Reactivity of a coordinatively unsaturated diruthenium hydride: Reversible insertion of alkynes

Article abstract of DOI:10.1039/b210171h

The chemistry of the coordinatively unsaturated hydridodiruthenium complex cation [Ru₂(μ-H)(μ-CO)(CO)₃-(μ-dppm) ₂]⁺, 1, is described. Complex 1 adds CO to give [Ru ₂(μ-H)(μ-CO)(CO)₄(μ-dppm)₂] ⁺, reacts with hydrogen to give [Ru₂(μ-H) ₂(CO)₄(μ-dppm)₂] and H⁺ and, in the presence of Et₃N, is an efficient catalyst for decomposition of formic acid to CO₂ and H₂. Complex 1 reacts easily with acetylene to give [Ru₂(μ-CH=CH₂)(CO) ₄(μ-dppm)₂]⁺, with PhCCH to give the coordinatively unsaturated alkenyl complex [Ru₂{C(Ph)=CH ₂}(μ-CO)₂(CO)₂(μ-dppm)₂] ⁺ which then rearranges to the isomeric, coordinatively saturated complex [Ru₂(E-μ-CH=CHPh)(CO)₄(μ-dppm) ₂]⁺, and reacts reversibly with PhCCPh to give [Ru ₂{Z-C(Ph)=CHPh}(μ-CO)₂(CO)₂(μ-dppm) ₂]⁺. The Royal Society of Chemistry 2003.

Full text of DOI:10.1039/b210171h

View Article Online / Journal Homepage / Table of Contents for this issue
Reactivity of a coordinatively unsaturated diruthenium hydride:
reversible insertion of alkynes
Yuan Gao, Michael C. Jennings and Richard J. Puddephatt*
Department of Chemistry, University of Western Ontario, London, Canada N6A.
E-mail: pudd@uwo.ca
Received 16th October 2002, Accepted 20th November 2002
First published as an Advance Article on the web 11th December 2002
The chemistry of the coordinatively unsaturated hydridodiruthenium complex cation [Ru2(µ-H)(µ-CO)(CO)3-
(µ-dppm)2]ϩ, 1, is described. Complex 1 adds CO to give [Ru2(µ-H)(µ-CO)(CO)4(µ-dppm)2]ϩ, reacts with hydrogen
to give [Ru2(µ-H)2(CO)4(µ-dppm)2] and Hϩ and, in the presence of Et3N, is an efficient catalyst for decomposition of
formic acid to CO and H . Complex 1 reacts easily with acetylene to give [Ru (µ-CH᎐CH )(CO) (µ-dppm) ]ϩ, with
᎐
2
2
2
2
4
2
PhCCH to give the coordinatively unsaturated alkenyl complex [Ru {C(Ph)᎐CH }(µ-CO) (CO) (µ-dppm) ]ϩ which
᎐
2
2
2
2
2
then rearranges to the isomeric, coordinatively saturated complex [Ru (E-µ-CH᎐CHPh)(CO) (µ-dppm) ]ϩ, and reacts
᎐
2
4
2
reversibly with PhCCPh to give [Ru {Z-C(Ph)᎐CHPh}(µ-CO) (CO) (µ-dppm) ]ϩ.
᎐
2
2
2
2
Introduction
Coordinatively unsaturated hydride complexes are of interest
because of their important role in homogeneous catalysis.1
There are still relatively few coordinatively unsaturated bi-
nuclear hydrides, though there is clearly potential for interesting
chemistry and catalysis with such compounds, as shown for
the cationic diruthenium hydride [Ru2(µ-H)(µ-CO)(CO)3-
(2)
unsaturated dihydride [Ru2(µ-H)(H)(µ-CO)(CO)2(µ-dppm)2], 5,
reacts with CO to give hydrogen and complex 3.5 It is likely that
CO reacts with 5 to give the adduct 6, which is an isomer of 4,
and which then eliminates hydrogen as shown in eqn. (3).
(µ-PNP)2]ϩ, PNP᎐RN{P(OR) } .2 The related dihydrido
᎐
2
2
complex with more robust Ph2PCH2PPh2 (dppm) ligands,
[Ru2(µ-H)(H)(µ-CO)(CO)2(µ-dppm)2], is formed as an inter-
mediate in the interconversion of HCO2H and H2/CO2 using
[Ru2(µ-CO)(CO)4(µ-dppm)2] as catalyst,3 and in the catalytic
transfer hydrogenation of internal alkynes using formic acid as
the hydrogen source.4 However, its chemistry has not been stud-
ied extensively because it could not be isolated in good yield
from these reactions. Recently, the reaction of MeOSO2CF3
with [Ru2(µ-CH2)(CO)4(µ-dppm)2] was shown to give ethyl-
ene and the coordinatively unsaturated 32-electron complex
[Ru2(µ-H)(µ-CO)(CO)3(µ-dppm)2][O3SCF3],5 1, in good yield.
The chemistry of this coordinatively unsaturated hydrido-
diruthenium complex is described in this paper.
(3)
Results and discussion
The reaction of 1 with formic acid
The reactions of complex 1 with CO and H2
Complex 1 reacted slowly with HCO2H in either CD2Cl2 or
acetone-d6 solution at room temperature to give the known
complex cation [Ru2(µ-HCO2)(CO)4(µ-dppm)2]ϩ, 7,3 according
to eqn. (4). The catalytic decomposition of formic acid did not
occur under these conditions.3
Carbon monoxide reacted rapidly with the coordinatively
unsaturated hydride [Ru2(µ-H)(µ-CO)(CO)3(µ-dppm)2]ϩ, 1,
to give the 34-electron complex [Ru2(µ-H)(µ-CO)(CO)4-
(µ-dppm)2]ϩ, 2, according to eqn. (1). Complex 2 can be formed
independently by protonation of the complex [Ru2(µ-CO)-
(CO)4(µ-dppm)2], 3.3,6
(4)
(1)
However, in the presence of the base triethylamine, complex 1
was an excellent catalyst for decomposition of H13CO2H in
acetone-d6 at room temperature to give H2 and 13CO2 as deter-
Complex 1 reacted reversibly with hydrogen to give the
known dihydride complex [Ru2(µ-H)2(CO)4(µ-dppm)2], 4,3
according to eqn. (2). The reaction was readily monitored by
NMR and it was shown that higher pressure of hydrogen gave
faster, more complete reaction, but no intermediates were
detected.
1
mined by H and 13C NMR. When reaction was complete, the
ruthenium products were 1, 2, 3, 4, 5 and [Ru2(HCO2)-
(H)(CO)4(µ-dppm)2], 8,3 in approximate ratio 1 : 2 : 3 : 4 : 5 : 7 =
1 : 0.4 : 0.5 : 0.25 : 0.2 : 0.6 as determined from integration of
the 31P{H} NMR spectrum. The catalyst remained active for
decomposition of more formic acid. When monitored by NMR
Complex 4 is coordinatively saturated and it failed to react
with CO under mild conditions. In contrast, the coordinatively
T h i s j o u r n a l i s © T h e R o y a l S o c i e t y o f C h e m i s t r y 2 0 0 3
D a l t o n T r a n s . , 2 0 0 3 , 2 6 1 – 2 6 5
261

View Article Online
Table 1 Selected bond distances (Å) and angles (Њ) for complex 9
at Ϫ25 ЊC, the above reaction was slow and only traces of com-
plex 4 could be detected along with 1. At Ϫ10 ЊC, the formation
of 4 proceeded faster and 13CO2 and hydrogen were detected. At
5 ЊC, the catalytic decomposition of formic acid proceeded
much faster and no formic acid could be detected after 30 min-
utes. The ruthenium complexes 1–5 and 8 were all present at
completion of the reaction. The catalysis is known to be
retarded by CO and by acid, so the use of a coordinatively
unsaturated catalyst under basic conditions is optimal for high
catalytic activity. Possible reactions for interconversion of the
complexes observed during and after catalysis are shown in
Scheme 1.
Ru(1)–C(11)
Ru(2)–C(21)
Ru(1)–C(10)
Ru(2)–C(20)
Ru(1)–P(1)
Ru(2)–P(2)
Ru(1)–P(3)
1.880(6)
1.897(7)
1.920(7)
1.892(8)
2.353(2)
2.377(2)
2.363(2)
Ru(2)–P(4)
Ru(1)–C(3)
Ru(2)–C(3)
Ru(1)–Ru(2)
Ru(2)–C(4)
C(3)–C(4)
2.356(1)
2.056(7)
2.294(6)
2.8777(7)
2.289(6)
1.361(9)
P(1)–Ru(1)–P(3)
P(2)–Ru(2)–P(4)
P(1)–Ru(1)–Ru(2)
P(2)–Ru(2)–Ru(1)
P(3)–Ru(1)–Ru(2)
178.79(6)
173.63(5)
90.34(4)
91.10(4)
90.41(4)
P(4)–Ru(2)–Ru(1)
C(4)–C(3)–Ru(1)
C(4)–C(3)–Ru(2)
Ru(1)–C(3)–Ru(2)
93.68(4)
129.9(5)
72.5(4)
82.6(2)
Fig. 1 A view of the structure of the cationic µ-vinyl complex 9. Only
the ipso carbon atoms of the phenyl groups are shown for clarity.
The low symmetry of complex 9, as determined by the solid
state structure, is maintained in solution. Thus, the 31P NMR
spectrum at room temperature exhibits an ABCD pattern of
peaks indicating that all four phosphorus atoms are inequiv-
alent. Four resonances were observed in the 1H NMR spectrum
for the CH2P2 protons (one coupled pair at δ 4.70 and 3.92 and
the other at δ 3.92 and 2.98). The vinyl protons were observed at
Scheme 1
δ 7.60 [RuCH] and 3.98 [overlapping peaks for ᎐CH protons],
᎐
2
Reactions of complex 1 with alkynes
consistent with NMR parameters observed in other µ-alkenyl
complexes.2,4
The reaction of complex 1 with the alkynes HCCH, PhCCH
and PhCCPh were studied and each gave a different reac-
tion. The reaction of 1, as the triflate salt, with HCCH in
toluene solution occurred with immediate precipitation of a
yellow solid, that was characterized as [Ru (µ-HC᎐CH )-
(CO)4(µ-dppm)2][CF3SO3], 9[CF3SO3], according to eqn. (5).
When the reaction of complex 1 with acetylene was carried
out in CD2Cl2 at room temperature, a black material, which was
insoluble in common organic solvents, was formed slowly and is
presumed to be polyacetylene. Complex 9 in CD2Cl2 at room
temperature also reacted slowly with acetylene to form this
black material. A complex mixture of ruthenium-containing
products was formed in each case. The precipitation of complex
9 when the reaction of 1 with acetylene is carried out in toluene
solution is probably important, since further reaction with
acetylene does not then occur.
᎐
2
2
(5)
The reaction of phenylacetylene with a solution of 1 in
CD2Cl2 at room temperature rapidly gave a complex 10 that
isomerized to complex 11 over a period of two hours (Scheme
2). These same compounds are formed in the reaction of
the coordinatively saturated hydride [Ru2(µ-H)(µ-CO)(CO)4-
(µ-dppm)2]ϩ, 2, with PhCCH in acetone-d6 or CD2Cl2 but, in
this case, the rate of formation of complex 10 is similar to the
rate of its rearrangement to 11. Complex 11 was characterized
The molecular structure of the cation 9 is shown in Fig. 1,
and selected bond distances and angles are summarized in
Table 1. The structure contains a trans,trans-Ru2(µ-dppm)2 unit
with the Ru2P4C2 atoms in the boat conformation. There are
four terminal carbonyl ligands which lie roughly in a plane per-
pendicular to the Ru2P4 plane. The vinyl group is σ-bonded to
Ru(1) [Ru(1)–C(3) = 2.056(7) Å] and π-bonded to Ru(2) [Ru(2)–
C(3) = 2.294(6), Ru(2)–C(4) = 2.289(6) Å]. The bond distance
crystallographically as [Ru (µ-CH᎐CHPh)(CO) (µ-dppm) ]ϩ,
᎐
2
4
2
and the intermediate complex, 10, was tentatively (and errone-
ously) characterized as [Ru2(µ-CPhCH2) (CO)4(µ-dppm)2]ϩ.4 In
the present work, the reaction of complex 1 with PhCCH in
toluene solution led to precipitation of complex 10 and so it
could be isolated in pure form for the first time, and so charac-
terized more completely.
C(3)–C(4) = 1.361(9) Å is close to a normal C᎐C double bond
᎐
[1.34 Å] and the angle Ru(1)–C(3)–C(4) = 129.9(5)Њ. The dis-
tance Ru(1)–Ru(2) = 2.8777(7) Å is consistent with a metal–
metal single bond.6 The µ-vinyl group acts as a three-electron
ligand and the complex is coordinatively saturated, with struc-
tural features similar to those of other µ-alkenyl complexes.2,4
The IR spectrum of 10 exhibited two peaks at 2060 and 2016
cmϪ1 and one strong peak at 1730 cmϪ1, indicating the presence
D a l t o n T r a n s . , 2 0 0 3 , 2 6 1 – 2 6 5
262

View Article Online
Table 2 Selected NMR data for complexes 10 and 12
Complex
10
12
δ(CHaHbP2)
3.20, 3.32
4.72, 5.44
3.20, 3.37
6.02
δ(RuC᎐CH )
᎐
δ(RuCPh)
6.17(o), 6.58(m), 6.66(p)
26
6.07(o), 6.68(m), 6.80(p)
26
δ(CHaHbP2)
δ(RuC᎐CH)
111.6
185
127.8
182
᎐
δ(RuCPh)
δ(RuCPh)
δ(RuCO)
δ(Ru2–µ-CO)
δ(RuP)
144(i), 126(o), 127(m), 125(p)
194, 195
253, 259
144(i), 128(o), 128(m), 125(p)
194, 195.5
253, 260
25.0, 26.8
22.9, 24.2
1
a The alkenyl and phenyl carbon assignments were confirmed by the H13C correlated gHSQC and gHMBC spectra. b Carbonyl resonances were
identified by using 13CO enriched samples.
(6)
of the precursor complex 1. The structure of 12 was therefore
established by comparing its NMR parameters with those of
complex 10 (Table 2). The alkenyl hydrogen was located at
δ 6.02, while the alkenyl carbon atoms were at δ 182 (α-C) and
127.8 (β-C), in the range expected for η1-alkenyl groups. Two
1
resonances were observed for the CHaHbP2 protons in the H
NMR and two signals for the dppm phosphorus atoms in the
31P NMR, indicating that the complex has effective Cs sym-
metry. There were two bridging and two terminal carbonyl
resonances, very similar to those in 10.
The equilibrium constant was determined as K = 3.8 MϪ1,
from the equilibrium concentrations of 1, 12 and PhCCPh,
which were determined by NMR. Although easy insertion of
an alkyne into a Ru–H bond is well-known, the direct observ-
ation of an equilibrium between the hydride ϩ alkyne and the
Scheme 2
alkenyl complex is rare.2–8 No further rearrangement of 12 to
form a bridging alkenyl complex analogous to 11 was observed,
presumably because steric effects prevent it.
of both terminal and bridging carbonyl ligands. Furthermore,
the 13C{H} NMR spectrum of a 13CO labeled sample of 10
displayed two multiplets at δ 259.2 and 252.6, in the range for
bridging CO, and two multiplets δ 194.8 and 194.4, in the range
for terminal CO. Since there are two bridging carbonyl ligands,
the styryl group cannot be bridging as previously proposed.4
Discussion
Complex 1 has the properties of a coordinatively unsaturated
(32-electron) binuclear compound. It easily adds CO to give the
34-electron complex 2 (eqn. (1)) and reacts with hydrogen to
give the neutral dihydridodiruthenium complex 4 (eqn. (2)). In
the presence of base, it is an excellent catalyst for decom-
position of formic acid. Its reactions with alkynes are particu-
larly interesting as shown in eqns. (5) and (6) and in Scheme 2.
The reactivity pattern can be understood in terms of the steric
environment created by the trans,trans-[Ru2(µ-dppm)2] unit.
Other ligands tend to lie in the plane containing the RuRu axis
and perpendicular to the Ru2P4 plane in order to avoid steric
interactions with the phenyl substituents of the dppm ligands.
The vinyl group in complex 9 is readily accommodated in the
bridging position and no other isomers are observed. Phenyl-
acetylene can approach the vacant site in complex 1 in two
orientations as shown in Scheme 2 and, once coordinated, can-
not rotate due to steric hindrance. The favored orientation evi-
dently leads to the kinetic product 10, having a one-electron
alkenyl ligand. The α-phenyl substituent is bulky and formation
of the three-electron µ-alkenyl group, in which the alkenyl
group must lie across the Ru–Ru axis, is prevented by phenyl–
phenyl steric repulsions. In principle, it could form a three-elec-
tron vinyl group at a single ruthenium center, but the NMR
data clearly show that it does not.7 Complex 10 slowly isomer-
izes to 11, in which the β-phenyl substituent can be accom-
modated in the µ-alkenyl group, and so allows coordinative
The styrenyl protons of the RuC(Ph)᎐CH group appear as
᎐
2
singlets in the 1H NMR at δ 4.72 and 5.44, and both are directly
bonded to an alkenyl carbon at δ = 111.6. The RuC(Ph)᎐
᎐
carbon resonance was observed at δ 185, with no directly
attached protons. These NMR parameters are consistent with a
one-electron, but not with a three-electron, alkenyl group, for
which δ(α-C) = 220–300 and δ(β-C) < 80.7 For comparison, the
complex TpN(CO)(PhCCH)W(η1-C(Ph)᎐CH ) gives δ(α-C) =
᎐
2
161.8 and δ(β-C) = 119.9 for the W(η1-CPh᎐CH ) group.7
᎐
2
The mechanism described in Scheme 2 requires that the
formation of the σ-alkenyl complex 10 [RuC(Ph)᎐CH ] be
᎐
2
reversible in order to allow the rearrangement to the isomeric
σ,π-alkenyl complex 11 [E-RuCH᎐CHPh]. It is likely that
᎐
the α-phenyl substituent in 10 prevents formation of the
σ,π-alkenyl because of steric hindrance with the phenyl
substituents of the dppm ligands.
The reaction of PhCCPh with a solution of 1 in CD2Cl2 was
reversible and gave an equilibrium between the starting
materials and a new alkenyl complex [Ru (η1-CPh᎐CHPh)-
᎐
2
(µ-CO)2(CO)2(µ-dppm)2]ϩ, 12, according to eqn. (6).
Solutions containing 12 as the only detectable ruthenium
complex could be prepared by using a large excess of PhCCPh,
but efforts to isolate pure 12 or to grow crystals from this solu-
tion were unsuccessful and always resulted in the regeneration
D a l t o n T r a n s . , 2 0 0 3 , 2 6 1 – 2 6 5
263

View Article Online
Table 3 Crystal data and structure refinement for 9[OTf]ؒ1.5CH2Cl2
saturation. The isomerization must presumably occur by a
β-elimination-reinsertion process as shown in Scheme 2. The
reversibility of the insertion reaction is shown directly in the
reaction of complex 1 with diphenylacetylene, which forms only
the one-electron alkenyl derivative 12. Such easy reversible
insertion of alkynes is rare and this appears to be the only
known example in ruthenium hydride chemistry.2–8
Formula, FW
C58.5H49Cl3F3O7P4Ru2S,
1385.41
150(2)
Temperature/K
Wavelength/Å
Crystal system, space group
a/Å
0.71073
Triclinic, P1
11.2830(8)
¯
b/Å
15.3642(14)
c/Å
α/Њ
18.1169(16)
87.153(3)
Experimental
β/Њ
75.089(4)
All manipulations were carried out under a dry nitrogen
atmosphere using either standard Schlenk techniques or a
glove box. Toluene was dried by distillation from sodium-
benzophenone and CH2Cl2 was distilled from CaH2. [Ru2-
(µ-CO)(µ-H)(CO)3(µ-dppm)2][OSO2CF3], 1[OSO2CF3], was
synthesized according to the published procedure.5 NMR
spectra were recorded using Varian INOVA 600 or 400 or a
Mercury 400 spectrometer. IR spectra were recorded by using
a Perkin-Elmer FTIR 2000 spectrometer.
γ/Њ
73.662(4)
2911.5(4)
1.580
0.864, 1396
0.20 × 0.18 × 0.05
13897, 11530
[R(int) = 0.041]
Integration
11530/0/616
R1 = 0.0659, wR2 = 0.1691
R1 = 0.1000, wR2 = 0.1855
Volume/Å3, Z
Density (calc.)/Mg mϪ3
Absorption coefficient/mmϪ1, F(000)
Crystal size/mm
Reflections, independent reflections
Absorption correction
Data/restraints/parameters
R indices [I > 2σ(I )]
R indices (all data)
The reaction of 1 with CO
᎐
A stream of CO was passed through a solution of 1 (10 mg,
0.008 mmol) in CD2Cl2 (0.5 mL) in a septum-sealed NMR tube
for one minute, giving a color change from orange–red to
orange–yellow. The product [Ru2(µ-H)(µ-CO)(CO)4(µ-dppm)2]-
[OTf], 2[OTf], was identified by its 1H and 31P NMR spectra as
the only ruthenium complex in solution, by comparison with an
authentic sample.3
Polymerization of HC᎐CH in the presence of 1
᎐
A stream of HCCH was bubbled through a solution of
1 (10 mg, 0.008 mmol) in CD2Cl2 (0.5 mL) in a septum-
sealed NMR tube for 5 min. A black solid was observed after
0.5 h and increased with time. The solid was isolated by centri-
fuging. XPS analysis showed only carbon, with Ru and P
absent.
The reaction of 1 with H2
[Ru (ꢁ1-PhC᎐CH )(CO) (ꢀ-dppm) ][OTf], 10[OTf]
᎐
2
2
4
2
A stream of H2 was bubbled through a solution of 1 (10 mg,
0.008 mmol) in CD2Cl2 (0.5 mL) in a septum-sealed NMR tube
for 5 min. A slow transformation of 1 to [Ru(µ-H)2(CO)4-
(µ-dppm)2], 4, identified by its NMR spectrum,3 occurred.
To a solution of 1 (20 mg, 0.016 mmol) in toluene-d8 (0.5 mL)
in a septum-sealed NMR tube was added PhCCH (3 µL, 0.027
mmol) by microsyringe to give the product as a pale yellow
precipitate, which was washed with pentane and dried under
vacuum. Yield: 14 mg, 66%. IR (Nujol, cmϪ1): ν(CO) = 2060
and 2016 (terminal CO); 1730 (bridging CO). Anal. calc. for
C63H51F3O7P4Ru2S: C, 56.67; H, 3.85. Found: C, 56.91; H,
3.46%. NMR in CD2Cl2 at Ϫ10 ЊC: see Table 2.
The reaction of 1 with HCO2H
To a solution of 1 (10 mg, 0.008 mmol) in CD2Cl2 (0.5 mL) in a
septum-sealed NMR tube, was added HCO2H (1.5 µL, 0.03
mmol) by microsyringe. The color of the solution slowly
changed from orange–red to orange–yellow. After 24 h, the
product was identified as [Ru2(µ-HCOO)(CO)4(dppm)2]ϩ, 7,
by its 1H and 31P NMR spectra.3
[Ru (ꢀ-ꢁ1,ꢁ2-CH᎐CHPh)(CO) (ꢀ-dppm) ][OTf], 11[OTf]
᎐
2
4
2
To a solution of 1 (10 mg, 0.008 mmol) in CD2Cl2 (0.5 mL) in a
septum-sealed NMR tube at room temperature was added
PhCCH (2 µL, 0.018 mmol) by microsyringe. After 3 h, com-
plex 11 was the only ruthenium complex present and was
identified by its NMR spectra.4 The same product was formed
from a solution of complex 10 in CD2Cl2 after 3 h.
The reaction of 1 with HCO2H/Et3N
To a solution of 1 (10 mg, 0.008 mmol) in acetone-d6 (0.5 mL)
in a septum-sealed NMR tube was added HCO2H (4 µL, 0.08
mmol) and Et3N (3.8 µL, 0.03 mmol). Gas evolution was
observed immediately, and no formic acid could be detected
after 20 min. The known complexes 2, 4, [Ru(µ-H)(H)(µ-CO)-
(CO)2(µ-dppm)2], 5, [Ru2(H)(HCOO)(CO)4(µ-dppm)2], 8, and
[Ru(µ-CO)(CO)4(µ-dppm)2], 3, along with unreacted 1, were
identified by their 31P NMR spectra.
[Ru (ꢁ1-CPh᎐CHPh)(CO) (ꢀ-dppm) ][OTf], 12[OTf]
᎐
2
4
2
To a solution of 1 (10 mg, 0.008 mmol) in CD2Cl2(0.5 mL) in an
NMR tube was added a large excess PhCCPh (54 mg, 0.2997
mmol). There was an immediate color change and the solution
was shown to contain complex 12 along with some of the start-
ing material 1 and excess PhCCPh. NMR in CD2Cl2 at 20 ЊC:
see Table 2.
[Ru (ꢀ-ꢁ1:ꢁ2-CH᎐CH )(CO) (ꢀ-dppm) ][OTf], 9[OTf]
᎐
2
2
4
2
A stream of HCCH was bubbled through a solution of 1 (15
mg, 0.012 mmol) in toluene-d8 (0.5 mL) in a septum-sealed
NMR tube for 20 s, to form the product as a pale-yellow pre-
cipitate, which was washed with pentane and dried under
vacuum. Yield: 11 mg, 73%. IR (Nujol, cmϪ1): ν(CO) = 2017,
1988, 1948 and 1938. NMR in CD2Cl2 at 20 ЊC: δ(1H) = 7.60
Determination of Keq for the reaction of 1 with PhCCPh
To a solution of 1 (38 mg, 0.0308 mmol) in CD2Cl2 (0.034 mL)
in an NMR tube was added PhCCPh (36 mg, 0.1998 mmol).
The solution was set aside for 6 h to ensure that equilibrium was
reached. The relative concentrations of 1 and 12 in the equi-
librium mixture were determined by integration of the 1H
NMR spectrum for the CH2P2 protons, and the absolute con-
centrations were then determined to give Keq = 3.7 MϪ1. The
same procedure was repeated with varying concentrations of
PhCCPh to give the mean value of Keq = 3.8(2) MϪ1.
[m, 1H, CH᎐CH ]; 3.98 [overlapping m, 2H, H C᎐CH];
᎐
᎐
2
2
4.70 [m, 1H, P–CH–P], 3.92 [m, 2H, P–CH–P], 2.98 [m, 1H,
P–CH–P]; δ(31P) = 49.85 [ddd, J(PaPb) = 247, J(PaPc) = 50,
J(PaPd) = 25 Hz, Pa]; 27.85 [ddd, J(PaPb) = 247, J(PbPd) = 68,
J(PbPc) = 28 Hz, Pb]; 35.30 [ddd, J(PcPd) = 279, J(PaPc) = 50,
J(PbPc) = 28 Hz, Pc]; 32.30 [ddd, J(PcPd) = 279, J(PaPd) = 25,
J(PbPd) = 68 Hz, Pd].
D a l t o n T r a n s . , 2 0 0 3 , 2 6 1 – 2 6 5
264

View Article Online
Structure determination for complex 9
thanks the Government of Canada for a Canada Research
Chair.
Crystals of [Ru (µ-η1:η2-CH᎐CH )(CO) (µ-dppm) ][OTf]ؒ
᎐
2
2
4
2
1.5CH2Cl2 were grown by slow diffusion of pentane into a di-
chloromethane solution. A crystal was mounted on a glass
fiber. Data were collected at 150 K using a Nonius Kappa-CCD
diffractometer using COLLECT (Nonius, 1998) software. The
unit cell parameters were calculated and refined from the full
data set. Crystal cell refinement and data reduction was carried
out using the Nonius DENZO package. The data were scaled
using SCALEPACK (Nonius, 1998) and no other absorption
corrections were applied. The crystal data and refinement
parameters are listed in Table 3.
The SHELXTL 5.1 (G. M. Sheldrick, Madison, WI) pro-
gram package was used to solve the structure by the Patterson
method, followed by successive difference Fouriers. All non-
hydrogen atoms were refined anisotropically. The hydrogen
atoms were calculated geometrically and were riding on their
respective carbon atom.
References
1 (a) D. Bingham, D. E. Webster and P. B. Wells, J. Chem. Soc.,
Dalton Trans., 1974, 1514, 1519; (b) R. Noyori, Angew. Chem., Int.
Ed. Engl., 1997, 36, 285; (c) R. Cramer, J. Am. Chem. Soc., 1965, 87,
4717; (d ) J. F. Knifton, J. Org. Chem., 1976, 41, 2885; (e) I. Ojima,
M. Eguchi and M. Tzamarioudaki, Comprehensive Organometallic
Chemistry II, Pergamon, Oxford, 1995, vol. 12, ch. 2.
2 K. J. Edwards, J. S. Field, R. J. Haines, B. D. Homann, M. W. Stewart,
J. Sundermeyer and S. F. Woollam, J. Chem. Soc., Dalton Trans.,
1996, 4171.
3 (a) Y. Gao, J. Kuncheria, G. P. A. Yap and R. J. Puddephatt, Chem.
Commun., 1998, 2365; (b) Y. Gao, J. Kuncheria, G. P. A. Yap and
R. J. Puddephatt, J. Chem. Soc., Dalton Trans., 2000, 3212.
4 Y. Gao, M. C. Jennings and R. J. Puddephatt, Can. J. Chem., 2001,
79, 915.
5 Y. Gao, M. C. Jennings and R. J. Puddephatt, Organometallics, 2001,
20, 1882.
6 (a) P. Legzdins, S. A. Lumb and S. J. Rettig, Organometallics, 1999,
18, 3128; (b) S. G. Feng, P. S. White and J. L. Templeton, J. Am.
Chem. Soc., 1992, 114, 2951.
CCDC reference number 195497.
See http://www.rsc.org/suppdata/dt/b2/b210171h/ for crystal-
lographic data in CIF or other electronic format.
7 D. S. Frohnapfel and J. L. Templeton, Coord. Chem. Rev., 2000,
206–207, 199.
8 M. K. Anwar, G. Hogarth, O. S. Senturk, W. Clegg, S. Doherty and
M. R. J. Elsegood, J. Chem. Soc., Dalton Trans., 2001, 341.
Acknowledgements
We thank the NSERC (Canada) for financial support. R. J. P.
D a l t o n T r a n s . , 2 0 0 3 , 2 6 1 – 2 6 5
265