1,1,2,2-tetramethyl-1,2-bis(phenylthiomethyl)disilane, a flexible ligand for the construction of macrocyclic, mesocyclic, and bridged dithioether complexes. Synthesis of the bis-silylated olefins Z-(PhSCH2)Me 2SiC(H)=C(Ar)SiMe2(CH2SPh) by catalytic activation of the Si-Si bond

Article abstract of DOI:10.1021/om0489812

The functionalized disilane (PhSCH₂)Me₂SiSiMe ₂(CH₂SPh) (1) has been prepared and coordinated as a dithioether ligand on [PtCl₂(PhCN)₂] to afford the fluxional seven-membered chelate complex cis-[PtCl₂{(PhSCH ₂)₂Si₂Me₄}] (2a). After metathesis reaction of 2a with NaI the diiodo derivative cis-[PtI₂{(PhSCH ₂)₂Si₂Me₄}] (2b) was obtained. Treatment of [Re(μ-Br)(CO)₃THF]₂ with 1 equiv of 1 yields the bromo-bridged dinuclear complex fac-[{Re(μ-Br)(CO) ₃}₂{μ-(PhSCH₂)₂Si ₂Me₄}] (5), which is spanned by 1 forming a 10-membered mesocycle. Addition of a further equivalent of 1 yields the dinuclear macrocyclic compound fac-[{ReBr(CO)₃}₂{μ-(PhSCH ₂)₂Si₂Me₄}₂] (4), forming a 14-membered ring system. The chloro-bridge of [RuCI(μ-Cl)(CO) ₃]₂ is cleaved by 1 to give the dinuclear compound fac-[{RuCl₂(CO)₃}₂{μ-(PhSCH ₂)₂Si₂Me₄}] (6), in which the two metal fragments are linked by the thioether functions. In the presence of catalytic amounts of Pd(OAc)₂/CNR, the Si-Si bond of 1 is cleaved and addition across the triple bond of phenylacetylene or p-tolylacetylene affords the bis-silylated olefins Z-(PhSCH₂)Me₂SiC(H)=C(Ar) SiMe₂(CH₂SPh) (7a Ar = Ph; 7b Ar = p-Tol). The new compounds have been studied by multinuclear NMR techniques; the crystal structures of 2a, 2b, 4, 5, 6, and 7a have been determined by X-ray diffraction studies.

Full text of DOI:10.1021/om0489812

1472
Organometallics 2006, 25, 1472-1479
1,1,2,2-Tetramethyl-1,2-bis(phenylthiomethyl)disilane, a Flexible
Ligand for the Construction of Macrocyclic, Mesocyclic, and
Bridged Dithioether Complexes. Synthesis of the Bis-silylated
Olefins Z-(PhSCH2)Me2SiC(H)dC(Ar)SiMe2(CH2SPh) by Catalytic
Activation of the Si-Si Bond
Harmel N. Peindy,† Fabrice Guyon,† Isabelle Jourdain,† Michael Knorr,*,†
Daniel Schildbach,‡ and Carsten Strohmann*,‡
Laboratoire de Chimie des Mate´riaux et Interfaces, Faculte´ des Sciences et des Techniques, UniVersite´ de
Franche-Comte´, 16, Route de Gray, 25030 Besanc¸on Cedex, France, and Institut fu¨r Anorganische Chemie
der UniVersita¨t Wu¨rzburg, Am Hubland, D-97074, Wu¨rzburg, Germany
ReceiVed December 23, 2004
The functionalized disilane (PhSCH2)Me2SiSiMe2(CH2SPh) (1) has been prepared and coordinated as
a dithioether ligand on [PtCl2(PhCN)2] to afford the fluxional seven-membered chelate complex cis-
[PtCl2{(PhSCH2)2Si2Me4}] (2a). After metathesis reaction of 2a with NaI the diiodo derivative
cis-[PtI2{(PhSCH2)2Si2Me4}] (2b) was obtained. Treatment of [Re(µ-Br)(CO)3THF]2 with 1 equiv of 1
yields the bromo-bridged dinuclear complex fac-[{Re(µ-Br)(CO)3}2{µ-(PhSCH2)2Si2Me4}] (5), which is
spanned by 1 forming a 10-membered mesocycle. Addition of a further equivalent of 1 yields the dinuclear
macrocyclic compound fac-[{ReBr(CO)3}2{µ-(PhSCH2)2Si2Me4}2] (4), forming a 14-membered ring
system. The chloro-bridge of [RuCl(µ-Cl)(CO)3]2 is cleaved by 1 to give the dinuclear compound fac-
[{RuCl2(CO)3}2{µ-(PhSCH2)2Si2Me4}] (6), in which the two metal fragments are linked by the thioether
functions. In the presence of catalytic amounts of Pd(OAc)2/CNR, the Si-Si bond of 1 is cleaved and
addition across the triple bond of phenylacetylene or p-tolylacetylene affords the bis-silylated olefins
Z-(PhSCH2)Me2SiC(H)dC(Ar)SiMe2(CH2SPh) (7a Ar ) Ph; 7b Ar ) p-Tol). The new compounds have
been studied by multinuclear NMR techniques; the crystal structures of 2a, 2b, 4, 5, 6, and 7a have been
determined by X-ray diffraction studies.
Si-Si σ-bond possesses a high-lying HOMO and a low-lying
LUMO. This energetic feature of the frontier orbitals, which
has also been theoretically investigated, confers properties that
are similar to the CdC bond.13,14 A recent DFT computational
study on the bis-silylation of acetylenes catalyzed by Pd
complexes has shown that the oxidative addition is an easy
process with almost no barrier.15 The isolation of some reaction
intermediates such as bis-silyl complexes or silylated alkenyl
complexes allows conceiving a catalytic cycle involving the
following steps: (i) oxidative addition of the Si-Si bond across
a metal center, (ii) subsequent insertion of the unsaturated
substrate into a M-Si bond, and (iii) finally reductive elimina-
tion of the bis-silylated substrate (Scheme 1).16,17
Introduction
The catalytic cleavage of the Si-Si bond of disilanes by
transition metals is an elegant route for the bis-silylation (double
silylation) of unsaturated organic substrates such as alkynes,
olefins, isonitriles, and aldehydes.1-11 As catalysts, Pd(PPh3)4,
Pd(CNR)2, Pd(OAc)2, [Pt(C2H4)(PPh3)2], the mutual syn-ar-
rangement of the two SiCH2SPh substituents, or [RuHCl(CO)-
(PPh3)3]12 are often employed to activate the disilane, whose
* To whom correspondence should be addressed. E-mail:
michael.knorr@univ-fcomte.fr; mail@carsten-strohmann.de.
† Universite´ de Franche-Comte´.
‡ Institut fu¨r Anorganische Chemie der Universita¨t Wu¨rzburg.
(1) (a) Okinoshima, H.; Yamamoto, K.; Kumada, M. J. Organomet.
Chem. 1975, 86, C27. (b) Sakurai, H.; Kamiyama, Y.; Nakadeira, Y. J.
Am. Chem. Soc. 1975, 97, 931.
In the context of our interest on organosilicon compounds18-20
and transition metal silyl complexes,21-25 we have recently
prepared a series of organosilanes functionalized by phenyl-
(2) (a) Watanabe, H.; Kobayashi, M.; Higuchi, K.; Nagai, Y. J.
Organomet. Chem. 1980, 186, 51. (b) Watanabe, H.; Kobayashi, M.; Saito,
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2002, 124, 5506.
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(b) Kang, S. O.; Lee, J.; Ko, J. Coord. Chem. ReV. 2002, 231, 47.
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Strohmann, C.; Schildbach, D. In The Chemistry of Organolithium
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10.1021/om0489812 CCC: $33.50 © 2006 American Chemical Society
Publication on Web 02/11/2006

Synthesis of the Bis-silylated Olefins
Organometallics, Vol. 25, No. 6, 2006 1473
Scheme 1. Catalytic Cycle for the Bis-silylation of
Unsaturated Organic Substrates
Scheme 2
Metathesis reaction in the presence of NaI in a CH2Cl2/acetone
mixture transformed 2a into the orange-red derivative cis-
[PtI2{(PhSCH2)2Si2Me4}] (2b) (Scheme 2).
thiomethyl substituents such as Ph2Si(PhSCH2)2 or Me(H)Si-
(PhSCH2)2 and coordinated these ligands via their thioether
function or via a covalent M-Si bond on Pt and Re.26 In light
of a potential application for bis-silylation reactions, we have
now extended our research on the compound 1,1,2,2-tetramethyl-
1,2-bis(diphenylthiomethyl)disilane (1). In addition to an oxida-
tive addition of the Si-Si bond across a low-valent metal center,
the two thioether functions of this disilane may also interact
with soft metal centers. We have therefore undertaken a study
to evaluate first the coordination chemistry of this promising
hybrid ligand system 1 on various transition metals before
exploiting its potential for catalytic or stoichiometric bis-
silylation reactions. A point of interest was the evaluation of
the influence of the incorporation of a disilane motif in the chain
and the comparison with dithioether ligand systems of the type
RS(CH2)nSR. Due to its flexibility, this ligand system may a
priori adopt chelating and bridging bonding modes. The
syntheses and the crystal structures of some dithioether com-
plexes ligated by 1 are presented in this paper together with
some results on the catalytic activation of the Si-Si bond of 1
in the presence of 1-alkynes. In addition to multinuclear NMR
studies, the molecular structure of the resulting bis-silylated
olefins has also been determined.
Like numerous literature-known dithioether complexes, also
2a and 2b exhibit temperature-dependent 1H NMR spectra. The
study of inversion processes at the sulfur atoms in solution
giving rise to meso- and dl-isomers has been the topic of several
publications; therefore we have not studied this phenomenon
in detail.28-30 It is known that the relative invertomer populations
are a function of a sensitive balance of factors such as the nature
of the metal, substituents on sulfur, ring size, coordinated ligand,
and temperature. We have recently examined the pyramidal
inversion of the related six-membered chelate complex cis-
[PtCl2{(PhSCH2)2SiPh2}].26 In the case of 2a, the proton NMR
spectrum recorded in CDCl3 at 298 K consists of two mutually
coupled doublets (2JH,H ) 11.8 Hz) at δ 3.36 and 2.28; the latter
display an additional 3JPt,H coupling of 52 Hz. Apart from these
methylene resonances, two distinct singlets at δ 0.54 and 0.41
are assigned to the Si-methyl substituents. At 323 K, the four
methyl groups give rise to a single resonance at δ 0.55 and the
methylene protons have lost their splitting and appear as broad
humps at δ 3.34 and 2.37. The observation that the coalescence
temperature for the inversion process of square-planar complexes
[MX2{RS(CH2)nSR}] (M ) Pd, Pt; X ) Cl, Br, I) falls in the
order Cl > Br > I has been rationalized by the trans-influence
of the halide on the strength of the M-S bond.28 In agreement
with the crystallographic data (see below), this interpretation
may also account for the signal form of the proton NMR
spectrum of 2b. This exhibits already at 298 K a very broad
singlet at δ 0.51 and two extreme broadened resonances at δ
2.32 and 3.53 due to the methylene protons. At 318 K, the latter
signals have almost disappeared in the baseline, and the four
Si-CH3 groups now give rise to a sharpened singlet at δ 0.54.
Consistent with a dynamic behavior is also the temperature
dependency of the 195Pt{1H} NMR spectrum of 2a (see
Supporting Information). At 298 K, three broadened resonances
in an approximate 1:2:1 ratio are observed at δ ) -1844,
-1847, and -1850 ppm. Raising the temperature to 323 K
causes the appearance of a narrow singlet at δ ) -1846. In
addition, a second less intense resonance is now found at δ )
-1825. The 29Si NMR INEPT spectrum of 2a (recorded at 298
K) consists of a broad singlet, which appears slightly downfield
shifted with respect to noncoordinated 1 (δ -14.8 vs -16.7).
Crystal Structures of 2a and 2b. Suitable single crystals of
the two compounds were grown from CH2Cl2/hexane. 2a shows
a highly disordered phenyl substituent on S(1). The disordered
carbon atoms were refined on split positions. The molecular
Results and Discussion
Synthesis of 1 and Coordination on Platinum as Chelating
Dithioether Ligand. The functionalized disilane 1 was prepared
by reaction of [(phenylthio)methyl]lithium with dichlorotetra-
methyldisilane in hexane/Et2O and isolated in 78% yield as a
colorless solid. The detailed multinuclear NMR data of air-stable
1,1,2,2-tetramethyl-1,2-bis(diphenylthiomethyl)disilane (1) are
presented in the Experimental Section.27 Upon reaction of [PtCl2-
(PhCN)2] with a slight excess of 1 in dichloromethane at 303
K, the stable yellow square-planar chelate complex cis-
[PtCl2{(PhSCH2)2Si2Me4}] (2a) was isolated as sole product.
(22) Knorr, M.; Strohmann, C.; Braunstein, P. Organometallics 1996,
15, 5653.
(23) Braunstein, P.; Knorr, M.; Stern, C. Coord. Chem. ReV. 1998, 178-
180, 903.
(24) Braunstein, P.; Knorr, M.; Reinhard, G.; Schubert, U.; Sta¨hrfeldt,
T. Chem. Eur. J. 2000, 6, 4265.
(25) (a) Knorr, M.; Strohmann, C. Eur. J. Inorg. Chem. 2000, 241. (b)
Jayaswal, M. N.; Peindy, H. N.; Guyon, F.; Knorr, M.; Avarvari, N.;
Fourmigue´, M. Eur. J. Inorg. Chem. 2004, 2646. (c) Guyon, F.; Jayaswal,
M. N.; Peindy, H. N.; Hameau, A.; Knorr, M.; Avarvari, N. Synth. Met.
2005, in press.
(26) (a) Knorr, M.; Guyon, F.; Jourdain, I.; Kneifel, S.; Frenzel, J.;
Strohmann, C. Inorg. Chim. Acta 2003, 350, 455. (b) Knorr, M.; Guyon,
F.; Peindy, H.; Sachdev, H.; Strohmann, C. Z. Anorg. Allg. Chem. 2004,
630, 1955.
(27) The synthesis of the related disilane (PhS)2CHMe2SiSiMe2CH(SPh)2
has been recently published: Shimizu, M.; Hiyama, T.; Matsubara, T.;
Yamabe, T. J. Organomet. Chem. 2000, 611, 12.
(28) (a) Hartley, F. R.; Murray, S. G.; Levason, W.; Soutter, H. E.;
McAuliffe, C. A. Inorg. Chim. Acta 1979, 35, 265. (b) Marangoni, G.;
Pitteri, B.; Bertolasi, V.; Gilli, P. Inorg. Chim. Acta 1995, 234, 173.
(29) Abel, E. W.; Bhargava, S. K.; Orrell, K. G. Progr. Inorg. Chem.
1984, 32, 1.
(30) Su¨nkel, K.; Blum, A. Z. Naturforsch. 1995, 1307.

1474 Organometallics, Vol. 25, No. 6, 2006
Peindy et al.
Figure 1. Molecular structures of 2a (only one of two disordered atoms for C8-C12 shown) and 2b in the solid state (Schakal plot).
Selected bond lengths (Å) and angles (deg) 2a: C(1)-S(1) 1.803(9), C(1)-Si(1) 1.909(9), C(2)-S(2) 1.800(9), C(2)-Si(2) 1.923(11),
Cl(1)-Pt 2.318(2), Cl(2)-Pt 2.311(2), Pt-S(2) 2.267(2), Pt-S(1) 2.281(2), Si(1)-Si(2) 2.357(4); S(2)-Pt-S(1) 91.15(8), Cl(2)-Pt-Cl-
(1) 90.04(9); 2b: C(3)-S(1) 1.790(6), C(3)-Si(1) 1.899(6), C(12)-S(2) 1.788(6), C(12)-Si(2) 1.898(6), I(1)-Pt 2.6004(5), I(2)-Pt 2.6042-
(8), Pt-S(2) 2.2773(12), Pt-S(1) 2.2990(14), Si(1)-Si(2) 2.348(2); S(2)-Pt-S(1) 89.48(5), I(1)-Pt-I(2) 91.771(18).
structure of 2a reveals a square-planar coordination sphere
around the Pt(II) atom and forms a seven-membered chelate
ring as shown in Figure 1. The root-mean-square deviation from
the plane defined by Cl(1)-Cl(2)-Pt-S(1)-S(2) amounts to
0.011 Å. The closely related platinum complex cis-[PtCl2{PhS-
(CH2)4SPh}] ligated by a 1,4-bis(phenylthio)butane ligand is
known in the literature, but (apart from IR data) no structural
data are available.31 2a is therefore best compared to cis-
[PtCl2{(PhSCH2)2SiPh2}] forming a six-membered chelate
complex.26 The Pt atom is ligated by two chloro ligands in a
cis-arrangement [Cl(1)-Pt-Cl(2) ) 90.02(8)°]. The Pt-S(1)
and Pt-S(2) bond distances of 2.281(1) and 2.267(2) Å parallel
those of [PtCl2{(PhSCH2)2SiPh2}] [2.281(2) and 2.271(2) Å].
The average Pt-Cl bond length of 2a [2.315 Å] is somewhat
shorter that of the diphenyl[bis(phenylthio)methyl]silane deriva-
tive [2.321 Å]. In contrast to the latter complex, where the
phenyl substituents of the sulfur atoms are syn-orientated with
respect to the chelate ring (corresponding to a meso-conforma-
tion), the phenyl groups of 2a and 2b are anti-orientated in the
solid state (dl invertomer). The S(1)-Pt-S(2) angle of 2b is
more acute than in 2a [89.48(5)° vs 91.15(8)°], probably due
to the stronger thermodynamic trans-influence of iodide com-
pared to chloride, and the average Pt-S distance of 2b is slightly
longer than that of 2a [2.288 vs 2.274 Å]. The same tendency
of the Pt-S bond lengths of the series [PtX2{PhS(CH2)2SPh}]
(X ) Cl, Br, I) has been discussed in detail by Marangoni et
al.28b
Pr}] and [Pd(CH3){PriS(CH2)3SiPr}][BAr4] has demonstrated
the ability of these dithioether complexes to catalyze the
copolymerization of CO/ethylene leading to polyketones.33
Tanaka and Ito have demonstrated that Pt(II) and Pt(IV) silyl
complexes are accessible through oxidative addition of a Si-
Si bond to the Pt center.34 With the aim to prepare a bis(silyl)
complex [Pt(PEt3)2{SiCH2SPh}2], cis-[PtCl2(PEt3)2] was treated
with 2 equiv of 1 in refluxing toluene overnight. Instead of the
hoped-for oxidative addition of the Si-Si bond across platinum,
quantitative cis-trans isomerization of the starting material
occurred to afford trans-[PtCl2(PEt3)2], as evidenced by NMR
and an X-ray diffraction study of the isolated yellow-greenish
crystals.
Synthesis of Cyclic Rhenium Complexes with 1 Acting as
Bridging Dithioether Ligand. Previous studies have shown that
dithioether RS(CH2)nSR react with hexacarbonyl-µ-dihalogeno-
bis(tetrahydrofuran)dirhenium(I)35 to form mononuclear com-
plexes when n ) 2 or 329,39,40 and dinuclear complexes when n
) 0.36,37 In a previous paper, we have also demonstrated that
treatment of the dimeric compound [Re(µ-Br)(CO)3THF]2 with
Ph2Si(PhSCH2)2 results in formation of the conformational rigid
dithioether complex fac-[Re(Br)(CO)3{(PhSCH2)2SiPh2}], che-
lated by the dithioether ligand forming a six-membered cycle.26
Attempting to isolate a similar stable chelate compound, a
solution of [Re(µ-Br)(CO)3THF]2 in CH2Cl2 was reacted with
2 equiv of 1 at 298 K. Surprisingly, the stable white solid
obtained was identified unambiguously by an X-ray study (see
below) as the macrocyclic compound fac-[{ReBr(CO)3}2{µ-
(PhSCH2)2Si2Me4}2] (4). The dithioether acts as a bridging
ligand connecting the two rhenium atoms, thus forming a 14-
Alkylation of 2a. A convenient method to alkylate [PtCl2-
(1,5-cyclooctadiene)] is transmetalation by tetramethylstannane
to produce [PtCl(CH3)(1,5-cyclooctadiene)] and Me3SnCl.32
Similarly, a solution of 2a reacts gradually after addition of
1.5 equiv of Me4Sn and stirring for 2 days at ambient
temperature. In the dark dried residue, the characteristic smell
of Me3SnCl is noticeable. Although we could not obtain a
satisfactory elemental analysis due to the presence of a small
amount of side-products, which could not be removed by
recrystallization, the formation of [PtCl(CH3){(PhSCH2)2Si2-
Me4}] (3) is evidenced by the proton NMR spectrum. As
expected for a Pt-bound methyl group, a singlet at δ 0.91 with
(33) Bastero, A.; Claver, C.; Ruiz, A. Catal. Lett. 2002, 82, 85.
(34) (a) Yamashita, H.; Tanaka, M.; Goto, M. Organometallics 1992,
11, 3227. (b) Suginome M.; Oike, H.; Shuff, P. H.; Ito, Y. J. Organomet.
Chem. 1996, 521, 405.
(35) Vitali, D.; Calderazzo, F. Gazz. Chim. Ital. 1972, 102, 587.
(36) Bernal, I.; Atwood, J. L.; Calderazzo, F.; Vitali, D. Gazz. Chim.
Ital. 1976, 106, 971.
(37) Bernal, I.; Atwood, J. L.; Calderazzo, F.; Vitali, D. Isr. J. Chem.
1977, 15, 153.
(38) (a) Gibson, V. C.; Long, N. J.; White, A. J. P.; Williams, C. K.;
Williams, D. J. Organometallics 2000, 19, 4425. (b) Gibson, V. C.; Long,
N. J.; Long, R. J.; White, A. J. P.; Williams, C. K.; Williams, D. J.; Grigiotti,
E.; Zanello, P. Organometallics 2004, 23, 957.
2
a JPt-H coupling of 73 Hz is observed. For comparison, the
methyl resonance of [PtCl(CH3)(1,5-cod)] gives rise to a singlet
at δ 0.93 with a 3JPt-H coupling of 71 Hz. Note that a recent
study on the methylated Pd complex [PdCl(CH3){PriS(CH2)3Si-
(39) (a) Alberto, R.; Schibli, R.; Angst, D.; Schubiger, P. A.; Abram,
U.; Abram, S.; Kaden, T. A. Transition Met. Chem. 1997, 22, 567. (b)
Pietzsch, H.-J.; Gupta, A.; Reisgys, M.; Drews, A.; Seifert, S.; Syhre, R.;
Spies, H.; Alberto, R.; Abram, U.; Schubiger, P. A.; Johannsen, B.
Bioconjugate Chem. 2000, 11, 414.
(31) Munroe, V. G.; Peach, M: E.; Stiles, D. A. Inorg. Nucl. Chem.
Lett. 1969, 5, 977.
(32) Eaborn, C.; Kundu, K.; Pidcock, A. J. Chem. Soc., Dalton Trans.
1981, 933.
(40) Abel, E. W.; Orrell, K. G.; Poole, M.; Sik, V.; Hursthouse, M. B.;
Mazid, M. A. Polyhedron 1995, 14, 585.

Synthesis of the Bis-silylated Olefins
Organometallics, Vol. 25, No. 6, 2006 1475
Scheme 3
membered ring system. This unexpected assembling of a
macrocycle without precedent in rhenium-thioether chemistry
contrasts with the finding that in the case of platinum formation
of seven-membered chelate complexes such as 2a,b with this
dithioether ligand is observed (see above). When only 1 equiv
of the dithioether is added, the dinuclear complex fac-[{Re(µ-
Br)2(CO)3}2{µ-(PhSCH2)2Si2Me4}] (5) is isolated in 68% yield.
The framework of 4 is similar to the one reported for 1,1′-bis-
(mesitylthio)ferrocene bridging a Re2(CO)6Br2 dinuclear core.38
Addition of a second equivalent of 1 to a CH2Cl2 solution of 5
splits quantitatively within 1 h (NMR monitoring) the bromo-
bridges, forming the macrocyclic compound 4 (Scheme 3). 1H
NMR studies at variable temperature revealed also a dynamic
behavior for 4. Thus, at 298 K two singlets are observed for
the SiMe2 groups at δ 0.37 and 0.38, and raising the temperature
to 323 K results in convergence to a single resonance at δ 0.37
for the eight methyl groups.
Crystal Structures of 4 and 5. Suitable single crystals of 4
and 5 were grown from CH2Cl2/heptane. Complex 4 contains a
center of inversion (Figures 2a and 2b), and the symmetry of 5
results from the presence of a proper C2 axis perpendicular to
the Re2Br2 unit (Figure 5). In both cases, the rhenium centers
are in a slightly distorted octahedral environment with a facial
arrangement of the carbonyl groups. Note that the distortion is
more pronounced in compound 4, the cis angles being in the
range 80.73(6)-98.5(3)° [82.01(3)-94.73(19)° for complex 5].
The Re-S and Re-Br distances [4: Re-S(1) 2.530(2), Re-
S(2) 2.518(2), Re-Br 2.6212(13) Å; 5: Re-S 2.5056(13), Re-
Br 2.6479(8) and 2.6526(9) Å] lie in the range of what is
generally observed for these bonds.39-41 In particular the Re-S
bond distances are almost unaffected by the dithioether coor-
dination modes, e.g., chelating vs bridging. The Re2Br2 unit
remains almost planar in complex 5, in opposition to what is
observed in the more strained disulfide derivatives Re2Br2-
(CO)6S2R2 (R ) Me or Ph).36,37 The two rhenium atoms are at
a nonbonding distance of 3.996 Å. The flexible dithioether
adopts a conformation in which the two SiMe2 groups are
eclipsed, leading thus to a C2 symmetry. In compound 4, the
two rhenium centers are only linked by the adaptable dithioether
Figure 2. (a) Molecular structure of 4 in the solid state (Schakal
plot). Selected bond lengths (Å) and angles (deg): Re-Br 2.6212-
(13), Re-C(19) 1.894(10), Re-C(20) 1.901(11), Re-C(21) 1.911-
(10), Re-S(1) 2.530(2), Re-S(2) 2.518(2), S(1)-C(3) 1.807(9),
S(2)-C(12) 1.799(8), Si(1)-C(3) 1.908(10), Si(2)-C(12) 1.918-
(9) Si(1)-Si(2) 2.340(3), C(19)-Re-C(20) 88.8(4), C(19)-Re-
C(21) 87.5(3), C(20)-Re-C(21) 88.7(4), C(19)-Re-S(2) 174.6
(3), C(20)-Re-S(2) 86.1(2), C(21)-Re-S(2) 93.9(3), C(19)-Re-
S(1) 93.0(3), C(20)-Re-S(1) 172.6(3), C(21)-Re-S(1) 98.5(3),
C(19)-Re-Br 92.3(2), C(20)-Re-Br 92.0(3), C(21)-Re-Br
179.2(3), S(2)-Re-S(1) 91.89(7), S(2)-Re-Br 86.38(6), S(1)-
Re-Br 80.73(6), C(3)-S(1)-Re 107.5(3), C(3)-Si(1)-Si(2) 111.3-
(3). (b) View of the macrocyclic core structure of 4 (Schakal plot).
The phenyl groups have been omitted for clarity.
ligands. In this case, the two SiMe2 units are staggered and the
14-membered centrosymmetrical cycle thus generated exhibits
a transannular Re‚‚‚Re separation of 8.639 Å. The shortest
nonbonding distance between two opposite atoms in this
macrocycle is a S‚‚‚S contact of 5.235 Å.42
Synthesis of a Dinuclear Ruthenium Complex. The dimeric
compound [RuCl(µ-Cl)(CO)3]2 is known to be cleaved by
various nucleophiles such as PR3 or DMSO to give adducts of
the type [RuCl2(CO)3L].43,44 In the case of thioethers R2S,
formation of an adduct with 2,5-dihydrothiophene has been
reported.45 The functional ligand Ph2PCH2CH2SPh is coordi-
nated as both a monodentate and bidentate chelating ligand in
(42) For another recent example of a macrocycle incorporating a fac-
Re(CO)3 fragment see: Brasey, T.; Buryak, A.; Scopelliti, R.; Severin, K.
Eur. J. Inorg. Chem. 2004, 964.
(43) Benedetti, E.; Braca, G.; Sbrana, G.; Salvetti, F.; Grassi, B. J.
Organomet. Chem. 1972, 37, 361.
(44) Braunstein, P.; Knorr, M.; Strampfer, M.; Dusausoy, Y.; Bayeul,
D.; DeCian, A.; Fischer, J.; Zanello, P. J. Chem. Soc., Dalton Trans. 1994,
1533.
(41) Bushell, K.; Gialou, C.; Goh, C. H.; Long, N. J.; Martin, J.; White,
A. J. P.; Williams, C. K.; Williams, D. J.; Fontani, M.; Zanello, P. J.
Organomet. Chem. 2001, 637-639, 418.
(45) Sauer, N. N.; Angelici, R. J. Inorg. Chem. 1987, 26, 2160.

1476 Organometallics, Vol. 25, No. 6, 2006
Peindy et al.
Figure 3. Molecular structure of 5 in the solid state (Schakal plot).
Selected bond lengths (Å) and angles (deg): Re-Br 2.6479(8),
Re′-Br 2.6526(9), Re-C(1) 1.904(6), Re-C(2) 1.905(7), Re-C(3)
1.924(6), Re-S 2.5056(13), S-C(6) 1.820(5), Si-C(6) 1.904(5),
Si-Si 2.357(3), Re-Br-Re′ 97.87(3), C(1)-Re-C(2) 90.9(3),
C(1)-Re-C(3) 90.1(2), C(2)-Re-C(3) 90.0(2), C(1)-Re-S
94.06(15), C(2)-Re-S 88.55(15), C(3)-Re-S 175.61(17), C(1)-
Re-Br 94.73(19), C(2)-Re-Br 174.36(18), C(3)-Re-Br 89.64-
(15), S-Re-Br 91.45(3), C(1)-Re-Br′ 176.29(19), C(2)-Re-
Br′ 92.39(18), C(3)-Re-Br′ 91.65(16), S-Re-Br′ 84.29(3), Br-
Re-Br′ 82.01(3), C(6)-S-Re 114.68(16), C(6)-Si-Si′ 110.06(16).
Figure 5. Molecular structure of 7a in the solid state (Schakal
plot) and selected bond lengths (Å) and bond angles (deg): C(1)-
Si(1) 1.875(10), C(3)-S(1) 1.809(10), C(3)-Si(1) 1.895(8), C(4)-
S(1) 177.4(11), C(10)-C(11) 1.341(10), C(10)-Si(1) 1.912(8),
C(11)-C(12) 1.517(11), C(11)-Si(2) 1.886(9), C(18)-Si(2) 1.880-
(8), C(20)-S(2) 1.790(10), C(20)-Si(2) 1.919(7), C(21)-S(2)
1.763(11); C(4)-S(1)-C(3) 105.2(4), Si(1)-C(3)-S(1) 110.1(5),
C(11)-C(10)-Si(1) 135.1(7), C(12)-C(11)-Si(2) 116.9(5), C(11)-
Si(2)-C(20) 113.9(3), S(2)-C(20)-Si(2) 111.6(5), C(20)-S(2)-
C(21) 104.8(4), C(3)-Si(1)-C(10) 103.4(4), C(1)-Si(1)-C(10)
112.1(4), C(11)-Si(2)-C(18) 108.8(4), C(10)-C(11)-Si(2) 128.7-
(6).
Scheme 4
Figure 4. Molecular structure of 6 in the solid state (Schakal plot)-
and selected bond lengths (Å) and bond angles (deg): Ru-S
2.4349(6), Ru-Cl(1) 2.4018(7), Ru-Cl(2) 2.3938(6), S-C(4)
1.785(2), S-C(3) 1.805(2), Si-C(2) 1.863(3), Si-Si 2.3533(12),
Si-C(1) 1.871(3), Cl(1)-Ru-Cl(2) 91.45(2), C(10)-Ru-S 91.71-
(7), C(12)-Ru-S 173.41(8), Cl(2)-Ru-S 91.26(2), Cl(1)-Ru-S
86.32(2), C(3)-S-Ru 108.16(8), C(4)-S-Ru 109.75(7), C(2)-
Si-C(1) 109.77(14), C(2)-Si-Si 110.3(10), C(1)-Si-Si 113.51-
(10).
an inversion center. The separation between the two metal
centers amounts to 11.031 Å. Each ruthenium moiety has two
cis-arranged chloro ligands [Cl(1)-Ru-Cl(2) 91.45(2)°] and a
facial arrangement of the three carbonyl ligands. The SPh
function of the disilane ligand occupies the sixth position of
the octahedron, the two halide atoms being cis relative to the
Ru-S bond [2.4349(6) Å]. A comparable Ru-S bond length
[2.416(2) Å] has been established for trans-(Cl,Cl′)-[RuCl2-
(ptdmp)2], chelated by the phosphine-thioether ligand Me2PCH2-
CH2SPh.47 The fact that the disilane is now part of an linear
array without ring strain has no effect on the Si-Si bond length,
since it is almost identical with that found for the chelate
complex 2a [2.3533(12) vs 2.357(4) Å].
Catalytic Bis-silylation of Terminal Aromatic Acetylenes.
We have also attempted to prepare Pd-dithioether complexes
analogous to 2, which are ligated by 1. However, on treatment
of [PdCl2(PhCN)2] with a slight excess of 1 in dichloromethane
at ambient temperature, progressive darkening and precipitation
of large amounts of colloidal Pd was noticed. Since several
examples of stable Pd-dithioether complexes are known (see
above),28,48,49 this reduction to elemental Pd may be explained
by a competing oxidative addition of the Si-Si bond leading
to a labile silylated Pd(IV) species. This intermediate may then
decompose via reductive elimination of chlorosilanes. Note that
[RuCl2(CO)L2].46 We reacted 1 with 1 equiv of [RuCl(µ-Cl)-
(CO)3]2 in CCl4 solution at ambient temperature and obtained
the chain complex fac-[(OC)3Cl2Ru{µ-(PhSCH2)2Si2Me4)}RuCl2-
(CO)3] (6), in which the two metal fragments are linked by the
thioether functions (Scheme 4). IR monitoring shows that the
three ν(CO) vibrations of the starting material at 2139, 2081,
and 2075 cm-1 are replaced within 15 min by three bathochro-
mic shifted vibrations at 2132, 2074, and 2048 cm-1, indicating
a facial carbonyl arrangement. The NMR spectrum of yellowish
6 is quite simple and consists of a sharp singlet at δ -0.04 due
to four identical SiMe groups and a broad singlet at δ 3.09
attributed to the SCH2Si groups, which sharpens upon heating
to 318 K. The high symmetry of the dinuclear array is also
maintained in the solid state, as shown by an X-ray diffraction
study (see below).
Crystal Structure of 6. Figure 4 shows two octahedral
ruthenium(II) centers that are linked by the disilane via its
thioether substituents, the midpoint of the Si-Si bond being
(47) Taguchi, N.; Kashiwabara, K.; Nakajima, K.; Kawaguchi, H.;
Tatsumi, K. J. Organomet. Chem. 1999, 587, 290.
(46) Sanger, A. R.; Day, R. W. Inorg. Chim. Acta 1982, 62, 99.

Synthesis of the Bis-silylated Olefins
Organometallics, Vol. 25, No. 6, 2006 1477
Scheme 5
metals such as Ru, Re, and Pt, but reduces Pd(II). Due to its
flexibility, this ligand system can form seven-membered che-
lates, may assemble dinuclear complexes as bridging ligand,
and even permits the construction of macrocyclic ring systems.
Apart from this application in coordination chemistry, a promis-
ing potential for bis-silylation reaction also exists. Thus, in the
presence of aromatic terminal acetylenes and a Pd catalyst, the
Si-Si bond of 1 is cleaved, forming the bis-silylated olefin
Z-(PhSCH2)Me2SiC(H)dC(Ar)SiMe2(CH2SPh), 7. We are cur-
rently investigating the scope of the catalytic bis-silylation of
other unsaturated organic substrates and are trying to trap
reaction intermediates of this Pd-mediated reaction. Preliminary
studies indicate that 1 is furthermore a useful precursor for the
construction of cyclic trisilapentanes, which themselves are
prone to insert acetylenes (catalytically mediated by Pd(PPh3)4),
forming cyclic organosilicon compounds.52
recently the existence of silylated Pd(IV) complexes has been
confirmed by an X-ray diffraction study.50
Experimental Section
After exploring the propensity of 1 to act as a dithioether
ligand in coordination chemistry, we set out to study the
possibility of a metal-mediated activation of the Si-Si bond.
In light of the above-mentioned reduction of [PdCl2(PhCN)2]
in the presence of 1, it seemed promising to probe the
bis-silylation of phenylactylene and p-tolylacetylene using Pd-
(OAc)2/CNR as catalyst according to Scheme 5. Upon heating
a toluene solution of 1 containing an excess of Ar-CtC-H
and 5 mol % of the catalyst for 20 h, the mixture rapidly turned
red. After workup, the bis-silylated olefins Z-(PhSCH2)Me2SiC-
(H)dC(Ar)SiMe2(CH2SPh) (7a Ar ) Ph; 7b Ar ) p-Tol) were
isolated in the form of reddish crystals in the case of 7a or as
a brownish oil in the case of 7b in 71-81% yield. Bis-silylation
can even be performed across both triple bonds of 1,4-
diethynylbenzene to afford the redidsh compound 7c. Compari-
son of the spectroscopic data with those of 7a,b indicates also
a mutual syn-arrangement of the SiCH2SPh substituents of this
diolefin. We also probed the catalytic activity of Pd(PPh3)4
toward 1 and phenylacetylene in an NMR tube experiment.
NMR monitoring in C6D6 at 45 °C revealed that in the presence
of 10 mol % of this Pd(0) catalyst almost quantitative formation
of 7a took place. In contrast, no catalytic activity was observed
employing 2a or [RuCl(µ-Cl)(CO)3]2 in hot toluene.
Consistent with the proton NMR data, the syn-arrangement
of the two SiCH2SPh substituents of 7a has been confirmed by
an X-ray diffraction study (Figure 5). The bond distance of
1.341(10) Å between C(10) and C(11) is in the usual range for
olefinic double bonds; despite their bulkiness, the two silyl
substituents are almost coplanar, the dihedral angle Si(1)-
C(10)-C(11)-Si(2) being 3.05°. The bond lengths C(10)-Si-
(1) and C(11)-Si(2) [1.875(10) and 1.886(9) Å] parallel those
reported for the cyclic compound 5,6-carboranylene-1,1,4,4-
tetraethyl-2-phenyl-1,4-disilacyclohexene-2-ene [1.859(3) vs
1.873(3) Å], resulting from the reaction of 3,4-carboranylene-
1,1,2,2-tetraethyl-1,2-disilacyclobutene-3-ene with phenylacety-
lene.51
General Procedures. All reactions were performed in Schlenk-
tube flasks under purified nitrogen. Solvents were dried and distilled
under nitrogen before use, toluene and hexane over sodium, and
dichloromethane from P4O10. IR spectra have been recorded on a
Nicolet Nexus 470 spectrometer. Elemental C and H analyses were
1
performed on a Leco CHN 900 elemental analyzer. The H and
29Si{1H} NMR spectra were recorded at 300.13 and 39.76 MHz,
respectively, on a Bruker Avance 300 and a Bruker ACP 200
instrument. 195Pt chemical shifts were measured on a Bruker ACP
200 instrument (42.95 MHz) and externally referenced to K2PtCl4
in water with downfield chemical shifts reported as positive. NMR
spectra were recorded in pure CDCl3, unless otherwise stated. The
reactions were generally monitored by IR spectroscopy in the ν-
(CO) region.
Preparation of (PhSCH2)Me2SiSiMe2(CH2SPh) (1). To a
cooled suspension of 62 mmol of (phenylthiomethyl)lithium in 100
mL of diethyl ether, prepared from thioanisole and n-BuLi in diethyl
ether, was added at -50 °C a solution of dichlorotetramethylsilane
(5.20 g, 28 mmol) in 20 mL of hexane. The reaction mixture was
allowed to warm to room temperature, stirred for 12 h, and then
filtered. The solvent was evaporated in vacuo, and the residue was
purified by Kugelrohr distillation. Recrystallization of the oily
product from EtOH afforded 1 as a colorless solid (7.80 g, 78%
yield). Mp ) 54 °C. Anal. Calcd for C18H26Si2S2 (362.7): C, 59.61;
H, 7.22. Found: C, 59.0; H, 7.30. 1H NMR: δ 0.24 (s, 12H, SiCH3,
2
2JH,Si ) 6.5 Hz), 2.30 (s, 4H, SiCH2S, JH,Si ) 6.1 Hz), 7.0-7.34
(m, 10H, SC6H5). 13C{1H} NMR: δ -3.7 (4C, SiCH3), 17.2 (2C,
SiCH2S), 124.8 (2C, C-4 of SC6H5), 126.2 (4C, C-2/C-6 of SC6H5),
128.7 (4C, C-3/C-5 of SC6H5), 140.2 (2C, C-1 of SC6H5). 29Si-
{1H} NMR: δ -16.7.
Preparation of [PtCl2{(PhSCH2)2Si2Me4}] (2a). To a solution
of [PtCl2(PhCN)2] (472 mg, 1 mmol) in 10 mL of dichloromethane
was added 1 (370 mg, 1.1 mmol). The solution was stirred at 303
K for 24 h. The solvent then was removed under reduced pressure
and the residue rinsed with hexane. Recrystallization from dichlo-
romethane/hexane gave yellow crystals, which were filtered off and
dried under vacuum (534 mg, 85% yield). Anal. Calcd for C18H26-
Cl2PtS2Si2 (628.69): C, 34.39; H, 4.17. Found: C, 34.04; H, 4.11.
1H NMR (298 K): δ 0.41 (s, SiCH3), 0.54 (s, SiCH3), 2.28 (d, 2H,
Conclusion and Perspectives
2
3
2
We have shown that dithioether ligand 1 incorporating a
disilane unit forms stable complexes with various transition
HA, JHA,HB ) 11.8, JPt,HB ) 52 Hz), 3.36 (d, 2H, HB, JHA,HB
)
11.8 Hz). 195Pt{1H} NMR (323 K): δ -1846 (s, Pt).
Preparation of [PtI2{(PhSCH2)2Si2Me4}] (2b). To a solution
of 2a (315 mg, 0.5 mmol) in a 50:50 mixture of 12 mL of
dichloromethane/acetone was added a 10-fold excess of NaI. The
(48) Sanger, A. R.; Weiner-Fedorak, J. E. Inorg. Chim. Acta 1980, 42,
101.
(49) Murray, S. G.; Leavson, W.; Tuttlebee, H. E. Inorg. Chim. Acta
1981, 51, 185.
(50) Shimada, S.; Tanaka, M.; Shiro, M. Angew. Chem. 1996, 108, 1970.
(51) Song, K. H.; Jung, I.; Lee, S. S.; Park, K.-M.; Ishikawa, M.; Kang,
S. O.; Ko, J. Organometallics 2001, 20, 5537.
(52) Strohmann, C.; Ulbrich, O. In Organosilicon Chemistry IV: From
Molecules to Materials; Auner, N., Weis, J., Eds.; Wiley-VCH: Weinheim,
2000; pp 220-225.

Table 1. Crystal Data, Data Collection, and Structure Refinement
2a
2b
4
5
6
7
formula
fw
C18H26Cl2PtS2Si2
628.68
C19H28Cl2I2PtS2 Si2
896.50
C42H52Br2O6Re2S4Si4
712.83
C24H26Br2O6Re2S2Si2
1062.97
C25H28Cl6O6Ru2S2Si2
480.82
C26H32S2Si2
464.82
T (K)
173(2)
173(2)
173(2)
173(2)
193(2)
173(2)
cryst size (mm)
cryst syst
space group
a (Å)
b (Å)
c (Å)
0.30 × 0.20 × 0.20
0.30 × 0.20 × 0.20
monoclinic
P21/c
12.815(4)
11.1543(14)
19.862(4)
90
101.93(3)
90
2777.6(11)
4
0.30 × 0.20 × 0.10
0.30 × 0.30 × 0.10
monoclinic
C2/c
12.631(3)
18.693(4)
13.998(3)
90
100.09(3)
90
3253.8(11)
4
0.30 × 0.30 × 0.20
0.40 × 0.20 × 0.20
orthorhombic
Pca21
25.243(4)
6.464(2)
31.369(6)
90
90
90
5119.0(2)
8
1.206
triclinic
triclinic
triclinic
P1h
P1h
P1h
7.472(2)
9.403(2)
17.115(5)
98.43(3)
91.64(4)
104.07(3)
1151.3(5)
2
10.282(2)
10.615(2)
12.989(3)
109.11(3)
94.25(3)
8.1419(8)
8.9171(9)
13.2822(13)
101.2800(10)
90.773(2)
100.8300(10)
927.58(16)
2
R (deg)
â (deg)
γ (deg)
V (Å3)
Z
96.90(3)
1320.0(5)
1
1.793
6.385
F
calc (g‚cm-3
)
1.814
6.612
612
2.144
7.710
1680
2.170
10.126
1992
1.721
1.459
478
µ (mm-1
F(000)
)
0.313
1984
692
θ range, deg
2.26 to 26.00
-9 e h e 9,
-11 e k e 11,
-21 e l e 21
13 259
2.44 to 27.00
-16 e h e 16,
-14 e k e 14,
-25 e l e 23
25 065
2.45 to 26.00
-12 e h e 11,
-13 e k e 13,
-16 e l e 16
12 551
2.28 to 27.00
-16 e h e 16,
-23 e k e 21,
-17 e l e 17
12 393
2.55 to 25.00
-9 e h e 9,
-10 e k e 10,
-15 e l e 15
17 764
2.07 to 25.00
-30 e h e 28,
-5 e k e 7,
-36 e l e 31
13 649
index ranges
no. of collected reflns
no. of indep reflns
no. of data/restraints/
params
4243
4243/0/270
6019
6019/0/257
4835
4835/0/275
3324
3324/0/174
3248
3248/0/201
8206
8206/1/549
largest diff peak and
4.310 and -4.990
1.952 (near Pt and I)
and -3.196
3.978 and -3.317
1.679 and -2.286
0.887 and -0.790
0.464 and -0.323
hole, e Å-3
absolute structure factor
final R indices [I > 2σ(I)]
0.07(17)
R1 ) 0.0570,
wR2 ) 0.1521
R1 ) 0.0589,
wR2 ) 0.1539
1.054
R1 ) 0.0421,
wR2 ) 0.1057
R1 ) 0.0447,
wR2 ) 0.1080
1.031
R1 ) 0.0530,
wR2 ) 0.1246
R1 ) 0.0640,
wR2 ) 0.1309
1.011
R1 ) 0.0377,
wR2 ) 0.0909
R1 ) 0.0412,
wR2 ) 0.0929
1.058
R1 ) 0.0222,
wR2 ) 0.0569
R1 ) 0.0226,
wR2 ) 0.0573
1.047
R1 ) 0.0617,
wR2 ) 0.1143
R1 ) 0.1274,
wR2 ) 0.1291
1.011
R indices (all data)
GOF on F2

Synthesis of the Bis-silylated Olefins
Organometallics, Vol. 25, No. 6, 2006 1479
1
suspension was then stirred for 24 h. The solvent was then removed
under reduced pressure and the residue extracted with CH2Cl2. After
concentration of the extract, layering with hexane gave orange-red
crystals solvated by one molecule of CH2Cl2, which was lost after
prolonged drying in vacuo (265 mg, 79% yield). Anal. Calcd for
C18H26I2PtS2Si2 (810.88): C, 26.64; H, 3.23. Found: C, 26.32; H,
3.02. 1H NMR (298 K): δ 0.51 (s, br SiCH3), 2.32 (v br, unresolved,
HA), 3.53 (v br, unresolved, HB), 6.95-8.02 (m, phenyl).
Preparation of fac-[{ReBr(CO)3}2{µ-(PhSCH2)2Si2Me4}2] (4).
[{Re(µ-Br)(CO)3THF]2 (100 mg, 0.118 mmol) was dissolved in
10 mL of dichloromethane, and 2 equiv of 1 (86 mg, 0.236 mmol)
was added to the solution. The reaction mixture was stirred at room
temperature for 5 h and then concentrated under reduced pressure.
Addition of hexane and cooling gave pale yellow crystals, which
were filtered off and dried under vacuum (121 mg, 72% yield).
Anal. Calcd for C42H52Br2O6Re2S4Si4 (1425.66): C, 33.70; H, 3.68.
Found: C, 33.43; H, 3.83. IR (CH2Cl2) ν(CO): 2034s, 1942s, 1909s
cm-1. 1H NMR: δ 0.38 (s, 3H, SiCH3), 0.37 (s, 3H, SiCH3), 2.66
(d, 2H, 2JHA-HB ) 12 Hz), 3.71 (d, 2H, 2JHA-HB ) 12 Hz), 7.28-
7.66 (m, 10H, C6H5).
67.72; H, 7.16. Found: C, 67.49; H, 7.32. H NMR: δ 0.36 (s,
6H, SiCH3), 0.43 (s, 6H, SiCH3), 2.28 (s, 2H, SiCH2S), 2.35 (s,
3H, C6H4CH3), 2.37 (s, 2H, SiCH2S), 6.59 (s, 1H, dCH), 7.01-
7.30 (m, 14H, C6H5). 29Si{1H} NMR: δ -6.97 (s, 1Si), -10.05
(s, 1Si).
Preparation of (7c). This derivative was prepared as described
for 7a by heating a mixture of 1 (0.492 g, 1.36 mmol) and 1,4-
diethynylbenzene (0.126 g, 1.03 mmol) in the presence of the
catalyst (0.452 g, 84% yield). Anal. Calcd for C46H58S4Si4
(851.55): C, 64.88; H, 6.87. Found: C, 65.27; H, 7.11. 1H NMR:
δ 0.59 (s, 12H, SiCH3), 0.67 (s, 12H, SiCH3), 2.49 (s, 4H, SiCH2S),
2.61 (s, 4H, SiCH2S), 6.84 (s, 2H, dCH), 6.27-7.25 (m, 24 H,
C6H5). 13C{1H} NMR: δ -0.02 (4C, SiCH3), 0.04 (4C, SiCH3),
19.13 (2C, SiCH2S), 19.45 (2C, SiCH2S), 125.42-129.37 (1C,
phenyl), 140.52 (2C, SC6H5), 140.68 (2C, SC6H5), 147.85 (2C, d
CH), 148.09 (2C, phenyl), 164.18 (2C, dC-C6H5). 29Si{1H}
NMR: δ -6.68 (s, 1Si), -9.69 (s, 1Si).
Crystal Structure Determinations. Data of 2a, 2b, 4, 5, and 7
were collected on a Stoe IPDS diffractometer (Stoe & Cie GmbH)
using graphite-monochromated Mo KR radiation (λ ) 0.71069 Å).
The intensities were determined and corrected by the program
INTEGRATE in IPDS (Stoe & Cie, 1999). An empirical absorption
correction was employed using the FACEIT-program in IPDS (Stoe
& Cie, 1999). Data of 6 were collected on a Bruker APEX-CCD
(D8 three-circle goniometer) (Bruker AXS) using graphite-mono-
chromated Mo KR radiation (λ ) 0.71069 Å). The intensities were
determined and corrected by the programs Smart version 5.622
(Bruker AXS, 2001) and SaintPlus version 6.02 (Bruker AXS,
1999). An empirical absorption correction was employed using
Sadabs version 2.01 (Bruker AXS, 1999).
The structures were solved applying direct and Fourier methods,
using SHELXS-90 and SHELXL-97. For each structure the non-
hydrogen atoms were refined anisotropically. All of the H atoms
were placed in geometrically calculated positions, and each was
assigned a fixed isotropic displacement parameter based on a riding
model. The phenyl group on S(1) of 2a is disordered, and the
corresponding carbon atoms were refined on split positions.
Refinement of the structures was carried out by full-matrix least-
squares methods based on Fo2 using SHELXL-97. All calculations
were performed using the WinGX crystallographic software pack-
age. Crystal data, data collection parameters, and details of the
structure refinement are given in Table 1. ORTEP diagrams for
2a, 2b, 4, 5, 6, and 7 are included in the Supporting Information.
Crystallographic data (excluding structure factors) for the
structural analyses have been deposited with the Cambridge
Crystallographic Data Centre, CCDC Nos. 247286 for 2a, 247290
for 2b, 247289 for 4, 247288 for 5, 247287 for 6, and 247291 for
7. Copies of this information may be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge CB2 1EZ, U.K.
(fax +44-1223-336033; e-mail deposit@ccdc.cam.ac.uk; web http://
www.ccdc.cam.ac.uk).
Preparation of fac-[{Re(µ-Br)(CO)3}2-{µ-(PhSCH2)2Si2Me4}]
(5). Compound 5 was obtained in an analogous manner by reaction
of [{Re(µ-Br)(CO)3THF]2 (100 mg, 0.118 mmol) with 1 equiv of
1 (43 mg, 0.118 mmol) (85 mg, 68% yield). Anal. Calcd for C24H26-
Br2O6Re2S2Si2 (1062.97): C, 27.12; H, 2.47. Found: C, 26.87; H,
2.54. IR (CH2Cl2) (νCO): 2023s, 1928s, 1905s cm-1. 1H NMR: δ
-0.03 (s, 3H, SiCH3), -0.11 (s, 3H, SiCH3), 2.86 (d, 2H, 2JHA-HB
2
) 15 Hz), 3.26 (d, 2H, JHA-HB ) 15 Hz), 7.28-7.75 (m, 10H,
C6H5).
Preparation of fac-[(OC)3Cl2Ru{µ-(PhSCH2)2Si2Me4)}RuCl2-
(CO)3]2 (6). To a solution of [Ru(µ-Cl)(CO)3]2 (51 mg, 0.1 mmol)
in dry CCl4 (7 mL) was added 1a (0.043 g, 0.12 mmol). The mixture
was stirred at room temperature for 0.5 h and then the solvent
removed in vacuo. Yellowish single crystals were grown from CH2-
Cl2/hexane (0.058 g, 67% yield). Anal. Calcd for C24H26Cl4O6-
Ru2O6S2Si2: C, 32.95; H, 3.00. Found: C, 32.80; H, 2.88. IR (CCl4)
1
ν(CO): 2132 (s), 2074 (s), 2048 (m) cm-1. H NMR δ -0.04 (s,
12H, SiCH3), 3.09 (s, 4H, SCH2), 7.30-7.93 (m, 10H, SC6H5).
Preparation of Z-(PhSCH2)Me2SiC(H)dC(Ph)SiMe2(CH2SPh)
(7a). To a toluene solution (10 mL) containing 1 (0.492 g, 1.36
mmol), phenylacetylene (0.210 g, 2.06 mmol), and palladium
acetate (0.006 g, 0.028 mmol) was added 1,1,3,3 tetramethylbutyl
isocyanide (0.048 g, 0.42 mmol). The yellow mixture quickly turned
red after heating to 80 °C. Agitation was continued for 20 h, then
all volatiles were removed under reduced pressure. Extraction of
the oily residue with hexane and storing in a freezer at 5 °C gave
an analytically pure sample (0.448 g, 71% yield). Anal. Calcd for
C26H32S2Si2 (464.85): C, 67.18; H, 6.94. Found: C, 67.49; H, 7.02.
2
1H NMR: δ 0.33 (s, 6H, SiCH3, JH,Si ) 6.6 Hz), 0.39 (s, 6H,
SiCH3, 2JH,Si ) 6.6 Hz), 2.29 (s, 2H, SiCH2S), 2.39 (s, 2H, SiCH2S),
2
6.62 (s, 1H, dCH, JH,Si ) 16.7 Hz), 6.74-7.84 (m, 15H, C6H5).
13C{1H} NMR: δ 0.00 (2C, SiCH3), 0.02 (2C, SiCH3), 19.11 (1C,
SiCH2S), 19.46 (1C, SiCH2S), 125.21-129.75 (1C, phenyl), 140.53
(1C, SC6H5), 140.68 (1C, SC6H5), 148.07 (1C, dCH), 150.2 (1C,
phenyl), 164.47 (1C, dC-C6H5). 29Si{1H} NMR: δ -6.62 (s, 1Si),
-9.65 (s, 1Si).
Acknowledgment. We are grateful to the Deutschen Fors-
chungsgemeinschaft (DFG), the Fonds der Chemischen Industrie
(FCI), and the French Ministe`re de la Recherche et Technologie
for financial support.
Preparation of Z-(PhSCH2)Me2SiC(H)dC(p-Tol)SiMe2-
(CH2SPh) (7b). A toluene solution (2 mL) containing 1 (0.246 g,
0.64 mmol), p-tolylacetylene (0.120 g, 1.03 mmol), palladium
acetate (0.003 g, 0.014 mmol), and 1,1,3,3-tetramethylbutyl iso-
cyanide (0.029 g, 0.21 mmol) was heated under reflux for 7 h. The
solution was stood at room temperature, and then all volatiles were
removed under reduced pressure. The oily residue was dissolved
in pentane, filtered, and kept in a freezer at -25 °C. A brownish-
red solid precipitated, which melted again at ambient temperature
(0.248 g, 81% yield). Anal. Calcd for C27H34S2Si2 (478.86): C,
Supporting Information Available: Tables of X-ray structural
data, including data collection parameters, positional and thermal
parameters, bond distances and angles, and ORTEP plots for 2a,
2b, 4, 5, 6, and 7. UV-vis spectra of 1 and 2a and the 195Pt{1H}
NMR spectrum of 2a at variable temperature are also depicted.
This material is available free of charge via the Internet at
http://pubs.acs.org.
OM0489812