Oligomerisation of alkynes at a pentamethylcyclopentadienyl-ruthenium centre

Article abstract of DOI:10.1039/b001981j

Reactions between the neutral vinylidene RuCl(=C=CHPh)(PPh³)Cp* 2 and AgOCCO₂Me gave Ru{ti'-C(C=CPh)= CHC(O)OMe-O}(PPh₃)Cp* 3, while either LiGCPh or HC=CPh/NaOMe afforded the known Ru{n₃-PhCHCHC= CPh(CHCPh)}(PPh₃)Cp* 1. Similarly, RuCl{=OCH(CO₂Me)}(PPh₃)Cp* 4 reacted with HC=CPh/NaOMe to give Ru{n₃-CH(CO₂Me)CHC=CPh(OCCO₂Me)}(PPh ₃)Cp* 5. Complex 3 reacted with HGCCO₂R (R = Me or Et) to give the 1,3,4,5-tetraen-l-yls Ru{n′,n²-C(CO2R)=CHCPh=C=C=CH(CO2Me)}(PPh₃)CP* (R = Me 6 or Et 7)] and with HOCSiMe₃ to give a mixture of Ru{ii3-CH(CO₂Me)C(CH=CHSiMe₃)C=CPhCHCSiMe ₃}(PPh₃)Cp* 8 and Ru{nJ-CH(CO₂Me)CHC=CPh(C=CSiMe₃)}(PPh ₃)Cp* 9. Crystal structures of 1,3 and 5-8 were determined. These reactions provide routes to the stepwise formation of novel non-cyclic oligomers of 1-alkynes, with 8 containing the first example derived from four alkynes. The Royal Society of Chemistry 2000.

Full text of DOI:10.1039/b001981j

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Oligomerisation of alkynes at a pentamethylcyclopentadienyl-
ruthenium centre†
Michael I. Bruce,*a Ben C. Hall,a Brian W. Skelton,b Allan H. Whiteb and
Natasha N. Zaitsevaa
a Department of Chemistry, University of Adelaide, Adelaide, South Australia 5005, Australia.
E-mail: michael.bruce@adelaide.edu.au
b Department of Chemistry, University of Western Australia, Nedlands,
Western Australia 6907, Australia
Received 13th March 2000, Accepted 4th May 2000
Published on the Web 21st June 2000
1
᎐
᎐
᎐
Reactions between the neutral vinylidene RuCl(᎐C᎐CHPh)(PPh )Cp* 2 and AgC᎐CCO Me gave Ru{η -C(C᎐CPh)᎐
᎐ ᎐
᎐
᎐
᎐
3
2
3
᎐
CHC(O)OMe-O}(PPh )Cp* 3, while either LiC᎐CPh or HC᎐CPh/NaOMe afforded the known Ru{η -PhCHCHC᎐
CPh(C᎐CPh)}(PPh )Cp* 1. Similarly, RuCl{᎐C᎐CH(CO Me)}(PPh )Cp* 4 reacted with HC᎐CPh/NaOMe to give
᎐ ᎐
᎐
᎐
᎐
3
᎐
᎐
᎐
᎐
3
2
3
3
᎐
᎐
Ru{η -CH(CO Me)CHC᎐CPh(C᎐CCO Me)}(PPh )Cp* 5. Complex 3 reacted with HC᎐CCO R (R = Me or Et) to
᎐
᎐
᎐
2
2
3
2
give the 1,3,4,5-tetraen-1-yls Ru{η1,η2-C(CO R)᎐CHCPh᎐C᎐C᎐CH(CO Me)}(PPh )Cp* (R = Me 6 or Et 7)] and
᎐
᎐ ᎐ ᎐
2
2
3
3
᎐
᎐
᎐
with HC᎐CSiMe to give a mixture of Ru{η -CH(CO Me)C(CH᎐CHSiMe )C᎐CPhC᎐CSiMe }(PPh )Cp* 8 and
Ru{η -CH(CO Me)CHC᎐CPh(C᎐CSiMe )}(PPh )Cp* 9. Crystal structures of 1, 3 and 5–8 were determined. These
᎐
᎐
᎐
3
2
3
3
3
3
᎐
᎐
᎐
2
3
3
reactions provide routes to the stepwise formation of novel non-cyclic oligomers of 1-alkynes, with 8 containing the
first example derived from four alkynes.
᎐
of HC᎐CPh in the presence of NaOMe. Further examination
Introduction
᎐
of this general reaction and the use of alkynyl anions as
reagents has resulted in the formation of complexes containing
organic ligands derived from two, three or four molecules of
alkyne, formed in stepwise reactions and therefore able to be
used in the formation of derivatives containing several different
alkynes. The organic ligands are linear or branched oligomers
and these reactions represent a novel method of coupling
alkynes at a ruthenium centre.
These studies provide further examples of combination of
alkynes at a Group 8 metal centre to give non-cyclic products.
While there have been many studies of the coupling of alkynyl
and vinylidene ligands to give butenynyl complexes or, more
rarely, the isomeric butatrienyl derivatives,8,9 incorporation of
more than two alkynes in the products has received much less
attention. Some years ago ruthenium complexes containing
both alkynyl and η3-enynyl ligands were found to undergo
coupling to give alkynylbutadienyl ligands in reactions which
are related to those described below.10 More recently, tri-11 and
tetramerisation12 of alkynes on rhodium complexes have been
reported.
We have recently described the preparation of some neutral
vinylideneruthenium complexes containing the RuCl(PPh3)Cp*
moiety from RuCl(PPh3)2Cp* and the alkyne in non-polar
solvents.1 In contrast to the reactions between RuCl(PPh3)2Cp
and 1-alkynes, which are usually carried out in methanol, thus
allowing dissociation of chloride and formation of the cationic
vinylidene complexes,2 the present route depends on dissoci-
ation of one of the bulky PPh3 ligands in place of chloride and
gives access to compounds of the type RuCl(᎐C᎐CHR)(PPh )-
᎐ ᎐
3
Cp*. Subsequent reactions in the presence of base (NaOMe or
NHMe2) and another ligand, L (≠ PPh3), have afforded chiral
᎐
complexes Ru(C᎐CR)(L)(PPh )Cp* by formal 1,3 elimination
᎐
3
of HCl.3 These complexes were formed with a variety of
ligands, including CO, C2H4, O2 and S2. Addition of cationic
electrophiles to the alkynyl compounds gives the corresponding
cationic vinylidene complexes.
The finding that RuH3(PR3)Cp* (R = Ph, Cy or Me) are
effective catalysts for the dimerisation of 1-alkynes to 1,3- and
cis- and trans-1,4-enynes has been interpreted in terms of coup-
ling of alkynyl and vinylidene ligands at the ruthenium centre,
the stereochemistry being determined by the orientation of the
vinylidene.4 It was noted also that 1,2,3-trienes were obtained
Results
t
᎐
from HC᎐CR (exclusively for R = CH Ph, 16% for R = Bu ) and
᎐
2
The reactions to be described below are summarised in Scheme
that trimers or higher oligomers were obtained with smaller
alkynes. Later, it was found that the 16-electron complex
᎐
2. Instead of the expected complex Ru(C᎐CPh)(η-HC Ph)-
᎐
2
(PPh3)Cp*, or possibly the analogous phenylvinylidene deriv-
᎐
᎐
Ru(C᎐CPh)(PPh )Cp* catalysed the dimerisation of HC᎐CR
᎐
᎐
3
ative, the reaction between RuCl(᎐C᎐CHPh)(PPh )Cp* 2 and
᎐ ᎐
3
(R = Ph or CO2Me); the novel allylic complex, Ru{η3-PhCH-
phenylethyne, carried out in the presence of NaOMe, afforded a
yellow solid. We have determined the structures of two crystal-
line forms, one of which was the 1.5-benzene solvate described
᎐
CHC᎐CPh(C᎐CPh)}(PPh )Cp* (1; Scheme 1), with a trimer of
᎐
᎐
3
the alkyne, was obtained as a metal-containing product.5,6 The
16-electron complex may be solvated or possess an agostic
Ru ؒ ؒ ؒ H interaction, as found spectroscopically for the product
independently by others,5 whose composition corresponded to
᎐
the incorporation of two additional HC᎐CPh molecules into 2,
᎐
obtained from RuCl(᎐C᎐CHBut)(PPh )Cp* and C Me .7
3
᎐ ᎐
3
2
2
᎐
namely Ru{η -PhCHCHC᎐CPh(C᎐CPh)}(PPh )Cp* 1. The
᎐
᎐
3
Independently, we have found that complex 1 is formed in the
second form is solvent-free and both structures are experi-
reaction between RuCl(᎐C᎐CHPh)(PPh )Cp* 2 and an excess
᎐ ᎐
3
mentally identical. The same complex could be isolated, in
᎐
lower yield, from a reaction between 2 and LiC᎐CPh.
᎐
In order to find out more about these unusual systems, we
† Dedicated to Professor Helmut Werner, a respected and admired
friend and colleague, on the occasion of his birthday.
᎐
next examined the reaction between complex 2 and AgC᎐
᎐
DOI: 10.1039/b001981j
J. Chem. Soc., Dalton Trans., 2000, 2279–2286
This journal is © The Royal Society of Chemistry 2000
2279

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Scheme 1
᎐
the presence of an equimolar amount of HC᎐CPh gave a mix-
᎐
ture of 1 and 3. The spectroscopic properties of 3 were consist-
ent with its solid-state structure, with bands in the IR spectrum
at 2163, 1724 and 1558 cmϪ1 being assigned to ν(C᎐C), ν(CO)
᎐
᎐
1
and ν(C᎐C) absorptions, respectively. In the H NMR spec-
᎐
trum, doublet resonances at δ 1.40 and 6.25, having relative
intensities 15/1, were assigned to the Cp* and ᎐CH protons,
᎐
respectively. The CO2Me protons gave rise to a singlet reson-
ance at δ 3.33 and the Ph multiplet was between δ 7.17 and 7.50.
The 13C NMR spectrum contained signals for Cp* (δ 10.82 and
86.99) and CO2Me groups (δ 52.80 and 181.26), as well as for
᎐
the two C᎐C (δ 99.05 and 100.57) and ᎐CH carbons (δ 122.97).
᎐
᎐
The ion [M Ϫ H]ϩ was present in the electrospray (ES) mass
spectrum.
A different complex incorporating two additional alkyne
᎐
molecules was formed from 1 and HC᎐CCO Me in the presence
᎐
2
of NaOMe. This was identified as Ru{η3-CH(CO Me)CHC᎐
᎐
2
᎐
CPh(C᎐CCO Me)}(PPh )Cp* 5 by means of a single-crystal
᎐
2
3
X-ray structural study, and was accompanied by a small
amount of 3. The IR spectrum of 5 contained bands assigned
᎐
to ν(C᎐C) at 2186, ν(CO) at 1706 and ν(C᎐C) at 1616 and 1594
᎐
᎐
cmϪ1, while two singlets in the 1H NMR spectrum at δ 3.70 and
3.94 indicated the presence of two non-equivalent CO2Me
groups. Other resonances included a doublet at δ 1.47 (Cp*)
and two double doublets at δ 2.27 and 3.59 for the two CH
protons. In the 13C NMR spectrum the Cp* (δ 9.16 and 93.67),
CO2Me (δ 50.52, 52.32 and 217.0; the two ester CO resonances
᎐
are accidentally equivalent) and C᎐C carbons (δ 79.43 and
᎐
94.05) were accompanied by resonances at δ 112.11, 139.33,
155.55 and 174.73, assigned to the carbons of the C4 chain.
From solutions containing NaOMe, the highest ion in the ES
mass spectrum was [M ϩ Na]ϩ at m/z 791.
᎐
Complex 3 reacts with HC᎐CCO R (R = Me or Et) to give
᎐
2
the 1,3,4,5-tetraenyl complexes Ru{η1,η2-C(CO R)᎐CHCPh᎐
᎐
᎐
2
C᎐C᎐CH(CO Me)}(PPh )Cp* (R = Me 6 or Et 7), each
᎐ ᎐
2
3
obtained as a single product. Both complexes were character-
ised by single-crystal structure determinations and their spec-
troscopic properties were consistent with these structures. The
Cp* proton doublets are at δ 1.56 (R = Me) and 1.52 (Et), while
the common CO2Me groups are found at δ 3.33 and 3.37,
respectively. This assignment is assisted by replacement of the
1
CO2Me signal at δ 3.29 in the H NMR spectrum of 6 by the
CH2 multiplet at δ 3.61 for 7.
Scheme 2
Finally, a complex containing an organic ligand derived
CCO2Me. A red-brown complex was isolated in 56% yield and
from four alkyne molecules is obtained when 3 is treated with
1
᎐
᎐
identified as Ru{η -C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* 3
HC᎐CSiMe . The only tractable product was yellow crystal-
᎐
᎐
᎐
3
3
3
᎐
by an X-ray structural determination. This material was also
line Ru{η -CH(CO Me)C(CH᎐CHSiMe )C᎐CPhC᎐CSiMe }-
᎐
᎐
᎐
2
3
3
formed from the reaction between RuCl{᎐C᎐CH(CO Me)}-
(PPh3)Cp* 8, characterised by an X-ray structural study. This
complex has spectroscopic properties consistent with its solid-
᎐ ᎐
2
(PPh3)Cp* 413 and AgC᎐CPh. Treatment of 4 with NaOMe in
᎐
᎐
2280
J. Chem. Soc., Dalton Trans., 2000, 2279–2286

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3
᎐
Fig. 1 Plot of molecule 1 of Ru{η -PhCHCHC᎐CPh(C᎐CPh)}-
᎐
᎐
(PPh3)Cp* 1, showing the atom numbering scheme.
3
᎐
Fig. 3 Plot of a molecule of Ru{η -CH(CO2Me)CHC᎐CPh(C᎐CCO2-
᎐
᎐
Me)}(PPh3)Cp* 5, showing the atom numbering scheme.
1
᎐
Fig. 2 Plot of a molecule of Ru{η -C(C᎐CPh)᎐CHC(O)OMe-O}-
᎐
᎐
(PPh3)Cp* 3, showing the atom numbering scheme.
᎐
state structure, with a single ν(C᎐C) band at 2115 and a ν(CO)
᎐
1
absorption at 1699 cmϪ1. In the H NMR spectrum, appro-
priate signals can be assigned to SiMe3 (δ Ϫ0.23, 0.46), Cp*
(1.47), CO2Me (3.59) and CH protons (5.46, 6.66 and one
beneath the Ph multiplet). The ES mass spectrum contains Mϩ
at m/z 880. The ES mass spectrum of a second product, which
could only be obtained as a yellow oil which was unstable in
solution, contained Mϩ at m/z 782 and singlet resonances at
δ Ϫ0.74, 1.66 and 3.53 which we assign to SiMe3, Cp* and
CO2Me protons, respectively. These data are consistent with
Fig. 4 Plot of a molecule of Ru{η3-CH(CO Me)C(CH᎐CHSiMe )-
2
᎐
3
᎐
C᎐CPhC᎐CSiMe3}(PPh3)Cp* 8, showing the atom numbering scheme.
᎐
᎐
with average values 2.234–2.290 Å [neglecting the values for 3,
which are commented upon below]. For example, in RuCl-
(PPh3)2Cp* the average Ru–P distance is 2.341(6) Å, while Ru–
C(Cp*) separations range between 2.224 and 2.274(2) Å.14 The
structure of complex 1 has been reported before for a different
phase and our determination shows no significant differences
from the earlier study.6
3
᎐
the formulation Ru{η -CH(CO Me)CHC᎐CPhC᎐CSiMe }-
᎐
᎐
2
3
(PPh3)Cp* 9 and its formation can be accounted for by reac-
tions analogous to those leading to complex 5 (see below).
1
᎐
(a) Ru{ꢀ -C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* 3. In this
᎐
᎐
3
complex two alkyne molecules have combined to form a five-
membered chelate RuC3O ring, C(2) forming a σ bond to the
metal [Ru–C(2) 2.032(8) Å], while the ester carbonyl oxygen
forms a donor bond [Ru–O(11) 2.156(5) Å]. Atoms C(3)–C(4)
are separated by a triple bond, while C(1)–C(2) is a double
bond. In this molecule both the Ru–P [2.281(3) Å] and average
Ru–C(Cp*) separations [2.192 Å] are shorter than those found
in the other five complexes, probably as a result of there being
not only less steric interaction with the ring substituents, but
also lack of back bonding into the organic ligand. The latter
would result in more back donation into the PPh3 and Cp*
ligands with tighter bonding thereof.
Molecular structures of complexes 1, 3, 5, 6, 7 and 8
Plots of single molecules of each of these complexes are given
in Figs. 1–5 and selected structural data are collected in Table 1.
All contain an Ru(PPh3)Cp* fragment supporting the various
organic ligands. The geometrical parameters for this moiety are
similar to those found in a variety of related structures which
have been reported previously, with Ru–P between 2.311(2) and
2.338(1) Å and Ru–C(Cp*) between 2.203(5) and 2.368(7) Å,
3
᎐
(b) Ru{ꢀ -CH(CO Me)CHC᎐CPh(C᎐CCO Me)}(PPh )Cp*
᎐
᎐
2
2
3
᎐
3
5
and Ru{ꢀ -CH(CO Me)C(CH᎐CHSiMe )C᎐CPhC᎐CSi-
᎐
᎐
᎐
2
3
Me3}(PPh3)Cp* 8. The structures of these two complexes are
J. Chem. Soc., Dalton Trans., 2000, 2279–2286 2281

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Table 1 Selected bond parameters (bond lengths in Å, angles in Њ) for complexes 1, 3 and 5–8
1a
3
8
5
6a
7a
Ru–P
Ru–C(Cp*)
2.311, 2.323(2)
2.220–2.256,
2.231–2.273(6)
2.236, 2.243
2.281(3)
2.178–2.224(9)
2.3322(9)
2.213–2.282(3)
2.329(2)
2.203–2.274(5)
2.335, 2.338(1)
2.217–2.360,
2.231–2.372(6)
2.282, 2.290
2.330, 2.337(2)
2.223–2.351,
2.208–2.368(7)
2.281, 2.280
(av.)
2.192
2.245
2.234
Ru–C(1)
Ru–C(2)
Ru–C(3)
Ru–C(6)
2.305, 2.294(6)
2.124, 2.135(6)
2.029, 2.037(6)
2.214(3)
2.154(2)
2.044(3)
2.243(5)
2.117(5)
2.025(4)
2.032(8)
2.104, 2.098(4)
2.066, 2.083(5)
2.082, 2.085(5)
1.337, 1.332(6)
1.452, 1.465(6)
1.342, 1.343(7)
1.348, 1.337(7)
1.453, 1.456(7)
1.472, 1.487(7)
1.348, 1.366(8)
1.487, 1.486(7)
1.193, 1.183(7)
1.337, 1.347(7)
1.197, 1.200(7)
1.355, 1.356(7)
2.086, 2.087(5)
2.072, 2.077(5)
2.089, 2.096(5)
1.344, 1.363(6)
1.429, 1.439(7)
1.339, 1.333(7)
1.353, 1.343(8)
1.443(8), 1.455(7)
1.461(9), 1.466(8)
1.338(9), 1.367(8)
1.483(8), 1.460(7)
1.187, 1.189(7)
1.338, 1.299(7)
1.203, 1.207(7)
1.351, 1.348(6)
C(1)–C(2)
C(1)–C(11)
C(2)–C(3)
C(3)–C(4)
C(4)–C(5)
C(4)–C(41)
C(5)–C(6)
C(6)–C(61)
C(6)–O(61)
C(6)–O(62)
C(11)–O(11)
C(11)–O(12)
1.434, 1.426(9)
1.448, 1.461(8)
1.408, 1.421(8)
1.339, 1.340(9)
1.431, 1.439(9)
1.503, 1.494(9)
1.193(9), 1.19(1)
1.448(9), 1.44(1)
1.35(1)
1.44(1)
1.41(1)
1.19(1)
1.425(5)
1.486(5)
1.419(4)
1.352(5)
1.445(4)
1.485(3)
1.202(5)
1.426(7)
1.470(8)
1.429(7)
1.349(6)
1.456(8)
1.473(7)
1.180(9)
1.441(9)
1.44(1)
1.23(1)
1.36(1)
1.196(4)
1.349(5)
1.203(8)
1.353(7)
P–Ru–C,O(1)
P–Ru–C(2)
P–Ru–C(3)
P–Ru–C(6)
83.7, 84.9(2)
106.7, 106.4(2)
93.8, 93.5(2)
87.7(2)
90.3(2)
83.89(8)
104.42(9)
88.56(9)
88.8, 89.2(2)
103.5, 103.7(1)
89.5, 89.6(1)
89.2, 90.0(1)
103.1, 104.8(2)
88.3, 89.6(2)
92.0(2)
C(2)–Ru–C(6)
C(3)–Ru–C(6)
C(11)–C(1)–C(2)
C(1)–C(2)–C(3)
C(2)–C(3)–C(4)
C(3)–C(4)–C(5)
C(3)–C(4)–C(41)
C(4)–C(5)–C(6)
C(5)–C(6)–C(61)
C(1)–C(11)–O(11)
C(1)–C(11)–O(12)
108.2, 108.6(2)
74.0, 74.4(2)
108.4, 108.1(2)
74.0, 74.1(2)
123.2, 121.6(5)
149.7, 151.6(5)
161.2, 161.3(5)
109.9, 110.8(5)
124.6, 124.8(5)
119.6, 121.2(5)
134.1, 134.2(6)
120.6, 120.9(6)
124.0, 123.3(6)
176.6, 174.6(7)
176.3, 177.7(7)
112.9(7)
118.8(7)
177.7(8)
119.7(5)
115.6(5)
131.2(5)
120.0(4)
122.5, 122.3(4)
151.9, 150.9(5)
158.5, 160.6(5)
109.8, 111.5(4)
126.8, 126.8(4)
115.7, 114.8(4)
115.7, 113.9(5)
127.5, 127.6(4)
110.3, 110.0(4)
115.6(3)
134.3(2)
121.8(2)
178.9(9)
175.2(3)
116.7, 115.2(5)
117.1, 115.3(5)
127.4, 128.0(5)
111.2, 110.0(5)
121.1(8)
117.0(8)
a Values cited for molecule 1, 2. For 3: Ru–O(11) 2.156(5), P–Ru–O(11) 87.7(2), O(11)–Ru–C(2) 77.0(3), Ru–O(11)–C(11) 112.2(6). For 5: C(61)–
O(61) 1.187(8), C(61)–O(62) 1.331(7). For 6: C(6)–C(61)–O(61) 126.1(4), 125.9(5), C(6)–C(61)–O(62) 112.5, 112.5(4). For 7: C(6)–C(61)–O(61) 125.8,
125.2(5), C(6)–C(61)–O(62) 111.9, 114.9(5). For 8: C(2)–C(21) 1.485(4), C(21)–C(22) 1.329(6), Si(2)–C(22) 1.849(3), Si(6)–C(6) 1.830(4); Si(2)–
C(22)–C(21) 125.9(3), C(3)–C(2)–C(21) 121.0(3), C(2)–C(21)–C(22) 126.8(3), Si(6)–C(6)–C(5) 173.8(3).
C(4) [1.349(6), 1.352(5) Å], i.e. the ligands are η3-butadienyls.
These data can be compared with those for 1, in which the
Ru–C and the C–C distances are consistent with the same
arrangement of multiple bonds. In both 5 and 8, atom C(1)
carries H and CO2Me substituents, while C(4) carries the
phenyl and alkynyl groups. In 8 the central C(2) of the allyl
also carries the trans-CH᎐CH(SiMe ) group [C(21)–C(22)
᎐
3
1.329(4) Å].
(c) Ru{ꢀ1,ꢀ2-C(CO R)᎐CHCPh᎐CC᎐CH(CO Me)}(PPh )-
᎐
᎐
᎐
2
2
3
Cp* (R ؍ Me 6 or Et 7). As expected, the molecular structures
of complexes 6 and 7 are closely related and only 6 is depicted;
the structural determination of 7 enables us to comment on the
site of addition of the third alkyne molecule. The organic lig-
ands in each of these complexes is a linear oligomer derived
from three alkyne molecules and is attached to the ruthenium
by a π bond to C(2)–C(3) [2.104(4), 2.066(5); 2.086(5), 2.072(5)
Å; values for molecule 1 of each complex given] and a σ bond
to C(6) [2.082(5); 2.089(5) Å]. Atoms C(1–4) form a cumulene,
of which only the central C=C double bond is co-ordinated to
ruthenium, while there is also a double bond between atoms
C(5,6). The ligand is thus a 3-vinylbuta-1,2,3-triene, which is an
isomer of the diene found in 5. The substituents on atoms
C(3,5,7) have normal geometries. There are close parallels
between these structures and that of the complex Ru{η1,η2-
Fig.
5
Plot of a
molecule of Ru{η1,η2-C(CO2Me)᎐CHCPh᎐
᎐ ᎐
CC᎐CH(CO2Me)}(PPh3)Cp* 6, showing the atom numbering scheme.
᎐
closely related to that of 1, differing only in the substituents
which, however, exert some influence on the geometrical
parameters. Thus, an asymmetric allylic interaction of the
ruthenium with atoms C(1,2,3) [Ru–C(1) 2.243(5), 2.214(3),
Ru–C(2) 2.117(5), 2.154(2), Ru–C(3) 2.025(4), 2.044(3) Å]
results from the presence of a double bond between C(3)–
C(CF )᎐CHC(CF )᎐CC᎐CH(CF )}(PPh )Cp, another alkyne
᎐
᎐
᎐
3
3
3
3
᎐
trimerisation product obtained from HC᎐CCF and RuH-
᎐
3
(PPh3)2Cp,15 where, for example, the Ru–C distances are 2.11(1)
(σ-bonded) and 2.05, 2.09(1) Å (π-bonded).
2282
J. Chem. Soc., Dalton Trans., 2000, 2279–2286

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Discussion
Determination of the molecular structures of these complexes
allows some comment on the likely mechanisms of their
formation. In the earlier report on 1 it was suggested that
᎐
trimerisation of the alkyne (HC᎐CPh) occurred by initial co-
᎐
ordination of phenylethyne to the alkynylruthenium centre as
the phenylvinylidene, followed by dimerisation to intermediate
᎐
A. Displacement of dimer by HC᎐CPh with regeneration of
᎐
the alkynylruthenium centre is followed by co-ordination of the
dimer and intramolecular C–C bond formation occurs (formally
insertion of the third alkyne into an Ru–C bond of the dimer;
Scheme 1). Subsequent rearrangement involves co-ordination
of the terminal olefinic bond to give 1. This reaction course is
encouraged by the steric bulk of the Cp* and PPh3 ligands,
which offer some stability to the postulated 16-e intermediates.
The first reaction we describe affords a product 3 which con-
tains a ligand formed by formal combination of the phenyl-
ethynyl group with the ester vinylidene in precursor complex 4.
Scheme 3
The same complex is formed in the reverse reaction, namely
᎐
᎐
between 2 and AgC᎐CCO Me. These results can be explained if
formation of 1 from 2 and HC᎐CPh can also be described by an
᎐
᎐
2
replacement of the chloride in 2 is followed by a proton shift
from the phenylvinylidene to the methoxycarbonylethynyl
analogous sequence of reactions, which has the advantage of
not requiring the formation of the alkyne dimer.
group, followed by insertion of the resulting C᎐CH(CO Me)
In an attempt to determine whether complex 3 is an inter-
mediate en route to 5 we treated it with alkyl propiolates
(methyl and ethyl). From these reactions we obtained com-
plexes 6 and 7, which were shown to contain cumulene ligands
formed by addition of the alkyl ester to the “dimeric” ligand
in 3. The site of addition, defined as that closest to the metal
centre by the presence of methyl or ethyl ester groups, respec-
tively, can be accounted for if 3 isomerises to the η2-alkyne
isomer by displacement of the ester carbonyl group. This may
require the presence of the alkyl propiolate, which can co-
᎐
2
ligand into the Ru–C(sp) bond. Further reaction is prevented
by chelation of the ester carbonyl group into the vacant co-
ordination site on the metal centre (Scheme 3). The form-
ation of 1 in the reaction of 4 with phenylethyne in the presence
of base suggests that the intermediate containing the C᎐CH-
᎐
(CO2Me) ligand is labile towards replacement by phenylvinyl-
idene, consistent with previously observed reactivities of
complexes containing these two ligands.
In the reaction between complex 2 and methyl propiolate in
the presence of base we find specific formation of 5, which has
a structure analogous to that of 1, but with the terminal Ph
groups replaced by CO2Me, suggesting that in this case, dimer-
isation of the alkyne does not occur before complexation to the
metal. We suggest that the first step in this reaction is replace-
ment of chloride by the methyl propiolato group. Isomerisation
of the phenylvinylidene to η2-phenylethyne and insertion into
the Ru–C(sp) bond gives co-ordinatively unsaturated inter-
mediate B. Addition of a second molecule of methyl propiolate
as its vinylidene isomer is followed by insertion into the Ru–
C(sp2) bond, H migration and co-ordination of the terminal
ordinate to the metal centre and couple to the Ph end of the co-
᎐
ordinated C᎐C triple bond (Scheme 5). We note that the organic
᎐
ligand in these complexes is isomeric to that in 5, which may be
explained by a proton shift analogous to that found in con-
ventional alkyne–allene rearrangements. Formulation of 6 and
7 as shown emphasises the metallacyclopentadiene structure, a
familiar product or intermediate in alkyne oligomerisation
reactions.
᎐
The reaction between 3 and HC᎐CSiMe gave an unprece-
᎐
3
dented type of complex containing a ligand derived from four
alkyne molecules. In this case we suggest that isomerisation of 3
and addition of the free alkyne affords an η2-alkyne intermedi-
C᎐C double bond, as suggested for 1 (Scheme 4). Indeed, the
᎐
Scheme 4
J. Chem. Soc., Dalton Trans., 2000, 2279–2286
2283

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with a different regioselectivity from those obtained using
trans-RuCl2(PPh3)(pnp) [pnp = NPr(C2H4PPh2)2].10 We have
sought to demonstrate formation of possible intermediates by
alternative syntheses, taking advantage of the presence of the
chloride ligand in 2 and its ability to be replaced by alkynyl
groups by means of reactions with alkali metal or silver deriv-
atives of the alkynes, the latter being chosen to facilitate
removal of chloride as insoluble AgCl.
Experimental
General reaction conditions
Reactions were carried out under an atmosphere of nitro-
gen, but no special precautions were taken to exclude
oxygen during work-up. Common solvents were dried and dis-
tilled under nitrogen before use. Light petroleum refers to a
fraction of bp range 60–80 ЊC. Elemental analyses were per-
formed by the Canadian Microanalytical Service, Delta, B.C.,
Canada. Preparative TLC was carried out on glass plates
(20 × 20 cm) coated with silica gel (Merck 60 GF254, 0.5 mm
thickness).
Scheme 5
Instrumentation
ate similar to that shown in Scheme 5, which then undergoes an
internal oxidative addition to the metal centre to give hydrido–
alkynyl intermediate C. This is followed by coupling of the
alkynyl and η2-alkyne moieties, insertion of a second molecule
IR: Perkin-Elmer 1720X FT IR. NMR: Bruker CXP300 or
ACP300 (1H at 300.13 MHz, 13C at 75.47 MHz) or Varian
Gemini 200 (1H at 199.8 MHz, 13C at 50.29 MHz) spectro-
meters. Unless otherwise stated, spectra were recorded using
solutions in CDCl3 in 5 mm sample tubes. FAB mass spectra:
VG ZAB 2HF (using 3-nitrobenzyl alcohol as matrix, exciting
gas Ar, FAB gun voltage 7.5 kV, current 1 mA, accelerating
potential 7 kV). ES mass spectra: Finnegan LCQ. Solutions
were directly infused into the instrument. Chemical aids to
ionisation were used as required.16
᎐
of HC᎐CSiMe into the Ru–H bond of C, followed by coupling
᎐
3
of the resulting vinyl with the terminal vinyl moiety to afford 8
(Scheme 6).
Conclusion
This work has demonstrated a novel series of stepwise reactions
of alkynes with the neutral ruthenium vinylidene complexes
Reagents
RuCl(᎐C᎐CHR)(PPh )Cp* which result in a series of com-
᎐ ᎐
3
plexes containing ligands derived from between two and four
alkyne molecules. Direct trimerisation or cyclotrimerisation of
alkynes does not occur. Instead, individual steps involving
single coupling of two alkyne-derived ligands are involved.
These reactions appear to proceed by stepwise insertions of the
alkyne into Ru–C σ bonds or by coupling of two alkynes at the
ruthenium centre. In some cases, isomerisation of the alkyne to
the corresponding vinylidene may precede these reactions. The
mechanistic complexity of reactions of this type is further illus-
trated by the fact that the products described above are formed
RuCl(PPh ) Cp*,2 RuCl(᎐C᎐CHPh)(PPh )Cp*,1 and RuCl{᎐C᎐
᎐ ᎐
᎐ ᎐
3
2
3
CH(CO2Me)}(PPh3)Cp*7 were prepared by literature methods;
᎐
HC᎐CCO R (R = Me or Et) was obtained by esterification of
᎐
2
propiolic acid (Aldrich).
Reactions of RuCl(᎐C᎐CHPh)(PPh )Cp* 2
᎐ ᎐
3
᎐
(a) With HC᎐CPh/NaOMe. A mixture of RuCl(᎐C᎐CHPh)-
᎐
᎐ ᎐
᎐
(PPh )Cp* (100 mg, 0.157 mmol) and HC᎐CPh (32 mg, 0.314
᎐
3
mmol) in MeOH (20 ml) was treated with an excess of NaOMe
Scheme 6
2284
J. Chem. Soc., Dalton Trans., 2000, 2279–2286

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[from Na (0.92 g) in MeOH (2 ml)], after which the solution
slowly changed from red to yellow. Cooling (0 ЊC) gave a yellow
(CO2Me)}(PPh3)Cp* (365 mg, 0.6 mmol) in thf (40 ml). After
stirring for 4 h at r.t. in the dark, the red solution was filtered
through alumina, evaporated in vacuo and an acetone extract of
the residue purified by preparative TLC (acetone–hexane 1:4).
The major brown band (Rf 0.58) was extracted with acetone
3
᎐
precipitate of Ru{η -PhCHCHC᎐CPh(C᎐CPh)}(PPh )Cp* 1
᎐
᎐
3
(84 mg, 67%). Found: C, 77.30; H, 5.89. Calc. for C52H47PRu:
1
C, 77.68; H, 5.85%. IR (Nujol): ν(CC) 2181 cmϪ1. H NMR
1
᎐
(CDCl3): δ 1.36 [d, J(HP) 1.4, 15 H, Cp*], 3.02 [dd, J(HH) 9,
and gave Ru{η -C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* 3 as a
᎐
᎐
3
J(HP) 14, 1 H, ᎐CH], 3.38 [dd, J(HH) 9, J(HP) 3.7 Hz, 1 H,
red-brown solid (288 mg, 71%), identified by comparison with
the compound prepared as above.
᎐
᎐CH] and 6.98–7.69 (m, 30 H, Ph). 13C NMR (CDCl3): δ 9.76
᎐
᎐
(s, C Me ), 86.21 (s, ᎐CPh), 92.12 (s, C Me ), 95.42 (s, CCPh),
᎐
5
5
5
5
(b) With ethynylbenzene and sodium methoxide. A solution of
124.0–131.0 (m, Ph), 96.3, 114.00, 192.50 (C3 chain). FAB mass
spectrum (m/z): 804, Mϩ; 727, [M Ϫ Ph]ϩ; 679, [M Ϫ C4Ph ?]ϩ;
601, [Ru(CCPh)(PPh3)Cp*]ϩ; 542, [M Ϫ PPh3]ϩ; 499, [Ru-
(PPh3)Cp*]ϩ. Selected lit. values:6 1H NMR δ 1.36 (s, Cp*), 3.00
RuCl{᎐C᎐CH(CO Me)}(PPh )Cp* (62 mg, 0.1 mmol) and
᎐ ᎐
2
3
᎐
HC᎐CPh (30 mg, 0.3 mmol) in MeOH (7 ml) was treated with a
᎐
slight excess of NaOMe and stirred for 30 min at r.t., after
which time starting complex 4 was no longer present (TLC).
After removal of solvent, the residue was separated (TLC,
acetone–hexane 1:4) into four fractions, all containing small
amounts of material. Products from the bands with Rf 0.58
and 0.46 were identified as 3 (5 mg, 18%) and 1 (15 mg, 18%),
respectively.
[dd, J(HH) 8, J(HP) 14, ᎐CH], 3.68 [dd, J(HH) 8.8, J(HP) 3.7
᎐
Hz, CH] and 7.0–7.8 (m, Ph); 13C NMR δ 10.8 (C5Me5), 93.4
(C5Me5), 96.4, 114.8, 125.3, 192.6 (carbon chain).
᎐
᎐
᎐
(b) With LiC᎐CPh. LiC᎐CPh (24 mg, 0.24 mmol) in thf (2
᎐
ml) was added to RuCl(᎐C᎐CHPh)(PPh )Cp* (100 mg, 0.162
᎐ ᎐
3
mmol) in the same solvent (10 ml) cooled to Ϫ55 ЊC. After
warming to r.t. and stirring for 1 h, evaporation and chrom-
atography of the residue (alumina column) afforded complex 1
1
᎐
Reactions of Ru{ꢀ -C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* 3
᎐
᎐
3
1
᎐
(a) With methyl propiolate. A mixture of Ru{η -C(C᎐
CPh)᎐CHC(O)OMe-O}(PPh )Cp* (38 mg, 0.06 mmol) and
HC᎐CCO Me (10 mg, 0.12 mmol) was heated in refluxing
᎐
(30 mg, 24%). A similar reaction between RuCl(᎐C᎐CHPh)-
᎐ ᎐
᎐
3
᎐
(PPh )Cp* (200 mg, 0.324 mmol) and LiC᎐CPh (70 mg, 0.64
᎐
3
᎐
᎐
2
mmol) in thf (20 ml) was treated by preparative TLC (acetone–
hexane 1:4) to give 1 (64 mg, 26%).
hexane (20 ml) for 3 h. Separation of the major product by
preparative TLC afforded Ru{η1,η2-C(CO Me)᎐CHCPh᎐
᎐
᎐
2
C᎐C᎐CH(CO Me)}(PPh )Cp* 6 (38.2 mg, 89%), contained in
the red band (Rf 0.57). Dark red crystals were obtained from
CH2Cl2–MeOH. Found: C, 68.66; H, 5.77. Calc. for C44H43-
᎐ ᎐
2
3
(c) With silver methyl propiolate. A solution of RuCl(᎐C᎐
᎐ ᎐
CHPh)(PPh3)Cp* (300 mg, 0.48 mmol) in thf (30 ml) was
᎐
treated with AgC᎐CCO Me (92 mg, 0.48 mmol) and the mix-
᎐
2
᎐
O PRu: C, 68.84; H, 5.61%. IR (cyclohexane): ν(C᎐C) 1953w,
᎐
4
ture stirred at r.t. for 2 h. The filtered solution (alumina) was
evaporated and an acetone extract separated by preparative
ν(CO) 1781m, 1723m, 1690s cmϪ1. 1H NMR (CDCl3): δ 1.56 [d,
J(HP) 1.2, 15 H, Cp*], 3.29, 3.33 (2 × s, 2 × 3 H, CO2Me), 4.49
[d, J(HP) 1.5, 1 H, CH], 6.92–7.51 (m, 20 H, Ph) and 7.80
[d, J(HP) 3.8 Hz, 1 H, CH]. ES mass spectrum (MeOH ϩ
NaOMe, m/z): 791, [M ϩ Na]ϩ; 775, [M ϩ Na Ϫ O]ϩ; 691,
[M Ϫ Ph]ϩ; 506, [M Ϫ PPh3]ϩ; 499, [Ru(PPh2)Cp*]ϩ.
TLC to give recovered RuCl(᎐C᎐CHPh)(PPh )Cp* (12 mg, 4%)
᎐ ᎐
3
1
᎐
and Ru{η -C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* 3 (180 mg,
᎐
᎐
3
56%). X-Ray quality crystals were obtained from pentane.
Found: C, 70.18; H, 5.85. Calc. for C40H39O2PRu: C, 70.28; H,
᎐
5.71%. IR (cyclohexane): ν(C᎐C) 2163w, ν(CO) 1724m, ν(C᎐C)
᎐
᎐
1558m cmϪ1. H NMR (CDCl3): δ 1.40 [d, J(HP) 1.2, 15 H,
1
(b) With ethyl propiolate. A similar reaction to (a), using
Cp*], 3.33 (s, 3 H, CO2Me), 6.25 [d, J(HP) 3.2 Hz, 1 H, CH] and
1
᎐
Ru{η -C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* (50 mg, 0.07
᎐
᎐
3
7.17–7.50 (m, 20 H, Ph). 13C NMR (CDCl3): δ 10.82 (s, C5Me5),
1
2
᎐
mmol) and HC᎐CCO Et (14 mg, 0.4 mmol), gave Ru{η ,η -
᎐
2
᎐
52.80 (s, OMe), 86.99 (s, C Me ), 99.05, 100.57 (2 × s, ᎐C),
᎐
5
5
C(CO Et)᎐CHCPh᎐C᎐C᎐CH(CO Me)}(PPh )Cp* 7 (41 mg,
᎐
᎐ ᎐ ᎐
2
2
3
122.97 (s, CH), 127.16–137.17 (m, Ph) and 181.26 (s, CO2Me).
ES mass spectrum (MeOH, m/z): 683, [M Ϫ H]ϩ; 499, [Ru-
(PPh3)Cp]ϩ; 422, [Ru(PPh2)Cp*]ϩ.
72%) as red crystals (from CH2Cl2–MeOH). Found: C, 68.83;
H, 5.88. Calc. for C45H45O4PRu: C, 69.14; H, 5.76%. IR (cyclo-
1
hexane): ν(CO) 1787m, 1699s cmϪ1. H NMR (CDCl3): δ 1.01
(m, 3 H, Me), 1.52 [d, J(HP) 1.6, 15 H, Cp*], 3.37 (s, 3 H,
CO2Me), 3.61 (m, 2 H, OCH2), 4.36 [d, J(HP) 3, 1 H, CH],
6.92–7.52 (m, 20 H, Ph) and 7.69 [d, J(HP) 3.4 Hz, 1 H, CH].
ES mass spectrum (MeOH ϩ NaOMe, m/z): 805, [M ϩ Na]ϩ;
781, [M Ϫ H]ϩ.
(d) With methyl propiolate and sodium methoxide. An excess
of NaOMe was added to a solution of RuCl(᎐C᎐CHPh)-
᎐ ᎐
᎐
(PPh )Cp* (100 mg, 0.16 mmol) and HC᎐CCO Me (40 mg,
᎐
3
2
0.48 mmol) in MeOH (30 ml). After removal of solvent, the
residue was separated by preparative TLC (acetone–hexane
1:4) into several bands. The major product was in a bright
(c) With ethynyltrimethylsilane.
A
mixture of Ru{η1-
C(C᎐CPh)᎐CHC(O)OMe-O}(PPh )Cp* (135 mg, 0.2 mmol)
yellow band (R 0.50) which gave Ru{η3-CH(CO Me)CHC᎐
᎐
f
2
᎐
᎐
᎐
3
᎐
CPh(C᎐CCO Me)}(PPh )Cp* 5 (69.6 mg, 58%) as yellow crys-
᎐
2
3
and ethynyltrimethylsilane (120 mg, 0.6 mmol) was heated in
refluxing hexane (30 ml) for 2 h, after which the solution had
changed from red to dark yellow. Two products were separated
by preparative TLC (acetone–hexane 1:4). The first bright yel-
tals (CH2Cl2–EtOH). Found: C, 68.60; H, 5.52. Calc. for
᎐
C H O PRu: C, 68.84; H, 5.61%. IR (cyclohexane): ν(C᎐C)
᎐
44 43
4
2186m, ν(CO Me) 1706s, ν(C᎐C) 1616w, 1594w cmϪ1. 1H NMR
᎐
2
(CDCl3): δ 1.47 [d, J(HP) 1.4, 15 H, Cp*], 2.27 [dd, J(HH) 7.8,
J(HP) 14.7, 1 H, CH], 3.59 [dd, J(HH) 7.8, J(HP) 3.8, 1 H, CH],
3.70, 3.94 (2 × s, 2 × 3 H, CO2Me) and 7.04–7.35 (m, 20 H, Ph).
13C NMR (CDCl3): δ 9.16 [d, J(CP) 8.5, C5Me5], 50.52, 52.32
low band (R 0.76) contained Ru{η3-CH(CO Me)C(CH᎐CHSi-
᎐
f
2
᎐
Me )C᎐CPhC᎐CSiMe }(PPh )Cp* 8 (21 mg, 12%), obtained as
᎐
᎐
3
3
3
yellow crystals from hexane. Found: C, 67.89; H, 7.09. Calc. for
᎐
C H O PRuSi : C, 68.26; H, 6.71%. IR (cyclohexane): ν(C᎐C)
᎐
50 59
2
2
᎐
(2 × s, CO Me), 79.43, 94.05 (2 × s, C᎐C), 93.67 (s, C Me ),
2115m, ν(CO) 1699s cmϪ1. H NMR (CDCl3): δ Ϫ0.23, 0.46
(2 × s, 2 × 9H, SiMe3), 1.47 [d, J(HP) 1.2, 15 H, Cp*], 3.59 (s,
3 H, CO2Me), 5.46 [d, J(HH) 18.9, 1 H, CH], 6.66 [d, J(HH)
18.9 Hz, 1 H, CH] and 6.59–7.26 (m, 21 H, Ph ϩ CH). ES
mass spectrum (MeOH, m/z): 880, Mϩ; 618, [M Ϫ PPh3]ϩ; 603,
[M Ϫ PPh3 Ϫ Me]ϩ; 547, [M Ϫ PPh3 Ϫ SiMe3]ϩ. The second
product was contained in a yellow band (Rf 0.64) and obtained
as a yellow oil, unstable towards chromatography and in solu-
1
᎐
2
5
5
124.58–139.33 (m, Ph), 112.11, 139.33, 155.55, 174.73 (C4
chain) and 217.0 (s, CO2Me). ES mass spectrum (MeOH ϩ
NaOMe, m/z): 791, [M ϩ Na]ϩ; 767, [M Ϫ H]ϩ; 736, [M Ϫ
H Ϫ OMe]ϩ. A brown band (Rf 0.58) contained complex 3 (5.7
mg, 5.3%).
Reactions of RuCl{᎐C᎐CH(CO Me)}(PPh )Cp* 4
᎐ ᎐
2
3
(a) With silver phenylacetylide. Silver phenylacetylide (188
mg, 0.9 mmol) was added to a solution of RuCl{᎐C᎐CH-
tion. This was tentatively identified as Ru{η3-CH(CO2Me)-
CHC᎐CPh(C᎐CSiMe )}(PPh )Cp* 9. IR (cyclohexane):
᎐
᎐ ᎐
᎐
᎐
3
3
J. Chem. Soc., Dalton Trans., 2000, 2279–2286
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Table 2 Crystal data and refinement details for complexes 1, 3, 5, 6, 7 and 8
Compound
Formula
1
3
5
6
7
8
C52H47PRu
C40H39O2PRuؒ
0.5C5H12
719.9
C44H43O4PRu
C44H43O4PRu
C45H45O4PRu
C50H59O2PRuSi2ؒ
C6H12
966.4
M
804.0
767.9
767.9
781.9
Crystal system
Space group
Monoclinic
P21/c
Monoclinic
C2/c
Triclinic
P1
Triclinic
P1
Triclinic
P1
Triclinic
P1
¯
¯
¯
¯
a/Å
b/Å
c/Å
α/Њ
β/Њ
10.386(4)
20.927(6)
37.598(14)
38.14(2)
9.478(4)
21.88(2)
18.013(6)
10.666(5)
10.382(2)
108.41(3)
95.62(3)
91.70(3)
1880
22.569(5)
18.155(4)
9.376(3)
76.66(2)
83.89(2)
84.74(2)
3708
22.793(16)
18.423(19)
9.378(7)
76.63(7)
83.96(6)
84.66(7)
3800
10.9167(8)
16.7444(11)
16.9819(12)
63.452(1)
78.627(1)
84.008(1)
2721.9
90.31(3)
109.66(7)
γ/Њ
V/Å3
Z
8172
8
1.307
7500
8
1.275
2
4
4
2
Dc/g cmϪ3
1.356
1.375
1.366
1.179
Crystal size/mm 0.65 × 0.10 × 0.19
0.15 × 0.28 × 0.25
1.07, 1.14
4.9
0.35 × 0.22 × 0.10
1.05, 1.12
5.0
0.14 × 0.35 × 1.00
1.06, 1.19
5.1
0.19 × 0.23 × 0.80
1.07, 1.18
5.0
0.50 × 0.38 × 0.16
1.16, 1.32
4.0
A* (min., max.)
1.04, 1.08
4.6
50
µ/cmϪ1
2θmax/Њ
50
50
55
50
58
Ntot
N(Rint
No
13704
6593 (0.060)
237?
0.046
0.050
0.43
29528
16979 (0.054)
11325
0.060
0.073
26629
13344 (0.048)
8094
0.048
0.056
31670
13266 (0.026)
9394
0.041
0.050
)
14096
8357
0.052
0.052
0.9
6613
4988
0.049
0.053
1.1
R
Rw
|∆ρmax|/e ÅϪ3
1.9
1.4
0.65(2)
ν(C᎐C) 2144w, ν(CO) 1707m cmϪ1. 1H NMR (CDCl3): δ Ϫ0.74
᎐
᎐
Acknowledgements
We thank the Australian Research Council for support of this
work and Johnson Matthey plc, Reading, UK, for a generous
loan of RuCl3ؒnH2O.
(s, 9 H, SiMe3), 1.66 (s, 15 H, Cp*), 3.53 (s, 3 H, CO2Me) and
6.71–7.83 (m, 20 H, Ph). ES mass spectrum (MeOH ϩ NaOMe,
m/z): 805, [M ϩ Na]ϩ; 782, Mϩ; 520, [M Ϫ PPh3]ϩ; 505,
[M Ϫ PPh3 Ϫ Me]ϩ; 449, [M Ϫ PPh3 Ϫ SiMe3]ϩ.
Structure determinations
References
1 M. I. Bruce, B. C. Hall, N. N. Zaitseva, B. W. Skelton and A. H.
White, J. Organomet. Chem., 1996, 522, 307.
2 M. I. Bruce, B. C. Hall, N. N. Zaitseva, B. W. Skelton and A. H.
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4 C. S. Yi and N. Liu, Organometallics, 1996, 15, 3968.
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Room-temperature single counter diffractometer data sets (T
ca. 295 K; 2θ–θ scan mode, 2θmax as specified; monochromatic
Mo-Kα radiation, λ = 0.71073 Å) were measured to the specified
level of redundancy, Ntotal reflections (where other than unique)
being merged after gaussian absorption correction, to N unique
(Rint cited where appropriate), No with I > 3σ(I) being used in
the full matrix least squares refinement on |F|, minimising Σw∆2
and refining anisotropic thermal parameters for the non-
hydrogen atoms, (x, y, z, Uiso)H being constrained at estimates.
Conventional residuals R, Rw (statistical weights) are quoted at
convergence. Neutral atom complex scattering factors were
employed, computation using the XTAL 3.4 program system.17
Pertinent results are given in Tables 1 and 2 and Figures, the
latter showing 20% thermal ellipsoids for the non-hydrogen
atoms, hydrogen atoms having arbitrary radii of 0.1 Å. Indi-
vidual variations in procedures, abnormalities, idiosyncrasies,
etc., are cited below.
10 C. Bianchini, P. Innocenti, M. Peruzzini, A. Romerosa and F.
Zanobini, Organometallics, 1996, 16, 272.
11 H. Werner, M. Schäfer, J. Wolf, K. Peters and H. G. von Schnering,
Angew. Chem., 1995, 107, 213; Angew. Chem., Int. Ed. Engl., 1995,
34, 191.
Complex 3. Difference map residues are modelled as pentane
solvate disordered about a crystallographic inversion centre,
constrained geometry, isotropic carbon thermal parameter
forms. A hemisphere of data was measured.
12 A. D. Burrows, M. Green, J. C. Jeffery, J. M. Lymnam and
M. F. Mahon, Angew. Chem., 1999, 111, 3228; Angew. Chem., Int.
Ed., 1999, 38, 3043.
13 M. I. Bruce, B. C. Hall, B. W. Skelton, E. R. T. Tiekink, A. H. White
and N. N. Zaitseva, Aust. J. Chem., 2000, 53, 99.
Complexes 6, 7. These are isomorphous and were refined in
the same coordinate and cell setting. Full spheres of data were
measured for both.
14 I. A. Guzel, M. A. Paz-Sandoval, R. Torres-Lubián and P. Juárez-
Saavedra, Acta Crystallogr., Sect. C, 1999, 55, 1090.
15 M. I. Bruce, R. C. F. Gardner, J. A. K. Howard, F. G. A. Stone,
M. Welling and P. Woodward, J. Chem. Soc., Dalton Trans., 1977,
621.
16 W. Henderson, J. S. McIndoe, B. K. Nicholson and P. J. Dyson,
J. Chem. Soc., Dalton Trans., 1998, 519.
17 S. R. Hall, G. S. D. King and J. M. Stewart (Editors), The XTAL 3.4
Users’ Manual, University of Western Australia, Lamb, Perth,
1995.
Complex 8. A full sphere of CCD area detector data was
measured (Bruker AXS instrument, T ca. 300 K), ‘empirical’/
multiscan absorption correction being applied. Difference map
residues were modelled as hexane, carbon thermal parameter
forms isotropic, constrained geometries.
CCDC reference number 186/1965.
See http://www.rsc.org/suppdata/dt/b0/b001981j/ for crystal-
lographic files in .cif format.
2286
J. Chem. Soc., Dalton Trans., 2000, 2279–2286