Synthesis and reactivity of labile MeCN adducts of diruthenium bis(μ-methylene) species, Cp2Ru2(μ-CH2)2(CO) n(MeCN)2-n (n = 1, 2): Reaction with H sources, H-X (X = SiR3, SnR3, H), and C-C coupling with alkynes and diazoalkanes

Article abstract of DOI:10.1021/om9706727

Irradiation of the diruthenium bis(μ-methylene) complex Cp₂Ru₂(μ-CH₂)₂(CO)₂ (1), in acetonitrile gives the mono- and bis(acetonitrile) species Cp₂Ru₂(μ-CH₂)₂(CO)(MeCN) (2) and Cp₂Ru₂(μ-CH₂)₂(MeCN)₂ (3) in a successive manner. The mono-MeCN species 2 has been characterized spectroscopically and crystallographically, but the bis-MeCN species 3 is too unstable to be fully characterized. Reaction of 2 with hydrosilanes and hydrostannanes results in oxidative addition of the H-Si and H-Sn bond to give hydrido-μ-methylene complexes, Cp₂Ru₂(μ-CH₂)₂(H)(mR ₃)(CO) (m = Si (7), Sn (9)). In the case of the reactions with dihydrosilane, phenylsilane, and triphenylstannane, one of the two methylene bridges is eliminated as methane (and benzene from phenylsilane) to give μ-methylene-μ-silylene complexes, Cp₂Ru₂(μ-CH₂)(μ-SiR ₂)(H)(SiR₃)(CO) (8), and a tristannyl-μ-methylene complex, Cp₂Ru₂(μ-CH₂)(μ-H)(SnPh₃) ₃(CO) (10). Treatment of 2 with alkynes (R¹C≡CR²) and diphenyldiazomethane produces the metallacyclic products Cp₂Ru₂[μ-η³-C(R¹)C(R ²)=CH₂](μ-CH₂)(CO) (12), and the vinylidene complex Cp₂Ru₂(μ-C=CPh₂)(μ-η ³-CPh₂) (14), respectively, via C-C coupling. In contrast to 2, corresponding reactions of the bis-MeCN species 3 are sluggish and only the simple MeCN replacement reaction proceeds in a selective manner.

Full text of DOI:10.1021/om9706727

5572
Organometallics 1997, 16, 5572-5584
Syn th esis a n d Rea ctivity of La bile MeCN Ad d u cts of
Dir u th en iu m Bis(µ-m eth ylen e) Sp ecies,
Cp 2Ru 2(µ-CH2)2(CO)n (MeCN)2-n (n ) 1, 2): Rea ction w ith
H Sou r ces, H-X (X ) SiR3, Sn R3, H), a n d C-C Cou p lin g
w ith Alk yn es a n d Dia zoa lk a n es
Munetaka Akita,* Ruimao Hua, Sadahiro Nakanishi, Masako Tanaka, and
Yoshihiko Moro-oka*
Research Laboratory of Resources Utilization, Tokyo Institute of Technology, 4259 Nagatsuta,
Midori-ku, Yokohama 226, J apan
Received August 4, 1997X
Irradiation of the diruthenium bis(µ-methylene) complex Cp2Ru2(µ-CH2)2(CO)2 (1), in
acetonitrile gives the mono- and bis(acetonitrile) species Cp2Ru2(µ-CH2)2(CO)(MeCN) (2) and
Cp2Ru2(µ-CH2)2(MeCN)2 (3) in a successive manner. The mono-MeCN species 2 has been
characterized spectroscopically and crystallographically, but the bis-MeCN species 3 is too
unstable to be fully characterized. Reaction of 2 with hydrosilanes and hydrostannanes
results in oxidative addition of the H-Si and H-Sn bond to give hydrido-µ-methylene
complexes, Cp2Ru2(µ-CH2)2(H)(mR3)(CO) (m ) Si (7), Sn (9)). In the case of the reactions
with dihydrosilane, phenylsilane, and triphenylstannane, one of the two methylene bridges
is eliminated as methane (and benzene from phenylsilane) to give µ-methylene-µ-silylene
complexes, Cp2Ru2(µ-CH2)(µ-SiR2)(H)(SiR3)(CO) (8), and a tristannyl-µ-methylene complex,
Cp2Ru2(µ-CH2)(µ-H)(SnPh3)3(CO) (10). Treatment of 2 with alkynes (R1CtCR2) and diphen-
yldiazomethane produces the metallacyclic products Cp2Ru2[µ-η3-C(R1)C(R2)dCH2](µ-
CH2)(CO) (12), and the vinylidene complex Cp2Ru2(µ-CdCPh2)(µ-η3-CPh2) (14), respectively,
via C-C coupling. In contrast to 2, corresponding reactions of the bis-MeCN species 3 are
sluggish and only the simple MeCN replacement reaction proceeds in a selective manner.
Sch em e 1
In tr od u ction
A polynuclear complex containing more than two
bridging alkylidene units is one of the attractive can-
didates which may be able to reproduce the multiple
C-C coupling process occurring on a heterogeneous
catalyst surface (Scheme 1).1 However, only a few
reports have appeared so far, mainly because examples
of polynuclear poly(alkylidene) complexes are limited.
Maitlis and his co-workers reported that a successful
C-C coupling was observed upon thermolysis or oxida-
tion of a bis(µ-methylene)dimethyldirhodium complex,
Cp*2Rh2(µ-CH2)2(CH3)2, where coupling of the two CH2
units and one methyl group led to the formation of a C3
product, propene.2 In contrast to the case for the
rhodium system, it was reported that C-C coupling of
bis(µ-alkylidene)diruthenium complexes, Cp2Ru2(µ-CR2)2-
(CO)2, was sluggish under thermolysis conditions3 and
a low-yield mixture of products was merely obtained,
as reported by Knox et al. In a previous paper, we
reported the synthesis of the bis(µ-methylene) complex
Cp2Ru2(µ-CH2)2(CO)2 (1) via deoxygenative reduction of
a simple carbonyl complex, Cp2Ru2(CO)4, with hydro-
silane.4 However, its thermolysis also produced very
small amounts of methane and C2 hydrocarbons, al-
though complex 1 contained bridging alkylidene ligands
which did not bear a â-hydrogen atom.
In order to introduce a component which may induce
C-C coupling with a bridging alkylidene ligand, re-
placement of a CO ligand by a labile “lightly stabilizing”
ligand has been studied.5 In the case of the mono(µ-
methylene) diruthenium system Cp2Ru2(µ-CH2)(CO)3 (4)
(Scheme 2), conversion to the MeCN adduct Cp2Ru2(µ-
CH2)(CO)2(MeCN) (5)6 resulted in successful coupling
X Abstract published in Advance ACS Abstracts, November 15, 1997.
(1) Somorjai, G. A. Introduction to Surface Chemistry and Catalysis;
Wiley-Interscience: New York, 1994.
(2) (a) Saez, I. M.; Andrews, D. G.; Maitlis, P. M. Polyhedron 1988,
7, 827. (b) Maitlis, P. M. J . Organomet. Chem. 1995, 500, 239. (c)
Maitlis, P. M.; Long, H. C.; Quyoum, R.; Turner, M. L.; Wang, Z.-Q. J .
Chem. Soc., Chem. Commun. 1996, 1.
(4) (a) Akita, M.; Oku, T.; Moro-oka, Y. J . Chem. Soc., Chem.
Commun. 1992, 1031. (b) Akita, M.; Hua, R.; Oku, T.; Moro-oka, Y.
Organometallics 1996, 15, 2548.
(5) Tachikawa, M.; Shapley, J . R. J . Organomet. Chem. 1977, 124,
C19.
(3) Colborn, R. E.; Davies, D. L.; Dyke, A. F.; Knox, S. A. R.; Mead,
K. A.; Orpen, A. G. J . Chem. Soc., Dalton Trans. 1989, 1799.
(6) Doherty, N. M.; Howard, J . A. K.; Knox, S. A. R.; Terril, N. J .;
Yates, M. I. J . Chem. Soc., Chem. Commun. 1989, 638.
S0276-7333(97)00672-9 CCC: $14.00 © 1997 American Chemical Society

MeCN Adducts of Ru2 Bis(µ-methylene) Species
Organometallics, Vol. 16, No. 25, 1997 5573
Sch em e 2
F igu r e 1. Molecular structure of 2 drawn at the 30%
probability level.
Ta ble 1. Selected Str u ctu r a l P a r a m eter s for 2a
Bond Lengths
with external, unsaturated hydrocarbons7 and we re-
cently reported C-C coupling of 5 with diazoalkane.8
In the latter system, olefinic products, including the
µ-alkenyl complexes Cp2Ru2(µ-CHdCR2)(µ-H)(CO)2, were
obtained via efficient coupling between the methylene
unit in 5 and the external alkylidene unit. In addition,
the methylene ligand in 4 and 5 was found to be
converted to methane upon treatment with hydrosilane,
and the formation mechanism of methane was success-
fully analyzed by using 5.9
As an extension of these studies, we report herein
synthesis of the labile MeCN adduct of the bis(µ-
methylene) complex 1, Cp2Ru2(µ-CH2)2(CO)(MeCN) (2),
and its reactivity toward various substrates (Scheme 2).
Complex 2 has been subjected to reactions with H
sources (HSiR3, HSnR3, and H2) as a comparative study
of our previous experiments of 5 mentioned above.
Reactions with alkyne and diazoalkane have also been
examined, but the expected multiple C-C coupling
among the two methylene bridges and an external
substrate has not been observed, as will be discussed
below. The synthesis and reactivity of the bis(aceto-
nitrile) species Cp2Ru2(µ-CH2)2(MeCN)2 (3) will also be
described.
Ru1-Ru2
Ru1-C1
Ru2-C1
Ru1-C2
Ru2-C2
2.6682(9)
2.083(5)
2.032(5)
2.078(5)
2.045(5)
Ru1-C3
Ru2-N1
C3-O1
C14-N1
C14-C15
1.811(5)
2.025(4)
1.160(5)
1.127(5)
1.460(7)
Bond Angles
Ru2-Ru1-C1
Ru2-Ru1-C2
Ru2-Ru1-C3
C1-Ru1-C2
C1-Ru1-C3
Ru1-Ru2-N1
Ru1-Ru2-C1
Ru1-Ru2-C2
48.7(1)
49.1(1)
98.8(1)
96.0(2)
87.1(2)
92.9(1)
50.4(1)
50.2(1)
N1-Ru1-C1
N1-Ru2-C2
Ru2-N1-C14
Ru1-C1-Ru2
Ru1-C2-Ru2
Ru1-C3-O1
N1-C14-C15
85.3(2)
83.3(2)
173.1(4)
80.8(2)
80.6(2)
178.7(5)
178.1(5)
a
Bond lengths in Å and bond angles in deg.
Ru2(µ-CH2)2(CO)2 (1) (ν(CO) 1961, 1923 cm-1 (in MeCN))
resulted in, at first, complete isomerization to the cis
isomer (ν(CO) 1961 cm-1 10
and then the formation of 2
)
(ν(CO) 1909 cm-1), which was isolated in a quantitative
yield after crystallization from CH3CN (eq 1). The
spectral features of 2 ((1) 1H NMR spectrum containing
an MeCN signal (δ 0.82) in addition to two Cp signals
(δ 4.59 and 4.91) and a pair of µ-CH2 signals (δ 7.28 (s,
2H), 8.86 (s, 2H)); (2) absence of a bridging CO stretch-
ing vibration) support its formulation as Cp2Ru2(µ-
CH2)2(CO)(MeCN) (2), and a molecular structure with
the cis configuration has been confirmed by X-ray
crystallography (Figure 1). The structural parameters
listed in Table 1 are quite similar to those of the starting
compound 1,4 and the MeCN ligand is coordinated to
Ru2 in an essentially linear fashion (Ru2-N1-C14,
173.1(4)°; N1-C14-C15, 178.1(5)°). Complex 2 is found
to be more stable than the mono(µ-methylene) species
5.
Resu lts a n d Discu ssion
Syn th esis a n d Ch a r a cter iza tion of th e MeCN
Ad d u ct of a Bis(µ-m eth ylen e) Sp ecies, Cp 2Ru 2(µ-
CH2)2(CO)(MeCN) (2). Irradiation (6 h) of an MeCN
solution of an isomeric mixture of cis- and trans-Cp2-
(7) (a) Fildes, M. J .; Knox, S. A. R.; Orpen, A. G.; Turner, M. L.;
Yates, M. I. J . Chem. Soc., Chem. Commun. 1989, 1680. (b) Howard,
J . K.; Knox, S. A. R.; Terril, N. J .; Yates, M. I. J . Chem. Soc., Chem.
Commun. 1989, 640. (c) Adams, P. Q.; Davies, D. L.; Dyke, A. F.; Knox,
S. A. R.; Mead, K. A.; Woodward, P. J . Chem Soc., Chem. Commun.
1983, 222. (d) 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.
(8) Akita, M.; Hua, R.; Knox, S. A. R.; Moro-oka, Y.; Nakanishi, S.;
Yates, M. I. Chem. Commun. 1997, 51.
(9) (a) Akita, M.; Oku, T.; Hua, R.; Moro-oka, Y. J . Chem. Soc., Chem.
Commun. 1993, 1670. (b) Akita, M.; Hua, R.; Oku, T.; Tanaka, M.;
Moro-oka, Y. Organometallics 1996, 15, 4162.
(10) Ueno, K.; Hamashima, N.; Ogino, H. Organometallics 1992, 11,
1435 and references cited therein.

5574 Organometallics, Vol. 16, No. 25, 1997
Akita et al.
Rea ction of 2 w ith Hyd r osila n es: Oxid a tive
Ad d ition of th e H-Si Bon d a n d F or m a tion of
µ-Meth ylen e-µ-silylen e Com p lexes 8 Accom p a n ied
by Elim in a tion of CH4. Reaction of the mono(µ-
methylene) derivative 5 with hydrosilane resulted in
H-Si oxidative addition to give the hydrido-silyl-µ-
methylene species Cp2Ru2(µ-CH2)(H)(SiR3)(CO)2 (6)
(Scheme 2).9 As for the bis(µ-methylene) species 2, two
types of reactions ((1) oxidative addition of the H-Si
bond giving Cp2Ru2(µ-CH2)2(CO)(H)(SiR3) (7) and (2)
formation of µ-methylene-µ-silylene complexes Cp2Ru2-
(µ-CH2)(µ-SiR2)(CO)(H)(SiR3) (8)) have been observed
(eq 2). The reaction of dihydrosilane will be described
at first, because the reaction of trialkylhydrosilane is
sluggish.
The structure of 8a and formation of methane suggest
that 8a may arise from interaction of 7a with H2SiEt2.
Actually, treatment of an isolated sample of 7a with H2-
SiEt2 led to the quantitative formation of 8a (eq 3). Thus
it has been confirmed that reaction of 2 with H2SiEt2
produces 7a , which is then converted to 8a through
interaction with excess H2SiEt2 with concomitant elimi-
nation of an equimolar amount of methane. However,
because a considerable amount of 8a was formed even
at an early stage of the reaction, selective synthesis of
7a was unsuccessful.
The HSiR3 adducts of the mono(µ-methylene) species
(6; Scheme 1) exhibit complicated facile exchange pro-
cesses, as we reported previously.9 Similarly, the in-
tramolecular H-D exchange between the hydride and
methylene hydrogen atoms (eq 4) and the intermolecu-
lar exchange of the (H)(SiHEt2) parts with external
hydrosilane (eq 5) were also observed for the bis(µ-
methylene) complex 7a . However, it took more than 4
days to attain an equilibrium. In the case of 6, the
intramolecular exchange corresponding to eq 4 was
completed upon addition of HSiR3 to 5, and the inter-
molecular exchange equilibrium corresponding to eq 5
was attained after a couple of hours. Thus, 7a has
proved to be rather rigid, though it is anticipated that
reductive elimination from a higher valent Ru(V) center
may be a more facile process compared to that from a
Ru(III) species (6). The exchange processes would follow
pathways similar to those of the mono(µ-methylene)
species 6:9 reversible reductive elimination and oxida-
tive addition of the hydride and methylene groups (eq
4) and reductive elimination of H-SiHEt2 followed by
addition of external D2SiEt2 (eq 5).
(i) Rea ction w ith Dih yd r osila n es. Treatment of
2 with H2SiEt2 in benzene afforded the two hydride
complexes 7a (36% yield) and 8a (60% yield) after TLC
separation (eq 2). The minor product 7a has been
assigned to the oxidative-addition product Cp2Ru2(µ-
1
CH2)2(CO)(H)(SiHEt2) on the basis of its H NMR data
containing two µ-CH2 and hydride signals (δH 8.05, 7.07
(2H × 2, s × 2, (µ-CH2)2), 4.79, 4.67 (5H × 2, s × 2,
Cp2), 3.25 (1H, m, SiH), 1.46-0.94 (10H, m, SiEt2),
-15.1 (1H, s, RuH)), which are similar to those for the
HSnPh3 adduct 9b characterized crystallographically
(see below). Complex 7 is analogous to 6′, the undetect-
able intermediate assumed for formation of 6 (Scheme
2), and its isolation supports the viability of 6′. The
other product 8a has been characterized as the µ-me-
thylene-µ-silylene complex Cp2Ru2(µ-CH2)(µ-SiEt2)-
1
(CO)(H)(SiHEt2) on the basis of its H NMR spectrum
Reaction of H2SiPh2 produced a mixture of three
hydride complexes (δH -13.4, -13.7, -14.2), from which
the µ-methylene-µ-silylene complex Cp2Ru2(µ-CH2)(µ-
SiPh2)(CO)(H)(SiHPh2) 7b (δH -13.4) was isolated in
38% yield after TLC separation (eq 2). The other two
products could not be isolated due to decomposition on
TLC. In this case, too, formation of a comparable
amount of CH4 (45% yield) was observed.
(ii) Rea ction w ith Mon oh yd r osila n e. The reac-
tion with trialkylhydrosilanes such as HSiMe3 and
HSiEt3 was sluggish (eq 2). The reaction product from
HSiMe3 was assigned to Cp2Ru2(µ-CH2)2(CO)(H)(SiMe3)
(7c; δH(C6D6) 7.94, 6.00 (2H × 2, d × 2, J ) 3.0 Hz,
µ-CH2), 4.62, 4.45 (Cp), -15.4 (hydride)) by comparison
of its spectral data with those of 7a . However, 7c could
not be isolated in pure form owing to its thermal
instability. HSiEt3 did not react with 2 at ambient
temperature, in contrast to the high reactivity of 5, but
indicating loss of one of the two µ-methylene ligands
and incorporation of the two SiEt2 units (δH 8.03, 5.93
(1H × 2, d × 2, J ) 3.0 Hz, µ-CH2), 4.64, 4.46 (5H × 2,
s × 2, Cp2), 4.04 (1H, m, SiH), 1.46-1.02 (20H, m,
SiEt2), -15.4 (1H, s, RuH)). The spectroscopic features
are similar to those of the derivative 8e obtained from
HSiMe2Ph and characterized crystallographically (see
below). The lost methylene part was converted into
methane, as revealed by GLC analysis of the gas phase,
and the yield of CH4 (67%) was found to be comparable
to the yield of 8a (60%) (eq 2). It is notable that the
adducts 7 and 8 belong to a rare class of high-valent
organoruthenium complexes (Ru(III)-Ru(V))11 and that,
to our knowledge, 8 is the first example of a complex
containing both methylene and silylene bridges.
(11) Abel, E. W.; Stone, F. G. A.; Wilkinson, G. Comprehensive
Organometallic Chemistry II; Pergamon: Oxford, U.K., 1995; Vol. 7.

MeCN Adducts of Ru2 Bis(µ-methylene) Species
Organometallics, Vol. 16, No. 25, 1997 5575
heating at 60 °C resulted in the formation of methane
(95% yield) together with a mixture of unidentified
organometallic products.
The reaction with monohydrosilane bearing an aryl
group (HSiMe2Ph and HSiPh3) afforded a mixture of
three hydride complexes, from which µ-methylene-µ-
silylene complexes Cp2Ru2(µ-CH2)(µ-SiR2)(CO)(H)(SiMe3)
(R2) Me2 (8e; 73%), Ph2 (8f; 26%)) were isolated after
TLC separation (eq 2). The other two products could
not be isolated, owing to decomposition on TLC. Com-
plexes 8e,f should be formed via Si-Ph bond cleavage
and loss of one of the two methylene ligands (see below),
and the eliminated groups were converted to benzene
and methane, as confirmed by GLC analysis of the
mixture. The structure of 8e has been confirmed by
X-ray crystallography, though the quality of the crystal
was not satisfactory.12
F igu r e 2. Molecular structure of 9b (molecule 1) drawn
at the 30% probability level.
Rea ction of 2 w ith Hyd r osta n n a n es: F or m a tion
of Oxid a tive-Ad d ition P r od u cts 9 a n d 10. The
reaction of 2 with HSnMe3 in hexane occurred readily
at room temperature to give the oxidative-addition
product Cp2Ru2(µ-CH2)2(H)(SnR3)(CO) (9a ) as the sole
isolable organometallic product in 50% yield (eq 6). In
Ta ble 2. Selected Str u ctu r a l P a r a m eter s for 9ba
Bond Lengths
Sn1-Ru2
Ru1-Ru2
Ru1-C1
Ru1-C2
2.620(2)
2.710(2)
2.05(1)
2.05(1)
Ru1-C3
Ru2-C1
Ru2-C2
C3-O3
1.90(2)
2.12(1)
2.11(2)
1.12(2)
Bond Angles
Ru2-Ru1-C1
Ru2-Ru1-C2
Ru2-Ru1-C3
C1-Ru1-C2
C1-Ru1-C3
C2-Ru1-C3
50.5(4)
50.2(5)
90.3(6)
100.7(6
93.3(7)
88.4(7)
Sn1-Ru2-C1
Sn1-Ru2-C2
Ru1-Ru2-C1
Ru1-Ru2-C2
C1-Ru2-Ru1
78.3(3)
122.0(4)
48.5(4)
48.5(4)
97.0(6)
a
Bond lengths in Å and bond angles in deg for molecule 1 (a
the case of the reaction with HSnPh3, the hydrido-
tristannyl-µ-methylene complex Cp2Ru2(µ-CH2)(µ-H)-
(SnPh3)3(CO) (10) was obtained in addition to 9b after
TLC separation.
series).
The spectroscopic features of 9 are similar to those of
the silyl analogues 7, and the molecular structure of the
stannyl-bis(µ-methylene) complex 9b has been deter-
mined by X-ray crystallography (Figure 2 and Table 2).
It is notable that the CH2-RuV distances are longer
than the CH2-RuIII distances by 0.06 Å. Although it
has been established that alkyl-hydride complexes
readily undergo reductive elimination,13 9 is stable and
(12) Crystallographic data for 8e: triclinic, space group P1h, a )
15.489(8) Å, b ) 16.071(8) Å, c ) 10.374(5) Å, R ) 93.15(4)°, â )
114.84(3)°, γ ) 90.53(5)°, V ) 2338(4) Å3, Z ) 4 (with two crystallo-
graphically independent molecules). The methylene and silylene
ligands bridge the ruthenium centers in a symmetrical manner, and
the configuration of the two Cp rings is found to be cis. The Ru-CH2
and Ru-Si distances are comparable to those in related µ-methylene
and µ-silylene complexes.
F igu r e 3. Molecular structure of 10 drawn at the 30%
probability level.
no dynamic behavior is observed at room temperature.14
The structure of 10, also characterized by X-ray crystal-
lography (Figure 3 and Table 3), contains three SnPh3
(14) Stable µ-methylene-hydride complexes such as Cp2Ta(µ-CH2)2-
IrCp*(H) and Cp2Ta(µ-CH2)2M(H)2(L) (M ) Rh, Ir; L ) CO, PPh3) have
been reported: (a) Hostetler, M. J .; Butts, M. D.; Bergman, R. G. J .
Am. Chem. Soc. 1993, 115, 2743. (b) Butts, M. D.; Bergman, R. G.
Organometallics 1994, 13, 2668.
(13) Collman, J . P.; Hegedus, L. S.; Norton, J . R.; Finke, R. G.
Principles and Applications of Organotransition Metal Chemistry;
University Science Books: Mill Valley, CA, 1987.

5576 Organometallics, Vol. 16, No. 25, 1997
Akita et al.
Ta ble 3. Selected Str u ctu r a l P a r a m eter s for 10a
Bond Lengths
Sn1-Ru1
Sn2-Ru2
Ru1-Ru2
Ru1-C1
2.640(3)
2.670(3)
2.875(4)
2.06(3)
Ru1-C2
Ru2-C1
C2-O2
1.75(4)
2.02(3)
1.19(3)
Bond Angles
Sn1-Ru1 Ru2
Su1-Ru1-C1
Sn1-Ru1-C2
Ru2-Ru1-C1
Ru2-Ru1-C2
C1-Ru1-C2
Sn2-Ru2-Sn3
110.6(1)
75.9(7)
80(1)
44.7(7)
81(1)
Sn2-Ru2-Ru1
Sn2-Ru2-C1
Sn3-Ru2-Ru1
Sn3-Ru2-C1
Ru1-Ru2-C1
Ru1-C1-Ru2
Ru1-C2-O2
105.7(1)
72.0(8)
88.2(1)
127.8(8)
45.8(8)
90(1)
102(1)
108.1(1)
174(3)
a
Bond lengths in Å and bond angles in deg.
groups, and one of the two methylene ligands in 2 is
found to be eliminated. In accord with this structure,
formation of methane was detected by GLC analysis.
Sn-Ph bond cleavage leading to a µ-methylene-µ-
stannylene species analogous to 8 was not observed,
although in the case of the reaction of 5 with HSnPh3,
Sn-Ph bond cleavage led to functionalization of the
SnPh3 moiety.9
Rea ction of 2 w ith Hyd r ogen : F or m a tion of th e
Tetr a n u clea r µ3-Meth ylid yn e Com p lex 11 a n d In -
ter con ver sion betw een Meth ylen e a n d Meth yli-
d yn e-Hyd r id e Sp ecies on a Tetr a n u clea r Sys-
tem .15 When a benzene solution of 2 was stirred under
H2 (1 atm) overnight at room temperature, black
precipitates 11 were obtained almost quantitatively and
formation of CH4 (104% yield based on 2) was observed
by GLC analysis (eq 7). A 1H NMR spectrum of 11
F igu r e 4. Molecular structure of 11 (molecule 1) drawn
at the 30% probability level.
Ta ble 4. Selected Str u ctu r a l P a r a m eter s for 11a
Bond Lengths
Ru11-Ru12
Ru11-Ru13
Ru11-Ru14
Ru11-C12
Ru11-C13
Ru12-Ru13
Ru12- Ru14
Ru12-C11
Ru12-C12
Ru13-C11
Ru13-C13
Ru14-C11
Ru14-C12
Ru14-C13
C12-O12
2.716(2)
2.718(2)
2.7073)
2.05(1)
2.04(2)
2.723(2)
2.701(5)
2.06(1)
2.04(2)
2.06(1)
2.00(2)
2.06(1)
2.13(1)
2.07(2)
1.23(2)
1.27(2)
Ru21-Ru22
Ru21-Ru23
Ru21-Ru24
Ru21-C22
Ru21-C23
Ru22-Ru23
Ru22-Ru24
Ru22-C21
Ru22-C22
Ru23-C21
Ru23-C23
Ru24-C21
Ru24-C22
Ru24-C23
C22-O22
2.727(5)
2.727(4)
2.6893)
2.00(1)
2.03(1)
2.720(2)
2.695(2)
2.16(1)
1.99(1)
2.15(1)
2.00(2)
2.16(2)
2.06(1)
2.10(1)
1.27(2)
1.26(2)
C13-O13
C23-O23
Bond Angles
59.75(9)-60.87(9) Ru-C11, C21-O 127-133(1)
Ru-C11, C21-Ru 77.4-82.9(5)
Ru-C12, C22-Ru 80.6-86.0(5)
Ru-Ru-Ru
Ru-C12, C22-O 127-133(1)
a
Bond lengths in Å and bond angles in deg.
contains three Cp resonances in a 5:10:5 ratio (δH-
(CDCl3) 5.31, 5.00, 4.78) in addition to two singlets in
very low and high field (δH15.0 (1H), -12.6 (1H)).
Although a satisfactory 13C NMR spectrum has not been
obtained owing to the low solubility, the lower energy
CO stretching vibration (1617 cm-1) indicates the pres-
ence of face-capping CO ligands.
The structure was finally determined by X-ray crys-
tallography, and one of the two independent molecules
is reproduced in Figure 4 (bond distances and angles
are given in Table 4). Complex 11 can be described as
the tetraruthenium µ3-methylidyne-µ3-hydrido complex
Cp4Ru4(µ3-CH)(µ3-H)(µ3-CO)2, which is consistent with
the FD-MS result (M+ at m/z 734 for the 101Ru isoto-
pomer). The core structure of 11 consists of the tetra-
hedral Ru4 array, and all the equilateral Ru3 triangles
with the averaged Ru-Ru distance of 2.7 Å are capped
by the four µ3 face-capping ligands (1 CH, 1 H, and 2
CO). Cluster 11 is an electron-precise tetrahedral
cluster with 60 cluster valence electrons (CVE). All the
above-mentioned spectral features are consistent with
a mirror-symmetrical structure, and the highly deshield-
ed 1H NMR signal (δH 15.0) is assigned to the µ3-CH
ligand.16
In order to confirm the distribution of the µ-CH2
hydrogen atoms, Cp2Ru2(µ-CD2)2(CO)(MeCN) 2-d4 (>95%
deuterated) was treated with H2. As a result, Cp4Ru4-
(µ3-CD)(µ3-D)(µ3-CO)2 11-d2 was obtained, though the
lower isotopic purity (ca. 60% as determined by 1H
NMR) indicated occurrence of H-D exchange processes
to a considerable extent. The labeling experiments
confirm that the C-H bond in the µ-CH2 functional group
is cleaved during formation of 11.
The C-H cleavage process can be reversed by carbon-
ylation. Stirring a benzene solution of 11 under a CO
atmosphere (10 atm) at 80 °C afforded a mixture of the
(16) (µ3-CH)M3 complexes: (a) M ) Co: Seyferth, D.; Hallgren, J .
E.; Hung, P. L. K. J . Organomet. Chem. 1973, 50, 265. (b) M ) Ru:
Kakigano, T.; Suzuki, H.; Igarashi, M.; Moro-oka, Y. Organometallics
1990, 9, 2192. (c) M ) Os: Shapley, J . R.; Cree-Uchiyama, M. E.; St.
George, G. M.; Churchill, M. R.; Bueno, C. J . Am. Chem. Soc. 1983,
105, 140. (d) M ) Ru: Keister, J . B.; Horling, T. L. Inorg. Chem. 1980,
19, 2304. (e) M ) Fe: Vites, J . C.; J acobsen, G.; Dutta, T. K.; Fehlner,
T. P. J . Am. Chem. Soc. 1985, 107, 5563. (f) Kolis, J . W.; Holt, E. M.;
Shriver, D. F. J . Am. Chem. Soc. 1983, 105, 7307. (g) M ) Os: Calvert,
R. B.; Shapley, J . R. J . Am. Chem. Soc. 1977, 99, 5225. (h) M ) Rh:
Dimas, P. A.; Duesler, E. N.; Lawson, R. J .; Shapley, J . R. J . Am. Chem.
Soc. 1980, 102, 7787. (i) Herrmann, W. A.; Plank, J .; Riedel, D.;
Weidenhammer, K.; Guggolz, E.; Balbach, B. J . Am. Chem. Soc. 1981,
103, 63. (j) M3 ) Co, Cr, Mo, W, Ni: Duffy, D. N.; Kassis, M. M.; Rae,
A. D. J . Organomet. Chem. 1993, 460, 97. (k) Schacht, H. T.;
Vahrenkamp, H. J . Organomet. Chem. 1990, 381, 261. (l) Akita, M.;
Noda, K.; Takahashi, Y.; Moro-oka, Y. Organometallics 1995, 14, 5209.
(15) A preliminary report has appeared. Akita, M.; Hua, R.; Moro-
oka, Y. J . Organomet. Chem. 1997, 539, 205.

MeCN Adducts of Ru2 Bis(µ-methylene) Species
Organometallics, Vol. 16, No. 25, 1997 5577
Sch em e 3
mono(µ-methylene) complex 1 and the carbonyl complex
Cp2Ru2(CO)4 quantitatively. Thus, carbonylation in-
duced recombination of the µ3-CH and µ3-H moieties
associated with fragmentation of the tetranuclear core
into two dinuclear species.
P la u sible Mech a n ism s for Rea ction of 2 w ith
H-X (X ) SiR 3, Sn R 3, H). The reactions of 2 with
H-X (X ) SiR3, SnR3, H) can be interpreted in terms
of the mechanisms summarized in Scheme 3, which are
based on the structure of the products as well as the
methane formation mechanism from 5 studied previ-
ously.9
The initial step should be oxidative addition of the
H-X bond, giving the hydrido-bis(µ-methylene) inter-
mediate. In some cases, the reaction is terminated at
this stage to give the adduct 7 or 9. Subsequent C-H
reductive elimination produces the coordinatively un-
saturated methyl intermediate I. The exchange pro-
cesses of 7 (eqs 4 and 5) are viable, if the initial two
steps are reversible. Oxidative addition of a second
H-X molecule and reductive elimination of methane
affords another coordinatively unsaturated intermedi-
ate, II. In the case of the reaction with H2SiEt2, Si-H
bond cleavage gives the µ-silylene intermediate III,
rearrangement of which leads to the final product 8.
Another mechanism involving a terminal silylene in-
termediate formed via intramolecular oxidative addition
of the H-Si bond in I might be possible. On the other
hand, the reaction with arylsilane should follow oxida-
tive addition of the Ph-Si bond in II, giving the phenyl
intermediate IV. Final hydrogenolysis may furnish 8
along with benzene, though the mechanism is not clear.
A small amount of H2 was actually detected in the gas
phase of a reaction mixture. Finally, the formation of
the tristannyl complex 10 should involve H-Sn oxida-
tive addition to II.
The formation of the tetranuclear cluster 11 can be
explained formally in terms of coupling of highly
unsaturated intermediates V and VI resulting from
hydrogenolysis of 2. Because 11 is obtained in quanti-
tative yield, V should be trapped by VI as soon as V is
formed. The initial tetranuclear coupling product Cp4-
Ru4(µ-CH2)(CO)2 is still a coordinatively unsaturated
species with 58 CVE, and therefore, subsequent cleav-
age of the H-CH bond would lead to the electron-precise
structure with 60 CVE. Similar oxidative addition of a
µ-CH2 ligand in 5 has a precedent as reported by Stone
et al.17 In this system, single and double C-H activa-
tion by Pt(CH2dCH2)(PR3) leads to the tetranuclear Ru2-
Pt2(µ4-CH)(µ-H) (methylidyne) and Ru2Pt2(µ4-C)(µ-H)2
(carbide) cluster compounds, respectively. Activation of
a C-H bond in cluster compounds is a well-documented
process, and interconversion of CHx species on poly-
metallic systems has precedents.13,18
C-C Cou p lin g of 2 w ith Alk yn es Lea d in g to
Meta lla cyclic P r od u cts 12. Knox et al. reported the
C-C coupling reaction of the mono(µ-methylene) species
5 with unsaturated hydrocarbons leading to metalla-
cyclic products.7 Then the bis(µ-methylene) species 2
(17) (a) Davies, D. L.; J effery, J . C.; Miguel, D.; Sherwood, P.; Stone,
F. G. A. J . Chem. Soc., Chem. Commun. 1987, 454. (b) Davies, D. L.;
J effery, J . C.; Miguel, D.; Sherwood, P.; Stone, F. G. A. J . Organomet.
Chem. 1990, 383, 463. See also: (c) J effery, J . C.; Parrot, M. J .; Stone,
F. G. A. J . Organomet. Chem. 1990, 382, 225.
(18) Shriver, D. F.; Kaesz, H. D.; Adams, R. D. The Chemistry of
Metal Cluster Complexes; VCH: New York, 1990.

5578 Organometallics, Vol. 16, No. 25, 1997
Akita et al.
Ta ble 5. Selected Str u ctu r a l P a r a m eter s for 12a a
Bond Lengths
Ru1-Ru2
Ru1-C1
Ru1-C2
Ru1-C3
Ru1-C4
Ru2-C1
Ru2-C4
Ru2-C11
C11-O11
C2-C3
2.693(2)
2.08(2)
2.18(2)
2.18(2)
2.14(2)
2.10(2)
2.13(2)
1.85(2)
1.15(2)
1.51(3)
1.47(3)
1.37(3)
Ru3-Ru4
Ru3-C31
Ru3-C32
Ru3-C33
Ru3-C34
Ru4-C31
Ru4-C34
Ru4-C41
C41-O41
C32-C33
C33-C34
C34-C35
2.696(2)
1.96(3)
2.22(2)
2.16(2)
2.07(2)
2.05(2)
2.03(2)
1.86(2)
1.11(2)
1.40(3)
1.48(3)
1.54(3)
C3-C4
C4 -C5
Bond Angles
Ru2-Ru1-C1
Ru2-Ru1-C2
Ru2-Ru1-C3
Ru2-Ru1-C4
C1-Ru1-C2
C1-Ru1-C3
C1-Ru1-C4
C2-Ru1-C3
C2-Ru1-C4
C3-Ru1-C4
Ru1-Ru2-C1
Ru1-Ru2-C4
Ru1-Ru2-C11
C1-Ru2-C4
C1-Ru2-C11
C4-Ru2-C11
Ru1-C1-Ru2
Ru1-C2-C3
Ru1-C3-C2
Ru1-C3-C4
C2-C3-C4
50.1(7)
80.9(6)
75.2(5)
50.7(5)
82.8(8)
107.8(8)
99.7(8)
40.5(8)
74.3(8)
39.9(7)
49.5(6)
51.0(5)
85.0(6)
99.4(8)
91.2(8)
93.7(8)
80.4(7)
69(1)
Ru4-Ru3-C31
Ru4-Ru3-C32
Ru4-Ru3-C33
Ru4-Ru3-C34
C31-Ru3-C32
C31-Ru3-C33
C31-Ru3-C34
C32-Ru3-C33
C32-Ru3-C34
C33-Ru3-C34
Ru3-Ru4-C31
Ru3-Ru4-C34
Ru3-Ru4-C41
C31-Ru4-C34
C31-Ru4-C41
C34-Ru4-C41
Ru3-C31-Ru2
Ru3-C32-C33
Ru3-C33-C32
Ru3-C33-C34
C32-C33-C34
Ru3-C34-Ru4
Ru3-C34-C33
Ru4-C34-C33
49.3(5)
81.0(7)
76.3(6)
48.3(6)
84.7(9)
107.7(8)
96.1(8)
37.3(7)
70.6(8)
40.8(7)
46.4(7)
49.7(5)
83.5(9)
94.6(9)
89.2(9)
95(1)
F igu r e 5. Molecular structure of 12a (molecule 1) drawn
at the 30% probability level.
was also subjected to reaction with unsaturated
hydrocarbons.
Treatment of 2 with 1-alkyne (RCtCH: R ) Ph, Me3-
Si) in benzene at ambient temperature afforded the
adduct Cp2Ru2(µ-CH2)[µ-C(R)-CHdCH2](CO) (12) (eq 8).
The 1H NMR spectrum indicates the presence of a vinyl
functional group (three dd signals: 12a , δH(CDCl3) 4.87
(1H, dd, J ) 6.4 and 7.8 Hz, R-CHd), 2.70 (1H, d, J )
6.4Hz, CH2), -0.12 (1H, d, J ) 7.8 Hz, CH2); 12b, δH-
(CDCl3) 4.58 (1H, dd, J ) 4.7 and 6.6 Hz, R-CHd), 2.70
(1H, dd, J ) 1.2 and 6.4 Hz, CH2), -0.12 (1H, dd, J )
1.2 and 4.4 Hz, CH2)) in addition to one µ-methylene
ligand left unreacted (12a , δH 9.07 (1H, s), 8.32 (1H, s);
12b, δH 8.97 (1H, s), 8.42 (1H, s)). The vinyl group
should be a part of the C(R)CHdCH2 linkage arising
from coupling of one of the two methylene ligands with
1-alkyne. It is notable that no other isomer has been
detected and the insertion of 1-alkyne proceeds in a
specific manner. As established for the Ph derivative
12a by X-ray crystallography (Figure 5 (one of the two
independent molecules) and Table 5), the vinylphenyl-
alkylidene part interacts with the diruthenium core in
a µ-η1:η3-fashion and contribution of the allylic structure
12′ and the metallacyclopentene structure 12′′ is evident
from the three similar C-Ru1 distances (Ru1-C2,
2.18(2) Å; Ru1-C3, 2.18(2) Å; Ru1-C4, 2.13(2) Å).
84.3(9)
69(1)
73(1)
69(1)
68(1)
122(1)
78.3(6)
71(1)
66(1)
119(2)
82.0(8)
72(1)
Ru1-C4-Ru2
Ru1-C4-C3
Ru2-C4-C3
111(1)
118(1)
a
Bond lengths in Å and bond angles in deg.
The formation of 12 is explained in terms of insertion
of the CtC bond into the Ru-CH2 bond followed by
rearrangement of the σ- and π-bonds. Thus, single C-C
coupling of the µ-methylene ligand with the external
substrate was observed. Attempted double C-C cou-
pling by addition of a 2e-donor (CO, PR3) was unsuc-
cessful, although it was reported that heating 12c in
refluxing xylene resulted in the formation of a C4
product.7d
Reaction of 2 with olefinic substrates was also exam-
ined to see if C-C bond formation took place or not.
However, ethene and R-methylstyrene left 2 unreacted,
even when the mixture was heated at 50 °C. On the
other hand, reaction with ethyl acrylate, bearing an
electron-withdrawing substituent, resulted in simple
ligand replacement to give an isomeric mixture (5:1) of
the η2-coordinated complex Cp2Ru2(µ-CH2)2(CO)(η2-
CH2dCH-COOEt) (13; 56% yield) (eq 9), which was
Diphenylacetylene also readily reacted with 2 to
afford the adduct Cp2Ru2(µ-CH2)[µ-C(Ph)C(Ph)dCH2]-
(CO) (12c) in 74% yield (eq 8). The same compound was
already prepared via an alternative route,7d which is a
reversed version of the present synthesis, that is,
addition of a methylene unit (CH2dN2) to the µ-acety-
lene species, Cp2Ru2(µ-η2:η2-PhCtCPh)(µ-CO). Ethyne
(HCtCH) also readily reacted with 2, but a complicated
mixture was obtained.
analogous to the structurally characterized mono(µ-
methylene) derivative Cp2Ru2(µ-CH2)(CO)2(η2-CH2dCH-
COOMe).6 Attempted C-C coupling under thermal
conditions was unsuccessful, and instead decomposition
was observed. Upon treatment with CO, 13 reverted
to the carbonyl complex Cp2Ru2(µ-CH2)2(CO)2.
C-C Cou p lin g of 2 w ith Dia zoa lk a n es To Give
Vin ylid en e Com p lex 14. Recently we reported that

MeCN Adducts of Ru2 Bis(µ-methylene) Species
Organometallics, Vol. 16, No. 25, 1997 5579
Ta ble 6. Selected Str u ctu r a l P a r a m eter s for 14a
Bond Lengths
Ru1-Ru2
Ru1-C1
Ru1-C3
Ru1-C51
Ru1-C52
Ru2-C1
Ru2-C3
Ru2-C4
C4-O4
2.680(2)
1.97(1)
2.12(1)
2.21(1)
2.31(1)
2.06(1)
2.03(1)
1.82(1)
1.15(1)
1.33(1)
C2-C31
C2-C41
C3-C51
C3-C61
C51-C52
C51-C56
C52-C53
C53-C54
C54-C55
C55-C56
1.54(1)
1.53(2)
1.51(1)
1.44(1)
1.42(1)
1.43(1)
1.47(2)
1.35(2)
1.34(2)
1.37(2)
C1-C2
Bond Angles
C1-Ru2-C3
C1-Ru2-C4
C3-Ru2-C4
Ru1-C1-C2
Ru2-C1-C2
Ru1-C3-Ru2
Ru2-C4-O4
Ru1-C51-C3
Ru1-C51-C52
Ru1-C51-C56
92.8(5)
88.1(5)
89.3(5)
146(1)
130.6(9)
80.4(4)
174(1)
66.1(6)
75.6(7)
120.0(8)
C3-C51-C52
C3-C51-C56
C52-C51-C56
Ru1-C52-C51
Ru1-C52-C53
C51-C52-C53
C52-C53-C54
C53-C54-C55
C54-C55-C56
C51-C56-C55
118(1)
122(1)
117(1)
68.0(6)
120.9(8)
118(1)
119(1)
122(1)
121(1)
121(1)
a
Bond lengths in Å and bond angles in deg.
F igu r e 6. Molecular structure of 14 drawn at the 30%
probability level.
(d, J ) 168 Hz)), and C1 and C3 are located at δC 253.6
the labile mono(µ-methylene) species 5 reacts with
various diazoalkanes to give olefinic products through
C-C coupling (Scheme 2).8 Although the di(µ-methyl-
ene) species 2 was also found to readily react with
diazoalkanes, the reaction was generally complicated
(N2CH2, N2CHPh, N2CHCOOEt) and a clean reaction
was observed only for the reaction with diphenyldi-
azomethane (N2dCPh2) (eq 10). Although the simple
1H NMR spectrum of the product Cp2Ru2(µ-CdCPh2)-
(µ-η1:η3-CPh2)(CO) (14) containing Cp and Ph signals
and 99.6, respectively. This type of coordination is
19
rather usual, and Cp2Ru2(µ-η1:η3-CPh2)(CO)2 may be
raised as a typical example. The structure of 14
suggests that disproportionation of the two µ-methylene
ligands gives rise to the vinylidene quaternary carbon
atom and methane (2CH2 f C + CH4). As expected,
methane was detected in the gas phase (21% yield).
A plausible formation mechanism of 14 is depicted
in Scheme 4. The initial reaction may be similar to the
C-C coupling of the mono(µ-methylene) species 5.
Successive incorporation of the CPh2 group as an η1-
ligand, C-C coupling, and C-H oxidative addition
afford the hydrido-µ-alkenyl intermediate VII. Sub-
sequent reductive elimination of the H and µ-CH2 parts
gives the coordinatively unsaturated methyl intermedi-
ate VIII. Oxidative addition of the R-C-H bond and
rearrangement give the µ-vinylidene-hydrido-methyl
intermediate IX. Final reductive elimination of meth-
ane followed by coordination of a second molecule of
diazoalkane furnishes 14. According to the scheme,
multiple C-C coupling is hampered by the reductive
elimination (VII f VIII), resulting in the loss of the
CH2 functional group.
Syn th esis a n d Rea ction of Bis(µ-m eth ylen e) Bis-
(a ceton itr ile) Sp ecies 3. Irradiation of an MeCN
solution of 1 produced 2 as described above. Further
irradiation (ca. 20 h) caused disappearance of the ν(CO)
vibration. The resulting species, formulated as the bis-
(µ-methylene) bis(acetonitrile) species Cp2Ru2(µ-CH2)2-
(CO)2 (3), decomposed to a considerable extent after
evaporation of the solvent and, therefore, was charac-
terized on the basis of the following experiments (Scheme
5).
(δH 7.9-6.5 (Ph), 4.35, 4.05 (Cp2)) along with small
signals around 2.6 ppm suggested loss of the µ-CH2
functional groups, the product could not be character-
ized by spectral data alone, and thus, 14 was subjected
to an X-ray diffraction study. The molecular structure
shown in Figure 6 (bond distances and angles are given
in Table 6) contains the µ-diphenylvinylidene ligand in
addition to the µ-η1:η3-diphenylmethylene ligand, which
interacts with Ru1 in a η3-mode (π-benzyl structure
14′: Ru1-C3, 2.12(1) Å; Ru1-C51, 2.21(1) Å; Ru1-C52,
2.31(1) Å). Upon coordination of the benzylic part the
bond lengths of the C56-C51-C52-C53 part (1.42-
1.47 Å) of the phenyl ring is slightly elongated compared
to those of the C53-C54-C55-C56 part (1.34-1.37 Å)
owing to partial localization of the aromatic π-electrons.
In accord with this structure, the 1H and 13C NMR
signals of the C52-H moiety are observed at consider-
ably higher field (δH 2.66 (dd, 5.9 and 1.5 Hz), δC 72.9
The 1H NMR experiment in CD3CN indicated the
formation of the single, symmetrical species 3 contain-
ing a single Cp resonance at δ 5.23. Treatment of 3 with
2e-donors (CO, cyclohexyl isocyanide (NCCy)) gave
adducts (1 and 15) incorporating the 2e-donor at each
(19) (a) Davis, D. L.; Knox, S. A. R.; Mead, K. A.; Morris, M. J .;
Woodward, P. J . Chem. Soc., Dalton Trans. 1984, 2293. See also: (b)
Messerle, L.; Curtis, M. D. J . Am. Chem. Soc. 1980, 102, 7789. (c)
J effery, J . C.; Laurie, J . C. V.; Moore, I.; Razay, R.; Stone, F. G. A. J .
Chem. Soc., Dalton Trans. 1984, 1563.

5580 Organometallics, Vol. 16, No. 25, 1997
Akita et al.
Sch em e 4
Ta ble 7. Selected Str u ctu r a l P a r a m eter s for 16a
Bond Lengths
Ru1-Ru2
Ru1-C1
Ru1-C2
Ru1-C3
Ru1-C4
Ru2-C1
Ru2-C2
2.6574(6)
2.049(4)
2.039(4)
2.192(4)
2.155(4)
2.053(4)
2.041(4)
Ru2-C5
Ru2-C6
C3-C4
C3-C7
C4-C5
C5-C6
C6-C7
2.159(4)
2.186(4)
1.410(6)
1.494(6)
1.492(6)
1.405(6)
1.507(6)
Bond Angles
Ru2-Ru1-C1
Ru2-Ru1-C2
Ru2-Ru1-C3
Ru2-Ru1-C4
C1-Ru1-C2
C1-Ru1-C3
C1-Ru1-C4
C2-Ru1-C3
C2-Ru1-C4
C3-Ru1-C4
Ru1-Ru2-C1
Ru1-Ru2-C2
Ru1-Ru2 C5
Ru1-Ru2-C6
49.7(1)
49.4(1)
85.6(1)
74.3(1)
94.4(2)
111.3(2)
77.0(2)
85.3(2)
103.6(2)
37.8(1)
49.6(1)
49.3(1)
74.4(1)
85.9(1)
C1-Ru2-C2
C1-Ru2-C5
C1-Ru2-C6
C2-Ru2-C5
C2-Ru2-C6
C5-Ru2-C6
Ru1-C1-Ru2
Ru1-C2-Ru2
C4-C3-C7
C3-C4-C5
C4-C5-C6
C5-C6-C7
C3-C7-C6
94.3(2)
77.1(2)
111.4(2)
103.6(2)
85.6(2)
37.7(1)
80.8(1)
81.3(1)
110.1(4)
107.0(4)
107.7(4)
109.5(4)
102.0(4)
F igu r e 7. Molecular structure of 16 drawn at the 30%
probability level.
Sch em e 5
a
Bond lengths in Å and bond angles in deg.
ylene bridges, has been examined with the emphasis
on (1) reduction with H-X (X) SiR3, SnR3, H) and (2)
C-C coupling with alkynes and diazoalkanes, and the
results are summarized in Scheme 6.
As for the first aspect, methane is evolved in moderate
yields under milder conditions (at room temperature)
compared to those for the mono(µ-methylene) derivative
5.9 The methane formation mechanism should be
essentially similar to that discussed for 5. However, the
mechanism involving oxidative addition of H-X, Si-
Ph, and C-H bonds is rather complicated as indicated
by the dependence of the structure of the organometallic
products (8, 10, and 11) on the structure of the reducing
agent. In addition, only one of the two methylene
ligands is converted to methane, and the other ligand
remains as a supporting ligand. Possible origins of the
dissimilar reactivity are (i) the nature of the other
bridging ligand (µ-CH2 (2) vs µ-CO (5)) and (ii) the
oxidation state of the Ru centers (e.g. MeCN com-
ruthenium center in quantitative yields. Although
olefins did not react with 3 at all, conjugated dienes
produces 1:1 adducts. Cyclopentadiene afforded com-
plex 16 as a single product, whereas butadiene gave a
mixture of s-cis- and s-trans-η4-diene isomers, which
interconverted with each other upon heating at 120 °C.
The X-ray structure (Figure 7 and Table 7) indicates
that cyclopentadiene is coordinated to each Ru center
as an η2-olefin ligand, as judged by the C4-C5 distance
(1.492(6) Å) being comparable to the C(sp2)-C(sp2)
single-bond length (1.48 Å).
We also examined the reaction of 3 with HSiR3,
HSnR3, alkynes, and diazoalkanes; however, compli-
cated mixtures of products were merely obtained.
Con clu sion s. Reactivity of the diruthenium complex
Cp2Ru2(µ-CH2)2(CO)(NCMe) (2), containing two meth-
plexes: Cp2RuIII2(µ-CH2)2(CO)(NCMe) (2) vs Cp2RuII
-
2
(µ-CH2)(CO)2(NCMe) (5)). CO can be coordinated to a
metal center as a terminal as well as bridging ligand,
whereas CH2 can interact with a metal center only as a
bridging ligand and a terminal methylene species
(MdCH2) should be a high-energy species owing to less
effective back-donation from the metal center compared

MeCN Adducts of Ru2 Bis(µ-methylene) Species
Organometallics, Vol. 16, No. 25, 1997 5581
Sch em e 6
Sch em e 7
Exp er im en ta l Section
Gen er a l Con sid er a tion s. All manipulations were carried
out under an inert atmosphere by using standard Schlenk tube
techniques. Ether, hexanes, and toluene (Na-K alloy), CH2-
Cl2 (P2O5), and CH3CN (CaH2) were treated with appropriate
drying agents, distilled, and stored under argon. Chromatog-
raphy was performed on alumina (column, aluminum oxide,
activity II-IV (Merck Art. 1097); preparative TLC, aluminum
oxide 60PF254 (Type E) (Merck Art. 1103)) or silica gel
(preparative TLC, Kiesel gel 60 PF254 (Merck 1.007747)). 1H
and 13C NMR spectra were recorded on J EOL EX-90 (1H, 90
MHz), GX-270 (1H, 270 MHz; 13C, 67 MHz), EX-400 (1H, 400
MHz; 13C, 100 MHz), and GX-500 spectrometers (1H, 500 MHz;
13C, 125 MHz). Solvents for NMR measurements containing
1% TMS were dried over molecular sieves, degassed, distilled
under reduced pressure, and stored under Ar. IR and FD-
MS spectra were obtained on a J ASCO FT/IR 5300 spectrom-
eter and a Hitachi M-80 spectrometer, respectively. Volatile
products were quantified by GLC (methane (Porapak Q/FID);
benzene (Silicone SE-30/FID); H2 (molecular sieves 5A/TCD);
Hitachi gas chromatograph 163).
St a r t in g Ma t er ia ls. Diruthenium complexes Cp2Ru2-
(CO)4,21 1,4 and 1-d44 were prepared according to the literature
procedures. Most of the hydrosilanes and -stannanes were
purchased and used as received. HSiMe3, H2SiEt2, and
HSnMe3 were prepared by reduction of the corresponding
chlorosilanes and bromostannane with LiAlH4, and the deu-
teriosilane D2SiEt2 was prepared by treatment of Cl2SiEt2 with
LiAlD4. Diphenyldiazomethane was prepared by following the
literature procedure.22
to the dinuclear system (M2(µ-CH2)) (Scheme 7).20
A
CO ligand with such flexible coordinating ability leads
to stabilization of various structures compared to CH2,
which lacks flexibility in the coordination mode. As for
the latter point, the oxidative addition increases the
oxidation state of the Ru center up to +5 (7-10), which
is a rather unusual one in organoruthenium chemistry.
It is also found that treatment of 2 with alkynes and
diphenyldiazomethane induces C-C coupling, though
the expected multiple C-C coupling has not been
observed so far. The multiple C-C coupling is ham-
pered by transformation of the µ-CH2 functional group,
namely reductive elimination with an η1 ligand (in
particular, hydride arising from oxidative addition of
H-Si, H-Sn, H-H, and H-C bonds) leading to a
methyl group. The expected reaction may be realized
by designing a system which is not susceptible to
methylene-hydride reductive elimination.
(20) (a) Berke, H.; Hoffmann, R. J . Am. Chem. Soc. 1978, 100, 7224.
(b) Schilling, B. E. R.; Hoffmann, R.; Lichtenberger, D. L. J . Am. Chem.
Soc. 1979, 101, 585. (c) Kostic, N. M.; Fenske, R. F. J . Am. Chem. Soc.
1982, 104, 3879.
(21) Bruce, M. I.; J ensen, C. M.; J ones, N. L. Inorg. Synth. 1989,
26, 259.
(22) Smith, L. I.; Howard, K. L. Organic Syntheses; Wiley: New
York, 1995; Collect. Vol. III, p 351.

5582 Organometallics, Vol. 16, No. 25, 1997
Akita et al.
Syn th esis of Cp 2Ru 2(µ-CH2)2(CO)(NCMe) (2). Irradia-
tion of a saturated acetonitrile solution of 1 (ca. 2 mg/mL) with
slow argon bubbling resulted in a color change of the reaction
mixture from yellow to orange. The progress of the reaction
was monitored by IR spectroscopy. After irradiation for 6 h,
the acetonitrile complex 2 was obtained as yellow-orange
crystals in a quantitative yield by crystallization from aceto-
nitrile. 2: δH (C6D6) 8.86, 7.28 (2H × 2, s × 2, CH2 × 2), 4.90,
4.58 (5H × 2, s × 2, Cp2), 0.82 (3H, s, CH3CN); IR (CH3CN)
ν(CtO) 1909 cm-1. Anal. Calcd for C15H17NORu2: C, 41.91;
H, 3.96; N, 3.26. Found: C, 41.75; H, 3.80; N, 3.32.
δC (C6D6) 204.3 (s, CO), 150.6 (s, ipso), 133.6, 127.6, 127.3 (Ph
signals), 108.7 (t, J ) 141 Hz, µ-CH2), 86.7, 86.4 (d × 2, J )
176 Hz, Cp2), 17.6, 14.6, 6.7, 6.5 (q × 4, J ) 119 Hz, CH3); IR
(CH2Cl2) ν(CtO) 1932 cm-1. Anal. Calcd for C22H30ORu2Si2:
C, 46.41; H, 5.27. Found: C, 46.41; H, 4.72.
Rea ction of 2 w ith HSiP h 3. The reaction was carried out
under the same conditions as described above. 8f: δH (C6D6)
8.47 (1H, s, CH2) 7.89-7.03 (m, CH2 and Ph signals), 4.52,
4.17 (5H × 2, s × 2, Cp2), -13.25 (1H, s, RuH); δC (C6D6) 203.1
(s, CO), 151-128 (Ph signals: some of them are overlapped
with the C6D6 signals), 115.5 (t, J ) 140 Hz, µ-CH2), 90.2 (d,
J ) 178 Hz, Cp), 87.5 (d, J ) 178 Hz, Cp); IR (CH2Cl2) ν(CtO)
1928 cm-1. Anal. Calcd for C42H38ORu2Si2: C, 61.76; H, 4.65.
Found: C, 61.38; H, 4.38.
Rea ction of 2 w ith H2SiEt2. A mixture of 2 (80.5 mg, 0.18
mmol) and H2SiEt2 (73 µL, 0.56 mmol) was stirred at room
temperature overnight. After removal of the volatiles under
reduced pressure, the residue was subjected to preparative
TLC separation (silica gel, eluted with ether-hexane (1:10)).
From two yellow bands, the bis(µ-methylene)-hydrido complex
7a (30.0 mg, 0.063 mmol, 34% yield) and the µ-methylene-
µ-silylene-hydrido complex 8a (42.0 mg, 0.076 mmol, 41%
yield) were obtained. 7a : δH (C6D6) 8.05, 7.07 (2H × 2, s × 2,
CH2 × 2), 4.79, 4.67 (5H × 2, s × 2, Cp2), 3.25 (1H, m, SiH),
1.36-1.08 (10H, m, C2H5), -15.1 (1H, s, RuH); δC (C6D6) 202.8
(s, CO), 118.8 (t, J ) 141 Hz, µ-CH2), 86.3, 85.6 (d × 2, J )
178 Hz, Cp2), 13.2 (t, J ) 119 Hz, SiCH2), 10.6 (q, J ) 126 Hz,
Rea ction of 7a w ith H2SiEt2. A mixture of 7a (36.0 mg,
0.076 mmol) and H2SiEt2 (20 µL, 0.15 mmol) in benzene (1
mL) was stirred at room temperature for 48 h, during which
time 7a was converted to 8a in a nearly quantitative yield.
Rea ction of 2 w ith HSn Me3. To a suspension of 2 (68.0
mg, 0.16 mmol) in hexane (5 mL) was added HSnMe3 (60 µL,
0.5 mmol). The resultant mixture was stirred for 30 min at
room temperature. A yellow supernatant hexane solution was
obtained by centrifugation. The bis(µ-methylene)-hydrido-
stannyl complex 9a (72.3 mg, 0.13 mmol, 83% yield) was
obtained as a yellow precipitate by adding methanol to the
hexane solution. 9a : δH (C6D6) 8.25, 7.19 (2H × 2, s × 2, CH2
× 2), 4.69, 4.45 (5H × 2, s × 2, Cp2), 0.45 (9H, s, SnMe3,
CH3); IR (CH2Cl2) ν(CtO) 1920 cm-1
26ORu2Si: C, 42.85; H, 5.46. Found: C, 42.36; H, 5.49. 8a :
. Anal. Calcd for C17-
H
δH (C6D6) 8.03; 5.93 (1H × 2, d × 2, J ) 2.9 Hz, CH2), 4.64,
4.46 (5H × 2, s × 2, Cp2), 4.04 (1H, m, SiH), 1.46-1.02 (20H,
m, C2H5), -15.4 (1H, s, RuH); δC (C6D6) 203.8 (s, CO), 109.1
(t, J ) 140 Hz, µ-CH2), 86.0, 85.1 (d × 2, J ) 176 Hz, Cp2),
17.54 (t, J ) 119 Hz, SiCH2), 13.62 (t, J ) 121 Hz, SiCH2),
10.22 (q, J ) 126 Hz, CH3), 10.22 (q, J ) 125 Hz, CH3); IR
(CH2Cl2) ν(CtO) 1933 cm-1. Anal. Calcd for C20H34ORu2Si2:
C, 43.79; H, 6.20. Found: C, 44.04; H, 6.59.
Rea ction of 2 w ith H2SiP h 2. Stirring a mixture of 2 (83.0
mg, 0.19 mmol) and H2SiPh2 (110 µL, 0.6 mmol) in benzene (5
mL) for 48 h at room temperature afforded a yellow solution.
After removal of volatiles under reduced pressure, the yellow
µ-diphenylsilylene complex 8b (62.0 mg, 0.084 mmol, 43%
yield) was obtained by preparative TLC separation (silica gel,
eluted with ether-hexane (1:10)). 8b: δH (C6D6) 8.24 (1H, s,
CH2), 7.90-7.02 (m, Ph and CH2), 5.32 (1H, s, SiH), 4.55, 4.46
(5H × 2, s × 2, Cp2), -13.42 (1H, s, RuH); δC (C6D6) 202.9 (s,
CO), 149.5 (s, ipso), 148.0 (s, ipso), 135.7, 135.6, 128.9, 128.8,
127.6, 127.4 (Ph signals), 114.3 (t, J ) 147 Hz, µ-CH2), 89.4
(d, J ) 178 Hz, Cp), 87.5 (d, J ) 178 Hz, Cp); IR (CH2Cl2)
ν(CtO) 1928 cm-1. Anal. Calcd for C36H34ORu2Si2: C, 58.32;
H, 4.59. Found: C, 58.58; H, 4.21.
Rea ction of 2 w ith HSiMe3. A mixture of 2 (21.4 mg, 0.05
mmol) and HSiMe3 (30 µL, ca. 0.25 mmol) in benzene (0.5 mL)
was stirred for 15 min at room temperature. The formation
of the bis(µ-methylene)-hydrido-silyl complex 7c (58% yield),
which could not be isolated in pure form due to the thermal
instability, was confirmed by a 1H NMR spectrum of the
reaction mixture. 7c: δH (C6D6) 7.94, 6.00 (2H × 2, d × 2, J
) 3.0 Hz, CH2 × 2), 4.62, 4.45 (5H × 2, s × 2, Cp2), -15.4 (1H,
s, RuH).
Rea ction of 2 w ith HSiEt3. The reaction of 2 (13.7 mg,
0.032 mmol) with HSiEt3 (26 µL, 0.16 mmol) did not occur at
ambient temperature. Heating of this solution at 60 °C gave
a mixture of unidentified organometallic products along with
methane (95% yield), as revealed by GC analysis.
2
2J Sn-Ru-H ) 23 Hz), -13.68 (1H, s, RuH, J Sn-Ru-H ) 112 Hz);
δC (C6D6) 202.4 (s, CO), 106.9 (dd, J ) 137, 148 Hz, CH2), 88.2,
85.4 (d × 2, J ) 176 Hz, Cp), -3.16 (q, J ) 126 Hz, SnMe3);
IR (CH2Cl2) ν(CtO) 1936 cm-1. Anal. Calcd for C16H24ORu2-
Sn: C, 34.74; H, 4.34. Found: C, 34.71; H,4.54.
Rea ction of 2 w ith HSn P h 3. A mixture of 2 (64.7 mg,
0.15 mmol) and HSnPh3 (180.0 mg, 0.51 mmol) in benzene (3
mL) was stirred for 1 h at room temperature. After removal
of the solvent under reduced pressure, the residue was
subjected to preparative TLC separation (silica gel, eluted with
ether-hexane (1:10)). Two bands were collected. From the
higher band, the bis(µ-methylene)-hydrido-stannyl complex
9b (54.0 mg, 0.073 mmol, 48% yield) was obtained as yellow
crystals after recrystallization from ether-hexane. From the
lower band, the tristannyl complex 10 (35.0 mg, 0.024 mmol,
15% yield) was obtained as pale yellow crystals after recrys-
tallization from hot hexane. 9b: δH (C6D6) 8.67, 8.51 (2H ×
2, s × 2, CH2 × 2), 7.80-6.98 (m, Ph signals), 4.68, 4.37 (5H
× 2, s × 2, Cp2), -12.74 (1H, s, RuH); δC (C6D6) 202.6 (s, CO),
145-128 (Ph signals: some of them are overlapped with the
C6D6 signals), 111.5 (t, J ) 139 Hz, µ-CH2), 89.8 (d, J ) 178
Hz, Cp), 87.9 (d, J ) 178 Hz, Cp); IR (CH2Cl2) ν(CtO) 1930
cm-1
. Anal. Calcd for C31H30ORu2Sn: C, 50.32; H, 4.06.
Found: C, 49.59; H, 4.24. 10: δH (C6D6) 8.49, 7.58 (1H × 2, s
× 2, µ-CH2), 7.93-6.93 (m, Ph signals), 4.57, 4.49 (5H × 2, s
× 2, Cp2), -12.43 (1H, s, RuH); δC (C6D6) 200.5 (s, CO), 145.2
(s, ipso), 146-128 (Ph signals: some of them are overlapped
with the C6D6 signals), 107.7 (t, J ) 145 Hz, µ-CH2), 88.4 (d,
J ) 176 Hz, Cp), 86.0 (d, J ) 176 Hz, Cp); IR(CH2Cl2) ν(CtO)
1904 cm-1. Anal. Calcd for C66H59ORu2Sn3: C, 55.58; H, 4.14.
Found: C, 55.58; H, 4.02.
Rea ction of 2 w ith H
2. A benzene (20 mL) solution of 2
(30.2 mg, 0.07 mmol) in a glass autoclave under H2
(1 atm)
was stirred overnight at room temperature, and the black
precipitate 11 (22.6 mg, 0.03 mmol, 86% yield) appeared
gradually. Crystals of 11 were obtained by recrystallization
from a saturated CH2Cl2 solution at room temperature. 11:
δH (CDCl3) 15.0 (1H, s, µ3-CH), 5.31 (5H, s, Cp), 5.00 (10H, s,
Cp2), 4.78 (5H, s, Cp), -12.6 (1H, s, µ3-H); δC (CDCl3) 91.8,
Rea ction of 2 w ith HSiMe2P h . A mixture of 2 (55.0 mg,
0.13 mmol) and HSiMe2Ph (60 µL, 0.39 mmol) in benzene (3
mL) was stirred for 48 h at room temperature. After removal
of the volatiles, the µ-silylene complex 8e (53.0 mg. 0.093
mmol, 73% yield) was obtained by preparative TLC separation
(silica gel, eluted with ether-hexane (1:10)), and recrystalli-
zation from hexane afforded yellow crystals. 8e: δH (C6D6)
7.95, 6.22 (1H × 2, d × 2, J ) 2.9 Hz, CH2), 7.75-7.15 (m, Ph
signals), 4.65, 4.35 (5H × 2, s × 2, Cp2), 1.13, 0.62 (3H, s × 2,
µ-SiMe2), 0.91, 0.90 (3H, s × 2, SiMe2), -14.97 (1H, s, RuH);
88.2, 85.3 (d × 3, J ) 177 Hz, Cp); IR(KBr) ν(CtO) 1617 cm-1
.
FD-MS 734 (M+ for the 101Ru4 isotopomer). Anal. Calcd for
C
23H22O2Ru4: C, 37.60; H, 3.00. Found: C, 38.06; H, 3.21.
Rea ction of 2 w ith P h CtCH. Stirring a solution of 2
(42.0 mg, 0.098 mmol) and phenylacetylene (33.0 µL, 0.30
mmol) at room temperature for 15 min gave a red solution.

MeCN Adducts of Ru2 Bis(µ-methylene) Species
Organometallics, Vol. 16, No. 25, 1997 5583
Ta ble 8. Cr ysta llogr a p h ic Da ta
11‚1/4(CH2Cl2)‚
2
9b
10‚(1/2hexane)
1/4(H2O)
12a
14
16
formula
C15H17ONRu2 C31H30OSnRu2 C72H72OSn3Ru2 C23.5H23O2.25
Cl0.5Ru4
760.4
-
C21H20ORu2
C38H30ORu2 C17H20ORu2
fw
429.5
739.4
1511.6
490.5
704.8
426.5
recryst solvent
cryst syst
space group
a/Å
b/Å
c/Å
CH3CN
monoclinic
P21/c
12.330(4)
9.130(1)
13.213(3)
ether-hexanes hexanes
CH2Cl2
monoclinic
C2/c
36.10(2)
9.530(6)
30.05(2)
ether-hexanes methanol
THF-hexanes
monoclinic
C2/c
monoclinic
monoclinic
P21/a
monoclinic triclinic
C2/c
P21/a
P1h
43.404(8)
10.629(2)
18.486(2)
31.809(5)
18.779(3)
26.084(4)
8.114(3)
24.91(1)
17.458(9)
16.709(5)
19.871(7)
9.0074()
9.503(2)
10.981(1)
7.560(1)
94.71(1)
113.00(1)
87.16(1)
723.5(2)
2
R/deg
â/deg
100.77(2)
105.38(1)
123.76(1)
118.50(4)
90.46(3)
98.88(3)
γ/deg
V/Å3
1461.2(6)
2
1.95
20.2
5-50
2883
8222(3)
12
12954(3)
8
9084(19)
16
2.61
3527(4)
8
2954(3)
4
Z
d
calcd/g cm-3
1.79
1.55
1.85
1.58
1.96
20.7
5-55
3527
2665
252
µ/cm-1
20.1
16.4
26.9
16.8
10.5
2θ/deg
5-40
7927
2280
394
5-45
8973
3731
391
3-50
8721
5965
546
3-48
5880
3606
433
5-50
5727
2534
370
no. of data collected
no. of data with I > 3σ(I) 2206
no. of params refined
188
R
Rw
0.026
0.026
0.039
0.033
0.066
0.071
0.049
0.051
0.074
0.073
0.053
0.040
0.025
0.024
After removal of the volatiles under reduced pressure, the
residue was subjected to preparative TLC separation (silica
gel, eluted with ether-hexane (1:15)). A red-orange band was
collected, from which 12a (50.0 mg, 0.090 mmol, 92% yield)
was obtained as red-orange crystals after recrystallization from
ether-hexane. 12a : δH (CDCl3) 9.07, 8.32 (1H × 2, s × 2,
µ-CH2), 7.75-7.22 (5H, m, Ph), 4.87, 4.76 (5H × 2, s × 2, Cp2),
4.87 (1H, dd, J ) 6.4, 7.8 Hz, CH), 2.70 (1H, d, J ) 6.3, CH2),
-0.12 (1H, d, J ) 7.8 Hz, CH2); δC (CDCl3) 200.6 (s, CO), 175.7
(s, µ-C), 156.5 (s, ipso), 130.2 (t, J ) 146 Hz, µ-CH2), 128.4 (d,
J ) 157 Hz, Ph), 128.0 (d, J ) 150 Hz, Ph), 125.7 (d, J ) 159
Hz, Ph), 89.1 (d, J ) 176 Hz, Cp), 83.9 (d, J ) 184 Hz, Cp),
77.6 (d, J ) 156 Hz, CH), 43.3 (t, J ) 156 Hz, CH2); IR(CH2-
Cl2) ν(C≡O) 1921 cm-1. Anal. Calcd for C21H20ORu2: C, 51.37;
H, 4.08. Found: C, 51.69; H, 4.14.
separation (alumina, eluted with ether-hexane (1:15)). An
orange band was collected, from which 14 (38.0 mg, 0.054
mmol, 34% yield) was obtained after recrystallization from hot
methanol. The formation of methane (21% yield) was observed
by GLC analysis. δH (CDCl3) 7.94-6.53 (m, Ph), 4.35, 4.05
(5H × 2, s × 2, Cp2), 2.66 (1H, dd, J ) 5.8, 1.5 Hz, Ph); δC
(CDCl3) 253.6 (s, µ-C)CPh2), 205.8 (s, CO), 99.6 (s, µ-CPh2),
91.5 (d, J ) 178 Hz, Cp), 160-120 (Ph signals), 85.6 (d, J )
178 Hz, Cp), 72.9 (d, J ) 168 Hz, Ph); IR (CH2Cl2) ν(CtO)
1941 cm-1. Anal. Calcd for C38H30ORu2: C, 64.77; H, 4.26.
Found: C, 65.23; H,4.47.
F or m a tion of 3. 1H NMR Exp er im en t. A CD3CN solu-
tion (0.6 mL) of 1 (10.0 mg, 0.024 mmol; a mixture of cis and
trans isomers) was irradiated by a high-pressure mercury
lamp. Within 30 min complete isomerization to the cis isomer
was observed, and then 1 gradually converted to 2. Further
irradiation produced 3 as the sole product.
Rea ction of 2 w ith Me3SiCtCH. The reaction was
carried under the same conditions as described above. 12b
(79% yield): δH (CDCl3) 8.97, 8.42 (1H × 2, s × 2, µ-CH2), 4.65,
4.58 (5H × 2, s × 2, Cp2), 4.58 (1H, dd, J ) 4.7, 6.6 Hz, CH),
2.70 (1H, dd, J ) 6.6, 1.4 Hz, CH2), -0.12 (1H, dd, J ) 4.7,
1.0 Hz, CH2), 0.03 (9H, s, SiMe3); IR (CH2Cl2) ν(CtO) 1922
Rea ction of 3 w ith CNCy. An acetonitrile solution of 80
mL) of 1 (43.2 mg, 0.104 mmol) was irradiated by a high-
pressure mercury lamp for 30 h, while a slow Ar bubbling was
maintained. After the completion of the decarbonylation was
checked by IR, cyclohexyl isocyanide (130 µL, 1.05 mmol) was
added and the resulting mixture was stirred for 3 h at room
temperature. Removal of the volatiles and TLC separation
(silica gel; hexanes-ether (6:1)) gave 15 (30.2 mg, 0.052 mmol,
50% yield) as a yellow powder: δH (C6D6) 8.54 (2H, s, µ-CH2),
7.07 (2H, s, µ-CH2), 4.99 (10H, s, Cp2), 3.26 (2H, s, CNCH),
1.2-1.4 (12H, m, Cy), 1.2-1.0 (8H, m, Cy); δC (C6D6) 176.3 (s,
NC), 107.3 (dd, J ) 147 and 136 Hz, µ-CH2), 85.9 (d, 175 Hz,
Cp), 54.4 (d, J ) 142 Hz, CNCH), 34.7 (t, J ) 129 Hz, Cy),
25.6 (t, J ) 127 Hz, Cy), 23.3 (t, J ) 127 Hz, Cy); IR (CH2Cl2)
cm-1
.
Anal. Calcd for C18H24ORu2Si: C, 44.4; H, 4.94.
Found: C, 44.0; H, 5.08.
Rea ction of 2 w ith P h CtCP h . The reaction was carried
under the same conditions as described above. 12c (74% yield)
was characterized by comparison with the reported data.
Rea ction of 2 w ith Eth yl Acr yla te. A CH2Cl2 solution
(3 mL) of 2 (120 mg, 0.28 mmol) and ethyl acrylate (40 µL,
0.37 mmol) was stirred overnight at room temperature. After
removal of the volatiles under reduced pressure, 13 (76.5 mg,
0.16 mmol, 56% yield) was obtained by preparative TLC
separation (silica gel, eluted with CH2Cl2-hexane (1:1)). 13:
δH (CDCl3) 8.96, 8.75, 8.56, 8.43 (1H × 4, s × 4, µ-CH2 × 2),
5.07, 4.83 (5H × 2, s × 2, Cp2), 4.11 (2H, q, J ) 7.3 Hz, CH2-
CH3), 3.27 (1H, d, J ) 10.7 Hz, CH2dCH), 1.30 (3H, t, J ) 7.3
Hz, CH3), 1.16 (1H, dd, J ) 10.7, 7.8 Hz, CH2dCH), 0.91 (1H,
d, J ) 7.8 Hz, CH2dCH); δC (CDCl3) 202.2, (s, CO), 177.8 (s,
COO), 126.4 (t, J ) 145 Hz, µ-CH2), 123.5 (t, J ) 147 Hz,
µ-CH2), 90.3 (d, J ) 178 Hz, Cp), 88.6 (d, J ) 176 Hz, Cp),
59.4 (t, J ) 147 Hz, CH2CH3), 49.03 (d, J ) 160 Hz, CH), 42.6
(t, J ) 158 Hz, CH2d), 14.7 (q, J ) 127 Hz, CH2CH3); IR (CH2-
Cl2) ν(CtO) 1937, 1712 cm-1. Anal. Calcd for C18H22O3Ru2:
C, 44.26; H, 4.50. Found: C, 43.71; H, 4.45.
ν(NC) 2082, 2060 cm-1
. Anal. Calcd for C26H36N2Ru2: C,
53.96; H, 6.27; N, 4.84. Found: C, 53.64; H, 6.20; N, 4.86.
Treatment of an MeCN solution with CO gave Cp2Ru2(µ-
CH2)2(CO)2.
Rea ction of 3 w ith Cyclop en ta d ien e. An MeCN solution
of 3 was prepared from 1 (50.0 mg, 0.120 mmol) as described
above. Addition of cyclopentadiene (1 mL) followed by workup
as described above gave 16 (20.5 mg, 0.048 mmol, 40% yield)
as yellow crystals: δH (C6D6) 8.77 (1H, d, J ) 2.4 Hz, µ-CH2),
8.46 (1H, d, J ) 1.2 Hz, µ-CH2), 8.30 (1H, d, J ) 2.4 Hz, µ-CH2),
7.40 (1H, d, J ) 1.2 Hz, µ-CH2), 4.53 (10H, s, Cp2), 3.71 (2H,
d, J ) 5.4 Hz, CdCH), 2.65 (2H, dd, J ) 5.4 and 3.1 Hz,
CH2CHd), 2.50 (1H, d, J ) 16.4 Hz, CH2), 1.63 (1H, dt, J )
16.4 and 3.1 Hz, CH2); δC (C6D6) 144.0 (t, J ) 142 Hz, µ-CH2),
122.8 (dd, J ) 154 and 136 Hz, µ-CH2), 85.8 (d, J ) 177 Hz,
Cp), 55.5 (d, J ) 167 Hz, CH2CHdCH), 47.1 (d, J ) 160 Hz,
Rea ction of 2 w ith Dip h en yld ia zom eth a n e. Ph2CN2
(0.75 mmol; dissolved in 0.15 mL of CH2Cl2) was added to a
solution of 2 (63.2 mg, 0.15 mmol) in CH2Cl2 (2 mL), and the
reaction mixture was stirred for 30 min. After removal of the
volatiles, the residue was subjected to preparative TLC

5584 Organometallics, Vol. 16, No. 25, 1997
Akita et al.
CH2CHdCH), 27.7 (t, J ) 132 Hz, CH2). Anal. Calcd for
scan) was also made. Crystallographic data and the results
of refinements are summarized in Table 8.
C
15H20ORu2: C, 47.88; H, 4.73. Found: C, 47.78; H, 4.69.
The structures were solved by a combination of direct
methods (SAPI91 and MITHRIL87) and Fourier synthesis
(DIRDIF). Unless otherwise stated, non-hydrogen atoms were
refined with anisotropic thermal parameters, and hydrogen
atoms were fixed at calculated positions (C-H ) 0.95 Å) and
were not refined. Details of the structural analyses are as
follows. 2: the methylene hydrogen atoms (H1a,b and H2a,b)
Rea ction of 3 w ith Bu ta d ien e. An MeCN solution of 3
was prepared from 1 (55.3 mg, 0.133 mmol) as described above.
1,3-Butadiene was introduced into the system from a balloon.
Subsequent workup as described above gave an isomeric
mixture of 17 (19.3 mg, 0.046 mmol, 35% yield) as yellow
crystals. s-cis isomer: δH (C6D6) 8.92, 8.66, 8.65, 6.96 (1H ×
4, s × 4, µ-CH2), 4.51 (10H, s, Cp2), 3.56 (2H, m, CHd), 1.87
(2H, d, J ) 8.3 Hz, dCH2), 1.55 (2H, d, J ) 9.7 Hz, dCH2); δC
(C6D6) 132.4 (t, J ) 141 Hz, µ-CH2), 117.1 (dd, J ) 156 and
136 Hz, µ-CH2), 85.1 (d, J ) 176 Hz, Cp), 56.8 (d, J ) 160 Hz,
dCH), 37.5 (t, J ) 158 Hz, dCH2). s-trans isomer: δH (C6D6)
8.64, 6.77 (2H × 2, s × 2, µ-CH2), 4.51 (10H, s, Cp2), 2.92 (2H,
m, dCH), 2.38 (2H, d, J ) 9.8 Hz, dCH2), 2.32 (2H, d, J ) 5.6
Hz, dCH2); δC (C6D6) 126.4 (dd, J ) 145 and 136 Hz, µ-CH2),
84.7 (d, J ) 176 Hz, Cp), 63.0 (d, J ) 158 Hz, dCH), 46.3 (t,
J ) 154 Hz, dCH2). Anal. Calcd for C16H20ORu2: C, 46.37,
H, 4.86. Found: C, 46.14; H,4.45.
were refined isotropically. 9:
a unit cell contained two
independent molecules, and one of them (molecule 2: b series)
sits on a symmetrically imposed site. The non-hydrogen atoms
of molecule 1 (a series) was refined with anisotropic thermal
parameters. As for molecule 2, Sn1b, Ru1b, and Ru2b were
refined anisotropically, O3b and C1-3b were refined isotro-
pically, and the carbon atoms of the Cp and Ph parts were
refined using rigid-group models. 10: because of the limited
number of the data, the Ph groups and the hexane molecule
were refined isotropically. 11: a unit cell contained two
independent molecules. During the course of the refinement
it was found that the µ3 ligands were disordered. As for
molecule 1, the minor component was not included in the
refinement. As for molecule 2, the µ3-CH and µ3-CO ligands
were considerably disordered and the occupancies of the
oxygen atoms were refined as follows: O22, 0.757; O23, 0.724;
O24, 0.519. 14: All the hydrogen atoms were refined isotro-
pically.
X-r a y Cr ysta llogr a p h y. Suitable single crystals were
obtained from recrystallization from the solvent described in
Table 8 and mounted on glass fibers.
Diffraction measurement was made on Rigaku AFC-5R (2,
9-11, 14) and AFC-5S (12a ) automated four-circle diffracto-
meters by using graphite-monochromated Mo KR radiation (λ
) 0.710 59 Å). The unit cells were determined and refined by
a least-squares method using 20 independent reflections (2θ
≈ 20°). Data were collected by ω-2θ or ω scan techniques. If
σ(F)/F was more than 0.1, a scan was repeated up to three
times and the results were added to the first scan. Three
standard reflections were monitored every 150 measurements.
The data processing was performed on a Micro Vax II computer
(data collection) and IRIS Indigo and Indy computers (struc-
ture analysis) by using the teXsan structure solving program
system obtained from the Rigaku Corp., Tokyo, J apan. Neu-
tral scattering factors were obtained from the standard
source.23 In the reduction of data, Lorentz and polarization
corrections were made. An empirical absorption correction (Ψ
Ack n ow led gm en t. We are grateful to the Ministry
of Education, Science, Sports, and Culture of the
J apanese Government for financial support of this
research.
Su p p or tin g In for m a tion Ava ila ble: Tables of positional
parameters and Beq values, anisotropic thermal parameters,
and bond lengths and angles and figures giving atomic
numbering schemes for 9b (molecule 2), the carbon atoms of
the Ph and Cp groups and the hexane part of 10‚(1/2hexane),
(molecule 2), and the solvent parts of 11‚1/4(CH2Cl2)‚1/4(H2O),
and 12a (molecule 2) (48 pages). Ordering information is given
on any current masthead page.
(23) International Tables for X-Ray Crystallography; Kynoch
Press: Birmingham, U.K., 1975; Vol. 4.
OM9706727