Linking of benzyne and carbon monoxide at a triruthenium centre by migratory insertion

Article abstract of DOI:10.1016/S0022-328X(98)00448-3

The μ₃-benzyne complex [Ru₃(CO)₇(μ-PPh₂)₂(μ₃-C₆H₄)] (1a) reacts at room temperature (r.t.) with carbon monoxide (1 atm), trimethylphosphite, or t-butylisocyanide to give complexes [Ru₃(CO)₆L₂(μ-PPh₂)₂(μ₃-C₆H₄CO)] (2a, L=CO; 2b, L=P(OMe)₃; 2c, L=^tBuNC) containing an ortho-metallated μ₃-benzoyl ligand. Studies with ¹³CO confirm that the reaction involves a migratory insertion of CO into a benzyne-CO σ-bond. The μ₃-benzoyl products are formed exclusively when a large excess of the π-acceptor ligand is used, but at lower concentrations substitution of CO by the incoming ligand also occurs to give the complexes [Ru₃(CO)₆L(μ-PPh₂)₂(μ₃-C₆H₄)] [1b, L=P(OMe)₃; 1c, L=^tBuNC]. Although ¹³C-labelling studies show that the reaction of 1a with CO is irreversible at r.t., it is readily reversed by warming complex 2a in hexane. No reaction occurs at r.t. between complex 1a and triphenylphosphine or tri-isopropylphosphine, but on heating in toluene the phosphine-substituted complexes [Ru₃(CO)₆(PR₃)(μ-PPh₂)₂(μ₃-C₆H₄)] (1d, R=Ph; 1e,R=ⁱPr) are formed, which upon carbonylation give complexes [Ru₃(CO)₇(PR₃)(μ-PPh₂)₂(μ₃-C₆H₄CO)] (2d, R=Ph; 2e, R=ⁱPr). The structure of the complexes 2 has been established by an X-ray diffraction study on the tri-isopropylphosphine-substituted cluster 2e. Benzaldehyde is obtained from complex 2a by bubbling hydrogen through a heated solution of the complex. A mechanism for the carbonylation of μ₃-benzyne is proposed and implications for metal surface chemistry discussed.

Full text of DOI:10.1016/S0022-328X(98)00448-3

Journal of Organometallic Chemistry 565 (1998) 141–151
Linking of benzyne and carbon monoxide at a triruthenium centre by
migratory insertion1
Jonathan P.H. Charmant, Helen A.A. Dickson, Nigel J. Grist, Selby A.R. Knox *,
A. Guy Orpen, Kathryn Saynor, Josep M. Vin˜as
School of Chemistry, Uni6ersity of Bristol, Bristol BS8 1TS, UK
Received 27 November 1997
Abstract
The v3-benzyne complex [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a) reacts at room temperature (r.t.) with carbon monoxide (1 atm),
trimethylphosphite, or t-butylisocyanide to give complexes [Ru3(CO)6L2(v-PPh2)2(v3-C6H4CO)] (2a, L=CO; 2b, L=P(OMe)3;
2c, L=tBuNC) containing an ortho-metallated v3-benzoyl ligand. Studies with 13CO confirm that the reaction involves a
migratory insertion of CO into a benzyne-CO |-bond. The v3-benzoyl products are formed exclusively when a large excess of the
y-acceptor ligand is used, but at lower concentrations substitution of CO by the incoming ligand also occurs to give the complexes
[Ru3(CO)6L(v-PPh2)2(v3-C6H4)] [1b, L=P(OMe)3; 1c, L=tBuNC]. Although 13C-labelling studies show that the reaction of 1a
with CO is irreversible at r.t., it is readily reversed by warming complex 2a in hexane. No reaction occurs at r.t. between complex
1a and triphenylphosphine or tri-isopropylphosphine, but on heating in toluene the phosphine-substituted complexes
[Ru3(CO)6(PR3)(v-PPh2)2(v3-C6H4)] (1d, R=Ph; 1e, R=iPr) are formed, which upon carbonylation give complexes
[Ru3(CO)7(PR3)(v-PPh2)2(v3-C6H4CO)] (2d, R=Ph; 2e, R=iPr). The structure of the complexes 2 has been established by an
X-ray diffraction study on the tri-isopropylphosphine-substituted cluster 2e. Benzaldehyde is obtained from complex 2a by
bubbling hydrogen through a heated solution of the complex. A mechanism for the carbonylation of v3-benzyne is proposed and
implications for metal surface chemistry discussed. © 1998 Elsevier Science S.A. All rights reserved.
Keywords: Benzyne complex; Tri-isopropylphosphine; X-ray diffraction
1. Introduction
of a triruthenium v3-benzyne complex [Ru3(CO)7(v-
PPh2)2(v3-C6H4)] (1a) with CO and other y-acceptor
ligands are described. These studies reveal that CO
undergoes migratory insertion into a benzyne-CO |-
bond, affording an ortho-metallated benzoyl ligand
which can be removed from the metal centre as ben-
zaldehyde through reaction with dihydrogen, providing
a model pathway for a metal surface process. There is
also relevance to homogeneous catalysis, in that forma-
tion of acyl groups by migratory insertion of carbon
monoxide into transition metal–alkyl bonds is a key
step in several commercially important processes, e.g.
hydroformylation and the Monsanto acetic acid synthe-
sis. The insertion of CO into other types of transition
metal–carbon bond has also attracted interest, includ-
Benzene is known to undergo dissociative chemisorp-
tion, i.e. C–H bond cleavage, on transition metal sur-
faces and likely surface species include phenyl and
benzyne [1]. The discovery [2] in this laboratory of a
range of polynuclear ruthenium complexes containing
benzyne bound to three, four and five metal atoms,
therefore provided an opportunity, based on the clus-
ter-surface analogy [3], to gain an insight into the
dissociative chemisorption of benzene through an ex-
ploration of their reactivity. In this paper the reactions
* Corresponding author.
1 Dedicated to Professor Michael Bruce on the occasion of his 60th
birthday.
0022-328X/98/$19.00 © 1998 Elsevier Science S.A. All rights reserved.
PII S0022-328X(98)00448-3

142
J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
Table 1
Analytical, physical and IR data for new complexes
Complex Colour
M. Wt.a,b
Analysis/%a,c
wCO /cm−1d
C
H
1b
1c
Red
Red
1043
1000
(1044)
(1003)
44.96
e
(44.69)
3.19
e
(3.35)
(3.32)
2020 m
1996 vs
2027 w
1941 w
2027 mw 2004 vs
1953 w
2026 m
1953 m
2018 mw 1997 vs
(49.20)
(54.96)
(50.14)
(46.76)
2159 wf
1960 m
2052 vw
1961 mw
2049 vw
1980 m
2085 s
1991 s
1d
1e
2a
Red
1180
1075
e
(1182)
(1080)
(1004)
55.28
49.88
47.02
3.41
4.49
2.93
(3.33)
(4.21)
(2.41)
1985 w
1972 mw
1995 ms
1928 vw
2016 mw 2005 vs
Red
1971 ms 1955 ms 1941 vw 1917 w
Yellow
2069 s
1989 m
2020s
2027 vs
2030 m
1967 vw 1953w
1946 w
1946w
2026 s
2020 m
2012 mw
1996 mw
2037 vs
2165 mf
2073 vs
1984 w
2073 s
1935 w
2000 m
2014 vs
2b
2c
2d
Yellow
Yellow
Yellow
1194
g
1238
(1196)
(1114)
(1238)
43.26
50.77
52.98
(43.35)
(52.09)
(52.60)
3.55
3.81
5.11
(3.75)
(4.55)
(5.50)
1968 m
1962 s
1950 mw
1913 w
1983 m
2023 ms 2003 w
2e
Yellow
e
(1136)
49.76
(49.78)
3.94
(4.00)
2058 vw 2023 vs
2001 w
1984w
a Calculated values in parentheses.
b FAB mass spectrometry.
c Samples crystallised from dichloromethane-hexane unless otherwise stated.
d Hexane solution.
e Satisfactory values not obtained.
f w(CN).
g Found [M-tBu]+, m/z=1056.
ing insertion into transition metal–alkyne |-bonds in
metal cluster complexes [4]. A preliminary account of
this work has appeared [5].
carbonyl, which presumably absorbs below 1500 cm−1
.
The 24 benzoyl and phenyl protons present in the
molecule are seen as a complicated series of signals in the
1H-NMR spectrum, the broad range of chemical shift
values (the signals range from d 7.7 to 6.0) being
attributable to aromatic ring current effects in a
molecule which contains a crowded arrangement of
phenyl and benzoyl rings. Such effects have been confi-
2. Results and discussion
2.1. Reaction of [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
with CO
1
rmed by a H–1H COSY-NMR experiment carried out
on [Ru3(CO)6{P(OMe)3}2(v-PPh2)2(v3-C6H4CO)] (2b)
(see below). The presence of two inequivalent v-phos-
phido ligands is clealry shown by the 31P-NMR spectrum
which comprises two doublets, at l 170.8 and 150.0. The
benzoyl carbonyl gives a signal at l 278.6 in the 13C-
NMR spectrum which, like most of the other metal
bound carbon nuclei, is split into a doublet of doublets
by the two inequivalent phosphorus nuclei. Two signals
appear at l 164.7 and 156.7 due to the carbon nuclei at
the substituted positions of the benzoyl ring. These
signals are shifted towards the olefinic region of the
spectrum, indicating that some localisation of electron
density occurs in the ring due to the interaction of these
carbon atoms with the metal atom and carbonyl group.
Four doublets with large coupling constants are ob-
served for the ipso-carbon nuclei of the phenyl rings in
the phosphido ligands. These data, in conjunction with
the other spectroscopic data for 2a (Tables 1–3), are
consistent with the structure shown in Scheme 1 in which
two molecules of CO have been incorporated into 1a to
yield a a novel ortho-metallated benzoyl complex.
Reaction of the v3-benzyne complex 1a with CO
occurs readily and cleanly under mild conditions, with
uptake of two molecules of CO. Thus, when CO is
bubbled through a dichloromethane solution at r.t., the
colour gradually changes from red to yellow over 3 days
and IR monitoring reveals a smooth transformation into
a single new species. Chromatography then gives yellow
[Ru3(CO)8(v-PPh2)2(v3-C6H4CO)] (2a) in near quantita-
tive yield. The reaction is more rapid in toluene under
3 atm of CO, when after 18h a yield of 75% is obtained.
Crystals of 2a proved unsuitable for X-ray diffraction
but the structure of the new complex was firmly estab-
lished by a crystallographic study on a phosphine deriva-
tive, as described later. Analytical, IR and mass
spectroscopic data for this and other new complexes are
given in Table 1 1H- and 31P-NMR data in Table 2, and
13C-NMR data in Table 3.
The IR spectrum of 2a shows eight terminal carbonyl
stretching bands, reflecting the asymmetry of the com-
plex, but no band could be detected for the benzoyl

J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
143
Table 2
1H- and 31P-NMR data for new complexes
Complex
1H-NMR (l)a,b
31P{1H}-NMR (l)a,b
1b
7.79–6.44 (m, 24H, 4Ph and C6H4), 3.49 (d, J 12, 9H,
277.4 (d, J 175, PPh2), 196.0 (dd, J 175, 25, PPh2), 151.2 (d, J
P[OCH3]3)
25, P[OCH3]3)
1c
1d
1e
7.83–6.22 (m, 24H, 4Ph and C6H4), 1.00 (s, 9H, t-C4H9NC)
268.1 (d, J 175, PPh2), 201.9 (d, J 175, PPh2)
7.70–6.31 (m, 39H, 7Ph and C6H4)
273.1 (d, J 170, PPh2), 189.0 (d, J 170, PPh2), 42.5 (s, PPh3)
267.1 (d, J 166, PPh2), 175.0 (d, J 166, PPh2), 55.6 (s, PPri3)
7.76–6.46 (m, 24H, 4Ph and C6H4), 2.46 (br, 3H,
P[CH(CH3)2]3), 1.27 (br, 9H, P[CH(CH3)2]3)d, 1.07 (br, 9H,
P[CH(CH3)2]3)d
2a
2b
7.74–5.99 (m, 24H, 4Ph and C6H4)
170.8 (d, J 27, PPh2), 150.0 (d, J 27, PPh2)c
7.81–6.27 (m, 24H, 4Ph and C6H4), 3.80 (d, J 12, 9H,
P[OCH3]3), 3.45 (d. J 11, 9H, P[OCH3]3)
159.8 (ddd, J 269, 66, 27, PPh2), 147.6 (ddd, J 66, 27, 2,
P[OCH3]3), 141.1 (dd, J 269, 2, P[OCH3]3), 136.2 (dd, J 27, 2,
PPh2)
2c
2d
2e
7.76–6.10 (m, 24H, 4Ph and C6H4), 1.51 (s, 9H, t-C4H9NC),
1.29 (s, 9H, t-C4H9NC)
159.9 (d, J 31, PPh2), 143.9 (d, J 31, PPh2)
7.76–6.01 (m, 39H, 7Ph and C6H4)c
169.4 (dd, J 40, 31, PPh2), 132.2 (d, J 31, PPh2), 41.5 (d, J 40,
PPh3)c
8.04–6.32 (m, 24H, 4Ph and C6H4), 2.51 (d, JHH 7, 3H,
168.7 (dd, J 39, 29, PPh2), 125.1 (d, J 29, PPh2), 55.6 (d, J
P[CH(CH3)2]3)e, 2.47 (d, JHH 7, 3H, P[CH(CH3)2]3)e, 1.34 (dd, 39, PPr3i )
JPH 15, JHH 7, 9H, P[CH(CH3)2]3)d, 0.93 (dd, JPH 14, JHH 7,
9H, P[CH(CH3)2]3)d
a CD2Cl2 solution unless otherwise stated.
b Coupling constant, J, in Hz.
c CDCl3 solution.
d Diastereotopic methyls.
e Diastereotopic hydrogens.
terminal carbonyl sites indicates that carbonyl scram-
bling must occur at some stage after the initial CO
uptake has taken place.
The key question regarding the formation of 2a is:
does the benzoyl carbonyl arise from incoming CO or
from a coordinated CO of 1a? Intuitively the latter
would be expected, i.e. that this is a migratory insertion
reaction in which benzyne first migrates to coordinated
CO, creating an unsaturated ruthenium centre to which
external CO then coordinates. Labelling studies em-
ploying 13C-enriched CO have shown that this is indeed
the case. Thus, treatment of 1a with 13CO at room
temperature gave complex 2a with a 13C-NMR spec-
trum which showed the label clearly confined to the
terminal carbonyl sites, i.e. no enhancement of the
benzoyl CO signal.
There is a variety of possible routes by which 1a can
be converted to 2a through migratory insertion of CO
and one plausible pathway is shown in Scheme 2. This
envisages initial migration of benzyne to a coordinated
CO to give 5, containing a ligand of a type which is well
established for alkyne-CO linking at a diruthenium
centre [6]. This creates a 16-electron ruthenium centre,
which accepts incoming CO to give 6. Subsequent
rearrangement of 6, involving coordination of acyl oxy-
gen and Ru–Ru bond cleavage, then produces the
v3-benzoyl ligand in 7, generating another 16-electron
centre to which a second CO molecule can coordinate,
giving 2a. The appearance of labelled CO at all of the
The labelling study reveals that carbonylation is ei-
ther irreversible or only very slowly reversible at r.t.,
since otherwise the label would enter the benzoyl CO
group, but it is possible to regenerate 1a quantitatively
by warming complex 2a in hexane or subjecting a
toluene solution of 2a to UV irradiation. This decar-
bonylation bears a striking resemblance to a previously
reported reaction in which a benzyne complex [Os3(v-
H)2(CO)9(v3-C6H4)](9) is formed by heating the v-ben-
zoyl complex [Os3(v-H)(CO)10(v-PhCO)] (8) [7]. In the
light of our observations it is likely that the mechanism
of this reaction involves CO loss followed by ortho-
metallation to generate a complex containing a ligand
similar to that in complex 2a, which then undergoes
decarbonylation to give benzyne.

144
J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
Table 3
13C-NMR data for new complexes
Complex 13C-NMR (l)a,b
1b
1c
c
209.3 (d, J 9, CO), 203.6 (d, J 6, 2CO), 202.6 (t, J 9, CO), 199.5 (t, J 8, CO), 195.7 (s, CO), 162.4 (s, C4H9NC), 158.0 (d, J 16,
Ru-bound C6H4), 153.3 (d, J 7, Ru-bound C6H4), 144.6 (d, J 21, ipso-C6H5), 143.0 (d, J 30, ipso-C6H5), 142.0-141.5 (m,
2ipso-C6H5), 134.3 (d, J 9), 132.6 (dd, J 16, 10), 131.9 (d, J 13), 130.5 (s), 130.0 (s), 129.3 (s), 128.3 (d, J 9), 128.0 (t, J 10),
127.4 (d, J 10) (Ph and C6H4), 29.8 (s, C4H9NC)
1d
1e
2a
208.4 (m, CO), 204.1 (m, CO), 200.4 (m, CO), 198.2 (m, CO), 197.5 (m, 2CO), 153.0 (br, Ru-bound C6H4), 157.2 (br, Ru-bound
C6H4), 144.5 (d, J 24, ipso-C6H5), 144.1 (d, J 29, ipso-C6H5), 141.8 (d, J 24, ipso-C6H5), 141.1 (d, J 24, ipso-C6H5), 135.9 (d, J
42), 134.1 (d, J 11), 133.8 (d, J 9), 133.5 (d, J 9), 132.8 (d, J 9), 131.9 (d, J 11), 130.6 (s), 129.9 (s), 128.8 (s), 128.4 (s), 128.1 (t,
J 11), 127.5 (t, J 8) (Ph and C6H4)
209.3 (d, J 9, CO), 207.4 (t, J 10, CO), 206.8 (m, CO), 203.9 (dd, J 12, 5, CO), 201.9 (m, CO), 199.4-197.4 (m, CO), 158.3 (br,
Ru-bound C6H4), 154.1 (br, Ru-bound C6H4), 144.6-144.2 (m, 3ipso-C6H5), 141.3 (d, J 26, ipso-C6H5), 134.5 (d, J 9), 133.9 (d, J
9), 132.9 (d, J 10), 132.1 (d, J 13), 130.6 (s), 130.0 (s), 129.0 (s), 128.0 (d, J 10), 127.5 (dd, J 31, 9), 32.0 (d, J 23,
P[CH(CH3)2]3)d, 29.8 (d, J 23, P[CH(CH3)2]3)d, 20.2 (d, J 52, P[CH(CH3)2]3)
278.6 (dd, J 7, 4, C6H4CO), 198.9 (s, CO), 198.7 (d, J 11, CO), 198.2 (m, 2CO), 197.7 (s, CO), 197.1 (s, CO), 194.3 (d, J 9,
CO), 193.3 (d, J 13, CO), 164.7 (d, J 12, substituted C6H4CO), 156.7 (d, J 13, substituted C6H4CO), 144.5 (d, J 32, ipso-C6H5),
139.6 (d, J 37, ipso-C6H5), 137.8 (d, J 26, ipso-C6H5), 136.3 (d, J 36, ipso-C6H5), 134.3 (d, J 11), 133.4 (d, J 10), 133.1 (d, J 11),
131.5 (s), 132.0 (s), 130.0 (s), 129.6 (s), 128.8 (d, J 11), 128.5 (d, J 10), 127.3 (s), 126.6 (d, J 10), 122.7 (s), 121.7 (s) (Ph and
C6H4CO)
2b
2c
2d
2e
282.0 (dd, J 4, 4, C6H4CO), 221.4 (ddd, J 21, 13, 8, CO), 204.3 (d, J 9, CO), 203.3-202.9 (m, 2CO), 202.6 (dd, J 14, 8, CO),
198.0 (dd, J 13, 8, CO), 169.2 (dd, J 19, 13, substituted C6H4CO), 158.8 (d, J 16, substituted C6H4CO), 146.6 (d, J 27,
ipso-C6H5), 144.9 (d, J 3, ipso-C6H5), 140.8 (d, J 32, ipso-C6H5), 139.5 (d, J 7, ipso-C6H5), 139.1 (s), 134.7 (d, J 10), 134.0-133.5
(m), 129.3 (d, J 15), 128.5 (d, J 16), 128.0 (d, J 9), 127.7 (d, J 10), 126.4 (s), 126.3 (s), 121.4 (s), 120.4 (s) (Ph and C6H4CO),
52.7 (d, J 4, P[OCH3]3), 52.3 (d, J 6, P[OCH3]3)
280.1 (m, C6H4CO), 220.5 (dd, J 20, 10, CO), 203.2 (d, J 10, 2CO), 201.0 (d, J 9, CO), 197.9 (d, J 8, CO), 196.2 (d, J 14, CO),
172.7 (d, J 12, substituted C6H4CO), 156.1 (d, J 12, substituted C6H4CO), 146.6 (d, J 26, ipso-C6H5), 144.1 (s),e 143.8 (s),e 141.4
(d, J 35, ipso-C6H5), 140.0 (d, J 21, ipso-C6H5), 138.5 (d, J 33, ipso-C6H5), 134.2 (d, J 10), 133.8 (d, J 9), 133.4 (dd, J 21, 10),
129.8 (s), 129.2 (s), 128.9 (s), 128.3 (d, J 9), 128.1-127.9 (m), 126.3 (s), 126.1 (d, J 9), 121.1 (s), 120.5 (s) (Ph and C6H4CO), 30.4
(s, C4H9NC), 30.3 (s, C4H9NC)
279.8 (m, C6H4CO), 219.3 (d, J 15, CO), 205.4 (t, J 11, CO), 203.7 (d, J 7, CO), 203.0 (d, J 7, CO), 201.8 (d, J 7, CO), 200.7
(s, CO), 200.1 (s, CO), 199.1 (d, J 7, CO), 193.8 (d, J 9), 164.2 (d, J 12, substituted C6H4CO), 157.0 (d, J 12, substituted
C6H4CO), 145.5 (d, J 32, ipso-C6H5), 144.8 (m, ipso-C6H5), 140.8 (d, J 29, ipso-C6H5), 138.4 (d, J 30, ipso-C6H5), 134.5 (m),
134.1 (dd, J 21, 11), 133.8-133.5 (m), 130.9 (s), 130.2 (s), 129.0 (s), 128.5 (s), 128.1 (d, J 10), 128.0 (s), 127.9 (s), 127.5 (t, J 10),
126.8 (d, J 10), 122.2 (d, J 22) (Ph and C6H4CO)f
280.0 (m, C6H4CO), 220.0 (t, J 17, CO), 206.9 (t, J 11, CO), 205.7 (d, J 7, CO), 205.0 (d, J 7, CO), 202.0 (t, J 7, CO), 200.9 (s,
CO), 200.3 (s, CO), 199.3 (d, J 7, CO), 192.9 (d, J 10, CO), 164.2 (d, J 10, substituted C6H4CO), 157.1 (d, J 10, substituted
C6H4CO), 146.2-145.4 (m, 2ipso-C6H5), 142.4 (d, J 31, ipso-C6H5), 139.3 (d, J 22, ipso-C6H5), 134.6 (d, J 10), 134.2 (d, J 10),
134.0 (d, J 10), 133.8 (d, J 7), 133.3 (d, J 22), 131.2 (s), 129.2 (s), 128.6 (s), 128.3 (s), 128.2 (s), 127.5 (d, J 7), 127.2 (d, J 10),
126.7 (d, J 10), 122.7 (d, J 17) (Ph and C6H4CO), 28.4 (s, P[CH(CH3)2]3),d 28.3 (s, P[CH(CH3)2]3)d, 20.0 (s, P[CH(CH3)2]3)d,
17.9 (s, P[CH(CH3)2]3)d
a CD2Cl2 solution unless otherwise stated.
b Coupling constant J in Hz.
c Satisfactory data not obtained.
d Diastereotopic carbons.
e Due to impurity.
f CDCl3 solution.
This proved to be the case. Complex 1a reacts with a
10–20-fold excess of P(OMe)3 or tBuNC in
dichloromethane at r.t. within 2 h to give complexes
[Ru3(CO)6L2(v-PPh2)2(v3-C6H4CO)](2b, 2c) in 52 and
38% yields respectively. The use of only 2-fold excesses
of the ligands gave, in addition to 2b and 2c, the
mono-substituted complexes [Ru3(CO)6(L)(v-PPh2)2(v3-
C6H4)](1b,1c), isolated in 25 and 16% yields, respec-
tively. This suggests that, after migratory insertion and
2.2. Reactions of [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
with PR3 and BuNC
t
Since the initial step in the reaction of 1a with CO
has been shown to be a migration of benzyne to
coordinated CO followed by uptake of two molecules
of externally provided CO, the reaction of 1a with other
y-acceptor ligands L could be expected to yield prod-
ucts [Ru3(CO)6L2(v-PPh2)2(v3-C6H4CO)] similar to 2a.

J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
145
The complexes 1b–e have spectroscopic data similar
to those of the parent benzyne complex 1a (Tables
1–3). It is clear from integration of the 1H-NMR
spectra that each complex contains a single molecule of
t
PR3 or BuNC, confirmed by analytical data for all but
1c which does, however, show a molecular ion in its
mass spectrum. In view of the structure of 2e, deter-
mined by X-ray diffraction (see below), the most likely
site for the ligands L in the complexes 1b–e is that
shown in Scheme 1. However, the 31P-NMR spectra of
the PR3 complexes 1b, 1d and 1e differ in that while the
first shows a doublet for the P(OMe)3 phosphorus the
last two show singlets for the corresponding PPh3 and
PiPr3 nuclei. This suggests that the P(OMe)3 ligand is
arranged trans to one of the v-phosphido groups in 1b,
while in 1d and 1e the PPh3 and PiPr3 ligands lie cis.
The spectroscopic data for complexes 2b-e (Tables
1–3) are similar to those of 2a and consistent with the
structure depicted in Scheme 1. The presence of the
benzoyl ligand in each is revealed by the characteristic
carbonyl signal found at ca. l 280 in the 13C-NMR
spectra, while 13C- and 1H-NMR data confirm the
presence of two ligands L in 2b and 2c, and only one in
Scheme 1.
incorporation of one molecule of L, a decarbonylation
pathway exists by which the ortho-metallated benzoyl
ligand is reconverted to v3-benzyne.
The presence of two diphenylphosphido ligands in 1a
clearly causes crowding and, unlike P(OMe)3 and
tBuNC, the more bulky triphenylphosphine did not
react with the complex at r.t. within 3 days. However,
on heating 1a with PPh3 or PiPr3 in refluxing toluene
for 2 h the complexes 1d and 1e were formed in 95 and
48% yields, respectively. When 1d and 1e are subjected
to 2–3 atm of CO at r.t., the benzoyl complexes
[Ru3(CO)7(L)(v-PPh2)2(v3-C6H4CO)] (2d,2e) are formed
in ca. 50% yield within 5 days.
1
2d and 2e. A H–1H COSY experiment performed on
complex 2b has been used to fully characterise the
complicated phenyl and o-metallated benzoyl ligand
proton signals. The broad range of these signals range
(l 7.8–6.3 ppm) is attributed to ring current effects
between neighbouring phenyl/benzoyl rings. The 31P-
NMR spectrum of 2b is complicated, with coupling
observed between all four phosphorus nuclei. The phos-
phido phosphorus nuclei in all complexes of type 2
show mutual coupling constants of ca. 30 Hz and thus
the signals at l 159.8 and 136.2 in 2b are assigned to
these ligands, while the remaining signals at l 147.6 and
141.1 are assigned to the phosphite phosphorus nuclei.
The 31P{1H}-NMR spectra of 2d and 2e both contain
signals at ca. l 170 and 130, consistent with two
v-phosphido ligands; the lower field signal also shows
coupling to the phosphine phosphorus nucleus, which is
found at ca. l 50, and is thus attributed to the phos-
phido ligand which is bonded to the phosphine-substi-
tuted Ru atom.
Like 2a, the complexes 2b and 2c are formed as fine
yellow powders and also proved unsuitable for X-ray
studies. Without such data it is difficult to determine
how the two ligands L are distributed in the complexes,
but the structure depicted in Scheme 1, which has the
ligands bound to the ‘terminal’ ruthenium atoms of the
cluster, appears clearly the most suitable on steric
grounds; the central ruthenium, surrounded by the four
phenyls of the phosphido groups, will be very crowded.
If the pathway for ligand addition shown in Scheme 2
were followed it might have been expected that the two
t
incoming PR3 or BuNC ligands would be bound to a
Scheme 2.
single terminal ruthenium atom. However, the labelling

146
J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
Fig. 1. Molecular structure of 2e showing labelling scheme; all hydrogen atoms have been omitted for clarity.
study with 13CO clearly showed CO scrambling over all
the terminal carbonyl sites during the process and this
will allow addition of PR3 or BuNC to occur so as to
afford the thermodynamically most stable products.
Complex 2e did give suitable crystals and an X-ray
diffraction study was undertaken in order to establish the
nature of the ortho-substituted benzoyl ligand.
The most interesting aspect of the molecular structure
of 2e is the coordination of the metallated benzoyl ligand,
which bridges all three ruthenium atoms. Other pub-
lished structures containing the benzoyl ligand bonded to
metal clusters show coordination only of the acyl group
to the metal atoms, and no ortho-metalation [8–10]. No
clear pattern of bond length alternation is found in the
o-metallated benzoyl ligand ring, although there may be
some distortion, as indicated by the longest [C(13)–C(14)
t
2.3. Molecular structure of
[Ru3(CO)7(PPri3)(v-PPh2)2(v3-C6H4CO)] (2e)
1.441(12) A] and shortest [C(11)–C(12) 1.364(14) A]
C–C bond distances. The carbonyl group bridges two
ruthenium atoms in typical v-acyl fashion with a C(8)–
˚
˚
The molecular structure of 2e is shown in Fig. 1 and
˚
˚
important bond lengths and angles are given in Table 4.
O(8) distance of 1.280(10) A. This is about 0.06 A longer
than that found for typical aryl bound organic carbonyls
[11] due to interaction between Ru(3) and O(8) removing
electron density from the C(8)–O(8) bond. Evidence for
a carbene component in the bonding between Ru(2) and
the ligand is shown by a short Ru(2)–C(8) distance of
˚
The non-bonding Ru(1)–Ru(3) distance of 5.343(1) A
and Ru(1)–Ru(2)–Ru(3) bond angle of 143.1(1)° show
that coordination of the benzoyl ligand is accompanied
by opening of the Ru3 triangle present in the precursor
1e. The other Ru–Ru distances Ru(1)–Ru(2) and
˚
˚
˚
Ru(2)–Ru(3) of 2.849(1) and 2.783(1) A are typical of
2.033(8) A [cf. Ru(1)–C(14) 2.136(9) A] and a tight
Ru(3)–O(8)–C(8) bond angle of 103.5(5)° suggesting
that O(8) may be sp3 hybridised. Finally it is worth noting
that Ru(2) is somewhat unusual in that it has approxi-
mately pentagonal bipyramidal coordination with C(8)
and C(5) in the axial positions.
Ru–Ru single bonds. The complex has a total of 50
cluster valence electrons in accord with this open triangle
geometry. All of the carbonyl ligands in complex 2e are
terminal with the largest deviation from an ideal 180°
Ru–C–O angle shown by the Ru(2)–C(5)–O(5) angle of
171.4(8)°. Both phosphido ligands bridge Ru–Ru bonds
in symmetrical fashion. The bulky tri-isopropylphos-
phine ligand is bound to Ru(3) and is arranged effectively
cis to the adjacent phosphido ligand [P(2)–Ru(3)–P(3)
107.5°], consistent with the small coupling observed
between the phosphido and phosphine phosphorus nuclei
in the 31P-NMR spectrum.
2.4. Hydrogenation of
[Ru3(CO)8(v-PPh2)2(v3-C6H4CO)] (2a) and
[Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
In an attempt to remove the new ortho-substituted

J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
147
benzoyl ligand from complexation hydrogen was bub-
2.5. Conclusions
bled through a refluxing hexane solution of 2a for 3 h.
After this time the distinctive almond-like odour of
benzaldehyde was clearly apparent and gas-liquid chro-
matography confirmed its presence, and also that of
benzene, in a ratio of ca. 9:1. The IR spectrum of the
reaction mixture indicated the fate of the triruthenium
fragment, in showing the characteristic carbonyl bands
of the known complex [Ru3(v-H)2(CO)8(v-PPh2)2](10)
[12], which was isolated in 65% yield by column
chromatography.
The likelihood that the minor benzene product arose
from hydrogenation of complex 1a, formed by decar-
bonylation of 2a, was supported by heating a sample
of the former in toluene, when 10 was formed quanti-
tatively within 1 h, presumably with loss of benzene.
This work has described the reactions of the v3-ben-
zyne complex 1a with carbon monoxide and other
y-acceptor ligands. The linking of CO with benzyne in
the systems studied has been shown to be a low energy
process, occurring at r.t. under 1 atm of CO. The
process is readily reversed, with only gentle warming of
the benzoyl product being required to regenerate the
benzyne starting material. It has also been shown that
the benzoyl ligand in complex 2a may be removed by
hydrogenation as benzaldehyde. This completes a path-
way which may point to possible metal surface process
for the conversion of benzene to benzaldehyde, namely:
(i) adsorption of benzene, (ii) C–H activation to give
benzyne plus surface hydrogen, (iii) benzyne linking
with CO to yield a species analogous to that present in
complexes 2, and (iv) desorption of benzaldehyde fol-
lowing reaction with surface hydrogen. Step (i) has
been well studied [1], (ii) has been modelled for a 111
surface in the transformation of [Os3(CO)9(v3-C6H6)]
to [Os3H2(CO)9(v3-C6H4)] [13] and for a step site on
the same surface by the complex [Ru4(CO)11(v-
PPh)(v5-C6H4)] [14], (iii) is modelled by 2a, and (iv) by
the reaction of 2a with hydrogen.
Table 4
˚
Selected bond lengths (A) and angles (°) for complex 2e
Ru(1)ꢀRu(2)
Ru(1)ꢀC(1)
Ru(1)ꢀC(3)
Ru(1)ꢀP(1)
Ru(2)ꢀC(4)
Ru(2)ꢀC(8)
Ru(2)ꢀP(2)
Ru(3)ꢀC(7)
Ru(3)ꢀP(2)
C(1)ꢀO(1)
C(3)ꢀO(3)
C(5)ꢀO(5)
C(7)ꢀO(7)
C(8)ꢀO(8)
2.849(1)
1.877(9)
1.949(10)
2.342(2)
1.913(9)
2.033(8)
2.365(2)
1.843(10)
2.364(2)
1.142(11)
1.129(13)
1.131(12)
1.149(12)
1.280(10)
1.404(12)
1.364(14)
1.441(12)
Ru(1)· · ·Ru(3)
Ru(1)ꢀC(2)
Ru(1)ꢀC(14)
Ru(2)ꢀRu(3)
Ru(2)ꢀC(5)
Ru(2)ꢀP(1)
Ru(3)ꢀC(6)
Ru(3)ꢀO(8)
Ru(3)ꢀP(3)
C(2)ꢀO(2)
C(4)ꢀO(4)
C(6)ꢀO(6)
C(8)ꢀC(9)
C(9)ꢀC(10)
C(10)ꢀC(11)
C(12)ꢀC(13)
5.343(1)
1.962(10)
2.136(9)
2.783(1)
1.957(10)
2.367(2)
1.942(10)
2.170(6)
2.388(3)
1.122(13)
1.142(12)
1.119(12)
1.492(12)
1.387(13)
1.384(13)
1.385(14)
3. Experimental
All reactions were carried out using dried and de-
gassed solvents under a nitrogen atmosphere using
standard Schlenk techniques. Photolysis reactions were
carried out in silica glass tubes using a 500 W mercury
vapour lamp as a UV irradiation source. Unless other-
wise stated, separation of mixtures was carried out by
pre-adsorbing the crude products onto alumina prior
to chromatography on alumina columns (ca. 3×30
cm). IR spectra were recorded on a Perkin-Elmer 1710
Fourier Transform Spectrometer, using calcium
fluoride cells of 1 mm path length. Proton, 13C- and
31P-NMR spectra were obtained using Jeol FX-90,
GX-270 and GX-400 spectrometers. Elemental analy-
ses were performed by the Microanalytical Laboratory
of the School of Chemistry. Fast Atom Bombardment
mass spectra were carried out by the EPSRC Mass
Spectrometry Service Centre at the University of
Swansea. GLC measurements were performed using a
Perkin-Elmer 8600 GC instrument equipped with a
BPI column. Carbon monoxide (BOC), hydrogen
(BOC) and triphenylphosphine (Aldrich) were used as
supplied. t-Butyl isocyanide, triisopropylphosphine and
trimethylphosphite were distilled at reduced pressure
prior to use. Complex 1a was prepared by the method
previously reported [2].
C(9)ꢀC(14)
C(11)ꢀC(12)
C(13)ꢀC(14)
Ru(2)ꢀRu(1)ꢀC(14) 85.1(2)
C(14)ꢀRu(1)ꢀP(1) 91.7(2)
Ru(1)ꢀRu(2)ꢀC(8) 84.6(2)
Ru(2)ꢀRu(1)ꢀP(1) 53.2(1)
Ru(1)ꢀRu(2)ꢀRu(3) 143.1(1)
Ru(3)ꢀRu(2)ꢀC(8) 68.0(2)
Ru(3)ꢀRu(2)ꢀP(1)
Ru(1)ꢀRu(2)ꢀP(2) 150.8(1)
C(8)ꢀRu(2)ꢀP(2) 85.5(2)
Ru(1)ꢀRu(2)ꢀP(1)
C(8)ꢀRu(2)ꢀP(1)
Ru(3)ꢀRu(2)ꢀP(2)
P(1)ꢀRu(2)ꢀP(2)
Ru(2)ꢀRu(3)ꢀP(2)
Ru(2)ꢀRu(3)ꢀP(3)
P(2)ꢀRu(3)ꢀP(3)
Ru(1)ꢀC(2)ꢀO(2)
Ru(2)ꢀC(4)ꢀO(4)
Ru(3)ꢀC(6)ꢀO(6)
Ru(2)ꢀC(8)ꢀC(9)
C(9)ꢀC(8)ꢀO(8)
C(8)ꢀC(9)ꢀC(14)
C(9)ꢀC(10)ꢀC(11)
52.4(1)
96.9(2)
53.9(1)
101.9(1)
54.0(1)
156.7(1)
107.5(1)
175.3(9)
174.1(8)
178.6(7)
126.7(6)
115.5(7)
118.5(8)
12 0.8(8)
150.9(1)
Ru(2)ꢀRu(3)ꢀO(8) 69.4(2)
O(8)ꢀRu(3)ꢀP(2)
O(8)ꢀRu(3)ꢀP(3)
Ru(1)ꢀC(1)ꢀO(1)
Ru(1)ꢀC(3)ꢀO(3)
Ru(2)ꢀC(5)ꢀO(5)
Ru(3)ꢀC(7)ꢀO(7)
Ru(2)ꢀC(8)ꢀO(8)
C(8)ꢀC(9)ꢀC(10)
C(10)ꢀC(9)ꢀC(14)
C(10)ꢀC(11)ꢀC(12)
82.1(2)
96.2(2)
177.3(8)
176.4(9)
171.4(8)
174.9(8)
117.7(6)
118.9(8)
122.6(8)
C(11)ꢀC(12)ꢀC(13) 122.0(9)
Ru(1)ꢀC(14)ꢀC(9) 123.9(6)
C(12)ꢀC(13)ꢀC(14) 121.1(8)
Ru(1)ꢀC(14)ꢀC(13) 121.3(6)
Ru(3)ꢀO(8)ꢀC(8)
C(9)ꢀC(14)ꢀC(13)
Ru(1)ꢀP(1)ꢀRu(2)
114.8(8)
74.5(1)
103.5(5)
Ru(2)ꢀP(2)ꢀRu(3) 72.1(1)

148
J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
3.1. Carbonylation of [Ru3(CO)7(v-PPh2)2(v3-C6H4)]
(1a)
cm3, 0.317 mmol) and 1a (150 mg, 0.159 mmol) in
dichloromethane (50 cm3) were stirred at r.t. for 24 h,
then the solvent was removed under reduced pressure
and the residue was chromatographed. Elution with
hexane:dichloromethane (9:1) developed two yellow
bands containing trace amounts of products that were
not characterised. Further elution with hex-
ane:dichloromethane (7:3) produced a red band con-
taining 41 mg (25%) of [Ru3(CO)6{P(OMe)3}
(v-PPh2)2(v3-C6H4)](1b). Subsequent elution with hex-
ane:dichloromethane (3:2) developed a yellow band
from which 128 mg (67%) of [Ru3(CO)6{P(OMe)3}2(v-
PPh2)2(v3-C6H4CO)] (2b) was obtained.
(a) Carbon monoxide was bubbled through a solu-
tion of 1a (100 mg, 0.106 mmol) in dichloromethane
(150 cm3) for 3 days, during which time the solution
changed colour from dark red to yellow. The solvent
was removed under reduced pressure to give 2a in
quantitative yield.
(b) A solution of complex 1a (200 mg, 0.211 mmol)
in toluene (50 cm3) was subjected to carbon monoxide
(3 atm) for 18 h in a Fischer-Porter vessel. The reac-
tion mixture changed colour from dark red to yellow.
The solvent was removed under reduced pressure and
the residue was chromatographed on Florisil. Elution
with hexane:dichloromethane (6:1) developed two
bands. The first contained a trace of [Ru4(CO)11(v4-
PPh)(v4-C6H4)] [2] and the second gave 159 mg (75%)
of [Ru3(CO)8(v-PPh2)2(v3-C6H4CO)] (2a) as a yellow
powder after evaporaton of solvent.
(b) To a dichloromethane (50 cm3) solution of 1a
(100 mg, 0.105 mmol) 20 equiv. of trimethylphosphite
(1.0 cm3, 7.9 mmol) was added. After 2 h the solution
had changed colour from red to yellow. The solvent
was removed under reduced pressure and the residue
was pre-adsorbed onto alumina and chro-
matographed. Elution with hexane:dichloromethane
(3:2) developed a single yellow band containing 64 mg
(52%) of complex 2b.
3.2. Reaction of [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
with 13C-enriched carbon monoxide
3.5. Reaction of [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
with t-butyl isocyanide
A diethyl ether (75 cm3) solution of 1a (150 mg,
0.159 mmol) was frozen by cooling to −196°C. The
reaction vessel was placed under vacuum and then
isolated from the vacuum pump before 13C-enriched
carbon monoxide (ca. 80 cm3, 3.6 mmol) was intro-
duced into the tube at atmospheric pressure. After
4 days stirring at r.t. the solution had changed colour
from dark red to yellow. The solvent was removed
under reduced pressure and the residue was chro-
(a) To a dichloromethane (50 cm3) solution of 1a
(150 mg, 0.159 mmol) was added two equivalents of
t-butyl isocyanide (0.036 cm3, 0.317 mmol). After 24
h stirring at r.t. the solvent was removed under re-
duced pressure and the residue was chromatographed.
Elution with hexane:dichloromethane (9:1) developed
two yellow bands, which contained trace amounts of
products that were not characterised, and a red band
containing 26 mg (16%) of [Ru3(CO)6(tBuNC)(v-
PPh2)2(v3-C6H4)] (1c). Subsequent elution with hex-
matographed.
Elution
with
hexane:dichloro-
methane (4:1) developed a single band containing
the labelled product [Ru3(*CO)8(v-PPh2)2(v3-C6H4
CO)] (2a*).
ane:dichloromethane (7:3) produced
a
red band
containing 37 mg of a mixture of products that could
not be separated. Further elution with hex-
ane:dichloromethane (3:2) produced a yellow band
containing 28 mg (16%) of [Ru3(CO)6(tBuNC)2(v-
PPh2)2(v3-C6H4CO)] (2c).
3.3. Decarbonylation of
[Ru3(CO)8(v-PPh2)2(v3-C6H4CO)] (2a)
(a) A solution of 2a (26 mg, 0.026 mmol) in hexane
(50 cm3) slowly turned from yellow to red while being
heated at reflux for 2 h. The solvent was removed
under reduced pressure to give 1a in quantitative
yield.
(b) Nitrogen was slowly bubbled through a toluene
(150 cm3) solution of complex 2a (50 mg, 0.053
mmol) while it was subjected to UV irradiation for
2.5 h. The solvent was removed under reduced pres-
sure to leave a residue of 1a in quantitative yield.
(b) To a dichloromethane (60 cm3) solution of 1a
(150 mg, 0.159 mmol) was added a 10-fold excess of
t-butyl isocyanide (0.40 cm3, 3.5 mmol). After 0.5 h
the solution had changed colour from red to yellow.
The solvent was removed under reduced pressure and
the residue crystallised by slow diffusion of a pentane
layer into a dichloromethane solution, which pro-
duced 60 mg (38%) of yellow microcrystalline 2c.
3.4. Reaction of [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
with trimethylphosphite
3.6. Reaction of [Ru3(CO)7(v-PPh2)2(v3-C6H4)] (1a)
with triphenylphosphine
(a) Two equivalents of trimethylphosphite (0.04
A solution of 1a (100 mg, 0.106 mmol) and

J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
149
triphenylphosphine (100 mg, 0.381 mmol) in toluene (80
cm3) was heated at reflux for 10 min. The solvent was
removed under reduced pressure and the residue was
chromatographed. Two bands were developed. The first,
eluted with hexane:dichloromethane (9:1), gave a trace
of unreacted complex 1a. The second, eluted with hex-
ane:dichloromethane (3:2) gave 118 mg (95%) of
[Ru3(CO)6(PPh3)(v-PPh2)2(v3-C6H4)] (1d).
(150 cm3) solution of 2a (27 mg, 0.027 mmol) for 3 h.
A sample of the reaction mixture was then analysed by
GLC, revealing the presence of benzaldehyde and ben-
zene in 9:1 ratio. After removal of solvet under reduced
pressure the residue was chromatographed on Florisil.
Elution with hexane:dichloromethane (9:1) developed
two bands. The first gave 15 mg (65%) of yellow
[Ru3(v-H)2(CO)8(v-PPh2)2](10) [12], identified by IR
and-NMR spectroscopy. The second contained a trace
of complex 1a.
3.7. Reaction of [Ru3(CO)7(v-PPh2)2(v3-p2-C6H4)] (1a)
with triisopropylphosphine
3.11. Hydrogenation of [Ru3(CO)7(v-PPh2)2(v3-C6H4)]
(1a)
A solution of 1a (278 mg, 0.294 mmol) and triiso-
propylphosphine (0.30 cm3, 0.52 mmol) in toluene (50
cm3) was heated at reflux for 1.5 h. The solvent was
removed under reduced pressure and the residue was
chromatographed. Elution with hexane:dichloro-
methane (19:1) developed three bands: first, unreacted
complex 1a (37 mg, 13%); second [Ru3(CO)6(PiPr3)(v-
PPh2)2(v3-C6H4)] (1e) (152 mg, 48%) and third, 50 mg of
a mixture of products that could not be separated.
Hydrogen was bubbled through a solution of 1a (50
mg, 0.053 mmol) in toluene (150 cm3) while heating at
reflux for 1 h. The solvent was removed under reduced
pressure to give yellow [Ru3(v-H)2(CO)8(v-PPh2)2] (10)
in quantitative yield.
3.12. Structure determination for
3.8. Carbonylation of
[Ru3(CO)7(PiPr3)(v-PPh2)2(v3-C6H4CO)] (2e)
[Ru3(CO)6(PPh3)(v-PPh2)2(v3-C6H4)] (1d)
Crystal data: C47H45O8P3Ru3, M=1134.0, or-
A solution of 1d (200 mg, 0.169 mmol) in toluene (50
cm3) was subjected to CO (3 atm) for 5 days in a
Fischer-Porter vessel. The reaction mixture changed
colour from dark red to yellow. The solvent was re-
moved under reduced pressure and the residue was
chromatographed on Florisil. Elution with hex-
ane:dichloromethane (4:1) developed two bands. The
first contained a trace of unreacted 1d and the second
gave 105 mg (50%) of [Ru3(CO)7(PPh3)(v-PPh2)2(v3-
C6H4CO)] (2d).
thorhombic, space group Pbca (no. 61), a=19.448(6),
3
˚
˚
b=19.568(6), c=24.135(8) A, U=9180(6) A , Z=8,
˚
D
calc=1.64 g cm−3, D=0.7107 A, v(Mo–Kh)=11.1
cm−1, F(000)=4432, T=293 K.
A single crystal of 2e (approximate dimensions 0.3×
0.2×0.1 mm) was mounted in a thin-walled glass capil-
lary and held in place with epoxy glue. All diffraction
measurements were made at r.t. (293 K) on a Siemens
four-circle R3m/V diffractometer, using graphite
monochromated Mo–Kh X-radiation. Unit cell dimen-
sions were determined from 29 centred reflections in the
range 15B2qB26°. A total of 9457 diffracted intensi-
ties, including check reflections, were measured in a
unique octant of reciprocal space for 4B2qB50° by
Wyckoff ꢀ scans. Three check reflections (−7 0 4, −1
−7 4, −3 −5 7) remeasured after every 50 ordinary
data showed no significant decay over the period of data
collection. Of all the intensity data collected, 8131
unique observations remained after averaging of dupli-
cate and equivalent measurements and deletion of sys-
tematic absences, of these 4700 with I\2|(I) were
retained for use in structure solution and refinement. An
absorption correction was applied on the basis of 432
azimuthal scan data, maximum and minimum transmis-
sion coefficients being 0.291 and 0.261, respectively.
Lorentz and polarisation corrections were applied.
The structure was solved by Patterson and Fourier
methods. All non-hydrogen atoms were assigned an-
isotropic displacement parameters and all hydrogen
atoms fixed isotropic displacement parameters. All non-
hydrogen atoms were refined without positional con-
3.9. Carbonylation of
[Ru3(CO)6(PiPr3)(v-PPh2)2(v3-p2-C6H4)] (1e)
A solution of 1e (260 mg, 0.241 mmol) in diethyl ether
(50 cm3) was subjected to carbon monoxide (2 atm) for
17 h in a Fischer-Porter vessel, during which time the
reaction mixture changed colour from dark red to
yellow. The solvent was removed under reduced pressure
and the residue was chromatographed. Elution with
hexane:dichloromethane (19:1) gave 10 mg (4%) of
complex
1a.
Further
elution
with
hexane:
dichloromethane (9:1) produced three bands. The first
gave 15 mg (6%) of 2a, the second 35 mg of unreacted
complex 1e, and the third 120 mg (44%) of
[Ru3(CO)7(PiPr3)(v-PPh2)2(v3-C6H4CO)] (2e).
3.10. Hydrogenation of
[Ru3(CO)8(v-PPh2)2(v3-C6H4CO)] (2a)
Hydrogen was bubbled through a refuxing hexane

150
J.P.H. Charmant et al. / Journal of Organometallic Chemistry 565 (1998) 141–151
Table 5
traints. All hydrogen atoms were constrained to ide-
alised geometries (C–H 0.96 A) with fixed isotropic
Atomic co-ordinates (×104) for complex 2e
˚
displacement parameters. Full-matrix least squares
refinement of this model (550 parameters) converged
to final residual indicies R=0.048, R%=0.043, S=
1.16, where R=ꢀꢁDꢁ/ꢀꢁFoꢁ; R’=(ꢀwD2/ꢀwFo2)0.5; S=
[ꢀwD2/(No−Nv)]0.5; D=Fo−Fc and No, Nv=number
of observations and of variables. Weights, w, were set
equal to [|2c(Fo)+gFo2]−1, where |c2(Fo) is the vari-
ance in Fo due to counting statistics and g=0.0004
was chosen to minimise the variation if S as a func-
tion of ꢁFoꢁ. Final electron-density difference maps
showed no features outside the range +0.3 to −0.3
Atom
x
y
z
Ru(1)
Ru(2)
Ru(3)
C(1)
C(2)
C(3)
C(4)
C(5)
C(6)
C(7)
4971(1)
4585(1)
3990(1)
4945(5)
5276(5)
5895(5)
5064(5)
5428(5)
4246(5)
4684(5)
3725(4)
3499(5)
2840(5)
2608(5)
3045(5)
3708(5)
3961(4)
5162(4)
5449(5)
5865(6)
6000(6)
5730(6)
5310(5)
3809(4)
3289(5)
2753(5)
2738(6)
3241(6)
3779(5)
3019(4)
2631(5)
1947(6)
1654(6)
2026(5)
2708(5)
4250(4)
4050(6)
4367(6)
4881(6)
5086(6)
4775(5)
2768(5)
3310(6)
2141(6)
2346(5)
2496(7)
1953(5)
3356(6)
3905(7)
2783(6)
4930(4)
5457(4)
6435(4)
5353(4)
5922(3)
4384(4)
5151(4)
3350(3)
4539(1)
3884(1)
3112(1)
2185(1)
2082(1)
1210(1)
2718(5)
1310(5)
2441(5)
1270(5)
2361(5)
305(5)
2663(1)
1527(1)
752(1)
3309(4)
2974(4)
2427(4)
1743(4)
1146(4)
1011(4)
233(4)
1827(4)
2418(3)
2538(4)
3079(4)
3494(4)
3388(3)
2829(3)
1967(4)
2404(4)
2315(6)
1778(6)
1334(5)
1427(4)
2319(4)
2663(4)
2822(4)
2657(5)
2326(5)
2150(5)
852(4)
1178(4)
1621(4)
1595(4)
1369(4)
1339(5)
1529(5)
1750(4)
1810(4)
3742(4)
4110(4)
4673(5)
4865(5)
4516(5)
3947(4)
3594(4)
3353(5)
3776(5)
4446(5)
4679(6)
4270(5)
2749(4)
2908(4)
3120(5)
3184(6)
3061(5)
2836(5)
3034(4)
3726(5)
4209(5)
4017(6)
3347(5)
2860(5)
1408(5)
1731(5)
1188(6)
505(5)
C(8)
C(9)
eA−3, the largest of these being close to the ruthe-
˚
C(10)
C(11)
C(12)
C(13)
C(14)
C(15)
C(16)
C(17)
C(18)
C(19)
C(20)
C(21)
C(22)
C(23)
C(24)
C(25)
C(26)
C(27)
C(28)
C(29)
C(30)
C(31)
C(32)
C(33)
C(34)
C(35)
C(36)
C(37)
C(38)
C(39)
C(40)
C(41)
C(42)
C(43)
C(44)
C(45)
C(46)
C(47)
O(1)
nium atoms. Table 5 lists the final atomic positional
parameters for the freely refined atoms, and Table 4
the selected bond lengths and inter-bond angles. All
calculations were carried out using programs of the
SHELXTL package [15]. Complex neutral-atom scat-
tering factors were taken from ref. [16].
Additional information available from the Cam-
bridge Crystallographic Data Centre comprises H-
atom co-ordinates, thermal parameters and remaining
bond lengths and angles.
Acknowledgements
We are grateful to the EPSRC for the award of
Research Studentships (to JPHC, HAAD, and NJG)
and for support, the EU through the framework of
the Community Science programme for support, and
CIRIT (Generalitat de Catalunya) for travel grants
(to JMV).
382(4)
425(5)
931(5)
1403(5)
1371(4)
287(3)
313(4)
−12(5)
−383(4)
−411(4)
−86(4)
−340(4)
−707(4)
−681(5)
538(4)
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−46(6)
1096(6)
−13(5)
98(7)
−437(6)
3065(4)
832(4)
963(4)
801(5)
−234(4)
−663(5)
−472(5)
3689(3)
3186(3)
2284(3)
1824(3)
907(3)
1152(3)
−59(3)
1485(2)
2101(1)
772(1)
O(2)
O(3)
O(4)
O(5)
O(6)
O(7)
O(8)
P(1)
2555(4)
773(3)
2438(4)
−222(4)
1156(4)
1288(3)
3062(1)
2413(1)
781(1)
P(2)
P(3)
154(1)

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