Facile Synthesis and Structures of η6-Arene Bis(silyl) Complexes of Ruthenium(II): (η6-arene)Ru(PPh 3)(SiX3)2

Article abstract of DOI:10.1021/om034009w

The reaction of RuCl₂(PPh₃)₃ with HSiX₃ in benzene produced (η⁶-benzene)Ru(PPh ₃)(SiX₃)₂ (SiX₃ = SiCl₃ (1), SiMeCl₂ (2)) as white to light yellow solids in high yields (>80%). A mixture of (η?⁶-benzene)Ru(PPh ₃)(SiMe₂Cl)₂ (3), (η ⁶-benzene)Ru(PPh₃)(SiMe₂Cl)(SiMeCl ₂) (4), and 2, due to silicon substituent redistribution, was obtained from the reaction of RuCl₂(PPh₃)₃ with HSiMe₂Cl in benzene. (η⁶-benzene)Ru(PPh ₃)(SiMe₃)₂ (5) was prepared by the methylation of 1, 2, or the 3/4 mixture with AlMe₃. The related complexes (η⁶-arene)Ru(PPh₃)-(SiMeCl₂)₂ (arene = toluene (6), o-xylene (7), m-xylene (8), p-xylene (9), mesitylene (10), anisole (11)) were obtained from the reaction of RuCl₂(PPh ₃)₃ with HSiMeCl₂ in the corresponding arene solvent at elevated temperature. Complexes 1, 2, and 5 were structurally characterized by single-crystal X-ray diffraction and exhibit a characteristic three-legged piano-stool geometry. The Ru-Si distances, in these complexes, ranged from 2.322 to 2.438 A; the Ru-Si distance increased as the number of methyl groups on silicon increased.

Full text of DOI:10.1021/om034009w

4928
Organometallics 2003, 22, 4928-4932
F a cile Syn th esis a n d Str u ctu r es of η6-Ar en e Bis(silyl)
Com p lexes of Ru th en iu m (II): (η6-a r en e)Ru (P P h 3)(SiX3)2
J ames Burgio,† Nicholas M. Yardy,† J effrey L. Petersen,‡ and
Frederick R. Lemke*,†
Department of Chemistry & Biochemistry, Ohio University, Athens, Ohio 45701, and
Department of Chemistry, West Virginia University, Morgantown, West Virginia 26506
Received J une 26, 2003
The reaction of RuCl2(PPh3)3 with HSiX3 in benzene produced (η6-benzene)Ru(PPh3)(SiX3)2
(SiX3 ) SiCl3 (1), SiMeCl2 (2)) as white to light yellow solids in high yields (>80%). A mixture
of (η6-benzene)Ru(PPh3)(SiMe2Cl)2 (3), (η6-benzene)Ru(PPh3)(SiMe2Cl)(SiMeCl2) (4), and 2,
due to silicon substituent redistribution, was obtained from the reaction of RuCl2(PPh3)3
with HSiMe2Cl in benzene. (η6-benzene)Ru(PPh3)(SiMe3)2 (5) was prepared by the methy-
lation of 1, 2, or the 3/4 mixture with AlMe3. The related complexes (η6-arene)Ru(PPh3)-
(SiMeCl2)2 (arene ) toluene (6), o-xylene (7), m-xylene (8), p-xylene (9), mesitylene (10),
anisole (11)) were obtained from the reaction of RuCl2(PPh3)3 with HSiMeCl2 in the
corresponding arene solvent at elevated temperature. Complexes 1, 2, and 5 were structurally
characterized by single-crystal X-ray diffraction and exhibit a characteristic three-legged
“piano-stool” geometry. The Ru-Si distances, in these complexes, ranged from 2.322 to 2.438
Å; the Ru-Si distance increased as the number of methyl groups on silicon increased.
In tr od u ction
During our ongoing investigations into the chemistry
of ruthenium(II) half-sandwich complexes,1-6,14,15 we
discovered a facile synthetic route for the formation of
(η6-arene)RuL(SiX3)2san underrepresented class of three-
legged “piano-stool” ruthenium(II) complexes. This pa-
per describes the synthesis and characterization of (η6-
arene)Ru(PPh3)(SiMeCl2)2 (arene ) benzene, toluene,
o-xylene, m-xylene, p-xylene, mesitylene, anisole) com-
plexes. The structural dependence of the benzene series,
(η6-benzene)Ru(PPh3)(SiX3)2 (SiX3 ) SiCl3, SiMeCl2,
SiMe3), on silyl substituents is described. Also reported
is the substituent redistribution reaction of HSiMe2Cl
that was observed in the preparation of (η6-benzene)-
Ru(PPh3)(SiMe2Cl)2.
Three-legged “piano-stool” ruthenium silyl complexes
containing the cyclopentadienyl ligand, Cp(PR3)2RuSi-
1-6
X3
and Cp*(PR3)2RuSiX3,7-11 have been used as
model systems to explore the nature and reactivity of
the ruthenium-silicon bond. However, there are only
a few examples of (η6-arene)RuL(SiX3)2 complexes with
the same three-legged “piano-stool” geometry. (η6-
C6H6-nRn)Ru(CO)(SiCl3)2 (R ) Me, n ) 1-4, 6; R ) But,
n ) 1, 2; R ) Cl, n ) 1) were prepared by heating cis-
or trans-Ru(CO)4(SiCl3)2 and the appropriate arene.12
(η6-C6H5Me)Ru(CO)(xantsil) (xantsil ) (9,9-dimethyl-
xanthene-4,5-diyl)bis(dimethysilyl)) was prepared from
cis-Ru(CO)4(xantsil) in refluxing toluene; (η6-C6H6)Ru-
(CO)(xantsil) was obtained by dissolving (η6-C6H5Me)-
Ru(CO)(xantsil) in benzene.13
Resu lts a n d Discu ssion
Syn th esis of (η6-a r en e)Ru (P P h 3)(SiX3)2. The reac-
tion of RuCl2(PPh3)3 with hydrosilanes (HSiCl3 and
HSiMeCl2) and benzene in the presence of 1-octene at
elevated temperatures provided a facile synthetic route
to (η6-C6H6)Ru(PPh3)(SiX3)2 (SiX3 ) SiCl3 (1), SiMeCl2
(2)) complexes (eq 1). Complexes 1 and 2 were isolated
† Ohio University.
‡ West Virginia University (crystal structure determinations).
(1) Lemke, F. R. J . Am. Chem. Soc. 1994, 116, 11183-11184.
(2) Lemke, F. R.; Brammer, L. Organometallics 1995, 14, 3980-
3987.
(3) Lemke, F. R.; Simons, R. S.; Youngs, W. J . Organometallics 1996,
15, 216-221.
(4) Lemke, F. R.; Chaitheerapapkul, C. Polyhedron 1996, 15, 2559-
2565.
(5) Lemke, F. R.; Galat, K. J .; Youngs, W. J . Organometallics 1999,
18, 1419-1429.
(6) Freeman, S. T. N.; Lofton, L. L.; Lemke, F. R. Organometallics
2002, 21, 4776-4784.
(7) Straus, D. A.; Zhang, C.; Quimbita, G. E.; Grumbine, S. D.; Heyn,
R. H.; Tilley, T. D.; Rheingold, A. L.; Geib, S. J . J . Am. Chem. Soc.
1990, 112, 2673-2681.
(8) Straus, D. A.; Tilley, T. D.; Rheingold, A. J .; Geib, S. J . J . Am.
Chem. Soc. 1987, 109, 5872-5873.
(9) Grumbine, S. K.; Tilley, T. D.; Arnold, F. P.; Rheingold, A. L. J .
Am. Chem. Soc. 1994, 116, 5495-5496.
(10) Grumbine, S. K.; Straus, D. A.; Tilley, T. D. Polyhedron 1995,
14, 127-148.
(13) Tobita, H.; Hasegawa, K.; Minglana, J . J . G.; Luh, L.-S.;
Okazaki, M.; Ogino, H. Organometallics 1999, 18, 2058-2060.
(14) Brammer, L.; Klooster, W. T.; Lemke, F. R. Organometallics
1996, 15, 1721-1727.
(15) Freeman, S. T. N.; Lemke, F. R.; Haar, C. M.; Nolan, S. P.;
Petersen, J . L. Organometallics 2000, 19, 4828-4833.
(11) Grumbine, S. K.; Mitchell, G. P.; Straus, D. A.; Tilley, T. D.
Organometallics 1998, 17, 5607-5619.
(12) Pomeroy, R. K.; Harrison, D. J . J . Chem. Soc., Chem. Commun.
1980, 661-663.
10.1021/om034009w CCC: $25.00 © 2003 American Chemical Society
Publication on Web 10/23/2003

η6-Arene Bis(silyl) Complexes of Ruthenium(II)
Organometallics, Vol. 22, No. 24, 2003 4929
Ta ble 1. Rela tive Con cen tr a tion s of 2, 3, a n d 4 a s
a F u n ction of Tim e in th e Rea ction of
Ru Cl2(P P h 3)3 w ith HSiMe2Cla
as orange and yellow solids, respectively, in high yields
(>90%). 1-Octene was not required for the formation of
1 and 2, although product yields and purity were
increased when 1-octene was present. GC analysis of
the mother liquor for the formation of 2 showed the
presence of octane, indicating that 1-octene was acting
as a hydrogen scavenger in this reaction. Also, no
hydrosilylation products of 1-octene were observed,
consistent with the reported observation that the RuCl-
(PPh3)3/HSiMeCl2 system did not hydrosilylate sty-
rene.16 The reaction of HSiEt3 with RuCl2(PPh3)3 in
benzene did not produce (η6-C6H6)Ru(PPh3)(SiEt3)2 but
instead formed RuHCl(PPh3)3; the formation of RuHCl-
(PPh3)3 from the reaction of HSiEt3 with RuCl2(PPh3)3
has been reported.17-19
time
2
3
4
2 h
22 h
2 d
trace
3.4
17
7
3
1
1
1
1
20
15
22
6 d
a
Reaction conditions: RuCl2(PPh3)3 (65 mg, 0.068 mmol),
HSiMe2Cl (2 mL), 1-octene (1 mL), benzene (1.5 mL) heated to
65 °C.
reaction of RuCl2(PPh3)3 with HSiMe2Cl in benzene. The
conversion of 3 to 4 was very facile; 4 became the major
species in the reaction mixture in a matter of hours. On
the other hand, the conversion of 4 to 2 was very slow;
2 was only a minor species even after 3 was converted
to 4. Also in this reaction, no evidence for the formation
of (η6-C6H6)Ru(PPh3)(SiMeCl2)(SiCl3) or 1 was observed.
The reaction of RuCl2(PPh3)3 with HSiMe2Cl in benzene
at room temperature, studied as a function of time,
proceeded in manner similar to that for the 65 °C
reaction, except that more time was required for the
formation and conversion of 3 and 4.
The reaction of RuCl2(PPh3)3 with HSiMe2Cl in the
presence of benzene and 1-octene was more complicated
(eq 2); redistribution of the substituents in HSiMe2Cl
occurred, producing a mixture of (η6-C6H6)Ru(PPh3)(Si-
Me2Cl)2 (3), (η6-C6H6)Ru(PPh3)(SiMe2Cl)(SiMeCl2) (4),
and 2. Attempts to separate this mixture into its
Recently, we have reported that Si-Cl bonds in
ruthenium silyl complexes containing the Cp(PR3)2Ru
(PR3 ) PMe3, PMe2Ph, PMePh2) moiety could readily
be methylated by AlMe3.5,6 Thus, in a similar manner,
the trimethylsilyl derivative (η6-C6H6)Ru(PPh3)(SiMe3)2
(5) was prepared in good yield as a light yellow solid by
the reaction of 1, 2, or the 2/3/4 mixture with AlMe3 in
toluene (eq 3).
individual components by fractional recrystallization
were unsuccessful, due to the similar solubility proper-
ties of complexes 2-4. The composition of this mixture
was dependent on reaction time and temperature. When
the reaction described in eq 2 was carried out at room
temperature for 3 days, the isolated solid was a mixture
of 3 and 4 in a 3:1 ratio with only a trace of 2. On the
other hand, if the reaction temperature was increased
to 65 °C, 4 was the major species in the isolated solid
(a mixture of 4, 3, and 2 in a 12:7:1 ratio).
The redistribution of substituents in organosilanes
with the aid of transition metals has been investigated
for some time.20 The substituent redistribution of HSiMe2-
Cl observed in eq 2 poses an interesting set of questions.
Does the redistribution of HSiMe2Cl precede the forma-
tion of the η6-benzene bis(silyl) complexes, or does
scrambling of the methyl groups occur after the η6-
benzene bis(silyl) complexes are formed? To address
these questions, the reaction of RuCl2(PPh3)3 with
HSiMe2Cl at 65 °C was monitored as a function of time.
The results of this study are reported in Table 1. The
results indicated that methyl group scrambling occurred
after the η6-benzene bis(silyl) complexes were formed.
Complex 3 was the initial species formed from the
The reaction in eq 1 was readily extended to other
arene systems. (η6-arene)Ru(PPh3)(SiMeCl2)2 (arene )
toluene (6), o-xylene (7), m-xylene (8), p-xylene (9),
mesitylene (10), anisole (11)) were obtained in good
yields (65-85%) from the reaction of RuCl2(PPh3)3 with
HSiMeCl2 in the corresponding arene (eq 4).
The simplicity and mild conditions employed in the
preparation of complexes 1-11 are unusual compared
to the methods used to prepare related (η6-arene)RuL-
(SiX3)2 complexes. The preparation of (η6-C6H5Me)Ru-
(CO)(xantsil) was a two-step process, employing tem-
peratures up to 120 °C; Ru3(CO)12 was reacted with
xantsilH2 to form Ru(CO)4(xantsil), which was then
reacted with toluene to form (η6-C6H5Me)Ru(CO)-
(xantsil).13 (η6-C6H6-nRn)Ru(CO)(SiCl3)2 (R ) Me, n )
1-4, 6; R ) But, n ) 1-2; R ) Cl, n ) 1) were prepared
(16) Yardy, N. M.; Lemke, F. R. Main Group Chem. 2000, 3, 143-
147.
(17) Kono, H.; Wakao, N.; Ito, K.; Nagai, Y. J . Organomet. Chem.
1977, 132, 53-67.
(18) Svoboda, P.; Rericha, R.; Hetflejs, J . Collect. Czech. Chem.
Commun. 1974, 39, 1324-1329.
(19) Haszeldine, R. N.; Malkin, L. S.; Parish, R. V. J . Organomet.
Chem. 1979, 182, 323-332.
(20) Curtis, M. D.; Epstein, P. S. Adv. Organomet. Chem. 1981, 19,
213-255.

4930 Organometallics, Vol. 22, No. 24, 2003
Burgio et al.
Ta ble 2. Selected In ter a tom ic Dista n ces (Å) a n d
An gles (d eg) for (η6-C6H6)Ru (P P h 3)(SiX3)2 (SiX3 )
SiCl3 (1), SiMeCl2 (2), SiMe3 (5))
SiCl3
SiMeCl2
SiMe3
Ru-Si(1)
Ru-Si(2)
Ru-P
2.3273(8)
2.344(2)
2.4377(11)
2.4352(10)
2.3048(10)
1.803
2.3218(8)
2.3486(7)
1.825
2.354(2)
2.3413(13)
1.818
2.116(23)
1.905(21)
1.853(6)
Ru-Ar(c)a
Si-Cl (av)b
Si-C (av)b
P-C (av)b
2.086(12)
1.903(10)
1.853(5)
1.843(6)
Ar(c)-Ru-Si(1)a 120.9
Ar(c)-Ru-Si(2)a 121.3
122.4
120.8
127.9
121.0
120.4
130.1
Ar(c)-Ru-Pa
Ru-Si(1)-Xc
127.7
124.48(4) (Cl(1)) 129.2(2) (C(7)) 124.03(13) (C(7))
113.71(4) (Cl(2)) 112.03(8) (Cl(1)) 112.8(2) (C(8))
114.59(5) (Cl(3)) 110.66(8) (Cl(2)) 113.45(14) (C(9))
114.53(4) (Cl(4)) 118.3(2) (C(8)) 125.23(13) (C(10))
112.26(4) (Cl(5)) 122.33(8) (Cl(3)) 112.8(2) (C(11))
125.69(5) (Cl(6)) 112.52(7) (Cl(4)) 113.14(14) (C(12))
F igu r e 1. 1H NMR chemical shifts of the C6H6 and SiMe
groups and the 31P NMR chemical shift of PPh3 versus the
total number of methyl groups in the ruthenium silyl
complexes (η6-C6H6)Ru(PPh3)(SiX3)2 (1-5). Average values
Ru-Si(2)-Xc
1
Cl-Si-Cl (av)b 100.1(11)
Cl-Si-C (av)b
99.1(18)
100.5(12)
were used for the SiMe H NMR chemical shifts of 3 and
4.
C-Si-C (av)b
100.9(15)
a
b
by heating cis- or trans-Ru(CO)4(SiCl3)2 with the ap-
propriate arene in excess of 120 °C.12 The facile syn-
thesis of (η6-arene)Ru(PPh3)(SiX3)2 complexes reported
herein will make this class of silyl complexes more
readily available for further investigation.
Ar(c) corresponds to the centroid of the benzene ring. Num-
bers in parentheses represent the 95% confidence limit for average
distances and angles. c X represents either a chlorine or carbon
bonded to silicon.
NMR Spectr a of (η6-ar en e)Ru (P P h 3)(SiX3)2. Multi-
nuclear NMR characterizations of 1-11 were consistent
with the formulation and molecular connectivity of these
η6-arene bis(silyl) ruthenium complexes. In 1H NMR
spectra, the η6-arene CH and Me resonances were
observed in the 5-6 ppm and 1.5-2.5 regions, respec-
tively, while the SiMe resonances were observed as
singlets in the 0-0.6 ppm region. The SiMe2Cl methyl
groups in 3 and 4 were diastereotopic. Both the arene
CH and SiMe resonances exhibited an inverse linear
relationship with the total number of silyl methyl
groups in complexes 1-5 (Figure 1). The silyl group
silicons in 1-11 were observed as doublets (J SiP ) 25-
32 Hz) around 72-79 ppm in the 29Si{1H} DEPT NMR
spectra; the only exception was the SiMe3 group of 5,
which was observed as a doublet (J SiP ) 26 Hz) at 10.46
ppm. The PPh3 groups were observed in the 31P{1H}
NMR spectra as singlets in the 35-55 ppm region and
exhibited a linear relationship with the total number
of silyl methyl groups in 1-5 (Figure 1).
F igu r e 2. Perspective view of the molecular structure of
(η6-C6H6)Ru(PPh3)(SiCl3)2 (1) with atom labels provided for
all unique non-hydrogen atoms. The thermal ellipsoids are
scaled to enclose 30% probability.
Str u ctu r es of (η6-C6H6)Ru (P P h 3)(SiX3)2. The crys-
tal structures of (η6-C6H6)Ru(PPh3)(SiX3)2 (SiX3 ) SiCl3
(1), SiMeCl2 (2), SiMe3 (5)) were determined by X-ray
diffraction at 295 K. Pertinent interatomic distances and
angles for 1, 2, and 5 are given in Table 2. The molecular
structures of 1, 2, and 5 (Figures 2-4, respectively)
confirm the formulation and connectivity of the (η6-
benzene)ruthenium bis(silyl) complexes described above.
Complexes 1, 2, and 5 adopt a three-legged “piano-stool”
geometry around ruthenium, with “legs” composed of
one PPh3 and two silyl groups. The Ru-Si distances of
2.32-2.44 Å are consistent with a single bond and fall
within the range (2.27-2.51 Å) observed for d6 ruthe-
nium silyl complexes.3,5,7,10,21,22 Also, in these complexes,
the average Si-Cl distance (2.10 ( 0.01 Å) was slightly
(CO)(SiCl3)2 (2.07 ( 0.01 Å)23 but shorter than the Si-
Cl distances (2.11-2.17, 2.13 ( 0.01 Å average) observed
in related d6 Cp(PR3)2Ru(SiX3) complexes.4,5,24
Complexes 1, 2, and 5 have a staggered conformation
about the Ru-Si bond with the benzene and either a
chloride or methyl group in an anti relationship (average
benzene centroid-Ru-Si-X dihedral angle 166.3 (
2.8°). The silyl group has a distorted-tetrahedral geom-
etry with an average X-Si-X (X ) Cl, C) angle of
100.3 ( 0.7° and an average Ru-Si-X angle of
117.3 ( 2.4°. The anti Ru-Si-X angles (125.2 ( 1.8°
average) are significantly larger than the non-anti Ru-
Si-X angles (113.4 ( 0.9°). In related three-legged
“piano-stool” Cp ruthenium silyl complexes, the Ru-
Si-X angle for substituents anti to a Cp group have also
been observed to be g10° larger than Ru-Si-X angles
longer than the Si-Cl distances in (η6-p-But C6H4)Ru-
2
(21) Tilley, T. D. In The Silicon-Heteroatom Bond; Patai, S., Rap-
poport, Z., Eds.; Wiley: New York, 1991; pp 245-307.
(22) Tilley, T. D. In The Silicon-Heteroatom Bond; Patai, S., Rap-
poport, Z., Eds.; Wiley: New York, 1991; pp 309-364.
(23) Einstein, F. W. B.; J ones, T. Inorg. Chem. 1982, 21, 987-990.
(24) Freeman, S. T. N. Thesis, Department of Chemistry & Bio-
chemistry, Ohio University, Athens, OH, 2002; p 194.

η6-Arene Bis(silyl) Complexes of Ruthenium(II)
Organometallics, Vol. 22, No. 24, 2003 4931
of SiCl3 was deduced to be about half the π-acceptor
ability of CO, while the SiMe3 group exhibited little to
no π-acidity.26 The increase in the Ru-Si distances of
1, 2, and 5 were accompanied by decreases in the Ru-P
(2.349 Å (SiCl3) to 2.305 Å (SiMe3)) and Ru-Ar(c) (1.825
Å (SiCl3) to 1.803 Å (SiMe3)) distances. These inter-
atomic distance changes were consistent with a decrease
in the π-acidity of the silyl group being compensated
by an increased π-interaction with PPh3 and benzene.
Exp er im en ta l Section
Gen er a l P r oced u r es. All manipulations were carried out
under an argon atmosphere using either standard vacuum line
or glovebox techniques.27 1H NMR (250, 400, and 500 MHz)
were obtained using Bruker AC-250, Varian VXR 400S, and
Varian Inova 500 spectrometers, respectively, and were ref-
erenced to the residual proton peak of the solvent. 31P NMR
(101.26 MHz) spectra were obtained using a Bruker AC-250
spectrometer and externally referenced to 85% H3PO4. 29Si-
{1H} DEPT (79.5 MHz) was recorded on a Varian VXR 400s
spectrometer and externally referenced to SiMe4.
F igu r e 3. Perspective view of the molecular structure of
(η6-C6H6)Ru(PPh3)(SiMeCl2)2 (2) with atom labels provided
for all unique non-hydrogen atoms. The thermal ellipsoids
are scaled to enclose 30% probability.
Ma ter ia ls. RuCl2(PPh3)3 was prepared by the published
method28 or used as received from Pressure Chemical (Lot
#026588001). Hexanes, pentane, benzene, and toluene (Fisher)
were deolefinated with concentrated H2SO4, distilled from
potassium/benzophenone, and stored over [Cp2TiCl2]2ZnCl2.29
Xylenes (o-, m-, and p-), mesitylene, and anisole were purified
according to published procedures.30 Benzene-d6 (Cambridge
Isotopes) and diethyl ether (Spectrum Chemical) were de-
gassed and stored over [Cp2TiCl2]2ZnCl2.29 Dichloromethane
was distilled from and stored over CaH2. Dichloromethane-d2
(Cambridge Isotopes) was stored over CaH2. Chlorohydrosi-
lanes (HSiCl3, HSiMeCl2, HSiMe2Cl; Gelest) were dried and
stored over CaH2. Triethylsilane (Gelest) was distilled under
reduced pressure from molecular sieves and stored under
argon. All solvents and volatile reagents were degassed prior
to use by three standard freeze/pump/thaw degassing cycles.
Syn th esis of (η6-C6H6)Ru (P P h 3)(SiR3)2 (SiR3 ) SiCl3 (1),
SiMeCl2 (2)). In a typical experiment, a 25 mL reaction vessel
was charged with RuCl2(PPh3)3 (250 mg, 2.6 mmol), benzene
(5 mL), and 1-octene (4 mL) in the glovebox. HSiCl2Me (3 mL,
∼23.4 mmol) was added by vacuum transfer. The reaction
vessel was sealed and placed in a 65 °C oil bath for 14 h. The
reaction volume was reduced by 50%, and hexanes (2 mL) were
added by vacuum transfer. The precipitate was collected,
washed with hexanes, and dried in vacuo to afford 2 (150 mg,
86%) as a light yellow solid. GC analysis of the mother liquor
shows the presence of 1-octene, octane, and triphenylphos-
phine. Complex 1 was obtained as an orange solid in good
yields (75-85%). Qualitatively, HSiMeCl2 was more reactive
toward RuCl2(PPh3)3 than HSiCl3, possibly due to the de-
creased solubility of SiCl3-containing species. 1: 1H NMR (CD2-
Cl2) δ 7.45, 7.64 (m, 15 H, PPh3), 5.97 (s, 6H, C6H6); 13C{1H}
NMR (CD2Cl2) δ 134.90, 131.20, 128.21 (s, Ph), 101.5 (d, J PC
) 32.1 Hz, C6H6); 29Si{1H} DEPT NMR (CD2Cl2) insufficient
solubility of 1 to obtain spectrum; 31P{1H} NMR (CD2Cl2) δ
37.87 (s). Anal. Calcd for C24H21Cl6PRuSi2: C, 40.58; H, 2.98.
Found: C, 40.40; H, 3.21. 2: 1H NMR (CD2Cl2) δ 7.01, 7.22
(m, 15H PPh3), 5.82 (s, 6H, C6H6), 0.52 (s, 6H, SiCl2Me); 13C-
{1H} NMR (CD2Cl2) δ 136.50, 134.96, 130.80, 128.05 (m, Ph),
100.30 (d, J PC ) 25.2 Hz, C6H6), 18.70 (s, SiCl2Me); 29Si{1H}
F igu r e 4. Perspective view of the molecular structure of
(η6-C6H6)Ru(PPh3)(SiMe3)2 (5) with atom labels provided
for all unique non-hydrogen atoms. The thermal ellipsoids
are scaled to enclose 30% probability.
for the other substituents on silicon: Cp(PMe3)2RuSiCl3
(Ru-Si-Cl(anti) ) 125.6° vs Ru-Si-Cl ) 115.9° (av)),5
Cp(PMe3)2RuSiCl2Cp* (Ru-Si-Cl(anti) ) 119.9° vs
Ru-Si-Cl ) 109.2°),3 Cp*(PMe3)2RuSiPh2H (Ru-Si-
H(anti) ) 112.9° vs Ru-Si-Ph ) 98.8° (av)),7 and Cp*-
(PMe3)2RuSiPh2OTf (Ru-Si-OTf(anti) ) 118.2° vs Ru-
Si-Ph ) 96.9° (av)).10
Within this series of η6-benzene bis(silyl) ruthenium
complexes, the Ru-Si distances increased from 2.325
Å (av, SiCl3) to 2.436 Å (av, SiMe3) as the electronega-
tive chlorides were replaced with methyl groups. A
similar trend was observed in the series Os(SiR3)Cl(CO)-
(PPh3)2 (R ) F, Cl, OH, Me), where the Os-Si distances
increased from 2.273(6) Å (R ) Cl) to 2.374(2) Å (R )
Me).25 These changes in Ru-Si and Os-Si distances can
be attributed to a decrease in the π-acceptor ability of
the silyl group as chlorides are replaced with methyl
groups. On the basis of photoelectron studies of CpFe-
(CO)2SiR3 (SiR3 ) SiCl3, SiMe3), the π-acceptor ability
(26) Lichtenberger, D. L.; Rai-Chaundhuri, A. J . Am. Chem. Soc.
1991, 113, 2923-2930.
(27) Shriver, D. F.; Drezdzon, M. A. The Manipulation of Air-
Sensitive Compounds, 2nd ed.; Wiley-Interscience: New York, 1986.
(28) Komiya, S., Ed. Synthesis of Organometallic Compounds:
Practical Guide; Wiley: New York, 1997.
A
(29) Sekutowski, D. G.; Stucky, G. D. Inorg. Chem. 1975, 14, 2192-
(25) Hu¨bler, K.; Hunt, P. A.; Maddock, S. M.; Rickard, C. E. F.;
Roper, W. R.; Salter, D. M.; Schwerdtfeger, P.; Wright, L. J . Organo-
metallics 1997, 16, 5076-5083.
2199.
(30) Perrin, D. D.; Armarego, W. L. F. Purification of Laboratory
Chemicals; Pergamon Press: New York, 1988.

4932 Organometallics, Vol. 22, No. 24, 2003
Burgio et al.
DEPT NMR (CD2Cl2) δ 77.26 (d, J SiP ) 29.9 Hz); 31P{1H} NMR
(CD2Cl2) δ 41.13 (s). Anal. Calcd for C26H27Cl4PRuSi2: C, 46.64;
H, 4.06. Found: C, 46.49; H, 3.93.
1.90 (s, 3H, Me), 0.48 (s, 6H, SiCl2Me); 13C{1H} NMR (CD2-
Cl2) δ 136.24 (d, J PC ) 45.0 Hz, PPh3 ipso-C), 135.32 (d, J PC
)
10.7 Hz, PPh3 o-C), 130.82 (s, PPh3 p-C), 128.04 (d, J PC ) 10.0
Hz, PPh3 m-C), 118.93 (s, CMe), 101.99, 99.87, 97.66 (s, toluene
CH), 19.49 (s, CMe), 18.90 (s, SiCl2Me); 29Si{1H} DEPT NMR
(CD2Cl2) δ 77.86 (d, J SiP ) 29.9 Hz); 31P{1H} NMR (CD2Cl2) δ
44.27 (s). Anal. Calcd for C29H27Cl4PRuSi2: C, 47.44; H, 4.28.
Found: C, 46.17; H, 4.27. 7: 1H NMR (CD2Cl2) δ 7.42, 7.70
(m, 15H, PPh3), 5.97 (m, 2H, CH), 5.75 (m, 2H, CH), 1.73 (s,
6H, Me), 0.45 (s, 6H, SiCl2Me); 13C{1H} NMR (CD2Cl2) δ 135.52
(d, J PC ) 10.7 Hz, PPh3 o-C), 130.74 (d, J PC ) 1.5 Hz, PPh3
p-C), 127.93 (d, J PC ) 9.8 Hz, PPh3 m-C), 117.30 (s, CMe),
103.21 (s, xylene CH), 97.60 (s, xylene CH), 18.96 (s, CMe),
17.90 (s, SiCl2Me); 29Si{1H} DEPT NMR (CD2Cl2) δ 78.82 (d,
J SiP ) 29.3 Hz); 31P{1H} NMR (CD2Cl2) δ 45.66 (s). Anal. Calcd
for C28H31Cl4PRuSi2: C, 48.21; H, 4.48. Found: C, 47.93; H,
4.68. 8: 1H NMR (CD2Cl2) δ 7.43, 7.79 (m, 15H, PPh3), 6.07
(t, J HH ) 6.1 Hz, 1H, CH), 5.76 (d, J HH ) 6.1 Hz, 2H, CH),
4.94 (s, 1H, CH), 2.06 (s, 6H, Me), 0.44 (s, 6H, SiCl2Me); 13C-
{1H} NMR (CD2Cl2) δ 135.67 (d, J PC ) 10.8 Hz, PPh3 o-C),
130.83 (d, J PC ) 2.3 Hz, PPh3 p-C), 127.97 (d, J PC ) 9.9 Hz,
PPh3 m-C), 117.64 (s, CMe), 106.90 (s, xylene CH), 99.65 (d,
J PC ) 2.3 Hz, xylene CH), 97.52 (d, J PC ) 2.3 Hz, xylene CH),
19.68 (s, CMe), 19.08 (s, SiCl2Me); 29Si{1H} DEPT NMR (CD2-
Cl2) δ 77.87 (d, J SiP ) 30.0 Hz); 31P{1H} NMR (CD2Cl2) δ 46.37
Crystals of 1 suitable for X-ray diffraction were grown at
room temperature by the slow vapor diffusion of THF into an
acetonitrile solution of 1, which was covered by a layer of
hexanes. Crystals of 2 suitable for X-ray diffraction were grown
at room temperature by the vapor diffusion of Et2O into CH2-
Cl2 solutions of 2. Details concerning the crystallographic
analysis of 1 and 2 are given in the Supporting Information.
Syn th esis of (η6-C6H6)Ru (P P h 3)(SiMe2Cl)2 (3) a n d (η6-
C6H6)Ru (P P h 3)(SiMe2Cl)(SiMeCl2) (4). A mixture of com-
plexes 3, 4, and 2 was obtained from the reaction of RuCl2-
(PPh3)3 with HSiCl2Me in benzene. The composition of this
mixture was dependent on the reaction temperature. In a
typical experiment, a 25 mL reaction vessel was charged with
Ru(PPh3)3Cl2 (250 mg, 2.6 mmol), benzene (5 mL), and 1-octene
(4 mL) in the glovebox. HSiCl2Me (3 mL, ∼23.4 mmol) was
added by vacuum transfer. If this reaction mixture was stirred
at room temperature for 3 days, a yellow solution with an off-
white precipitate was obtained. Workup of this sample, as
described for 1 and 2, afforded 132 mg of an off-white solid,
which was determined by 1H NMR spectroscopy to be a
mixture of 3 and 4 in a 3:1 ratio with a trace of 2. On the
other hand, heating the RuCl2(PPh3)3/HSiMe2Cl reaction
mixture to 65 °C for 14 h followed by the usual workup
afforded an off-white solid in similar yields. The composition
of this solid was determined to be a mixture of 4, 3, and 2 in
a 12:7:1 ratio. 3: 1H NMR (CD2Cl2) δ 7.39, 7.67 (m, 15H, PPh3),
5.57 (s, 6H, C6H6), 0.53 (s, 6H, SiMe2Cl), 0.17 (s, 6H, SiMe2-
Cl); 29Si{1H} DEPT NMR (CD2Cl2) δ 72.31 (d, J SiP ) 23.2 Hz);
31P{1H} NMR (CD2Cl2) δ 46.99 (s). 4: 1H NMR (CD2Cl2) δ 7.39,
7.67 (m, 15H, PPh3), 5.70 (s, 6H, C6H6), 0.70 (s, 3H, SiMe),
0.32 (s, 3H, SiMe), 0.15 (s, 3H, SiMe); 29Si{1H} DEPT NMR
(CD2Cl2) δ 79.31 (d, J SiP ) 33.0 Hz), 73.27 (d, J SiP ) 26.9 Hz);
31P{1H} NMR (CD2Cl2) δ 44.67 (s).
(s). Anal. Calcd for
C28H31Cl4PRuSi2: C, 48.21; H, 4.48.
Found: C, 48.13; H, 4.37. 9: 1H NMR (CD2Cl2) δ 7.41, 7.74
(m, 15H, PPh3), 5.37 (s, 4H, CH), 2.37 (s, 6H, Me), 0.52 (s, 6H,
SiCl2Me); 13C{1H} NMR (CD2Cl2) δ 137.01 (d, J PC ) 45.8 Hz,
PPh3 ipso-C), 135.42 (d, J PC ) 10.7 Hz, PPh3 o-C), 130.65 (d,
J PC ) 2.3 Hz, PPh3 p-C), 127.92 (d, J PC ) 9.8 Hz, PPh3 m-C),
117.34 (s, CMe), 100.49 (d, J PC ) 3.0 Hz, xylene CH), 19.80 (s,
CMe), 19.76 (s, SiCl2Me); 29Si{1H} DEPT NMR (CD2Cl2) δ 78.67
(d, J SiP ) 29.3 Hz); 31P{1H} NMR (CD2Cl2) δ 44.61 (s). Anal.
Calcd for C28H31Cl4PRuSi2: C, 48.21; H, 4.48. Found: C, 48.31;
H, 4.52. 10: 1H NMR (CD2Cl2) δ 7.43, 7.84 (m, 15H, PPh3),
5.35 (s, 3H, CH), 2.23 (s, 9H, Me), 0.43 (s, 6H, SiCl2Me); 13C-
{1H} NMR (CD2Cl2) δ 135.82 (d, J PC ) 9.7 Hz, PPh3 o-C),
130.82 (s, PPh3 p-C), 127.84 (d, J PC ) 9.9 Hz, PPh3 m-C),
112.88 (s, CMe), 105.72 (d, J PC ) 1.5 Hz, mesitylene CH), 19.84
(s, CMe), 19.13 (s, SiCl2Me); 29Si{1H} DEPT NMR (CD2Cl2) δ
77.46 (d, J SiP ) 31.2 Hz); 31P{1H} NMR (CD2Cl2) δ 46.49 (s).
Anal. Calcd for C29H33Cl4PRuSi2: C, 48.95; H, 4.67. Found:
C, 48.84; H, 4.80. 11: 1H NMR (CD2Cl2) δ 7.73, 7.43 (m, 15H,
PPh3), 6.31 (t, J HH ) 6.1 Hz, 2H, CH), 5.37 (m, 3H, CH), 3.33
(s, 3H, OMe), 0.50 (s, 6H, SiCl2Me); 13C{1H} NMR (CD2Cl2) δ
135.38 (d, J PC ) 10.8 Hz, PPh3 o-C), 130.78 (d, J PC ) 2.2 Hz,
PPh3 p-C), 127.92 (d, J PC ) 9.8 Hz, PPh3 m-C), 114.22 (s, CMe),
103.41 (d, J PC ) 2.2 Hz, anisole CH), 89.10 (d, J PC ) 3.1 Hz,
anisole CH), 84.78 (s, anisole CH), 56.59 (s, OMe), 18.67 (s,
SiCl2Me); 29Si{1H} DEPT NMR (CD2Cl2) δ 78.91 (d, J SiP ) 28.7
Hz). Anal. Calcd for C27H29Cl4OPRuSi2: C, 46.36; H, 4.18.
Found: C, 46.27; H, 4.17.
Syn th esis of (η6-C6H6)Ru (P P h 3)(SiMe3)2 (5). Complex 5
was prepared by the reaction of AlMe3 with 1, 2, or the 2/3/4
mixture. In a typical experiment, a 25 mL Schlenk flask was
charged with 1 (50 mg, 0.07 mmol) and toluene (10 mL) to
form a yellow slurry. AlMe3 (0.25 mL, 0.5 mmol, 2.0 M in
toluene or hexanes) was added by syringe, and the reaction
mixture was stirred for 1 h at room temperature. The resulting
clear yellow solution was filtered through Celite and the
filtrate evaporated to dryness. The residue was slurried with
hexanes, filtered, and dried under vacuum to yield 5 (14 mg,
33%) as a yellow solid. Similar yields of 5 were obtained upon
the methylation of either 2 or the 2/3/4 mixture. 1H NMR (CD2-
Cl2): δ 7.2, 7.4 (m, 15H, PPh3), 5.21 (s, 6H, C6H6), 0.037 (s,
18H, SiMe3). 13C{1H} NMR (CD2Cl2): δ 134.40, 129.36, 127.51
(m, Ph), 92.18 (d, J PC ) 2.3 Hz, C6H6), 11.04 (s, SiMe3). 29Si-
{1H} DEPT NMR (CD2Cl2): δ 10.46 (d, J SiP ) 25.7 Hz). 31P-
{1H} NMR (CD2Cl2): δ 52.04 (s).
Crystals of 5 suitable for X-ray diffraction were grown at
room temperature by the vapor diffusion of Et2O into CH2Cl2
solutions of 5. Details concerning the crystallographic analysis
of 5 are given in the Supporting Information.
Ack n ow led gm en t . F.R.L. thanks the Research
Challenge and Condensed Matter and Surface Science
programs at Ohio University and Dow Corning Corp.
for financial support. J .B. thanks the Provost Under-
graduate Research Fund at Ohio University for financial
support. J .L.P. acknowledges the financial support
provided by the Chemical Instrumentation Program of
the National Science Foundation (Grant No. CHE-
9120098) to acquire a Siemens P4 X-ray diffractometer.
Syn th esis of (η6-a r en e)Ru (P P h 3)(SiMeCl2)2 (a r en e )
Tolu en e (6), o-Xylen e (7), m -Xylen e (8), p-Xylen e (9),
Mesitylen e (10), An isole (11)). In a typical experiment, a
25 mL reaction vessel was charged with RuCl2(PPh3)3 (115 mg,
1.2 mmol), toluene (3 mL), and 1-octene (4 mL) in the glovebox.
HSiCl2Me (1 mL, ∼7.8 mmol) was added by vacuum transfer.
The reaction vessel was sealed and placed in a 65 °C oil bath
for 14-24 h. The reaction volume was reduced by 50%, and
hexanes (2 mL) were added by vacuum transfer. The precipi-
tate was collected, washed with hexanes, and dried in vacuo
to afford 6 (58 mg, 71%) as a light yellow solid. Complexes
7-11 were also obtained as light yellow to orange solids in
good yields (65-85%). 6: 1H NMR (CD2Cl2) δ 7.43, 7.75 (m,
15H, PPh3), 5.97 (m, 3H, CH), 5.43 (d, J HH ) 5.9 Hz, 2H, CH),
Su p p or tin g In for m a tion Ava ila ble: Text describing the
collection of X-ray data and tables of crystal data, data
collection and refinement parameters, interatomic distances,
and interatomic angles for 1, 2 and 5. Full crystallographic data
as CIF files are also available for 1, 2, and 5. This material is
available free of charge via the Internet at http://pubs.acs.org.
OM034009W