysi-
lyl complex is discussed below.
˚
(2.5449(5) for 6 and 2.5244(5) A for 7) and less when
S is trans to the CO ligand (2.4812(5) for 6 and
˚
2.4622(5) A for 7), reflecting the trans influence of the si-
lyl ligand. The Os–Si distance in 6 is 2.4334(5), and in 7
˚
is 2.3761(6) A. Both values are close to the average
We discovered, serendipidously, that a simple and
effective method for the hydrolysis of Os(SiMe2Cl)(j2-
S2CNMe2)(CO)(PPh3)2 involved passage of this com-
pound down a silica gel column using acetone as eluent.
˚
(2.4499 with SD 0.0508 A) of 10 measured distances

1414
M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
Table 6
Selected bond lengths (A) and angles (ꢀ) for 7
˚
Os–C(1)
Os–P(2)
Os–P(1)
Os–Si
1.839(2)
2.3692(5)
2.3741(5)
2.3761(6)
2.4622(5)
2.5244(5)
1.6591(17)
1.6596(17)
1.6722(18)
1.717(2)
Os–S(2)
Os–S(1)
Si–O(2)
Si–O(4)
Si–O(3)
S(1)–C(2)
S(2)–C(2)
O(1)–C(1)
N(1)–C(2)
1.712(2)
1.170(3)
1.320(3)
C(1)–Os–P(2)
C(1)–Os–P(1)
P(2)–Os–P(1)
C(1)–Os–Si
89.94(6)
89.78(6)
171.727(18)
92.48(7)
P(2)–Os–Si
P(1)–Os–Si
93.450(19)
94.823(19)
177.11(7)
89.999(17)
90.696(18)
84.643(19)
112.75(7)
86.134(17)
86.351(17)
154.76(2)
70.127(17)
106.53(9)
105.38(10)
104.52(10)
109.93(7)
110.87(6)
118.81(7)
C(1)–Os–S(2)
P(2)–Os–S(2)
P(1)–Os–S(2)
Si–Os–S(2)
Fig. 5. Molecular geometry of Os[Si(OH)3](j2-S2CNMe2)(CO)(PPh3)2
(7).
C(1)–Os–S(1)
P(2)–Os–S(1)
P(1)–Os–S(1)
Si–Os–S(1)
Table 5
S(2)–Os–S(1)
O(2)–Si–O(4)
O(2)–Si–O(3)
O(4)–Si–O(3)
O(2)–Si–Os
O(4)–Si–Os
O(3)–Si–Os
˚
Selected bond lengths (A) and angles (ꢀ) for 6
Os–C(1)
Os–P(1)
Os–P(2)
Os–Si
1.846(2)
2.3855(5)
2.3891(5)
2.4334(5)
2.4812(5)
2.5449(5)
1.7125(15)
1.875(2)
Os–S(2)
Os–S(1)
Si–O(2)
Si–C(2)
recorded in the Cambridge Crystallographic Data Base
for octahedral osmium silyl complexes where silicon is
4-coordinate. Significantly, the trihydroxysilyl derivative
has the shorter Os–Si distance. The Si–OH distance in 6
Si–C(3)
1.899(2)
S(1)–C(4)
S(2)–C(4)
O(1)–C(1)
N(1)–C(4)
1.7297(19)
1.7184(19)
1.182(2)
˚
is 1.7125(15) A and the three Si–OH distances in 7 are
1.330(3)
˚
1.6591(17), 1.6596(17), 1.6722(18) A. The Si–OH dis-
C(1)–Os–P(1)
C(1)–Os–P(2)
P(1)–Os–P(2)
C(1)–Os–Si
P(1)–Os–Si
88.37(6)
90.69(6)
tance in 6 is clearly longer than those in 7 and indeed
all these values are at the long end of the observed range
of Si–O distances (the average of all reported Si–O dis-
167.542(17)
91.47(6)
˚
tances for four-coordinate Si is 1.6295 (SD 0.0334) A,
Cambridge Crystallographic Data Base).
95.238(18)
97.205(18)
175.14(6)
91.853(16)
90.135(16)
83.674(17)
114.70(6)
83.313(16)
85.805(16)
153.680(17)
70.143(15)
100.25(10)
104.62(10)
105.36(12)
110.72(6)
113.25(8)
120.45(8)
P(2)–Os–Si
C(1)–Os–S(2)
P(1)–Os–S(2)
P(2)–Os–S(2)
Si–Os–S(2)
It is interesting to compare the Os–Si distance in 7
with the Os–Si distances measured in two other structur-
ally characterised trihydroxysilyl derivatives of osmium.
The Os–Si distance in five-coordinate Os[Si(OH)3]Cl-
C(1)–Os–S(1)
P(1)–Os–S(1)
P(2)–Os–S(1)
Si–Os–S(1)
˚
(CO)(PPh3)2 is 2.319(2) A [3] and the Os–Si distance in
the corresponding dicarbonyl derivative, Os[Si(OH)3]Cl-
˚
(CO)2(PPh3)2 is 2.464(1) A [14]. The value for 7 falls
S(2)–Os–S(1)
O(2)–Si–C(2)
O(2)–Si–C(3)
C(2)–Si–C(3)
O(2)–Si–Os
C(2)–Si–Os
C(3)–Si–Os
midway between these two extremes. The tightly-bound
trihydroxysilyl ligand in Os[Si(OH)3]Cl(CO)(PPh3)2
shows no hydrogen-bond interactions, but the trihyd-
roxysilyl ligand bound at the considerably longer dis-
tance in Os[Si(OH)3]Cl(CO)2(PPh3)2 has two hydroxy
functions on each silyl ligand involved in the formation

M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
1415
Table 7
Hydrogen bond distances (A) and angles (ꢀ) for 7
˚
O–Hꢂ ꢂ ꢂA
d(O–H) d(Hꢂ ꢂ ꢂA) d(Oꢂ ꢂ ꢂA)
\(O–Hꢂ ꢂ ꢂA)
145.6
O(3)–H(3)ꢂ ꢂ ꢂO(5)
0.84
O(2)–H(2)ꢂ ꢂ ꢂS(2)#1 0.84
2.05
2.63
2.60
2.789(4)
3.4263(18) 159.6
3.4264(17) 167.9
O(4)–H(4)ꢂ ꢂ ꢂS(2)#1 0.84
Symmetry transformations used to generate equivalent atoms: #1
ꢀx + 1, ꢀy, ꢀz + 1.
of a dimeric unit through hydrogen-bonds to a pair of
OH groups of the same ligand on an adjacent molecule.
Complex 7 crystallises with a single water molecule. Two
water molecules are associated with two molecules of
complex 7 through a hydrogen-bond network which in-
volves only one OH function of each of the trihydroxy-
silyl ligands. In addition, the other two hydroxy
functions form weak intermolecular hydrogen-bonds
to a S atom of another adjacent molecule. The dimen-
sions of these hydrogen-bond interactions for 7 are
presented in Table 7. The O–O distance for the SiO–
Fig. 6. Molecular geometry of Os(SiMe2OSiMe3)(j2-S2CNMe2)-
(CO)(PPh3)2 (8).
˚
Hꢂ ꢂ ꢂOH2 interaction is 2.789(4) A which lies in the
middle of the range observed for O–Hꢂ ꢂ ꢂO hydrogen
˚
bonding(2.48–2.90A)[15].TheO–Sdistancesfortheweak
˚
SiO–Hꢂ ꢂ ꢂS interactions are 3.4263(18) and 3.4264(17) A.
3. Conclusions
2.5. Conversion of Os(SiMe2OH)(j2-S2CNMe2)(CO)-
(PPh3)2 (6) to Os(SiMe2OSiMe3)(j2-S2CNMe2)-
(CO)(PPh3)2 (8) and the crystal structure of 8
It has been demonstrated that the reactivity towards
hydrolysis of chlorodimethylsilyl ligands bound to os-
mium(II) varies widely. Whereas the five-coordinate
complex Os(SiMe2Cl)Cl(CO)(PPh3)2 is readily hydro-
lysed at room temperature by aqueous base to Os(Si-
Me2OH)Cl(CO)(PPh3)2, the six-coordinate complex
Os(SiMe2Cl)(j2-S2CNMe2)(CO)(PPh3)2 resists base
hydrolysis at room temperature, and high temperature
reaction produces the trihydroxysilyl complex Os-
[Si(OH)3](j2-S2CNMe2)(CO)(PPh3)2. Os(SiMe2Cl)(j2-
S2CNMe2)(CO)(PPh3)2 is, however, readily hydrolysed
by chromatography on silica gel. Both hydroxydimeth-
ylsilyl complexes are deprotonated by tBuLi, giving sila-
nolate complexes but only Os(SiMe2OLi)Cl(CO)(PPh3)2
could be isolated as a solid. The silanolate complexes re-
act with Me3SiCl and Me3SnCl to give the expected
osmadisiloxane (3 and 8) and osmastannasiloxane (4)
complexes, respectively. Crystal structure determina-
tions of 3, 4, 5, 6, 7, and 8 verify the formulations of
the new compounds.
The single hydroxy function in Os(SiMe2OH)(j2-
S2CNMe2)(CO)(PPh3)2 is readily deprotonated through
t
treatment with BuLi (see Scheme 2). However, in this
case attempts to isolate the lithium silanolate complex
were unsuccessful. Nevertheless, treatment of the silano-
late prepared in situ with Me3SiCl gave (8) in high yield.
Complex 8 is also obtained, although in lower yield,
t
when BuLi is replaced by triethylamine. Colourless
crystals of 8 have m(CO) at 1861 cmꢀ1 in the IR spec-
trum. This is very close to the m(CO) value observed
for the immediate precursor, 6 (1859 cmꢀ1). The 1H
NMR spectrum shows singlet resonances for the Me3Si
function at ꢀ0.18 ppm and for the Me2Si function at 0.0
ppm. An X-ray crystal structure determination for 8 was
carried out and the molecular structure is depicted in
Fig. 6. Selected bond lengths and angles are presented
in Table 8. The overall arrangement of donor atoms
about the osmium is the same as described above for
complexes 5, 6 and 7. The Os–S distances and the Os–
Si distance in 8 are almost identical to those found for
the precursor complex, 6. The osmium-bound Si–O dis-
tance in 8 is 1.6779(19) and the terminal Si–O distance is
4. Experimental
4.1. General procedures and instruments
˚
1.6238(19) A. These values are significantly different, in
Standard laboratory procedures were followed as
have been described previously [16]. The compounds
Os(SiMe2Cl)Cl(CO)(PPh3)2 [5] and OsH(j2-S2CNMe2)(-
CO)(PPh3)2 [17] were prepared according to the litera-
ture methods.
contrast to the two corresponding values in complex 3,
which were almost identical. The Si–O–Si angle in 8 is
143.32(13)ꢀ, close to the values found in 3 and 4
(141.03(17)ꢀ and 136.1(3)ꢀ, respectively).

1416
M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
Table 8
yses were obtained from the Microanalytical Labora-
tory, University of Otago.
˚
Selected bond lengths (A) and angles (ꢀ) for 8
Os–C(1)
Os–P(2)
1.840(2)
2.3775(6)
2.3871(6)
2.4294(7)
2.4744(6)
2.5441(6)
1.716(3)
1.727(2)
1.6779(19)
1.895(3)
1.899(3)
1.6238(19)
1.815(4)
1.820(5)
1.906(5)
1.183(3)
1.332(3)
1.464(4)
1.470(4)
4.2. Preparation of Os(SiMe2OH)Cl(CO)(PPh3)2 (1)
Os–P(1)
Os–Si(1)
Os(SiMe2Cl)Cl(CO)(PPh3)2 (100 mg; 0.11 mmol) was
dissolved in THF (10 ml) containing aqueous sodium
hydroxide solution (0.2 M) (0.60 ml; 0.12 mmol) and
stirred for 5 min at room temperature. The THF was re-
moved under reduced pressure and dichloromethane (10
ml) then added to extract the compound. The dichloro-
methane solution was dried using anhydrous magnesium
sulfate and filtered. Hexane (10 ml) was added to effect
crystallisation of pure 1 as a yellow solid (74 mg,
76%). Anal. Calc. for C39H37ClO2OsP2Si: C, 54.89; H,
4.37. Found: C, 54.74; H, 4.34%. IR (cmꢀ1): 1910
Os–S(1)
Os–S(2)
S(1)–C(2)
S(2)–C(2)
Si(1)–O(2)
Si(1)–C(5)
Si(1)–C(6)
Si(2)–O(2)
Si(2)–C(8)
Si(2)–C(7)
Si(2)–C(9)
O(1)–C(1)
N(1)–C(2)
N(1)–C(4)
N(1)–C(3)
1
m(CO); other bands, 3626w m(OH); 899w, 829, 810. H
NMR (CDCl3, d): 7.64–7.37 (m, 30H, PPh3), 2.08 (br
s, 1H, SiOH, resonance disappears on addition of
D2O), 0.23 (s, 6H, Si(CH3)2). 31C NMR (CDCl3, d):
C(1)–Os–P(2)
C(1)–Os–P(1)
P(2)–Os–P(1)
C(1)–Os–Si(1)
P(2)–Os–Si(1)
P(1)–Os–Si(1)
C(1)–Os–S(1)
P(2)–Os–S(1)
P(1)–Os–S(1)
Si(1)–Os–S(1)
C(1)–Os–S(2)
P(2)–Os–S(2)
P(1)–Os–S(2)
Si(1)–Os–S(2)
S(1)–Os–S(2)
89.50(7)
89.93(7)
2,4
9.7 (s (SiCH3)2), 128.3 (t0, [16]
J
= 9.6 Hz, o-
J = 49.4 Hz, i-
CP
164.94(2)
89.75(8)
97.38(2)
CP
1,3
C6H5), 130.3 (s, p-C6H5), 132.3 (t0,
3,5
C6H5), 134.5 (t0,
J
= 10.8 Hz, m-C6H5), 183.2 (t,
CP
97.67(2)
2JCP = 9.0 Hz, CO). 31P NMR (CH2Cl2/CDCl3, d):
22.6. 29Si NMR (CH2Cl2/CDCl3, d): 23.27 (t, 2JSiP = 7.3
Hz).
174.09(8)
90.56(2)
91.54(2)
84.38(2)
115.53(8)
83.70(2)
82.97(2)
4.3. Preparation of Os(SiMe2OLi)Cl(CO)(PPh3)2 (2)
tBuLi in hexanes (1.5 M, 78 ll, 0.13 mmol) was added
by syringe to a yellow slurry of Os(SiMe2OH)Cl(-
CO)(PPh3)2 (100 mg, 0.12 mmol) in Et2O (20 ml) at 0
ꢀC. The mixture was stirred for 30 min, warmed to room
temperature and then stirred until gas evolution ceased
(ꢃ30 min). The volume of the resulting orange mixture
was reduced under vacuum and hexane was added to
complete precipitation of the orange product. This or-
ange solid was collected by filtration under N2 and
washed with pentane to give 2 (80 mg, 78%). Because
of extreme sensitivity towards water satisfactory elemen-
tal analyses for 2 were not obtained. Similarly, attempts
to record solution NMR spectra for this material always
gave data for the reprotonated species, i.e., compound 1.
However, a solid state IR spectrum was obtained. IR
(cmꢀ1): 1876s m(CO).
154.72(2)
70.34(2)
O(2)–Si(1)–C(5)
O(2)–Si(1)–C(6)
C(5)–Si(1)–C(6)
O(2)–Si(1)–Os
C(5)–Si(1)–Os
C(6)–Si(1)–Os
O(2)–Si(2)–C(8)
O(2)–Si(2)–C(7)
C(8)–Si(2)–C(7)
O(2)–Si(2)–C(9)
C(8)–Si(2)–C(9)
C(7)–Si(2)–C(9)
Si(2)–O(2)–Si(1)
105.43(12)
103.22(12)
103.26(15)
109.69(7)
119.78(10)
113.91(10)
115.07(17)
110.03(17)
114.2(3)
107.31(19)
103.5(3)
105.8(3)
143.32(13)
Infrared spectra (4000–400 cmꢀ1) were recorded as
Nujol mulls between KBr plates on a Perkin–Elmer Par-
agon 1000 spectrometer. NMR spectra were obtained on
a Bruker DRX 400 at 25 ꢀC. 1H, 31C, 31P, and 29Si NMR
spectra were obtained operating at 400.1 (1H), 100.6
(31C), 162.0 (31P), and 79.5 (29Si) MHz, respectively.
4.4. Preparation of Os(SiMe2OSiMe3)Cl(CO)(PPh3)2
(3)
1
Resonances are quoted in ppm and H NMR spectra
tBuLi in hexanes (1.5 M, 103 ll, 0.16 mmol) was
added by syringe to a yellow slurry of Os(SiMe2OH)Cl-
(CO)(PPh3)2 (132 mg, 0.15 mmol) in Et2O (20 ml) at 0
ꢀC. The mixture was stirred for 30 min, warmed to room
temperature and then stirred until gas evolution ceased
(ꢃ30 min). Me3SiCl (196 ll, 1.50 mmol) was then added
and the resulting reaction mixture stirred overnight. The
referenced to either tetramethylsilane (0.00 ppm) or
the proteo-impurity in the solvent (7.25 ppm for
CHCl3). 31C NMR spectra were referenced to CDCl3
(77.00 ppm), 31P NMR spectra to 85% orthophosphoric
acid (0.00 ppm) as an external standard, and 29Si NMR
spectra to tetramethylsilane (0.00 ppm). Elemental anal-

M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
1417
mixture was filtered and the volume of the orange fil-
trate reduced under vacuum. Hexane was then added
to effect precipitation of pure 3 as orange crystals (118
mg, 85%). Anal. Calc. for C42H45ClO2OsP2Si2: C,
54.50; H, 4.90. Found: C, 54.64; H, 5.00%. Crystals
for X-ray analysis were grown from benzene/hexane
and proved to be 0.5 benzene solvates (see Table 1).
solid. This was collected and recrystallised from dry
dichloromethane–hexane to give pure 5 (1.04 g, 93%).
Anal. Calc. for C42H42ClNOOsP2S2Si Æ 1/3CH2Cl2: C,
51.62; H, 4.37; N, 1.42. Found: C, 51.62; H, 4.42; N,
1.53%. The single crystal chosen for X-ray analysis
proved to be a 1.0 dichloromethane solvate. IR
(cmꢀ1): 1888 (s), 1869 m(CO). 1H NMR (CDCl3, d):
0.29 (s, 6H, Si(CH3)2), 1.99 (s, 3H, N(CH3)2), 2.22 (s,
3H, N(CH3)2), 7.30–7.31 (m, 18H, PPh3), 7.71–7.74
(m, 12H, PPh3). 31C NMR (CDCl3, d): 9.8 (Si(CH3)2),
36.7, 37.0 (N(CH3)2), 127.0 (br, o-C6H5), 129.3 (s, p-
1
IR (cmꢀ1): 1892 m(CO). H NMR (CDCl3, d): ꢀ0.23
(s, 9H, Si(CH3)3), 0.27 (s, 6H, Si(CH3)2), 7.32–7.61 (m,
30H, PPh3). 31C NMR (CDCl3, d): 2.1 (Si(CH3)3), 11.3
2,4
(Si(CH3)2), 128.0 (t0,
J
= 9.0 Hz, o-C6H5), 130.1 (s,
CP
1,3
2
p-C6H5), 132.4 (t0,
J
= 49.4 Hz, i-C6H5), 134.8 (t0,
C6H5), 135.1 (br, m-C6H5), 188.5 (t, JCP = 11.6 Hz,
CO), 208.9 (S2CNMe2).31P NMR (CDCl3, d): 8.6 (s).
CP
3,5
J
= 10.0 Hz, m-C6H5), 183.5 (t, 2JCP = 8.8 Hz, CO).
CP
4.5. Preparation of Os(SiMe2OSnMe3)Cl(CO)(PPh3)2
(4)
4.7. Preparation of Os(SiMe2OH)(j2-S2CNMe2)(CO)-
(PPh3)2 (6)
tBuLi in hexanes (1.5 M, 175 ll, 0.28 mmol) was
added by syringe to a yellow slurry of Os(SiMe2OH)Cl-
(CO)(PPh3)2 (224 mg, 0.26 mmol) in Et2O (40 ml) at 0
ꢀC. The mixture was stirred for 30 min, warmed to room
temperature and then stirred until gas evolution ceased
(ꢃ30 min). Me3SnCl (78.4 mg, 0.39 mmol) was then
added and the reaction mixture was stirred overnight.
The reaction mixture was filtered and the volume of
the orange filtrate was reduced under vacuum. Hexane
was then added to effect precipitation of pure 4 as or-
ange crystals (213 mg, 80%). Anal. Calc. for
C42H45ClO2OsP2SiSn: C, 49.64; H, 4.46. Found: C,
49.62; H, 4.76%. Crystals for X-ray analysis were grown
from benzene/hexane and proved to be 0.5 benzene sol-
A solution of Os(SiMe2Cl)(j2-S2CNMe2)(CO)(PPh3)2
(550 mg, 0.58 mmol) in a minimum quantity of CH2Cl2
was placed on a 10 cm column of silica gel and eluted
with acetone. After removal of solvent the resulting
crude product was redissolved in a minimum of CH2Cl2
and purified by column chromatography on silica gel
using acetone/hexane (v/v = 1:3) as eluant. The first col-
ourless fraction was collected and after solvent removal,
recrystallisation from CH2Cl2–EtOH gave pure 6 as a
white solid (450 mg, 83%). Anal. Calc. for C42H43NO2-
OsP2Si: C, 53.76; H, 4.58; N, 1.49. Found: C, 52.87;
H, 4.69; N, 1.63%. IR (cmꢀ1): 1859vs, m(CO), 3643w,
1
m(OH). H NMR (CDCl3, d): ꢀ0.03 (s, 6H, Si(CH3)2),
0.51 (br, 1H, OH, signal disappeared when D2O was
added to the NMR sample), 2.00 (s, 3H, N(CH3)2),
2.22 (s, 3H, N(CH3)2), 7.30–7.34 (m, 18H, PPh3),
7.70–7.74 (m, 12H, PPh3). 13C NMR (CDCl3, d): 6.9
1
vates (see Table 1). IR (cmꢀ1): 1892 m(CO). H NMR
2
(CDCl3, d): 0.02 (s with Sn satellites, JSnH = 56.8 Hz,
9H, Sn(CH3)3), 0.19 (s, 6H, Si(CH3)2), 7.31–7.65 (m,
30H, PPh3). 31C NMR (CDCl3, d): ꢀ2.90 (Si(CH3)2),
2,4
(s, Si(CH3)2), 36.7 (s, N(CH3)2), 37.1 (s, N(CH3)2),
2,4
1
11.90 (s with Sn satellites, JSnC = 435.5 Hz, Sn(CH3)3),
127.1 (t0,
J
CP
1,3
= 8.0 Hz, o-C6H5), 129.0 (s, p-C6H5),
= 49.2 Hz, i-C6H5), 135.1 (t0,
127.9 (t0,
J
CP
1,3
= 9.0 Hz, o-C6H5), 129.8 (s, p-C6H5),
= 49.4 Hz, i-C6H5), 134.8 (t0,
134.6 (t0,
J
= 9.0 Hz, m-C6H5), 189.8 (t, JCP = 11.6 Hz,
CP
3,5
2
133.0 (t0,
J
= 10.0 Hz, m-C6H5), 184.1 (t, JCP = 9.6 Hz,
J
CP
CP
3,5
2
J
CO), 209.3 (s, Me2NCS2). 31P NMR (CDCl3, d): 10.9
(s).
CP
CO). 29Si NMR (CH2Cl2/C6D6, d): 13.4 (t, JSiP = 6.6
2
Hz). 119Sn NMR (CH2Cl2/C6D6, d): 96.2 (s).
From the second colourless fraction obtained from
the chromatography procedure above, Os(j2-
S2CNMe2)Cl(CO)(PPh3)2 was obtained as a white solid,
(56 mg, 11%) (see discussion in Section 2.4).
4.6. Preparation of Os(SiMe2Cl)(j2-S2CNMe2)(CO)-
(PPh3)2 (5)
OsH(j2-S2CNMe2)(CO)(PPh3)2 (1.00 g, 1.15 mmol)
was placed in a 250 ml Schlenk tube and toluene (15
ml) and HSiMe2Cl (2.19 g, 23.0 mmol) added. The tube
was sealed, cooled in liquid nitrogen and then evacu-
ated. After warming to ambient temperature, the sealed
tube was shielded with a safety shield (CAUTION: pres-
sure increases as reaction proceeds) and heated in an oil
bath at 90 ꢀC for 18 h. During this time the yellow solu-
tion turned to an orange colour. After cooling, the sol-
vent volume was reduced under vacuum and hexane
added slowly to induce crystallisation of a pale yellow
4.8. Preparation of Os[Si(OH)3](j2-S2CNMe2)(CO)-
(PPh3)2 (7)
Os(SiMe2Cl)(j2-S2CNMe2)(CO)(PPh3)2 (140 mg,
0.15 mmol) in THF (15 ml) was treated with KOH
(200 mg, 3.6 mmol) in water (1 ml) at ca. 60 ꢀC for
16 h. All volatiles were removed under reduced pres-
sure and the resulting residue was taken up in CH2Cl2,
dried over anhydrous Na2SO4and then filtered. The
volume of the filtrate was reduced under vacuum and
this mixture placed on a silica gel column. Elution with

1418
M. Albrecht et al. / Inorganica Chimica Acta 358 (2005) 1407–1419
a mixture of acetone and hexane (1:3) gave rise to three
bands which were collected. The first band contained
Os(j2-S2CNMe2)H(CO)(PPh3)2 in ca. 20% yield. The
second band contained Os(SiMe2OH)(j2-S2CNMe2)-
(CO)(PPh3)2 in ca. 10% yield. From the third band a
colourless solid was obtained and recrystallised from
CH2Cl2/heptane to give pure 7 as colourless microcrys-
tals (50 mg, 36%). Anal. Calc. for C40H39NO4OsP2S2-
Si Æ H2O: C, 49.94; H, 4.30; N, 1.46. Found: C, 50.15;
H, 4.15; N, 1.67%. IR (cmꢀ1): 1877 (s) m(CO). 1H
NMR (CDCl3, d): 1.65 (b, 3H, OH), 1.97 (s, 3H,
N(CH3)2), 2.29 (s, 3H, N(CH3)2), 7.32–7.80 (m, 30H,
reflections using SADABS [19]. The structure was solved
by Patterson and Fourier methods and refined by full-
matrix least squares on F2 using programs SHELXS [20]
and SHELXL [21]. All non-hydrogen atoms were refined
anisotropically. Hydrogen atoms were located geometri-
cally and refined using a riding model. Compounds 3
and 4 are isostructural and both show disorder between
the chloride and carbonyl ligands. These ligands have
been refined using half-weighted atoms in the two posi-
tions. The final electron density map for compound 6
contained numerous electron density peaks, clustered
in one region of the unit cell. These could not sensibly
be resolved into a molecule and presumably represent
a severely disordered heptane molecule. This density
was removed using the ꢀsqueezeꢁ function of PLATON
[22] before the final refinement. Compound 7 crystallises
with a molecule of water. The hydrogen atoms on this
water molecule could not be located and are, presuma-
bly, disordered. There are a number of hydrogen bonds
present in this structure. Two of the hydroxyl groups on
the silicon atom form hydrogen bonds to a single sulfur
atom on an adjacent molecule and the third hydroxyl
group forms a hydrogen bond to the water molecule
(see Table 7). Crystal data and refinement details are gi-
ven in Table 1.
PPh3). 31C NMR (CDCl3, d): 36.6 (s, N(CH3)2), 36.9
2,4
(s, N(C H3)2), 127.3 (t0,
J
= 9.0 Hz, o-C6H5),
= 50.4 Hz, i-it
CP
CP
1,3
129.4 (s, p-C6H5), 134.2 (t0,
J
3,5
C6H5), 134.9 (t0,
J
= 9.0 Hz, m-C6H5), 188.1 (t,
CP
2JCP = 11.6 Hz, CO), 209.5 (s, Me2NCS2). 31P NMR
(CDCl3, d): 10.8 (s).
4.9. Preparation of Os(SiMe2OSiMe3)(j2-S2CNMe2)-
(CO)(PPh3)2 (8)
A
solution
of
Os(SiMe2OH)(j2-S2CNMe2)-
(CO)(PPh3)2 (94 mg, 0.1 mmol) in THF (10 ml) was
t
cooled to ca. ꢀ40 ꢀC, and BuLi (0.120 ml of a 1.5 M
solution in pentane, 0.18 mmol) was added dropwise
to this solution. The resulting mixture was allowed to
warm to room temperature and stirred for 2 h. Me3SiCl
(0.100 ml, 0.8 mmol) was added and the reaction mix-
ture stirred overnight. All the volatiles were removed un-
der reduced pressure and the residue purified by column
chromatography on silica gel. Using CH2Cl2 as eluent, a
colourless band was collected and the white solid ob-
tained from this band, after recrystallisation from
CH2Cl2/EtOH, gave pure 8 as colourless crystals (78
mg, 77%). Anal. Calc. for C45H51NO2OsP2Si2: C,
53.50; H, 5.09; N, 1.39. Found: C, 53.53; H, 5.27; N,
1.68%. IR (cmꢀ1): 1861vs, m(CO). 1H NMR (CDCl3,
d): ꢀ0.18 (s, 9H, Si(CH3)3), 0.00 (s, 6H, Si(CH3)2),
2.02 (s, 3H, N(CH3)2), 2.27 (s, 3H, N(CH3)2), 7.28–
7.76 (m, 30H, PPh3). 13C NMR (CDCl3, d): 2.78 (s,
5. Supplementary material
Crystallographic data (excluding structure factors)
for the structures reported have been deposited with
the Cambridge Crystallographic Data Centre as Supple-
mentary Publication Nos. 241813–241818 for 3, 4, 5, 6,
7, and 8, respectively. Copies of this information can be
obtained free of charge from the Director, CCDC, 12
Union Road, Cambridge, CB2 1EZ, UK (fax: +44
1223 336 033; e-mail: deposit@ccdc.cam.ac.uk or
www:http://www.ccdc.cam.ac.uk).
Acknowledgements
Si(CH3)3), 9.20 (s, Si(CH3)2), 36.89 (s, N(CH3)2), 37.13
2,4
(s, N(CH3)2), 126.9 (t0,
J
= 9.4 Hz, o-C6H5), 128.9
CP
We thank the Marsden Fund, administered by the
Royal Society of New Zealand, for supporting this work
and for granting Postdoctoral Fellowships to M.A. and
G.-L.L and the Croucher Foundation for granting a
Postdoctoral Fellowship to H.-W.K. We thank the Uni-
versity of Auckland Research Committee for partial
support of this work through grants-in-aid.
3,5
J
(s, p-C6H5), 135.0 (t0,
= 10.2 Hz, m-C6H5), 189.8
CP
2
(t, JCP = 12.2 Hz, CO), 209.8 (s, Me2NCS2). 31P
NMR (CDCl3, d): 12.1 (s).
4.10. X-ray crystal structure determinations for com-
plexes 3, 4, 5, 6, 7, and 8
X-ray data collection was by Siemens SMART dif-
fractometer with a CCD area detector using graphite
˚
monochromated Mo Ka radiation (k = 0.71073 A) at
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