Reaction of a heterobimetallic polyhydrido cluster, [Cp*Ru(μ-H) 4OsCp*] (Cp* = η5-C5Me 5), with diphenylacetylene. Regioselective C-H bond activation at the osmium center

Article abstract of DOI:10.1021/om700606q

The reactivity of a heterobimetallic polyhydrido complex [Cp*Ru(μ-H)₄OsCp*] (1) toward diphenylacetylene is studied to elucidate the roles of each metal atom in the substrate activation step. The reaction of 1 with an equivalent of diphenylacetylene exclusively produces a η²-frans-stilbene complex [Cp*Ru(μ-H) ₂(μ-trans-PhHC=CHPh)OsCp*] (8), in which trans-stilbene is coordinated to the osmium metal by way of the η²-cis-stilbene complex [Cp*Ru(μ-H)₂(μ-cis-PhHC=CHPh)OsCp*] (10). Treatment of 1 with an excess amount of diphenylacetylene yields [Cp*Ru(μ-H)(μ-η¹:n²-cis-PhC=CHPh)(trans- PhHC= C HPh)OsCp*] (11) via complex 8. Intermediacy of 8 in the formation of 11 is confirmed by the reaction of 8 with diphenylacetylene. Thermolysis of 11 in C₆D₆ at 50 °C generates a μ-perpendicularly coordinated diphenylacetylene complex [Cp*Ru(μ-H)₂(μ- η²:η²-PhCCPh)OsCp*] (12) and a benzo-osmacyclopentadiene complex [Cp*Os(μ-PhC=CH-C₆H ₄-)H₂RuCp*] (13) together with trans-stilbene. Complex 8 is converted into 13 even in the absence of added diphenylacetylene. Upon heating of 8 in THF, 13 is formed as a result of the C(sp²)-H bond cleavage and subsequent intramolecular activation of the C(ortho)-H bond at the osmium center. The molecular structures of [(C₅Me ₄Et)Ru(μ-H)₂(μ-trans-PhHC=CHPh)OsCp*] (80′, [(C₅Me₄Et)Ru(μ-H)(μ-η¹: η²-cis-PhC=CHPh)(oros-Ph HC=CHPh)OsCp*] (11′), 12, [Cp*Os(μ-PhC= CH-C ₆H₄-)H₂Ru(C₅Me₄Et)] (13′), and [Cp*Os(μ-PhC=CH-C₆H₄-)H ₂OsCp*] (15) are determined by X-ray studies.

Full text of DOI:10.1021/om700606q

Organometallics 2007, 26, 6329-6337
6329
Reaction of a Heterobimetallic Polyhydrido Cluster,
[Cp*Ru(µ-H)4OsCp*] (Cp* ) η5-C5Me5), with Diphenylacetylene.
Regioselective C-H Bond Activation at the Osmium Center
Takanori Shima,† Toshiaki Ichikawa, and Hiroharu Suzuki*
Department of Applied Chemistry, Graduate School of Science and Engineering, Tokyo Institute of
Technology, O-okayama, Meguro-ku, Tokyo 152-8552, Japan
ReceiVed June 21, 2007
The reactivity of a heterobimetallic polyhydrido complex [Cp*Ru(µ-H)4OsCp*] (1) toward dipheny-
lacetylene is studied to elucidate the roles of each metal atom in the substrate activation step. The reaction
of 1 with an equivalent of diphenylacetylene exclusively produces a η2-trans-stilbene complex [Cp*Ru-
(µ-H)2(µ-trans-PhHCdCHPh)OsCp*] (8), in which trans-stilbene is coordinated to the osmium metal
by way of the η2-cis-stilbene complex [Cp*Ru(µ-H)2(µ-cis-PhHCdCHPh)OsCp*] (10). Treatment of 1
with an excess amount of diphenylacetylene yields [Cp*Ru(µ-H)(µ-η1:η2-cis-PhCdCHPh)(trans-PhHCd
C HPh)OsCp*] (11) via complex 8. Intermediacy of 8 in the formation of 11 is confirmed by the reaction
of 8 with diphenylacetylene. Thermolysis of 11 in C6D6 at 50 °C generates a µ-perpendicularly coordinated
diphenylacetylene complex [Cp*Ru(µ-H)2(µ-η2:η2-PhCCPh)OsCp*] (12) and a benzo-osmacyclopentadiene
complex [Cp*Os(µ-PhCdCH-C6H4-)H2RuCp*] (13) together with trans-stilbene. Complex 8 is converted
into 13 even in the absence of added diphenylacetylene. Upon heating of 8 in THF, 13 is formed as a
result of the C(sp2)-H bond cleavage and subsequent intramolecular activation of the C(ortho)-H bond
at the osmium center. The molecular structures of [(C5Me4Et)Ru(µ-H)2(µ-trans-PhHCdCHPh)OsCp*]
(8′), [(C5Me4Et)Ru(µ-H)(µ-η1:η2-cis-PhCdCHPh)(trans-Ph HCdCHPh)OsCp*] (11′), 12, [Cp*Os(µ-PhCd
CH-C6H4-)H2Ru(C5Me4Et)] (13′), and [Cp*Os(µ-PhCdCH-C6H4-)H2OsCp*] (15) are determined by
X-ray studies.
transition metal complexes. Many precedents for the reaction
of heterobimetallic complexes, such as regioselective coordina-
tion of alkynes or insertion reaction of alkynes into an M-H
or an M-CO bond, have been reported thus far.3 Mathieu et
al. have demonstrated regioselective insertion of a terminal
alkyne into an Ru-H bond of [(PPh3)2(CO)Re(µ-H)3Ru-
(PPh3)2(CH3CN)] and C-H bond cleavage of the second alkyne
molecule. The reaction finally resulted in the formation of a
µ-alkene-acetylido complex [(PPh3)2(CO)Re(µ-RHdCH2)(µ-
H)2Ru(PPh3)2(CtCR)].4 This reaction proceeded site-selec-
tively, in which the rhenium center took a part of a coordination
site of the formed alkene and the ruthenium center played the
role of an activation site. Also, C-H bond of the alkene was
exclusively split at the ruthenium center.
Introduction
We have recently reported the synthesis and the structure of
the heterobimetallic polyhydrido complex [Cp*Ru(µ-H)4OsCp*]
(1) (Cp* ) η5-C5Me5) and demonstrated typical examples of
the site-selective coordination and activation of ethylene.1 A
divinyl-ethylene complex [Cp*Os(µ-η1:η2-CHdCH2)2(η2-CH2d
CH2)RuCp*] (2) was exclusively formed as a result of site-
selective C-H bond cleavage at the osmium center. In this
reaction, the ruthenium center plays the role of coordination
site. Thus, the metal centers of the heterometallic clusters can
play mutually complementary roles, as a binding site and an
activation site.
Another interesting aspect of the heterometallic clusters is
their unique reactivity that reflects the combination of the metals.
For example, thermolysis of complex 2 gives bis(ethylidyne)
complex [Cp*Ru(µ-CCH3)2OsCp*] (4), while the thermolysis
of homonuclear ruthenium divinyl-ethylene complex [Cp*Ru-
(µ-η1:η2-CHdCH2)2(η2-CH2dCH2)RuCp*] (3) gives ruthena-
cyclopentadiene complex 5 (Scheme 1).2 Thus, the two dinuclear
tetrahydrido complexes, 1 and [Cp*Ru(µ-H)4RuCp*] (6), are
appropriate probes for understanding the role of each metal
center in the heterometallic reaction field.
According to the vertical trends associated with the transition
elements, the metal-metal and metal-ligand bond enthalpies
(3) (a) George, D. S. A.; Hilts, R. W.; McDonald, R.; Cowie, M.
Organometallics 1999, 18, 5330. (b) George, D. S. A.; McDonald, R.;
Cowie, M. Organometallics 1998, 17, 2553. (c) Sterenberg, B. T.;
McDonald, R.; Cowie, M. Organometallics 1997, 16, 2297. (d) Sterenberg,
R. T.; Hilts, R. W.; Moro, G.; McDonald, R.; Cowie, M. J. Am. Chem.
Soc. 1995, 117, 245. (e) Chetcuti, M. J.; Grant, B. E.; Fanwick, P. E.
Organometallics 1996, 15, 4389. (f) Chetcuti, M. J.; Grant, B. E.; Fanwick,
P. E. Organometallics 1995, 14, 2937. (g) Matsuzaka, H.; Ichikawa, K.;
Ishioka, T.; Sato, H.; Okubo, T.; Ishii, T.; Yamashita, M.; Kondo, M.;
Kitagawa, S. J. Organomet. Chem. 2000, 596, 121. (h) Yasuda, T.; Fukuoka,
A.; Hirano, M.; Komiya, S. Chem. Lett. 1998, 29. (i) Knorr, M.; Strohmann,
C. Eur. J. Inorg. Chem. 2000, 241. (j) Cao, D. H.; Stang, P. J.; Arif, A. M.
Organometallics 1995, 14, 2733. (k) Stang, P. J.; Cao, D. Organometallics
1993, 12, 996. (l) Hart, I. J.; Jardin, A. E.; Jeffery, J. C.; Stone, F. G. A. J.
Organomet. Chem. 1988, 341, 391. (m) Davies, D.; Parrott, M. J.; Sherwood,
P.; Stone, F. G. A. J. Chem. Soc., Dalton Trans. 1987, 1201. (n) Garcia,
M. E.; Tran-Huy, N. H.; Jeffery, J. C.; Sherwood, P.; Stone, F. G. A. J.
Chem. Soc., Dalton Trans. 1987, 2201.
Alkynes are highly reactive with transition metal complexes.
Alkynes are, therefore, probes to test the reactivity of the
* To whom correspondence should be addressed. Phone: (+81)-3-5734-
2148. Fax: (+81)-3-5734-3913. E-mail: hiroharu@n.cc.titech.ac.jp.
† Current address: Organometallic Chemistry Laboratory, RIKEN (The
Institute of Physical and Chemical Research), Hirosawa 2-1, Wako, Saitama
351-0198, Japan.
(1) Shima, T.; Suzuki, H. Organometallics 2005, 24, 3939.
(2) Suzuki, H.; Omori, H.; Lee, D. H.; Yoshida, Y.; Fukushima, M.;
Tanaka, M.; Moro-oka, Y. Organometallics 1994, 13, 1129.
(4) He, Z.; Plasseraud, L.; Moldes, I.; Dahan, F.; Neibecker, D.; Etienne,
M.; Mathieu, R. Angew. Chem., Int. Ed. Engl. 1995, 34, 916.
10.1021/om700606q CCC: $37.00 © 2007 American Chemical Society
Publication on Web 10/27/2007

6330 Organometallics, Vol. 26, No. 25, 2007
Scheme 1. Thermolysis of the Divinyl-ethylene Complexes 2 and 3
Shima et al.
increase down a column of the periodic table and the complexes
become more substitutionally inert. Complex 1 is, therefore,
expected to form more stable intermediates during the reaction
than those formed in the reaction of complex 6. Here, we report
the reaction of 1 with diphenylacetylene. The reactivity of 1
was compared to those of complex 6 and diosmium complex
[Cp*Os(µ-H)4OsCp*] (7).
respect to the Ru-Os vector, and two hydrido ligands bridge
the two metals. Although the Ru1-C8 (2.56(1) Å) and Ru1-
H8 (2.2(1) Å) distances are somewhat long, they are still in the
range of those reported for agostic interactions.6 The Ru1-Os1
distance of 2.597(1) Å is longer than the triple bond (2.4663-
(5) Å) in 1 and corresponds to a Ru-Os double bond.
The X-ray diffraction study clearly indicated that the ruthe-
nium has agostic interaction with one of the olefinic C-H
moiety of the coordinated trans-stilbene. Interestingly, complex
8 is fluxional in solution. The 1H NMR spectrum exhibited two
singlet signals of the Cp* groups at δ 1.76 (15H) and 1.67 (15H)
ppm. The signals of the hydrides were observed at δ -15.25
(1H) and -17.67 (1H) ppm. Doublet signals of the olefinic
protons of the trans-stilbene appeared at δ 5.51 and 4.53 ppm,
and the coupling constant (JHH) of 6.8 Hz is typical for the
coordinated trans-alkene.
Results and Discussion
Reaction of [Cp*Ru(µ-H)4OsCp*] (1) with Diphenylacety-
lene. Complex 1 smoothly reacted with an equimolar amount
of diphenylacetylene in toluene at room temperature to generate
a η2-trans-stilbene complex [Cp*Ru(µ-H)2(µ-trans-PhHCd
CHPh)OsCp*] (8) in 88% yield, in which the trans-stilbene
molecule was coordinated both to the osmium center in a
π-fashion and to the ruthenium through agostic C-H-Ru
interaction (eq 1). The structure was confirmed by means of an
X-ray diffraction study (vide infra). Previously, we reported that
complex 6 reacted with 2 molar amounts of diphenylacetylene
at room temperature to yield µ-η2:η2-alkyne complex [Cp*Ru-
(µ-H)2(µ-η2:η2-PhCCPh)RuCp*] (9) together with the formation
of trans-stilbene (eq 2).5 The reaction of 1 proceeded slower
than that of 6, and the 1:1-adduct 8 was able to be isolated,
while the corresponding intermediary 1:1-adduct was not
observed in the reaction of 6, even at low temperature.
1
Not the H but the 13C NMR spectral data were crucial for
the determination of the structure of 8 in solution. The signals
of the olefinic carbons in the trans-stilbene appeared at δ 39.2
(JCH ) 147.8 Hz) and 20.1 (JCH ) 132.4 Hz) ppm. These two
signals were assigned to the carbon bound to the ruthenium and
that bound to the osmium, respectively. These assignments of
the 13C signals for the olefinic carbons were based on the
chemical shifts of the coordinated ethylene in complex 2 and
3.1,2 X-ray diffraction study revealed that the structures of 2
and 3 were almost identical, and the ethylene molecule was
coordinated to the osmium atom in 2. The difference in the 13
C
chemical shift of ethylene ligand would, therefore, reflect the
difference of electronic properties between the ruthenium and
the osmium. The signals of ethylene appeared at δ 33.1 and
To avoid the difficulty in the assignment of the metals
stemming from their disordered structure, the X-ray diffraction
study was carried out using a single crystal of [(C5Me4Et)Ru-
(µ-H)2(µ-trans-PhHCdCHPh)OsCp*] (8′), which was obtained
from the reaction of a mixed-ligand complex [(C5Me4Et)Ru-
(µ-H)4OsCp*] (1′) with diphenylacetylene. The X-ray diffraction
study established the structural identity of 8′, in which trans-
stilbene bridged the ruthenium and the osmium atoms through
the π-coordination and the agostic C-H-Ru interaction,
respectively. The molecular structure of 8′ confirmed by an
X-ray study is illustrated in Figure 1, with selected bond lengths,
angles, and torsion angles. The ORTEP drawing of 8′ clearly
shows that trans-stilbene is bound to the osmium atom through
a π(CC) orbital. The two Cp* ligands are mutually cis with
Figure 1. ORTEP drawing of 8′, with thermal ellipsoids at the
25% probability level. One disordered C5Me4Et ligand on Ru1 has
been omitted for clarity. Selected bond lengths (Å), angles, and a
torsion angle (deg): Ru1-Os1, 2.597(1); Os1-C7, 2.15(1); Os1-
C8, 2.15(1); Ru1-C8, 2.56(1); C7-C8, 1.43(2); Ru1-H8, 2.2(1);
C8-H8, 1.0 (1); C7-H7, 0.9 (1); Os1-C7-C8, 70.7(7); Os1-
C8-C7, 70.4(7); Os1-C8-Ru1, 66.3(3); C1-C7-C8, 124(1);
C7-C8-C9, 120(1); C1-C7-C8-C9, 134(1).
(5) Omori, H.; Suzuki, H.; Kakigano, T.; Moro-oka, Y. Organometallics
1992, 11, 989.

Reaction of a Polyhydrido Cluster with Diphenylacetylene
Scheme 2. Plausible Fluxionality in 8
Organometallics, Vol. 26, No. 25, 2007 6331
Scheme 3 . Isomerization Reaction from Complex 10 to 8
48.9 ppm for 2 and 3, respectively. The signal of the ethylene
CHPh)(PiPr2(C(CH3)dCH2))].7 The resulting intermediate E
having an Os-H-C agostic interaction would be equilibrated
with regioisomer 8 that had a Ru-H-C agostic interaction.
Complex 10 was identified as follows. Two singlet signals
of the hydrides and olefinic protons of the coordinated stilbene
were observed at δ -16.31 (2H) and 3.33 (2H) ppm, respec-
tively. In the 13C NMR spectrum, the signal of two olefinic
carbons of the coordinated stilbene was observed to be
equivalent at δ 38.2 (JCH ) 146.9 Hz) ppm. These NMR
data clearly show that 10 has a mirror plane along with the
Ru-Os vector, and, therefore, the coordinated stilbene has cis
geometry.
Two singlet signals appearing at δ 1.77 (15H) and 1.46 (15H)
ppm were ascribed to the C5Me5 group bound to the osmium
and to the ruthenium, respectively, by comparing the data to
that of a labeled compound [(C5Me4Et)Ru(µ-H)4Os(C5Me5)]
(1′).
ligand of 2 appeared more in the upper field than that of 3 by
ca. 16 ppm. According to this result, the signal that appeared
at δ 20.1 ppm in the 13C NMR spectrum of 8 was unambigu-
ously ascribed to the carbon atom bound to the osmium, and
that observed at δ 39.2 was assigned to the carbon bound to
the ruthenium. The shift of δ 20.1 is also comparable to the
value for the trans-stilbene complex [OsH(η5-C5H4CH3)(η2-(E)-
PhCHdCHPh)(PiPr2(C(CH3)dCH2))] δ 25.2 and 24.6 ppm.7
It is noteworthy that the signal at δ 20.1 couples with a proton
signal at δ 5.51. The coupling constant of 132.4 Hz is
significantly smaller than that for olefinic carbon, and the small
JCH value suggests the presence of a weak agostic C-H-Os
interaction in solution in sharp contrast to the C-H-Ru
interaction in solid state.
A spin saturation transfer experiment in tetrahydrofuran-d8
proved the site-exchange between the two olefinic protons of
the stilbene ligand and the two hydrido ligands. Irradiation at
the resonance positions of the hydride signals at δ -15.40 and
-17.87 at 40 °C resulted in a reduction of the intensity of the
olefinic protons of the coordinated trans-stilbene at δ 4.34 and
5.22. This strongly suggests a site-exchange process among the
olefinic protons and the hydrido ligands by way of the C-H-M
interaction, and subsequent oxidative addition of each metal
atom (Scheme 2).
To elucidate the mechanism for the formation of 8, the
reaction of 1 with excess diphenylacetylene (>10 equiv) in
Between the two possible structures for 10, 10-in and 10-
out, the latter is highly plausible. Two phenyl groups of cis-
stilbene would occupy the outside of the domain interposed
between the two metals to avoid steric repulsion toward the
C5Me5 group on the osmium. Significant upfield shift of the
1H NMR signal for the C5Me5 group on the ruthenium is
probably due to the aromatic ring current effect of the phenyl
groups of the stilbene ligand.
1
toluene-d8 at -5 °C was monitored by means of H NMR
spectroscopy. Along with a decrease in 1, the intensities of the
signals for an intermediary cis-stilbene complex 10 increased.
The signals for 1 disappeared after 1 h, and the yield of 10
reached 89%. The reaction temperature was then raised to room
temperature and kept there. Along with the reaction time, a
significant decrease in the intensities of the signals for 10 and
a progressive increase in those for 8 were observed. After 1 h,
10 was completely consumed, and the yield of 8 reached ca.
90%. This result obviously indicates that 8 is formed by way
of 10 (Scheme 3).
The conversion of geometry of the coordinated stilbene from
cis to trans is explained by the reaction paths that involved syn
insertion of cis-stilbene into the Ru-H bond and subsequent
rotation of the CH2Ph group around the C-C single bond
followed by â-H elimination. A similar process was observed
in the osmium complex [OsH(η5-C5H4CH3)(η2-(Z)-PhCHd
The reaction of 1 with diphenylacetylene was substantially
affected by the amount of added acetylene. While the reaction
of 1 with an equimolar amount of diphenylacetylene at room
temperature gave 8, the reaction of 1 with an excess amount (8
equiv) of diphenylacetylene at room temperature for 8 h resulted
in the formation of a cis-η1:η2-alkenyl-η2-trans-stilbene complex
[Cp*Ru(µ-H)(µ-η1:η2-cis-CPhdCHPh)(trans-PhHCdCHPh)-
OsCp*] (11), which was isolated in 69% yield as a black
crystalline solid after recrystallization from THF/MeOH (eq 3).
Complex 11 was also prepared by the reaction of 8 with an
excess amount of diphenylacetylene at room temperature. This
result clearly shows that 8 is an intermediate of the path from
(6) Brookhart, M.; Green, M. L. H. J. Organomet. Chem. 1983, 250,
395.
(7) Baya, M.; Buil, M. L.; Esteruelas, M. A.; On˜ate, E. Organometallics
2004, 23, 1416.
1
1 to 11.8 In the H NMR spectrum of 11, two doublet peaks
assignable to the olefinic protons of the coordinated stilbene
appeared at δ 3.66 and 3.38 ppm. The coupling constant of JHH

6332 Organometallics, Vol. 26, No. 25, 2007
Shima et al.
the range of those for the common agostic interaction. Therefore,
we concluded that there was no bonding interaction between
Ru1 and C8. The NMR data also supported this result.
The alkenyl ligand in 11, which is σ bonded to the osmium
and π bonded to the ruthenium, is probably formed via an initial
π coordination of the second diphenylacetylene molecule to the
osmium and subsequent cis-insertion of the carbon-carbon
triple bond into the osmium-hydride bond.
When 11 was heated in C6D6 at 50 °C for 31 h, perpendicu-
larly coordinated diphenylacetylene complex [Cp*Ru(µ-H)2(µ-
η2:η2-PhCCPh)OsCp*] (12) and benzoosmacyclopentadiene
complex [Cp*OsH2(µ-PhCdCH-C6H4-)RuCp*] (13) were
formed in 89% and 11% yields, respectively (eq 4). A GLC
analysis of the solution revealed the formation of trans- and
cis-stilbene in 92% and 8% yields, respectively.
Figure 2. ORTEP drawing of 11′, with thermal ellipsoids at the
30% probability level. Selected bond lengths (Å), angles, and torsion
angles (deg): Ru1-Os1, 2.8203(9); Os1-C7, 2.13(1); Os1-C8,
2.186(9); Os1-C21, 2.036(9); Ru1-C21, 2.31(1); Ru1-C22, 2.28-
(1); C7-C8, 1.45(2); C21-C22, 1.51(2); C7-Os1-C21, 91.2(4);
C8-Os1-C21, 93.7(4); Os1-C21-C22, 122.4(6); Os1-C21-
Ru1, 80.7(3); Ru1-C21-C22, 69.5(6); Ru1-C22-C21, 72.0(6);
C6-C7-C8-C9, -124(1); C20-C21-C22-C23, -4(2).
) 9.4 Hz corresponds to the trans coupling of the coordinated
olefin. On the other hand, a signal of a â-H of the η1:η2-alkenyl
ligand was observed at significant upfield (δ 2.75) due to the
π-coordination of the alkenyl ligand to the ruthenium center.
In the 13C NMR spectrum of 11, two vinylic carbons were
observed at δC 170.8 (s, vinyl CR) and 103.7 (d, JCH ) 141.7
Hz, vinyl Câ) ppm. These shifts are characteristic of µ-η1:η2-
vinyl ligands.9 The X-ray diffraction study established the
molecular structure of 11. An ORTEP drawing of [(C5Me4Et)-
Ru(µ-η1:η2-cis-PhCdCHPh)(µ-H)(trans-PhHCdCHPh)-
OsCp*] (11′) is illustrated in Figure 2 with selected bond
lengths, angles, and torsion angles. The ORTEP drawing clearly
shows that η1:η2-alkenyl ligand is σ bound to the osmium and
π bound to the ruthenium. In addition, the stereochemistry of
the alkenyl moiety is confirmed to be E-geometry. The resulting
structure of 11′ is fully consistent with the above-mentioned
spectral data. The Os1-C21 distance of 2.036(9) Å corresponds
to an Os-C σ bond, and the Ru1-C21 and Ru1-C22 bond
lengths of 2.31(1) and 2.28(1) Å, respectively, lie within the
range of those between Ru and π-bonded carbon atoms.10 The
Os1-C7 and Os1-C8 distances of 2.13(1) and 2.186(9) Å,
respectively, lie within the range of those between osmium and
π-bonded carbon atoms.11 The Ru1-C8 distance of 2.80 Å is
longer than that of the Ru1-C8 (2.56(1) Å) in 8′ and out of
This shows that the formation of 12 and 13 is accompanied
by the formation of trans- and cis-stilbene, respectively, as the
side products.
In the 1H NMR spectrum of 12, signals for the hydrides and
Cp* ligands were observed at δ -14.93, 1.56, and 1.84 ppm,
respectively, in an intensity ratio of 2:15:15. Characteristic
resonances for the perpendicularly coordinated bridging acety-
lenic carbons were observed to be equivalent at δ 88.5 ppm in
the 13C NMR spectrum, and the value was comparable to those
reported for [Co2(PhCCPh)(CO)6] (δ 89.2) and [Co2(PhCCPh)-
(CO)5(PBun )] (δ 89.6 and 91.7),12 but shifted more to an upper
3
field than that observed for 9 (δ 109.0).
X-ray diffraction study of 12 demonstrated the structure with
the perpendicularly bridged alkyne ligand. The ORTEP drawing
of 12 is shown in Figure 3 with selected bond lengths and angles.
The M-M* distance of 2.5433(7) Å corresponds to an Ru-Os
double bond and is consistent with the bond order between Ru
and Os atoms anticipated from the EAN rule applied to 12. The
C1-C1* distance of 1.323(6) Å is slightly longer than the
interatomic distance of the acetylenic carbons in 9 (1.315(8)
Å), but it is still within the range of those reported for the
perpendicularly coordinated alkynes, from 1.3 to 1.4 Å.13
Elongation of the C1-C1* distance in 12 would reflect the
enhanced back-donation from the metal centers to the alkyne
ligand.
(8) When we monitored the reaction by 1H NMR, the signal of complex
1 disappeared in the initial stage of the reaction and was never observed
during the reaction. Thus, the reaction path, which involves the reversion
of complex 8 to 1 before conversion to 11, was ruled out.
(9) (a) Colborn, R. E.; Dyke, A. F.; Gracey, B. P.; Knox, S. A. R.;
Macpherson, K. A.; Mead, K. A.; Orpen, A. G. J. Chem. Soc., Dalton Trans.
1990, 761. (b) Xue, Z.; Sieber, W. J.; Knobler, C. B.; Kaesz, H. D. J. Am.
Chem. Soc. 1990, 112, 1825. (c) Dyke, A. F.; Knox, S. A. R.; Morris, M.
J.; Naish, P. J. J. Chem. Soc., Dalton Trans. 1983, 1417. (d) Iggo, J. A.;
Mays, M. J.; Raithby, P. R.; Hendrick, K. J. Chem. Soc., Dalton Trans.
1983, 205.
(11) (a) Baratta, W.; Herdtweck, E.; Martinuzzi, P.; Rigo, P. Organo-
metallics 2001, 20, 305. (b) Hasegawa, T.; Sekine, M.; Schaefer, W. P.;
Taube, H. Inorg. Chem. 1991, 30, 449.
(12) Aime, S.; Milone, L.; Rossetti, R.; Stanghellini, P. L. Inorg. Chim.
Acta 1977, 22, 135.
(10) (a) Bott, S. G.; Shen, H.; Senter, R. A.; Richmond, M. G.
Organometallics 2003, 22, 1953. (b) Nombel, P.; Lugan, N.; Donnadieu,
B.; Lavigne, G. Organometallics 1999, 18, 187. (c) Cabeza, J. A.;
Llamazares, A.; Riera, V.; Briard, P.; Ouahab, L. J. Organomet. Chem.
1994, 480, 205.
(13) (a) Byrne, L. T.; Griffith, C. S.; Koutsantonis, G. A.; Skelton, B.
W.; White, A. H. J. Chem. Soc., Dalton Trans. 1998, 1575. (b) Pasynk-
iewicz, S.; Pietrzykowski, A.; Niemiec-Kryza, B.; Zachara, J. J. Organomet.
Chem. 1998, 566, 217. (c) Colborn, R. E.; Dyke, A. F.; Knox, S. A. R.;
Macpherson, K. A.; Orpen, A. G. J. Organomet. Chem. 1982, 239, C15.

Reaction of a Polyhydrido Cluster with Diphenylacetylene
Organometallics, Vol. 26, No. 25, 2007 6333
to Câ), and the signal of Câ appeared at δ 92.9 ppm (d, JCH
)
157.8 Hz) in the 13C NMR spectrum. These spectral data are
comparable to those of [Cp*Ir(µ-H)(µ-PhCdCH-C6H4-)-
RuCp*] (14)14 and [Cp*OsH2(µ-PhCdCH-C6H4-)OsCp*] (15)
(vide infra). It is noteworthy that complex 13 is also formed in
78% yield upon pyrolysis of 8 at 80 °C in THF for 21 h, even
in the absence of added diphenylacetylene. Liberation of
dihydrogen in the pyrolysis of 8 was evidenced by the detection
of bibenzyl by GLC analysis when the reaction was carried
out in the presence of a mixture of cis- and trans-stilbene. Upon
heating, 8 was probably isomerized to E (Scheme 3), which
liberated dihydrogen and would undergo olefinic C-H
bond activation and orthometallation at the osmium center to
generate 13.
The structure of [Cp*OsH2(µ-PhCdCH-C6H4-)Ru(C5Me4-
Et)] (13′) was determined by X-ray study. The ORTEP drawing
is shown in Figure 4 with selected bond lengths and angles.
The Cp* and the C5Me4Et ligands mutually occupied trans
positions with respect to the Ru-Os bond. Os1-C7 and Os1-
C10 bond lengths of 2.107(5) and 2.085(6) Å, respectively,
correspond to an Os-C σ bond. Interatomic distances between
Ru1 and C7, C8, C9, and C10 ranged from 2.150(5) to 2.238-
(6) Å and lie within the range of those between Ru and π-bonded
carbon atoms.
Figure 3. ORTEP drawing of 12 (M ) Os (50%) and Ru (50%)),
with thermal ellipsoids at the 30% probability level. Selected bond
lengths (Å) and angles (deg): M-M*, 2.5433(7); M-C1, 2.159-
(3); C1-C1*, 1.323(6); M-C1-M*, 72.20(9); C2-C1-C1*, 141.6
(2).
Reaction of Diosmium Tetrahydride Complex with Diphe-
nylacetylene. To compare the reactivity of a series of dinuclear
tetrahydrido complexes, we also examined the reaction of the
diosmium tetrahydride, [Cp*Os(µ-H)4OsCp*] (7),15 with diphe-
nylacetylene.
Complex 7 is less reactive toward diphenylacetylene than 6
and 1, and 7 was recovered almost quantitatively when the
reaction of 7 with equimolar amount of diphenylacetylene was
conducted in benzene at 50 °C.
When 7 was treated with 2.0 equiv of diphenylacetylene in
THF at 100 °C for 22 h, osmacyclopentadiene complex
[Cp*OsH2(µ-PhCdCH-C6H4-)OsCp*] (15) was formed to-
gether with trans-stilbene, cis-stilbene, and bibenzyl. The
organic byproducts were detected by GLC (eq 5). In contrast
to the reaction of 1, no intermediary species was detected when
the reaction was monitored by means of 1H NMR spectroscopy.
Figure 4. ORTEP drawing of 13′, with thermal ellipsoids at the
30% probability level. The second molecule in the unit cell has
been omitted for clarity. Selected bond lengths (Å) and angles
(deg): Ru1-Os1, 2.7564(5); Os1-C7, 2.107(5); Os1-C10, 2.085-
(6); Ru1-C7, 2.150(5); Ru1-C8, 2.185(5); Ru1-C9, 2.238(6);
Ru1-C10, 2.183(6); Os1-C7-Ru1, 80.7(2); Os1-C10-Ru1,
80.4(2); Os1-C7-C8, 113.9(4); C7-C8-C9, 116.4(5); C8-C9-
C10, 113.3(5); Os1-C10-C9, 114.6(4).
Complex 12 was formed as a result of liberation of the η2-
trans-stilbene from 11 and subsequent â-H elimination from
the cis-alkenyl ligand. This mechanism is likely applicable to
the formation of the ruthenium analogue 9 in the reaction of 6
with diphenylacetylene. Formation of the minor product 13
implies the intermediacy of the (Z)-R-phenyl-R-styrylosmium
species K, which is equilibrated with 11 via a bis(stilbene)
species J. Liberation of cis-stilbene from K would generate G.
Intermediate G would undergo orthometallation to form 13
(Scheme 4).
The structure of 15 is closely analogous to that of 13. In the
1H NMR spectrum of 15, two hydride signals were observed
as doublets at δ -13.72 (J ) 7.2 Hz) and -14.25 ppm (J )
7.2 Hz), and these chemical shifts were quite comparable to
those for hydrides in 13 (δ -13.73 and -14.31 ppm). The
resonance signal of the C2 in 15, which is π-bonded to the
osmium, shifts upfield, δ 83.9 ppm, as compared to that of the
corresponding carbon in 13, δ 92.9 ppm. As mentioned above,
a similar trend was observed for the 13C signal of the complexes
2 and 3.1,2 The molecular structure of 15 was very similar to
that of 13.16 The two Cp* ligands mutually occupied the trans
The side-product 13 formed in the thermolysis of 11 was
identified by 1H, 13C NMR and IR spectroscopy. In the 1H NMR
spectrum of 13, signals of the hydrido ligands appeared as a
doublet at δ -13.73 and -14.31 ppm with coupling constant J
) 7.2 Hz. In the IR spectrum, absorption of the metal-hydride
(14) Shima, T.; Suzuki, H. Organometallics 2000, 19, 2420.
(15) Gross, C. L.; Wilson, S. R.; Girolami, G. S. J. Am. Chem. Soc.
1994, 116, 10294.
1
stretching vibration appeared at 2102 and 2072 cm-1. The H
signals of the osmacycle were observed at δ 5.94 ppm (H bound
(16) See the Supporting Information for the structural data of 15.

6334 Organometallics, Vol. 26, No. 25, 2007
Shima et al.
Scheme 4. Formation of Complex 13
Scheme 5. Plausible Paths for the Reaction of the Dinuclear Tetrahydrido Complexes 1, 6, and 7 with Diphenylacetylene
positions with respect to the Os-Os vector. All of the structural
parameters within 15 appear normal.
which afforded an intermediate B, followed by reductive
coupling between the M′-H and the M′-C would also be
possible. There have been several precedents of µ-perpendicular
coordination of alkyne to the dinuclear transition metal com-
plexes. For example, Muetterties et al. proposed the initial
µ-perpendicular coordination of alkyne for the reaction of the
dinuclear rhodium complex [(P(O-i-C3H7)3)2Rh(µ-H)]2 with
diphenylacetylene.17 Insertion of the cis-stilbene ligand into the
M-H bond, subsequent rotation around the C-C single bond
of the resulting alkyl group, followed by â-hydrogen elimination
then afford an intermediary η2-trans-stilbene complex E.
Mechanistic Aspects of the Reaction of 1 with Dipheny-
lacetylene. On the basis of these observations, we propose a
mechanism illustrated in Scheme 5 for the reaction of the
dinuclear tetrahydrido complexes 1, 6, and 7 with dipheny-
lacetylene. The mechanism of the formation of 10 involves
initial alkyne insertion into one of the M-H bond yielding a
vinyl intermediate A and subsequent reductive coupling between
the M-H and the M-C. However, the initial coordination of
diphenylacetylene to complex 1 in the µ-perpendicular fashion,

Reaction of a Polyhydrido Cluster with Diphenylacetylene
Organometallics, Vol. 26, No. 25, 2007 6335
spectra were recorded on Varian INOVA-400 Fourier transform
spectrometers with tetramethylsilane as an internal standard.
Elemental analyses were performed by a Perkin-Elmer 2400II.
[Cp*Ru(µ-H)4OsCp*] (1),1 [Cp*Ru(µ-H)4RuCp*] (6),2 and [Cp*Os-
(µ-H)4OsCp*] (7)15 were prepared according to a previously
published method.
Complex E would be in equilibrium with complex 8 in solution,
which was isolated in the reaction of 1. The equilibrium between
8 and E is surely the turning point of the reaction. As mentioned
above, complex 8 reacted with added diphenylacetylene to lead
to the formation of 11, which underwent liberation of the η2-
trans-stilbene ligand and C-H oxidative addition at the â-carbon
of the (E)-σ,π-alkenyl group to yield 12. Liberation of cis-
stilbene from 11 generates an intermediary trans-stilbene
complex F, which is converted into 13 via a cyclometallation
subsequent to an oxidative addition of the olefinic C-H bond
of the stilbene ligand at the osmium site. In contrast, pyrolysis
of 8 in the absence of diphenylacetylene also results in the
formation of 13, probably via F formed as a result of liberation
of dihydrogen from E.
The Os-Os complex 7 reacts with 2 equiv of diphenylacety-
lene to give 15, exclusively, together with trans-stilbene, cis-
stilbene, and bibenzyl. This reaction occurs via the intermediate
complexes, E and F. However, in the dehydrogenation step from
E to F, excess diphenylacetylene serves as a hydrogen acceptor
to form trans-stilbene, cis-stilbene, and bibenzyl.
[Cp*Ru(µ-H)2(µ-trans-PhHCdCHPh)OsCp*] (8). A 50 mL
Schlenk tube was charged with 35.8 mg (0.0633 mmol) of 1 and 5
mL of toluene. Diphenylacetylene (14.1 mg, 0.0791 mmol) was
added, and the reaction mixture was stirred at room temperature
for 4 h. The color of the solution turned from red-brown to brown.
Removal of the solvent under reduced pressure followed by washing
of the residual solid with methanol gave 41.5 mg (0.0558 mmol,
1
88%) of 8 as a brown solid. H NMR (C6D6, rt): 7.76 (d, JHH
)
7.8 Hz, 2H, o-Ph), 7.68 (d, JHH ) 7.8 Hz, 2H, o-Ph), 7.27 (t, JHH
) 7.6 Hz, 2H, m-Ph), 7.19 (t, JHH ) 8.0 Hz, 2H, m-Ph), 7.08 (t,
JHH ) 7.8 Hz, 1H, p-Ph), 6.99 (t, JHH ) 7.2 Hz, 1H, p-Ph), 5.51
(d, JHH ) 6.8 Hz, 1H, PhCHdCHPh), 4.53 (d, JHH ) 6.8 Hz, 1H,
PhCHdCHPh), 1.76 (s, 15H, Cp*), 1.67 (s, 15H, Cp*), -15.25
(d, JHH ) 3.8 Hz, 1H, µ-H), -17.67 (d, JHH ) 3.8 Hz, 1H, µ-H).
13C NMR (C6D6, rt): 151.5 (s, Ph), 151.0 (s, Ph), 130.3 (d, JCH
)
Previously, we reported that the Ru-Ir complex [Cp*Ru(µ-
H)3IrCp*] (16) reacted with diphenylacetylene to form an
iridacyclopentadiene complex [Cp*IrH(µ-PhCdCH-C6H4-)-
RuCp*] (14) by way of a trans-σ,π-alkenyl complex [Cp*Ir-
(µ-H)2(µ-σ,π-(Z)-PhCdCHPh)RuCp*] (17).14 Complexes 14
and 17 offer structurally close analogies to an intermediate G
and 13, respectively. Therefore, the formation mechanism of
13, which involves the orthometallation at the osmium site of
G, appears reasonable, although the formation of G was not
confirmed spectroscopically.
154.1 Hz, Ph), 127.6 (dd, JCH ) 5.4 Hz, obscured by C6D6, Ph),
124.0 (d, JCH ) 160.9 Hz, Ph), 123.2 (d, JCH ) 154.6 Hz, Ph),
87.4 (s, C5Me5), 76.7 (s, C5Me5), 39.2 (d, JCH ) 147.8 Hz, PhCHd
CHPh), 20.1 (d, JCH ) 132.4 Hz, PhCHdCHPh), 12.7 (q, JCH
)
125.7 Hz, C5Me5), 11.3 (q, JCH ) 126.1 Hz, C5Me5). HH COSY
(rt): δ 5.51-4.53, δ 7.76-7.27, δ 7.68-7.19. CH HMQC (rt):
δC 39.2 - δH 4.53, δC 20.1 - δH 5.51, δC 130.3 - δH 7.68, δC
124.0 - δH 7.08, δC 123.2 - δH 6.99. Anal. Calcd for C34H44-
RuOs: C, 54.89; H, 5.92. Found: C, 54.58; H, 5.92. IR (cm-1):
3055, 3025, 2974, 2903, 1595, 1490, 1452, 1378, 1029, 693, 650,
634.
[Cp*Ru(µ-H)2(µ-cis-PhHCdCHPh)OsCp*] (10). A 5-mm
NMR tube was charged with 9.7 mg (0.0172 mmol) of 1 and 0.4
mL of toluene-d8. Diphenylacetylene (30.6 mg, 0.172 mmol) was
added, and the reaction mixture was kept at -5 °C for 1 h. The
signal for 1 disappeared, and the formation of complex 10 in a ca.
89% NMR yield was observed. Complex 10 could not be isolated
Conclusion
The combination of the metals is likely reflected in the
reactivity of the heterometallic cluster complex, but there have
been, thus far, few systematic studies on their reactivity. Here,
the study focused on the reaction of binuclear polyhydrido
complexes 1, 6, and 7, containing group 8 metals, with
diphenylacetylene.
because of its thermolability and was characterized by 1H and 13
C
NMR spectroscopy. 1H NMR (toluene-d8, -5 °C): 7.81 (d, JHH
)
8.0 Hz, 2H, o-Ph), 7.20 (d, JHH ) 8.0 Hz, 2H, m-Ph), 7.04 (obscured
by toluene, p-Ph), 3.33 (s, 2H, cis-stilbene-H), 1.77 (s, 15H, C5Me5),
1.46 (s, 15H, C5Me5), -16.31 (s, 2H, µ-H). 13C NMR (toluene-d8,
-5 °C): 149.8 (s, ipso-Ph), 132.9 (d, JCH ) 157.4 Hz, Ph), 126.6
(d, JCH ) 156.0 Hz, Ph), 124.4 (d, obscured by toluene, Ph), 89.5
(s, C5Me5), 73.6 (s, C5Me5), 38.2 (d, JCH ) 146.9 Hz, Ph-CHd
CH-Ph), 12.0 (q, JCH ) 125.6 Hz, C5Me5), 11.5 (q, JCH ) 126.5
Hz, C5Me5).
We previously reported that 6 reacted with dipenylacetylene
to yield 9, exclusively. In contrast, 7 selectively affords 15 in
reaction with diphenylacetylene. The reaction mode of 1 was
intermediate between the homodinuclear complexes 6 and 7,
and the reaction of 1 with an excess amount of diphenyacetylene
at 50 °C resulted in the formation of 12 and 13 by way of
intermediary complexes 10 and 8. It is noteworthy that a metal-
carbon σ-bond was exclusively formed at the osmium center.
This result most likely reflects the thermodynamic preference
of the carbon-metal bond formation at the osmium center and
that the ruthenium atom plays the role of a binding site.
[Cp*Ru(µ-H)(µ-σ, π-trans-CPhdCHPh)(trans-PhHCdCHPh)-
OsCp*] (11). A 50 mL Schlenk tube was charged with 76.6 mg
(0.135 mmol) of 1 and 2 mL of toluene. Diphenylacetylene (196.7
mg, 1.10 mmol) was added, and the reaction mixture was stirred
at room temperature for 8 h. The color of the solution turned from
red-brown to black. Removal of the solvent under reduced pressure
followed by the crystallization with THF/MeOH gave 85.5 mg
(0.0927 mmol, 69%) of complex 11 as a black crystalline solid.
1H NMR (C6D6, rt): 7.69 (d, JHH ) 7.2 Hz, 2H, Ph), 7.49 (d, JHH
) 7.6 Hz, 2H, Ph), 6.87-7.23 (m, 12H, Ph), 6.68 (d, JHH ) 7.2
Hz, 1H, Ph), 6.42 (d, JHH ) 8.0 Hz, 2H, Ph), 5.81 (d, JHH ) 8.0
Hz, 1H, Ph), 3.66 (d, JHH ) 9.4 Hz, 1H, PhCHdCHPh), 2.75 (s,
1H, OsPhCdCHPh), 2.28 (d, JHH ) 9.4 Hz, 1H, PhCHdCHPh),
1.42 (s, 15H, C5Me5), 1.39 (s, 15H, C5Me5), -5.78 (s, 1H, µ-H).
13C NMR (C6D6, rt): 170.8 (s, OsPhCdCHPh), 161.4 (s, ipso-
Ph), 147.2 (s, ipso-Ph), 145.6 (s, ipso-Ph), 144.8 (s, ipso-Ph),
123.3-132.5 (Ph), 103.7 (d, JCH ) 141.7 Hz, OsCdCHPh), 93.8
(s, C5Me5), 78.7 (s, C5Me5), 33.9 (d, JCH ) 146.5 Hz, PhCHd
Experimental Section
General Procedures. All manipulations were carried out under
an argon atmosphere with use of standard Schlenk techniques.
Toluene and THF were distilled from sodium benzophenone ketyl
prior to use. Pentane was dried over P2O5 and distilled prior to
use. Methanol was dried over Mg(OMe)2 and distilled prior to use.
Diphenylacetylene and other substrates were purchased from
commercial sources and used without further purification. IR spectra
1
were recorded on a Nicolet Avatar 360 FT-IR. H and 13C NMR
(17) (a) Burch, R. R.; Shusterman, A. J.; Muetterties, E. L.; Teller, R.
G.; Williams, J. M. J. Am. Chem. Soc. 1983, 105, 3546. (b) Burch, R. R.;
Muetterties, E. L.; Teller, R. G.; Williams, J. M. J. Am. Chem. Soc. 1982,
104, 4257.
CHPh), 22.3 (d, JCH ) 144.4 Hz, PhCHdCHPh), 11.4 (q, JCH
)

6336 Organometallics, Vol. 26, No. 25, 2007
Table 1. Crystallographic Data for 8′, 11′, 12, 13′, and 15
Shima et al.
8′
11′
12
13′
15
formula
formula weight
crystal system
space group
a, Å
C35H46OsRu
758.00
monoclinic
P21/n (No. 14)
9.094(1)
C49H56OsRu
936.21
triclinic
P1h (No. 2)
11.391(4)
17.621(5)
11.303(2)
98.789(9)
112.55(2)
76.79(2)
2034.5(9)
2
1.528
253(2)
3.523
60.0°
6667
C34H42OsRu
741.95
C35H44OsRu
755.97
C34H42Os2
831.08
triclinic
P1h (No. 2)
10.9901(4)
14.2683(9)
19.106(1)
98.777(2)
90.598(1)
95.414(4)
2946.8(3)
4
1.873
253(2)
8.635
55.0°
12 073
12 073
9785
0.0453
0.1003
677
monoclinic
C2/c (No. 15)
11.6039(5)
16.8688(7)
15.809(1)
triclinic
P1h (No. 2)
14.3301(6)
11.0610(3)
19.2268(5)
90.338(1)
97.714(2)
95.387(1)
3006.1(2)
4
1.670
233(2)
4.746
55.0°
20 999
12 804
10 724
0.0381
b, Å
c, Å
17.826(2)
19.789(2)
R, deg
â, deg
94.333(4)
104.885(3)
γ, deg
V, Å3
3198.9(6)
4
2990.6(3)
4
Z
D
calcd, g/cm3
1.574
233(2)
4.460
55.0°
12 441
7217
1.648
233(2)
4.769
55.0°
3438
3438
3048
0.0324
0.0757
173
temp, K
µ, mm-1 (Mo KR)
2θmax
reflns collected
ind data
ind data (I > 2σ(I))
R1
wR2
parameters
GOF
6667
5797
0.0647
0.1331
485
5554
0.0789
0.1876
291
0.0800
711
1.075
1.142
1.068
1.133
1.172
125.9 Hz, C5Me5), 10.3 (q, JCH ) 126.1 Hz, C5Me5). Anal. Calcd
for C48H54RuOs: C, 62.52; H, 5.86. Found: C, 62.38; H, 6.0. IR
(cm-1): 3052, 2978, 2902, 1592, 1487, 1070, 1027, 756, 696.
[Cp*Ru(µ-H)2(µ-η2:η2-PhCCPh)OsCp*] (12). A 5-mm NMR
tube was charged with 22.4 mg (0.0243 mmol) of 11 and 0.4 mL
of C6D6. The solution was kept at 50 °C for 31 h, during which
time the color changed from black to brown. 1H NMR spectroscopy
revealed the formation of 12 (89%) and 13 (11%). The GC analysis
of the liquid phase of the reaction revealed the formation of ca.
92% of trans-stilbene and 8% of cis-stilbene. Crystallization from
THF/MeOH afforded 12 (12.9 mg, 0.0174 mmol, 72%) as a brown
crystalline solid. 1H NMR (C6D6, rt): 7.80 (dd, JHH ) 7.8, 1.6 Hz,
4H, Ph), 7.23 (t, JHH ) 7.8 Hz, 4H, Ph), 7.15 (m, 2H, Ph), 1.84 (s,
15H, C5Me5), 1.56 (s, 15H, C5Me5), -14.93 (s, 2H, µ-H). 13C NMR
(C6D6, rt): 142.2 (s, ipso-Ph), 129.1 (d, obscured by C6D6, Ph),
128.6 (d, obscured by C6D6, Ph), 124.2 (d, JCH ) 159.3 Hz, Ph),
55.15; H, 5.66. IR (cm-1): 3059, 3011, 2964, 2901, 2102 (νOsH),
2072 (νOsH), 1593, 1487, 1376, 1262, 1029, 759.
[Cp*OsH2(µ-PhCdCH-C6H4-)OsCp*] (15). A 50 mL Schlenk
tube was charged with 47.7 mg (0.0729 mmol) of 7 and 5 mL of
THF. Diphenylacetylene (26.1 mg, 0.146 mmol) was added, and
the reaction mixture was refluxed for 22 h. The color of the solution
changed slightly from red-brown to bright brown. The solvent was
removed under reduced pressure, and the residue was purified by
column chromatography on alumina. The orange band that was
eluted with toluene/pentane (1/5) was combined, the solvent was
removed, and the residue was recrystallized from THF/MeOH to
1
give red crystals (32.7 mg, 0.0394 mmol, 54%) of 15. H NMR
(C6D6, rt): 7.85 (m, 3H, Ph), 7.35 (d, JHH ) 7.6 Hz, 1H, Ph), 7.28
(d, JHH ) 7.6 Hz, 2H, Ph), 7.13 (t, JHH ) 7.6 Hz, 1H, Ph), 6.87
(m, 1H, Ph), 6.65 (m, 1H, Ph), 6.41 (s, 1H, â-H), 1.64 (s, 15H,
Cp*), 1.55 (s, 15H, Cp*), -13.72 (d, JHH ) 7.2 Hz, 1H, µ-H),
-14.25 (d, JHH ) 7.2 Hz, 1H, µ-H). 13C NMR (C6D6, rt): 153.9
(d, JCH ) 150.7 Hz, Ph), 152.8 (s, R-C), 127.9 (obscured by C6D6,
Ph), 127.1 (obscured by C6D6, Ph), 125.6 (obscured by C6D6, Ph),
123.7 (d, JCH ) 158.5 Hz, Ph), 117.5 (s, â-C or Ph), 115.8 (d, JCH
) 154.7 Hz, Ph), 113.6 (s, â-C or Ph), 111.6 (s, â-C or Ph), 91.8
(s, C5Me5), 83.9 (d, JCH ) 160.8 Hz, â-C), 81.6 (s, C5Me5), 10.5
(q, JCH ) 125.6 Hz, C5Me5), 10.4 (q, JCH ) 126.6 Hz, C5Me5).
Anal. Calcd for C34H42Os2: C, 49.09; H, 5.05. Found: C, 49.09;
H, 5.00. IR (cm-1): 3054, 3009, 2962, 2900, 2094 (νOsH), 2058
(νOsH), 1593, 1376, 1070, 1031, 770.
X-ray Data Collection and Reduction. Crystals suitable for
X-ray analysis of 8′, 11′, 12, 13′, and 15 were obtained from THF/
MeOH solution at room temperature. The crystals were mounted
on glass fibers. The data were collected on a Rigaku RAXIS-CS
imaging plate area detector and RAXIS-RAPID imaging plate area
detector equipped with graphite-monochromated Mo KR radiation
(λ ) 0.71069 Å) in the 5° < 2θ < 60° range. The data were
processed using the TEXSAN crystal structure analysis package18
operated on an IRIS Indigo computer. Atomic scattering factors
were obtained from the standard sources. In the reduction of the
data, Lorentz/polarization corrections and empirical absorption
corrections based on azimuthal scans were applied to the data for
each structure.
88.9 (s, C5Me5), 88.5 (s PhCCPh), 87.8 (s, C5Me5), 12.4 (q, JCH
)
125.9 Hz, C5Me5), 11.8 (q, JCH ) 125.9 Hz, C5Me5). Anal. Calcd
for C34H42RuOs: C, 55.04; H, 5.67; Found C, 54.93; H, 5.68. IR
(cm-1): 2971, 2902, 1669, 1590, 1485, 1443, 1377, 1069, 1029,
762, 695.
[Cp*OsH2(µ-PhCdCH-C6H4-)RuCp*] (13). A 50 mL Schlenk
tube was charged with 154.9 mg (0.208 mmol) of 8 and 5 mL of
THF. The reaction mixture was refluxed for 21 h. The color of the
solution turned from brown to red-brown. The solution was
evaporated to dryness, and the residue was purified by column
chromatography on alumina. The orange band that was eluted with
toluene/pentane (1/5) afforded 119.9 mg (0.162 mmol, 78%) of
1
13. H NMR (C6D6, rt): 7.93 (d, JHH ) 7.2 Hz, 1H, -C6H4-),
7.90 (m, 2H, o-Ph), 7.41 (d, JHH ) 7.2 Hz, 1H, -C6H4-), 7.30 (t,
JHH ) 7.2 Hz, 2H, m-Ph), 7.14 (t, JHH ) 7.2 Hz, 1H, p-Ph),
6.99 (t, JHH ) 7.2 Hz, 1H, -C6H4-), 6.72 (t, JHH ) 7.2 Hz, 1H,
-C6H4-), 5.94 (s, 1H, â-H), 1.56 (s, 15H, Cp*), 1.50 (s, 15H,
Cp*), -13.73 (d, JHH ) 7.2 Hz, 1H, µ-H), -14.31 (d, JHH ) 7.2
Hz, 1H, µ-H). 13C NMR (C6D6, rt): 152.2 (d, JCH ) 157.0 Hz,
Ph), 151.9 (s, R-C), 137.3 (s, R-C), 130.4 (br, o-Ph), 127.7 (obscured
by C6D6, m-Ph), 126.5 (d, JCH ) 156.2 Hz, Ph), 125.5 (d, JCH
155.4 Hz, Ph), 124.6 (d, JCH ) 159.2 Hz, p-Ph), 117.4 (d, JCH
)
)
154.7 Hz, Ph), 117.0 (s, â-C), 92.9 (d, JCH ) 157.8 Hz, â-C), 92.5
(s, C5Me5), 84.8 (s, C5Me5), 10.25 (q, JCH ) 126.6 Hz, C5Me5),
10.22 (q, JCH ) 125.6 Hz, C5Me5). HH COSY (rt): δ 7.90-7.30,
δ 7.41-6.99, δ 7.30-7.14, δ 6.99-6.72, δ 6.72-7.93. CH HMQC
(rt): δC 130.4 - δH 7.90, δC 127.7 - δH 7.30, δC 124.6 - δH
7.14, δC 126.5 - δH 7.41, δC 125.5 - δH 6.99, δC 117.4 - δH
6.72. Anal. Calcd for C34H42RuOs: C, 54.99; H, 5.66. Found: C,
Structure Solutions and Refinement. The structures were
solved by the Patterson method (DIRDIF9419 PATTY20) and
expanded using Fourier techniques. The non-hydrogen atoms were
(18) TEXSAN, Crystal Structure Analysis Package; Molecular Structure
Corp.: The Woodlands, TX, 1985 and 1992.

Reaction of a Polyhydrido Cluster with Diphenylacetylene
Organometallics, Vol. 26, No. 25, 2007 6337
refined on full-matrix least-squares on F2 using the SHELXL-97
program systems.21 For 8′, disorder at the C5Me4Et ligand that
bonded to the Ru1 was refined at the ratio of 47:53. The dinuclear
structure of 12 is disordered between two orientations (50 and 50%
occupancy). The hydrogen atoms, except those bonded to metals,
were located at the calculation positions and refined by using a
riding model. The metal-bound hydrogen atoms of 8′ and 11′ were
located in difference Fourier maps and refined with restraint. The
metal-bound hydrogen atoms of 12, 13′, and 15 (except those
bonded to the Os1 atom in 15) were located in the difference Fourier
maps and refined isotropically. Crystal data and results of the
analyses are listed in Table 1.
Acknowledgment. The present research is supported by the
Ministry of Education, Culture, Sports, Science, and Technol-
ogy, Japan, by grant no. 18064007 (Priority Area “Synergy of
Elements”) and from the Japan Society of the Promotion of
Science by grant no. 18105002 [Scientific Research (S)]. We
are also grateful to Kanto Chemical Co., Inc., for a generous
supply of pentamethylcyclopentadiene.
Supporting Information Available: Tables of atomic coordi-
nates and thermal parameters, bond lengths and angles, torsion
angles, and structure refinement details, and ORTEP drawings of
8′, 11′, 12, 13′, and 15 with full numbering scheme; crystallographic
data are also available in CIF format. This material is available
free of charge via the Internet at http://pubs.acs.org.
(19) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.; de
Gelder, R.; Israel, R.; Smits, J. M. M. DIRDIF94; University of Nijmegen:
The Netherlands, 1994.
(20) Beurskens, P. T.; Admiraal, G.; Beurskens, G.; Bosman, W. P.;
Garcia-Granda, S.; Gould, R. O.; Smits, J. M. M.; Smykalla, C. PATTY;
University of Nijmegen: The Netherlands, 1992.
(21) Scheldrick, G. M. SHELXL-97, Program for Crystal Structure
Solution; University of Goettingen: Germany, 1997.
OM700606Q