Reactions of ruthenium(o) phosphine complexes with diphenylacetylene

Article abstract of DOI:10.1021/om0400954

Heating diphenylacetylene with [Ru(CO)₂(PPh₃) ₃] in toluene under reflux provides the 2-phenylindenone complex [Ru(η³=CCPh=CHC₆H₄)(CO)(PPh ₃)₂], arising from C-H activ

Full text of DOI:10.1021/om0400954

Organometallics 2004, 23, 5729-5736
5729
Reactions of Ruthenium(0) Phosphine Complexes with
Diphenylacetylene
Anthony F. Hill,* Madeleine Schultz, and Anthony C. Willis
Research School of Chemistry, Institute of Advanced Studies, Australian National University,
Canberra, Australian Capital Territory, Australia
Received July 7, 2004
Heating diphenylacetylene with [Ru(CO)2(PPh3)3] in toluene under reflux provides the
2-phenylindenone complex [Ru(η4-OdCCPhdCHC6H4)(CO)(PPh3)2], arising from C-H activa-
tion of one ortho-proton of diphenylacetylene, hydroruthenation of the triple bond, and
cyclization incorporating one carbonyl ligand. Both phosphines are replaced by 1,2-bis-
(diphenylphosphino)ethane to provide [Ru(η4-OdCCPhdCHC6H4)(CO)(dppe)]. In contrast,
heating diphenylacetylene with [Ru(CO)3(PPh3)2] in toluene under reflux generates the
tetraphenylcyclopentadienone complex [Ru(η4-OdCC4Ph4)(CO)2(PPh3)] in high yield, via
[2+2+1] alkyne and CO cyclization. The crystal structures of [Ru(η4-OdCCPhdCHC6H4)-
(CO)(PPh3)2], [Ru(η4-OdCCPhdCHC6H4)(CO)(dppe)], [Ru(η4-OdCC4Ph4)(CO)2(PPh3)], and
[Ru(η-PhCtCPh)(CO)2(PPh3)2] solvates are reported.
Introduction
complex to further discussions, we have acquired 13C-
{1H} and 31P{1H} NMR data in addition to placing the
compound on a firm structural footing through a crys-
tallographic analysis. Indeed, despite an enormously
rich chemistry of alkynes on ruthenium carbonyl clus-
ters,5 there exist remarkably few structural data for
simple mononuclear ruthenium(0) alkyne adducts, these
being limited to the complexes [Ru(η-F3CCtCCF3)-
(CO)4]6 and [Ru(η-PhCtCPh)(CO)2(PEt3)2],7 the latter
being most akin to 2. The geometry at ruthenium can
be deduced from the appearance of two ν(CO) IR
absorptions [Nujol: 1959, 1895 cm-1] and one 31P{1H}
NMR signal (δ ) 42.5, C6D6) as being trigonal bipyra-
midal with axial phosphines and the alkyne lying in the
equatorial plane to maximize retrodonation from the
π-basic ruthenium center. The trans disposition of the
phosphines is further confirmed by the characteristic
virtual triplets observed in the 13C{1H} NMR spectrum
for the carbon atoms (ipso, ortho/meta) of the PC6H5
groups. Infrared data for a range of complexes of the
form [Ru(L)(CO)2(PPh3)2] have been previously collated,8
and from these it is apparent that in this system PhCt
CPh is a weaker net acceptor ligand than a range of
carbon π-acids, such as CS2. The dichotomy between
alkynes acting as two- or four-electron donors is nor-
mally discussed in terms of the 13C{1H} NMR chemical
shifts of the alkyne carbon nuclei, because these are
known to be particularly sensitive to the electronic
environment. The alkyne carbon nuclei in 2 resonate
at δ ) 109.3, in a region typical of two-electron alkyne
ligands,9 to low field of that for free PhCtCPh (CDCl3:
δ ) 89.4).
The ruthenium(0) complex [Ru(CO)2(PPh3)3] (1) has
been shown to undergo facile substitution of one phos-
phine by diphenylacetylene to yield the simple alkyne
complex [Ru(η-PhCtCPh)(CO)2(PPh3)2] (2).1 A similar
reaction occurs with diphenylbutadiyne;2 however, with
the R,ω-diyne 4,7,10-trithiatrideca-2,11-diyne (TTDD)
remarkably facile (ambient conditions) co-cyclization of
the diyne with coordinated CO occurs to provide a
coordinated cyclopentadienone complex, [Ru{κ-S,η4-Od
C(CMe)CSC2H4)2S}(CO)(PPh3)] (3).3 In contrast, the
less labile starting material [Ru(CO)3(PPh3)2] (4) has
been reported to react with diphenylacetylene only in
refluxing benzene in the presence of carbon dioxide, to
form the coordinated tetraphenylcyclopentadienone com-
plex [Ru(η4-OdCC4Ph4)(CO)2(PPh3)] (5) apparently as
a mixture of isomers.4 Given this disparity in the
reaction conditions required for the formation of 3 and
5, the curious use of CO2 to activate 4, and the apparent
neglect of 2 as a mechanistic candidate en route to 5,
we have now reinvestigated the reactions of diphenyl-
acetylene with both 1 and 4. Under thermal conditions
(toluene reflux) these two compounds react very differ-
ently.
Results and Discussion
As reported by Roper,1 under ambient conditions the
complex 1 reacts cleanly with diphenylacetylene to
provide the zerovalent alkyne complex [Ru(η-PhCt
CPh)(CO)2(PPh3)2] (2). Given the importance of this
* To whom correspondence should be addressed. E-mail:
a.hill@anu.edu.au.
(5) Sappa, E. J. Cluster Sci. 1994, 5, 211-263.
(6) Marinelli, G.; Streib, W. E.; Huffman, J. C.; Caulton, K. G.;
Gagne´, M. R.; Takats, J.; Dartiguenave, M.; Chardon, C.; Jackson, S.
A.; Eisenstein, O. Polyhedron 1990, 9, 1867-1881.
(7) Ogasawara, M.; Maseras, F.; Gallego-Planas, N.; Kawamura, K.;
Ito, K.; Toyota, K.; Streib, W. E.; Komiya, S.; Eisenstein, O.; Caulton,
K. G. Organometallics 1997, 16, 1979-1993.
(1) Cavit, B. E.; Grundy, K. R.; Roper, W. R. J. Chem. Soc., Chem.
Commun. 1972, 60-61.
(2) Alcock, N. W.; Hill, A. F.; Melling, R. P.; Thompsett, A. R.
Organometallics 1993, 12, 641-648.
(3) Hill, A. F.; Rae, A. D.; Schultz, M.; Willis, A. C. Organometallics
2004, 23, 81-85.
(4) Yamazaki, H.; Taira, Z. J. Organomet. Chem. 1999, 578, 61-
67.
(8) Herberhold, M.; Hill, A. F. J. Organomet. Chem. 1990, 395, 195-
206.
10.1021/om0400954 CCC: $27.50 © 2004 American Chemical Society
Publication on Web 10/28/2004

5730 Organometallics, Vol. 23, No. 24, 2004
Hill et al.
formation of 5. Heating a toluene solution of 2 under
reflux in the presence of additional PhCtCPh also leads
to the formation of 6, as might be expected, in addition
to small amounts of 5. The compound 6 was also the
only tractable material isolated in small amounts from
the complex reaction mixture obtained from [Ru(CO)-
(CNC6H3Me2-2,6)(PPh3)3] and PhCtCPh under similar
conditions. The spectroscopic data for 6 did not un-
equivocally suggest a formulation for the product, in
part due to the complexity of the aryl region of both the
1H and 13C{1H} NMR spectra. Curiously, the infrared
spectrum included absorptions in regions typical of both
terminal [CH2Cl2: 1931] and ketonic carbonyl groups
[1583 cm-1]. The formulation of 6 as an indenone
complex, [Ru(η4-OdCCPhdCHC6H4)(CO)(PPh3)2], even-
tually followed from a crystallographic study, the results
of which are summarized in Figure 2. It is of note that
6 is a structural isomer of 2, with identical chemical
composition.
Figure 1. Molecular geometry of 2 in the crystal of 2‚C6H6
(40% probability ellipsoids, phenyl groups simplified).
Selected bond distances (Å) and angles (deg): Ru1-P1
2.3666(6), Ru1-P2 2.3718(6), Ru1-C1 1.901(2), Ru1-C2
1.906(2), Ru1-C9 2.159(2), Ru1-C10 2.161(2), C9-C10
1.273(3), P1-Ru1-P2 177.13(2), C1-Ru1-C2 108.0(1),
P1-Ru1-C1 93.47(7), P2-Ru1-C1 90.77(7), P1-Ru1-C2
89.16(7), P2-Ru1-C1 89.28(7), Ru1-C3-C9 141.0(2),
Ru1-C10-C11 141.3(2).
The geometry of the “Ru(CO)(PPh3)2” fragment of 6
is unremarkable, with parameters falling within con-
ventional norms for a piano-stool geometry.10-16 Some
steric congestion is expected with cis-PPh3 groups, and
the P1-Ru-P2 angle is 105.74(3)°. This congestion is
manifest in both the 31P{1H} NMR spectra and the
reactivity of the complex (see below). The germane
structural features concern the effect of coordination on
the indenone ligand. Free 2-phenyl-1-indenone17 has not
been structurally characterized; however the crystal
structure of 2,3-diphenyl-1-indenone18 provides a point
of reference for assessing the geometrical perturbations
accompanying complexation. Figure 3 displays struc-
tural data for the indenone skeletons of both 2,3-
diphenyl-1-indenone and 6 (ring numbering as for
Figure 2), and it is immediately apparent that the
somewhat localized bonds of the five-membered ring in
the free ligand become delocalized upon coordination to
the metal, the most dramatic change being to the bond
C(9)-C(10), which increases by 0.1 Å. In contrast, the
bonding in the six-membered benzo ring appears to
become more localized upon coordination relative to the
conventional aromatic nature of the benzo ring of free
The molecular structure of 2 is depicted in Figure 1,
which confirms the geometry suggested by spectroscopic
data. The geometry of the “Ru(CO)2(PPh3)2” fragment
calls for little comment, with interphosphine and inter-
carbonyl angles of 177.13(2)° and 108.0(1)°, respectively,
and Ru-P and Ru-C bond lengths that fall within
existing norms for ruthenium(0). Interest centers on the
alkyne ligand, data for which are presented in Table 1,
along with those for [M(η-F3CCtCCF3)(CO)4] (M ) Ru,
Os)6 and [Ru(η-PhCtCPh)(CO)2(PEt3)2].7 The ruthe-
nium π-basicity increases in the order RuL4 ) Ru(CO)4
< Ru(CO)2(PPh3)2 < Ru(CO)2(PEt3)2, and so it might be
expected that the geometric parameters for the alkyne
coordination in 2 would be intermediate, given simple
Dewar-Chatt-Duncanson arguments. However, the
replacement of PEt3 with the less basic PPh3 does not
result in statistically significant (3-4σ) changes in
either the CtC or Ru-C bond lengths. Structural data
for the perfluorobut-2-yne complex6 reveal significantly
shorter Ru-C bond lengths, though not at the expense
of the CtC bond; however it should be emphasized that
perfluorobut-2-yne is an exceptionally π-acidic and
poorly σ-basic alkyne. Thus, for the complexes in Table
1 it appears that the crystallographic data are insuf-
ficiently precise to assess the minimal geometric re-
sponse of subtle electronic variations in the ligand set
basicity.
Prolonged reflux of a toluene solution of 1 with excess
PhCtCPh results in a color change from pale yellow to
deep red and the formation of two major ruthenium-
containing products. The predominant product 6 pre-
cipitates from the reaction, and a minor product iden-
tified as 5 may be purified by column chromatography
(Scheme 1). The formation of 5 results from ligand
redistribution on ruthenium under these conditions and
is discussed further below. The major product 6 is
obtained in over 75% yield (both by 31P{1H} NMR
spectroscopy and isolated) upon heating a toluene
solution of preisolated 2 under reflux, with insignificant
(10) Structural data for piano stool complexes of the “fac-Ru(0)(CO)-
(PPh3)2” fragment are limited to the complexes [Ru(CO)(PPh3)2(L)] (L
) Me2Si(CHCH2)2 and H2CdCMeCHdO).12 Divalent examples in-
11
clude the neutral complex [Ru(CO)(PPh3)2(η5-C2B9H11)]13 and the
cationic examples [Ru(CO)(PPh3)2(L)]+ (L ) η-C5H514,15 and η5-C9H716).
For these complexes, Ru-P and Ru-C distances span the ranges
2.322-2.402 and 1.8331-1.890 Å, respectively, with the shorter Ru-C
distances being associated with the Ru(0) complexes and no obvious
correlation between Ru-P bond length and oxidation state or charge.
The P-Ru-P angles span the range 97.8-104.9°, while P-Ru-C
angles are generally smaller (86.1-97.8°). The angle-sums for the three
angles of each complex range from 280.5° to 296.7°, reflecting
geometries between pseudooctahedral and tetrahedral.
(11) Paulasaari, J. K.; Moiseeva, N.; Bau, R.; Weber, W. P. J.
Organomet. Chem. 1999, 587, 299-303.
(12) Hiraki, K.; Nonaka, A.; Matsunaga, T.; Kawano, H. J. Orga-
nomet. Chem. 1999, 574, 121-132.
(13) Ellis, D. D.; Couchman, S. M.; Jeffery, J. C.; Malget, J. M.;
Stone, F. G. A. Inorg. Chem. 1999, 38, 2981-2988.
(14) Doyle, G.; van Engen, D. J. Organomet. Chem. 1985, 280, 253-
259.
(15) Wisner, J. M.; Bartczak, T. J.; Ibers, J. A. Inorg. Chim. Acta
1985, 100, 115-123.
(16) Oro, L. A.; Ciriano, M. A.; Campo, M.; Foces-Foces, C.; Cano,
F. H. J. Organomet. Chem. 1985, 289, 117-131.
(9) For discussions of 13C{1H} NMR chemical shifts for coordinated
alkynes see: (a) Templeton, J. L. Adv. Organomet. Chem. 1989, 29,
1-100. (b) Cooke, J.; Takats, J. J. Am. Chem. Soc. 1997, 119, 11088-
11089. (c) Espuelas, J.; Esteruelas, M. A.; Lahoz, F. J.; Lo´pez, A. M.;
Oro, L. A.; Valero, C. J. Organomet. Chem. 1994, 468, 223-228.
(17) Free 2-phenylindenone is unstable with respect to pyrolytic
dimerization: Wawzonek, S.; Hansen, G. R.; Zigman, A. R. Chem.
Commun. 1969, 6.
(18) Watson, W. H.; Nagl, A. Acta Crystallogr. C 1987, 43, 2444-
2445.

Reactions of Ruthenium(0) Phosphine Complexes
Organometallics, Vol. 23, No. 24, 2004 5731
Table 1. Comparison of Geometric Parameters for Mononuclear Alkyne Complexes of Ruthenium
complex
R
R′
a
a′
b
[Ru(PhCtCPh)(CO)2(PEt3)2]7
[Ru(PhCtCPh)(CO)2(PPh3)2]
[Ru(F3CCtCCF3)(CO)4]6
[Os(F3CCtCCF3)(CO)4]6
138.0(2)
141.0(2)
145.4(3)
146.2(11)
139.4(2)
141.3(2)
145.3(3)
146.2(11)
2.1538(2)
2.159(2)
2.128(4)
2.149(12)
2.1538(2)
2.161(2)
2.121(4)
2.135(12)
1.286(3)
1.273(3)
1.276(6)
1.276(2)
Scheme 1. Reaction of [Ru(CO)2(PPh3)3] with
PhCtCPh in Refluxing Toluene (L ) PPh3)
Figure 2. Molecular geometry of 6 in the crystal of 6‚CH2-
Cl2 (40% probability ellipsoids, phenyl groups simplified).
Selected bond distances (Å) and angles (deg): Ru1-P1
2.3591(8), Ru1-P2 2.3522(7), Ru1-C1 1.825(3), Ru1-C3
2.382(3), Ru1-C4 2.456(3), Ru1-C9 2.163(3), Ru1-C10
2.268(3), O1-C1 1.161(4), O2-C2 1.241(3), C2-C4 1.492-
(4), C2-C10 1.470(4), C3-C4 1.419(4), C3-C8 1.423(4),
C3-C9 1.438(4), C4-C5 1.422(4), C5-C6 1.378(5), C6-
C7 1.411(5), C7-C8 1.366(5), C9-C10 1.450(4), P1-Ru1-
P2 105.74(3), C1-Ru1-P1 91.6(1), C1-Ru1-P2 87.8(1).
indenone. Thus, an alternation of long and short bonds
emerges around the C(3)-C(8) ring. These observations
presumably reflect significant involvement of the π-sys-
tem of the five-membered ring with the ruthenium
center at the expense of the aromaticity of the six-
membered ring, which develops 4,6-cyclohexadiene char-
acter. Notably, the 2-phenyl group is oriented so as to
allow conjugation with the indenone π-system.
The 31P{1H} NMR spectrum of 6 reflects its planar
chirality, such that two distinct resonances are observed
for the two diastereotopic phosphorus nuclei at all
temperatures (-80 to +100 °C) around δ 43 and 44.
However, rather than the anticipated AB system of two
doublets, the resonances appear as broad peaks at room
temperature (CDCl3: ν1/2 ) 70; CD2Cl2: ν1/2 ) 25;
(CDCl2)2: ν1/2 ) 85; C6D6: ν1/2 ) 100 Hz). Heating or
cooling the sample does not lead to resolution of the
coupling; the chemical shifts and line widths change
with temperature, while the resonances remain broad.
The broadness of these resonances is presumably re-
lated to synchronous rotation of the triphenylphosphine
ligands being sterically hindered by their adjacent
disposition. A plot of the 31P{1H} NMR spectra of 6 in
CD2Cl2 from -80 to 40 °C is shown in Figure 4, while
the corresponding plot in (CDCl2)2 from 25 to 100 °C is
included in the Supporting Information. In the 1H NMR
spectrum in CD2Cl2 at room temperature, the unique
olefinic proton is observed at δ 5.04. This appears as a
doublet (3J(PH) ) 4 Hz, 298 K), presumably showing
coupling only to the phosphorus atom that is pseudo-
trans to this proton, the implication being that the “Ru-
(CO)(PPh3)2” fragment does not freely rotate about the
axis normal to the indenone ligand plane. This reso-
nance broadens as the sample is heated or cooled. The
13C{1H} spectrum at room temperature displays reso-
nances for metal-bound (δ 210.1) and ketonic (δ 164.8)
carbonyl carbon nuclei, the former resonance showing
Figure 3. Schematic diagram showing the effects of metal
coordination upon the bond lengths in the 2-phenyl-1-
indenone fragment. The upper distances in italics are for
the free molecule, 2,3-diphenyl-1-indenone (R ) Ph),18
while the lower distances are for the coordinated ligand in
6 (R ) H; ring numbering as for Figure 2).
apparent triplet structure as expected due to coupling
to two inequivalent though similar phosphorus nuclei.
The mechanism by which 6 forms remains open to
speculation; however a plausible route is suggested in
Scheme 2. The alkyne complex 2 is stable at ambient
temperature, and so the requisite thermal activation is
presumably associated with the development of a vacant
coordination site via phosphine dissociation. Orthomet-
allation of one of the alkyne phenyl rings could then
generate a ruthenium(II) hydride complex. Examples
of the orthometalation of ligand aryl substituents are
numerous within the chemistry of ruthenium,19 athough

5732 Organometallics, Vol. 23, No. 24, 2004
Hill et al.
of such a role by alkynes is less well documented. The
haptotropic shift of [Os(NH3)5]n+ (n ) 2, 3) groups
between the CtC and ipso-ortho multiple bond of
diphenylacetylene is documented22 and provides an
alternative route for the ruthenium center to access the
ortho C-H bond, without requiring variations in valence
electron count (ligand dissociation). The 2-alkynylphenyl
class of ligand resulting from orthometalation has been
implicated on a number of occasions though no struc-
tural data exist for transition metal derivatives. Thus,
the insertion of benzyne into the metal-alkynyl bond
of [Ni(CtCPh)(CCldCCl2)(PEt3)2] has been invoked to
account for the resulting formation of ortho-PhCt
CC6H4CCldCCl2.23 A similar benzyne insertion mech-
anism has been suggested for the formation of PhCt
CC6H4SnBu3 from 2-Me3SiC6H4OTf and PhCtCSnBu3
catalyzed by [Pd2Cl2(η-C3H5)2].24 While these processes
appear to generate the 2-alkynylphenyl ligand, the
sequence is distinct from that proposed en route to 6.
However, such an activation has been suggested for the
formation of the complex tentatively formulated as [Co-
(σ,η2-C6F4CtCPh-2){η4-OdCC4Ph2(C6F5)2}], arising from
the thermolysis of [Co2(PhCtCC6F5)(CO)6].25
Figure 4. 31P{1H} NMR spectra of 6 in CD2Cl2 over the
temperature range -80 to +40 °C.
Scheme 2. Suggested Mechanism for the
Formation of 6 (L ) PPh3)
The remaining steps in the mechanistic proposal
involve migratory insertion of a carbonyl ligand, alkyne
hydroruthenation to generate a metallacyclic alkenyl
complex, and reductive elimination of the indenone
ligand. None of these steps are contentious; however two
points are noteworthy: First, we have no evidence as
to whether alkyne hydrometalation precedes or follows
carbonyl insertion. Second, in the vast majority of cases
alkyne hydroruthenation proceeds via a concerted mech-
anism to place Ru and H in cis positions on the resulting
alkene. Products resulting from the addition regiochem-
istry A in Scheme 2 are not observed, so if hydroruth-
enation with this regiochemistry occurs, it must be
reversible. A mechanism involving concerted cis addition
with the regiochemistry inferred from the structure of
the product 6 leads to an energetically unfavorable,
strained trans cyclohexene structure. Instead, it is
necessary to invoke a σ,π (three-electron) vinyl coordi-
nation (B in Scheme 2), with attendant geometric (and
entropic) demands. In the event that carbonyl insertion
precedes alkyne hydrometalation, a greater degree of
conformational flexibility is introduced, easing access
to this otherwise strained alkyne insertion transition
state.
An iron compound with an indenone ligand related
to that of 6 has been observed in low yield as one of a
mixture of six products obtained from the reaction of
bis(4-chlorophenyl)acetylene with Fe3(CO)12 in refluxing
petroleum (bp 80 °C) (Scheme 3).26 When the same
reaction was carried out with unsubstituted PhCtCPh,
none of the corresponding 2-phenylindenone complex
was detected in the product mixture.27 Further litera-
ture precedent for orthometalation of diphenylacetylene
by far the majority involve the aryl group being tethered
to a classical donor, e.g., phosphines, azobenzenes,
bipyridyls, and phosphites. Indeed, the intermediacy of
orthometalated phosphines in catalytic hydrogenations
mediated by [RuHCl(PPh3)3] has long been recognized.20
More recently, Murai has shown that acyl groups may
serve to tether aryl groups proximal to ruthenium for
the purpose of orthometalation;21 however, the adoption
(22) Harman, W. D.; Wishart, J. F.; Taube, H. Inorg. Chem. 1989,
28, 2411-2413.
(23) Miller, R. G.; Kuhlman, D. P. J. Organomet. Chem. 1971, 26,
401-406.
(19) Hill, A. F. In Comprehensive Organometallic Chemistry; Abel,
E. W., Stone, F. G. A., Wilkinson, G., Eds.; Elsevier Science Ltd:
Oxford, 1995; Vol. 7.
(20) James, B. R.; Markham, L. D.; Wang, D. K. W. J. Chem. Soc.,
Chem. Commun. 1974, 439-440.
(21) Murai, S.; Chatani, N.; Kakiuchi, F. Pure Appl. Chem. 1997,
69, 589-594.
(24) Yoshida, H.; Honda, Y.; Shirakawa, E.; Hiyama, T. Chem.
Commun. 2001, 1880-1881.
(25) Dickson, R. S.; Michel, L. J. Aus. J. Chem. 1975, 28, 1957-
1969.
(26) Braye, E. H.; Hu¨bel, W. J. Organomet. Chem. 1965, 3, 38-42.
(27) Hu¨bel, W.; Braye, E. H. J. Inorg. Nucl. Chem. 1959, 10, 250-
268.

Reactions of Ruthenium(0) Phosphine Complexes
Organometallics, Vol. 23, No. 24, 2004 5733
Scheme 3. Reported Reaction of
Bis(4-chlorophenyl)acetylene with Fe3(CO)12
26
Figure 5. Molecular geometry of 7 in the crystal of 7‚CH2-
Cl2 (40% probability ellipsoids, phenyl groups simplified).
Selected bond distances (Å) and angles (deg): Ru1-P1
2.315(2), Ru1-P2 2.307(2), Ru1-C1 1.86(1), Ru1-C3
2.279(9), Ru1-C4 2.344(9), Ru1-C9 2.173(7), Ru1-C10
2.271(9), O1-C1 1.14(1), O2-C2 1.26(1), C2-C4 1.51(1),
C2-C10 1.46(1), C3-C4 1.41(1), C3-C8 1.43(1), C3-C9
1.44(1), C4-C5 1.45(1), C5-C6 1.37(1), C6-C7 1.41(1),
C7-C8 1.37(1), C9-C10 1.45(1), P1-Ru1-P2 83.07(9),
P1-Ru1-C1 89.7(3), P2-Ru1-C1 88.0(3).
is provided by the formation 2-phenylindanone from
PhCtCPh, CO, and water catalyzed by a mixture of
[Co2(CO)8] and PPh3, for which intermediate cobaltain-
dene and indenone complexes were proposed.28 A similar
orthometalation is implicit in the aryl indenone forma-
tion arising from the reaction of PhCtCPh with [Fe(2-
chlorophenyl)(CO)2(η-C5H5)].29 Notably, earlier work by
Hu¨bel and co-workers demonstrated that a diferrain-
dene did not react with CO up to 250 °C under CO
pressure to form the coordinated indenone (Scheme 3).26
Rhoda-30 and ruthenaindenes31 have similarly been
obtained from PhCtCPh, though in neither case do
subsequent insertion or elimination processes ensue.
When 2 was heated in an NMR tube in d8-toluene,
after 5 min at reflux the 31P{1H} resonance due to 2
was observed in addition to resonances attributable to
[Ru(CO)2(PPh3)3] 1 and [Ru(CO)3(PPh3)2] 4 (approxi-
mate ratio 1:2:4 1:10:5). After 18 h heating under reflux,
the characteristic broad resonances due to the indenone
complex 6 were observed, as well as a minor resonance
at δ 38 corresponding to the tetraphenylcyclopentadi-
enone complex 5. This last complex is presumably
formed from the reaction of PhCtCPh with 4, the latter
arising from ligand redistribution (see below). A minor
and as yet unidentified resonance was observed at δ 47.
Further heating did not alter the 31P{1H} spectrum of
the reaction mixture, which contained 5, 6, 4, and 1 in
the approximate ratio 1:20:1:2. In contrast, heating a
mixture of 2 and PhCtCPh in d6-benzene under reflux
(bp ca. 79 °C) did not result in appreciable formation of
5 or 6 but rather led to the eventual accumulation of 4,
which is presumably the thermodynamic minimum of
possible ligand redistribution products of the starting
material.
that the peculiarities in the spectrum of 6 were due to
hindered rotation about the Ru-P bonds (entirely
precluded for 7). These values may be compared with
that reported for the complex [Ru{η4-OdC(MeCCSC2H4)2-
S}(CO)(dppe)] (C6D6: δ ) 60.5),3 which in contrast to
7, has a molecular plane of symmetry. Complex 7 was
also characterized crystallographically, and the results
of this study are summarized in Figure 5. The geometric
parameters for the indenone ligand are comparable to
those for 6, again reflecting the development of cyclo-
hexadiene character for the benzo ring, which lodges in
the cleft provided by the two phosphine phenyl groups
positioned anti to the carbonyl ligand. The remaining
phenyl group bound to P1 lies between the indenone
carbonyl and the 2-phenyl substituents, but remains in
an orientation allowing conjugation with the indenone
system. Each of these placements appears to arise from
a minimization of interligand steric interactions since
there are no obvious intramolecular C-H‚‚‚π or π-stack-
ing interactions. The strength of indenone coordination
in both 6 and 7 is noteworthy in that no [Ru(CO)-
(dppe)2]32 was observed during the reaction, and neither
does 6 react with carbon monoxide under mild condi-
tions (ambient temperature, 1 atm).
The alternative ruthenium(0) starting material 4 is,
in contrast to 1, essentially inert to ligand substitution
under ambient conditions. However, when treated with
excess PhCtCPh in refluxing toluene over 2 weeks, a
[2+2+1] cyclization of CO and alkyne is observed to
provide the tetraphenylcyclopentadienone adduct 5 in
good yield (85% by 31P{1H} NMR). This contradicts the
reported and curious requirement of CO2 for the reac-
tion to occur,4 an observation that was rationalized in
terms of the supposed formation of [Ru(CO)4(PPh3)2]O2-
CO among other intriguing mechanistic candidates. Of
more concern are inconsistencies between the spectro-
scopic data we obtained for 5 and those previously
The product 6 reacts with 1,2-bis(diphenylphosphino)-
ethane (dppe) in refluxing toluene to substitute both
triphenylphosphine ligands and form the corresponding
dppe complex [Ru(η4-OdCC6H4CHdCPh)(CO)(dppe)]
(7), which is noticeably more soluble than 6. Spec-
troscopic data for the derivative are as expected, and
most notably the 31P{1H} NMR spectrum comprises a
simple conventional AB system [CD2Cl2: δ ) 76.5, 60.6;
2J(PAPB) ) 3.2 Hz], lending credence to our assumption
(28) Joh, T.; Doyama, K.; Fujiwara, K.; Maeshima, K.; Takahashi,
S. Organometallics 1991, 10, 508-513.
(29) Butler, I. R.; Cullen, W. R.; Lindsell, W. E.; Preston, P. N.;
Rettig, S. J. J. Chem. Soc., Chem. Commun. 1987, 439-441.
(30) Werner, H.; Wolf, J.; Schubert, U.; Ackermann, K. J. Orga-
nomet. Chem. 1986, 317, 327-356.
(31) Burns, R. M.; Hubbard, J. L. J. Am. Chem. Soc. 1994, 116,
9514-9520.
(32) Roper, W. R.; Wright, L. J. J. Organomet. Chem. 1982, 234,
C5-C8.

5734 Organometallics, Vol. 23, No. 24, 2004
Hill et al.
Scheme 4. Suggested Mechanism for the
Formation of 5 (L ) PPh3)
Figure 6. Molecular geometry of 5 in the crystal of 5‚C7H8
(40% probability ellipsoids, phenyl groups simplified).
Selected bond distances (Å) and angles (deg): Ru1-P1
2.3673(7), Ru1-C2 2.268(2), Ru1-C3 2.203(2), Ru1-C4
2.204(2), Ru1-C5 2.280(2), Ru1-C6 1.884(3), Ru1-C7
1.891(3), C1-O1 1.240(3), C6-O6 1.151(3), C7-O7 1.146-
(3), C1-C2 1.488(3), C1-C5 1.481(3), C2-C3 1.452(3), C3-
C4 1.411(3), C4-C5 1.444(3), P1-Ru1-C6 91.16(8), P1-
Ru1-C7 90.99(8), C6-Ru1-C7 93.9(1).
reported.4,33 Because of these uncertainties, an X-ray
structural determination was performed to confirm the
identity of the product. The structure of 5‚C6H6 was
published; the present study used crystals of 5‚PhMe
obtained from toluene. The results of this study are
summarized in Figure 6. In the previous study 5 was
reported to form as a mixture of isomers arising from
rotation of the “Ru(CO)2(PPh3)” group about an axis
normal to the cyclopentadienone plane, though it might
be expected that such a rotation is rapid. We, however,
observe only one isomer with δ(31P) ) 38.9 and ν(CO)
) 2012 and 1958 cm-1 (toluene). It is implausible that
two isomers would be distinctly observable on the NMR
time scale but not on the infrared time scale. Germane
geometric parameters associated with the cyclopenta-
dienone of both 5‚C6H6 and 5‚PhMe are, as expected,
comparable and fall within norms for such ligands
bound to ruthenium.3,4,34-36 The general impact of
coordination of the cyclopentadienone ring may be
assessed with reference to the crystal structure of free
tetraphenylcyclopentadienone,37 the primary perturba-
tion being that the CdC and C-C bond lengths within
the butadiene component of the cyclopentadienone ring
become more similar as a result of association of the
π-system with the ruthenium center.
“Ru(CO)3(PPh3)” fragment would then provide [Ru(η-
PhCtCPh)(CO)3(PPh3)]. This complex differs from 4 in
having an extra π-acceptor ligand, which might be
expected to activate the complex to migratory insertion
involving coupling of the alkyne with one carbonyl
ligand (path D). Some support for this interpretation
comes from the observation that the thiocarbonyl com-
plex [Os(η-PhCtCPh)(CS)(PPh3)2] reacts with carbon
monoxide to provide the osmacyclobutenthione complex
[Os{C(dS)CPhdCPh}(CO)2(PPh3)2],38 via CS/alkyne cou-
pling of the presumed intermediate [Os(η-PhCtCPh)-
(CS)(CO)(PPh3)2]. Formation of the ruthenacyclobuten-
one depletes the ruthenium center of two valence
electrons, which allows coordination of a second alkyne
unit that then inserts into the ruthenium alkenyl
linkage. Santos has shown that activated alkynes insert
into nonmetallacyclic coordinatively unsaturated ru-
thenium alkenyls.39,40 More relevant to the present
situation, the formation of the metallacyclohexadienes
[Ru{C(dCHR)CRdCHCRdCH}(CO)(PPh3)2] (R ) CO2-
Me)41 and [Os{C(dS)CHdCHCHdCH}(CO)(PPh3)2]42
may be interpreted in terms of alkyne insertion into the
metal alkenyl bonds of the metallacyclobutene inter-
mediates [Ru{C(dCHR)CRdCH}(CO)(PPh3)2] and [Os-
{C(dS)CHdCH}(CO)(PPh3)2]. In both of these cases, the
metallacyclohexadiene ring is stabilized by a further
interaction (sulfur or ester) with the metal center and
reductive elimination does not proceed under the reac-
tion conditions. In the present case, however, no such
Two alternative mechanisms for the formation of 5
are proposed in Scheme 4. The starting complex 4 is
relatively unreactive, in contrast to 1, but in refluxing
toluene, must lose either one carbonyl or one triphen-
ylphosphine ligand. Because neither 6 nor 2 is observed
in the reaction of 4 with PhCtCPh, the ligand lost
appears to be PPh3. Coordination of the alkyne to the
(33) Most notably, the 31P{1H} NMR resonance reported for one of
the suggested isomers of 5 (δ ) 26.5) is identical with that for
triphenylphosphine oxide.
(38) Elliot, G. P.; Roper, W. R. J. Organomet. Chem. 1983, 250, C5-
C8.
(34) Blum, Y.; Shvo, Y.; Chodosh, D. F. Inorg. Chim. Acta 1985, 97,
L25-L26.
(39) Torres, M. R.; Santos, A.; Ros, J.; Solans, X. Organometallics
1987, 6, 1091-1095.
(35) Smith, T. P.; Kwan, K. S.; Taube, H.; Bino, A.; Cohen, S. Inorg.
Chem. 1984, 23, 1943-1945.
(40) Castan˜o, A. M.; Echavarren, A. M.; Lo´pez, J.; Santos, A. J.
Organomet. Chem. 1989, 379, 171-175.
(36) Ru¨ba, E.; Mereiter, K.; Soldouzi, K. M.; Gemel, C.; Schmid, R.;
Kirchner, K.; Bustelo, E.; Puerta, M. C.; Valerga, P. Organometallics
2000, 19, 5384-5391.
(41) Yamazaki, H.; Aoki, K. J. Organomet. Chem. 1976, 122, C54-
C58; the same compound was obtained in low yield from a different
route: Bruce, M. I.; Hall, B. C.; Skelton, B. W.; Tiekink, E. R. T.; White,
A. H.; Zaitseva, N. N. Aus. J. Chem. 2000, 53, 99-107.
(42) Elliot, G. P.; Roper, W. R.; Waters, J. M. J. Chem. Soc., Chem.
Commun. 1982, 811-813.
(37) Alvarez-Toledano, C.; Baldovino, O.; Espinoza, G.; Toscano, R.
A.; Gutie´rrez-Pe´rez, R.; Garc´ıa-Mellado, O. J. Organomet. Chem. 1997,
540, 41-49.

Reactions of Ruthenium(0) Phosphine Complexes
Organometallics, Vol. 23, No. 24, 2004 5735
service of the Research School of Chemistry, Australian
National University.
interaction is possible, and thus reductive elimination
of the cyclopentadienone occurs.
Synthesis of [Ru(η-PhCtCPh)(CO)2(PPh3)2]1 (2). The
complex was prepared as described previously. A mixture of
[Ru(CO)2(PPh3)3] (1: 1.5 g, 1.6 mmol) and diphenylacetylene
(0.60 g, 3.4 mmol) in toluene was stirred overnight under a
nitrogen atmosphere. Completion of the reaction was evident
by the disappearance of the infrared absorption at 1900 cm-1
and appearance of bands at 1959 and 1891 cm-1. The solvent
volume was reduced under reduced pressure and the residue
crystallized from a mixture of toluene and hexane. Yield: 1.2
g (88%). Crystallographic grade crystals of the benzene mono-
solvate were obtained by slow evaporation of a benzene
We have no firm evidence to exclude the alternative
sequence of events represented in path C, viz., coordi-
nation of two alkynes followed by cyclization to a
ruthenacyclopentadiene, which then inserts a CO ligand.
However, the only route to a coordinatively unsaturated
intermediate for coordination of the second alkyne
would require dissociation of either a second phosphine
or carbonyl ligand to provide [Ru(η-PhCtCPh)(CO)x-
(PPh3)3-x] (x ) 2, 3). It should be noted that the ability
of alkynes to act as four-electron donors does provide a
mechanism for stabilization of such intermediates, a
situation that has been addressed by Caulton in related
systems.6,7
The observation of 5 from the reaction of 1 with
PhCtCPh is presumably due to the initial formation
of some 4 (observed spectroscopically) through ligand
redistribution under the harsh reaction conditions.
Notably, 1 reacts immediately with CO (1 atm) to form
4 quantitatively. Comparing the mechanisms proposed
in Schemes 2 and 4, it is apparent that the significant
difference between these two reactions is the “(CO)2-
(PPh3)2” versus “(CO)3(PPh3)” ligand sets. Given that
the reactions are both high yielding, and form only the
product described regardless of the stoichiometry of the
reagents, common intermediates may be excluded.
Thus, the electronic nature of the fragment “Ru(CO)2-
(PPh3)2” is fundamentally different to that of “Ru(CO)3-
(PPh3)”.
solution of the complex. IR C6H6: 1963, 1875 (RuCO) cm-1
.
Nujol: 1959, 1895 (RuCO), 1777 (CtC) cm-1. NMR (C6D6, 298
1
K) H (300 MHz): δ 7.71 (m, 12 H), 7.28 (m, 2 H), 7.26 (m, 2
H), 6.97-6.87 (m, 24 H). 13C{1H} (75.5 MHz): δ 135.7 [vt, JCP
) 21, C1(PC6H5)], 134.3 [vt, JCP ) 6, C2,3(PC6H5)], 131.9 [s, C4-
(C6H5)], 130.9 [s, C2,3(C6H5)], 129.6 [s, C2,3(C6H5)], 124.9 [s, C1-
(C6H5)], 109.3 (t, 2JCP ) 4 Hz, CtC); other peaks obscured by
solvent peak. 31P{1H} (121 MHz): 42.5 (s). Crystal data for
2‚C6H6: C58H46O2P2Ru, Mw ) 938.02, triclinic, P1h (#2), a )
11.5764(1) Å, b ) 13.5638(2) Å, c ) 16.9036(2) Å, R ) 82.5692-
(5)°, â ) 72.9256(6)°, γ ) 66.1848(6)°, V ) 2321.00(5) Å3, Z )
2, Fcalc ) 1.342 g cm-3, T ) 200 K, yellow block, 11 423
independent measured reflections [2θ e 55°], R1 ) 0.0319, wR2
) 0.0366, 7616 absorption-corrected reflections [I > 3σ(I)], 568
parameters, CCDC 237864.
Synthesis of [Ru{η4-(OC(CPh)4}(CO)2(PPh3)] (5). The
complex [Ru(CO)3(PPh3)2] (4) (0.010 g, 1.4 × 10-2 mmol) and
PhCtCPh (0.075 g, 4.2 × 10-2 mmol) were weighed into a
flask, and toluene was added. The mixture was heated to reflux
until the 31P{1H} spectrum indicated complete consumption
of 4 (2 weeks). Slow evaporation of the solvent led to the
formation of X-ray quality crystals of 5, which crystallized with
one molecule of toluene in the lattice. The complex 5 can also
be obtained by chromatography (SiO2, THF) of the supernatant
of the reaction of [Ru(CO)2(PPh3)3] with excess PhCtCPh in
refluxing toluene (see below). IR toluene: 2012, 1958 (RuCO),
1613 (CdO) cm-1 (cf 2011, 1956, and 16064). 31P{1H} NMR
(CD2Cl2, 298 K, 121 MHz): δ 38.9 (s) (cf δ 26.5, 32.74 NB:
OPPh3 has δ ) 26.5). Crystal data for 5‚C7H8: C56H43O3PRu,
Mw ) 895.94, monoclinic, P21/n (#14), a ) 12.871(3) Å, b )
18.419(4) Å, c ) 18.401(4) Å, â ) 95.94(3)°, V ) 4338(1) Å3, Z
) 4, Fcalc ) 1.372 g cm-3, T ) 200 K, yellow block, 9929
independent measured reflections [2θ e 55°], R1 ) 0.0382, wR2
) 0.0864, 7477 absorption-corrected reflections [I > 2σ(I)], 551
parameters, CCDC 237866.
Synthesis of [Ru(CO)(PPh3)2{η4-(OdC(Ph)CC(H)C6H4}]
(6). (a) A mixture of [Ru(CO)2(PPh3)3] (1: 2.15 g, 2.27 mmol)
and PhCtCPh (1.21 g, 6.80 mmol) in toluene (50 mL) was
heated under reflux for 2 days, during which time the color
changed from yellow to deep red. The reaction was monitored
by 31P{1H} NMR spectroscopy, which revealed that after 2
days, no further product (toluene/C6D6 δ ) 42, 43) was formed
and that the starting ruthenium complex 1 (δ 50.9) had been
completely consumed. Upon cooling to room temperature, 6
precipitated as an orange solid. The supernatant was chro-
matographed on silica gel, eluting initially with dichlo-
romethane to remove triphenylphosphine and its oxide, and
subsequently eluting with tetrahydrofuran to give the byprod-
uct 5 (0.20 g). The orange solid was recrystallized from
dichloromethane to provide an orange powder of the dichlo-
romethane monosolvate of 6. Mp: 178-180 °C. Crystal-
lographic grade crystals of the dichloromethane solvate were
grown by the slow evaporation of a solution of the complex in
dichloromethane. Yield: 0.88 g (44%). (b) A solution of [Ru-
(η-PhCtCPh)(CO)2(PPh3)2] (2: 2.4 g, 2.79 mmol) in toluene
(300 mL) was heated under reflux in an atmosphere of
prepurified nitrogen for 3 days. The complex 6 was isolated
by column chromatography, eluting first with dichloromethane
Conclusions
The thermal reactions of the two ruthenium(0) start-
ing materials 1 and 4 with excess diphenylacetylene
both proceed in good yield, forming dramatically differ-
ent products, both of which contain Ru(0). The former
reaction proceeds via the alkyne adduct 2, which
undergoes an ortho-C-H activation reaction to subse-
quently deliver this hydrogen atom to the alkyne triple
bond. Reductive elimination leads to the coordinated
indenone complex 6. In contrast, 4 reacts via carbonyl
and alkyne coupling with reductive elimination of a
tetraphenylcyclopentadienone fragment to yield the
complex 5. Common intermediates can be excluded,
leading to the inference that the electronic properties
of the “Ru(CO)x(PPh3)4-x” (x ) 2, 3) fragments are
sufficiently distinct to direct the course of the reactions
profoundly.
Experimental Section
General Procedures. All air-sensitive manipulations were
carried out under a dry, oxygen-free nitrogen atmosphere using
standard Schlenk and vacuum line techniques, using dried and
degassed solvents. NMR spectra were recorded on a Varian
Inova 300 (1H at 300.75, 13C at 75.4, 31P at 121.4 MHz)
instrument. The chemical shifts (δ) for 1H and 13C{1H} spectra
are given in ppm relative to residual signals of the solvent
and for 31P{1H} spectra to an external 85% H3PO4 reference.
The coupling constants (J) are given in Hz with an estimated
error of (0.5 Hz. Mass spectra of the complexes were obtained
on a Micromass ZMD spectrometer using the APCI technique
in acetonitrile by the Mass Spectrometry service of the
Research School of Chemistry, Australian National University.
The microanalyses were carried out by the microanalytical

5736 Organometallics, Vol. 23, No. 24, 2004
Hill et al.
to remove triphenylphosphine and its oxide, then with THF
to remove 6 (no 5 is formed under these conditions). Yield:
1.80 g (75%). IR Nujol: 1925s (RuCO), 1595m, 1581m (CdO);
CH2Cl2: 1931s (RuCO), 1583brm (CdO) cm-1. NMR (CD2Cl2,
298 K) 1H (300 MHz): δ 8.22 [d, 2 H, 3JHH ) 11, (C6H4)], 7.47-
7.15, 6.90-6.75 [m × 2, 35 H, PC6H5 and (CC6H5)], 6.26 [d,
3JHP ) 8, 1 H, (C6H4)], 5.95 [br, 1 H, (C6H4)], 5.04 [d, 3JHP ) 4
Hz, 1 H, (PhCdCH)]. 13C{1H} (75 MHz): δ 210.1 (dd, M-CO,
orange microcrystals. Yield: 0.13 g (71%). Mp: 150-155 °C
(dec). Crystallographic grade crystals of the dichloromethane
monosolvate were obtained by slow diffusion of hexane into a
dichloromethane solution. IR CH2Cl2: 1943s (RuCO), 1585m
1
(CdO) cm-1. NMR (CD2Cl2, 298 K) H (300 MHz): δ 7.91 [d,
3
2 H, H2,6(CC6H5), JHH ) 7.2], 7.73-7.61, 7.51 (m × 2, 10 H,
PC6H5), 7.37-7.07 (m, 12 H, PC6H5 and CC6H5), 6.62 [d, 1 H,
H4/7(C6H4), 3JHH ) 8.4], 6.39 [dd, 2 H, H2,6(PC6H5), 3JHP ) 3JHH
) 7.8] 6.20, 6.11 [t, × 2, 2 H × 2, H5,6(C6H4), 3JHH ) 7.4], 5.68
(d, 1 H, 3JHP ) 2.7 Hz, H3(OdCC4)], 2.68-1.93 (m × 2, 4 H ×
2, PCH2).13C{1H} (121 MHz): δ 205.8 (br, RuCO), 164.8 (CO),
2JPAC ) 2JPBC ) 12), 164.8 (OdC), 138.1 [C4(CC6H5)], 136.5,
1
135.4 [d × 2, C1(PC6H5), JCP ) 60], 134.2, 133.9 [d × 2, C3,5
-
(PC6H5), 3JCP ) 14], 131.4 (s, C6H4), 129.8 [d, C2,6(PC6H5), 2JCP
) 28], 129.2 [d, C2,6(PC6H5), 2JCP ) 23] 128.69, 128.43, 128.32,
128.22, 128.14, 129.09, 127.8 (8 lines, PC6H5, C6H4 and CC6H5),
127.3 [s, C2,6(CC6H5)], 127.1 (s, C6H4), 125.8, 125.5 [C4(PC6H5)],
125.2 (CC6H5), 124.9, 121.2 (s, C6H4), 110.5 (CC6H5), 92.0 [br
x 2, C8,9(OdCC4)], 77.4 [dd, 2JCP ) 8, 2JCP ) 3 Hz, C2(OdCC4)],
64.0 [br, C3(OdCC4)]. 31P{1H} (121 MHz): δ 44.5 (br), 43.0 (br).
MS (APCI, +ve ion): 861 [M]+. Anal. Satisfactory data not
obtained, presumably due to desolvation. Found: C, 67.96; H,
4.74; P, 6.35. Calcd for C52H40O2P2Ru‚CH2Cl2: C, 67.37; H,
4.48; P, 6.56. Crystal data for 6‚CH2Cl2: C53H42Cl2O2P2Ru, Mw
) 944.78, monoclinic, P21/n (#14), a ) 10.2089(1) Å, b )
19.1137(2) Å, c ) 22.0738(2) Å, â ) 93.636(1)°, V ) 4298.59-
(7) Å3, Z ) 4, Fcalc ) 1.460 g cm-3, T ) 200 K, orange block,
1
137.1 [C1(CC6H5)], 135.3 [d, JCP ) 49, C1(PC6H5)], 134.8 [d,
1JCP ) 40, C1(PC6H5)], 133.8 [d, 2JCP ) 11, C2,6(PC6H5)], 133.5
[C4(PC6H5)], 132.8, 132.3 [d × 2, 3JCP ) 11, C3,5(PC6H5)], 132.1
[d, 2JCP ) 15, C2,6(PC6H5)], 131.1 [C4(PC6H5)], 130.5, 129.4 [C5,6
-
3
(C6H4)], 128.8, 128.6 [d × 2, JCP ) 7, C3,5(PC6H5)], 128.1 [C4-
(PC6H5)], 127.9 [d, 3JCP ) 10, C3,5(PC6H5)], 126.5, 125.6, 125.2
[C2-6(CC6H5)], 123.2, 120.7 [C4,7(C6H4)], 105.6, 93.5[C8,9(Od
1
CC4)], 76.9 [br, C2(OdCC4)], 61.0 [C3(OdCC4)], 30.6 (dd, JCP
2
1
2
) 46, JCP ) 13, PCH2), 29.6 (dd, JCP ) 32, JCP ) 13 Hz,
PCH2). 31P{1H} (121 MHz): δ 76.5, 60.6 (AB, JAB ) 3.2 Hz).
2
MS (APCI, +ve ion): 734 [M]+, 706 [M - CO]+. Anal. Found:
C, 68.48; H, 4.33; P, 8.44. Calcd for C42H34O2P2Ru: C, 68.75;
H, 4.67; P, 8.44. Crystal data for 7‚CH2Cl2: C43H36Cl2O2P2Ru,
Mw ) 818.68, monoclinic, P21/n (#14), a ) 13.0957(5) Å, b )
21.3537(9) Å, c ) 14.4418(6) Å, â ) 100.305(2)°, V ) 3973.4-
(3) Å3, Z ) 4, Fcalc ) 1.368 g cm-3, T ) 200 K, orange plate,
9864 independent measured reflections [2θ e 55°], R1
)
0.0448, wR2 ) 0.1092, 8116 absorption-corrected reflections
[I > 2σ(I)], 541 parameters, CCDC 237863.
Synthesis of [Ru(CO)(dppe){η4-(OC(Ph)CC(H)C6H4}]
(7). A mixture of [Ru{η4-(OCCPhdCHC6H4)(CO)(PPh3)2] (6:
0.22 g, 0.25 mmol) and 1,2-bis(diphenylphosphino)ethane (0.20
g, 0.50 mmol) in toluene (40 mL) was heated under reflux. The
reaction progress was monitored by infrared spectroscopy,
which indicated that after 2 h all the starting material (ν(CO)
) 1931 cm-1) had been converted to 7 (ν(CO) ) 1943 cm-1).
The solvent was removed under reduced pressure, and the
residue was washed with benzene to remove triphenylphos-
phine and unreacted dppe. The residue was then crystallized
from a mixture of dichloromethane and hexane to provide
5513 independent measured reflections [2θ e 46°], R1
)
0.0572, wR2 ) 0.0511, 2645 absorption-corrected reflections
[I > 1.5σ(I)], 451 parameters, CCDC 237865.
Supporting Information Available: Tables giving crys-
tallographic details for 2, 5, 6, and 7; stacked plot of 31P{1H}
NMR spectra of 6 in C2D2Cl4 from 25 to 100 °C. This material
is available free of charge via the Internet at http://pubs.acs.org.
OM0400954