The reaction between [(η5-C7H9)RuCl(H)(PPh3) 2] and dihydrogen

Article abstract of DOI:10.1016/S0022-328X(97)00428-2

[(η⁵-C₇H₉)RuCl(PPh₃) ₂] has been shown to react with hydrogen to give [(η³-C₇H₁₁)RuCl(PPh₃) ₂] initially, and then [RuCl(H)(PPh₃)₃], [Ru₂H₄Cl₂(PPh₃₎₄], and unidentified compound(s). This is a rare example of the hydrogenation of a coordinated ligand, where the ligand remains coordinated to the metal. It is suggested that the reverse reaction, involving the conversion of [(η³-C₇H₁₁)RuCl(PPh₃) ₂] to [(η⁵-C₇H₉)RuCl(PPh₃) ₂] is a rare example of the loss of dihydrogen from a coordinated ligand.

Full text of DOI:10.1016/S0022-328X(97)00428-2

Ž
.
Journal of Organometallic Chemistry 551 1998 21–26
5
1
wž
/
ž / ž
/ x
The reaction between h -C7 H9 RuCl H PPh3 2 and dihydrogen
)
Brian E. Mann , Guo A. Sun
Department of Chemistry, The UniÕersity of Sheffield, Sheffield, S3 7HF, UK
Received 19 April 1997; received in revised form 10 June 1997
Abstract
5
3
wŽ
.
Ž
.2x
wŽ .2x
.
Ž
h -C7H9 RuCl PPh3
has been shown to react with hydrogen to give h -C7H11 RuCl PPh3 initially, and then
w
Ž .Ž . x w
Ž
x
Ž .
RuCl H PPh3 , Ru2H4Cl2 PPh3 , and unidentified compound s . This is a rare example of the hydrogenation of a coordinated
3
.4
ligand, where the ligand remains coordinated to the metal. It is suggested that the reverse reaction, involving the conversion of
3
5
wŽ
.
Ž
. x
wŽ . x
to h -C7H9 RuCl PPh3 is a rare example of the loss of dihydrogen from a coordinated ligand. q 1998
2
.
Ž
h -C7H11 RuCl PPh3
Elsevier Science S.A.
2
5
wŽ
.
Ž .Ž
. x
2
Keywords: h -C7 H9 RuCl H PPh3 ; Dihydrogen; Ligand
4
w
Ž .Ž
.
3x
Ž
.
w
2w
Ž
.
x
It has been previously shown that RuCl H PPh
Ph2 P CH2 6 PPh2 on reaction with h -cod MCl , M
w 3
Ž
w
Ä
Ž
.
2
3
reacts with cyclohepta-1,3-diene to give initially h -
s Rh, Ir, to give
trans-Ph P CH2 2CH5CH-
9 , and ReH7 P C6 H4 Me-
reacts with pentene to give Re h -
5
.
Ž
.
2 x
w
Ž
Ž
4
.
4
x
Ž . w x
Ä Ž
C
7 H
R u C l P P h
a n d th e n
h -
CH PPh2 MCl ,
4
1 1
3
3422x2
w
Ž
4
.
Ž
.
x w x
w
Ž .Ž
.
3x
.
C7 H9 RuCl PPh3
1 . Similarly, RuCl H PPh
2
w 3
Ž
.
Ä
Ž
.
342 x w
x
w
Ž
3
4
reacts with penta-1,4-diene to give initially h -
C5H8 H3 P C6 H4 Me-4
10 . When Ni h -1,5-
5
6
.
Ž
.
x
w
Ž
.
Ž
.
2 x
.Ž
.x
C5H9 RuCl PPh3
,
then
h -C5H7 RuCl PPh3
cod h -1,3,5-C8 H10 is treated with acetylacetone or
cyclopentadiene, the cyclooctatriene ligand is lost and
the 1,5-cod is converted to a 1,2,5-h3-C8 H13 ligand
11,12 .
The first stage of the reaction of RuCl H PPh3 is
2
5
w
Ž
.
Ž
.
x w x
2 . This was the
and finally h -C5H5 RuCl PPh3
2
first observation of the ring closure of a pentadienyl to a
cyclopentadienyl, although it had been earlier suggested
w
x
w x
as occurring in the mass spectrometer 3 . Subsequently,
the reaction was exploited to synthesise Ru h -2,4-
w
Ž .Ž
. x
3
5
w
Ž
the insertion of the diene into the Ru–H bond to give an
5
5
.Ž
3 xw x
.
x
w x
w
Ž
Me2 C 5 H 5 h -1,3-Me2 C 5 H 3
4 , Ru h -1,3-
allyl, and there are many examples of this process. For
5
5
4
.
2 x
w
x
w
Ž
.Ž
w
Ž
.Ž
.
3xq
Me2C5 H
4,5 , Os h -2,4-Me C5 H h -1,3-
example, RuH h -1,5-cod PMe2 Ph
reacts with
2 x w x5
w
Ž
.Ž
w
Ž
.
Ž
.
3xq
w x
13 .
5
5
3
.
w
Ž
.
Me2C5H35 4 , Os h -1,3-Me2C H3
4 , Ru h -
1,3-dienes to give Ru h -enyl Cl PMe2 Ph
2
Ž
5
5
.
.
x
w x 5w
C5 Me5 h -1,3-Me2C H
5 , Ru h -C5 Me55 h -
There is little information available to suggest a
mechanism for the second stage of the reaction. In the
.
5x w 3x
w
Ž
.Ž
5
1,2-dihydropentalenyl 5 , and Ru h -C5Me5 h -1,3-
But2C5H3 5 , albeit under much more forcing condi-
tions. Similar reactions are rare, but when cyclo-octa-
.
x w x
w x
original report 1 , it was suggested, by analogy with the
3
4
w
Ž
.Ž
.x
reaction of Co h -C8 H13 h -1,5-cod with cyclo-
3
w
Ž
.
x
Ž .
w x w Ž
octa-1,5-diene 7,8 , that the conversion of Ru h -
1,5-diene reacts with Re2 CO
at 2508C, 1 is formed
in a 5% yield 6 , and a similar ring closure has been
observed on heating 2 in the presence of cyclo-octa-
1,5-diene to give 3 quantitatively see Scheme 1 7,8 .
The dehydrogenation of a coordinated ligand, which
remains coordinated, is uncommon. Examples are the
dehydrogenation of the alkane chain of
10
5
w x
.
Ž
.
2 x
w
Ž
.
Ž
.2 x
in-
C7 H11 Cl PPh3
to Ru h -C7 H9 Cl PPh3
Ž .
volves the excess of diene acting as a hydrogen accep-
tor, but no evidence was presented 1 . In this paper, the
reaction is examined in greater detail. The initial stages
of the reaction have been previously investigated quanti-
tatively and it was shown that there are two reaction
Ž .
Ž
.
w
x
w x
w
x
pathways 14 . The mechanism which is dominant at
low diene concentration involves the loss of PPh3 to
)
w
Ž .Ž
.
x
which then reacts rapidly with
give RuCl H PPh
Corresponding author. E-mail: b.mann@sheffield.ac.uk.
3w 2
Ž
.
Ž
. x
3
1 Dedicated to Professor P.M. Maitlis on his 65th birthday.
the diene to give Ru h -enyl Cl PPh3 . A second
2
0022-328Xr98r$19.00 q 1998 Elsevier Science S.A. All rights reserved.

(
)
22
B.E. Mann, G.A. SunrJournal of Organometallic Chemistry 551 1998 21–26
and then very slowly decrease. Over the time, 10 to 560
3
w
Ž
.
Ž
.2 x
is
min, the concentration of h -C7 H11 RuCl PPh3
nearly constant, decreasing by only about 25%. The
5
w
Ž
h -
signals at
d
5.20 and
d
4.65 due to
3
4
w
Ž
.Ž
.x
Scheme 1. The reaction of Co h -C8 H13 h -1,5-cod with cyclo-
octa-1,5-diene.
.
Ž
. x
C7 H9 RuCl PPh3 increase rapidly initially. After ap-
2
5
w
Ž
proximately 100 min, the rate of formation of h -
2 x
.
Ž
.
C7 H9 RuCl PPh3
becomes approximately constant.
mechanism becomes significant at high diene concentra-
tion involving the direct attack of the diene on
It would be expected that the rate of formation of
5
3
w
Ž
.
Ž
.
x
wŽ
h -C7 H9 RuCl PPh
should be first order in h -
in the presence of a large excess
of cyclohepta-1,3-diene if the mechanism involves hy-
2
x 3
w
Ž .Ž
. x
.
Ž
.
C7 H11 RuCl PPh3
2
RuCl H PPh3 . Attempts to extend the kinetic inves-
3
tigation to the subsequent dehydrogenation failed due to
w
x
irreproducibility of the results 15 .
drogen transfer to the cyclohepta-1,3-diene. As the con-
3
w
Ž
.
Ž
.
2 x
centration of h -C7 H11 RuCl PPh3
decreases only
very slowly after its initial rapid formation, the slowing
5
wŽ
.
Ž
.2 x
1. Results and discussions
in the rate of formation of h -C7 H9 RuCl PPh3
must be due to poisoning. There are two possible
poisons, PPh3 and H2. PPh3 is initially liberated when
w
Ž .Ž
.
x
The reaction of RuCl H PPh3 with cycloheptadi-
ene has been previously examined. It was found that
x
is the first product which
then goes on to form Ru h -C7 H9 Cl PPh3
3
w
Ž .Ž .3x
the RuCl H PPh3 starting material is converted to
3
3
w
Ž
.
Ž
.
w
Ž
.
Ž
. x
2
Ru h -C7 H11 Cl PPh
h -C7 H11 RuCl PPh3 . However, when PPh3 is
3w2
Ž
.
Ž
.
x w x
1 . It
5
added, there is only a small effect on the rate. Attempts
were made to detect liberated hydrogen, but failed. This
is attributed to the small quantity of hydrogen produced
during a typical reaction.
2
was suggested that the reduction of the coordinated
3
5
Ž
.
Ž
.
ligand from h -C7 H11 to h -C7 H9 was achieved by
hydrogen transfer to the excess of cyclohepta-1,3-diene
present in solution producing cycloheptene. Attempts to
demonstrate the production of cycloheptene failed due
to the substantial impurity of cycloheptene in the com-
The effect of hydrogen on the reverse reaction was
investigated by passing hydrogen through a solution of
5
w
Ž
.
Ž
.
x
h -C7 H9 RuCl PPh3
in CD2Cl2 in an NMR tube.
2
w x
mercial cyloheptadiene being used in the reaction 1 .
When the reaction was carried out below y408C no
The reaction has now been repeated using purer cyclo-
hepta-1,3-diene, which was synthesised from cyclohep-
tene by allylic bromination, the isolation of the 3-
bromocycloheptene, and subsequent dehydrobromina-
tion to generate cyclohepta-1,3-diene which contained
reaction was observed. A slow reaction was observed at
y68C. The colour of the solution slowly changed from
5
w
Ž
.
Ž
.
x
the yellow of h -C7 H9 RuCl PPh3
to red and sub-
2
sequently to violet. The reaction was stopped at the red
stage by placing the NMR tube into a pre-cooled NMR
probe at y808C. The 31 P NMR spectrum showed there
w
x
less than 0.3% cycloheptene 16 . When this purer
cycloheptadiene was used the amount of cycloheptene
2
were two resonances at d 65.4 and d 33.8 with J 31 P,
Ž
formed, as detected using GLC and 1H NMR spec-
31
.
P s33 Hz. This is due to the formation of the allyl
5
w
Ž
troscopy, was less that 10% of the Ru h -
.
Ž
. x
C7 H9 Cl PPh3 formed. Hence, a mechanism involv-
2
ing hydrogen transfer from the coordinated allyl ligand
5
w
Ž
to cyclohepta-1,3-diene to give R u h -
and cycloheptene cannot be correct.
.
Ž
.
2 x
C7 H9 Cl PPh3
In order to try to understand the reaction further a
number of kinetic investigations were performed at
358C in CD2Cl2 and monitored by 1H NMR spec-
troscopy. A typical graph of the reaction kinetics is
shown in Fig. 1. It has been shown previously that there
w
Ž .Ž
.
x
is a rapid reaction between RuCl H PPh3
cloheptadiene to give initially
and cy-
R u h -
3w
Ž
3
.
Ž
. x
C7 H11 Cl PPh3 . This initial reaction subsequently
2
w
x
slows as it is poisoned by the liberated PPh3 14 .
Examination of a plot of the 1H NMR signals of
3
wŽ
.
Ž
. x
h -C7 H11 RuCl PPh3 at d 4.05 and d y7.8 and of
2
5
Fig. 1. The plot of intensity of some well-resolved hydrogen NMR
w
Ž
.
Ž
. x
the species, h -C7 H9 RuCl PPh3 at d 5.20 and d
2
3
5
wŽ
.
Ž
. x
wŽ . x
and h -C7 H9 RuCl PPh3 ,
2
.
Ž
signals of h -C7 H11 RuCl PPh3
2
4.65 against time, shows that the reaction goes fast at
1
monitored by 400 MHz 1H NMR spectroscopy vs. time in CD2Cl2 at
. x Ž
Ž
.
first then slows see Fig. 1 . The H NMR signals at d
w
Ž
. Ž
20 mg, 0.022 mmoles , cycloheptadiene 25
358C. RuClH PPh3
3
3
w
Ž
.
Ž
.2 x
4.05 and d y7.8 due to h -C7 H11 RuCl PPh3
.
Ž
.
Ž .
ml, 0.23 mmoles ; The allyl signals at d 4.05 I , d y7.8 e ,
dienyl signals at d 5.20 ` , d 4.65 ^ shown in the figure.
Ž
.
Ž .
initially increase rapidly during the first few minutes

(
)
B.E. Mann, G.A. SunrJournal of Organometallic Chemistry 551 1998 21–26
23
31
3
5
wŽ
.
Ž
. x
wŽ
.
Ž
. x
obtained in the reaction of h -C7 H9 RuCl PPh3 with hydrogen
2
Fig. 2. 162 MHz P NMR spectrum at 183 K of h -C7 H11 RuCl PPh3
in CD2Cl2.
2
1
3
w
Ž
.
Ž
.
x
complex, h -C7 H11 RuCl PPh3 . The species was
proton H NMR signal at d y18.52, a quartet at room
2
further confirmed by 1H NMR. A broad signal at d
y7.3 is typical of an agostic hydrogen resonance. The
phosphorus and proton chemical shifts are in good
temperature, is due to the three phosphines becoming
equivalent. This is in agreement with the literature 1 .
w x
w
Ž
x
Ru2Cl2 H4 PPh3.4 is characterised by comparison of
its 1H and 31 P NMR data with those published for
344 x w
agreement with the literature 1 . The 31 P NMR spec-
w x
3
wŽ
.
Ž
.
2 x
w
Ä
Ž
.
x
Ž
.
trum of h -C7 H11 RuCl PPh3
The signal at d 28.5 is due to OPPh3.
is shown in Fig. 2.
Ru2Cl2 H4 P tol
17 see Table 1 .
It can be seen from Table 1 that the proton and
On further shaking, and gentle warming, the red
phosphorus chemical shifts are similar, but not identical
probably due to the differences in the ligand and possi-
5
w
Ž
colour solution turned to purple and all the h -
.
Ž
.2 x
C 7 H 9 RuCl PPh 3
is hydrogenated to give
x w
bly the concentrations.
5
w
Ž .Ž
.
x w
Ž
.
x
w
Ž .Ž
.
3x
wŽ
RuCl H PPh3 , Ru2 H4Cl2 PPh3
17 , and an un-
The formation of RuCl H PPh3
from h -
Ž3
.
.
Ž
.
x
4
known species see Figs. 3 and 4 .
C7 H9 RuCl PPh3 requires the parallel formation of a
2
w
Ž .Ž
.
x
The species, RuCl H PPh3 , was characterised by
ruthenium species with one or no PPh3 ligands. The
NMR spectrum indeed showed that there were some
minor species produced. A 31 P NMR signal at d 46.0
3
31 P NMR, which consists of a triplet at d 95.0, and a
2
31
doublet at d 39.2 with
J
31 P, P s29 Hz. The
Ž .
1
w
Ž .Ž
. x
w
Ž
. x
4
Fig. 3. Partial of H 400 MHz NMR Spectrum of RuCl H PPh3 and Ru2Cl2 H4 PPh3 at y908C. The compounds formed by the reaction
3
5
wŽ . x
of h -C7 H9 RuCl PPh3 with H2.
2
.
Ž

(
)
24
B.E. Mann, G.A. SunrJournal of Organometallic Chemistry 551 1998 21–26
Table 1
31
Comparison of the 1H and P NMR parameters of Ru2Cl2 H4 PPh3 and Ru2Cl2 H4 P tol
Ä Ž . 4 x
3 4
w
Ž
. x
w
4
w
Ž
. x
w
Ä Ž . 4 x
Ru2Cl2 H4 P C6 H4 Me-4 in CD2Cl2 at y958C
3 4
Ru2Cl2 H4 PPh3 in CD2Cl2 at y908C
4
d 1P NMR data
d 1P NMR data
2
31
2
31
d 79.9 d, J 31P, P s37 Hz
d 74.2 d, J 31P, P s40 Hz
Ä
Ž
.
4
.
.
Ä
Ž
Ž
.
31
4
.
2
31
2
d 65.0 d, J 31P, P s17 Hz
d 58.3 d, J 31P, P s20 Hz
Ž
Ž
.
Ž
.
31
2
31
2
d 62.1 d, J 31P, P s35 Hz
d 56.3 dd, J 31P, P s40, 4 Hz
Ž
Ž
Ž
.
Ž
Ž
Ž
Ž
.
31
.
2
31
2
d 36.3 dd, J 31P, P s37, 17 Hz
d 33.5 dd, J 31P, P s40, 20 Hz
Ž
.
.
.
.
1H NMR data
1H NMR data
1
1
Ä
Ž31
.
4
Ä
Ž31
.
4
d y7.0 d, J P, H s72 Hz, 1H
d y9.2 d, J P, H s72 Hz, 1H
Ž
.
Ž
.
d y11.8 hump, 2H
1
d y10.6 hump, 2H
1
Ä
Ž31
d y16.4 t, J P, H s32 Hz, 1H
.
4
Ä
Ž31
4
d y19.4 t, J P, H s28 Hz, 1H
.
and 1H NMR signals at d y7.7 and d y9.8 were
tent with an initial endo addition of the deuterium to
5
w
Ž
.
Ž
.2 x
observed, which could be attributed to the formation of
h -C7 H9 RuCl PPh3 followed by a dynamic pro-
a polyhydride species. Unfortunately, this species was
cess where the ruthenium moves its agostic interaction
from one side to the other of the cycloheptadienyl
5
Ž
.
not identified. The organic moiety, h -C7 H9 , was
converted into cycloheptene, which gives 1H NMR
signals at d 5.80 t , d 2.02 m , d 1.65 m , and d
1.50 m partially obscured and cycloheptane which
shows a singlet at d 1.50.
ligand see Scheme 2 . It has been previously demon-
strated that there is an equilibrium where the ruthenium
moves its agostic bonding from one side of the allyl to
Ž
.
Ž .
Ž .
Ž .
Ž . Ž
.
w x
the other 1 .
To further investigate the hydrogenation site, D2 was
used. D2 was generated by using the reaction of sodium
metal in freshly distilled THF containing ca. 2% deu-
In the case of the partially deuterated cycloheptenyl
ring, this results in the ruthenium moving between an
agostic deuterium and an agostic hydrogen and leads to
a mixture of compounds with the ruthenium attached to
an agostic deuterium or an agostic hydrogen in approxi-
terium oxide.
5
wŽ
Dideuterium was passed through a solution of h -
.
Ž
.
2 x
Ž .
mately equal quantities see Scheme 2 . The signals at d
2
C7 H9 RuCl PPh3
in CD2Cl2 at y68C. During the
31
Ž31
.
period of bubbling, the solution colour changed from
light yellow to fresh red in several minutes. The bub-
bling was stopped and the sample was put into an ethyl
acetate slush bath at y848C to stop the reaction. The
31 P NMR spectrum at y408C showed two sets of
doublets of doublets indicating the formation of the allyl
64.8 and 33.4, J P, P s33 Hz, are tentatively as-
signed to the species with the agostic deuterium, while
the signals at d 65.2 and 33.6 are assigned to the
species with the agostic hydrogen. The difference in
chemical shifts is an example of the secondary isotope
effect.
5
Ž
.
wŽ
.
Ž
.
x
intermediates see Fig. 5 .
The reaction of h -C7 H9 RuCl PPh3
illustrated in Scheme 3.
with H2 is
2
The expansion 31 P NMR spectrum clearly shows two
2
5
w
Ž
pairs of doublets. The H NMR spectrum showed sig-
The mechanism of the reaction of
h -
.
Ž
.
2 x
nals at d y7.8, 1.3 and 2.0. The signal at d y7.8 is
C7 H9 RuCl PPh3
with dihydrogen is unknown.
There are two reasonable mechanisms. It is known that
3
w
Ž
attributed to the agostic deuterium in
h -
5
.
Ž
.
x
w
Ž
. Ž
h -C5 R 5 RuCl dippe , R s H, Me, dippe s
5
.x
C7 H9 D2 RuCl PPh3 . These observations are consis-
2
Pr2i PCH2CH2 PPr2i , reacts with H2 to give h -
w
Ž
Ž
5
.
Ž
.
xq
w
x
w
C5 R 5 RuH 2 dippe
18 . Alternatively,
h -
i
.
Ž
.x
C5Me5 RuCl PPr2 Ph reacts with hydrogen to give
h -C5Me5 RuCl H PPr2 Ph 19 Hence, it would
be reasonable to suggest that dihydrogen reacts with
5
i
w
Ž
.
Ž . Ž
.
x w
x
2
5
5
w
Ž
.
Ž
.
x
wŽ
.
2
h -C7 H9 RuCl PPh
to give either h -C7 H9 -
Ž
.
2 xq
3w 2
Ž
.
Ž
.Ž
.
xq
.
5
RuH2 PPh3
or h -C7 H9 RuCl H2 PPh3
There is circumstantial evidence for the latter route.
5
5
w
Ž
.
Ž
.
x
wŽ
h -C7 H9 RuCl dppe was prepared by heating h -
.
Ž
.
x
C7 H9 RuCl PPh3
with an excess of dppe. Subse-
quent treatment of h -C7 H9 RuCl dppe with dihy-
2 w
Ž
.
Ž
.x
5
Fig. 4. 162 MHz 31 P NMR spectrum of RuCl H PPh3
and
Ž .Ž .3x
w
2 These compounds could be either dihydrogen or dihydride com-
plexes.
5
w
Ž
.4 x
wŽ
Ru2Cl2 H4 PPh3
at y908C formed by the reaction of h -
.
Ž
. x
C7 H9 RuCl PPh3 with H2.
2

(
)
B.E. Mann, G.A. SunrJournal of Organometallic Chemistry 551 1998 21–26
25
Fig. 5. 162 MHz 31 P NMR spectrum of h -C7 H9 RuCl PPh3.2 recorded at y408C after reaction with D2 at y68C. a The complete spectrum;
5
wŽ
wŽ
.
Ž
x
Ž .
3
Ž .
.
Ž
. x.
b the expansion of the signals due to h -C7 H9 D2 RuCl PPh3
.
2
Ž
.
drogen gave no reaction even after treating for 1 h at
908C. This observation gives support for the need for
PR3 dissociation prior to reaction with dihydrogen. A
pyridine showed that for P C6 H4 Me-4 there are two
3
pathways for the reaction, an associative and a dissocia-
tive mechanism, while for pyridine, the reaction was
w
x
determination of the kinetics of PPh3 displacement from
exclusively dissociative 20 . In both cases, the reaction
proceeded at a steady rate at y298C.
5
w
Ž
.
Ž
.
2 x
Ž
.
h -C7 H9 RuCl PPh3
by P C6 H4 Me-4 and by
3
If the first step of the reaction is the loss of PPh3
followed by reaction with hydrogen to give h -
5
w
Ž
3
.
Ž
.Ž .x
C7 H9 RuCl H2 PPh3 ,
then the formation of
w
Ž .Ž
. x
3
RuCl H PPh3 is readily explained by the reaction of
w
Ž .Ž . x
an intermediate such as RuCl H PPh3 with the free
2
PPh3 in solution. As the starting compound contains
only two PPh3 ligands per ruthenium, the formation of
5
wŽ
.
Ž
. x
Scheme 2. The reaction of h -C7 H9 RuCl PPh3
with D2 to give
2
a thermal equilibrium Ru–D–C and Ru–H–C agostic allyl com-
w
Ž .Ž
. x
RuCl H PPh3 requires the formation of a ruthenium
3
plexes.
species with one or no PPh3 ligand per ruthenium.
There are additional hydride signals observed at d
y7.7 and y9.9 due to an unidentified ruthenium hy-
dride. In addition there are a number of weak 31 P NMR
signals observed.
5
3
w
Ž
.
Ž
.
2 x
wŽ
The reduction of h -C7 H9 RuCl PPh3
to h -
.2 x
C7 H11 RuCl PPh3 is an example of the very rare
.
Ž
reduction of a coordinated ligand where the ligand
3 This compounds could be either a dihydrogen or dihydride
complex.
5
wŽ
.
Ž
.2 x
Scheme 3. The reaction of h -C7 H9 RuCl PPh3
gen.
with dihydro-

(
)
26
B.E. Mann, G.A. SunrJournal of Organometallic Chemistry 551 1998 21–26
remains coordinated to the metal. This has been ob-
The sample was characterized by 31 P NMR spec-
troscopy, two signals at d 73.8 and 69.1. The product is
quite stable in solution. When exposed to air for two
days, the yellow coloured solution slowly changed to
dark green.
5
w
Ž
.
x
served for h -C5H5 2 Ni , which has been reduced to
3
5
w
Ž
.Ž
.
x w
x
h -C5H7 h -C5H5 Ni 21 . There have been other
w
x
w x
examples involving zirconium 22 , chromium 23 ,
molybdenum 24 , rhenium 25 , iron 26 and cobalt
27 . There are numerous examples of ligand reduction
resulting in the loss of the ligand. The most relevant
w
x
w
x
w x
w
x
Acknowledgements
example of hydride transfer to a coordinated ligand
5
w
Ž
followed by loss, is the example of
h -
xq
GAS thanks the University of Sheffield for the provi-
sion of a studentship.
.
Ž
.Ž
.
C5H5 RuH2 CO PPh3
.
clopentadiene is lost and RuH CO CNMe PPh3
in acetonitrile where cy-
.Ž . Ž
xq
is formed 28,29 . A similar reaction is observed when
w
Ž
3
w
x
5
w
Ž
.
Ž
.
x
h -C5H5 Mo CO H reacts with acetonitrile to give
3 w
Ž
. Ž
.
x w
x
30 .
References
cyclopentadiene and Mo CO NCMe
3
3
w x
1
M. Grassi, B.E. Mann, P. Manning, C.M. Spencer, J. Organomet.
Ž
.
Chem. 307 1986 C55.
2. Experimental
w x
2
B.E. Mann, P.W. Manning, C.M. Spencer, J. Organomet. Chem.
Ž
.
312 1986 C64.
1H, 13C, and 31 P NMR spectra were recorded on a
Bruker WH400 spectrometer. The GLC analysis was
performed using a Perkin-Elmer 8700 GC with a
Chrompak CPSIL5 30 m column.
w x
Ž .
3
L. Stahl, R.D. Ernst, Organometallics 2 1983 1229.
R.U. Kirss, Organometallics 11 1992 497.
w x
Ž
.
4
w x
5
R.U. Kirss, A. Quazi, C.H. Lake, M.R. Churchill,
Ž
.
Organometallics 13 1993 4145.
w x
6
K.K. Joshi, R.H.B. Mais, F. Nyman, P.G. Owston, A.M. Wood,
w
x
The syntheses of cycloheptadiene 16 and
Ž
.
J. Chem. Soc. A 1968 318.
w
Ž .Ž
.
x w
x
RuCl H PPh3
31 have been described previously.
w x
7
H. Lehmkuhl, W. Leuchte, E. Janssen, J. Organomet. Chem. 30
3
Ž
.
1971 407.
5
[(
)
(
)2 ]
2.1. Preparation of h -C7 H9 RuCl PPh3
w x
8
Ž
.
S. Otsuka, T. Taketomi, J. Chem. Soc., Dalton Trans. 1972
1879.
Ž
.
Ž
RuCl3 PnH2O 1.2 g, 0.0048 moles in dioxan 200
w x
Ž .
P.W. Clark, J. Organomet. Chem. 110 1976 C13.
10 D. Baudry, M. Ephritikhine, H. Felkin, J. Zakrzewski, J. Chem.
9
x
.
w
ml was refluxed for 5 min. After cooling to room
temperature, triphenylphosphine 4.8 g, 0.018 moles
was added to the solution. The resulting solution was
stirred for two days, and the dark brown solution
ch an g ed to lig h t g reen y ello w . 1 ,8 -
Ž
.
Soc., Chem. Commun. 1982 1235.
Ž
.
w
w
w
x
Ž
.
11 O.S. Mills, E.F. Paulus, Chem. Commun. 1966 738.
x
Ž
.
12 W. Barnett, J. Organomet. Chem. 21 1970 477.
x
13 T.V. Ashworth, A.A. Chalmers, E. Meintjies, H. Oosthuizen, E.
Ž
.
Singleton, J. Organomet. Chem. 276 1984 C19.
3
w
x
Ž
.
w
w
w
w
w
w
x
Ž
.
Diazabicyclo 5.4.0 undec-7-ene 2.6 cm was injected
into the solution and the solution was refluxed with
hydrogen bubbling through it for 1 h, when a violet
14 G. Alibrandi, B.E. Mann, J. Chem. Soc., Dalton Trans. 1994
951.
x
15 G. Alibrandi, B.E. Mann, P.W. Manning, G.A. Sun, unpub-
lished results.
coloured solution was formed. Degassed cyclohepta-
x
16 C.C. Arthur, A.L. Theodor, W.W. Geoffrey, J. Am. Chem. Soc.
3
Ž
.
triene 1.8 cm , 1.58 g, 0.017 moles was added, and
the solution refluxed for 40 min. The solution was then
allowed to cool to room temperature. A white grey solid
precipitated and was filtered off. The solution was
concentrated until fine bright yellow crystals separated.
After recrystallisation either from THF or dioxan 20
cm , it was filtered and washed with 4 cm of 40–608C
petroleum ether, and dried on the vacuum line. Yield:
3.54 g, 81%. Purity: calc. % : C, 68.47; H, 5.21; Cl,
4.7; anal: C, 68.05; H, 5.16, Cl, 4.82.
Ž
.
79 1957 6287.
x
17 T.W. Dekleva, I.S. Thorburn, B.R. James, Inorg. Chim. Acta
Ž
.
100 1985 49.
x
18 I. de los Rıos, M.J. Tenorio, J. Padilla, M.C. Puerta, P. Valerga,
´
Ž
.
Organometallics 15 1996 4565.
x
Ž
.
19 T.D. Johnson, P.S. Coan, K.G. Caulton, Inorg. Chem. 32 1993
Ž
4594.
3
3
.
w
w
x
20 G.A. Sun, PhD Thesis, Sheffield University, 1996.
x
21 K.W. Barnett, F.D. Mango, C.A. Reilly, J. Am. Chem. Soc. 91
Ž
.
1969 3387.
Ž
.
w
x
Ž
.
22 R.M. Waymouth, F. Bangerter, P. Pino, Inorg. Chem. 27 1988
758.
w
w
w
w
w
x
Ž
.
23 E.O. Fischer, J. Muller, J. Organomet. Chem. 1 1964 464.
¨
5
[(
)
(
)]
2.2. Preparation of h -C7 H9 RuCl DPPE in toluene
x
Ž
.
.
24 R.B. King, F.G.A. Stone, J. Am. Chem. Soc. 82 1960 4557.
x
Ž
25 M.L.H. Green, G. Wilkinson, J. Chem. Soc. 1958 4314.
Ž
.
A solution of DPPE 107.1 mg in degassed toluene
x
Ž
.
26 E.O. Fischer, J. Muller, J. Organomet. Chem. 1 1964 464.
¨
10 cm3 was added to solution of
2 x
h -
200 mg, 0.27 mmoles in toluene
5 cm in a nitrogen filled Schlenk tube. The solution
was refluxed for 1 h then was cooled to room tempera-
5
Ž
.
wŽ
x
27 A. Nakamura, N. Hagihara, J. Chem. Soc. Jpn., Pure Chem.
.
Ž
.
Ž
.
Ž
.
C7 H9 3RuCl PPh3
Sect. 82 1961 1392.
w
x
Ž
.
28 O.B. Ryan, M. Tilset, V.D. Parker, Organometallics 10 1991
Ž
.
298.
w
w
x
x
Ž
.
29 O.B. Ryan, M. Tilset, J. Am. Chem. Soc. 113 1991 9554.
30 G.J. Kubas, G. Kiss, C.D. Hoff, Organometallics 10 1991
Ž
ture, and degassed petroleum ether b.p. range 45–658C;
Ž
.
2 cm3 was slowly added for crystallisation. The yield
.
2870.
w
x
Ž
.
of the crude product was 0.16 g.
31 R.A. Schunn, E.R. Wonchoba, Inorg. Synth. 13 1972 131.