J. Am. Chem. Soc. 1997, 119, 3167-3168
3167
silicones.11 We report here the reaction of 1 with the bis(silane)
compounds, 1,2-bis(dimethylsilyl)benzene and 1,1,3,3-tetra-
methyldisiloxane, which leads to the first two examples of a
transition metal bis(silane) complex, where the two H-Si bonds
are η2-coordinated to the metal.
Synthesis and Characterization of Chelating
Bis(silane) Complexes
[RuH2{(η2-HSiMe2)2X}(PCy3)2] (X ) C6H4, O)
Containing Two Ru-(η2-Si-H) Bonds
Addition of (Me2SiH)2(C6H4) or (Me2SiH)2O to 1 suspended
in pentane leads to an immediate dissolution and reprecipitation
of a white powder, isolated and characterized as [RuH2{(η2-
HSiMe2)2X}(PCy3)2] (X ) (C6H4), (2); X ) O, (3)) in ca. 90%
yield. These complexes result from the substitution of the two
dihydrogen ligands of 1 by the bis(silane) (see eq 1). 2 and 3
Fabien Delpech, Sylviane Sabo-Etienne,*
Bruno Chaudret, and Jean-Claude Daran
Laboratoire de Chimie de Coordination
CNRS, UPR 8241, 205, route de Narbonne
31077 Toulouse Cedex France
ReceiVed NoVember 13, 1996
The η2-coordination of σ bonds to transition metals is an
intense area of research in coordination chemistry. Furthermore,
reactivity studies of the resulting complexes have intensified
over the past few years.1 However, complexes accommodating
more than one σ bond are rare: a few bis-agostic compounds
are known,2 and to date only two examples of thermally stable
bis(dihydrogen) complexes have been isolated, RuH2(H2)2-
(PCy3)2 (1) and Tp*RuH(H2)2.3 Whereas several transition
have been characterized by elemental analysis and by multi-
nuclear NMR and IR spectroscopies, and the structure of 2 has
1
been determined by X-ray crystallography.12,13 The H NMR
spectrum of 2 shows at 296 K in the hydride region a triplet at
δ -7.74 with JP-H ) 13 Hz and an AA′XX′ multiplet at δ
-12.03. These two signals observed in a 1:1 integration ratio
are respectively attributed to the two η2-bound Si-H protons
and the two hydrides. On warming, these two signals coalesce
at 355 K, leading to one broad signal at δ -9.9. This exchange
is characterized by a 64.5 kJ/mol barrier. T1 measurements on
the hydride resonances give a minimum value of 155 ms at
243 K and 250 MHz (no significant difference is observed for
the Si-H and hydride signals). This rules out the presence of
any (η2-H2) ligand in 2. The 31P{1H} spectrum shows at 296
K a single resonance at δ 51. The 29Si{31P} INEPT 1H spectrum
at 288 K shows a doublet at δ 4.8 with a JSi-H value of 63 Hz.
This value falls in the upper limit of the known range (20-100
Hz) of JSi-H values for (η2-Si-H) bonds.4,8,14-16 The IR
spectrum (Nujol mulls) displays one broad Ru-H stretch at 1969
metal complexes in which a simple silane, HSiR3, is η2
-
coordinated to the metal center have been reported,4 no
mononuclear complexes containing two M-(η2-Si-H) bonds
have been isolated so far. The mononuclear complex [IrH2-
(η2-HSiEt3)2(PPh3)2][SbF6] obtained by addition of 2 equiv of
Et3SiH to [IrH2(THF)2(PPh3)2][SbF6] was only characterized in
1
solution by H NMR.5 Some dinuclear (µ-silyl) complexes
{[Cp*Ru(µ-η2-HSiRR′)]2(µ-H)H}6,7 have been reported, and,
in the case of R ) Et, an X-ray structure determination proved
the existence of two Ru-(η2-H-Si) bonds.6 The synthesis and
the X-ray structure of the diiron complex [(CO)3Fe]2(µ-η2-
HSiPh2) have been recently reported, and the two agostic Fe-
H-Si bonds are characterized by NMR by a JH-Si of 23 Hz.8
cm-1 and an Ru-(η2-H-Si) band is observed at 1778 cm-1 17
.
We have previously shown that one dihydrogen ligand from
the bis(dihydrogen) complex RuH2(H2)2(PCy3)2 (1) is easily
substituted by HEPh3 (E ) Si, Ge) leading to the formation of
RuH2(H2)(HEPh3)(PCy3)2.9 Subsequently, we have demon-
strated that 1 is an efficient catalyst precursor for the selective
dehydrogenative silylation of ethylene into the vinylsilane
CH2dCHSiEt3.10 Thus, the extension of this system provides
a potential entry into a method for preparing vinylsiloxane
compounds which are of great interest for the manufacture of
This value together with the JSi-H value are in agreement with
the coordination of two (η2-Si-H) bonds. This is corroborated
by an X-ray diffraction study.13 The molecular structure of 2
(11) (a)Fleming, I.; Dunogues, J.; Smithers, R. H. Org. React. 1990, 37,
57. (b) Brown, S. S. D.; Heaton, S. N.; Moore M. H.; Perutz, R. N.; Wilson,
G. Organometallics 1996, 15, 1392 and references therein. (c) Brown, S.
S.; Kendrick; T. C.; McVie, J.; Thomas, D. R. In Comprehensive
Organometallic Chemistry II; Pergamon: 1995; Vol. 2, p 111. (d) Quirk,
J. M.; Kanner, B. U.S. Patent 4, 668, 812.
(12) Complex 2: (Me2SiH)2C6H4 (30 µL, 0.14 mmol) was added to a
solution of 1 (90 mg, 0.13 mmol) in pentane (6 mL). The mixture was
stirred for 10 min, and a white solid precipitated. It was collected by
filtration, washed twice with pentane (1.5 mL), and dried under vacuum
(yield 90%). Anal. Calcd for RuC46H86P2Si2: C, 64.37; H, 10.10. Found:
(1) (a) Crabtree, R. H. Angew. Chem., Int. Ed. Engl. 1993, 32, 789. (b)
Luo, X.-L.; Kubas, G. J.; Bryan, J. C.; Burns, C. J.; Unkefer, C. J. J. Am.
Chem. Soc. 1994, 116, 10312. (c) Kubas, G. J. Acc. Chem. Res. 1988, 21,
120. (d) Crabtree, R. H. Acc. Chem. Res. 1990, 23, 95. (e) Jessop, P. G.;
Morris, R. H. Coord. Chem. ReV. 1992, 121, 155. (f) Heinekey, D. M.;
Oldham, W. J., Jr. Chem. ReV. 1993, 93, 913. (g) Brookhart, M.; Green,
M. L. H.; Wong, L.-L. Prog. Inorg. Chem. 1988, 36, 1.
(2) (a) King, W. A.; Luo, X.-L.; Scott, B. L.; Kubas, G. J.; Zilm, K. W.
J. Am. Chem. Soc. 1996, 118, 6782. (b) Poole, A. D.; Williams, D. N.;
Kenwright, A. M.; Gibson, V. C.; Clegg, W.; Hockless, D. C. R.; O’Neil,
P. A. Organometallics 1993, 12, 2549 and references therein.
(3) (a) Arliguie, T.; Chaudret, B.; Morris, R. H.; Sella, A. Inorg. Chem.
1988, 27, 598. (b) Moreno, B.; Sabo-Etienne, S.; Chaudret, B.; Rodriguez,
A.; Jalon, F.; Trofimenko, S. J. Am. Chem. Soc. 1995, 117, 7441.
(4) Schubert, U. AdV. Organomet. Chem. 1990, 30, 151.
(5) Luo, X.-L.; Crabtree, R. H. J. Am. Chem. Soc. 1989, 111, 2527.
(6) Suzuki, H.; Takao, T.; Tanaka, M.; Moro-oka, Y. J. Chem. Soc.,
Chem. Commun. 1992, 476.
1
C, 64.43; H, 10.68. H NMR (400 MHz, C6D6, 296 K): δ -7.74 (t, 2H,
Ru-H-Si), -12.03 (AA′XX′, 2H, JH-P ) 25 and 46 Hz, Ru-H), 1.16 (s,
12H, Si-CH3), 1.23-2.28 (m, 66H, PCy3), 8.03 (m, 2H, C6H4, JH-H
)
7.4 and 1.2 Hz) 7.41(m, 2H, C6H4, JH-H ) 7.4 and 1.2 Hz).29Si{31P} INEPT
1H nonrefocalized (79.5 MHz, C6D6, 288 K) δ 4.8 (d, JSi-H ) 63 Hz). 29Si
INEPT 1H refocalized (79.5 MHz, C6D6) δ 4.8(t, JSi-P ) 8.3 Hz). 31P{1H}
NMR (161.99 MHz, C6D6): δ 50.97. IR (Nujol mulls): 1778 cm-1 (ν Ru-
H-Si); 1969 cm-1 (ν Ru-H). Complex 3: Anal. Calcd for RuC40H82OP2-
Si2: C, 60.12; H, 10.35. Found: C, 59.90; H, 10.38. 1H NMR (200 MHz,
C6D6, 296 K): δ -9.48 (br, 4H, Ru-H), 1.12 (s, 12H, Si-CH3), 1.1-
2.25 (m, 66H, PCy3). T1 min )144 ms (250 MHz, C7D8, 253 K).31P{1H}
NMR (81.015 MHz, C6D6): δ 49.94. 29Si{31P} NMR (79.5 MHz) δ -5.7-
(d, JSi-H ) 22 Hz). IR (Nujol mulls): 1699 cm-1 (ν Ru-H-Si); 2045 and
1969 cm-1 (ν Ru-H).
(13) Crystal data for 2: colorless crystal, monoclinic, I2/a, a ) 21.033-
(4) Å, b ) 19.714(2) Å, c ) 25.336(5) Å, â ) 90.01(2)°, Z ) 8, R )
0.0446, GOF ) 1.071.
(14) Luo, X.-L.; Kubas, G. J.; Burns, C. J.; Bryan, J. C.; Unkefer, C. J.
J. Am. Chem. Soc. 1995, 117, 1159.
(15) (a) Yin, J.; Klosin, J.; Abboud, K. A.; Jones, W. M. J. Am. Chem.
Soc. 1995, 117, 3298. (b) Lemke, F. R. J. Am. Chem. Soc. 1994, 116, 11183.
(16) Schubert, U.; Gilges, H. Organometallics 1996, 15, 2373.
(17) Takao, T.; Suzuki, H.; Tanaka, M. Organometallics 1994, 13, 2554.
(7) Campion, B. K.; Heyn, R. H.; Tilley, T. D. Organometallics 1992,
11, 3918.
(8) Simons, R. S.; Tessier, C. A. Organometallics 1996, 15, 2604.
(9) Sabo-Etienne, S.; Hernandez, M., Chung, G.; Chaudret, B.; Castel,
A. New J. Chem. 1994, 18, 175.
(10) Christ, M. L.; Sabo-Etienne, S.; Chaudret, B. Organometallics 1995,
14, 1082.
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