Some ruthenium complexes derived from 1,4-diethynylbenzene: Molecular structure of Ru{η3-C[=C(CN)2]C(C6H 4C≡CH-4)=C(CN)2}(PPh3)Cp

Article abstract of DOI:10.1016/S0022-328X(99)00487-8

Reactions of Ru(C≡CC₆H₄C≡CR-4)(PPh₃) ₂Cp [R = SiMe₃ (1), H (3)] are described. With Co₂(CO)₈ reactions occur at the C≡C triple bond furthest from the ruthenium centre; in contras

Full text of DOI:10.1016/S0022-328X(99)00487-8

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 592 (1999) 74–83
Some ruthenium complexes derived from 1,4-diethynylbenzene:
molecular structure of
Ru{h3-C[ꢀC(CN)2]C(C6H4CꢁCH-4)ꢀC(CN)2}(PPh3)Cp
Michael I. Bruce a,*, Ben C. Hall a, Paul J. Low a, Brian W. Skelton b, Allan H. White b
a Department of Chemistry, Uni6ersity of Adelaide, Adelaide SA 5005, Australia
b Department of Chemistry, Uni6ersity of Western Australia, Nedlands WA 6907, Australia
Received 23 June 1999; accepted 8 August 1999
Abstract
Reactions of Ru(CꢁCC6H4CꢁCR-4)(PPh3)2Cp [R=SiMe3 (1), H (3)] are described. With Co2(CO)8 reactions occur at the CꢁC
triple bond furthest from the ruthenium centre; in contrast, tetracyanoethene gave Ru{h3-C[ꢀC(CN)2]C(C6H4CꢁCR-
4)ꢀC(CN)2}(PPh3)Cp (R=SiMe3, H), the molecular structure of the latter being determined. Protonation or methylation of 3
occurs at Cb to give the expected vinylidene complexes. With 3, metallation (LiBu), Sonogashira and oxidative coupling reactions
were demonstrated. Coupling with appropriate metal substrates gave a variety of complexes containing RuCꢁCC6H4CꢁCM
(M=W, Rh, Ir, Pt, Au, Hg) moieties. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Ruthenium; 1,4-Diethynylbenzene; Cobalt; Vinylidene
are relatively rare [13], largely because of the difficulty
in preparing suitable precursor complexes {MLn}ꢂ
CꢁCꢂYꢂCꢁCH. For instance, attempts to remove a
single SiMe3 group from the readily available
Me3SiCꢁCCꢁCSiMe3 lead to mixtures of products [14].
Our own interests in the chemistry of the Ru(PR3)2Cp
and related systems has recently led us to make several
derivatives of this dialkyne: these studies are reported
below.
1. Introduction
The electronic properties and structures of metal
centres linked by unsaturated carbon chains is a topic of
much current interest [1–4]. Such links can also be
achieved by combinations of alkynyl groups and unsat-
urated cyclic systems, such as aryl or heterocyclic groups,
particularly thiophenes [5]. In addition, the consequences
of introducing two or more alkynyl groups on an organic
substrate on the chemistry of these systems is also of
interest. In this connection, the prototypical dialkyne is
1,4-diethynylbenzene, 1,4-(HCꢁC)2C6H4. Over the past
two decades, homobinuclear derivatives of most of the
transition metals have been described, those of most
interest containing metals of Groups 8–11 [6–10].
Among these, some have been shown to possess appre-
ciable non-linear optical properties [11], while unusual
luminescent complexes containing copper or silver clus-
ters linked by the CꢁCC6H4CꢁC group have been
described [12]. Heterometallic systems of this type
2. Results and discussion
We have recently described the ready displacement of
SiMe3 from trimethylsilyl-substituted alkynes in their
reactions with RuCl(PPh3)2Cp, carried out in methanol
in the presence of potassium fluoride [15]. This reaction
has afforded either of the complexes Ru(CꢁCC6-
H4CꢁCSiMe3)(PPh3)2Cp(1;Scheme1)or{Ru(PPh3)2Cp}2-
(m-CꢁCC6H4CꢁC) (2), according to stoichiometry. The
SiMe3 group in 1 can be replaced by H in the reaction
with [NBu4]F [16], from which yellow Ru(CꢁCC6H4Cꢁ
CH)(PPh3)2Cp (3) was obtained in 89% yield. Character-
istic spectroscopic features (Table 1) include w(ꢁCH) and
* Corresponding author. Fax: +618-8303-4358.
E-mail address: michael.bruce@adelaide.edu.au (M.I. Bruce)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00487-8

M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
75
w(CꢁC) bands at 3289 and 2071 cm−1, respectively,
singlet Cp resonances at lH 4.35 and lC 85.34, and the
acetylenic carbons at l 54.50, 94.93, 115.08 and 115.78.
The electrospray (ES) mass spectrum of a solution with
added NaOMe contained [M+Na]+ at m/z 839. Com-
plex 1 can be regenerated from 3 by treatment with
LiBun and SiClMe3, in 89% yield, indicating that the
remaining ꢁCH group can be metallated readily and is
thus a potential source of many related complexes.
Reactions between 1 or 3 and Co2(CO)8 afforded the
expected adducts Co2{m-h2-RC2CꢁC[Ru(PPh3)2Cp]}-
(CO)6 [R=SiMe3 (4), H (5)] as dark green crystalline
solids. The IR spectra contained w(CO) bands between
2065 and 2018 cm−1 and, for 4 only, a w(CꢁC) absorp-
tion at 2084 cm−1. In 4, the SiMe3 group gave signals
at lH 0.07 and lC 0.92, while in 5, the ꢁCH proton
resonance was at l 1.26. Singlet Cp resonances were
found at lH 4.33 and 4.30 and at lC 85.41 and 85.44,
respectively. The acetylenic carbon resonances are
found between l 84.26 and 115.68. For 5, the CO
groups resonated as a singlet at l 212.74. The ES mass
spectra contained M+ at m/z 1101 (for 4) and [M+
Na]+ at m/z 1197 (for 5). While these data do not
unequivocally indicate the site of addition, we suggest
that it is the least hindered CꢁCR group which is
attached to the Co2(CO)6 fragment.
complexes is cycloaddition of tetracyanoethene to the
CꢁC triple bond to give a cyclobutenyl complex, which
may undergo subsequent ring-opening to give a buta-
1,3-dien-3-yl derivative, which in turn may displace a
2-e ligand from the metal centre to give an h3-enyl
complex [17,18]. The reactions of 1 and 3 with tetracya-
noethene both proceed readily at ambient temperature
to give deep green solutions, which turn orange–yellow
when heated. Both isolated products were obtained
as yellow crystals and were identified as the h3-enyl
complexes Ru{h3-C(CN)2C(C6H4CꢁCH-4)CꢀC(CN)2}-
(PPh3)Cp [R=SiMe3 (6), H (7)]. The loss of one PPh3
ligand suggested by the elemental analyses was confi-
rmed by the ES mass spectra, which showed [M+Na]+
ions at m/z 776 and 704, respectively. The spectra also
contained aggregate ions formed by clustering of two or
three molecules of the complex about the Na+ ion. In
their IR spectra, w(CN) bands were found between 2223
and 2162 cm−1 and w(CꢁC) bands around 2140 cm−1
.
The NMR spectra also confirmed that there was only
one PPh3 ligand present. In addition, characteristic
singlet Cp resonances were found in the 1H- and
13C-NMR spectra; for 6, the SiMe3 group gave signals
at lH 0.26 and lC −0.24, while the ꢁCH proton
signal was at l 3.23. In 7, the acetylenic carbons were
A characteristic reaction of transition metal alkynyl
found between
l
110.96 and 115.61, the CN
Scheme 1.

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M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
Table 1
Analytical and spectroscopic data
Complex, analysis
IR (cm−1
)
NMR (CDCl3)
Mass spectrum (m/z)
3 Ru(CꢁCC6H4CꢁCH)(PPh3)2Cp
Found: C, 73.87; H, 5.21,
(Nujol): w(ꢁCH) 3289ms,
w(CꢁC) 2071s
1H-NMR: l 3.10 (s, 1H, ꢁCH),
4.35 (s, 5H, Cp), 7.0–7.50
(m, 30H, aromatic H)
(MeOH, with NaOMe):
839, [M+Na]+
C
51H40P2Ru, calc.: C, 73.57; H,
13C-NMR: l 54.50 (s, C4), 94.93
(s, C2), 85.34 (s, Cp), 115.08 (s,
C3), 115.78 (s, C1), 127.21–139.71
(m, PPh3 and C6H4)
5.23; M, 816
4 Co2{m-h2-SiMe3C2C6H4CꢁC-
[Ru(PPh3)2Cp]}(CO)6
Found: C, 61.11; H, 3.93.
C60H48Co2O6P2RuSi calc.: C,
61.33; H, 4.12; M, 1174
(CH2Cl2): w(CꢁC) 2084m
w(CO) 2065m, 2048s,
2018m
1H-NMR: l 0.07 (s, 9H, SiMe3),
4.33 (s, 5H, Cp), 7.06–7.48
(m, 34H, aromatic)
(MeOH): 1101, [M]+; 718,
[M–C2SiMe3–Co2(CO)6]+
13C-NMR: l 0.92 (s, SiMe3), 85.41
(s, Cp), 91.50, 115.68 (2×s, CꢁC),
127.22–139.35 (m, C6H4 and
PPh3)
5 Co2{m-h2-HC2C6H4CꢁC-
[Ru(PPh3)2Cp]}(CO)6
(CH2Cl2): w(CꢁC) 2084m
w(CO) 2065m, 2048s, 2018s
1H-NMR: l 1.26 (s, 1H, ꢁCH), 4.30 (MeOH, with NaOMe):
(s, 5H, Cp), 7.16–7.47
1197, [M+Na]+
Found: C, 63.71; H, 3.93,
C57H40Co2P2Ru·C6H6 calc.: C,
64.13; H, 3.93; M, 1102
(m, 34H, aromatic)
13C-NMR: l 84.26 (s, C2), 85.44
(s, Cp), 103.33 (C2), 113.17 (s,
C2), 127.22–139.37 (m, C6H4 and
PPh3), 212.74 (s, CO)
6 Ru{h3-C[ꢀC(CN)2]C(C6H4CꢁC-
SiMe3)ꢀC(CN)2}(PPh3)Cp
(Nujol): w(CN) 2223s, 2162m, 1H-NMR: l 0.26 (s, 9H, SiMe3),
MeOH, with added NaOMe):
1531, [2M+Na]+; 776,
[M+Na]+
w(CꢁC) 2147w
4.75 (s, 5H, Cp), 7.26–7.57
(m, 19H, aromatic)
Found: C, 66.24; H, 4.58; N, 7.43.
C42H33N4PRuSi calc.: C, 66.83; H,
4.41; N, 7.43; M, 754
13C-NMR: l −0.24 (s, SiMe3), 6.99
(s, C2), 65.70 (s, C4), 85.27 (s,
C1), 92.34, (s, Cp), 97.73 (S,
CꢁC), 103.95 (s, CꢁC), 115.61 (s,
CN), 118.43 (s, CN), 118.57 (s,
CN), 118.69 (s, CN),
124.37–134.62
(m, C6H4 and PPh3), 220.35 (s,
C3)
7 Ru{h3-C[ꢀC(CN)2]C(C6H4CꢁC-
H)ꢀC(CN)2}(PPh3)Cp
(CH2Cl2): w(CN) 2220s,
2199m, 2177m, w(CꢁC)
2110m
1H-NMR: l 3.23 (s, 1H, ꢁCH), 4.77 (MeOH, with added NaOMe):
(s, 5H, Cp), 7.45–7.56 (m, 19H,
aromatic)
2067, [3M+Na]+; 1386,
Found: C, 66.95; H, 3.70; N, 8.03.
[2M+Na]+; 704, [M+Na]+
13C-NMR: l 6.97 (s, C2), 65.47
(s, C4), 82.62 (s, C1), 92.36 (s,
Cp), 110.96 (s, CꢁC), 115.61 (s,
CꢁC), 118.38 (s, CN), 118.52 (s,
CN), 118.70 (s, CN),
C
39H25N4PRu·MeOH calc.: C,
67.21; H, 4.09; N, 7.85; M, 682
124.25–134.62
(m, C6H4 and PPh3)
9 Ru{ꢀCꢀCH(C6H4CꢁCH)}-
(PPh3)2Cp][PF6]
(Nujol): w(CꢀC) 1675m,
1630m, 1591m
1H-NMR: l 3.15 (s, 1H, ꢀCHR),
3.71 (s, 1H, ꢁCH), 5.40 (s, 5H,
Cp), 7.04–7.78 (m, 3H, aromatic)
(MeOH): 817, [M–PF6]+
429, [Ru(PPh3)Cp]+
;
Found: C, 63.55; H, 4.46
C
51H41F6P3Ru·MeOH calc.: C,
13C-NMR: l 92.20 (s, Cd), 95.46
(s, Cp), 111.84 (s, Cx), 119.53 (s,
Cg), 126.68–133.99 (m,
63.68; H, 4.29; M, 962 (cation)
Ph+C6H4), 273.09 [t, J(CP) 69,
Ca]
10 Ru{ꢀCꢀCMe(C6H4CꢁCH)}-
(PPh3)2Cp][OTf]
Found: C, 63.37; H, 3.60
C52H43F6O3P2RuS·0.5CH2Cl2
calc.: C, 62.81; H, 4.30; M, 980
(cation)
(Nujol): w(CꢀC) 1661m,
1546m, (OTf) 1273m
1H-NMR: l 1.91 (s, 3H, Me), 3.04
(s, 1H, ꢁCH), 5.17 (s, 5H, Cp),
6.88–7.41 (m, 34H, aromatic)
(MeOH): 831,
[M–PPh3–CF3SO3]+
569, [M–PPh3]+
;
13C-NMR: l 11.84 (s, Me), 83.10
(s, Cp), 94.47 (s, C), 95.46 (s, C),
121.37–134.39 (m, Ph)

M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
77
Table 1 (Continued)
Complex, analysis
IR (cm−1
)
NMR (CDCl3)
Mass spectrum (m/z)
1
11 Ru{CꢁCC6H4CꢁCPh)}(PPh3)2Cp] (Nujol): w(CꢁC) 2148m, 2065m H-NMR: l 4.46 (s, 5H, Cp),
(MeOH): 888, M+
630, [M–PPh3]+
;
Found: C, 72.43; H, 5.21
57H44P2Ru·0.5PhI calc.: C, 72.50;
7.10–7.72 (m, 34H, aromatic)
13C-NMR: l 85.64 (s, Cp), 106.18 (s,
CꢁC), 127.78–134.46 (m, Ph and
C6H4)
C
H, 4.71; M, 892
12 1,4{Ru(PPh3)2Cp(CꢁC)}2C6H4
Found: C, 68.24; H, 4.93
C102H78P4Ru2·2.5CH2Cl2 calc.: C,
68.13; H, 4.54; M, 1630
(Nujol): w(CꢁC) 2067s
(MeOH): 1630, M+
13 {Cp(OC)3W}(m-CꢁCC6H4CꢁC)
{Ru(PPh3)2Cp}
Found: C, 62.01; H, 4.41
C59H44O3P2RuW calc.: C, 61.74; H,
3.86; M, 1148
(Nujol): w(CꢁC) 2070m, w(CO) 1H-NMR: l 4.31 (s, 5H, RuCp),
(MeOH, with added NaOMe):
2034m, 1951m (br)
5.63 (s, 5H, WCp), 7.06–7.46
(m, 34H, aromatic)
1170, [M+Na]+; 1148, [M]+
13C-NMR: l 85.16 (s, Cp), 91.63
(s, Cp), 115.14 (s, CC), 121.48
(s, CC), 127.16–139.38 (m, C6H4
and PPh3), 211.48 (s, CO)
14 {Cp(Ph3P)3Ru}(m-CꢁCC6H4CꢁC) (Nujol): w(CꢁC) 2065m w(CO) 1H-NMR: l 4.35 (s, 5H, Cp),
(MeOH): 1505, M+; 1243,
[M–PPh3]+
{Rh(h-O2)(CO)(PPh3)2}
1961s (CO), w(OO) 833m
7.11–7.71 (m, 64H, aromatic)
13C-NMR: l 85.43 (s, Cp), 93.50
(s, CꢁC), 103.37 (s, CꢁC),
127.40–138.90 (m, C6H4 and PPh3),
212.80 (s, CO)
Found: C, 66.62; H, 4.81
C88H69O3P4RhRu·CH2Cl2 calc.: C,
67.33; H, 4.51; M, 1505
15 {Cp(Ph3P)2Ru}(m-CꢁCC6H4CꢁC- (Nujol): w(CꢁC) 2069m w(CO) 1H-NMR: l 4.30 (s, 5H, Cp),
(MeOH): 1631, [M+MeCN]+
{Ir(h-O2)(CO)(PPh3)2}
Found: C, 66.41; H, 4.36
C88H69IrO3P4Ru calc.: C, 66.32; H,
4.37; M, 1594
1953ms w(OO) 833m
7.04–8.30 (m, 64H, aromatic)
13C-NMR: l 85.38 (s, Cp), 97.98
(s, CꢁC), 115.68 (s, CꢁC),
127.38–139.54 (m, C6H4 and PPh3),
211.80 (s, CO)
16 Pt{CꢁCC6H4CꢁC[Ru(PPh3)2Cp}}2 (Nujol): w(CꢁC) 2074s
1H-NMR: l 2.43 (s, 4H, CH2) 4.31 (MeOH, with added Ag+):
(dppe)
(s, 10H, Cp), 6.93–7.49 (m, 88H,
aromatic)
2331, [2M+Ag]+
Found: C, 69.16; H, 4.74
C128H102P6PtRu2 calc.: C, 69.08; H,
4.63; M, 2223
13C-NMR: l 36.26 (s, CH2), 85.16
(s, Cp), 93.42 (s, CꢁC), 103.29
(s, CꢁC), 113.16 (s, CꢁC), 115.26
(s, CꢁC), 127.13–139.44 (m, C6H4
and Ph)
17 {Cp(Ph3P)2Ru}
(Nujol): w(CꢁC) 2068m
1H-NMR: l 4.60 (s, 5H, Cp)
7.20–7.57 (m, 49H, aromatic)
13C-NMR: l 85.42 (s, Cp),
127.59–133.95 (m, C6H4 and Ph)
(MeOH): 1275, M+
(m-CꢁCC6H4CꢁC{Au(PPh3)
Found: C, 65.20; H, 4.40
C69H54P6AuP3Ru calc.: C, 65.04; H,
4.27; M, 1274
18 Hg{CꢁCC6H4CꢁC[Ru{PPh3)2Cp]}2 (Nujol): w(CꢁC) 2068m
Found: C, 70.98; H, 5.09
(MeOH, m/z): 1830, M+
;
429, [Ru(PPh3)Cp]+
C102H78HgP4Ru2 calc.: C, 70.51; H,
4.53; M, 1830
carbons between l 118.38 and 118.70. Final confirmation
of the molecular structure was achieved by a single-crystal
X-ray determination carried out on 7, which showed that,
incontrasttothereactionwithCo2(CO)8, thecyano-olefin
adds to the ruthenium-bonded CꢁC triple bond.
corresponding values for the closely related complex
Ru{h3-C(CF3)2CPhCꢀC(CN)2}(PPh3)Cp (8) [18]. The
metal is coordinated by the h-C5H5 group [Ruꢂ
,
,
C(cp) 2.195(7)–2.237(9), av. 2.22 A] (av. 2.24 A in 8),
,
,
the PPh3 ligand [RuꢂP(1) 2.383(1) A; cf. 2.411(2) A
in 8] and the cyanocarbon ligand [RuꢂC(1), 2.212(6),
2.1. Molecular structure of Ru{p3-C(CN)2C(C6H4Cꢁ
CH-4)CꢀC(CN)2}(PPh3)Cp (7)
RuꢂC(2) 2.118(5), RuꢂC(3) 1.980(7) A; corresponding
,
,
values for 8: 2.202(7), 2.138(7), 1.977(7) A]. The mode
of attachment of this ligand is essentially identical to
that found in 8 and is similar to several other examples
[17,18]. The pattern of CꢂC separations along the chain
is also similar, with values of 1.471(8), 1.422(8) and
A plot of a molecule of 7 is shown in Fig. 1, which also
indicates the atom numbering scheme. Table 2 collects
significant bond distances and angles, together with

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M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
solution of 3 in methanol resulted in a rapid colour
change to cherry red. The reddish–pink solid which
was isolated from the reaction mixture was identified
as the expected vinylidene complex [Ru{ꢀCꢀCH-
(C6H4CꢁCH)}(PPh3)2Cp][PF6] (9). The characteristic
low-field triplet resonance for the RuꢂC atom was
found at l 273.09, while in the 1H-NMR spectrum,
resonances at l 3.15 and 3.71 are assigned to the
vinylidene and ethynyl protons, respectively. In the ES
mass spectrum, [M–PF6]+ is found at m/z 817. Simi-
larly, addition of methyl triflate to 3 afforded pink
[Ru{ꢀCꢀCMe(C6H4CꢁCH)}(PPh3)2Cp][OTf] (10). The
ES mass spectrum contained [M–OTf]+ at m/z 831,
while the ꢁCH and ꢀCMe protons resonated at l 3.04
and 1.91, respectively. In the 13C-NMR spectrum, the
Me and Cp singlets were at l 11.84 and 83.10, respec-
tively; the RuꢂC signal was not observed.
Fig. 1. Plot of
CH)ꢀC(CN)2}(PPh3)Cp (7), showing the atom numbering scheme.
Non-hydrogen atoms are shown with 20% thermal envelopes; hydro-
a
molecule of Ru{h3-C[ꢀC(CN)2]C(C6H4Cꢁ
,
gen atoms have arbitrary radii of 0.1 A.
As described above, metallation of the ethynyl group
in 3 can be achieved with LiBu. Conventional coupling
of the alkyne with iodobenzene, using a combined
palladium(0)/copper(I) catalyst (Sonogashira coupling)
[19] afforded Ru(CꢁCC6H4CꢁCPh)(PPh3)2Cp (11) in
98% yield. This complex was identified by elemental
analysis, from its ES MS (M+ at m/z 888) and from the
NMR spectra, which contained the appropriate reso-
nances. The IR spectrum contained w(CꢁC) bands at
,
1.341(9) A for C(1)ꢂC(2), C(2)ꢂC(3) and C(3)ꢂC(4),
respectively. These values are consistent with an Ru-h2-
C(1)ꢀC(2) interaction and a degree of multiple bonding
in the RuꢂC(3) bond. The substituent at C(2) has
normal CꢂC separations, with C(2)ꢂC(21) 1.497(6),
,
C(24)ꢂC(241) 1.438(7) and C(241)ꢂC(242) 1.159(8) A,
the latter being an unperturbed CꢁC triple bond.
The reactivity of 3 was further investigated with
other electrophiles. Addition of HPF6 to the orange
2148 and 2065 cm−1
.
Oxidative coupling of 3, using dioxygen and a Cu(I)/
tmed catalyst [20], afforded a yellow powder tentative-
ly identified as {Cp(Ph3P)2Ru}(m-CꢁCC6H4CꢁCCꢁ
CC6H4CꢁC){Ru(PPh3)2Cp} (12) from its ES mass spec-
trum, which contained M+ at m/z 1630. The IR spec-
trum contained a w(CꢁC) band at 2067 cm−1; the
compound was not soluble enough for meaningful
NMR spectra to be obtained.
The electronic properties of oligomeric metal-yne
polymers based upon the {MꢂCꢁCC6H4CꢁCꢂ} repeat
unit have recently been theoretically examined [21]. The
synthesis of 2 demonstrates that symmetrical species
containing two ruthenium(II) centres can be obtained
from 3. We have extended these studies to complexes
containing ruthenium linked to tungsten(II), rhodi-
um(I), iridium(I), platinum(II), gold(I) and mercury(II)
moieties (Scheme 2). These materials were made
via copper(I)-catalysed coupling reactions between 3
and WCl(CO)3Cp, MCl(CO)(PPh3)2 (M=Rh, Ir),
PtCl2(dppe) and AuCl(PPh3); the mercury derivative
was obtained directly from 3 and Hg(OAc)2.
Table 2
Selected bond parameters for Ru{h3-C[ꢀC(CN)2]C(C6H4R)ꢀ
C(CN)2}(PPh3)Cp [R=CꢁCH (7), H (8)]
7
8
Bond lengths
RuꢂP
RuꢂC(1)
RuꢂC(2)
RuꢂC(3)
RuꢂC(cp)
(av.)
C(1)ꢂC(2)
C(2)ꢂC(3)
C(2)ꢂC(21)
C(3)ꢂC(4)
C(24)ꢂC(241)
C(241)ꢂC(242)
CꢂCN
2.383(1)
2.212(6)
2.118(5)
1.980(7)
2.195ꢂ2.237(9)
2.22
2.411(2)
2.202(7)
2.138(7)
1.977(7)
2.218–2.273(8)
2.24
1.471(8)
1.422(8)
1.497(6)
1.341(9)
1.438(7)
1.159(8)
1.422–1.444(8)
1.437
1.46(1)
1.42(1)
1.499(9)
1.37(1)
–
–
1.43(1) (×2)
(av.)
CꢂN
(av.)
1.133(8)–1.15(1)
1.143
1.12, 1.13(1)
Bond angles
P(1)ꢂRuꢂC(1)
P(1)ꢂRuꢂC(2)
P(1)ꢂRuꢂC(3)
C(1)ꢂRuꢂC(3)
RuꢂC(1)ꢂC(2)
RuꢂC(2)ꢂC(21)
RuꢂC(3)ꢂC(2)
RuꢂC(3)ꢂC(4)
96.1(5)
115.5(1)
92.3(1)
70.5(2)
66.7(3)
128.0(4)
75.0(4)
146.9(4)
101.0(2)
122.0(2)
98.7(2)
70.3(3)
68.0(4)
130.9(4)
76.0(4)
149.9(6)
The WꢂRu complex {Cp(OC)3W}(m-CꢁCC6H4CꢁC)-
{Ru(PPh3)2Cp} (13) was isolated as a yellow powder
in 90% yield. The IR spectrum contained a w(CꢁC)
band at 2070 cm−1 and two terminal w(CO) bands
at 2034 and 1951 cm−1 as expected for the W(CO)3Cp
group. The two Cp singlets were found at lH 4.31
and 5.63 and at lC 85.16 and 91.63, assigned

M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
79
Scheme 2.
to the RuꢂCp and WꢂCp groups, respectively. The ES
mass spectrum of a solution containing NaOMe con-
tained M+ and [M+Na]+ ions at m/z 1148 and 1170,
respectively.
([M+Ag]+ at m/z 2331) and from the expected reso-
1
nances in the H- and 13C-NMR spectra. This complex
is another example of the now large class of ‘tweezer
complexes’ [23], exemplified by the cis-bis-alkynyl
derivatives of titanium [24] and platinum [25], for ex-
ample.
Ready replacement of the ethynyl hydrogen in 3
by the isolobal Au(PPh3) group gave yellow
{Cp(Ph3P)2Ru}(m-CꢁCC6H4CꢁC){Au(PPh3)} (17). As
expected, the spectroscopic properties of 17 do not
differ much from those of 3, with the exception of the
contributions from the Au(PPh3) group; the w(CꢁC)
absorption is at 2068 cm−1. The ES mass spectrum
contains M+ at m/z 1275.
Direct reaction between 3 and Hg(OAc)2 in THF
solution occurred on heating to give a yellow precipi-
tate, which was purified by chromatography (Al2O3
column). Its insolubility precluded our obtaining NMR
spectra, but a w(CꢁC) at 2068 and M+ at m/z 1830 in
the ES mass spectrum support the proposed structure
of the product as the mercury-bridged complex
Hg{CꢁCC6H4CꢁC[Ru(PPh3)2Cp]}2 (18).
The Group 8/9 complexes were identified as the
dioxygen adducts {Cp(Ph3P)2Ru}(m-CꢁCC6H4CꢁC)-
{M(h-O2)(CO)(PPh3)2} [M=Rh (14), Ir (15)], as
shown by the w(OO) bands around 830 cm−1. Single
w(CO) absorptions at ca. 2065 cm−1 confirmed the
presence of the oxidised M(III) centre. Other spectro-
scopic properties were consistent with the proposed
structures, including M+ at m/z 1505 (14) and
[M+MeCN]+ at m/z 1632 (15). The ready formation
of dioxygen adducts of similar complexes, such
as {Cp(OC)3M}(m - CꢁCCꢁC){M%(h - O2)(CO)(PPh3)2}
(M=Mo, W; M%=Rh, Ir) has been observed previ-
ously [22] and is probably a result of the increased
electron density on the M(I) centre in the alkynyl
complexes.
The reaction between 3 and PtCl2(dppe) afforded the
dialkynyl compound Pt{CꢁCC6H4CꢁC[Ru(PPh3)2-
Cp]}2(dppe) (16) in 90% yield as a yellow powder. The
compound was characterised by microanalysis, from its
ES mass spectrum obtained in the presence of Ag+
The homo- and heterometallic complexes 12–15 and
17 are novel examples of compounds in which an

80
M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
extensive unsaturated carbon-rich chain bridges two
metal centres, or in the case of 16 and 18, two such
chains attached to a single metal centre (Pt, Hg) are
each capped by the ruthenium fragment. The electronic
and optical properties of such extended systems are
currently of great interest and are being investigated.
However, we note that in the related iron complex
{Cp*(dppe)Fe}(m-CꢁCC6H4CꢁC){Fe(dppe)Cp*} [26],
the degree of electronic interaction between the iron
centres, as shown by electrochemical studies, appears to
be considerably less than that found in analogous sys-
tems containing all-carbon links such as C4. In the
present case, preliminary CV data indicate that 2 un-
dergoes two reversible one-electron oxidations.
examined at cone voltages in the range 20–80 V to find
the best conditions. Chemical aids to ionisation are
indicated where used [27].
4.3. Reagents
Complex 1 was prepared as described previously [14].
Copper(I) iodide (Ajax), IrCl3·3H2O and K2[PtCl4]
(Johnson Matthey), triphenylphosphine and RhCl(CO)-
(PPh3)2 (Strem), tetracyanoethene (Fluka) and iodo-
methane (Ajax) were used as received.
4.4. Preparation of Ru(CꢁCC6H4CꢁCH)(PPh3)2Cp (3)
The silylated complex 1 (0.5 g, 0.56 mmol) was
stirred in degassed THF (40 ml) and methanol (10 ml)
with [NBu4]F (0.6 mg, 0.6 mmol) overnight. The sol-
vent was removed under reduced pressure and the
residue passed down an alumina column (3:7 acetone–
hexane). The first yellow fraction was evaporated and
the resulting yellow solid was collected to give
Ru(CꢁCC6H4CꢁCH)(PPh3)2Cp (3) (407 mg, 89%).
3. Conclusions
This work demonstrates the differing reactivities of
the two CꢁC triple bonds in 1 and 3, Co2(CO)8 adding
to the least hindered one, while tcne adds to the ruthe-
nium-bonded and thereby activated one. The use of 3
as a source of heterobimetallic complexes in which a
CꢁCC6H4CꢁC moiety bridges the two metal centres is
shown by syntheses of complexes containing Ru/W,
Ru/Rh. Ru/Ir, Ru/Pt, Ru/Au and Ru/Hg pairs.
4.5. Reactions of Co2(CO)8
4.5.1. With 1
Co2(CO)8 (39 mg, 0.113 mmol) in benzene (10 ml)
was added to complex 1 (100 mg, 0.113 mmol) in
benzene (10 ml). The resulting solution turned dark
green in colour after stirring 30 min at room tempera-
ture (r.t.). The solvent was removed and the resulting
residue was recrystallised from CH2Cl2–n-hexane.
Green crystals of Co2{m-h2-SiMe3C2C6H4CꢁC[Ru-
(PPh3)2Cp]}(CO)6 (4) (89 mg, 71%) were obtained.
4. Experimental
4.1. General conditions
All reactions were carried out under dry, high-purity
nitrogen unless otherwise stated, using standard
Schlenck techniques. Common solvents were dried, dis-
tilled under nitrogen and degassed before use. Light
petroleum refers to a fraction of b.p. 60–80°C. Elemen-
tal analyses were performed by the Canadian Microan-
alytical Service, Delta, BC. Preparative TLC was
carried out on glass plates (20×20 cm) coated with
silica gel (Merck 60 GF254, 0.5 mm thick).
4.5.2. With 3
Similarly, Co2(CO)8 (43 mg, 0.123 mmol) and com-
plex 3 (100 mg, 0.123 mmol) in benzene (20 ml), stirring
for 20 min gave a deep green solid, which was purified
by preparative TLC (3:7 acetone–hexane). The green
band (Rf 0.80) was recrystallised from CH2Cl2–n-hex-
ane to give olive-green crystals of Co2{m-h2-
HC2C6H4CꢁC[Ru(PPh3)2Cp]}(CO)6 (5) (77.4 mg, 57%).
4.2. Instrumentation
Analytical and spectroscopic data are collected in
Table 1. IR spectra were obtained on a Perkin–Elmer
1720X FTIR spectrometer. NMR spectra of solutions
in CDCl3 were recorded on Bruker ACP 300 (1H at
300.13 MHz, 13C at 75.47 MHz) or Varian Gemini 200
(1H at 199.8 MHz, 13C at 50.29 MHz) spectrometers.
Electrospray mass spectra (ES MS) were obtained from
samples dissolved in MeOH unless otherwise indicated.
Solutions were injected into a VG Platform II spec-
trometer via a 10 ml injection loop, or by direct infu-
sion into a Finnegan LCQ instrument. Nitrogen was
used as the drying and nebulising gas. Samples were
4.6. Reactions of tetracyanoethene
4.6.1. With 1
Tetracyanoethene (15 mg, 0.113 mmol) was added to
a solution of 1 (100 mg, 0.113 mmol) in THF (20 ml)
and the mixture was then heated under reflux for 3 h.
Initially the yellow solution turns green, but after the
reflux the solution was orange–yellow. Solvent was
removed and the residue purified by preparative TLC
(3:7 acetone–hexane). An orange–yellow band (Rf
0.65) was crystallised (CH2Cl2–n-hexane) to give yellow

M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
81
crystals
of
Ru{h3-C[ꢀC(CN)2]C(C6H4CꢁCSiMe3)ꢀ
0.123 mmol) gave a yellow powder of {Cp(Ph3P)2Ru}-
(m-CꢁCC6H4CꢁC){Ir(h-O2)(CO)(PPh3)2} (15) (112 mg,
57%).
C(CN)2}(PPh3)Cp (6) (90 mg, 97%).
4.6.2. With 3
Similarly, complex 3 (100 mg, 0.123 mmol) and tcne
(16 mg, 0.123 mmol) in THF (20 ml) were heated under
reflux for 3 h. A bright yellow band (Rf 0.4) gave yellow
crystals of Ru{h3-C[ꢀC(CN)2]C(C6H4CꢁCH)ꢀC(CN)2}-
(PPh3)Cp (7) (57 mg, 68%) from CH2Cl2–MeOH. Crys-
tals suitable for X-ray analysis were grown from
CH2Cl2–hexane.
4.7.6. With PtCl2(dppe)
PtCl2(dppe) (61 mg, 0.092 mmol) was added to a
diethylamine (6 ml)–dmf (4 ml) solution containing 3
(150 mg, 0.184 mmol) and a catalytic amount of CuI
(ca. 4 mg). A yellow precipitate formed in the solution
after 10 min and after a further hour the solvent was
partly removed. Addition of MeOH (10 ml) caused
further precipitation. Filtration gave a yellow powder
of Pt{CꢁCC6H4CꢁC[Ru(PPh3)2Cp}}2(dppe) (16) (67
mg, 33%).
4.7. Reactions of Ru(CꢁCC6H4CꢁCH)(PPh3)2Cp (3)
4.7.1. With HPF6
4.7.7. With AuCl(PPh3)
A few drops of HPF6 were added to a solution of 3
(100 mg, 0.123 mmol) in MeOH (20 ml) and the
mixture was stirred at r.t. for 10 min, after which the
solution turned cherry red. Solvent was removed and
the residue was dissolved in CH2Cl2; the solution was
added dropwise to cold rapidly stirred Et2O to give a
reddish–pink precipitate of [Ru{ꢀCꢀCH(C6H4CꢁCH)}
(PPh3)2Cp][PF6] (9) (101 mg, 85%).
Similarly, a mixture of AuCl(PPh3) (61 mg, 0.123
mmol) with a catalytic amount of copper iodide (ca. 5
mg) in diethylamine (15 ml) was treated with 3 (100 mg,
0.123 mmol). There was immediate formation of a
bright yellow precipitate, which was collected and dried
to give {Cp(Ph3P)2Ru}(m-CꢁCC6H4CꢁC){Au(PPh3)}
(17) (76 mg, 49%).
4.7.8. With Hg(OAc)2
4.7.2. With methyl triflate
A mixture of 3 (100 mg, 0.123 mmol) and Hg(OAc)2
(19 mg, 0.061 mmol) in THF (20 ml) was heated under
reflux for 3 h. The yellow precipitate which formed was
collected, washed with hexane and air dried to give
Hg{CꢁCC6H4CꢁC[Ru(PPh3)2Cp]}2 (18) (50 mg, 45%).
Addition of CF3SO3Me (20 mg, 0.123 mmol) to a
solution of 3 (100 mg, 0.123 mmol) in CH2Cl2 (10 ml)
at r.t.; after 20 min, the solution turned red. Solvent
was removed and the residue was dissolved in CH2Cl2
and added to rapidly stirred cold Et2O, to give a pink
precipitate which was collected and air-dried. This
solid was identified as [Ru{ꢀCꢀCMe(C6H4CꢁCH)}-
(PPh3)2Cp][OTf] (10) (76 mg, 63%).
4.8. Preparation of Ru(CꢁCC6H4CꢁCPh)(PPh3)2Cp (11)
Iodobenzene (100 mg, 0.5 mmol) was added to a mix-
ture of 3 (198 mg, 0.243 mmol), CuI (ca. 4 mg) and
Pd(PPh3)4 (14 mg, 0.012 mmol) in NHEt2 (30 ml). After
2 h stirring at r.t. in the dark, the solution was filtered
into hexane (50 ml) to give a bright yellow precipitate of
Ru(CꢁCC6H4CꢁCPh)(PPh3)2Cp (11) (212 mg, 98%).
4.7.3. With WCl(CO)3Cp
A
mixture of 3 (100 mg, 0.123 mmol) and
WCl(CO)3Cp (45 mg, 0.123 mmol) was stirred vigor-
ously with CuI (ca. 3 mg) in degassed diethylamine (20
ml) in the dark for 1 h. The yellow precipitate was
collected, washed with hexane and dried under vacuum
to give {Cp(OC)3W}(m-CꢁCC6H4CꢁC){Ru(PPh3)2Cp}
(13) (127 mg, 90%).
4.9. Oxidati6e coupling of 3
Addition of tmed (150 ml, 1.01 mmol) to a suspension
of CuCl (100 mg, 1.01 mmol) in acetone (5 ml) gave a
blue–green solution after 15 min. In a separate flask,
dioxygen was passed into a solution of 3 (200 mg, 0.24
mmol) in acetone (40 ml) via a glass frit. The copper cat-
alyst was added dropwise until 3 was no longer present
(TLC). Evaporation and extraction of the residue with
CH2Cl2 left a yellow insoluble material, tentatively iden-
tified as 1,4-{Ru(PPh3)2Cp(CꢁC)}2C6H4 (12) (61 mg,
31%).
4.7.4. With RhCl(CO)(PPh3)2
Similarly, RhCl(CO)(PPh3)2 (85 mg, 0.123 mmol)
was added to 3 (100 mg, 0.123 mmol) in a mixture of
3:1 NHEt2–THF (20 ml) with a catalytic amount of
CuI (ca. 5 mg). After stirring 2 h in the dark, the
resulting solution was then chromatographed on an
alumina column (3:7 acetone–hexane). An intense yel-
low band afforded {Cp(Ph3P)2Ru}(m-CꢁCC6H4CꢁC)-
{Rh(h-O2)(CO)(PPh3)2} (14) as a yellow powder (42
mg, 23%).
4.10. Con6ersion of 3 to 1
4.7.5. With IrCl(CO)(PPh3)2
A similar reaction using IrCl(CO)(PPh3)2 (100 mg,
LiBu (61 ml of a 2 M solution in hexane, 0.122 mmol)
was added to a cold (−78°C) solution of 3 (100 mg,

82
M.I. Bruce et al. / Journal of Organometallic Chemistry 592 (1999) 74–83
0.122 mmol) in THF (20 ml) and the mixture was
stirred for 15 min. Addition of SiClMe3 (15 ml, 0.122
mmol), warming to r.t. and separation of the product
by chromatography on alumina gave 1 (105 mg, 89%).
electrospray mass spectra. Johnson Matthey Technol-
ogy plc, Reading, UK, generously loaned the
RuCl3·nH2O.
References
4.11. Crystallography
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being used. Computation used the XTAL 3.4 program
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4.12. Crystal and refinement data
(7)
Ru{h3-C(CN)2C(C6H4CꢁCH-4)CꢀC(CN)2}-
(PPh3)CpꢁC39H25N4PRu, M=681.7. Monoclinic, space
group P21/c, a=12.351(3), b=14.173(5), c=20.049(5)
3
,
,
A, i=112.30(3)°, V=3247 A , Z=4, zc=1.394
g
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, F(000)=1384. Crystal dimensions: 0.25×
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5. Supplementary material
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC 127304 for compound 7. Copies of
the information can be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge CB2
1EZ, UK (Fax:+44-1223-336-033; e-mail: deposit@
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Acknowledgements
Support of this work by the Australian Research
Council is gratefully acknowledged. B.C.H. and P.J.L.
were the holders of Australian Post-graduate Awards.
We thank Professor Brian Nicholson (University of
Waikato, Hamilton, New Zealand) for some of the
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