Synthesis and reactivity of μ-butadienyl diruthenium cations

Article abstract of DOI:10.1016/S0020-1693(03)00391-8

Propargyl alcohols HC≡CCR₂OH (R=H, Me or Ph) react with [Ru₂(CO)(MeCN)(μ-CO)(μ-CH₂)(η-C ₅H₅)₂] (2) to form the allylidene complexes [Ru₂(CO)(μ-CO){μ-η¹,η³-C(CR ₂OH)CH=CH₂}(η-C₅H₅) ₂] (4a, R=H; 4b, R=Me; 4c, R=Ph). Treatment of complexes 4a-c with HBF₄ removes the hydroxide group as water, giving the 2-butadienyl complexes [Ru₂(CO)(μ-CO)(μ-η²,η ³-CR₂=CCH=CH₂)(η-C₅H ₅)₂][BF₄] (5a, R=H; 5b, R=Me; 5c, R=Ph). The reactivity of 5a-c towards nucleophiles and bases is described. With hydride, 5a-c undergo nucleophilic attack at the C(R₂) carbon to give the allylidene complexes [Ru₂(CO)(μ-CO){μ-η¹, η³-C(CR₂H)CH=CH₂}(η-C₅H ₅)₂] (6a, R=H; 7, R=Me; 11, R=Ph) and, in the case of 5c, the butadiene complex [Ru₂(CO)₂(μ-η ²,η²-CPh₂=CHCH=CH₂)(η-C ₅H₅)₂] (12) and the allene complex [Ru ₂(CO)₂(μ-η²,η²-CPh ₂=C=CHMe)(η-C₅H₅)₂] (13), formally due to attack at the μ-C and CH₂ carbons, respectively. The complexes 5a-c react with methyl lithium to undergo nucleophilic attack predominantly at the C(R₂) carbon, giving methylated allylidene complexes [Ru₂(CO)(μ-CO){μ-η¹,η ³-C(CR₂Me)CH=CH₂}(η-C₅H ₅)₂] (6b, R=Me; 9, R=Me; 14, R=Ph). With 5b and 5c methyl lithium also acts as a base, abstracting protons to give the novel divinylcarbene complex [Ru₂(CO)(μ-CO){μ-η ¹,η³-C(CMe=CH₂)CH=CH₂}(η- C₅H₅)₂] (8) and the μ-butatriene complex [Ru₂(CO)₂(μ-η²,η²- CPh₂=C=C=CH₂)(η-C₅H₅) ₂] (15), respectively. Complexes 8 and 15 are formed exclusively by treating 5b and 5c, respectively, with diazabicyclo[5.4.0]undec-7-ene (DBU). Complexes 8 and 9 were also prepared in good yield by reaction of complex 2 with 2-methyl-1-buten-3-yne {CH₂=C(Me)C≡CH} and t-butylacetylene, respectively. Treatment of complex 8 with HBF₄ resulted in protonation at each of the methylene groups, affording 5b and isomeric [Ru₂(CO)(μ-CO){μ-η²,η ³-CH(Me)=CC(Me)=CH₂}(η-C₅H ₅)₂][BF₄] (10). The structures of 5b, 5c and 8 were established by X-ray diffraction.

Full text of DOI:10.1016/S0020-1693(03)00391-8

Inorganica Chimica Acta 354 (2003) 29Á40
/
www.elsevier.com/locate/ica
Synthesis and reactivity of m-butadienyl diruthenium cations
James N.L. Dennett, Selby A.R. Knox *, Jonathan P.H. Charmant, Amy L. Gillon,
A. Guy Orpen
School of Chemistry, University of Bristol, Bristol BS8 1TS, UK
Received 31 January 2003; accepted 16 May 2003
This paper is dedicated to Prof. Brain Johnson, in celebration of his 65th birthday
Abstract
Propargyl alcohols HCÅ
allylidene complexes [Ru2(CO)(m-CO){m-h1,h3-C(CR2OH)CHÄ
complexes 4aÁ
c with HBF4 removes the hydroxide group as water, giving the 2-butadienyl complexes [Ru2(CO)(m-CO)(m-h2,h3-
CR2ÄCCHÄCH2)(h-C5H5)2][BF4] (5a, RꢀH; 5b, RꢀMe; 5c, RꢀPh). The reactivity of 5aÁc towards nucleophiles and bases is
described. With hydride, 5aÁc undergo nucleophilic attack at the C(R2) carbon to give the allylidene complexes [Ru2(CO)(m-CO){m-
h1,h3-C(CR2H)CHÄ
CH2}(h-C5H5)2] (6a, RꢀH; 7, RꢀMe; 11, RꢀPh) and, in the case of 5c, the butadiene complex
[Ru2(CO)2(m-h2,h2-CPh2Ä CH2)(h-C5H5)2] (12) and the allene complex [Ru2(CO)2(m-h2,h2-CPh2Ä
CHCHÄ CÄCHMe)(h-C5H5)2]
(13), formally due to attack at the m-C and CH2 carbons, respectively. The complexes 5aÁc react with methyl lithium to undergo
nucleophilic attack predominantly at the C(R2) carbon, giving methylated allylidene complexes [Ru2(CO)(m-CO){m-h1,h3-
C(CR2Me)CHÄCH2}(h-C5H5)2] (6b, RꢀMe; 9, RꢀMe; 14, RꢀPh). With 5b and 5c methyl lithium also acts as a base,
abstracting protons to give the novel divinylcarbene complex [Ru2(CO)(m-CO){m-h1,h3-C(CMeÄ
CH2)CHÄCH2}(h-C5H5)2] (8) and
the m-butatriene complex [Ru2(CO)2(m-h2,h2-CPh2Ä
CÄCÄCH2)(h-C5H5)2] (15), respectively. Complexes 8 and 15 are formed
exclusively by treating 5b and 5c, respectively, with diazabicyclo[5.4.0]undec-7-ene (DBU). Complexes 8 and 9 were also prepared in
good yield by reaction of complex 2 with 2-methyl-1-buten-3-yne {CH2ÄC(Me)CÅCH} and t-butylacetylene, respectively.
Treatment of complex 8 with HBF4 resulted in protonation at each of the methylene groups, affording 5b and isomeric [Ru2(CO)(m-
/
CCR2OH (Rꢀ
/
H, Me or Ph) react with [Ru2(CO)(MeCN)(m-CO)(m-CH2)(h-C5H5)2] (2) to form the
/
CH2}(h-C5H5)2] (4a, RꢀH; 4b, RꢀMe; 4c, RꢀPh). Treatment of
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
/
CO){m-h2,h3-CH(Me)Ä
/
CC(Me)ÄCH2}(h-C5H5)2][BF4] (10). The structures of 5b, 5c and 8 were established by X-ray diffraction.
/
# 2003 Elsevier B.V. All rights reserved.
Keywords: Butadienyl ligands; Diruthenium cations; Propargyl alcohols; Crystal structures; X-ray diffraction
1. Introduction
h2,h3-2-butadienyl, the only reported examples of which
are C(R)CÄCH2}]
[Fe2(CO)5(m-PPh2){m-h2,h3-CH2Ä
(1a, Rꢀ Bu) [1], and no information is
Me; 1b, Rꢀt
available on their reactivity. In this paper we report a
substantial extension in the chemistry of the m-h2,h3-2-
butadienyl ligand, through the synthesis of cationic
diruthenium complexes and a study of their reactions
/
/
Over the past twenty years an extensive range of
complexes containing small organic ligands coordinated
at a dinuclear transition metal centre has been estab-
lished and the study of their chemistry has provided
valuable insights into catalysis by metal surfaces.
Typical species are C1 methyl and methylene, C2 vinyl
and vinylidene, C3 allenyl and allenylidene, and C4
butadiene. However, related complexes containing the
butadienyl ligand are rare. This is particularly so for m-
/
/
* Corresponding author. Tel.: ꢁ
929-0509.
E-mail address: selby.knox@bris.ac.uk (S.A.R. Knox).
/
44-117-928-7650; fax: ꢁ44-117-
/
0020-1693/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0020-1693(03)00391-8

30
J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á40
/
with nucleophiles and bases. This has led to a variety of
new m-allene, m-divinylcarbene, m-butadiene, and m-
butatriene species.
gave the m-allylidene complexes 4 within an hour at
room temperature, obtained after chromatography in
good yields (48-91%) as orange-red crystals. Identifica-
tion was straightforward, by comparison of analytical
and spectroscopic data (given in Tables 1 and 2 for all
new compounds) with those for known complexes of
2. Results and discussion
this type [3Á
/
6].
Proton NMR spectra confirm that regiospecific CÁ
/
C
The starting point for this work was the m-methylene
bond formation has occurred between the methylene
carbon and the unsubstituted carbon of the alkyne, in
that the three signals of a vinyl group are present with
characteristic double doublet cis, trans and geminal
couplings. Had the methylene linked with the substi-
tuted end of the alkyne the former alkyne proton would
be bound to the bridging carbon, giving a very different
coupling pattern. In addition, such a proton would have
complex
[Ru2(CO)(MeCN)(m-CO)(m-CH2)(h-C5H5)2]
(2) [2]. Previously, we have shown this to react with
mono-substituted alkynes to give m-allylidene complexes
[Ru2(CO)(m-CO)(m-h1,h3-CRCHÄ
/
CH2)(h-C5H5)2] (3),
carbon bond formation occurring via the least
carbonÁ
/
sterically hindered unsubstituted carbon of the alkyne
[3].
a characteristic [3Á
/
6] low field shift in the range d 9Á11
/
rather than the value of approximately d 5 observed.
The high field shift of one of the vinylic protons (ca. d
0.0) in complexes of this type has been attributed to their
being held in a region of shielding over the metalÁ
bond [3,6]. The OH protons of the complexes are
observed as singlets in the range d 2Á4.
The complexes 4aÁc exist as isomers deriving from cis
/
metal
/
It was therefore anticipated that reaction of 2 with
/
propargyl alcohols HCÅ
way form m-allylidene complexes [Ru2(CO)(m-CO){m-
h1,h3-C(CR2OH)CHÄ
CH2}(h-C5H5)2] (4) (see Scheme
/
CCR2OH would in the same
or trans arrangements of the cyclopentadienyl ligands, a
phenomenon commonly observed for diruthenium bis-
cyclopentadienyl complexes. Assignment of the isomers
was on the basis that the cis form is typically the most
abundant in such systems, for electronic reasons [7],
with the trans becoming more favoured sterically as the
substituent on the m-alkylidene carbon increases in size.
In accord, the cis form is dominant for 4a and 4b (ca.
20:1) while the trans is for 4c (ca. 25:1), though the latter
converts slowly to the cis isomer in solution at room
temperature; indeed, a solution of pure trans-4c gave
only cis-4c on slow crystallisation. Separation of the
isomers can be achieved by column chromatography,
when the trans isomers elute before the cis from
columns, as expected by the relative polarities of the
two forms.
/
1). In turn, treatment of the latter with HBF4 was
postulated to result in loss of water and formation of
cationic 2-butadienyl complexes [Ru2(CO)(m-CO)(m-
h2,h3-CR2Ä
/
CCHÄ
/
CH2)(h-C5H5)2][BF4]
(5).
This
proved to be the case.
2.1. Preparation of m-allylidene complexes
Reaction of complex 2 with a small excess of
propargyl alcohols HCÅCCR2OH (RꢀH, Me, Ph)
/
/
2.2. Synthesis of 2-butadienyl cations
Treatment of 4aÁ
OEt2 resulted in instantaneous precipitation of the 2-
butadienyl complexes [Ru2(CO)(m-CO)(m-h2,h3-CR2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5a, RꢀH; 5b, RꢀMe;
5c, RꢀPh) in high yield (83Á91%) as red or orangeÁred
/
c in tetrahydrofuran with HBF4×
/
/
/
/
/
/
/
/
crystals. Analytical and spectroscopic data are given in
Tables 1 and 2.
The IR spectra of complexes 5aÁc show a terminal
/
CO stretching band between 2008 and 2000 cmꢂ1, and
one between 1934 and 1908 cmꢂ1 suggestive of a semi-
bridging ligand, confirmed by X-ray diffraction studies
(see below). The proton NMR spectra have character-
istic signals for the vinylic protons of the butadienyl
Scheme 1. Synthesis of m-butadienyl complexes.

J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á
/40
31
Table 1
Analytical and physical data for new complexes
Complex
Colour
4a red
M. wt. a,b
C (%) a
H (%) a
[Ru2(CO)(m-CO){m-h1,h3-C(CH2OH)CHÄ
[Ru2(CO)(m-CO){m-h1,h3-C(CMe2OH)CHÄ
[Ru2(CO)(m-CO){m-h1,h3-C(CPh2OH)CHÄ
CH2}(h-C5H5)2]
[Ru2(CO)(m-CO)(m-h2,h3-CH2Ä
CCHÄCH2)(h-C5H5)2][BF4]
[Ru2(CO)(m-CO)(m-h2,h3-CMe2Ä
CCHÄCH2)(h-C5H5)2][BF4]
[Ru2(CO)(m-CO)(m-h2,h3-CPh2Ä
CCHÄCH2)(h-C5H5)2][BF4]
[Ru2(CO)(m-CO){m-h1,h3-C(Pri)CHÄ
CH2}(h-C5H5)2]
[Ru2(CO)(m-CO){m-h1,h3-C(CMeÄ
CH2)CHÄCH2}(h-C5H5)2]
[Ru2(CO)(m-CO){m-h1,h3-C(But)CHÄ
CH2}(h-C5H5)2]
[Ru2(CO)(m-CO)(m-h2,h3-CMeHÄ
CCMeÄCH2)(h-C5H5)2] [BF4]
[Ru2(CO)(m-CO){m-h1,h3-C(CPh2H)CCHÄ
CH2}(h-C5H5)2]
[Ru2(CO)2(m-h2,h2-CPh2Ä
CHCHÄCH2)(h-C5H5)2]
[Ru2(CO)2(m-h2,h2-CPh2Ä
CÄCHMe)(h-C5H5)2]
[Ru2(CO)(m-CO){m-h1,h3-C(CPh2Me)CHÄ
CH2}(h-C5H5)2]
/
CH2}(h-C5H5)2]
459(459) c
488(488)
42.19(41.92)
44.42(44.40)
54.75(55.08)
36.23(36.38)
39.04(38.86)
49.60(49.93)
46.22(45.95)
46.46(46.15)
46.66(47.10)
39.15(38.86)
56.49(56.56)
3.43(3.52)
4.13(4.14)
3.84(3.96)
2.84(2.86)
3.27(3.44)
3.45(3.40)
4.15(4.28)
3.77(3.87)
4.77(4.58)
3.42(3.44)
3.94(4.07)
/
CH2}(h-C5H5)2]
4b orange
4c orange
5a dark red
5b red/orange
5c red
/
584(612) c,d
442(529) c,e
470(557) c,e
595(682) c,e
471(471) c
470(470) c
486(486) c
470(557) e
596(596)
/
/
/
/
/
/
/
7
8
9
orange
orange/red
orange
/
/
/
/
/
10 orange
/
11 orange
/
/
12 orange
13 yellow/orange
14 orange
596(596)
596(596)
610(610)
57.05(56.56)
f
4.10(4.07)
f
/
/
f
f
/
a
b
c
d
e
f
Calculated values in parentheses.
EI mass spectrum unless otherwise stated.
FAB mass spectrum.
M
M
ꢁ ꢂ
/
CO.
ꢁ ꢂ
/BF4.
Satisfactory data not obtained, see Section 4.
ligands and, for 5a, the signals for the methylene
protons of the vinylidene unit, which have geminal
coupling of 5 Hz. The complexes 5a and 5b exist in
solution as cis and trans isomers, in approximately 13:1
and 3:1 ratios, respectively, but only the trans form is
plus an RuÁ
distances carbons C1Á
considered to comprise an h3Á
carbonÁcarbon distances within the group (1.40Á
A) are consistent with this, while for the h unit they are
typical of an alkene-type interaction. Thus, in 5b the
/
C s-bond, but on the basis of metalÁ
C2ÁC3 can equally well be
allyl group. The
1.42
/
carbon
/
/
/
/
/
2
˚
seen for 5c, a trend that parallels the situation for 4aÁ
/c.
˚
C4 is short at 1.378(10) A,
Confirmation of the structure of the cations and of the
assignment of isomers was achieved through X-ray
diffraction studies on complexes cis-5b and trans-5c.
carbonÁ
/
carbon distance C3Á
/
suggesting the low p-back donation expected for a
methyl-substituted alkene unit, while in 5c the corre-
˚
sponding distance is 1.406(3) A, reflecting the higher p-
back donation that results from introducing electron
withdrawing phenyl groups.
2.2.1. Molecular structures of cis-[Ru2(CO)(m-CO)(m-
h2,h3-CMe2Ä
/
CCHÄ
trans-[Ru2(CO)(m-CO)(m-h2,h3-CPh2Ä
CH2)(h-C5H5)2][BF4] (5c)
/
CH2)(h-C5H5)2][BF4] (5b) and
The major difference between the two structures is the
relative orientation of the cyclopentadienyl ligands, a cis
arrangement being observed in 5b and trans in 5c.
Comparison of Figs. 1 and 2 suggests that the change
from the electronically favoured [7] cis form in 5b to the
trans in 5c is sterically driven. Thus, in 5b the methyl
substituent C6 is close, but clearly acceptably so, to the
adjacent cyclopentadienyl ligand. However, in a cis
form of 5c there would be unacceptable clash between a
phenyl group in this position and the cyclopentadienyl
group, and as a result the trans isomer is favoured. It
can be seen from Fig. 2 that in the trans form there are
no significant interactions between the phenyl and
cyclopentadienyl groups.
/
CCHÄ
/
The structures of 5b and 5c, shown in Figs. 1 and 2,
respectively, are broadly similar; pertinent bond lengths
are given in Table 3. Each structure is based on a singly
metalÁmetal bonded diruthenium unit bridged asymme-
/
trically by a carbonyl ligand, with a second carbonyl
terminally bound to the ruthenium that is most weakly
bonded to the bridging CO. The semi-bridging carbonyl
˚
C7ꢀ2.317(6) A]
is slightly more bridging in 5b [Ru2Á
/
/
˚
C17ꢀ2.456(2) A], correlating with a
than in 5c [Ru2Á
/
/
˚
shorter RuÁRu bond length in 5b [2.7895(7) A] com-
/
˚
pared with 5c [2.8155(4) A]. The trans 2-butadienyl
ligands in each complex are near identical, being bonded
h2 to one metal and h3 to the other, with one carbon
effectively bridging the metalÁ
/
metal bond as a m-
2.2.2. Reactivity of [Ru2(CO)(m-CO)(m-h2,h3-CH2Ä
CH2)(h-C5H5)2][BF4] (5a)
Complex 5a reacts with lithium triethylborohydride
/
alkylidene. The ruthenium-carbon distances for this
bridging carbon are significantly shorter than those for
the other butadienyl carbons. The coordination of the
butadienyl can be represented in several ways. In
Scheme 1 it is shown as two h2-alkene interactions
CCHÄ
/
or methyl lithium to form the known allylidene com-
[Ru2(CO)(m-CO){m-h1,h3-C(R)CHÄ
plexes
C5H5)] (6a, Rꢀ
/
CH2}(h-
/
Me; 6b, Rꢀ
/
Et) in approximately 70%

Table 2
IR, 1H and 13CÁ
/
{1H} NMR data for new complexes
a
Complex n(CO) (cmꢂ1
)
1H NMR (d) b
13CÁ{1H} NMR (d) b
/
4a
1947(s), 1780(m)
5.27 (s, 5H, h-C5H5), 5.00 (m, 2H), 4.93 (s, 5H, h-C5H5), 4.58 (dd, J 7, J 9, 1H), 241.6 (m-CO), 203.3 (CO), 177.4 (m-C), 88.4, 83.7 (h-C5H5), 80.4 (CH), 78.4
2.65 (dd, J 7, J 3, 1H), 1.94 (s, 1H), 0.02 (dd, J 9, J 7, 1H); {5.31 (s, h-C5H5), (CH2OH), 40.9 (CH2); {203.8 (CO), 174.9 (m-C), 88.5, 84.0 (h-C5H5), 79.0 (CH),
4.94 (s, h-C5H5)} c
85.6 (CH2OH), 40.6 (CH2)} c
4b
1948(s), 1774(s)
5.33 (s, 5H, h-C5H5), 4.99 (s, 5H, h-C5H5), 4.51 (dd, J 7, J 9, 1H), 2.71 (dd, J 7, 243.0 (m-CO), 203.7 (CO), 190.0 (m-C), 89.2 (h-C5H5), 83.5 (h-C5H5), 78.7
J 3, 1H), 2.09 (s, 1H), 1.63, 1.62 (s, 6H, 2Me), 0.01 (dd, J 9, J 7, 1H); {5.09 (s, (CMe2OH), 77.6 (CH), 43.0 (CH2), 35.2, 31.4 (Me) d
5H, h-C5H5), 5.00 (s, 5H, h-C5H5), 4.24 (dd, J 7, J 9, 1H), 2.62 (dd, Jꢀ7, J 3,
/
1H), 2.24 (s, 3H, Me), 1.61 (s, 4H, Me and OH), -0.08 (dd, J 9, J 7, 1H)}
7.5 (m, Ph), 4.67 (dd, J 7, J 9), 4.64 (s, 5H, h-C5H5), 4.59 (s, 5H, h-C5H5), 4.10 236.8 (m-CO), 197.2 (CO), 182.5 (m-C), 150.4, 145.7 (ipso-Ph), 128.3, 127.9, 127.3,
4c
1946(s), 1781(s);
{1951(s), 1776(m)} (s, 1H), 2.70 (dd, J 7, J 1, 1H), 0.20 (dd, J 9, J 1, 1H) e; {7.5 (m, 10H, Ph), 3.98 126.8, 126.7 (Ph), 89.3 (h-C5H5), 86.2 (CPh2OH), 86.0 (h-C5H5), 82.0 (CH), 39.2
(dd, J 7, J 9, 1H), 5.05, 4.93 (s, 10H, h-C5H5), 3.47 (s, 1H), 2.53 (dd, J 7, J 3, (CH2) e; {240.6 (m-CO), 205.2 (CO), 187.7 (m-C), 151.3, 147.2 (ipso-Ph), 127.9,
1H), 0.33 (dd, J 9, J 3, 1H)}e
127.6, 127.4, 126.6, 126.0 (Ph), 90.2 (h-C5H5), 86.8 (CPh2OH), 84.4 (h-C5H5), 83.4
(CH), 42.0 (CH2)} e
5a
5b
2008(s), 1934(m,br) 5.67 (ddt, J 7, J 10, J 1, 1H), 5.41 (s, 5H, h-C5H5), 5.32 (s, 5H, h-C5H5), 4.64 (d, 209.4 (semi-bridging-CO), 199.8 (CO), 192.1 (m-C), 90.6, 89.8 (h-C5H5), 70.5 (CH),
J 5, 1H), 4.28 (dd, J 5, J 1, 1H), 3.81 (ddd, J 7, J 1, J 1, 1H), 1.66 (ddd, J 10, J 48.6 (CH2), 31.4 (CH2) c,f
1, J 1, 1H) f; {5.42 (s, 5H, h-C5H5), 4.67 (d, J 4, 1H), 1.55 (dd, J 9, J 2, 1H)} c,f
2000(s), 1908(m)
5.50 (s, h-C5H5), 5.38 (dd, J 7, J 10, 1H), 5.25 (s, h-C5H5), 3.67 (dd, J 7, J 2, H), 212.0 (semi-bridging-CO), 199.6 (CO), 190.5 (m-C), 92.4, 89.3 (h-C5H5), 80.5
2.48 (s, 3H, Me), 2.14 (s, 3H, Me), 1.53 (dd, J 10, J 2, 1H) f; {5.53 (s, h-C5H5), (CMe2), 68.5 (CH), 48.1 (CH2), 35.6, 33.7 (Me) f; {196.6 (CO), 194.0 (m-C), 93.5,
5.25 (s, h-C5H5), 3.67 (dd, J 7, J 3, H), 2.56 (s, 3H, Me), 2.25 (s, 3H, Me), 1.45 88.4 (h-C5H5), 86.9 (CMe2), 47.6 (CH2), 36.4, 34.0 (Me)} c,f
(dd, J 9, J 3, 1H)} c,f
5c
7
2006(s), 1927(m/br) 7.86 (m, 10H, Ph), 6.20 (dd, J 7, J 10, 1H), 5.27 (s, 5H, h-C5H5), 5.05 (s, 5H, h- 209.5 (semi-bridging-CO), 197.8 (CO), 190.0 (m-C), 146.3, 144.9 (ipso-Ph), 134.8,
C5H5), 4.12 (dd, J 7, J 2, 1H), 1.94 (dd, J 10, J 2, 1H) f
130.2, 129.5, 128.9, 128.6, 128.5 (Ph), 94.1, 90.9 (h-C5H5), 80.8 (CPh2), 75.1 (CH),
48.5 (CH2) f
1942(s), 1769(s);
{1937(s), 1772(s)}
5.22 (s, 5H, h-C5H5), 4.93 (s, 5H, h-C5H5), 4.37 (dd, J 9, J 7, 1H), 3.70 (sept, J 244.7 (m-CO), 204.2 (CO), 191.5 (m-C), 89.5, 83.8 (h-C5H5), 72.3 (CH), 40.6
7, 1H), 2.64 (dd, J 7, J 2, 1H), 1.47 (d, J 7, 3H, Me), 1.36 (d, J 7, 3H, Me), ꢂ (CHMe2), 31.6 (CH2), 29.7, 23.6 (Me) ;{241.2 (m-CO), 198.4 (CO), 186.0 (m-C),
/
0.17 (dd, J 9, J 2, 1H); {5.01 (s, 5H, h-C5H5), 4.91 (s, 5H, h-C5H5), 4.64 (dd, J 88.5, 85.2 (h-C5H5), 78.9 (CH), 48.4 (CHMe2), 38.4 (CH2), 28.2, 26.7 (Me)}
9, J 7, 1H), 3.40 (sept, J 7, 1H), 2.55 (dd, J 7, J 1, 1H), 1.46 (d, J 7, 3H, Me),
1.39 (d, J 7, 3H, Me), 0.11 (dd, J 9, J 1, 1H)}
8
9
1946(s), 1772(s);
{1939(s), 1775(s)}
5.09 (s, 5H, h-C5H5), 4.99 (s, 5H, h-C5H5), 4.83 (br, 2H), 4.23 (dd, J 7, J 9, 1H), 243.4 (m-CO), 203.6 (CO), 183.5 (m-C), 160.0 (CMe), 107.3 (CH2), 90.5, 84.3 (h-
2.61 (d, J 7, J 3, 1H), 2.20 (t, J 1, 3H, Me), ꢂ
0.08 (dd, J 9, J 3, 1H); {4.90 (s, C5H5), 78.3 (CH), 39.0 (CH2), 27.6 (Me) d
/
5H, h-C5H5), 4.89 (s, 5H, h-C5H5), 4.80 (br, 2H), 4.72 (dd, J 7, J 9, 1H), 2.62 (d,
J 7, J 2, 1H), 2.31 (br, 3H, Me), 0.14 (dd, J 9, J 2, 1H)}
1942(s), 1766(s);
{1935(s), 1771(s)}
5.26 (s, 5H, h-C5H5), 4.94 (s, 5H, h-C5H5), 4.41 (dd, J 7, J 9, 1H), 2.65 (dd, J 7, 244.8 (m-CO), 204.5 (CO), 195.7 (m-C), 89.1, 83.3 (h-C5H5), 74.9 (CH), 44.9
J 3, 1H), 1.43 (s, 9H, 3Me), ꢂ
/
0.12 (dd, J 9, J 3, 1H); {5.02 (s, 5H, h-C5H5), (CMe3), 42.6 (CH2), 35.5 (3ꢃ
Me) d
/
4.96 (s, 5H, h-C5H5), 4.65 (pseudo-t, J 8, 1H), 2.60 (d, J 8, 1H), 1.49 (s, 9H,
3Me), 0.07 (dd, J 9, J 3, 1H)}
10
11
2005(s), 1904(m)
5.72 (q, J 7, 1H) 5.49 (s, 5H, h-C5H5), 5.31 (s, 5H, h-C5H5), 3.71 (d, J 2, 1H), 212.2 (m-CO), 198.9 (CO), 190.7 (m-C), 91.7, 90.1 (h-C5H5), 80.4 (CMe), 68.5
2.35 (d, J 7, 3H), 2.25 (s, 3H, Me), 1.50 (d, J 2, 1H) f CHCH2) f,g
(CH), 50.9 (Me), 48.9 (CH2), 25.8 (Ä
7.29 (m, Ph), 6.33 (s, 1H), 4.99 (s, 5H, h-C5H5), 4.76 (s, 5H, h-C5H5), 4.17 (dd, J 241.9 (m-CO), 205.0 (CO), 180.9 (m-C), 148.9, 146.9 (ipso Ph), 131.0, 130.4, 130.4,
7, J 8, 1H), 2.56 (m, H), ꢂ
0.07 (dd, J 8, J 2, 1H)e; {7.30 (m, Ph), 6.29 (s, 1H), 128.4, 127.6, 127.4, 126.6, 126.0, 125.8, 125.8 (Ph), 90.1, 84.6 (h-C5H5), 78.2 (CH),
4.83 (dd, J 7, J 9, 1H), 4.60 (s, 5H, h-C5H5), 4.52 (s, 5H, h-C5H5), 2.56 (m, H), 73.8 (CPh2H), 40.5 (CH2) e; {239.3 (m-CO), 198.2 (CO), 175.3 (m-C), 148.5, 144.6
/
1947(s), 1771(s);
{1937(s), 1774(s)}
/
0.12 (dd, J 9, J 1, 1H)} e
(ipso Ph), 130.4, 129.9, 129.4, 128.6, 128.4, 128.2, 128.0, 126.7, 126.6, 126.4 (Ph),
90.1, 85.5 (h-C5H5), 79.9 (CH), 74.3 (CPh2H), 37.7 (CH2)} e
7.12 (m, 10H), 5.04, 4.76 (s, 10H, h-C5H5), 2.71 (d, J 7, 1H), 2.54 (d, J 10, 1H), 206.1 (CO), 206.0 (CO), 151.2, 145.8 (ipso Ph), 135.1, 128.2, 127.8, 126.1, 126.0,
2.20 (m, 1H), 1.99 (d, J 10, 1H) e 124.4 (Ph), 88.4, 85.5 (h-C5H5), 51.7 (CH), 49.1 (CH), 24.4 (CPh2), 23.1 (CH2) e
12
1904

Table 2 (Continued)
a
Complex n(CO) (cmꢂ1
)
1H NMR (d) b
13CÁ{1H} NMR (d) b
/
13
14
1934(s), 1914(s)
1946(s), 1774(s)
7.16 (m, 10H), 4.93 (q, J 6, 1H), 4.73 (s, 5H, h-C5H5), 4.48 (s, 5H, h-C5H5), 2.26 207.9 (CO), 207.7 (CO), 193.2 (m-C), 154.3, 148.8 (ipso Ph), 134.6, 127.9, 127.0,
(d, J 6, 3H) e 126.4, 126.0, 123.7 (Ph), 87.9 (h-C5H5), 61.6 (CPh2), 44.2 (CH3), 14.3 (CH) e
7.30 (m, Ph), 4.73 (s, 5H, h-C5H5), 4.60 (s, 5H, h-C5H5), 4.40 (dd, J 7, J 9, 1H), 239.6 (m-CO), 206.6 (CO), 198.8 (m-C), 150.3, 149.2 (ipso Ph), 130.5-125.5 (Ph),
2.57 (s, 3H), 0.15 (dd, J 9, J 1, 1H) c,e; {7.30 (m, Ph), 5.02 (s, 5H, h-C5H5), 4.88 90.0, 85.9 (h-C5H5), 83.0 (CH), 60.5 (CPh2Me), 38.1 (CH2), 35.6 (Me) e,h; {242.1
(s, 5H, h-C5H5), 3.60 (dd, J 7, J 8, 1H), 2.42 (dd, J 7, J 3, 1H), 2.53 (s, 3H), ꢂ
/
(m-CO), 206.2 (CO), 184.5 (m-C), 152.2, 150.4 (ipso Ph), 130.5-125.5 (Ph), 88.2, 85.1
(h-C5H5), 85.3 (CH), 60.9 (CPh2Me), 40.9 (CH2), 34.5 (Me)} e,h
0.12 (dd, J 8, J 3, 1H)} e
a
b
c
In dichloromethane; data for minor isomer in parentheses.
In CDCl3 unless otherwise stated; coupling constants J in Hz; data for minor isomer in parentheses.
Other peak(s) obscured.
Minor isomer not seen.
In CD2Cl2.
d
e
f
CD3NO2.
g
h
Recorded at ꢂ/20 8C.
Isomers inseparable, phenyl carbons not attributable.

34
J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á40
/
Table 3
Selected bond lengths (A) for complexes 5b, 5c and 8
˚
5b
5c
8
Ru1Á
Ru1Á
Ru1Á
Ru1Á
Ru1Á
Ru1Á
Ru2Á
Ru2Á
Ru2Á
Ru2Á
C1Á
C2Á
C3Á
C4Á
C4Á
C4Á
/
Ru2
C1
2.7895(7)
2.205(7)
2.177(7)
2.054(7)
1.920(7)
2.8155(4)
2.215(3)
2.188(2)
2.092(2)
2.7210(8)
2.173(8)
2.148(7)
2.133(5)
1.953(6)
/
/
C2
/
C3
/
C7
/
C17
C3
1.909(3)
2.082(2)
2.332(2)
/
2.097(6)
2.343(7)
2.317(7)
2.078(5)
2.093(6)
/
C4
/
C7
/
C17
2.456(2)
1.407(4)
1.406(3)
1.406(3)
1.518(3)
/
C2
C3
C4
C5
C6
C11
1.409(10)
1.422(9)
1.403(11)
1.425(10)
1.490(10)
1.433(11)
1.377(14)
/
/
1.378(10)
1.502(12)
1.510(11)
/
/
/
1.503(3)
Scheme 2. Reactions of 5b and alternative synthesis of products from
2.
Reaction of 5a with either the sterically hindered base
1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) or potassium
t-butoxide gave no identifiable products.
Scheme 2. In each case carbonÁcarbon bond formation
/
occurs between the methylene ligand and the less
hindered, unsubstituted carbon of the alkyne unit, as
expected.
2.2.3. Reactivity of [Ru2(CO)(m-CO)(m-h2,h3-CMe2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5b)
Complex 5b reacts with lithium triethylborohydride to
/
/
2.2.4. Molecular structure of cis-[Ru2(CO)(m-CO){m-
CH2}(h-C5H5)2] (8)
h1,h3-C(CMeÄ
/
CH2)CHÄ
/
give the new allylidene complex [Ru2(CO)(m-CO){m-
h1,h3-C(iPr)CHÄ
CH2}(h-C5H5)2] (7) in 71% yield as
/
The structure of 8 is shown in Fig. 3 and selected
bond lengths are given in Table 3. The complex can be
considered as a novel m-divinylcarbene species with one
of the vinyl substituents coordinated. Compared with
5b, from which 8 is derived by deprotonation, significant
separable cis and trans isomers (1:1 ratio). It is likely, by
analogy with 5a, that hydride attack occurs directly at
the C4 carbon. Treatment of 5b with methyl lithium
gives the allylidene complex [Ru2(CO)(m-CO){m-h1,h3-
C(tBu)CHÄ
CH2}(h-C5H5)2] (9) similarly, but in only
/
shortening of the RuÁRu bond has occurred, from
/
˚
˚
2.7895(7) A in cationic 5b to 2.7210(8) A in neutral 8.
The diruthenium unit is also close to being symmetri-
cally bridged by a carbonyl and has a cis arrangement of
cyclopentadienyl ligands. The unsubstituted vinyl group
15% yield. The dominant reaction pathway for this
reagent is for it to act as a base, abstracting a proton
from a methyl group of the butadienyl ligand to give the
new divinylcarbene complex [Ru2(CO)(m-CO){m-h1,h3-
is coordinated to Ru1 with a near identical C1ÁC2 bond
/
C(CMeÄ
/
CH2)CHÄCH2}(h-C5H5)2] (8) in 43% yield. As
/
˚
length [1.403(11) A] compared with that in the parent
expected, treatment of 5b with DBU also gave 8, in 45%
yield (see Scheme 2). Both 8 and 9 exist as cis and trans
isomers, in 5:1 and 8:1 ratios, respectively, separable by
chromatography. The assignment of the isomers was
firmly established by an X-ray diffraction study on cis-
8. Spectroscopic and other data are given in Tables 1
and 2.
˚
compound 5b [1.409(10) A], while the methyl-substi-
tuted vinyl group has an uncoordinated C3ÁC6 distance
/
˚
of 1.377(14) A.
2.2.5. Protonation of [Ru2(CO)(m-CO){m-h1,h3-
C(CMeÄCH2)CHÄCH2}(h-C5H5)2] (8)
/
/
Complexes 8 and 9 can be obtained in good yield (63
and 58%) by reaction of complex 2 with t-butylacetylene
or 2-methyl-1-buten-3-yne respectively, as shown in
The deprotonation of 5b is partially reversible. Thus,
addition of HBF4 to a tetrahydrofuran solution of 8
gave some 5b but the main product (3:1 ratio) was the

J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á
/40
35
Scheme 3. Protonation of 8.
Fig. 3. Molecular structure of 8. Cyclopentadienyl hydrogens have
been omitted for clarity.
new 2-butadienyl cation [Ru2(CO)(m-CO)(m-h2,h3-
CH(Me)Ä
/
CC(Me)ÄCH2)(h-C5H5)2][BF4] (10). The pro-
/
ducts were obtained in 74% combined yield and could
not be separated, but 10 was readily identified from its
1H and 13C NMR spectra. The complex results from
protonation at the methylene group of the coordinated
vinyl, releasing this carbon from coordination and
provoking rearrangements to maintain 18-electron con-
figurations for the metal atoms, i.e. the other vinyl
group is brought into coordination and the two
carbonyls switch their terminal and bridging bonding
modes (Scheme 3).
2.2.6. Reactivity of [Ru2(CO)(m-CO)(m-h2,h3-CPh2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5c)
/
/
Like 5a and 5b, 5c undergoes nucleophilic attack at
the C4 carbon on treatment with lithium triethylbor-
ohydride, to give the m-allylidene complex [Ru2(CO)(m-
CO){m-h1,h3-C(CPh2H)CHÄ
CH2}(h-C5H5)2] (11), iso-
/
Scheme 4. Reaction of 5c with hydride.
lated in 68% yield as a 1:1 mixture of cis and trans
isomers. But unlike 5a and 5b, hydride attack on 5c also
redirection of attack from C4 being attributable to the
steric crowding arising from the two phenyl substitu-
tents.
gives a m-butadiene complex [Ru2(CO)2(m-h2,h2-CPh2Ä
/
CHCHÄ
/
CH2)(h-C5H5)2] (12) in 23% yield and a m-
allene complex [Ru2(CO)2(m-h2,h2-CPh2Ä
/
CÄCHMe)(h-
/
Methyl lithium also reacts with 5c by nucleophilic
addition at C4, to form the m-allylidene complex
C5H5)2] (13) in 8% yield (see Scheme 4). Diruthenium
complexes of type 12 have been reported [10] and the m-
[Ru2(CO)(m-CO){m-h1,h3-C(CPh2Me)CHÄ
CH2}(h-
/
CPh2Ä
pared in this laboratory by a different route (hydro-
genation of a m-CÄCÄCPh2 allenylidene ligand) and its
/
CÄ
/
CH2 analogue of 13 has recently been pre-
C5H5)2] (14) in 22% yield as an inseparable 2:1 mixture
of cis and trans isomers. However, the major reaction
pathway is proton abstraction from C2, giving the m-
/
/
structure established by X-ray diffraction [11]. Spectro-
scopic characterisation of 12 and 13 was therefore
straightforward (Tables 1 and 2), although the low yield
of the latter prevented analytical data being obtained.
The formation of 12 and 13 corresponds to hydride
attack at the C3 and C1 carbons of 5c, respectively, the
butatriene complex [Ru2(CO)2(m-h2,h2-CPh2 Ä
/
CÄ
/
CÄ
/
CH2)(h-C5H5)2] (15) in 52% yield (see Scheme 5).
Complex 15 has recently been prepared in this labora-
tory by another route, the combination of a m-CÄ
CPh2 allenylidene ligand with diazomethane, and its
/
CÄ
/

36
J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á40
/
structure has been established by X-ray diffraction [11].
It was therefore readily identified spectroscopically.
Abstraction of the C2 proton of 5c by treatment with
DBU in dichloromethane gives 15 cleanly, in 63% yield.
Autospec instrument. Proton and 13C NMR spectra
were recorded on JEOL D 270, GX 400 and Lambda
300 spectrometers operated in Fourier Transform mode,
with field maintained by an external lock system.
Elemental analyses were performed by the Microanaly-
tical Laboratory of the School of Chemistry, University
of Bristol.
3. Conclusions
[Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2] [12] and [Ru2-
(CO)(MeCN)(m-CO)(m-CH2)(h-C5H5)2] (2) [2] were pre-
The reactions of the m-C4R2Ä
/
C3C2HÄ
/
C1H2 cations
pared using literature methods. Tetrafluoroboric acidÁ
/
5aÁc with LiBHEt3 and MeLi are clearly strongly
/
diethyl ether complex, lithium triethylborohydride, 2-
propyn-1-ol, 2-methyl-3-butyn-2-ol, diphenyl-2-propyn-
1-ol, t-butylacetylene, 2-methyl-1-buten-3-yne, lithium
triethylborodeuteride, methyl lithium and Celite (Al-
drich) were used as supplied.
influenced by steric effects. When these are small
nucleophilic addition is favoured at C4, to give a m-
allylidene complex. Thus, hydride addition occurs
exclusively at this carbon for 5a and 5b (Rꢀ
/H or
Me), but for more crowded 5c (Rꢀ
/
Ph) approximately
one third of the addition is deflected to C1 and C3,
generating m-allene and m-butadiene complexes. With
4.1. Preparation of [Ru2(CO)(m-CO){m-h1,h3-
MeLi the pattern is similar. For 5a (RꢀH) there is
/
C(CH2OH)CHÄ
/
CH2}(h-C5H5)2] (4a)
exclusive addition of Meꢂ to C4 but for the substituted
species 5b and 5c addition to this carbon is a minor
pathway. However, instead of addition to the less
electrophilic carbons C1Á3, Meꢂ acts predominantly
(ca. 3:1 ratio) as a base, abstracting a proton from a
methyl group on C4 (5b) or from C2 (5c).
An acetonitrile (120 cm3) solution of [Ru2(CO)-
(MeCN)(m-CO)(m-CH2)(h-C5H5)2] (2) was prepared
from [Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2] (512 mg,
1.19 mmol). Dichloromethane (120 cm3) was added,
followed by a slight excess of 2-propyn-1-ol (0.10 cm3,
1.7 mmol). The orange solution turned red over 1 h.
Removal of the solvent and chromatography of the
residue gave three bands. The first (yellow) eluted with
4. Experimental
dichloromethaneꢁhexane (2:3) and was shown by IR
/
Reactions and general manipulations were performed
under a nitrogen atmosphere using dried, deoxygenated
solvents. Photolysis reactions were carried out in silica
glass tubes held approximately 20 cm from a 500 W
mercury vapour lamp as a source of UV radiation.
Column chromatography was performed on alumina
(Brockmann activity II). IR spectroscopy was with a
spectroscopy to contain 20 mg of [Ru2(CO)2(m-CO)(m-
CH2)(h-C5H5)2]. The second (yellow) eluted with
dichloromethaneꢁhexane (65:35) and gave 165 mg
/
(30%) of cis- and trans-4a as an orange residue. The
third band (pale orange) eluted with dichloromethane
and gave 95 mg (18%) of cis-4a as an orange residue.
Red crystals of cis-4a were grown by layering a
saturated dichloromethane solution with hexane.
PerkinÁElmer 1710 Fourier transform spectrometer
/
using calcium fluoride cells of 1 mm path length. EI
and FAB mass spectra were recorded using a Fisons
4.2. Preparation of [Ru2(CO)(m-CO){m-h1,h3-
C(CMe2OH)CHÄ
/
CH2}(h-C5H5)2] (4b)
An acetonitrile (200 cm3) solution 2 was prepared
from [Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2] (499 mg, 1.16
mmol). The solvent volume was reduced under reduced
pressure to approximately 50 cm3 then dichloromethane
(100 cm3) was added, followed by a slight excess of 2-
methyl-3-butyn-2-ol (0.14 cm3, 1.4 mmol). The orange
solution turned red over 1 h. Removal of the solvent and
chromatography of the residue gave three bands. The
first (orange) was eluted with dichloromethaneꢁhexane
/
(1:3) and gave 12 mg (2%) of trans-4b as an orange
residue. The second (pale orange) eluted with
dichloromethaneꢁhexane (2:3) and gave 70 mg of
/
impure [Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2]. The third
(pale orange) eluted with dichloromethane/hexane
(45:55) and gave 307 mg (54%) of cis-4b, obtained as
Scheme 5. Reactions of 5c.

J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á
/40
37
orange crystals by slow evaporation of a chloroform
solution.
4.6. Preparation of [Ru2(CO)(m-CO)(m-h2,h3-CPh2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5c)
/
/
Tetrafluoroboric acid (0.45 cm3, 2.36 mmol) was
added to a thf (30 cm3) solution of 4c (0.485 mg, 0.79
mmol). An orange precipitate began to form immedi-
ately and after 0.25 h diethyl ether (60 cm3) was added
and the supernatant solution was removed with a
syringe. The orange precipitate was washed with diethyl
4.3. Preparation of [Ru2(CO)(m-CO){m-h1,h3-
C(CPh2OH)CHÄ
/
CH2}(h-C5H5)2] (4c)
An acetonitrile (120 cm3) solution of 2 was prepared
from [Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2] (520 mg, 1.20
mmol). Dichloromethane (100 cm3) was added, followed
by a slight excess of 1,1-diphenyl-2-propyn-1-ol (280 mg,
1.35 mmol). The solution was stirred for 1 h. Removal
of the solvent and chromatography of the residue gave
ether (2ꢃ
20 cm3) and then dried under reduced
/
pressure, giving 452 mg (83%) of 5c. Red crystals were
grown by layering a nitromethane solution with diethyl
ether.
two bands. The first eluted with dichloromethaneꢁ
hexane (3:7) and gave approximately 5 mg of 2. The
second (orange) eluted with dichloromethaneꢁhexane
(2:3) and gave 670 mg (91%) of cis- and trans-4c as an
orange powder. Separation of the isomers was achieved
through a second chromatography, 356 mg of cis- and
trans-4c giving two orange bands. The first, eluted with
/
/
4.7. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CH2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5a) with lithium
triethylborohydride
/
/
Lithium triethylborohydride (0.1 cm3 of 1 M thf
solution, 0.1 mmol) was added to a dichloromethane (25
cm3) solution of 5a (50 mg, 0.095 mmol). The solution
was stirred for 0.5 h then two drops of water were added
and the mixture was filtered through Celite. After
evaporation to dryness the orange residue was recrys-
tallised from dichloromethane layered with hexane to
give 30 mg (70%) of red crystalline [Ru2(CO)(m-CO)(m-
dichloromethaneꢁ
/
hexane (1:3), gave 240 mg of trans-
4c, while the second, eluted with dichloromethaneꢁ
/
hexane (1:1), gave 13 mg of cis-4c. Attempts to crystal-
lise trans-4c by the slow evaporation of a dichloro-
methane solution gave orange crystals of cis-4c.
h1,h3-CMeCHÄ
IR and NMR spectroscopy.
/
CH2)(h-C5H5)2] (6a) [8], identified by
4.4. Preparation of [Ru2(CO)(m-CO)(m-h2,h3-CH2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5a)
/
/
Tetrafluoroboric acid (0.2 cm3, 1.05 mmol) was added
to a thf (20 cm3) solution of 4a (240 mg, 0.52 mmol). An
orange precipitate began to form immediately. After
0.25 h diethyl ether (30 cm3) was added to complete
precipitation and the supernatant solution was removed
with a syringe. The orange precipitate was washed with
4.8. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CH2Ä
CH2)(h-C5H5)2][BF4] (5a) with lithium
triethylborodeuteride
/
CCHÄ
/
In an identical manner to that described above, 5a (60
mg, 0.11 mmol) was treated with lithium triethylbor-
odeuteride (0.14 cm3 of 1 M thf solution, 0.14 mmol) to
give 50 mg (98%) of [Ru2(CO)(m-CO){m-h1,h3-
diethyl ether (2ꢃ
20 cm3) and dried in vacuo, giving 250
/
mg (91%) of 5a. Recrystallisation was achieved by
layering a saturated nitromethane solution with diethyl
ether, giving dark red crystals.
C(CH2D)CHÄ
CH2}(h-C5H5)2] (d1-6a).
/
4.5. Preparation of [Ru2(CO)(m-CO)(m-h2,h3-CMe2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5b)
/
4.9. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CH2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5a) with methyl lithium
/
/
/
Tetrafluoroboric acid (0.14 cm3, 0.73 mmol) was
added to a thf (10 cm3) solution of 4b (300 mg, 0.61
mmol). An orange precipitate began to form immedi-
ately. After 0.25 h, diethyl ether (20 cm3) was added to
complete precipitation and the supernatant solution was
removed with a syringe. The orange precipitate was
A large excess of methyl lithium (0.47 cm3 of 1.6 M
diethyl ether solution, 0.752 mmol) was added to a
dichloromethane (25 cm3) solution of 5a (50 mg, 0.095
mmol). The solution was stirred for 0.5 h then iso-
propanol (2 cm3) was added, the mixture passed through
Celite and the solvent removed. The resultant orange
residue was dried under reduced pressure overnight to
washed with diethyl ether (2ꢃ
20 cm3) and then dried
/
under reduced pressure to give 310 mg (90%) of 5b. Red/
orange crystals were grown by layering a nitromethane
solution with diethyl ether.
give 30 mg (69%) of [Ru2(CO)(m-CO)(m-h1,h3-CEtCHÄ
/
CH2)(h-C5H5)2] (6b) [9], identified by IR and NMR
spectroscopy.

38
J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á40
/
4.10. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CMe2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5b) with lithium
triethylborohydride
/
4.13. Preparation of 9 from [Ru2(CO)(MeCN)(m-
CO)(m-CH2)(h-C5H5)2] (2)
/
An acetonitrile solution of 2 was prepared from
[Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2] (0.480 g; 1.11
mmol). The solvent volume was reduced to approxi-
mately 60 cm3 and dichloromethane (90 cm3) added. A
slight excess of t-butylacetylene (0.15 cm3; 1.19 mmol)
was then added and the solution stirred for 1 h.
Removal of the solvent and chromatography gave two
Lithium triethylborohydride (0.246 cm3 of 1 M thf
solution, 0.246 mmol) was added to a dichloromethane
(50 cm3) solution of 5b (130 mg, 0.23 mmol). The
solution was stirred for 10 min then the solvent was
removed leaving an orange residue. Chromatography
gave two bands. The first (orange) eluted with
dichloromethaneꢁ
trans-[Ru2(CO)(m-CO){m-h1,h3-C(CHMe2)CHÄ
CH2}(h-C5H5)2] (7) as an orange powder. The second
(orange/yellow) eluted with dichloromethaneꢁhexane
(2:3) to give 40 mg (36%) of cis-7 as an orangeÁyellow
/
hexane (1:4) to give 39 mg (35%) of
bands. The first (orange) eluted with dichloromethaneꢁ
hexane (1:4) and gave 40 mg (7%) of trans-9 as an
orange residue. The second band (orange) eluted with
/
/
/
dichloromethaneꢁhexane (3:7) and gave 300 mg (56%)
/
/
of cis-9, from which orange crystals were grown by
allowing a saturated dichloromethane solution to diffuse
into hexane at low temperature (0 8C).
residue. Orange crystals of cis-7 were grown by layering
a saturated dichloromethane solution with hexane.
4.14. Reaction of 5b with 1,8-diazobicyclo[5.4.0]undec-
7-ene (DBU)
4.11. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CMe2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5b) with methyl lithium
/
/
DBU (0.40 cm3, 0.27 mmol) was added to an orange
dichloromethane (10 cm3) solution of 5b (0.04 g, 0.07
mmol). The solution was stirred for 10 min and the
solvent was then removed. The resultant orange residue
was crystallised by layering a saturated dichloromethane
An excess of methyl lithium (0.4 cm3 of 1.6 M diethyl
ether solution, 0.64 mmol) was added to a dichloro-
methane (80 cm3) solution of 5b (154 mg, 0.28 mmol).
The solution was stirred for 1 h then solvent was
removed. Chromatography of the orange residue gave
three bands. The first (pale orange) eluted with
solution with hexane, giving 15 mg (45%) of orangeÁred
/
8.
dichloromethaneꢁ
1 mg of unidentified product(s). The second band
(orange) eluted with dichloromethaneꢁhexane (2:3)
and gave 20 mg (15%) of [Ru2(CO)(m-CO)(m-h1,h3-
CButCHÄ
CH2)(h-C5H5)2] (9) as an orange powder. The
third band (orange) eluted with dichloromethaneꢁ
hexane (1:1) to give 56 mg (43%) of [Ru2(CO)(m-
/hexane 1:5 and gave approximately
4.15. Reaction of 8 with tetrafluoroboric acid
/
Tetrafluoroboric acid (0. 11 cm3, 0.799 mmol) was
added to an orange thf (10 cm3) solution of 8 (100 mg,
0.212 mmol). An orange precipitate began to form and
diethyl ether (20 cm3) was added to complete precipita-
tion. The supernatant solution was removed and the
orange residue washed with diethyl ether (20 cm3) and
dried under reduced pressure. The resulting orange
powder (87 mg, 74%) contained [Ru2(CO)(m-CO){m-
/
/
CO){m-h1,h3-C(CMeÄ
/
CH2)CHÄCH2}(h-C5H5)2] (8),
/
obtained as orange/red crystals by layering a saturated
dichloromethane solution with hexane.
4.12. Preparation of 8 from [Ru2(CO)(MeCN)(m-
CO)(m-CH2)(h-C5H5)2] (2)
h2,h3-CH(Me)Ä
/
CC(Me)Ä
/
CH2}(h-C5H5)2][BF4]
(10)
and cis- and trans-5b in a 10:2:1 ratio by NMR
spectroscopy.
An acetonitrile solution of 2 was prepared from
[Ru2(CO)2(m-CO)(m-CH2)(h-C5H5)2] (0.480 g, 1.11
mmol). The solvent volume was reduced to approxi-
mately 60 cm3 and dichloromethane (80 cm3) added. A
slight excess of 2-methyl-1-buten-3-yne (0.12 cm3, 1.26
mmol) was then added and the solution stirred for 2 h.
Removal of the solvent and chromatography gave two
4.16. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CPh2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5c) with lithium
triethylborohydride
/
/
A redÁ
/
orange dichloromethane (50 cm3) solution of
78 8C and
5c (0.150 g, 0.22 mmol) was cooled to ꢂ
/
bands. The first (orange) eluted with dichloromethaneꢁ
/
lithium triethylborohydride (0.25 cm3 of 1 M thf
solution, 0.25 mmol) was added. The solution darkened,
became cloudy and was allowed to warm over 0.5 h,
after which time distilled water (five drops) was added.
Removal of the solvent and chromatography of the
residue gave four bands. The first (yellow) eluted with
hexane (3:7) and gave 50 mg (10%) of trans-8 as an
orange residue. The second band (orange) eluted with
dichloromethane/hexane (2:3) and gave 250 mg (48%) of
cis-8 as an orange residue. Both isomers were combined
for crystallisation, performed by layering a saturated
dichloromethane solution with hexane.
dichloromethaneꢁhexane (1:4) and gave 10 mg (8%) of
/

J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á
/40
39
Table 4
Crystallographic data for complexes 5b, 5c and 8
5b
5c
8
Formula
C
18H19BF4O2Ru2
red block
0.20ꢃ0.15ꢃ
monoclinic
C28H23BF4O2Ru2
orange block
C18H18O2Ru2
orange block
Colour and habit
Crystal dimensions (mm3)
Crystal system
/
/0.10
0.35ꢃ/0.30ꢃ/0.20
0.50ꢃ
/
0.25ꢃ0.25
/
monoclinic
P21/n (no. 14)
orthorhombic
P212121 (no. 19)
Space group
Unit cell dimensions
P21/c (no. 14)
˚
a (A)
9.4469(8)
14.379(2)
13.9161(14)
90
10.8458(12)
20.903(3)
10.8643(15)
90
9.852(2)
11.833(2)
14.250(3)
90
˚
b (A)
˚
c (A)
a (8)
b (8)
g (8)
94.341(7)
90
91.050(10)
90
90
90
3
˚
V (A )
1884.9(4)
193
1.65
2462.6(6)
293
1.28
1661.3(6)
293
1.82
T (K)
m (mmꢂ1
Absorption correction
)
psi-scan
Transmission factors (min, 0.785, 0.848
max)
multi-scan [18]
0.683, 0.774
psi-scan
0.582,.634
2u (min, max) (8)
Indices range
4.1, 50.0
35h 5
l 516
3.9, 55.0
4.5, 54.4
ꢂ
/
/
/
11, ꢂ
/
125
/
k 5
/
17, ꢂ
/
165
/
ꢂ/
145
/
h 5
/
10, ꢂ
/
265
/
k 5
/
27, ꢂ
/
125
/
ꢂ/
125/h 5
/
7, ꢂ
/
145
/
k 5
/
11, ꢂ
/
/
l 514
/
85l 518
/
/
Total data
Unique data
3186
2995
2664
1.06
15835
5641
4551
0.98
2114
1930
1855
1.08
Observed data [Iꢀ 2s(I)]
Goodness-of-fit (all data)
wR2 (all data)
/
11.6%
4.3%
0.0523, 10.9789
5.7%
2.5%
7.0%
2.7%
R1 (observed data)
Weighting parameters (a,
b) a
0.0291, 0
0.0343, 1.9613
Flack parameter [19]
0.45(9)
1/[s2(Fo2)ꢁ
/
aP2ꢁ
/
bP)], Pꢀ
/
(Fo2ꢁ2Fc2)/3.
/
a
wꢀ
/
orangeÁ
/
yellow [Ru2(CO)2(m-h2,h2-CPh2Ä
C5H5)2] (13), the small quantity of which did not allow
satisfactory analytical data to be obtained. The second
/
CÄ
/
CHMe)(h-
with dichloromethaneꢁhexane (3:7) and gave 68 mg
/
(52%) of [Ru2(CO)2(m-h2,h2-CPh2Ä
/
CÄ
/
CÄCH2)(h-
/
C5H5)2] (15)11 as an orange powder, identified by IR
and NMR spectroscopy. The second (pale yellow) eluted
band (orange) eluted with dichloromethaneꢁ
(1:4) and gave 30 mg (23%) of orange [Ru2(CO)2(m-
h2,h2-CPh2Ä
CHCHÄCH2)(h-C5H5)2] (12). The third
band (orange) eluted with dichloromethaneꢁhexane
(3:7) and gave 45 mg (34%) of orange trans-
[Ru2(CO)(m-CO){m-h1,h3-C(CHPh2)CHÄ
CH2}(h-
C5H5)2] (11). The final band (orange) eluted with
dichloromethaneꢁhexane (2:3) and gave 45 mg (34%)
of cis-11 as an orange residue, recrystallised from
dichloromethaneꢁhexane.
/hexane
with dichloromethaneꢁ
/
hexane (2:3) and gave 30 mg
/
/
(22%) of [Ru2(CO)(m-CO){m-h1,h3-C(CPh2Me)CHÄ
/
/
CH2}(h-C5H5)2] (14) as an oily orange residue. At-
tempts to crystallise 14 were unsuccessful and satisfac-
tory analytical data were not obtained.
/
/
4.18. Reaction of 5c with 1,8-diazobicyclo[5.4.0]undec-
7-ene (DBU)
/
4.17. Reaction of [Ru2(CO)(m-CO)(m-h2,h3-CPh2Ä
CCHÄCH2)(h-C5H5)2][BF4] (5c) with methyl lithium
/
An excess of DBU (0.4 cm3, 0.3 mmol) was added to
an orange dichloromethane (30 cm3) solution of 5c (55
mg, 0.08 mmol) and the mixture was stirred for 5 min.
Removal of the solvent and chromatography of the
residue gave two bands. The first (orange) eluted with
dichloromethane/hexane (1:9) and gave 30 mg (63%) of
15 as an orange powder. The second band (orange)
eluted with acetone and gave approximately 1 mg of an
unidentified orange substance.
/
An excess of methyl lithium (0.2 cm3 of 1.6 M diethyl
ether solution, 0.3 mmol) was added to a thf (120 cm3)
suspension of 5c (150 mg, 0.22 mmol). The solution
darkened from orange to dark red and after stirring for
0.5 h solvent was removed and the residue chromato-
graphed, giving two bands. The first (orange) eluted

40
J.N.L. Dennett et al. / Inorganica Chimica Acta 354 (2003) 29Á40
/
4.19. X-ray diffraction studies
Acknowledgements
Crystallographic data for compounds 5b, 5c and 8 are
given in Table 4. Data for 5b and 8 were recorded with a
scintillation counter on a Bruker-AXS P4 four circle
diffractometer [13]. Data for 5c were collected on a
Bruker-AXS SMART three-circle diffractometer
equipped with a CCD area detector [14]. Intensity data
for 5c were integrated from a series of exposures each
We are grateful to the EPSRC for the award of
Research Studentships to JLD and ALG.
References
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˚
0.71073 A) was
monochromated Mo Ka radiation (lꢀ
/
used. The structures were solved by direct methods and
refined [16]. In all three structures, the cyclopentadienyl
hydrogen atoms were constrained to ideal geometries
and assigned isotropic thermal parameters 1.2 times that
of their parent carbon atom. The phenyl hydrogen
atoms in 5c were similarly treated. The methyl hydrogen
atoms in 5b and 8 were positioned using a rotating
group refinement and assigned isotropic thermal para-
meters 1.5 times that of their parent carbon atom. All
other hydrogen atoms in all of the structures were
located in the electron density difference map, assigned
isotropic displacement parameters 1.2 times that of their
parent carbon atom and allowed to refine without
positional constraints. Complex neutral-atom scattering
factors were used [17]. Compound 8 was solved and
refined in a chiral space group as a racemic twin.
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5. Supplementary material
[14] SMART Diffractometer Control Software, Bruker-AXS Inc.,
Madison, WI, 1998.
Crystallographic data for the structural analysis have
been deposited with the Cambridge Crystallographic
[15] SAINT Integration Software, Bruker-AXS Inc., Madison, WI,
1998.
[16] SHELXTL Program Suite, Bruker AXS Inc., Madison, WI, 2001.
[17] International Tables for Crystallography, vol. C, Kluwer, Dor-
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Data Centre, CCDC Nos. 202103Á202105. Copies of
this information may be obtained free of charge from
The Director, CCDC, 12 Union Road, Cambridge, CB2
/
[18] G.M. Sheldrick, SADABS, University of Gottingen, Germany,
¨
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[19] H.D. Flack, Acta Crystallogr., Sect. A 39 (1983) 876.
1EZ, UK (fax: ꢁ
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