Reactions of ruthenium vinylidene and acetylide complexes containing trichloromethyl groups: Preparation of a cyclobutenonyl complex by solid-state photolysis

Article abstract of DOI:10.1002/chem.200802133

New reactions were observed for the cationic γ-hydroxyvinylidene complex [Ru²]=C=CHC(OH)(CCl₃)₂+ (2, [Ru ²] = CpRu(PPh₃)₂). A rare chloroform elimination was observed when 2 was treated wit

Full text of DOI:10.1002/chem.200802133

FULL PAPER
DOI: 10.1002/chem.200802133
Reactions of Ruthenium Vinylidene and Acetylide Complexes Containing
Trichloromethyl Groups: Preparation of a Cyclobutenonyl Complex by Solid-
State Photolysis
Chung-Yeh Wu, Hsien-Hsin Chou, Ying-Chih Lin,* Yu Wang, and Yi-Hung Liu[a]
2
À ꢀ
Abstract: New reactions were observed
terms of Gibbs free energy than 3. In
the coupling reaction of 4 with 2-
methyl-1-buten-3-yne the four-mem-
bered cyclic ligand is transferred to the
enyne to give substituted h3-butadienyl
complex 5 containing a cyclobutenonyl
group. This coupling product could be
removed from the metal by HCl. De-
protonation of 2 gave g-hydroxyacety-
lide complex [Ru ] C CC(OH)
N
for the cationic g-hydroxyvinylidene
(9). In the photolysis of 9 phosphine
dissociation is followed by addition of
HCl to give neutral vinylidene complex
+
complex [Ru2]=C=CHC(OH)
ACHTNUTRGNEUG(N CCl3)2
(2, [Ru2]=CpRu
(PPh3)2).
A
rare
chloroform elimination was observed
Cl
[Ru1]=C=CHC(OH)
G
when 2 was treated with nBu4NOH to
[Ru1]=Cp
ACHTUNGTRENNUNG
2
À
give neutral acetylide complex [Ru ]
lyzed the coupling reaction of dimethyl
acetylenedicarboxylate with styrene
yielding the diene PhCH=CHC-
ꢀ
C CC(=O)CCl3 (3). Solid-state photo-
induced isomerization of 3 generated
ruthenium
perchlorocyclobutenonyl
À
G
Solid-state
2
complex [Ru ] C4Cl3O (4) in high
yield. This transformation was analyzed
by DFT calculations, and 4 was found
to be 4.22 kcalmolÀ1 more stable in
Keywords: cyclization · isomeriza-
tion · photochemistry · ruthenium ·
solid-state reactions
Introduction
have attracted increasing attention because of their utility as
building blocks or key intermediates in the synthesis of nat-
ural products.[3]
We previously reported the preparation of a number of
ruthenium cyclopropenyl complexes by deprotonation at Cg
of vinylidene ligands on the metal center (Scheme 1).[1] The
three-membered-ring ligand stabilized by the metal easily
opens when transferred to an organic moiety. Our attempts
to synthesize cyclobutenyl ligands by a similar strategy
failed to yield the desired products. However, when an ap-
propriate pending vinyl group is attached to the vinylidene
ligand a metathesis process between the two C=C double
bonds was observed (Scheme 1).[2] Even though metal com-
plexes containing four-membered cyclic ligands have been
much less studied, compounds with four-membered rings
Traditionally, most synthetic methods for carbocyclic four-
membered ring fragments utilize the [2+2] cycloaddition of
two unsaturated substrates in organic systems,[3] or cycload-
dition between a metal acetylide and an unsaturated organic
substrate in the case of inorganic complexes.[4,5] Owing to in-
herent ring strain, four-membered ring compounds easily
undergo ring-opening reactions to form various acyclic prod-
ucts, especially under thermolytic or photoinduced condi-
[a] C.-Y. Wu, H.-H. Chou, Prof. Dr. Y.-C. Lin, Y. Wang, Y.-H. Liu
Department of Chemistry
National Taiwan University
Taipei, 106 (Taiwan)
Fax : (+886) 223636359
E-mail: yclin@ntu.edu.tw
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/chem.200802133.
Scheme 1. Cyclopropenation and metathesis of ruthenium vinylidene
complexes.
Chem. Eur. J. 2009, 15, 3221 – 3229
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3221

tions.[3,5,6] Since the early work of Schmidt et al. in the
1970s,[7] photoinduced reactions in the solid state have been
applied in several fields,[8] such as crystal engineering, self-
assembly, supramolecular chemistry, and polymer chemistry.
Nowadays, investigations on photochemistry in the solid
state remains highly relevant.[9] Herein we report unusual
chemical reactivity of a ruthenium cyclobutenonyl complex,
prepared by solid-state photoisomerization. This complex
with a four-membered cyclic ligand is stable yet displays in-
teresting reactivity. It also serves as an efficient catalyst for
coupling of activated acetylenes with styrene.
Figure 1. Molecular structure of 3 (ORTEP). Phenyl groups except for
the C(ipso) atoms on the phosphorus ligands have been omitted for clari-
ty (thermal ellipsoid set at 50% probability). Selected bond lengths [ꢁ]
AHCTUNGTRENNUNG
Results and Discussion
À
À
À
À
and angles [8]: Ru1 C1 1.968(5), Ru1 P1 2.313(1), Ru1 P2 2.313(1), C1
À
À
À
C2 1.213(6), C2 C3 1.402(6), C3 C4 1.555(6), C3 O1 1.204(5); C1-C2-
C3 178.9(5), C2-C3-C4 114.1(4), O1-C3-C4 117.9(4), O1-C3-C2 128.1(5).
Treatment of [Ru2]Cl ([Ru2]=CpRu
CC(OH)
(PPh3)2) with HC
ꢀ
(CCl3)2, a propargylic alcohol bearing two trichloro-
methyl groups, in the presence of AgPF6 afforded cationic
+
2
g-hydroxyvinylidene complex [Ru2]=C=CHC(OH)
(CCl3)2
Ruthenium perchlorocyclobutenonyl complex [Ru ]
À
(2) in good yield with no allenylidene complex detected. It
is known that the reaction of a propargylic alcohol with a
metal halide generally yields an allenylidene complex by a
facile dehydration process.[10] The hydroxyvinylidene inter-
mediate can be isolated if the metal moiety is more electron
rich,[11] and in a few cases the hydroxyvinylidene complex
was observed as a mixture with the corresponding allenyli-
dene complex in NMR spectra.[12] However, our attempts to
induce dehydration of 2 failed to give the allenylidene com-
plex. Hydroxylvinylidene complex 2, possibly stabilized by
the presence of two trichloromethyl groups, exhibits novel
reactivity.
C4Cl3O (4) was then prepared from 3 by solid-state photoin-
duced isomerization in high yield (Scheme 2). When the
Addition of 1.1 equivalents of nBu4NOH to 2 in the ab-
sence of light caused deprotonation along with an unusual
intramolecular elimination of a chloroform molecule, and
Scheme 2. Synthesis of cyclobutenonyl complex 4.
2
À ꢀ
ruthenium trichloroacetyl acetylide complex [Ru ] C CC-
(=O)CCl3 (3) was isolated in good yield. In this reaction, the
chloroform dissociated from 2 was detected by 1H NMR
spectroscopy. The rare base-induced elimination of chloro-
form has been used for the synthesis of sulfines from allylic
and benzylic trichloromethyl sulfoxides.[13]
photolysis of 3 was carried out in C6D6 with 365 nm light
complex 4 was obtained as a minor product and [Ru2]Cl as
the major product. Formation of [Ru2]Cl increased in
CD2Cl2 or CDCl3. Although we implemented this photore-
action in other nonchlorinated solvents such as n-hexane
and benzene at low temperature, generation of [Ru2]Cl as
the major product was unavoidable. Only when the photoir-
radiation process was carried out in the solid state did a
clean reaction give 4 as the major product in 75% yield
with only a trace of [Ru2]Cl. The 31P NMR spectrum of 4 in
C6D6 displays a singlet at d=48.5 ppm. The mass spectrum
of 4 displays the same parent peaks as that of 3. The
1H NMR spectrum reveals only resonances attributed to Cp
and PPh3 ligands. These data provide no clue to the struc-
ture of this product. Therefore, single crystals of 4 were
grown from a CH2Cl2/n-hexane solution at À208C, and the
crystal structure determined by an X-ray diffraction study.
As shown in Figure 2, the perchlorocyclobutenonyl group is
Yellow, rodlike crystals of 3 were grown from CH2Cl2/n-
hexane solution at À208C and subjected to a single-crystal
X-ray diffraction study. The geometry around the Ru atom
in
3 can be described as a three-legged piano-stool
(Figure 1). The acetylide ligand is oriented such that the Cp
ring and the trichloromethyl group are located on the same
side relative to the linear Ru-C1-C2-C3 unit, and the car-
bonyl group and two PPh3 ligands are on the other side. On
2
[14]
À ꢀ
the contrary, in [Ru ] C CC(=O)Me,
the acetyl methyl
group and two phosphine ligands are on the same side, pos-
sibly due to lower steric repulsion between the methyl and
phosphine groups. The Ru-C1-C2 angle of 174.2(4)8 is essen-
[15]
À
tially linear and the Ru C1 bond length is 1.968(5) ꢁ.
À
The C3 O1 distance of 1.204(5) ꢁ is well within the range
of values reported for C=O double bonds. Similar bond
lengths and bond angles are observed for [Ru ]C CC-
À
s-coordinated to the metal center in 4. The Ru C1 distance
of 2.046(2) ꢁ is within the range of values reported for
2
ꢀ
À
À
( O)Me.
other Ru C single bonds. The four-membered ring of the
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Ruthenium Vinylidene and Acetylide Complexes
FULL PAPER
bitals of 3’ reveals that the LUMOs exhibit considerable or-
bital contribution located in the region of the trichlorometh-
yl moiety (see Figure S1 in the Supporting Information).
This leads to the reasonable expectation that photoexcita-
[18]
À
tion causes C Cl cleavage
giving chlorine and acetylide
(PPh3)2Cl]
radicals, and fits in with the observation of [CpRu
U
as the major product when photolysis was carried out in so-
lution. Effective inhibition of the isomerization of 3 to 4 was
observed on addition of galvinoxyl radical. Two hypothetical
paths are suggested (Scheme 3). Both start from acetylide
Figure 2. Molecular structure of 4 (ORTEP). Phenyl groups except for
the C
ACHTUNGTRENNUNG(ipso) atoms on the phosphorus ligands have been omitted for clari-
ty (thermal ellipsoid set at 50% probability). Selected bond lengths [ꢁ]
À
À
À
and angles [8]: Ru1 C1 2.046(2), Ru1 P1 2.3531(6), Ru1 P2 2.3723(6),
À
À
À
À
À
C1 C2 1.389(3), C2 C3 1.429(4), C3 C4 1.521(4), C1 C4 1.568(3), C3
O1 1.214(4); C1-C2-C3 99.00(2), C2-C3-C4 86.70(2), C3-C4-C1 87.83(2),
C4-C1-C2 86.27(2).
cyclobutenonyl moiety is nearly planar with the CCl2 group
in close proximity to the Cp ligand, possibly owing to the
3
À
less steric hindrance. The two C Cl bond lengths of the sp
carbon atom (1.778(3) and 1.787(3) ꢁ) are slightly longer
than the C Cl bond length of the sp2 carbon atom
À
À
(1.7191(3) ꢁ). The two Ru P bond lengths in complex 4
(2.3531(6) and 2.3723(6) ꢁ) are significantly longer than in
other complexes containing CpRuACHTNUTRGNEUNG(PPh3)2 fragments report-
ed in the literature.[16] This prompted to attempt a catalytic
reaction using 4 (see below).
To elucidate the mechanism of this unusual intramolecu-
lar transformation, we carried out a series of gas-phase den-
sity functional calculations at the B3LYP level using the
Gaussian 03 program suite.[17] Full-molecule ground-state
calculations show that the Gibbs free energy of complex 4 is
lower than that of 3 by 4.22 kcalmolÀ1, that is, transforma-
tion of 3 to 4 is a thermodynamically favorable process.
Even though the reaction was carried out in the solid state,
we believe the relative energies obtained by DFT are rele-
vant.
Scheme 3. Calculated potential energy surfaces of the two paths; values
in parentheses are in units of relative electronic energy.
À
À
For 4 the calculated Ru Ca distance of 2.05 ꢁ and C O
distance of 1.21 ꢁ are consistent with those obtained from
radical A1 and a chlorine radical. The initial radical A1 has
the acetylide structure, in which the C(O)CCl2 plane is per-
pendicular to the Cp plane. On path A, direct cyclization of
A1 gives A3, in which the cyclobutenonyl plane is parallel
to the Cp plane (Scheme 3a), as local minimum. Rotation of
the former plane for better overlap between the dp orbital
of the metal and p orbitals of Ca gives new local minimum
A4 on the potential-energy surface, in which the plane of
the four-membered ring is perpendicular to the Cp plane.[19]
Addition of a chlorine radical to A4 finally gives the prod-
uct. The local minimum A4 is slightly lower in free energy
than A3, by 1.58 kcalmolÀ1. However, the rearrangement of
A1 to A4 through path A is endothermic by 12.56 kcal
molÀ1, and transition structure A2 lies significantly higher
(31.06 kcalmolÀ1) in Gibbs free energy than A1. According-
ly, transformation via path B was examined (Scheme 3b).
À
the diffraction data, even though the Ru P distances of 2.54
3
À
and 2.51 ꢁ and the two C
(sp ) Cl bonds of 1.87 and 1.87 ꢁ
are slightly longer than the experimentally observed data.
To better understand the reaction path, a simplified
model in which two PPh3 groups are replaced by PH3
groups was used to search for the potential-energy surface
for the transformation. The calculated free energy of model
compound [CpACHTUNGTRENNUNG(PH3)2RuC4Cl3O] (4’) is lower than that of
À ꢀ
the model compound [Cp
A
ACHTUNGRTENN(UNG CCl3)] (3’)
by 17.56 kcalmolÀ1. Compared with the energy difference of
4.22 kcalmolÀ1 obtained from the full-molecule calculations,
it is clear that Ph groups on phosphine ligands play a role in
stabilization of the compounds. The simplified model system
is believed to provide satisfactory information on the mech-
anism of this transformation. Examination of the frontier or-
À
Interaction of the C C triple bond in radical A1 with the
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3223

Y.-C. Lin et al.
chlorine radical gives van der Waals complex B1.[20] Interest-
ingly, formation of the vinylidene intermediate by bonding
olefinic part of the enyne is accompanied by insertion of the
À
triple bond into the original Ru C bond. This reaction indi-
C
C
of Cl with Cb leading to [Cp
N
cates high stability of the metal-coordinated four-membered
cyclic ligand. The 1D and 2D NMR data of 5 are consistent
with the presence of the h3-butadienyl ligand.[21,22a] The
1H NMR spectrum of complex 5 shows a doublet at d=
is believed to be less likely than generation of van der
Waals complex B1, for the former is apparently 133.90 kcal
molÀ1 higher in Gibbs free energy than B1. Alternatively,
À
approaching the Cb Cl bond causes simultaneous formation
1.58 ppm with a coupling constant JACTHNGUTERNNU(G P,H) of 14.6 Hz, as-
À
of the Ca Cd bond to directly give cyclobutenonyl product
signed to the unique anti-proton Ha, and a singlet at d=
3.00 ppm, assigned to the syn-proton Hs. The 13C resonance
of the olefinic carbon atom C5 (see Scheme 4) of the ex-
tended h3-butadienyl ligand appears at d=108.12 ppm with
B3 on the potential-energy surface. Likewise, rotation of the
plane of the cyclobutenonyl ring further gives B4, in which
the aforementioned plane becomes perpendicular to the
plane of the Cp ligand. The process from B1 to B4 is exo-
thermic by 15.58 kcalmolÀ1, and the activation barrier for
the diradical transition structure B2 is 10.57 kcalmolÀ1 in
terms of Gibbs free energy. Consequently, the results show
that proposed path B is thermodynamically preferred. In
other words, the photoinduced cyclization process of com-
plex 3 could be reasonably rationalized by dissociation of a
chlorine radical on photoexcitation. Subsequent addition of
the chlorine radical to the resulting acetylide radical is fol-
a JACTHUNRTGNE(GNU P,C) of 6.75 Hz. In the 2D HMBC NMR spectrum, the
relatively downfield peak at d=218.7 assigned to C3 dis-
plays correlations with resonances of Ha, Hs, and CH3.
Further identification of complex 5 was achieved by
single-crystal structure determination on red, hexagonal
crystals of 5 grown from CH2Cl2/n-hexane solution at
À208C (Figure 3). The h3-allylic part of the butadienyl
À
lowed by C C bond formation to give cyclic product 4.
Reactions carried out in the solid state are of fundamental
interest in synthetic and materials chemistry because of the
remarkably high selectivity under the constraints of the crys-
tal lattice.[8] This technique was the subject of a number of
recent reports.[9] Our system is the first example of solid-
state photolysis of a metal acetylide complex that yields a
metal complex of four-membered cyclic ligand by a cycliza-
tion process. According to our calculations, the radical
formed by photolysis in the solid state is much less mobile
than that in solution, and hence the radical intermediate fol-
lows a new and different pathway giving the novel product.
In the solid state the rearrangement of the intermediate
could be caused by thermal energy to give an appropriate
orientation of reactive functional groups leading to the final
product, as shown by our calculations. The [2+2] cycloaddi-
tion of an activated double or triple bond to a metal acety-
lide complex is known to afford complexes with a four-
membered cyclic ligand.[4,5a] However, our synthetic strategy
is different from that reported in the literature.
Figure 3. Molecular structure of 5 (ORTEP). Phenyl groups except for
the C
ACHTUNGERTN(NUNG ipso) atoms on the phosphorus ligands have been omitted for clari-
ty (thermal ellipsoids set at 50% probability). Selected bond lengths [ꢁ]
À
À
À
and angles [8]: Ru1 C1 2.195(3), Ru1 C2 2.150(3), Ru1 C3 1.989(3),
À
À
À
À
Ru1 P1 2.3125(7), C1 C2 1.422(4), C2 C3 1.416(4), C3 C5 1.361(4),
À
À
À
À
À
C2 C4 1.517(4), C5 C6 1.404(4), C6 C7 1.382(4), C6 C9 1.501(4), C7
À
À
À
À
C8 1.439(5), C8 C9 1.528(4), C8 O1 1.205(4), C7 Cl1 1.699(3), C9 Cl2
À
1.766(3), C9 Cl3 1.797(3); C1-C2-C3 116.2(2), C6-C7-C8 95.4(3), C7-C8-
C9 87.1(2), C8-C9-C6 87.1(2), C9-C6-C7 90.4(2).
Reaction of 4 with 2-methyl-1-buten-3-yne at 708C exclu-
sively gave h3-butadienyl complex 5, in which the four-mem-
bered ring is bound to the h3-butadienyl ligand (see
Scheme 4). Displacement of the phosphine ligand by the
ligand in 5 adopts an exo configuration and is bonded to the
Ru atom through C1, C2, and C3, while C5 is bent away
À
from the ruthenium atom at a nonbonding Ru C distance
of 3.198(3) ꢁ. The C1-C2-C3 angle of 116.2(2)8 is compara-
ble to those of other analogous complexes.[22] The Ru C3
À
À
(1.989(3) ꢁ) distance is shorter than the Ru C2
[22]
À
(2.150(3) ꢁ) and Ru C1 (2.195(3) ꢁ) distances
due to
À
nonsymmetrical bonding of the butadienyl ligand. The C3
C5 distance of 1.361(4) ꢁ is comparable to the terminal C=
C distances of other h3-butadienyl complexes.[22] Delocaliza-
tion of the p electrons on the h3-allylic part of the butadien-
À
À
yl ligand is reflected in similar C1 C2 (1.422(4) ꢁ) and C2
C3 (1.416(4) ꢁ) bond lengths. The four-membered ring frag-
ment in complex 5 is again approximately planar with com-
parable bond lengths and angles to those in complex 4.
Scheme 4. Various products with four-membered rings from reactions of
4.
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Ruthenium Vinylidene and Acetylide Complexes
FULL PAPER
In THF/H2O (1/10), hydrolysis of the CCl2 group[23] of 4
lene, this could be followed by ketenophilic acetylene addi-
tion to afford substituted aromatic compounds. This annula-
tion approach has been applied to several organic reactions,
especially for the syntheses of natural products.[3,6b,25] How-
ever, for our cyclobutenone complexes, the ring-opening
process is not observed even at higher temperature or under
photoirradiation in the presence of dienophiles such as tet-
racyanoethylene (TCNE) and dimethyl acetylenedicarboxy-
late (DMAD). The metal-coordinated cyclobutenonyl frag-
ments are robust. Treatment of 5 with HCl[26] afforded
metal-free compound 7, a substituted cyclobutenone, as a
potential four-membered ring precursor for organic synthe-
sis. In the reaction of 4 with TCNE, TCNE substituted a
phosphine ligand to form deep blue complex 8 (Scheme 4).
Among the complexes reported here only 4 underwent a
substitution reaction with TCNE.[27]
À
yields cyclobutenedionyl ruthenium complex [Ru] C4ClO2
(6). Complex 6 is stable at 708C in aqueous solution. The
mass spectrum of 6 displays parent peaks and fragmentation
peaks of [MÀCp]+ and [MÀC4ClO2]+. The characteristic
peaks of the two carbonyl carbon atoms in the 13C NMR
spectrum appear as singlets at d=196.4 and 196.5 ppm. In
the IR spectrum of 6 absorptions at 1721.2 and 1746.8 cmÀ1
are assigned to two CO stretching bands (cf. 1751.3 cmÀ1 for
4). A single-crystal X-ray diffraction study was carried out
to determine the structure of 6. Yellow crystals of 6 were
grown by slow diffusion of n-hexane into a solution of 6 in
CH2Cl2 at room temperature.
Complex 6 has a piano-stool structure in which the Cp-
ACHTUNGTRENNUNG(PPh3)2Ru moiety bears a 2-chlorocyclobut-1-ene-3,4-dionyl
À
group, (Figure 4). The Ru C1 bond length of 2.002(4) ꢁ is
Surprisingly, when complex 2 was passed through a
column packed with Al2O3 (see Scheme 5)[28] acetylide com-
plex 9 with a hydroxyl group at Cg was obtained by a depro-
Figure 4. Molecular structure of 6 (ORTEP). Phenyl groups except for
the C
ACHTUNGTRENNUNG(ipso) atoms on the phosphorus ligands have been omitted for clari-
ty (thermal ellipsoids set at 50% probability). Selected bond lengths [ꢁ]
Scheme 5. Synthesis of neutral hydroxyvinylidene complex 10.
À
À
À
À
and angles [8]: Ru1 C1 2.002(4), Ru1 P1 2.323(1), Ru1 P2 2.340(1), C1
À
À
À
À
C2 1.412(5), C2 C3 1.435(6), C3 C4 1.554(6), C1 C4 1.557(6), C3 O2
À
1.218(5); C4 O1 1.234(6), C1-C2-C3 99.00(2), C2-C3-C4 86.70(2), C3-C4-
C1 87.83(2), C4-C1-C2 86.27(2).
tonation reaction. The reverse reaction of complex 9 to
complex 2 readily occurred on addition of HBF4.
À
comparable to the Ru C single-bond length found in 4.
Addition of an excess of nBu4NOH in MeOH to 9 first
led to 3, detected by NMR spectroscopy, possibly via the
same chloroform elimination step as in the transformation
of 2 into 3. This is followed by addition of a methoxyl group
at Cg yielding acetylide complex 11 (see Scheme 5). This
latter step is similar to the haloform reaction, in which a tri-
chloroacetyl group reacts with base in the presence of alco-
hol to afford an ester group.
Both Ru C
(sp2) single bonds of 4 and 6 are longer than the
À
À
À
Ru C(sp) bond of acetylide complex 3. The C1 C2 double
bond (1.412(5) ꢁ) of 6 is slightly longer than the corre-
sponding C1 C2 bond (1.389(3) ꢁ) in 4 and the C6 C7
bond (1.382(4) ꢁ) in 5 and is significantly longer than a reg-
À
À
À
ular double bond length. In 6, the C Cl bond length of
1.660(5) ꢁ is shorter than that to the sp2 carbon atom of 4
(1.719(3) ꢁ). Two carbonyl groups of the cyclobutenedionyl
moiety are oriented away from the Cp ligand. The two C=O
bond lengths of 1.218(5) and 1.234(6) ꢁ of the four-mem-
bered ring are comparable with those in 4 and 5.
Unlike the photoisomerization of 3 yielding 4, irradiation
of 9 in chloroform caused phosphine dissociation and afford-
ed neutral complex Cl
[Ru1]=C=CHC(OH)
ACHUTNGTRENNUG AHCUTNGTREN(NUGN CCl3)2 (10,
[Ru1]=Cp(PPh3)Ru) as the major product and [Ru2]Cl as
AHCTUNGTRENNUNG
In metal complexes containing a s-cyclobutenyl ring, con-
version of the four-membered cyclobutenyl ligand to the s-
butadienyl ligand can occur readily, especially in complexes
with electron-withdrawing groups such as CN or CF3 on the
four-membered ring. Such ring-opening reactions are also
familiar in organic cyclobutenone fragments and lead to the
formation of vinylketene.[6b,23a,24] In the presence of acety-
the minor product. The net reaction for the formation of 10
is dissociation of a phosphine ligand and addition of HCl to
9. The photolytic reaction in the presence of HCl gave
higher yield of 10. Complex 9 with an acetylide fragment
bearing two CCl3 groups at Cg could not undergo intramo-
lecular cyclization under irradiation. Surprisingly, no dehy-
dration took place at room temperature for both complexes
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Y.-C. Lin et al.
2 and 10. At 808C, complexes 2 and 10 decomposed to give
[Ru2]CO+ and [Ru1]ClCO, respectively.
Red, square single crystals of complex 10 were grown
from CH2Cl2/n-hexane solution at À208C, and the structure
of 10 was determined by single-crystal X-ray crystallography
(Figure 5). Complex 10 also adopts a piano-stool geometry
Scheme 6. Coupling of activated alkynes and styrene catalyzed by 4 and
possible mechanism.
Table 1. Alkene–alkyne coupling by complex 4 at 708C.
Entry
EC=CE
Olefin
Ratio[a]
(ester/olefin)
Time
[h]
Product
Yield
[%][b]
1
2
DMAD
DEAD
styrene
styrene
1:20
1:20
5
5
12a
12b
52
51
[a] Catalyst loading: 5 mol%. [b] Yields of isolated products based on
DMAD or DEAD.
Figure 5. Molecular structure of 10 (ORTEP). Phenyl groups except for
the C
ACHTUNGTRENNUNG(ipso) atoms on the phosphorus ligands have been omitted for clari-
ty (thermal ellipsoids set at 50% probability). Selected bond lengths [ꢁ]
À
À
À
À
and angles [8]: Ru1 C1 1.814(2), Ru1 P1 2.3152(6), C1 C2 1.305(3), C2
À
À
À
C3 1.514(3), C3 C4 1.585(3), C3 C5 1.588(3), C3 O1 1.391(2); Ru1-C1-
C2 171.8(1), C1-C2-C3 120.0(1).
reaction with 2-methyl-1-buten-3-yne or TCNE was ob-
served for complexes 3, 6, and 9, all of which have stable
À
Ru P bonds.
with PPh3, Cl, and the vinylidene as the three legs. The Ru=
C distance of 1.814(2) ꢁ is similar to Ru=C distances report-
ed for other vinylidene complexes. The Ru-C1-C2 bond
Conclusion
3
À
angle is 171.8(1)8 and the six C
range from 1.750(3) to 1.770(2) ꢁ, are slightly shorter than
G
Hydroxyvinylidene complex 2 undergoes chloroform elimi-
nation to give acetylide complex 3 bearing a COCCl3 group
at Cb. We developed a synthetic method using solid-state
photoinduced isomerization of 3 to give a high yield of
ruthenium perchlorocyclobutenonyl complex 4. The trans-
formation from 3 to 4 was analyzed by DFT calculations,
and 4 was found to be 4.22 kcalmolÀ1 more stable than 3.
The four-membered cyclic ligand in 4, stabilized by the Ru
center, is fairly robust, as indicated by its integrity in many
reactions of 4. Transfer of the intact ligand is observed in
the reaction of 4 with an enyne giving h3-butadienyl complex
5. Hydrolysis of 4 yielded the cyclobutenedionyl complex 6.
Coupling reactions of DMAD and DEAD with styrene
were efficiently catalyzed by 4 in the presence of excess sty-
rene to give diene products. Structures of five chlorine-rich
complexes were determined by single-crystal X-ray diffrac-
tion studies.
À
the two C Cl bond lengths of the cyclic sp carbon atom in
4 (1.778(2) and 1.787(1) ꢁ). The shorter C O distance of
1.391(3) ꢁ in the C(OH)
(CCl3)2 moiety is consistent with
the difficult dehydration process in 10. This underlying prin-
ciple may be the reason for the inability to dehydrate com-
plex 2.
A few half-sandwich complexes [CpRuACTHNUTRGNE(NUG cod)X] (cod=1,5-
cyclooctadiene; X=Cl, Br) have been used as precatalysts
for catalytic reactions,[29] mediated by the CpRuX fragment
after initial dissociation of the labile COD ligand. As de-
À
scribed above, 4 has significantly longer Ru P bond lengths
(2.353 and 2.372 ꢁ) than similar complexes with the Cp-
ACHTUNGTRENNUNG(PPh3)2Ru fragment. We therefore carried out the intermo-
lecular coupling of styrene and the activated alkynes[30]
DMAD and diethyl acetylenedicarboxylate (DEAD) cata-
lyzed by 4 at 708C to give 1,3-dienes 12a and 12b, respec-
tively (Scheme 6). Table 1 lists conditions and results of
these catalytic reactions. Configurations of 12a and 12b
Experimental Section
1
were determined by NMR spectroscopy. The H NMR spec-
trum of 12a shows a doublet at d=6.94 and 6.43 ppm in
C6D6 with a JACHTUNGTRENNUNG(H,H) coupling constant of 16.3 Hz, assigned
to the E configuration. Other complexes reported in this
paper are not able to catalyze such a reaction, possibly be-
cause of stronger binding of the phosphine ligand. With its
General procedures: Manipulations were performed under an atmos-
phere of dry nitrogen by using vacuum-line and standard Schlenk tech-
niques. Solvents were dried by standard methods and distilled under ni-
trogen before use. All reagents were obtained from commercial suppliers.
Dimethyl acetylenedicarboxylate (DMAD) and diethyl acetylenedicar-
boxylate (DEAD) were dissolved in C6H6, washed with NaHCO3 and
H2O, dried over Na2SO4, filtered, evaporated and distilled in vacuum.
Styrene was dried for several hours with MgSO4 and distilled at 258C
À
weaker Ru P bond, 4 could also be converted to complexes
5 and 8 by substitution of one PPh3 ligand. No substitution
3226
www.chemeurj.org
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 3221 – 3229

Ruthenium Vinylidene and Acetylide Complexes
FULL PAPER
under reduced pressure. The complex [CpRu
(PPh3)2Cl] was prepared by
washed with n-hexane (3ꢂ5 mL), and dried under vacuum to afford 6 as
a yellowish powder (0.42 g, 71.2%). 1H NMR (400 MHz, C6D6, 258C,
TMS): d=7.26–6.87 (m, 30H; Ph), 4.55 ppm (s, 5H; Cp); 13C{1H} NMR
(125 MHz, C6D6, 258C): d=196.4, 192.5 (CO), 127.7–137.9 (Ph, Ca and
CCl), 86.60 ppm (Cp); 31P{1H} NMR (162 MHz, C6D6, 258C): d=
49.46 ppm; MS (FAB+): m/z: 806.1; IR (Nujol): n˜CO =1721.2 (s),
1746.8 cmÀ1 (s); elemental analysis calcd (%) for C45H35ClO2P2Ru: C
67.04, H 4.38; found: C 67.20, H, 4.51.
corded on
a
Bruker AVANCE 400 instrument at 400 MHz (1H),
162.0 MHz (31P), or 100.6 MHz (13C) with SiMe4 or 85% H3PO4 as stan-
dard or on an Avance 500 FT NMR spectrometer.
7: A drop of 1m HCl in H2O was added to 5 (0.50 g, 0.75 mmol) in C6H6
at room temperature under N2. After stirring for 5 min, the mixture was
purified by flash column chromatography on silica gel (hexane/diethyl
ether 5/1, Rf =0.75). The solvent was removed at 108C under vacuum to
afford 7 as a yellow oil (0.09 g, 50.0%). 1H NMR (400 MHz, CDCl3,
2: In the absent of light, a solution of 1 (0.65 g, 0.22 mol) in CH2Cl2
(10 mL) was added to a mixture of [CpRuACHTNUTRGNEUNG(PPh3)2Cl] (1.63 g, 0.22 mmol)
and AgPF6 (0.57 g, 0.22 mmol) in CH2Cl2 (20 mL) at room temperature
under N2. After stirring for 4.5 h, the solution was filtered through a sin-
tered glass with Celite. The filtrate was concentrated to 4 mL and added
dropwise to n-hexane (60 mL) to precipitate a yellowish brown solid. The
precipitate was collected, washed with n-hexane (3ꢂ10 mL) and dried
under vacuum to afford 2 as a yellowish brown powder (0.97 g, 96.2%).
1H NMR (400 MHz, CDCl3, 258C, TMS): d=7.64–7.10 (m, 30H; Ph),
258C, TMS): d=7.46 (d, 3J
3J
(H,H)=16.1 Hz, 1H; CHCCCl), 5.60 (m, 2H; CH2), 2.0 ppm (m , 3H;
ACHTUNGTERN(NNUG H,H)=16.1 Hz, 1H; CH3CCHCH), 6.40 (d,
AHCTUNGTRENNUNG
CH3); 13C{1H} NMR (125 MHz, CDCl3, 258C): d=175.9 (CO), 175.1,
170.2 (CCl and CHCCCl), 149.5 (CH3CCHCH), 141.3 (CH3C), 128.6
(CH2), 112.0 (CHCCCl), 87.9 (CCl2), 17.6 ppm (CH3); EIMS: m/z: 235.96
[M+] 201.0 [M+ÀCl], 172.8 [M+ÀCOCl], 102.0 [M+ÀCOCl3]; elemental
analysis calcd (%) for C9H7Cl3O: C 45.51, H 2.97; found: C 45.29, H 3.15.
5.17 (s, 5H; Cp), 4.77 ppm (s, 1H; =CH); 13C{1H} NMR (125 MHz,
2
CDCl3, 258C): d=346.7 (t, J
G
(Cb), 104.3 (Cg), 95.4 (Cp), 90.7 ppm (CCl3); 31P{1H} NMR (162 MHz,
C6D6, 258C): d=41.91 ppm; MS (FAB+): m/z: 920.0 [M+]; elemental
analysis calcd (%) for C46H37Cl6F6OP3Ru: C 49.05, H 3.31; found: C
48.91, H, 3.42.
8: Tetracyanoethylene (0.04 g, 0.32 mmol) was added to a solution of 4
(0.25 g, 0.29 mmol) in C6H6 (30 mL) at room temperature and the mix-
ture heated to 708C for 5 h. The solvent was removed by rotary evapora-
tor and the residue dissolved in CH2Cl2 (5 mL), followed by adding the
solution to n-hexane (50 mL) to precipitate a blue solid. The precipitate
was collected, washed with n-hexane (3ꢂ5 mL), and dried under vacuum
to afford 8 as a blue powder (0.14 g, 67.1%). 1H NMR (400 MHz, C6D6,
258C, TMS): d=7.40–6.88 (m, 15H; Ph), 4.68 ppm (s, 5H; Cp); 13C{1H}
NMR (125 MHz, CDCl3, 258C): d=138.2–115.3 (Ph, Ca, CCl, and CN),
107.7 (CCl2), 86.0 ppm (Cp), (CO and C(CN)2 were not found); 31P{1H}
NMR (162 MHz, C6D6, 258C): d=50.90 ppm; MS (FAB+): m/z: 725.95;
elemental analysis calcd (%) for C33H20Cl3N4OPRu: C 54.52, H 2.77;
found: C 54.62, H 2.88.
Synthesis of 3: nBu4NOH (1 mL, 1m in MeOH) was added in small por-
tions to a solution of 2 (1.00 g, 0.89 mmol) in CH2Cl2 (30 mL) at room
temperature in the absence of light. The mixture was stirred for 3 h fol-
lowed by concentration under vacuum to 10 mL. The solution was added
dropwise to stirred n-hexane (600 mL) and cooled at À208C for 30 min.
The mixture was filtered through sintered glass with Celite, and the sol-
vent removed under vacuum to afford 3 as a yellowish powder (0.65 g,
85.0%). 1H NMR (400 MHz, C6D6, 258C, TMS): d=7.55–6.89 (m, 30H;
Ph), 4.40 ppm (s, 5H; Cp); 13C{1H} NMR (125 MHz, C6D6, 258C): d=
2
164.6 (t, J
G
100.3 (CCl3), 87.4 ppm (Cp); 31P{1H} NMR (162 MHz, C6D6, 258C): d=
50.40 ppm; MS (FAB+): m/z: 861.1; elemental analysis calcd (%) for
C43H35Cl3OP2Ru: C 62.76, H 4.10; found: C 62.71, H 4.12.
9: A solution of 2 (1.00 g, 0.89 mmol) in CH2Cl2 (30 mL) was passed
through an Al2O3 (acidic, activity grade I, height of column 1 cm) chro-
matography column. Elution with CH2Cl2 followed by removal of the sol-
vent under vacuum gave
9 as a yellowish powder (0.64 g, 73.1%).
4: Complex 3 (1.00 g, 1.16 mmol) was evenly spread on a 10 cmꢂ10 cm
glass plate and exposed to light from six 8 W mercury lamps (365 nm)
and was occasionally re-spread. After 24 h, the powder was dissolved in
CH2Cl2 (10 mL) and added dropwise to stirred n-hexane (200 mL) to
give a precipitate. The precipitate was collected by filtration and dried
under vacuum to give 4 as a yellow powder (0.75 g, 75.0%). 1H NMR
(400 MHz, C6D6, 258C, TMS): d=7.49–6.94 (m, 30H; Ph), 4.73 (s, 5H;
Cp); 13C{1H} NMR (125 MHz, C6D6, 258C): d=176.6 (CO), 127.8–137.8
(Ph, Ca and CCl), 109.1 (CCl2), 87.1 ppm (Cp); 31P{1H} NMR (162 MHz,
1H NMR (400 MHz, C6D6, 258C, TMS): d=7.53–6.89 (m, 30H; Ph), 4.47
(s, 5H; Cp), 3.60 ppm (br; OH); 13C{1H} NMR (125 MHz, C6D6, 258C):
d=138.5–128.7 (Ph), 125.8 (t, JACHTNUTRGNE(UNG P,C)=23.4 Hz; Ca), 105.8 (Cb) 104.3
(Cg), 87.0 (2C; CCl3), 85.8 ppm (Cp); 31P{1H} NMR (162 MHz, C6D6,
258C): d=51.9 ppm; MS (FAB+) m/z: 977.94; elemental analysis calcd
(%) for C46H36Cl6OP2Ru: C 56.35, H 3.70; found: C 56.33, H 3.72.
10: A mixture of 9 (1.00 g, 1.02 mmol) and a drop of HCl (0.1m in H2O)
in n-hexane (50 mL) was irradiated by light from six 8 W mercury lamps
(365 nm) for 2.5 h. n-Hexane was removed under vacuum and the residue
was purified through flash column chromatography on silica gel with
CH2Cl2. The product was dried under vacuum to afford 10 as a red
powder (0.43 g, 55.9%). 1H NMR (400 MHz, C6D6, 258C, TMS): d=
C6D6, 258C): d=48.05. MS (FAB+): m/z: 861.1; IR (Nujol): n˜CO
=
1751.3 cmÀ1 (s); elemental analysis calcd (%) for C43H35Cl3OP2Ru: C
62.76, H 4.10; found: C 62.55, H 4.08.
5:
A mixture of 4 (0.50 g, 0.58 mmol) and 2-methyl-1-buten-3-yne
7.60–6.92 (m, 15H; Ph), 5.48 (br, 1H; OH), 5.03 (s, 1H; =CH), 4.86 ppm
(0.55 mL, 5.80 mmol) in C6H6 (30 mL) was heated to 708C in a sealed
flask for 3 h. Solvent was removed under vacuum and the residue extract-
ed with n-hexane (3ꢂ30 mL). The extract was filtered through sintered
glass with Celite and the solvent of filtrate removed under vacuum to
afford 5 as an orange-red powder (0.29 g, 75.1%). 1H NMR (400 MHz,
(s, 5H; Cp); 13C{1H} NMR (125 MHz, C6D6, 258C): d=330.0 (d, J
A
2
14.5 Hz; Ca), 132.4–139.2 (Ph), 116.3 (Cb), 105.1 (Cg), 93.8 (Cp),
89.4 ppm (CCl3); 31P{1H} NMR (162 MHz, C6D6, 258C): d=48.82; MS:
(FAB+) m/z: 754.69; elemental analysis calcd for C28H22Cl7OPRu: C
44.56, H 2.94; found: C 44.76, H 3.08.
C6D6, 258C, TMS): d=7.32–6.93 (m, 15H; Ph), 6.50 (d, J
1H; H5), 4.25 (s, 5H; Cp), 3.00 (s, 1H; Hs), 1.75 (s, 3H; H4), 1.58 ppm (d,
(P,H)=14.6 Hz; Ha), numbering of atoms is shown in Scheme 4; 13C{1H}
NMR (125 MHz, C6D6, 258C): d=218.7 (m; C3), 175.8 (C8), 164.0 (d, J-
ACHTUNGTREN(NUNG P,H)=2.7 Hz,
11: nBu4NOH (1.0 mL, 1m, in MeOH) was added to a solution of 9
(0.50 g, 0.51 mmol) in CH2Cl2 (25 mL) at room temperature, and the mix-
ture stirred for 15 min. The solution was added dropwise to stirred n-
hexane (60 mL), cooled at À208C for 30 min, and filtered through sin-
tered glass with Celite, and the filtrate dried in vacuum to afford 11 as a
yellow powder (0.32 g, 81.0%). 1H NMR (400 MHz, C6D6, 258C, TMS):
d=7.63–6.90 (m, 30H; Ph), 4.38 (s, 5H; Cp), 3.57 ppm (s, 3H; OCH3);
13C{1H} NMR (125 MHz, C6D6, 258C): d=153.4 (CO), 134.5–128.8 (Ph
JACHTUNGTRENNUNG
ACHTUNGTRENNUNG JAHCTUNGTRE(NGNUN P,C)=
(P,C)=2.38 Hz; C6), 135.1–128.8 (Ph), 117.2 (C7), 108.1 (d,
6.79 Hz; C5), 89.1 (C9), 84.3 (Cp), 64.9 (C2), 37.8 (C1), 26.5 ppm (C4);
31P{1H} NMR (162 MHz, C6D6, 258C): d=58.99 ppm; MS (FAB+): m/z:
664.9; elemental analysis calcd (%) for C32H26Cl3OPRu: C 57.80, H, 3.94;
found: C 57.72, H, 3.99.
and Ca), 109.2(Cb), 86.2 (Cp), 50.8ACTHNUTRGNEUNG
(OMe); 31P{1H} NMR (162 MHz,
C6D6, 258C): d=50.47; MS (FAB+): m/z: 774.14; elemental analysis
calcd for C43H38O2P2Ru: C 69.85, H 4.95; found: C 69.77, H 4.88.
6: THF/H2O (5/50 mL) was added to 4 (0.63 g, 0.73 mmol) at room tem-
perature under N2, and the mixture heated to 508C and stirred for 18 h.
The solvent was removed at 508C by a rotary evaporator, the residue re-
dissolved in CH2Cl2 (5 mL), and the solution added to n-hexane
(100 mL) to precipitate a yellowish solid. The precipitate was collected,
Single-crystal X-ray diffraction analyses: Single crystals of 3, 4, 5, 6, and
10 suitable for X-ray diffraction study were grown as mentioned above.
Chem. Eur. J. 2009, 15, 3221 – 3229
ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.chemeurj.org
3227

Y.-C. Lin et al.
Single crystals were glued to glass fibers and mounted on a SMART
CCD diffractometer. The diffraction data were collected by using a 3 kW
sealed-tube MoKa radiation source (T=295 K). Exposure time was 5 s
per frame. SADABS[32] absorption correction was applied, and decay was
negligible. Data were processed and the structure was solved and refined
by SHELXTL.[33] Hydrogen atoms were placed geometrically by using a
riding model with thermal parameters set to 1.2 times that for the atoms
to which they are attached and 1.5 times for the methyl hydrogen atoms
(complex 5).
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Crystal data for 3: C45H35Cl3OP2Ru; Mr =861.09; 0.20ꢂ0.15ꢂ0.10 mm;
monoclinic space group P21/n; a=14.3270(2), b=18.2489(2), c=
15.1588(2) ꢁ;
b=97.569(1)8; Z=4;
V=3928.77(9) ꢁ3;
1calcd =
1.456 gcmÀ3
;
m=0.719 mmÀ1
; FACHTGRUNTENNUG(000)=1752; T=295(2) K; R1 =0.0501;
wR2 =0.1055; 6902 independent reflections.
Crystal data for 4: C45H35Cl3OP2Ru; Mr =861.09; 0.20ꢂ0.15ꢂ0.10 mm;
¯
triclinic space group P1; a=10.6805(1), b=12.7233(0), c=15.5564(2) ꢁ;
a=92.187(1), b=102.844(1), g=108.222(1)8; V=1944.45(3) ꢁ3; Z=2;
1calcd =1.471 gcmÀ3
; ; FACHTGUNTREN(UNNG 000)=876; T=295(2) K; R1 =
m=0.727 mmÀ1
0.0382; wR2 =0.0974; 8892 independent reflections.
Crystal data for 5: C32H26Cl3OPRu; Mr =664.92; 0.20ꢂ0.20ꢂ0.15 mm;
monoclinic space group C2/c; a=24.5269(3), b=14.8367(2), c=
19.6500(2) ꢁ;
b=124.720(1)8; Z=8;
V=5877.41(0) ꢁ3;
1calcd =
1.503 gcmÀ3
;
m=0.885 mmÀ1
; FACHTGRUNTENNUG(000)=2688; T=295(2) K; R1 =0.0357;
wR2 =0.0915; 6712 independent reflections.
Crystal data for 6·0.5CH2Cl2: C45.5H36Cl2O2P2Ru; Mr =848.65; 0.15ꢂ
0.15ꢂ0.10 mm; monoclinic space group P21/c; a=11.5015(1), b=
38.1370(5), c=18.2090(2) ꢁ; b=102.844(1)8; V=7714.1(1) ꢁ3; Z=8;
1calcd =1.461 gcmÀ3
; ; FACHTGUNTREN(UNNG 000)=3464; T=295(2) K; R1 =
m=0.666 mmÀ1
0.0513; wR2 =0.0982; 17674 independent reflections.
Crystal data for 10: C28H22Cl7OPRu; Mr =754.65; 0.20ꢂ0.15ꢂ0.05 mm;
monoclinic space group P21/c; a=12.7741(3), b=11.9146(2), c=
19.6617(4) ꢁ; b=91.426(2)8; V=2991.6(1) ꢁ3; Z=4; 1calcd =1.676 gcmÀ3
;
m=1.225 mmÀ1; F
6880 independent reflections.
ACHTUNGTRENNUNG(000)=1504; T=295(2) K; R1 =0.0285; wR2 =0.0619;
CCDC-676380 (4), CCDC-676381 (5), CCDC-699730 (10), CCDC-699731
(6), and CCDC-6997581 (3) contain the supplementary crystallographic
data for this paper. These data can be obtained free of charge from The
Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_
request/cif.
Computational methods: Theoretical calculations were carried out with
the Gaussian 03 program suite at the DFT level with the Becke 3 and
Lee–Yang–Parr (B3LYP) composite exchange-correlation functional.[34]
For radical compounds spin-unrestricted calculations were done; other-
wise, default options were used. The LanL2DZ basis set was used to de-
scribe the Ru and Cl atoms, and the 6-311++GACTHNUTRGNEUNG(d,p) basis set for the
rest of the atoms. For the full-molecule calculations on 3 and 4 the 6-
31G* and LanL2DZ basis sets were used. Full geometry optimization
without symmetry restrictions was performed for all structures. Harmonic
frequencies were calculated at the optimization level using the same
basis sets to examine whether local minima or first-order saddle points
were obtained. For each transition structure the intrinsic reaction coordi-
nate (IRC) method[35] was used with
a second-order integration
method[36] to verify whether the expected connections between thus-ob-
tained local maxima and local minima found on the potential energy sur-
face were correct. Solvent effects (chloroform, e=4.90), modeled as a
continuum medium, were considered by performing single-point calcula-
tions at the same level by using the self-consistent reaction field
(SCRF)[37] based on the polarizable continuum model (PCM) of Tomasi
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Acknowledgement
[16] Of 86 complexes with neutral CpACHTNUGTRNEUNG(PPh3)2RuR fragments whose struc-
This research is supported by the National Science Council and National
Center of High-Performance Computing of Taiwan, the Republic of
China.
tures were determined with R1 values of less than 7.1, 9 complexes
were dinuclear, and for the remaining 77 complexes, the average
3228
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ꢀ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
Chem. Eur. J. 2009, 15, 3221 – 3229

Ruthenium Vinylidene and Acetylide Complexes
FULL PAPER
À
Ru P distance of in the Cp
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Published online: February 6, 2009
Chem. Eur. J. 2009, 15, 3221 – 3229
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www.chemeurj.org
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