Exploitation of a chemically non-innocent acetate ligand in thesynthesis and reactivity of ruthenium vinylidene complexes

Article abstract of DOI:10.1021/om800950g

Reaction of the ruthenium bis-acetate complex cis-Ru(k²-OAc) ₂(PPh₃)₂ with a range of terminal alkynes HC=CR (R = Ph, C0₂Me, C{OH}Ph₂, C{OH}Me₂) results in the formation of the v

Full text of DOI:10.1021/om800950g

1320
Organometallics 2009, 28, 1320–1328
Exploitation of a Chemically Non-innocent Acetate Ligand in the
Synthesis and Reactivity of Ruthenium Vinylidene Complexes
Jason M. Lynam,* Christine E. Welby, and Adrian C. Whitwood
Department of Chemistry, UniVersity of York, Heslington, York, YO10 5DD, U.K.
ReceiVed October 2, 2008
Reaction of the ruthenium bis-acetate complex cis-Ru(κ2-OAc)2(PPh3)2 with a range of terminal alkynes
HCt CR (R ) Ph, CO2Me, C{OH}Ph2, C{OH}Me2) results in the formation of the vinylidene complexes
Ru(κ2-OAc)(κ1-OAc)(dCdCHR)(PPh3)2. The acetate ligands in these species are fluxional and, in the
case where R ) Ph, are undergoing fast exchange on the NMR time scale even at 195 K. In the case of
the hydroxy-substituted complex Ru(κ2-OAc)(κ1-OAc)(dCdCHC{OH}Ph2)(PPh3)2 a hydrogen bond exists
between the OH group on the γ-position of the vinylidene and the κ1-OAc ligand. This hydrogen bond
inhibits the exchange of the OAc ligands, which now becomes slow on the NMR time scale at 215 K.
In addition, and in contrast to the Cl-substituted analogues, elimination of water from the hydroxy
vinylidene complex does not readily occur, possibly due to the presence of this hydrogen-bonding
interaction. Instead, a slow reaction to form Ru(κ2-OAc)(κ1-OAc)(CO)(PPh3)2 is observed with the
concomitant formation of H2CdCPh2. An analogous process with Ru(κ2-OAc)(κ1-OAc)(dCdCHC-
{OH}Me2)(PPh3)2 affords H2CdCMe2 and Ru(κ2-OAc)(κ1-OAc)(CO)(PPh3)2.
C9H7; L′ ) phosphorus-based ligand).6 A similar strategy has
been employed for preparing complexes [RuCl(dCdCHR)-
Introduction
The ability of electron-rich metal complexes to facilitate the
conversion of terminal alkynes to their vinylidene tautomers
remains an area of considerable interest.1 The electrophilic
nature of the R-carbon dominates the reactivity of such
vinylidene ligands, a property that has been exploited in a wide
range of catalytic transformations involving terminal alkynes.2
The first step in the alkyne-vinylidene transformation is
typically coordination of the alkyne in an η2-fashion to a vacant
coordination site at the metal (Scheme 1). This is then followed
by a formal 1,2-hydrogen shift to afford the corresponding
vinylidene complex; this process is system dependent and may
proceed via either a concerted 1,2-hydrogen shift3 or a formal
oxidative addition of the C-H bond to give an intermediate
alkynyl-hydride complex,4,5 which undergoes a subsequent
hydride migration to give the vinylidene ligand. Regardless of
the precise mechanism of the 1,2-hydrogen shift, the requirement
that the metal possesses a vacant coordination site for alkyne
binding is a common feature in this transformation. Several
strategies have been employed to successfully achieve this goal.
For example, reaction of complexes RuCl(η5-L)(L′)2 with
terminal alkynes in the presence of a suitable halide scavenger
(typically sodium or ammonium salts) results in the formation
of vinylidene cations [Ru(dCdCHR)(η5-L)(L′)2]+ (L ) C5H5,
(P-P)2]+ (P-P ) chelating phosphine ligand) from cis-
RuCl2(P-P)2.7 In addition, the loss of neutral ligands has been
employed to generate the necessary vacant site at the metal.
For example, reaction of RuCl(η5-C5Me5)(PPh3)2 with HCt CPh
results in the displacement of a phosphine ligand and formation
of the neutral complex RuCl(η5-C5Me5)(dCdCPhH)(PPh3); the
phosphine loss pathway is enhanced by using benzene as solvent
and is presumably favored over halide loss on steric grounds
when compared to the corresponding Cp-derivative.8 A further
example of utilizing phosphine loss to prepare metal vinylidene
complexes has been reported by Wakatsuki.9 Here, reaction of
RuCl2(PPh3)3 with HCt CtBu results in the formation of RuCl2-
(dCdCHtBu)(PPh3)2.
An additional strategy that has been employed to create vacant
coordination sites at formally saturated metal centers to facilitate
(4) (a) Wolf, J.; Werner, H.; Serhadli, O.; Ziegler, M. L. Angew. Chem.,
Int. Ed. Engl. 1983, 22, 414. (b) Werner, H.; Alonso, F. J. G.; Otto, J.;
Wolf, J. Z. Naturforsch. B 1988, 43B, 722. (c) Werner, H.; Brekau, U. Z.
Naturforsch. B 1989, 44B, 1439. (d) Ho¨hn, A.; Werner, H. J. Organomet.
Chem. 1990, 382, 255. (e) Rappert, T.; Nu¨rnberg, O.; Mahr, N.; Wolf, J.;
Werner, H. Organometallics 1992, 11, 4156. (f) Werner, H.; Rappert, T.;
Baum, M.; Stark, A. J. Organomet. Chem. 1993, 459, 319. (g) Werner, H.;
Baum, M.; Schneider, D.; Windmu¨ller, B. Organometallics 1994, 13, 1089.
(h) Wakatsuki, Y.; Koga, N.; Werner, H.; Morokuma, K. J. Am. Chem.
Soc. 1997, 119, 360. (i) Suresh, C. H.; Koga, N. J. Theor. Comput. Chem.
2005, 4, 59. (j) Grotjahn, D. B.; Zeng, X.; Coosky, A. L. J. Am. Chem.
Soc. 2006, 128, 2798. (k) Grotjahn, D. B.; Zeng, X.; Cooksy, A. L.; Kassel,
W. S.; DiPasquale, A. G.; Zakharov, L. N.; Rheingold, A. L. Organome-
tallics 2007, 26, 3385. (l) De Angelis, F.; Sgamellotti, A.; Re, N.
Organometallics 2007, 26, 5285. (m) Cowley, M. J.; Lynam, J. M.; Slattery,
J. M. Dalton Trans. 2008, 4552.
(5) (a) de los R´ıos, I.; Jime´nez Tenorio, M.; Puerta, M. C.; Valerga, P.
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Tenorio, M.; Puerta, M. C.; Valerga, P. J. Am. Chem. Soc. 1997, 119, 6529.
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M. C.; Valerga, P. Organometallics 1999, 18, 950. (e) Aneetha, H.; Jime´nez-
Tenorio, M.; Puerta, M. C.; Valerga, P.; Mereiter, K. Organometallics 2003,
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M. C.; Valerga, P. J. Am. Chem. Soc. 2003, 125, 3311. (g) De Angelis, F.;
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* Corresponding author. E-mail: jml12@york.ac.uk.
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Organomet. Chem. 1994, 475, 45. (c) Puerta, M. C.; Valerga, P. Coord.
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2004, 689, 4092. (e) Antonova, A. B. Coord. Chem. ReV. 2007, 251, 1521.
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10.1021/om800950g CCC: $40.75
2009 American Chemical Society
Publication on Web 01/23/2009

ReactiVity of Ruthenium Vinylidene Complexes
Organometallics, Vol. 28, No. 5, 2009 1321
Scheme 1
Scheme 2. Formation of Allenylidene and Indenylidene
Complexesa
a
Key: (i) + HCt CC(OH)R2; (ii) - H2O; (iii) - PPh3, - H2O.
the alkyne/vinylidene conversion has involved the use of
hemilabile ligands.10-14 For example, Werner has demonstrated
that reaction of the phosphine-ether complex RuCl2(κ2-
iPr2PCH2CH2OMe)2 with HCt CPh results in the formation of
RuCl2 (dCdCHPh)(κ2 -i Pr2 PCH2 CH2 OMe)(κ1 {P}-
iPr2PCH2CH2OMe), the reaction presumably being enabled by
the change in coordination mode of the phosphine-ether ligand.10
Werner has also demonstrated that reaction of Ru(κ2-
affords the allenylidene complex. Although this synthetic route
has been applied to a wide range of metal substrates and is
generally robust, the reaction of HCt CCR2OH with
RuCl2(PPh3)3 does not give rise to an isolable complex
RuCl2(dCdCdCPh2)(PPh3)2; instead, the indenylidene complex
A (Scheme 2) is the ultimate product from the reaction.19
Importantly, this reaction remains one of the simplest routes to
prepare Grubbs-type metathesis catalysts, and the applications
of this compound, and its derivatives, have been reviewed.20
In this article we describe how the easily prepared complex
cis-Ru(κ2-OAc)2(PPh3)2, 1, may be utilized as a versatile
precursor to ruthenium vinylidene complexes. Importantly, the
presence of the two OAc ligands introduces a number of novel
structural features and reactivity when compared with, for
example, analogous complexes containing halide ligands.
i
OAc)2(PR3)2 (R ) Pr, Cy) (prepared from the reaction of
{Ru(κ1-O2CMe)(SbiPr3)2}2(µ-O2CMe)2(µ-OH2) with PR3) with
HCt CPh results in the formation of Ru(κ2-OAc)(κ1-
OAc)(PR3)2(dCdCHPh).15
The transformation of substituted terminal alkynes has also
been employed to prepare complexes containing longer cumu-
lene chains.16 Following the pioneering study of Selegue,17 the
most versatile route to generate allenylidene complexes
MdCdCdCR2 involves the reaction of propargylic alcohols
HCt CC{OH}R2 with suitable metal precursors (Scheme 2).18
Elimination of water, either spontaneously or promoted by acid
from an intermediate vinylidene complex MdCdCH-CR2OH,
Results and Discussion
a. Precursor Synthesis and Characterization. cis-Ru(κ2-
OAc)2(PPh3)2, 1, was prepared from the reaction of RuCl2(PPh3)3
with NaOAc using the procedure described by Wilkinson.21 To
the best of our knowledge, the precise molecular geometry of
1 has not been unambiguously determined; therefore, the
structure of 1 was established by a single-crystal X-ray
diffraction study (Figure 1). Selected bond lengths and angles
for 1 and for all structures reported are collected in Table 1,
and details of data collection and structural refinement in Table
2. The structure determination demonstrated that the ruthenium
is six-coordinate with two κ2-OAc ligands. The geometry
surrounding the metal is probably best viewed as a distorted
octahedron, with two of the PPh3 ligands in a mutually cis
arrangement (P(1)-Ru-P(2) 100.57(2)°). The remaining co-
ordination sites are occupied by the two OAc ligands. Each OAc
ligand has one oxygen atom in a position essentially trans to a
phosphine ligand (P(1)-Ru-O(3) 155.75(4)°; O(2)-Ru(1)-P(2)
154.58(4)°): O(1)-Ru-O(4) is also less than 180° (159.15(6)°).
The deviations from an idealized octahedral geometry may
simply be due to the small bite angle of the OAc ligands.
The difference in frequency (∆ν) between the symmetric and
asymmetric stretch of the acetate ligands is an effective probe
of the binding mode of the OAc ligand.22 The IR spectrum of
(6) (a) Bruce, M. I.; Wallis, R. C. Aust. J. Chem. 1979, 32, 1471. (b)
Bruce, M. I.; Wong, F. S.; Skelton, B. W.; White, A. H. J. Chem. Soc.,
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114, 5518. (f) Gamasa, M. P.; Gimeno, J.; Mart´ın-Vaca, B. M.; Borge, J.;
Garc´ıa-Granda, S.; Pe´rez-Carren˜o, E. Organometallics 1994, 13, 4045. (g)
Cadierno, V.; Gamasa, M. P.; Gimeno, J.; Borge, J.; Garc´ıa-Granda, S.
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L.; Dixneuf, P. H. Organometallics 1997, 16, 3640. (d) Touchard, D.;
Haquette, P.; Daridor, A.; Romero, A.; Dixneuf, P. H. Organometallics
1998, 17, 3844.
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A. H. J. Organomet. Chem. 1996, 522, 307. (b) Yang, S.-M.; Chan, M. C.-
W.; Cheung, K.-K.; Che, C.-M.; Peng, S.-M. Organometallic 1997, 16,
2819. (c) Bruce, M. I.; Hall, B. C.; Zaitseva, N. N.; Skelton, B. W.; White,
A. H. Dalton Trans. 1999, 1793.
(9) Wakatsuki, Y.; Koga, N.; Yamazaki, H.; Morokuma, K. J. Am. Chem.
Soc. 1994, 116, 8105.
(10) Werner, H.; Stark, A.; Schulz, M.; Wolf, J. Organometallics 1992,
11, 1126.
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Inorg. Chem. 1995, 34, 6106.
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Kirchner, K. J. Organomet. Chem. 2001, 617-618, 301.
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nometallics 1997, 16, 1714.
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C. L.; Beatty, A. M.; Valente, E. J.; Schanz, H. J. J. Organomet. Chem.
2007, 692, 5221.
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248, 1585.

1322 Organometallics, Vol. 28, No. 5, 2009
Lynam et al.
Cl2(PR3)2(dCdCHPh) (R ) iPr, Cy).24,25 The Ru-C(5)-C(6)
angle (176.5(2)°) is approximately linear, which is similar to
the related phenyl-substituted examples;23,24 however, the
t
corresponding angle in the Bu analogue shows a greater
deviation from linearity (161(2)°), which, as discussed by
Wakatsuki,9 is almost certainly the result of steric effects. The
incorporation of the acetate ligands has a profound effect on
the coordination geometry when compared to the halide-
substituted examples. Both RuBr2(PPh3)2(dCdCHtBu) and
RuCl2(PPh3)2(dCdC{SeiPr}Ph) adopt distorted trigonal-bipy-
ramidal geometries, as does OsCl2(PPh3)2(dCdCHBut),26 with
X-M-X angles (X ) Cl or Br, M ) Ru or Os) of 144.81(7)°,
144.89(6)°, and 149.31(2)°, respectively: the geometries of
RuCl2(PR3)2(dCdCHPh), which possess more bulky phosphine
ligands, are closer to square-based pyramidal (Cl-Ru-Cl
i
158.63(4)° R ) Pr and 156.93(2)° R ) Cy).
In contrast the largest angle between the OAc groups in 2a,
O(1)-Ru-O(3), is 168.17(7)°, which, combined with the fact
that the O(1)-Ru-C(5) and O(3)-Ru-C(5) angles are 97.81(9)°
and 93.90(9)°, respectively, indicates that the geometry of this
complex is probably best viewed as a distorted octahedron. The
most significant distortion from ideality arises from the κ2-OAc
group, with the angle between O(2) and remaining ligands being
constrained by the OAc framework. The remaining bond angles
around the ruthenium are close to their ideal values. When
compared to the five-coordinate halide analogues, the κ2-OAc
ligand may simply be viewed to be acting as an intramolecular
Lewis base in complex 2a, and the changes in geometry may
be rationalized on this basis. In a similar vein, for example, the
Cl-Os-Cl angle in OsCl2(PPh3)2(dCdCHPh)(OH2)26 is
158.56(5)°, again greater than the 16-electron analogue
OsCl2(PPh3)2(dCdCHtBu).
Figure 1. Structure of 1, with thermal ellipsoids, where shown, at
the 50% probability level. Hydrogen atoms and CH2Cl2 of crystal-
lization are omitted for clarity.
Table 1. Selected Bond Lengths (Å) and Angles (deg) for Complexes
1, 2a, 2c, and 3
1
2a
2c
3
Ru-P(1)
Ru-P(2)
Ru-O(1)
Ru-O(2)
Ru-O(3)
Ru-O(4)
Ru-C(5)
C(5)-C(6)
C(5)-O(5)
2.2467(5)
2.2463(5)
2.1000(14) 2.1139(17) 2.1100(11)
2.2353(15) 2.2863(18) 2.2588(11)
2.2362(15) 2.0699(17) 2.0344(11)
2.1072(14)
2.3853(7)
2.3910(7)
2.4178(4)
2.3652(4)
2.4060(4)
2.3873(4)
2.1466(11)
2.1897(11)
2.0365(11)
1.786(3)
1.318(4)
1.8027(15)
1.312(2)
1.8318(17)
1.146(2)
P(1)-Ru-P(2) 100.57(2)
P(1)-Ru-O(1) 93.55(4)
P(1)-Ru-O(2) 87.74(4)
P(1)-Ru-O(3) 155.75(4)
P(1)-Ru-O(4) 98.59(4)
O(1)-Ru-O(2) 60.48(5)
O(3)-Ru-O(4) 60.48(5)
O(1)-Ru-O(3) 103.56(6)
O(2)-Ru-O(3) 85.97(6)
O(1)-Ru-O(4) 159.15(6)
C(5)-Ru-P(1)
178.89(3)
89.08(5)
98.59(5)
93.06(5)
173.647(14) 176.545(15)
The NMR spectra of 2a confirm the presence of the
vinylidene ligand: for example a triplet resonance was observed
92.02(3)
82.82(3)
89.31(3)
95.14(3)
86.12(3)
87.52(3)
1
in the H NMR spectrum at δ 5.14 (4JPH ) 3.7 Hz) for the
proton attached to the vinylidene, and resonances for the R-
2
and ꢀ-carbons were observed at δ 355.6 (t, JPC ) 16.8 Hz)
59.08(6)
59.79(4)
60.42(4)
3
and δ 112.1 (t, JPC ) 4.4 Hz), respectively, in the 13C{1H}
168.17(7)
109.09(7)
156.68(4)
97.36(4)
155.62(5)
95.71(5)
spectrum. Only one series of resonances attributable to the OAc
1
groups was observed in the H and 13C{1H} NMR spectra of
2a at room temperature, suggesting that if the κ2 and κ1 bonding
modes were present in solution, then an exchange process, which
is rapid on the NMR time scale, must be occurring. On cooling,
the 1H NMR spectrum of 2a begins to exhibit broadening only
at 195 K, indicating that any fluxional process must have a low
energy barrier. In contrast, Werner has employed 19F NMR
spectra to demonstrate that degenerate exchange of trifluoro-
acetate ligands in Ru(κ2-O2CF3)(κ1-O2CF3)(PPri3)2(dCdCHPh)
is slow on the NMR time scale at 190 K, but rapid at 293 K.27
The IR spectra of 2a in solution show the presence of both
κ2 (1462 and 1531 cm-1; ∆ν ) 69 cm-1) and κ1 (1366 and
1594 cm-1; ∆ν ) 228 cm-1) forms of the acetate ligand.22
Presumably, the faster time scale of the IR experiment, when
compared to NMR, simply allows the two binding modes to be
distinguished. These results demonstrate that the binding modes
of the OAc ligands in 2a are fluxional and are converting
between κ2 and κ1 forms: this conversion is rapid on the NMR
time scale, but slow on the IR time scale.
87.77(8)
91.58(8)
97.81(9)
155.65(9)
93.90(9)
176.5(2)
96.95(5)
89.29(5)
101.35(6)
161.05(6)
101.59(6)
175.16(13)
91.24(5)
88.21(5)
104.71(6)
164.49(6)
99.45(6)
C(5)-Ru-P(2)
C(5)-Ru-O(1)
C(5)-Ru-O(2)
C(5)-Ru-O(3)
Ru-C(5)-C(6)
Ru-C(5)-O(5)
175.02(15)
1 recorded in CH2Cl2 solution confirms that the κ2-arrangement
is maintained in solution (1461 cm-1 (νOCOsym), 1513 cm-1
(νOCOasym), ∆ν(chelate) 52 cm-1).
b. Reaction of 1 with Terminal Alkynes HCt CR (R )
Ph, CO2Me). Treatment of a CH2Cl2 solution of 1 with
HCt CPh resulted in the formation of the vinylidene complex
Ru(κ2-OAc)(κ1-OAc)(PPh3)2(dCdCHPh), 2a, in good yield.
The structure of the complex was determined by a single-crystal
X-ray diffraction study. The structure determination (Figure 2)
demonstrated that the ruthenium is six-coordinate with both κ2
and κ1 acetate ligands. The structural metrics within the
vinylidene ligand are typical for this class of compound with
short Ru-C(5) (1.786(3) Å) and C(5)-C(6) (1.318(4) Å)
distances and are similar to those observed in RuBr2(PPh3)2-
(dCdCHtBu),9 RuCl2(PPh3)2(dCdC{SeiPr}Ph),23 and Ru-
Monitoring the formation of 2a by NMR spectroscopy at
room temperature demonstrated that the reaction between 1 and
(24) Katayama, H.; Ozawa, F. Organometallics 1998, 17, 5190.
(25) Wolf, J.; Stu¨er, W.; Gru¨nwald, C.; Gevert, O.; Laubender, M.;
Werner, H. Eur. J. Inorg. Chem. 1998, 1827.
(26) Wen, T. B.; Hung, W. Y.; Zhou, Z. Y.; Lo, M. F.; Williams, I. D.;
Jia, G. Eur. J. Inorg. Chem. 2004, 2837.
(23) Hill, A. F.; Hulkes, A. G.; White, A. J. P.; Williams, D. J.
Organometallics 2000, 19, 371.

ReactiVity of Ruthenium Vinylidene Complexes
Organometallics, Vol. 28, No. 5, 2009 1323
Table 2. Data Collection and Structural Refinement Details for Single-Crystal X-ray Diffraction Studies of 1 · CH2Cl2, 2a · 2CH2Cl2, 2c · CH2Cl2,
and 3
1 · CH2Cl2
2a · 2CH2Cl2
2c · CH2Cl2
3
empirical formula
fw
C41H38Cl2O4P2Ru
828.62
C50H46Cl4O4P2Ru
1015.68
C56H50Cl2O5P2Ru
1036.87
C41H36O5P2Ru
771.71
temp/K
wavelength/Å
110(2)
0.71073
110(2)
0.71073
110(2)
0.71073
110(2) K
0.71073
cryst syst
space group
monoclinic
P2(1)/c
triclinic
P1
monoclinic
P2(1)/n
triclinic
P1
j
j
a/Å
b/ Å
c/ Å
16.6515(13)
14.8443(11)
15.2203(11) Å
90
92.971(2)
90
3757.1(5)
4
1.465
11.4131(8)
14.0888(10)
15.2752(10)
73.9130(10)
89.8290(10)
84.941(2)
2350.2(3)
2
1.435
0.673
12.1131(5)
16.5914(7)
23.9945(10)
90
93.0550(10)
90
4815.4(3)
4
1.430
9.4889(9)
10.7254(10)
18.505(2)
100.934(2)°
104.233(2)
102.280(2)
1724.6(3)
R/deg
ꢀ/deg
γ/deg
volume/Å3
Z
2
density (calcd)/g/m3
absorp coeff/mm-1
F(000)
1.486
0.593
792
0.26 × 0.16 × 0.06
1.17 to 30.04
-13 e h e 13,
-15 e k e 14,
-26 e l e 26
19 579
0.686
1696
0.553
2136
1040
cryst size/mm3
φ range for data collection/deg
index ranges
0.16 × 0.12 × 0.05
1.22 to 28.30
-22 e h e 22,
-19 e k e 19,
-0 e l e 20
38 216
0.12 × 0.11 × 0.05
1.39 to 28.34
-15 e h e 15,
-18 e k e 18,
20 e l e 20
24 318
0.24 × 0.08 × 0.08
1.70 to 30.01
-16 e h e 17,
-23 e k e 23,
-33 e l e 33
54 123
reflns collected
independent reflns
completeness to θ
absorp corr
9325 [R(int) ) 0.0344]
99.8%
11 571 [R(int) ) 0.0328]
13 924 [R(int) ) 0.0276]
9681 [R(int) ) 0.0159]
95.9%
98.6%
99.1%
semiempirical from equivalents
max. and min. transmn
refinement method
data/restraints/params
goodness-of-fit on F2
final R indices [I > 2σ(I)]
0.970 and 0.711
0.970 and 0.865
0.957 and 0.858
0.965 and 0.842
full-matrix least-squares on F2
13 924/0/601
9325/0/453
1.069
11 571/8/582
1.018
9681/0/444
1.035
1.025
R1 ) 0.0354,
wR2 ) 0.0779
R1 ) 0.0427,
wR2 ) 0.0810
0.954 and -0.468
R1 ) 0.0442,
wR2 ) 0.0976
R1 ) 0.0612,
wR2 ) 0.1046
1.097 and -0.844
R1 ) 0.0313,
wR2 ) 0.0737
R1 ) 0.0416,
wR2 ) 0.0780
1.009 and -0.862
R1 ) 0.0269,
wR2 ) 0.0652
R1 ) 0.0350,
wR2 ) 0.0691
0.508 and -0.418
R indices (all data)
largest diff peak and hole/e Å-3
HCt CPh was extremely rapid. In general, the reaction between
1 and HCt CPh was complete within the time required to
acquire the NMR spectra, and no intermediates could be
observed. This is in stark contrast to the corresponding reaction
between RuCl2(PPh3)3 and HCt CtBu. In this case Wakatsuki
and co-workers demonstrated that loss of a PPh3 ligand is a
crucial step in the formation of RuCl2(PPh3)2(dCdCHtBu) and
that the reaction proceeds via intermediates B and C
(Scheme 3).9 In order to ensure that the difference exhibited in
the reaction of 1 and RuCl2(PPh3)3 was not simply due to the
different alkynes or conditions employed, the reaction of
RuCl2(PPh3)3 with HCt CPh was investigated under the condi-
tions used to prepare 2a. Analysis of the reaction mixture after
1 h by NMR spectroscopy demonstrated that, in addition to free
PPh3, OdPPh3, unreacted RuCl2(PPh3)3, and RuCl2(PPh3)2(dCd
CHPh), two further species, corresponding to intermediates B
and C, were observed as AB-type doublets. One exhibited
resonances at δ 47.5 and 47.1 (2JPP ) 38.5 Hz); the other at δ
34.7 and 33.1 (2JPP ) 25.3 Hz). These observations are
essentially identical to those reported by Watasuki, indicating
that the reaction of 1 with HCt CPh proceeds via a different
mechanism. It is proposed that the first step in the reaction of
1 with HCt CPh is that a OAc changes its binding mode from
κ2 to κ1, allowing the coordination of the alkyne. Transformation
of the alkyne to the vinylidene may occur to afford an
intermediate D, which may then isomerize to give the final
product 2a: this latter process may be aided by a reversible κ2
to κ1 shift from an OAc ligand.
In any event, it is clear that the formation of ruthenium
vinylidene complexes is far more rapid in the case of 1 than
RuCl2(PPh3)3. An interesting corollary to these results is the
observation that 1 has been shown to be a catalyst for the
coupling of terminal alkynes with azides to give triazoles,
whereas RuCl2(PPh3)3 is inactive.28 Given the reaction of 1 with
HCt CPh is so rapid, it is clear that 2a is a plausible intermediate
in this coupling reaction. The lack of reactivity exhibited by
RuCl2(PPh3)3 in this coupling reaction could then simply be due
to the more sluggish reaction with alkynes.
Figure 2. ORTEP diagram of 2a, with thermal ellipsoids, where
shown, at the 50% probability level. Hydrogen atoms, except for
H(6), and two molecules of CH2Cl2 of crystallization are omitted
for clarity.
(27) Gonzalez-Herrero, P.; Weberndorfer, B.; Ilg, K.; Wolf, J.; Werner,
H. Organometallics 2001, 20, 3672.

1324 Organometallics, Vol. 28, No. 5, 2009
Lynam et al.
Scheme 3a
a
Key: (i) + HCt CR, R ) Ph.
The reaction of 1 with HCt CCO2Me proceeded in a near
identical fashion to that with HCt CPh to afford Ru(κ2-OAc)(κ1-
OAc)(PPh3)2(dCdCHCO2Me), 2b, in good yield. The spec-
troscopic data for 2b support the proposed assignment, and the
NMR and IR data for the OAc ligands are essentially identical
to 2a, supporting the notion that the κ2/κ1 binding modes are
fluxional on the NMR time scale. Although single crystals of
2b could be grown, the quality of the resulting single X-ray
diffraction study was only sufficient to determine the gross
molecular topology, which was essentially identical to 2a, with
the CO2Me substituent again syn to the κ2-OAc ligand.
Attempts to incorporate internal alkynes RCt CR (R ) Me
or Ph) into the coordination sphere of ruthenium using this
method were unsuccessful. Treatment of 1 with these alkynes
did not result in any reaction.
c. Reaction of 1 with Propargylic Alcohols HCt C-
C(OH)R2 (R ) Ph, Me). As stated previously, the reaction of
suitable metal complexes with propargylic alcohols has been
shown to be a versatile route to allenylidene species MdCd
CdCR2.16-18 However, the reaction of RuCl2(PPh3)3 with
HCt CC(OH)Ph2 has been shown to be somewhat more
complex; in this instance the indenylidene A (Scheme 2) was
formed, presumably via an intermediate allenylidene species.
Clearly, given the importance of the indenyldiene species, and
the differences in behavior exhibited by 1 and RuCl2(PPh3)3 in
their interaction with terminal alkynes, it was clear that a study
of the interaction of the acetate-substituted complex with alkynes
HCt CC(OH)R2 (R ) Ph, Me) would be of interest.
Reaction of 1 with alkynes HCt CC(OH)R2 (R ) Ph, Me)
resulted in the formation of Ru(κ2-OAc)(κ1-OAc)(PPh3)2-
(dCdCHC{OH}R2) (2c R ) Ph; 2d R ) Me), in good yield.
The structure of 2c was established by a single-crystal X-ray
diffraction study (Figure 3). As in the previous studies of
complexes 2a and 2b, the presence of acetate ligands with both
κ2 and κ1 binding modes was observed. The metrics within the
vinylidene ligand are also similar to those observed previously,
although the Ru-C(5) bond is somewhat longer than the
corresponding distance in 2a. The most pertinent structural
feature exhibited by 2c is a hydrogen bond between the OH
group of the vinylidene ligand and the κ1-acetate ligand. The
O(5)-H(1) · · · O(4) distance is short (2.6905(17) Å), indicating
the presence of a strong hydrogen-bonding interaction. The two
phosphine ligands are not symmetrically coordinated to the
metal, with Ru-P bond lengths of 2.4178(4) and 2.3652(4) Å,
and this may be a consequence of the fact that the two phenyl
Figure 3. ORTEP diagram of 2c, with thermal ellipsoids, where
shown, at the 50% probability level. Hydrogen atoms, except for
H1 and H2, are omitted for clarity.
rings on the hydroxyvinylidene ligand, whose orientation is fixed
by the hydrogen bond, are asymmetrically substituted about a
plane containing the ruthenium, κ2-OAc, and vinylidene ligands
(distances from Ru-(κ2-OAc)-vinylidene plane: C(8) 1.613 Å;
C(14) 0.831 Å).
The existence of the hydrogen bond is also manifested in
1
the H NMR spectra of 2c. As in the case of 2a, only one
resonance for the methyl groups of the OAc groups is observed
at room temperature. In contrast to 2a, however, on cooling,
the resonance for the methyl groups broadens and then
undergoes coalescence at 235 K. Spectra recorded at 215 K
showed two distinct signals for the methyl groups of the OAc
groups (Figure 4). These data correspond to a free energy of
activation at 235 K of ∆Gq ) 9.7 kcal mol-1. These results
indicate that the rate of interconversion of the OAc ligands has
a higher barrier in the case of 2c, a fact that may be attributed
to the presence of the hydrogen bond between the OH group
and a κ1-acetate ligand.
Attempts to induce elimination of water from complex 2c
by, for example, treatment with acid or base or passage through
an acidic alumina column29 were unsuccessful, with starting
material being recovered in all cases. This is of course in direct
contrast to the corresponding interaction of RuCl2(PPh3)3 with
HCt CC(OH)Ph2. The difference in behavior may be due to
(28) Zhang, L.; Chen, X.; Xue, P.; Sun, H. H. Y.; Williams, I. D.;
Sharpless, K. B.; Fokin, V. V.; Jia, G. J. Am. Chem. Soc. 2005, 127, 15998.
(29) Martin, M.; Gevert, O.; Werner, H. J. Chem. Soc., Dalton Trans.
1996, 2275.

ReactiVity of Ruthenium Vinylidene Complexes
Organometallics, Vol. 28, No. 5, 2009 1325
1
Figure 4. Variable-temperature H NMR study of 2c at (a) 215 K, (b) 235 K, and (c) 255 K.
Wilkinson has previously reported the synthesis and charac-
terization of 3.30 The NMR data for the crystals obtained from
1
the solution of 2d and the resonances observed in the H and
31P{1H} during the decomposition of 2c and 2d matched those
of a sample of 3 independently prepared from 1. Although the
conversion of vinylidene ligands to carbonyls via hydrolysis31
or oxidation8b,32 is a well-established phenomenon, in this
instance a different reaction pathway appears to be occurring.
1
An examination of the H NMR spectra of the decomposition
reaction of 2c revealed the presence of a singlet resonance at δ
5.45, which, by comparison with an authentic sample, was
shown to be due to the alkene protons of H2CdCPh2: an
integration of this resonance demonstrated that it was formed
in identical quantities to 3 and was the major organic product
(>95%) from the reaction. The corresponding spectra for the
decomposition of 2d again exhibited resonances for a single
major organic product that exhibited a septet resonance of
relative integration 2 at δ 4.64 (4JHH ) 1.0 Hz) and a triplet
resonance of integration 6 at δ 1.71 (4JHH ) 1.0 Hz), presumably
indicating the formation of H2CdCMe2.
Figure 5. ORTEP diagram of 3, with thermal ellipsoids, where
shown, at the 50% probability level. Hydrogen atoms are omitted
for clarity.
The transformation of propargylic alcohols HCt CC(OH)R2
into CO and alkenes H2CdCR2 has been shown to be catalyzed
by [RuTp(NCMe)2(PPh3)][PF6] (Tp ) tris{1-pyrazolyl}borate)
with LiOTf as cocatalyst.33 In this instance, the reaction was
thought to proceed via an intermediate formed by nucleophilic
attack by LiOH at the R-carbon of an allenylidene ligand. In
the hydrogen-bonding interaction described above stabilizing
the hydroxyl-substituted vinylidene complex, thus inhibiting
elimination of water.
On storage for several weeks, CD2Cl2 solutions of 2c and 2d
underwent a further reaction. Over this period of time, the
resonance in the 31P{1H} NMR spectrum due to the vinylidene
complexes was observed to decrease in intensity, to be replaced
by a singlet resonance at δ 39.1 in both cases. The species
responsible for this resonance was identified as Ru(κ2-OAc)(κ1-
OAc)(PPh3)2(CO), 3. Crystals of 3 suitable for study by single-
crystal X-ray diffraction were obtained from slow diffusion of
hexane into a CD2Cl2 solution of 2d that had been permitted to
stand for 17 weeks. The subsequent structure determination
(Figure 5) revealed that the ruthenium motif was similar to those
observed for 2a, 2b, and 2c, although the Ru-O(2) bond length
is somewhat shorter than in the vinylidene analogues, presum-
ably indicating that the carbonyl ligand is a better π-acceptor
than vinylidene. This phenomenon may also be manifested in
the observation that the C(5)-Ru-O(2) angle in 3 is greater
than in 2a, 2b, or 2c.
(30) Spencer, A.; Wilkinson, G. J. Chem. Soc., Dalton Trans. 1974,
786.
(31) (a) Abu Salah, O. M.; Bruce, M. I. J. Chem. Soc., Dalton Trans.
1974, 2302. (b) Bruce, M. I.; Swincer, A. G. Aust. J. Chem. 1980, 33, 1471.
(c) Sullivan, B. P.; Smythe, R. S.; Kober, E. M.; Meyer, T. J. J. Am. Chem.
Soc. 1982, 104, 4701. (d) Mountassir, C.; Ben Hadda, T.; Le Bozec, H. J.
Organomet. Chem. 1990, 388, C13. (e) Knaup, W.; Werner, H. J.
Organomet. Chem. 1991, 411, 471. (f) Bianchini, C.; Casares, J. A.;
Peruzzini, M.; Romerosa, A.; Zanobini, F. J. Am. Chem. Soc. 1996, 118,
4585.
(32) (a) Bruce, M. I.; Swincer, A. G.; Wallis, R. C. J. Organomet. Chem.
1979, 171, C5. (b) Oro, L. A.; Ciriano, M. A.; Campo, M.; Foces-Foces,
C.; Cano, F. H. J. Organomet. Chem. 1985, 289, 117. (c) Mezzetti, A.;
Consiglio, G.; Morandini, F. J. Organomet. Chem. 1992, 430, C15. (d) Le
Lagadec, R.; Roman, E.; Toupet, L.; Mu¨ller, U.; Dixneuf, P. H. Organo-
metallics 1994, 13, 5030. (e) Bianchini, C.; Innocenti, P.; Preuzzini, M.;
Romerosa, A.; Zanobini, F. Organometallics 1996, 15, 272. (f) de los R´ıos,
I.; Jime´nez-Tenorio, M.; Puerta, M. C.; Valerga, P. J. Organomet. Chem.
1997, 549, 221.

1326 Organometallics, Vol. 28, No. 5, 2009
Lynam et al.
Scheme 4. (a) Proposed Mechanism for the Conversion of Complexes 2c and 2d to 3 and Alkenes and (b) Thermal Dissociation
of Oxetan-2-one to CO2 and Ethanea
2
a
Key: [Ru] ) Ru(κ -OAc)(PPh3)2; 2c, R ) Ph; 2d R ) Me.
addition, Dixneuf has demonstrated that the reaction of com-
plexessuchasRuCl(OTf)(p-cymene)(PR3)withHCt CC(OH)PhH
results in the formation of [RuCl(p-cymene)(CO)(PR3)][OTf]
and styrene: in this instance a hydroxycarbene intermediate, E,
was observed, which was believed to be formed by the reaction
of water with an allenylidene complex.34
vinylidene ligands MdCdC(Ph)CH2R to afford cyclopropenyl
complexes is also well documented.36
Opening of the four-membered ring in F may then afford a
hydroxycarbene complex G related to that observed by Dixneuf
or, alternatively, hydrogen migration, possibly assisted by the
OAc ligand through H, would then afford the oxetane complex
I. Elimination of the alkene from this species would then afford
3 and the alkenes. This latter process may be viewed as a metal-
containing analogue of the expulsion of CO2 from oxetan-2-
one (Scheme 4b)37 or, indeed, the elimination of alkenes and
OdPPh3 from oxaphosphetanes in the Wittig reaction.38
Interestingly, the mechanism we propose involving a four-
membered intermediate such as F is consistent with the
deuterium and 18O labeling studies reported by Liu and
co-workers in their catalytic study.33
Although we cannot discount the presence of such processes
occurring in the case of complexes 2c and 2d, given the apparent
reluctance of these species to dehydrate to form allenylidene
ligands, we propose that an alternative mechanism may be
occurring. It is proposed that the alkenes are formed via
intramolecular attack of the OH group to the R-position of the
vinylidene ligand in complexes 2c and 2d to give a complex
containing a four-membered ring F (Scheme 4a). An examina-
tion of the crystal structure of 2c reveals that, as a consequence
of the hydrogen bonding between the κ1-OAc group and the
OH, the oxygen atom is in close proximity to the R-carbon of
the vinylidene ligand (O(5)-C(1) 2.770 Å). There are manifold
examples of related intramolecular cyclization reactions of 4-
and 5-hydroxy-substituted vinylidene complexes to give metal
carbene complexes,35 and formation of three-membered rings
from the base-promoted cyclization of species containing
Conclusions
We have demonstrated that 1 may act as a versatile precursor
to a range of substituted vinylidene complexes. Importantly, the
ability of the acetate ligand to act in a hemilabile fashion not
only allows for the facile incorporation of the alkyne into the
coordination sphere of the metal but, additionally, ensures that
the resulting complex maintains a formal 18-electron configu-
ration. The difference in behavior between the halide and acetate
complexes is exemplified in the case of the propargylic-
substituted systems in which drastic differences in reactivity
toward the elimination of water are observed. In the case of
(33) Datta, S.; Chang, C.-L.; Yeh, K.-L.; Liu, R.-S. J. Am. Chem. Soc.
2003, 125, 9294.
(34) (a) Bustelo, E.; Dixneuf, P. H. AdV. Synth. Catal. 2005, 347, 393.
(b) Bustelo, E.; Dixneuf, P. H. AdV. Synth. Catal. 2007, 349, 933.

ReactiVity of Ruthenium Vinylidene Complexes
Organometallics, Vol. 28, No. 5, 2009 1327
in degassed tBuOH. The mixture was heated at reflux for 1 h, after
which time a color change from black to orange-red was observed.
When cool, the solid was filtered and washed with 80 mL of H2O,
60 mL of CH3OH, and finally 50 mL of Et2O. The orange powder
was dried in Vacuo. Crystals suitable for X-ray diffraction were
obtained from a CD2Cl2 solution. Yield: 3.57 g, 92%.
OAc-containing complexes this reluctance to eliminate water
enables the observation of a more unusual reaction for hydrox-
yvinylidene ligands, which involved the expulsion of an alkene
from the coordination sphere of the metal with concomitant
formation of a metal carbonyl.
We intend to explore the reactivity of the hydroxyvinylidene
ligands, which should be aided by the fact that the elimination
of the alkene from these species is relatively slow. In addition,
we will address the potential of these complexes as catalysts
for a range of transformations of terminal alkynes. In this context
it is interesting to note that attempts to replace the PPh3 ligands
in 2a with PCy3 in order to assess the potential of these
complexes as catalysts in metathesis reactions proved to be
remarkably troublesome, as mixtures were obtained in all
reaction conditions employed. This observation is somewhat
surprising given the often facile exchange reactions of this type
reported for Grubbs-type catalysts and the indenylidene complex
A.20b Although we have not, to date, been able to elucidate the
reasons for this lack of selectivity, it may again be a manifesta-
tion of the different properties of OAc and halide ligands.
NMR spectra CD2Cl2: 1H (300.13 MHz) δH 1.48 (s, 6H,
COOCH3), 7.13-7.32 (m, 30H, PPh3); 31P (121.40 MHz) δP 63.1
(s, PPh3); 13C (76.98 MHz) δC 25.4 (s, COOCH3), 129.8 (t, 4.69
Hz, PPh3-C3), 131.5 (s, PPh3-C4), 136.4 (t, 5.03 Hz, PPh3-C2), 137.3
3
(1JPC+ JPC ) 44.4 Hz, PPh3-C1), 190.6 (s, COOCH3); IR (KBr),
1433 cm-1 (P-Ph), 1456 cm-1 (κ2-OCOsym), 1516 cm-1 (κ2-
OCOasym), ∆ν(chelate) 61 cm-1; (CH2Cl2) 1434 cm-1 (P-Ph), 1461
cm-1 (κ2-OCOsym), 1513 cm-1 (κ2-OCOasym), ∆ν(chelate) 52 cm-1; MS
(FAB), 744 m/z (M+),685 m/z ([Ru(OAc)(PPh3)2]+), 625 m/z
([Ru(PPh3)2]+), 482 m/z ([Ru(OAc)2(PPh3)]+), 423 m/z ([Ru(OAc)(P-
Ph3)]+), 363 m/z ([Ru(PPh3)]+).
Synthesis of Ru(K2-OAc)(K1-OAc)(PPh3)2(dCdCHPh), 2a.
HCt CPh (31.0 µL, 0.28 mmol) was added to a solution of cis-
Ru(κ2-OAc)2(PPh3)2 (0.21 g, 0.28 mmol) in 15 mL of CH2Cl2 and
was stirred for 1 h. The volume was reduced slightly in Vacuo before
addition of 20 mL of hexane or pentane, resulting in the formation
of a pink precipitate. The solid was isolated by filtration, washed
with 2 × 20 mL portions of hexane or pentane, and dried under
vacuum. If required, the product could be further purified by
recrystallization from a CH2Cl2/hexane or CH2Cl2/pentane solution.
Crystals for X-ray diffraction were obtained from a CD2Cl2 solution
of 2a. Yield: 0.32 g (71%).
Experimental Section
All experimental procedures were performed under an atmo-
sphere of dinitrogen or argon using standard Schlenk line and
glovebox techniques. CH2Cl2, pentane, and hexane were purified
with the aid of an Innovative Technologies anhydrous solvent
engineering system. tBuOH and MeOH were degassed by purging
with dinitrogen prior to use. The Et2O was AR grade and used
without any further purification. The CD2Cl2 used for NMR
experiments was dried over CaH2 and degassed with three
freeze-pump-thaw cycles. The solvent was then vacuum trans-
ferred into NMR tubes fitted with PTFE Young’s taps. NMR spectra
were acquired on either a Bruker AMX 300 (operating frequencies
1H 300.13 MHz, 31P 121.40 MHz, 13C 76.98 MHz) or a Bruker
AVANCE 500 (operating frequencies 1H 500.23 MHz, 31P 202.50
MHz, 13C 125.77 MHz). 31P and 13C spectra were recorded with
proton decoupling. Mass spectrometry measurements were per-
formed on a Thermo-Electron Corp LCQ Classic (ESI) or a Fisons
Analytical (VG) Autospec instrument (FAB). IR spectra were
acquired on either a Mattson Research Series or Thermo-Nicolet
Avatar 370 FTIR spectrometer either using CsCl solution cells or
as KBr discs. RuCl2(PPh3)3 was prepared by the literature method.39
HCt CPh was obtained from Acros Organics and purified by
passage through an alumina column and degassed by three
freeze-pump-thaw cycles. HCt CC(OH)R2 (R ) Ph, Me) and
HCt CCO2CH3 were obtained from Aldrich Chemicals and were
used as supplied. cis-Ru(κ2-OAc)2(PPh3)2, 1,21 and Ru(κ2-OAc)(κ1-
OAc)(PPh3)2(CO), 3,30 were prepared by minor modifications of
the literature procedures as detailed below.
1
NMR spectra CD2Cl2: H δH 0.81 (s, 6H, COOCH3), 5.14 (t,
4JPH ) 3.7 Hz, 1H, RudCdCHPh), 6.77 (d, 7.7 Hz, 2H, ortho-H
of CHPh), 6.83 (at, 7.4 Hz, 1H, H4-CHPh), 7.04 (t, 7.7 Hz, 2H,
H3-CHPh), 7.27, (t, 7.4 Hz, 12H, H3-PPh3), 7.35 (t, 7.4 Hz, 6H,
H4-PPh3), 7.46 (m, 12H, H2-PPh3); 31P δP 34.1 (s, PPh3); 13C 21.9,
(s, COOCH3), 112.1 (t, 3JPC ) 4.4 Hz, RudC)C), 123.7 (s, CHPh-
C4), 124.7, (s, CHPh-C2/C3), 127.9 (vt, 3JPC+5JPC ) 9.1 Hz, PPh3-
C3), 129.6 (vt, 1JPC+3JPC ) 43.6 Hz, PPh3-C1), 130.0 (s, PPh3, C4),
4
2
133.4 (t, JPC ) 2.92 Hz, CHPh, C1), 134.9 (t, JPC+4JPC ) 12.4
Hz, PPh3-C2), 179.6 (s, COOCH3), 355.6 (t, 2JPC ) 16.8 Hz, RudC);
IR (KBr) 1360 cm-1 (κ1-OCOsym), 1435 cm-1 (P-Ph), 1459 cm-1
(κ2-OCOsym), 1534 cm-1 (κ2-OCOasym), 1595 cm-1 (κ1-OCOasym),
1635 cm-1 (CdC), ∆ν(uni) 235 cm-1, ∆ν(chelate) 75 cm-1; (CH2Cl2)
1366 cm-1 (κ1-OCOsym), 1435 cm-1 (P-Ph), 1462 cm-1 (κ2-OCOsym),
1531 cm-1 (κ2-OCOasym), 1594 cm-1 (κ1-OCOasym), 1630 cm-1
(CdC), ∆ν(uni) 228 cm-1, ∆ν(chelate) 69 cm-1; MS (FAB), 846 m/z
(M+), 787 m/z ([Ru(OAc)(dCdCHPh)(PPh3)2]+), 727 m/z
([Ru(dCdCHPh)(PPh3)2]+), 685 m/z ([Ru(OAc)(PPh3)2]+), 625
m/z ([Ru(PPh3)2]+), 584 m/z ([Ru(OAc)2(dCdCHPh)(PPh3)]+), 524
m/z ([Ru(OAc)(dCdCHPh)(PPh3)]+). Anal. for RuP2O4C48H42,
(calc) C 68.15, H 5.02; (found) C 67.79, H 4.99.
Synthesis of Ru(K2-OAc)(K1-OAc)(PPh3)2(dCdCHCO2CH3),
2b. The pale yellow complex Ru(κ2-OAc)(κ1-OAc)(PPh3)2-
(dCdCHCO2CH3) was prepared in a similar manner to that
described for Ru(κ2-OAc)(κ1-OAc)(PPh3)2(dCdCHPh) using cis-
Ru(κ2-OAc)2(PPh3)2 (0.20 g, 0.27 mmol), HCt CCO2CH3 (24.0 µL,
0.27 mmol), and 20 mL of CH2Cl2. Crystals for X-ray diffraction
were obtained from a CH2Cl2/hexane solution. Yield: 0.13 g (59%).
Synthesis of cis-Ru(K2-OAc)2(PPh3)2, 1. NaOAc (4.31 g, 52.5
mmol) was added to a solution of RuCl2(PPh3)3 (5.03 g, 5.25 mmol)
(35) (a) Bianchini, C.; Marchi, A.; Mantovani, N.; Marvelli, L.; Masi,
D.; Peruzzini, M.; Rossi, R. Eur. J. Inorg. Chem. 1998, 211. (b) Gamasa,
M. P.; Gimeno, J.; Mart´ın-Vaca, B. M.; Isea, R.; Vegas, A. J. Organomet.
Chem. 2002, 651, 22. (c) Keller, A.; Jasionka, B.; Glowiak, T.; Ershov, A.;
Matusiak, R. Inorg. Chim. Acta 2003, 344, 49. (d) Grime, R. W.; Helliwell,
M.; Hussain, Z. I.; Lancashire, H. N.; Mason, C. R.; McDouall, J. J. W.;
Mydlowski, C. M.; Whiteley, M. W. Organometallics 2008, 27, 857.
(36) (a) Ting, P. C.; Lin, Y. C.; Lee, G. H.; Cheng, M. C.; Wang, Y.
J. Am. Chem. Soc. 1996, 118, 6433. (b) Lo, Y. H.; Lin, Y. C.; Lee, G. H.;
Wang, Y. Organometallics 1999, 18, 982. (c) Chang, C. W.; Lin, Y. C.;
Lee, G. H.; Wang, W. Organometallics 2000, 19, 3211. (d) Lin, Y. C. J.
Organomet. Chem. 2001, 617-618, 141.
(37) Frey, H. M.; Pidgeon, I. M. J. Chem. Soc., Faraday Trans. 1 1985,
81, 1087.
(38) Maryanoff, B. E.; Reitz, A. B. Chem. ReV. 1989, 89, 863.
(39) Hallman, P. S.; Stephenson, T. A.; Wilkinson, G. Inorg. Synth. 1970,
12, 237.
1
NMR spectra CD2Cl2: H δH 0.78 (s, 6H, COOCH3) 3.46 (s, 3H,
4
RudCdCHCO2CH3), 4.51, (t, JPH ) 3.2 Hz, 1.H, RudCdCH),
7.33-7.47, (m, 38.5H, PPh3); 31P δP 34.8 (s, PPh3);13C δC 21.8 (s,
3
CO2CH3), 50.5 (s, RudCdCH-C), 104.4 (t, JPC ) 3.9 Hz,
3
RudCdC), 128.0 (t, JPC+5JPC ) 9.6 Hz, PPh3-C3), 128.9, (t,
1JPC+3JPC ) 44.4 Hz, PPh3-C1), 130.3 (s, PPh3-C4), 134.9 (t,
2JPC+4JPC ) 12.2 Hz, PPh3-C2), 167.7 (s, RudCdCHCO2CH3),
179.8 (s, COOCH3), 345.2 (m, RudC); IR (KBr) 1365 cm-1 (κ1-
OCOsym), 1433 cm-1 (P-Ph), 1460 cm-1 (κ2-OCOsym), 1533 cm-1
(κ2-OCOasym), 1600 cm-1 (κ1-OCOasym), 1696 cm-1 (CdC), ∆ν(uni)
235 cm-1, ∆ν(chelate) 73 cm-1; IR (CH2Cl2) 1365 cm-1 (κ1-OCOsym),

1328 Organometallics, Vol. 28, No. 5, 2009
Lynam et al.
1435 cm-1 (P-Ph), 1466 cm-1 (κ2-OCOsym), 1535 cm-1 (κ2-
OCOasym), 1600 cm-1 (κ1-OCOasym), 1684 cm-1 (CdC), ∆ν(uni) 235
cm-1, ∆ν(chelate) 69 cm-1; MS (ESI), m/z 851.1269 [M]Na, 754.1209.
Anal. for RuP2O5C45H44 + (0.75 CH2Cl2) (calc), C 60.62, H 4.63;
(found) C 60.74, H 4.70.
207.4 (t, 2JPC ) 13.2 Hz, RuCO); IR (KBr) 1368 cm-1 (κ1-OCOsym),
1435 cm-1 (P-Ph), 1466 cm-1 (κ2-OCOsym), 1520 cm-1 (κ2-
OCOasym), 1607 cm-1 (κ1-OCOasym), 1941 cm-1 (CO), ∆ν(uni) 239
cm-1, ∆ν(chelate) 54 cm-1; (CH2Cl2) 1373 cm-1 (κ1-OCOsym), 1437
cm-1 (P-Ph), 1468 cm-1 (κ2-OCOsym), 1520 cm-1 (κ2-OCOasym),
1603 cm-1 (κ1-OCOasym), 1946 cm-1 (CO), ∆ν(uni) 230 cm-1
,
Synthesis of Ru(K2-OAc)(K1-OAc)(PPh3)2(dCdCHC{OH}Ph2),
2c. The bright yellow complex Ru(κ2-OAc)(κ1-OAc)(PPh3)2-
(dCdCHC{OH}Ph2) was prepared in a similar manner to that
described for Ru(κ2-OAc)(κ1-OAc)(PPh3)2(dCdCHPh) using 0.50 g
of cis-Ru(κ2-OAc)2(PPh3)2 (0.67 mmol), 0.14 g of HCt CCPh2OH
(0.67 mmol, 1.0 equiv), and 30 mL of CH2Cl2. Crystals for X-ray
diffraction were obtained from a CH2Cl2/hexane solution. Yield:
0.55 g (86%). NMR spectra CD2Cl2: 1H δH 0.71 (s, 6H, COOCH3),
∆ν(chelate) 52 cm-1
.
Decomposition Studies of 2c and 2d. In a typical experiment 1
(30 mg, 0.04 mmol) was dissolved in 0.5 cm3 of CD2Cl2, and 1
equiv of the appropriate alkyne HCt CC(OH)R2, (2c R ) Ph; 2d
R ) Me) added. The decomposition to form 3 and H2CdCR2
samples was monitored by 1H and 31P NMR over an extended period
of time (in the case of 2c for 4 weeks and 2d for 17 weeks).
Reaction of RuCl2(PPh3)3 with HCt CPh. RuCl2(PPh3)3 (0.30
g, 0.31 mmol) was dissolved in 30 mL of CH2Cl2. To this was
added 35.0 µL of HCt CPh (35.0 µL, 0.31 mmol), and the mixture
was stirred for 1 h. The solvent was then removed in Vacuo to
afford a dark brown residue. This was washed with 3 × 20 mL
portions of pentane and then dried under vacuum. NMR spectra
CD2Cl2: 31P (202.49 MHz) δP -5.48 (s, free PPh3), 27.2 (s,
4
4.73 (t, JPH ) 3.9 Hz, 1H, RudCdCHC{OH}Ph2), 4.88 (s, 1H,
RudCdCHC{OH}Ph2), 6.93-7.03 (m, 10H, RudCdCHC-
{OH}Ph2), 7.24-7.37 m, (30H, PPh3); 31P δP 34.0 (s, PPh3); 13C
δC 21.7 (s, COOCH3), 74.0 (s, RudCdCH-CPh2OH), 117.2 (t,
3JPC ) 4.7 Hz, RudCdC), 125.9, (CPh2-C4), 126.2 (s, CPh2-C2/
3
5
C3), 127.7 (s, CPh2-C2/C3), 128.0 (t, JPC + JPC ) 9.8 Hz, PPh3-
1
3
C3), 129.4 (t, JPC + JPC 42.2 Hz, PPh3-C1), 130.1 (s, PPh3-C4),
2
2
135.0 (t, 2JPC + 4JPC ) 11.6 Hz, PPh3-C2), 149.8 (s, CPh2-C1), 179.6
OdPPh3), δ 33.1 (d, JPP ) 25.3 Hz), δ 34.7 (d, JPP ) 25.3 Hz),
2
2
2
δ 47.5 (d, JPP ) 38.5 Hz), 47.1 (d, JPP ) 38.5 Hz).
(s, CO2CH3), 347.6 (t, JPC ) 16.2 Hz, RudC); IR (KBr) 1378
cm-1 (κ1-OCOsym), 1434 cm-1 (P-Ph), 1465 cm-1 (κ2-OCOsym), 1527
cm-1 (κ2-OCOasym), 1595 cm-1 (κ1-OCOasym), 1654 cm-1 (CdC),
∼3260 cm-1 (OH), ∆ν(uni) 217 cm-1, ∆ν(chelate) 62 cm-1; (CH2Cl2)
1371 cm-1 (κ1-OCOsym), 1435 cm-1 (P-Ph), 1463 cm-1 (κ2-OCOsym),
1531 cm-1 (κ2-OCOasym), 1598 cm-1 (κ1-OCOasym), 1649 cm-1
Reaction of 1 with PhCt CPh. PhCt CPh (5.13 mg, 0.03 mmol)
was added to a solution of 1 (21.4 mg, 0.03 mmol) in 0.5 mL of
CD2Cl2. This solution was monitored by 1H and 31P NMR
spectroscopy over 11 days. The 31P NMR spectra recorded over
this time indicated that no reaction had occurred.
(CdC), 3276.1 cm-1 (OH), ∆ν(uni) 227.0 cm-1, ∆ν(chelate) 68 cm-1
;
Reaction of 1 with MeCt CMe. MeCt CMe (2.49 µL, 0.03
mmol) was added to a solution of 1 (23.6 mg, 0.03 mmol) in 0.5
MS (ESI), m/z 975.1914 [M]Na, 713.1321 [Ru(OAc)2(PPh3)-
(dCdCHCPh2OH)]Na+. Anal. for RuP2O4Cl2C56H50 (calc), C
64.86, H 4.86; (found) C 64.33, H 4.77.
1
mL of CD2Cl2. This solution was monitored by H and 31P NMR
spectroscopy over 3 days The 31P NMR spectra recorded over this
time indicated that no reaction had occurred.
Synthesis of Ru(K2-OAc)(K1-OAc)(PPh3)2(dCdCHC{OH}Me2),
2d. The pale orange-yellow complex Ru(κ2-OAc)(κ1-OAc)(PPh3)2-
(dCdCHC{OH}Me2) was prepared in a similar manner to that
described for Ru(κ2-OAc)(κ1-OAc)(PPh3)2(dCdCHPh) using cis-
Ru(κ2-OAc)2(PPh3)2 (0.38 g, 0.51 mmol), HCt CC(OH)Me2 (50.0
µL, 0.51 mmol), and 30 mL of CH2Cl2. Yield: 0.32 g (76%). NMR
Details of X-ray Diffraction Analysis. Details of the collection
and refinement are presented in Table 2. Diffraction data were
collected at 110 K on a Bruker Smart Apex diffractometer with
Mo KR radiation (λ ) 0.71073 Å) using a SMART CCD camera.
Diffractometer control, data collection, and initial unit cell deter-
mination was performed using SMART.40 Frame integration and
unit-cell refinement software was carried out with SAINT+.41
Absorption corrections were applied by SADABS (v2.03, Sheld-
rick). Structures were solved by direct methods using SHELXS-
9742 and refined by full-matrix least-squares using SHELXL-97.43
All non-hydrogen atoms were refined anisotropically. Hydrogen
atoms were placed using a “riding model” and included in the
refinement at calculated positions.
1
spectra CD2Cl2: H δH 0.68 (s, 6.H, RudCdCHC{OH}Me2, 0.77
4
(s, 6H, COOCH3), 4.32, (t, JPH
)
3.9 Hz, 1H,
RudCdCHC{OH}Me2), 7.33-7.45, (m, 30H, PPh3); 31P δP 34.1
(s, PPh3); 13C δC 22.0 (s, COOCH3), 30.9 (s, RudCdCHCMe2),
3
67.9 (s, RudCdCH-C), 118.4 (t, JPC ) 4.78 Hz, RudCdC),
3
5
1
3
128.0 (t, JPC + JPC ) 9.3 Hz, PPh3-C3), 129.7, (t, JPC + JPC
)
42.6 Hz, PPh3-C1), 130.1 (s, PPh3-C4), 134.98 (t, 2JPC+4JPC ) 11.0
Hz, PPh3-C4), 179.5 (s, COOCH3), 352.0 (t, 2JPC ) 16.3 Hz, RudC);
IR (KBr) 1362 cm-1 (κ1-OCOsym), 1434 cm-1 (P-Ph), 1460 cm-1
(κ2-OCOsym), 1533 cm-1 (κ2-OCOasym), 1619 cm-1 (κ1-OCOasym),
1648 cm-1 (CdC), 3572 cm-1 (OH) ∆ν(uni) 257 cm-1, ∆ν(chelate) 73
cm-1; (CH2Cl2) 1366 cm-1 (κ1-OCOsym), 1435 cm-1 (P-Ph), 1459
cm-1 (κ2-OCOsym), 1539 cm-1 (κ2-OCOasym), 1623 cm-1 (κ1-
Acknowledgment. We are grateful to the EPRSC and
University of York for Funding (DTA Studentship to C.E.W.)
and to Mr. Robert Thatcher for assistance with X-ray
diffraction.
OCOasym), 1653 cm-1 (CdC), 3563 cm-1 (OH), ∆ν(uni) 257 cm-1
∆ν(chelate) 80 cm-1; MS (ESI), m/z 851.1612 [M]Na.
,
Supporting Information Available: Details of the X-ray
structure determination of compounds 1, 2a, 2c, and 3 in CIF
format. This material is available free of charge via the Internet at
http://pubs.acs.org.
Synthesis of Ru(K2-OAc)(K1-OAc)(PPh3)2(CO), 3. cis-Ru(κ2-
OAc)2(PPh3)2 (50 mg, 0.07 mmol) was suspended in 20 mL of
MeOH in a Schlenk tube equipped with a stirrer bar. The reaction
mixture was then placed under an atmosphere of CO and stirred
for 5 min. Over the course of this time the suspension changed
color from red to pale yellow. The product was isolated by filtration
and washed with 10 mL of MeOH and 10 mL of Et2O and dried in
Vacuo. Yield: 20 mg, 38.4%. NMR spectra CD2Cl2: 1H δH 0.64 (s,
6 H, COOCH3), 7.35-7.49 (m, 30 H, PPh3); 31P δP 39.1 (s, PPh3);
OM800950G
(40) Smart diffractometer control software (v5.625); Bruker-AXS, Bruker
AXS GmbH: Karlsruhe, Germany.
(41) Saint+ (v6.22); Bruker AXS, Bruker AXS GmbH: Karlsruhe,
Germany.
(42) Sheldrick, G. M. SHELXS-97, Program for the Solution of Crystal
Structures; Universita¨t Go¨ttingen, 1997.
(43) Sheldrick, G. M. SHELXL-97, Program for the Refinement of
Crystal Structures; Universita¨t Go¨ttingen, 1997.
3
5
13C δC 29.1 (s, COOCH3), 128.2 (t, JPC + JPC ) 9.7 Hz, PPh3-
C3), 130.0 (t, 1JPC + 3JPC ) 43.0 Hz, PPh3-C1), 130.3 (s, PPh3-C4),
134.7 (t, JPC + JPC ) 11.8 Hz, PPh3-C2), 181.4 (s, COOCH3),
2
4