Synthesis and reactivity of a dithiolate-bridged ruthenium-rhodium heterobimetallic dihydride complex

Article abstract of DOI:10.1021/om050871n

The new dithiolate-bridged Ru-Rh heterobimetallic dihydride complex [Cp*Rh(μ₂-1,2-S₂C₆H ₄)(μ₂H)RuH(PPh₃)₂] (2) has been prepared, and its reactions with CO and alkynes have been studied. Treatment of the rhodium 1,2-benzenedithiolate complex [Cp*Rh(1,2-S₂C ₆H₄)] (Cp* = η⁵-C₅Me ₅) with [RuHCl(PPh₃)₃] in THF produces the hydride- and dithiolate-bridged Ru-Rh heterobimetallic complex [Cp*Rh(μ₂-1,2-S₂C₆H ₄)(μ₂-H)RuCl(PPh₃)₂] (1), which was further converted to the dihydride complex [Cp*Rh(μ₂1,2- S₂C₆H₄)(μ₂-H)RuH(PPh ₃)₂] (2) upon treatment with KOH/i-PrOH. Complex 2 reacts with CO to give the dicarbonyl complex [Cp*Rh(μ₂-1,2-S ₂C₆H₄)Ru(CO)₂(PPh₃)] (3). Reaction of 2 with p-tolylacetylene (2 equiv) proceeds with hydrogenation of the alkyne and subsequent oxidative addition of the sp C-H bond to give the alkynyl hydride complex [Cp*Rh(μ₂-1,2-S₂C ₆H₄)(μ₂-H)Ru(C≡CTol-p)(PPh ₃)₂] (4a). The analogous alkynyl hydride complex [Cp*Rh(μ₂-1,2-S₂C₆H ₄)(μ₂-H)Ru(C≡CSiMe₃)(PPh ₃)₂] (4b) has also been prepared. Complex 4a reacts with excess p-tolylacetylene to produce the ruthenacyclopentadiene complex [Cp*Rh{μ₂-η²:η⁴-1,3-(p-Tol) ₂C₄H₂}Ru(S₂C₆H ₄)(PPh₃)] (5), whereas similar treatment of 4a with excess diphenylacetylene induces 1:2 coupling of the two different alkynes to form the η⁶-arene complex [Cp*Rh(μ₂-1,2-S ₂C₆H₄)Ru{η⁶-C₆Ph ₄H(p-MeC₆H₄)}] (6). Reaction of 4a with CO proceeds with dissociation of one of the Ru-S bonds and with retention of the alkynyl hydride structure to give the CO adduct [Cp*Rh(μ₂-1, 2-S₂C₆H₄)(μ₂-H)Ru(C≡CTol-p) (CO)(PPh₃)₂] (7). The structures of 1, 3, 4b, and 5-7 have been determined by X-ray crystallography.

Full text of DOI:10.1021/om050871n

982
Organometallics 2006, 25, 982-988
Synthesis and Reactivity of a Dithiolate-Bridged
Ruthenium-Rhodium Heterobimetallic Dihydride Complex
Shin Takemoto,† Daisuke Shimadzu,† Ken Kamikawa,† Hiroyuki Matsuzaka,*,†,‡ and
Ryoki Nomura§
Department of Chemistry, Graduate School of Science, Osaka Prefecture UniVersity, Sakai,
Osaka 599-8531, Japan, Coordination Chemistry Laboratories, Institute for Molecular Science, Myodaiji,
Okazaki 444-8787, Japan, and Osaka Institute of Technology, Omiya, Asahi-ku, Osaka 535-8585, Japan
ReceiVed October 7, 2005
The new dithiolate-bridged Ru-Rh heterobimetallic dihydride complex [Cp*Rh(µ2-1,2-S2C6H4)(µ2-
H)RuH(PPh3)2] (2) has been prepared, and its reactions with CO and alkynes have been studied. Treatment
of the rhodium 1,2-benzenedithiolate complex [Cp*Rh(1,2-S2C6H4)] (Cp* ) η5-C5Me5) with [RuHCl-
(PPh3)3] in THF produces the hydride- and dithiolate-bridged Ru-Rh heterobimetallic complex [Cp*Rh-
(µ2-1,2-S2C6H4)(µ2-H)RuCl(PPh3)2] (1), which was further converted to the dihydride complex [Cp*Rh(µ2-
1,2-S2C6H4)(µ2-H)RuH(PPh3)2] (2) upon treatment with KOH/i-PrOH. Complex 2 reacts with CO to give
the dicarbonyl complex [Cp*Rh(µ2-1,2-S2C6H4)Ru(CO)2(PPh3)] (3). Reaction of 2 with p-tolylacetylene
(2 equiv) proceeds with hydrogenation of the alkyne and subsequent oxidative addition of the sp C-H
bond to give the alkynyl hydride complex [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCTol-p)(PPh3)2] (4a).
The analogous alkynyl hydride complex [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCSiMe3)(PPh3)2] (4b) has
also been prepared. Complex 4a reacts with excess p-tolylacetylene to produce the ruthenacyclopentadiene
complex [Cp*Rh{µ2-η2:η4-1,3-(p-Tol)2C4H2}Ru(S2C6H4)(PPh3)] (5), whereas similar treatment of 4a with
excess diphenylacetylene induces 1:2 coupling of the two different alkynes to form the η6-arene complex
[Cp*Rh(µ2-1,2-S2C6H4)Ru{η6-C6Ph4H(p-MeC6H4)}] (6). Reaction of 4a with CO proceeds with dis-
sociation of one of the Ru-S bonds and with retention of the alkynyl hydride structure to give the CO
adduct [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCTol-p)(CO)(PPh3)2] (7). The structures of 1, 3, 4b, and
5-7 have been determined by X-ray crystallography.
sandwich metal 1,2-dithiolate (or dithiolene) derivatives [(η5-
Cp′)M(S-S)] (Cp′ ) cyclopentadienyl and substituted cyclo-
pentadienyls; M ) Co, Rh, Ir) have attracted much attention.17-24
Reflecting the coordinatively unsaturated nature of the metal
center, these compounds tend to give heteronuclear metal-metal
Introduction
There continues to be much interest in the chemistry of
heterodinuclear transition-metal complexes, in which two dif-
ferent metal atoms are close to each other and thus may behave
cooperatively.1,2 During the last two decades, there have been
considerable advances in the methods to synthesize such
compounds.3 In particular, complexes containing terminal
thiolate ligands have been recognized as useful building blocks
for higher nuclearity compounds.4-16 Among them, half-
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1998, 37, 6428-6434.
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Int. Ed. 1999, 38, 1098-1100.
(20) del Rio, I.; Terroba, R.; Cerrada, E.; Hursthouse, M. B.; Laguna,
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4231.
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Inorg. Chem. 2004, 43, 1197-1205.
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Nakamura, A. Organometallics 1997, 16, 1016-1025.
(24) Xi, R.; Abe, M.; Suzuki, T.; Nishioka, T.; Isobe, K. J. Organomet.
Chem. 1997, 549, 117-125.
* To whom correspondence should be addressed. E-mail: matuzaka@
c.s.osakafu-u.ac.jp.
† Osaka Prefecture University.
‡ Institute for Molecular Science.
§ Osaka Institute of Technology.
(1) Metal Clusters in Chemistry; Braunstein, P., Oro, L. A., Raithby, P.
R., Eds.; Wiley-VCH: Weinheim, Germany, 1999.
(2) Catalysis by Di- and Polynuclear Metal Cluster Complexes; Adams,
R. A., Cotton, F. A., Eds.; Wiley-VCH: New York, 1998.
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1995; Vol. 10, Chapter 1, pp 1-22.
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1217-1220.
(5) Shin, R. Y. C.; Teo, M. E.; Tan, G. K.; Koh, L. L.; Vittal, J. J.; Goh,
L. Y.; Murray, K. S.; Moubaraki, B.; Zhou, X.-Y. Organometallics 2005,
24, 4265-4273.
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10.1021/om050871n CCC: $33.50 © 2006 American Chemical Society
Publication on Web 01/19/2006

A Dithiolate-Bridged Ru-Rh Dihydride Complex
Organometallics, Vol. 25, No. 4, 2006 983
Scheme 1
bonded µ-dithiolate compounds upon interaction with Lewis
acidic metal fragments.19,21 As a part of our interest in the
chemistry of reactive dinuclear late-transition-metal com-
plexes,25-28 we have sought to utilize the 16-electron rhodium
1,2-benzenedithiolate complex [Cp*Rh(S2C6H4)]24 for the prepa-
ration of heterobimetallic complexes in which the dinuclear core
is electronically unsaturated or readily opens up vacant coor-
dination site(s). Herein we report the synthesis of the dithiolate-
bridged ruthenium-rhodium heterobimetallic dihydride complex
[Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)RuH(PPh3)2] (2), which is, to our
knowledge, the first example of a thiolate-bridged heterobime-
tallic dihydride complex. Complex 2 exhibits a chemistry
resulting from facile hydrogen loss, producing the lower-valent
carbonyl adduct [Cp*Rh(µ2-1,2-S2C6H4)Ru(CO)2(PPh3)] (3)
upon interaction with carbon monoxide and the alkynyl hydride
complexes [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCR)(PPh3)2]
(4a, R ) p-Tol; 4b, R ) SiMe3) via alkyne C-H bond
activation. The reactivity of 4a toward alkynes and CO is also
described.
Figure 1. Thermal ellipsoid plot (25% probability level) of
[Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)RuCl(PPh3)2] (1). Hydrogen atoms,
except for the bridging hydride, are omitted for clarity. Selected
bond lengths (Å): Rh(1)-Ru(1), 2.7586(7); Rh(1)-S(1), 2.3354-
(17); Rh(1)-S(2), 2.3540(17); Ru(1)-S(1), 2.4367(17); Ru(1)-
S(2), 2.4273(18); Ru(1)-Cl(1), 2.4272(14); Ru(1)-P(1), 2.3089-
(16); Ru(1)-P(2), 2.3289(17).
triphenylphosphine ligands on ruthenium. An ORTEP drawing
of 1 is depicted in Figure 1. The hydride ligand was located in
the final difference Fourier map. The molecule contains a triply
bridged heterodinuclear core with an intermetallic separation
of 2.7586(7) Å, a distance consistent with a Rh-H-Ru three-
center-two-electron bond.30 The rhodium center is coordinated
in a three-legged piano-stool geometry, while the ruthenium
center is in a distorted-octahedral geometry, in which the
terminal chloride ligand is trans to the bridging hydride.
Treatment of 1 with excess KOH in 2-propanol at 60 °C
afforded the dihydride complex [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)-
RuH(PPh3)2] (2) (Scheme 1), which was obtained as a mixture
of cis- and trans-dihydride isomers in an 8:2 molar ratio as
Results and Discussion
As outlined in Scheme 1, the hydride- and dithiolate-bridged
heterodinuclear framework was readily synthesized by treating
the rhodium dithiolate complex [Cp*Rh(S2C6H4)] with the
ruthenium hydride complex [RuHCl(PPh3)3] in THF at room
temperature. The synthetic strategy is related to that employed
for the synthesis of the chloro-bridged heterodinuclear com-
pound [Cp*Rh(µ2-Cl)3RuCl(PPh3)2].29 The product [Cp*Rh(µ2-
1,2-S2C6H4)(µ2-H)RuCl(PPh3)2] (1) was isolated in 84% yield
as deep blue plates and characterized by NMR spectroscopy,
1
judged by the H NMR spectrum. Complex 2 was isolated in
∼70% yield as an air-sensitive purple microcrystalline solid and
characterized by elemental analysis and NMR spectroscopy.
Each of the isomers exhibits a set of two distinct hydride
resonances in the 1H NMR spectrum: the cis isomer at δ -9.79
and -14.00 and the trans isomer at δ -8.23 and -8.53. The
31P{1H} NMR spectrum shows two mutually coupled doublets
2
(δ 68.8 and 64.5, JPP ) 11 Hz) attributable to the two
inequivalent phosphorus atoms in the cis isomer and a singlet
resonance at δ 70.3 for the trans isomer.
1
elemental analysis, and X-ray crystallography. The H NMR
spectrum is consistent with the bridging hydride formulation,
Di- and polyhydride complexes are frequent sources of lower
valent coordinatively unsaturated metal species by undergoing
H2 reductive elimination or transferring dihydrogen to unsatur-
ated substrates.31 Although the dihydride 2 is thermally stable
up to 110 °C in toluene, it reacts smoothly with 2 equiv of
carbon monoxide at room temperature to produce the dicarbonyl
showing a characteristic high-field resonance at δ -17.05 (dt,
2
1JRh-H ) 25.7 Hz, JP-H ) 12.8 Hz). The 31P{1H} NMR
spectrum indicates the existence of chemically equivalent
(25) Takemoto, S.; Oshio, S.; Shiromoto, T.; Matsuzaka, H. Organo-
metallics 2005, 24, 801-804.
(26) Takemoto, S.; Kobayashi, T.; Matsuzaka, H. J. Am. Chem. Soc.
2004, 126, 10802-10803.
(30) Iwasa, T.; Shimada, H.; Takami, A.; Matsuzaka, H.; Ishii, Y.; Hidai,
M. Inorg. Chem. 1999, 38, 2851-2859.
(27) Takemoto, S.; Oshio, S.; Kobayashi, T.; Matsuzaka, H.; Hoshi, M.;
Okimura, H.; Yamashita, M.; Miyasaka, H.; Ishii, T.; Yamashita, M.
Organometallics 2004, 23, 3587-3589.
(31) For example, see: (a) Suzuki, H.; Kakigano; T.; Tada, K.; Igarashi,
M.; Matsubara, K.; Inagaki, A.; Oshima, M.; Takao, T. Bull. Chem. Soc.
Jpn. 2005, 78, 67-87. (b) Krogh-Jespersen, K.; Czerw, M.; Summa, N.;
Renkema, K. B.; Achord, P. D.; Goldman, A. S. J. Am. Chem. Soc. 2002,
124, 11404-11416. (c) Janowicz, A. H.; Bergman, R. G. J. Am. Chem.
Soc. 1982, 104, 352-354.
(28) Takemoto, S.; Ogura, S.; Kamikawa, K.; Matsuzaka, H. Inorg. Chim.
Acta, in press.
(29) Quebatte, L.; Scopelliti, R.; Severin, K. Angew. Chem., Int. Ed. 2004,
43, 1520-1524.

984 Organometallics, Vol. 25, No. 4, 2006
Takemoto et al.
Scheme 2
Figure 2. Thermal ellipsoid plot (25% probability level) of
[Cp*Rh(µ2-1,2-S2C6H4)Ru(CO)2PPh3] (3). Hydrogen atoms are
omitted for clarity. Selected bond lengths (Å): Rh(1)-Ru(1),
2.6139(12); Rh(1)-S(1), 2.352(2); Rh(1)-S(2), 2.3401(17); Ru-
(1)-S(1), 2.4299(17); Ru(1)-S(2), 2.4285(18); Ru(1)-C(1), 1.852-
(7); Ru(1)-C(2), 1.858(7); Ru(1)-P(1), 2.364(2); C(1)-O(1),
1.161(7); C(2)-O(2), 1.143(7).
at δ -9.65 (ddd, cis) and -10.88 (dt, trans) assignable to the
bridging hydride. Treatment of 2 with (trimethylsilyl)acetylene
afforded the analogous alkynyl hydride complex [Cp*Rh(µ2-
1,2-S2C6H4)(µ2-H)Ru(CtCSiMe3)(PPh3)2] (4b), which was
isolated as a single cis isomer after recrystallization from
toluene-acetonitrile and has been structurally characterized.34
The structure of 4b is shown in Figure 3. The Ru(1)-C(1) and
C(1)-C(2) bond lengths (2.004(6) and 1.221(10) Å, respec-
tively) as well as Ru(1)-C(1)-C(2) bond angle (169.6(6)°) are
typical for Ru(II) terminal alkynyl complexes.35 The Ru(1)-
Rh(1) distance of 2.7708(7) Å is comparable to that of 1 and is
consistent with the Rh-H-Ru three-center-two-electron bond.
To gain insight into the mechanism of the above alkyne
activation, the dihydride complex 2 was treated with 2 equiv
complex [Cp*Rh(µ2-1,2-S2C6H4)Ru(PPh3)(CO)2] (3) (Scheme
2a), which was isolated in 80% yield and characterized by
spectroscopic, analytical, and crystallographic methods. Mo-
lecular hydrogen was detected by the 1H NMR spectrum of the
reaction mixture, although the amount of the evolved hydrogen
was not quantified. We believe coordination of CO induces
reductive elimination of H2 from the dinuclear core. The IR
spectrum of 3 shows two ν(CO) bands at 1985 and 1921 cm-1
,
which are comparable to those observed for the bis-thiolate-
bridged dimeric ruthenium(I) carbonyl phosphine complexes
[{Ru(CO)2(PPh3)(µ2-SR)]2.32 The 31P{1H} NMR spectrum of
3 displays a doublet resonance at δ 31.8 (2JRhP ) 5.6 Hz). The
observation of Rh-P coupling indicates the existence of a
metal-metal single bond between ruthenium and rhodium. The
structure of 3 is shown in Figure 2. The molecule contains two
five-coordinate metal atoms; the geometry around rhodium is
a two-legged piano stool, while that around ruthenium is a
distorted square pyramid in which the triphenylphosphine is
occupying the apical position. The Ru(1)-Rh(1) distance of
2.61329(12) Å is consistent with a single bond between the two
d7 metal centers,32,33 which was also indicated by the 31P{1H}
NMR spectrum (vide infra).
The dihydride complex 2 reacts with excess p-tolylacetylene
at room temperature to afford the corresponding alkynyl hydride
complex [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCTol-p)(PPh3)2]
(4a), which was formed as a mixture of cis and trans isomers
(8:2), isolated as cherry red microcrystalline solids, and
characterized by analytical and spectroscopic methods. The IR
spectrum of 4a exhibits a ν(CtC) band at 2071 cm-1, and the
1H NMR spectrum shows characteristic high-field resonances
1
of DCtCTol-p in C6D6 in a sealed NMR tube. The H NMR
spectrum showed formation of the alkynyl deuteride complex
[Cp*Rh(µ2-1,2-S2C6H4)(µ2-D)Ru(CtCTol-p)(PPh3)2] (4a-d)
(80%) and the alkene (Z)-p-TolCHdCHD (98%) (Scheme 2b).
This indicates a mechanism involving hydrogen transfer from
2 to the alkyne followed by oxidative addition of a second
equivalent of the alkyne to the dinuclear core of the low-valent
species “Cp*Rh(µ2-1,2-S2C6H4)Ru(PPh3)2”. Oxidative addition
of alkyne C-H bonds has been observed in several low-valent
transition-metal systems.36,37 The resulting alkynyl hydride
products are not very stable and often rearrange into vinylidene
tautomers.37 In multimetallic systems, on the other hand, alkynyl
hydride structures tend to be stable, since both the hydride and
(34) The asymmetric unit contains two crystallographically independent
molecules whose structures are essentially identical.
(35) For example, see: (a) Conner, D.; Jayaprakash, K. N.; Wells, M.
B.; Manzer, S.; Gunnoe, T. B.; Boyle, P. D. Inorg. Chem. 2003, 42, 4759-
4772. (b) Mene´ndez, C.; Morales, D.; Pe´rez, J.; Riera, V.; Miguel, D.
Organometallics 2001, 20, 2775-2781. (c) Touchard, D.; Haquette, P.;
Daridor, A.; Romero, A.; Dixneuf, P. H. Organometallics 1998, 17, 3844-
3852.
(32) Shiu, K.-B.; Wang, S.-L.; Liao, F.-L.; Chiang, M. Y.; Peng, S.-M.;
Lee, G.-H.; Wang, J.-C.; Liou, L.-S. Organometallics 1998, 17, 1790-
1797.
(33) (a) Cullen, W. R.; Talaba, A.; Rettig, S. J. Organometallics 1992,
11, 1, 3152. (b) Cabeza, J. A.; Mart´ınez-Garc´ıa, M. A.; Riera, V.; Ardura,
D.; Garc´ıa-Granda, S. Organometallics 1998, 17, 1471-1477. (c) Cabeza,
J. A.; Mart´ınez-Garc´ıa, M. A.; Riera, V.; Ardura, D.; Garc´ıa-Granda, S.;
Van der Maelen, J. F. Eur. J. Inorg. Chem. 1999, 1133, 3-1139.
(36) (a) Li, C.; Ogasawara, M.; Nolan, S.; Caulton, K. G. Organometallics
1996, 15, 4900-4903. (b) Werner, H.; Baum, M.; Schneider, D.; Wind-
mu¨ller, B. Organometallics 1994, 13, 1089-1097.
(37) (a) Bianchini, C.; Peruzzini, M.; Vacca, A.; Zanobini, F. Organo-
metallics 1991, 10, 3697-3707. (b) Bustelo, E.; Carbo´, J. J.; Lledo´s, A.;
Mereiter, K.; Puerta, M. C.; Valerga, P. J. Am. Chem. Soc. 2003, 125, 3311-
3321. (c) Werner, H.; Garcia Alonso, F. J.; Otto, H.; Wolf, J. Z. Naturforsch.,
B 1988, 43, 722-726.

A Dithiolate-Bridged Ru-Rh Dihydride Complex
Organometallics, Vol. 25, No. 4, 2006 985
Figure 4. Thermal ellipsoid plot (25% probability level) of
[Cp*Rh(µ2-η4:η2-1,3-(p-Tol)2C4H2)Ru(S2C6H4)(PPh3)] (5). Hydro-
gen atoms are omitted for clarity. Selected bond lengths (Å): Rh-
(1)-Ru(1), 2.7084(8); Rh(1)-C(1), 2.219(5); Rh(1)-C(2), 2.152-
(5); Rh(1)-C(3), 2.160(5); Rh(1)-C(4), 2.128(5); Ru(1)-S(1),
2.3039(15); Ru(1)-S(2), 2.3267(14); Ru(1)-P(1), 2.2983(16); Ru-
(1)-C(1), 2.074(5); Ru(1)-C(4), 1.978(5); C(1)-C(2), 1.420(7);
C(2)-C(3), 1.439(7); C(3)-C(4), 1.416(6).
Figure 3. Thermal ellipsoid plot (25% probability level) of
[Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCSiMe3)(PPh3)2] (4b). Hy-
drogen atoms are omitted for clarity. Selected bond lengths (Å)
and angles (deg): Rh(1)-Ru(1), 2.7708(7); Rh(1)-S(1), 2.3785-
(16); Rh(1)-S(2), 2.3587(18); Ru(1)-S(1), 2.4886(17); Ru(1)-
S(2), 2.4275(16); Ru(1)-C(1), 2.004(6); Ru(1)-P(1), 2.3070(16);
Ru(1)-P(2), 2.3233(16); C(1)-C(2), 1.221(10); C(2)-Si(1), 1.806-
(8); Ru(1)-C(1)-C(2), 169.6(6); C(1)-C(2)-Si(1), 171.0(7).
excess of p-tolylacetylene in THF at 60 °C afforded the
metallacyclopentadiene complex 5, which is most likely formed
via C-H reductive elimination to form a π-alkyne complex,
followed by its coupling with another 1 equiv of the alkyne.
The reaction is highly selective, and no other metal-containing
1
product was detected in the H NMR spectrum of the crude
reaction mixture. After chromatographic workup and recrystal-
lization, complex 5 was isolated in 10% yield39 as red needles
and characterized by NMR spectroscopy, elemental analysis,
and X-ray crystallography. As shown in Figure 4, the molecule
contains an almost planar ruthenacyclopentadiene moiety, which
is capped by a {Cp*Rh} fragment. The C-C bond lengths
within the ruthenacyclopentadiene framework are nearly con-
stant (1.416-1.439 Å). The Rh-Ru distance of 2.7084(8) Å
indicates a metal-metal bonding interaction, which may be
attributed to a dative bond from the 18-electron Rh(I) to 14-
electron Ru(IV) centers. The 1,2-benzenedithiolate ligand on
ruthenium is terminally bound. The Ru-S bond lengths are
2.2983(16) and 2.3039(15) Å, which are shorter by ∼0.1 Å as
compared to those observed for 18-electron ruthenium terminal
thiolate complexes23 and suggest a multiple-bond character
between ruthenium and sulfur atoms. The solution NMR data
are consistent with the solid-state structure. The 1H NMR
spectrum of 5 exhibits characteristic resonances assignable to
the metallacyclopentadiene R- and â-protons at δ 9.65 (m) and
5.50 (m), respectively. The 13C{1H} NMR spectrum of 5
Scheme 3
2
exhibits four pseudo-triplet resonances at δ 177.1 (1JRhC ≈ JPC
2
≈ 16.6 Hz), 149.5 (1JRhC ≈ JPC ≈ 17.6 Hz), 115.4 (1JRhC
≈
2JPC ≈ 7.4 Hz), and 95.9 (1JRhC ≈ JPC ≈ 5.2 Hz), of which the
first two can be assigned to the metallacyclopentadiene R-car-
bons and the last two to the â-carbons. These 13C NMR shifts
are analogous to those observed for other dinuclear metallacy-
2
(38) (a) Berenguer, J. R.; Bernechea, M.; Fornie´s, J.; Lalinde, E.; Torroba,
J. Organometallics 2005, 24, 431-438. (b) Crementieri, S.; Leoni, P.;
Marchetti, F.; Marchetti, L.; Pasquali, M. Organometallics 2002, 21, 2575-
2577. (c) Jime´nez, M. V.; Sola, E.; Martinez, A. P.; Lahoz, F. J.; Oro, L.
A. Organometallics 1999, 18, 1125-1136. (d) Smith, A. K. Trinuclear
Clusters of Ruthenium and Osmium: (ii) Hydrocarbon Ligands on Metal
Clusters. In ComprehensiVe Organometallic Chemistry II; Wilkinson, G.,
Stone, F. G. A., Abel, E. W., Eds.; Pergamon: Oxford, U.K., 1995; Vol. 7,
Chapter 13.2.3, p 772.
alkynyl moieties can be stabilized by bridging coordination.38
The present reaction represents a rare example of dinuclear
oxidative addition of alkyne that produces terminal alkynyl
moieties.38b,c
The alkynyl hydride complex 4a further reacts with substrates,
including alkynes and CO (Scheme 3). Treatment of 4a with
(39) The low isolated yield is due to difficulty in separating 5 from PPh3.

986 Organometallics, Vol. 25, No. 4, 2006
Takemoto et al.
Figure 6. Thermal ellipsoid plot (25% probability level) of
[Cp*Rh(µ2-H)(µ2-1,2-S2C6H4)Ru(CtCTol-p)(CO)(PPh3)2] (7). Hy-
drogen atoms, except for the bridging hydride, are omitted for
clarity. Selected bond lengths (Å) and angles (deg): Rh(1)-Ru-
(1), 2.9467(3); Rh(1)-S(1), 2.2844(7); Rh(1)-S(2), 2.3306(7); Ru-
(1)-S(1), 2.3974(7); Ru(1)-P(1), 2.3873(7); Ru(1)-P(2), 2.3563-
(7); Ru(1)-C(1), 2.074(3); Ru(1)-C(10), 1.898(3); C(1)-C(2),
1.208(4); C(10)-O(1), 1.154(3); Ru(1)-C(1)-C(2), 171.7(2);
C(1)-C(2)-C(3), 172.2(3).
Figure 5. Thermal ellipsoid plot (25% probability level) of
[Cp*Rh(µ2-1,2-S2C6H4)Ru(η6-C6Ph4H(p-Tol))] (6). Hydrogen atoms
are omitted for clarity. Selected bond lengths (Å): Rh(1)-Ru(1),
2.6151(5); Rh(1)-S(1), 2.3061(10); Rh(1)-S(2), 2.3224(9); Ru-
(1)-S(1), 2.3612(11); Ru(1)-S(2), 2.3654(10); Ru(1)-C(17),
2.190(4); Ru(1)-C(18), 2.196(4); Ru(1)-C(19), 2.191(4); Ru(1)-
C(20), 2.246(4); Ru(1)-C(21), 2.204(4); Ru(1)-C(22), 2.239(4).
crystallography. The IR spectrum of 7 exhibits ν(CtC)) and
ν(CO) bands at 2085 and 1967 cm-1, respectively. The 1H NMR
clopentadiene complexes40 and are shifted upfield as compared
to those of mononuclear ones.41 Treatment of 4a with excess
diphenylacetylene led to 1:2 coupling of p-tolylacetylene and
diphenylacetylene to form the η6-arene complex 6 (Scheme 3),
which was also isolated in 39% yield after chromatography on
silica gel, and structurally characterized. The structure of 6 is
shown in Figure 5. The two isoelectronic metal fragments
{Cp*Rh}+ and {(η6-arene)Ru}+ are linked together by the
bridging [S2C6H4]2- ligand, and the short metal-metal distance
(2.6161(5) Å) is consistent with a metal-metal single bond.
Cyclotrimerization of alkynes on transition-metal centers is
believed to proceed via oxidative coupling of two π-alkyne
ligands followed by insertion of a third alkyne molecule into
metal-carbon bonds of the resulting metallacycle.42 Formation
of the metallacyclopentadiene complex 5 and the η6-arene
complex 6 demonstrates the feasibility of alkyne reductive
elimination from the alkynyl hydride complex 4a.
1
spectrum of 7 shows a resonance at δ -14.84 (ddd, 1H, JRhH
2
) 26.6 Hz, JPH ) 26.6, 16.5 Hz) assignable to the bridging
hydride. The structure of 7 is shown in Figure 6. The hydride
ligand was found in the difference Fourier map. The two metal
centers are doubly bridged by a hydrogen and one of the
dithiolate sulfur atoms. Another thiolate moiety is terminally
bound to the rhodium center. The carbonyl and alkynyl ligands
are coordinated on ruthenium and are mutually trans to each
other. The Ru-Rh distance (2.9467(3) Å) is ca. 0.15 Å longer
than those of 1 and 4b, indicating the weakness of the bonding
interaction between the two metal centers.
Conclusions
The interaction between the rhodium dithiolate complex
[Cp*Rh(S2C6H4)] and the ruthenium hydride complex [RuHCl-
(PPh3)3] has been shown to be a straightforward route for the
new hydride- and dithiolate-bridged Ru-Rh heterobimetallic
complex 1, which was subsequently converted to the dihydride
complex 2. Complex 2 exhibited further chemistry resulting
from facile hydrogen loss, either by reductive elimination or
by transfer dehydrogenation. Thus, treatment of 2 with CO
induced reductive elimination of H2 to afford the lower-valent
carbonyl adduct 3, whereas the reaction of 2 with 1-alkynes
proceeded via transfer dehydrogenation of 2 followed by
oxidative addition of the alkynes to give the alkynyl hydride
complexes 4. The alkynyl hydride complex 4a has been shown
to incorporate carbon monoxide with retention of the alkynyl
hydride formulation, whereas it undergoes alkyne reductive
elimination and metallacycle formation upon heating with excess
alkynes. With these fundamental reactivities in hand, we are
currently exploiting the catalytic application of this heterodi-
nuclear system.
In contrast to the reaction of 4a with alkynes described above,
which induced C-H reductive elimination, treatment of 4a with
carbon monoxide led to incorporation of CO with retention of
the alkynyl hydride structure to afford the adduct 7 (Scheme
1
3). Complex 7 was obtained as a single stereoisomer (by H
NMR), isolated in 76% yield as reddish purple plates, and
characterized by NMR and IR spectroscopy as well as X-ray
(40) (a) Hirpo, W.; Curtis, M. D.; Kampf, J. W. Organometallics 1994,
13, 3360-3363. (b) Omori, H.; Suzuki, H.; Morooka, Y. Organometallics
1989, 8, 1576. (c) Campion, B. K.; Heyn, R. H.; Tilley, T. D. Organome-
tallics 1990, 9, 1106-1112.
(41) (a) Albers, M. O.; daWaal, D. J.; Lies, D. C.; Robinson, D. J.;
Singleton, E.; Wiege, M. B. J. Chem. Soc., Chem. Commun. 1986, 1680.
(b) Yi, C. S.; Torres-Lubian, J. R.; Liu, N.; Rheingold, A. L.; Guzei, I.
Organometallics 1998, 17, 1257-1259.
(42) (a) Kirchner, K.; Calhorda, M. J.; Schmid, R.; Veiros, L. F. J. Am.
Chem. Soc. 2003, 125, 11721-11729. (b) Hardesty, J. H.; Koerner, J. B.;
Albright, T. A.; Lee, G.-Y. J. Am. Chem. Soc. 1999, 121, 6055-6067.

A Dithiolate-Bridged Ru-Rh Dihydride Complex
Organometallics, Vol. 25, No. 4, 2006 987
2
NMR (CDCl3): δ 31.8 (d, JRhP ) 5.6 Hz). MS (FAB): m/z 798
Experimental Section
[M]+, 770 [M - CO]+, 742 [M - 2CO]+. IR (KBr, ν(CO)): 1985,
1921 cm-1
.
All manipulations were carried out using standard Schlenk
techniques under an atmosphere of nitrogen. Toluene, hexanes,
THF, and diethyl ether were distilled from sodium benzophenone
ketyl and degassed before use. Methanol and 2-propanol were
distilled from magnesium methoxide or calcium sulfate, respec-
tively, and degassed before use. Acetonitrile was distilled from P2O5
and degassed before use. Deuterated solvents were degassed by
three freeze-pump-thaw cycles and stored over 4A molecular
sieves. Cp*Rh(S2C6H4) and RuHCl(PPh3)3(toluene) were prepared
according to the literature.24,43 Other chemicals were obtained from
commercial sources.
Preparation of [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCTol-p)-
(PPh3)2] (4a). To a solution of 2 (1.10 g, 1.09 mmol) in THF (100
mL) was added p-tolylacetylene (247 mg, 2.13 mmol), and the
mixture was stirred at room temperature for 24 h. Concentration
of the solution to ca. 10 mL followed by slow diffusion of methanol
(30 mL) afforded a reddish purple microcrystalline solid, which
was collected by filtration and dried in vacuo: yield 737 mg (60%).
The product was obtained as an 8:2 mixture of cis and trans isomers.
Anal. Calcd for C61H57P2S2RuRh: C, 65.41; H, 5.13. Found: C,
1
66.10; H, 5.58. H NMR for cis-4a (C6D6): δ 7.8 (m, 12H, Ph),
NMR spectra were recorded on a JEOL ECP500 NMR spec-
trometer operating at 500.16 (1H), 202.48 (31P), and 125.78 (13C)
MHz; chemical shifts are referenced to internal solvent resonances
and are reported relative to tetramethylsilane or 85% phosphoric
acid. IR spectra were recorded on a JASCO FT-IR spectrometer.
Elemental analyses were performed on a Perkin-Elmer CHNS series
II microanalyzer. Mass spectra were measured on a JEOL JMS-
700 spectrometer.
7.7 (m, 3H, Ph), 7.59 (d, 2H, C6H4Me), 7.40 (d, 1H, S2C6H4), 7.11
(d, 2H, C6H4Me), 7.0 (m, 15H, Ph), 6.29 (d, 1H, S2C6H4), 6.27 (t,
1H, S2C6H4), 6.06 (t, 1H, S2C6H4), 2.24 (s, 3H, C6H4Me), 1.51 (s,
1
2
15H, Cp*), -9.65 (ddd, 1H, JRhH ) 26.6 Hz, JPH ) 26.6, 16.5
2
Hz, µ2-H). 31P{1H} NMR for cis-4a (C6D6): δ 52.9, 50.7 (d, JPP
) 25 Hz). 1H NMR for trans-2 (C6D6): δ 7.9-6.0 (m, aryl,
overlapped with the aryl resonances of cis-4a), 2.20 (s, 3H,
1
C6H4Me), 1.53 (s, 15H, Cp*), -10.88 (dt, 1H, JRhH ) 29.3 Hz,
2JPH ) 9.2 Hz, µ2-H). 31P{1H} NMR for trans-2 (C6D6): δ 55.1
Preparation of [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)RuCl(PPh3)2] (1).
To a stirred suspension of Cp*Rh(S2C6H4) (90 mg, 0.24 mmol) in
THF (50 mL) was added RuHCl(PPh3)3(toluene) (250 mg, 0.246
mmol), and the mixture was stirred overnight at room temperature
to form a deep blue solution. Concentration of the solution to ca.
10 mL followed by slow diffusion of diethyl ether (30 mL) afforded
deep blue plates, which were collected by filtration and dried in
vacuo: yield 210 mg (84%). Anal. Calcd for C52H50ClP2S2RuRh:
(s). MS (FAB): m/z 1120 [M]+. IR (KBr, ν(CtC)): 2071 cm-1
.
Preparation of [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)Ru(CtCSiMe3)-
(PPh3)2] (4b). To a solution of 2 (100 mg, 0.0994 mmol) in THF
(10 mL) was added (trimethylsilyl)acetylene (19 mg, 0.19 mmol),
and the mixture was stirred at room temperature for 19 h. Volatiles
were removed in vacuo, and the residue was recrystallized from
toluene-acetonitrile (2 mL/10 mL) to afford dark red plates, which
were collected by filtration and dried in vacuo: yield 82 mg (75%).
Anal. Calcd for C57H59SiP2S2RuRh: C, 62.11; H, 5.40. Found: C,
62.02; H, 5.38. 1H NMR (C6D6): δ 7.86-7.05 (m, 30H, Ph), 6.90,
6.24, 6.22, 6.03 (m, 1H each, S2C6H4), 1.52 (s, 15H, Cp*), 0.50 (s,
1
C, 60.03; H, 4.84. Found: C, 60.24; H, 4.96. H NMR (CDCl3):
δ 7.22 (m, 12H, Ph), 7.17 (m, 6H, Ph), 7.11 (m, 2H, S2C6H4), 7.03
(m, 12H, Ph), 6.60 (m, 2H, S2C6H4), 1.65 (s, 15H, Cp*), -17.05
1
2
(dt, 1H, JRhH ) 25.7 Hz, JPH ) 12.8 Hz, µ2-H). 31P{1H} NMR
(CDCl3): δ 50.07 (s). MS (FAB): m/z 1039 [M - H]+.
1
2
9H, SiMe3), -9.76 (ddd, 1H, JRhH ) 25.7 Hz, JPH ) 25.7, 16.5
Preparation of [Cp*Rh(µ2-1,2-S2C6H4)(µ2-H)RuH(PPh3)2] (2).
A mixture of 1 (192 mg, 0.185 mmol) and KOH (103 mg, 1.84
mmol) in 2-propanol (20 mL) was stirred at 60 °C for 90 min. The
color changed from blue to red. Volatiles were removed in vacuo,
and the residue was extracted with toluene (30 mL). Concentration
of the extract to ca. 10 mL followed by slow diffusion of methanol
(30 mL) afforded a reddish purple microcrystalline solid, which
was collected by filtration and dried in vacuo: yield 134 mg (72%).
The product was obtained as an 8:2 mixture of cis and trans isomers.
Anal. Calcd for C52H51P2S2RuRh: C, 62.08; H, 5.11. Found: C,
62.11; H, 5.38. 1H NMR for cis-2 (C6D6): δ 7.78-6.38 (m, 34H,
aryl), 1.50 (s, 15H, Cp*), -9.79, -14.00 (m, 1H each, µ2-H and
RuH). 31P{1H} NMR for cis-2 (C6D6): δ 68.8, 65.4 (d, 2JPP ) 11.3
Hz). 1H NMR for trans-2 (C6D6): δ 7.78-6.38 (m, aryl, overlapped
with the aryl resonances of cis-2), 1.64 (s, 15H, Cp*), -8.23, -8.53
(m, 1H each, µ2-H and RuH). 31P{1H} NMR for trans-2 (C6D6):
δ 70.3 (s). MS (FAB): m/z 1005 [M - H]+.
Hz, µ2-H). 31P{1H} NMR (C6D6): δ 52.6, 49.4 (d, 2JPP ) 26 Hz).
IR (KBr, ν(CtC)): 1994 cm-1
.
Preparation of [Cp*Rh(µ2-η4:η2-1,3-(p-Tol)2C4H2)Ru(S2C6H4)-
(PPh3)] (5). To a solution of 4a (270 mg, 0.241 mmol) in THF (20
mL) was added p-tolylacetylene (156 mg, 1.34 mmol), and the
mixture was stirred at 60 °C for 16 h. The solution was concentrated
to ca. 2 mL and then loaded onto a short silica gel column (1 cm
o.d., 10 cm). Elution with toluene gave a red band, which was
collected, concentrated to ca. 2 mL, and then layered with methanol
(10 mL). The red needlelike crystals formed were collected by
filtration and dried in vacuo: yield 25 mg (10%). The crystals
contain one solvating toluene per molecule of 5. Anal. Calcd for
C52H50PS2RuRh‚C7H8: C, 66.47; H, 5.48. Found: C, 67.10; H, 5.74.
1H NMR (CDCl3): δ 9.65 (m, 1H, (p-Tol)CCHC(p-Tol)CH), 8.21
(m, 2H, aryl), 7.7-7.0 (m, 25H, aryl), 5.50 (m, 1H, (p-Tol)CCHC-
(p-Tol)CH), 2.35, 2.33 (s, 3H each, C6H4Me), 1.20 (s, 15H, Cp*).
31P{1H} NMR (CDCl3): δ 62.4 (s). 13C{1H} NMR (CDCl3): δ
1
2
Preparation of [Cp*Rh(µ2-1,2-S2C6H4)Ru(CO)2(PPh3)] (3). To
a solution of 2 (200 mg, 0.199 mmol) in THF (10 mL) was added
carbon monoxide (9 mL, ca. 2 equiv), and the mixture was stirred
at room temperature for 4 h. The color changed from red to brown.
Volatiles were removed in vacuo, and the residue was recrystallized
from toluene-methanol (2 mL/10 mL) to afford dark red plates,
which were collected by filtration and dried in vacuo: yield 127
mg (80%). Anal. Calcd for C36H34O2PS2RuRh: C, 54.20; H, 4.30.
177.1 (pseudo t, JRhC ≈ JPC ≈ 16.6 Hz, (p-Tol)CCHC(p-Tol)-
1
2
CH), 149.5 (pseudo t, JRhC ≈ JPC ≈ 17.6 Hz, (p-Tol)CCHC(p-
3
Tol)CH), 115.4 (pseudo t, 1JRhC ≈ JPC ≈ 7.4 Hz, (p-Tol)CCHC(p-
3
Tol)CH), 95.9 (pseudo t, 1JRhC ≈ JPC ≈ 5.2 Hz, (p-Tol)CCHC(p-
Tol)CH), 159.7, 145.4, 136.8, 136.0, 135.4, 134.9, 134.1, 133.6,
131.4, 130.4, 130.0, 128.8, 128.5, 128.3, 128.0, 127.7, 126.9, 125.5
1
(s, aryl), 98.2 (d, JRhC ) 18 Hz, C5Me5), 21.4, 21.3 (s, C6H4Me),
9.6 (s, C5Me5). MS (FAB): m/z 974 [M]+.
1
Preparation of [Cp*Rh(µ2-1,2-S2C6H4)Ru(η6-C6Ph4H(p-Tol))]
(6). To a solution of 4a (200 mg, 0.179 mmol) in THF (20 mL)
was added diphenylacetylene (159 mg, 0.893 mmol), and the
mixture was stirred at 60 °C for 16 h. The mixture was concentrated
to ca. 2 mL and then loaded onto a short silica gel column (1 cm
o.d., 10 cm). Elution with toluene gave a red band, which was
collected and evaporated to dryness. Recrystallization of the residue
from THF-methanol (3 mL/12 mL) afforded red blocks, which
Found: C, 53.58; H, 3.95. H NMR (C6D6): δ 7.68 (m, 6H, Ph),
7.01 (m, 9H, Ph), 6.80 (m, 2H, S2C6H4), 6.03 (m, 2H, S2C6H4),
2.03 (s, 15H, Cp*). 13C{1H} NMR (C6D6): 206.2 (dd, 2JRhC ) 2.9
2
1
Hz, JPC ) 2.9 Hz, CO), 150.4 (d, JPC ) 4.8 Hz, aryl), 137.0 (s,
aryl), 136.7 (s, aryl), 133.5 (m, aryl), 129.2 (m, aryl), 123.7 (s,
aryl), 94.6 (d, JRhC ) 6.7 Hz, C5Me5), 11.2 (s, C5Me5). 31P{1H}
1
(43) Schunn, R. A.; Wonchoba, E. R. Inorg. Synth. 1971, 13, 131-134.

988 Organometallics, Vol. 25, No. 4, 2006
Table 1. Crystallographic Data for 1, 3, 4b, 5‚(toluene), 6, and 7
Takemoto et al.
1
3
4b
5‚(toluene)
6
7
formula
C52H50ClP2S2-
RuRh
C36H34O2PS2-
RuRh
C57H59SiP2S2-
RuRh
C59H58PS2-
RuRh
C53H47S2RuRh
C62H57OP2S2-
RuRh
Mr
T (K)
1040.41
296
797.70
296
1102.17
296
1066.12
296
952.01
296
1148.12
296
size (mm)
0.80 × 0.30 ×
0.50 × 0.15 ×
0.70 × 0.60 ×
0.50 × 0.10 ×
0.50 × 0.40 ×
0.60 × 0.20 ×
0.01
0.01
0.30
0.10
0.30
0.10
cryst syst
space group
Z
orthorhombic
Pca21
4
monoclinic
P21/n
4
monoclinic
P21
4
monoclinic
P21/n
4
triclinic
P1h
2
monoclinic
P21/c
4
a (Å)
b (Å)
c (Å)
19.5760(16)
12.9958(17)
18.3713(16)
12.401(9)
22.984(12)
13.023(6)
13.1118(12)
21.503(3)
19.348(2)
11.042(3)
28.500(8)
15.871(5)
13.4280(14)
13.4077(17)
13.450(2)
95.065(5)
100.779(5)
108.421(5)
2228.4(5)
1.419
0.838
21 389
10 103
0.966
12.0433(6)
23.0234(11)
19.3711(12)
R (deg)
â (deg)
γ (deg)
V (Å3)
113.77(4)
94.862(5)
92.80(2)
90.638(3)
4673.8(8)
1.479
0.926
41 576
9983
1.024
3397(3)
1.560
1.131
32 734
7766
0.930
5435.4(10)
1.347
0.774
50 617
23 938
0.937
0.0517
0.1484
4989(2)
1.419
0.787
48 834
11 433
1.020
0.0713
0.1181
5370.8(5)
1.420
0.767
49 209
12 098
1.001
0.0356
0.0800
D
calcd (g/cm3)
µ (mm-1
)
no. of rflns collected
no. of unique rflns
GOF on F2
R1 (I > 2σ(I))a
wR2 (all data)b
0.0498
0.1170
0.0534
0.1039
0.0430
0.1036
2
2
2
a R1 ) ∑||Fo| - |Fc||/∑|Fo|. b wR2 ) [∑(w(Fo - Fc )2/∑w(Fo )2]1/2
.
structures were solved by direct methods and refined on F2 by full-
matrix least-squares methods with the SHELX97 program pack-
age.46 Anisotropic refinement was applied to all non-hydrogen
atoms. Hydrogen atoms were located at the calculated positions
and treated as riding models, except for the hydride ligand in 1,
which was found in the final difference Fourier map and refined
isotropically. Crystallographic data are summarized in Table 1.
were collected by filtration and dried in vacuo: yield 66 mg (39%).
Anal. Calcd for C53H47S2RuRh: C, 66.86; H, 4.98. Found: C,
66.81; H, 5.21. 1H NMR (C6D6): δ 8.24-6.54 (m, 29H, aryl), 2.01
(s, 3H, C6H4Me), 1.61 (s, 15H, Cp*). MS (FAB): m/z 952 [M]+.
Preparation of [Cp*Rh(µ2-H)(µ2-1,2-S2C6H4)Ru(CtCTol-p)-
(CO)(PPh3)2] (7). A 20 mL Schlenk flask was charged with 4a
(97 mg, 0.086 mmol) and THF (10 mL). After the solution was
frozen at -196 °C, the flask was evacuated, warmed to room
temperature, and then filled with atmospheric carbon monoxide.
The mixture was stirred at room temperature for 18 h and
concentrated in vacuo to ca. 2 mL. Slow diffusion of methanol (30
mL) into the concentrated reaction solution afforded reddish purple
plates, which were collected by filtration and dried in vacuo: yield
75 mg (76%). Anal. Calcd for C62H57OP2S2RuRh: C, 64.86; H,
5.00. Found: C, 64.19; H, 5.35. 1H NMR (C6D6): δ 7.83 (m, 14H,
Acknowledgment. Financial support from the Ministry of
Education, Science, Sports, and Culture of Japan, including a
Grant-in-Aid for Scientific Research on Priority Areas (No.
17036059 “Chemistry of Coordination Space”), is appreciated.
We are also grateful to the Toyota Motor Corp. for financial
support.
Supporting Information Available: Crystallographic data in
CIF format. This material is available free of charge via the Internet
at http://pubs.acs.org.
aryl), 7.12-6.96 (m, 22H, aryl), 6.82, 6.56 (m, 1H each, aryl), 2.16
1
(s, 3H, C6H4Me), 1.66 (s, 15H, Cp*), -14.84 (ddd, 1H, JRhH
)
26.6 Hz, JPH ) 26.6, 16.5 Hz, µ2-H). 31P{1H} NMR (C6D6): δ
2
OM050871N
41.3, 29.4 (d, JPP ) 20 Hz). MS (FAB): m/z 1148 [M]+. IR
2
(KBr): ν(CtC)) 2085 cm-1, ν(CO) 1967 cm-1
.
(44) PROCESS-AUTO, Automatic Data Acquisition and Processing
Package for Imaging Plate Diffractometer; Rigaku Corp., Tokyo, Japan,
1998.
(45) Higashi, T. ABSCOR, Empirical Absorption Correction based on
Fourier Series Approximation; Rigaku Corp., Tokyo, Japan, 1995.
(46) Sheldrick, G. M. SHELX97, Program for Crystal Structure Deter-
mination; University of Go¨ttingen, Go¨ttingen, Germany, 1997.
X-ray Crystallography. Reflection data were collected at 296
K with a Rigaku RAXIS Rapid diffractometer equipped with an
imaging plate detector. The frame data were processed using the
Rigaku PROCESS-AUTO program,44 and the reflection data were
corrected for absorption with the ABSCOR program.45 The