Use of the seven-coordinate complexes [MXY(CO)3(NCMe)2] (M = Mo or W; X, Y = halide) and their derivatives in homogeneous catalysis

Article abstract of DOI:10.1016/S1381-1169(00)00170-9

The seven-coordinate halocarbonyl complexes, [MXY(CO)₃(NCMe)₂] (M = Mo or W; X, Y = halide) and their derivatives have been investigated in several types of homogeneous catalytic reactions. These include, the alkene metathesis polymerisation of norbornadiene using either, [MX₂(CO)₃(NCMe)₂] (M = Mo or W;X = Br or I), [MI₂(CO)₃(L'-P, P')] {M=Mo or W; L' = MeC(CH₂PPh₂)₃} or [MXY(CO)L or L'-P, P')(η²-RC₂R')] {X,Y = Cl, Br or I; L = PhP(CH₂CH₂PPh₂)₂; R,R' = Me, Ph}. The isolation and characterisation of a key intermediate, [WI₂(CO)₂(η⁴-nbd)] (1) (nbd = norbornadiene) is also described. The development of water soluble polymerisation catalysts using water-solubilising pyridine ligands, and the biphasic polymerisation of styrene using [WI₂(CO)₃(NC₅H₄CO₂Na-4)₂], ZrCl₄, sodium lauryl sulphate and sodium hydrogen phosphate is also discussed. The room temperature polymerisation of phenylacetylene using [WX₂(CO)₃(NCMe)₂] (X = Cl, I), [WI₂(CO)₃(NCMe)L] (L = PPh₃, AsPh₃) or b [WBr₂(CO)(NCMe)(η²-HC₂Ph)₂] (4) is also described, and a mechanism is proposed for these polymerisation reactions. (C) 2000 Elsevier Science B.V.

Full text of DOI:10.1016/S1381-1169(00)00170-9

Ž
.
Journal of Molecular Catalysis A: Chemical 159 2000 51–62
www.elsevier.comrlocatermolcata
w
ž / ž
/ x
Use of the seven-coordinate complexes MXY CO NCMe
3
2
ž
/
MsMo or W; X, Yshalide and their derivatives in
homogeneous catalysis
Mutlaq Al-Jahdali a, Paul K. Baker a,), Aidan J. Lavery b, Margaret M. Meehan a,
David J. Muldoon a
Department of Chemistry, UniÕersity of Wales, Bangor, Gwynedd, LL57 2UW, Wales, UK
a
b
ZENECA Specialties, PO Box 42, Hexagon House, Blackley, Manchester, M9 3DA UK
Abstract
w
Ž
. Ž
. x Ž
.
The seven-coordinate halocarbonyl complexes, MXY CO NCMe
MsMo or W; X, Yshalide and their
3
2
derivatives have been investigated in several types of homogeneous catalytic reactions. These include, the alkene metathesis
X
w
Ž
. Ž
. x Ž
. w
Ž
. Ž
X.x
polymerisation of norbornadiene using either, MX2 CO NCMe
MsMo or W;XsBr or I , MI2 CO L-P, P
3
2
3
X
X
Ä
Ž
.34
w
Ž
.Ž
X.Ž
X .x
2
h -RC2R
Ä
Ms Mo or W; L s MeC CH2PPh2
or MXY CO L or L-P,
P
X,Y s Cl, Br or I; L s
X
4
Ž
.
4
w
Ž
. Ž
.x Ž .
PhP CH2CH2PPh2 2; R,R sMe, Ph . The isolation and characterisation of a key intermediate, WI2 CO h -nbd
1
2
Ž
.
nbdsnorbornadiene is also described. The development of water soluble polymerisation catalysts using water-solubilising
w
Ž
. Ž . x
pyridine ligands, and the biphasic polymerisation of styrene using WI2 CO NC5H4CO2Na-4 , ZrCl4, sodium lauryl
3
2
sulphate and sodium hydrogen phosphate is also discussed. The room temperature polymerisation of phenylacetylene using
2
w
Ž
. Ž
. x Ž
. w
Ž
. Ž
. x Ž
.
w
Ž
.Ž
.Ž
. x Ž .
XsCl, I , WI2 CO NCMe L LsPPh3, AsPh3 or WBr2 CO NCMe h -HC2Ph 4 is
2
WX2 CO NCMe
3
2
3
also described, and a mechanism is proposed for these polymerisation reactions. q 2000 Elsevier Science B.V. All rights
reserved.
Ž .
Ž .
Keywords: Molybdenum II ; Tungsten II complexes; Halocarbonyl; Polymerisation; Metathesis; Water soluble biphasic catalysts;
Phenylacetylene polymerisation
w Ž
.
3
1. Introduction
of the zero-valent complexes fac- M CO -
Ž
w
.3x Ž
NCMe
prepared in situ by refluxing
w x
In 1986, we described the synthesis 1 and
characterisation, including by X-ray crystallog-
Ž
.
x
w x.
M CO in acetonitrile 4 with X2 at 08C. In
1994 5 , we described an improved method of
6
w x
Ž
w x w x.
raphy MsMo, XsI 2 ; MsW, XsI 3
w
Ž
.
3
preparing the dibromo complexes, MBr2 CO -
w
Ž
.
3
of the seven-coordinate complexes MX2 CO -
Ž
w
.
x
NCMe by carrying out the oxidation of fac-
M CO NCMe with bromine at y788C. We
have also investigated the oxidation of fac-
Ž
. 2Ž
. x
Ž
.
2 x
Ž
.
NCMe
MsMo, W; XsBr, I . These
3
3
Ž .
seven-coordinate molybdenum II and tung-
Ž .
sten II complexes were prepared by oxidation
w
Ž
. Ž
.
3x
Ž
w x
.
Mo CO NCMe
prepared in situ 4 with a
3
Ž
variety of other oxidising agents, XY XYsICl,
w x w x w x w x.
9 to afford the
)
6 , IBr 7 , GeCl4 8 , SnCl4
Corresponding author. Fax: q44-012-48-37-0528.
1381-1169r00r$ - see front matter q 2000 Elsevier Science B.V. All rights reserved.
Ž
.
PII: S1381-1169 00 00170-9

(
)
52
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
. w Ž
.
3
mixed-halogen seven-coordinate complexes,
1 . The norbornene intermediates, MX2 CO -
2
w
Ž
. Ž
.
2 x
Ž
Ž
.x
MoXY CO NCMe
XsCl, YsI; Xs
L h -nbe undergo a 2,3-hydrogen shift to give
3
w
x
Br, YsI; XsCl, YsGeCl3; XsCl, Ys
a metal-carbene initiator 13 .
In view of these observations 12,13 , we
decided to study the catalytic activity of our
.
w
x
SnCl3 . Over the years, we have been studying
the chemistry of these MXY CO NCMe
highly versatile seven-coordinate complexes,
w
Ž
. Ž
.2 x
3
w
Ž
. Ž
.
2 x
Ž
.
MX2 CO NCMe
MsMo, W; XsBr, I
3
and we have prepared and characterised over
complexes and their derivatives. The complex
y
3
w
x
w
Ž
. Ž
.2 x Ž
2000 derivatives from these complexes 10,11 .
In this article, we describe some of the applica-
MoI2 CO NCMe
9.8421 = 10
mol
3
3
dmy was suspended in toluene and a 200-fold
.
y
3
w
Ž
. Ž
.
x
Ž . Ž
excess of norbornadiene nbd , 2.1 mol dm
.
tions of the complexes MXY CO NCMe
,
3
2
and their derivatives in homogeneous catalysis.
was added. The reaction was stirred at room
temperature for 24 h and followed by gas chro-
matography. The solution was monitored at reg-
ular intervals to measure the concentration of
nbd, which remained constant throughout the
experiment, suggesting that none of the nbd had
polymerised. The reaction was repeated at 358C,
408C and 508C and similar results were ob-
2. Results and discussion
The purpose of this article is to show the
versatility of the seven-coordinate complexes,
w
Ž
. Ž
.2 x
MXY CO NCMe and their derivatives in
3
Ž
.
different types of catalytic reactions, which will
tained, i.e. no poly norbornadiene was formed.
The metathesis polymerisation of nbd at room
temperature was also attempted in thf, benzene
and CHCl3, but again no catalytic activity was
be described in Sections 2.1–2.5.
2.1. Metathesis polymerisation of norbornadi-
[
(
) (
) ] (
w
Ž
.
ene using MX2 CO 3 NCMe 2 MsMo, W;
observed. The tungsten complexes WI2 CO -
3
t
)
Ž
.
2 x Ž .
XsBr, I
NCR
RsBu , Ph were also found to be
inactive single component catalysts for the
metathesis of nbd in both toluene and benzene
at room temperature.
w
x
In 1985, Bencze and Kraut-Vass 12 showed
that the seven-coordinate dihalo-tricarbonyl
w
Ž
.
x
Ž
w x
complexes MX2 CO L2 MsMo, W; Xs
3
.
Cl, Br; LsPPh3, AsPh3 are single component
catalysts for the ring-opening metathesis poly-
merisation of norbornene and norbornadiene.
They found that the tungsten complexes were
superior to their molybdenum analogues, and
the AsPh3 complexes were better catalysts than
their PPh3 analogues. The tungsten complexes,
excellent catalytic activity. We studied the
metathesis polymerisation of nbd with MI2-
2 x
Ž
Ž
MsMo, RsMe; MsW, R
sMe, Bu , Ph in the presence of a co-catalyst,
ZrCl4 or ‘‘AlCl3’’. A mixture of MoI2 CO -
Ž
Ž
NCMe , ZrCl4 and nbd molar ratio 1:3:200
.
see experimental Section 4.2 were prepared.
After stirring the mixture for 10 min, the vis-
cous reaction mixture was poured into an excess
of methanol to give a white polymer, poly-
w
Ž
. Ž
.
x
WX2 CO AsPh3 2 showed considerable ac-
3
tivity in benzene at 353 K. The rate of poly-
w
Ž
. Ž
. x
merisation of WCl2 CO AsPh3 2 was 1.2"
3
0.1=104 mol dmy sy for norbornene con-
centrations of 0.25–3.0 mol dmy3, and that the
rate was found to be independent of monomer
concentration. They also found that the activity
was retained in the presence of air and moisture.
3
1
Ž
w
x
They proved 12 , that the rate-determining step
in these reactions was loss of L, which was
Ž
followed by alkene coordination see Scheme
Scheme 1.

(
)
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
53
Similar reactions of the tungsten complexes,
t
w
Ž
. Ž
.
2 x
Ž
.
WI2 CO NCR
RsMe, Bu , Ph also
3
rapidly metathesised nbd at room temperature in
Ž
toluene in the presence of ZrCl4 molar ratio
w
Ž
. Ž
.
x
.
1:3:1000; WI2 CO NCR :ZrCl4:nbd . Very
similar activity and results were obtained when
3
2
using ‘‘AlCl3’’ as a co-catalyst. The polymers
Fig. 2. The 13C NMR environments for poly norbornadiene .
were characterised by 1H NMR CDCl3,q
Ž
.
Ž
.
258C , and had two quintets at ds1.24 and
Ž
.
2.41 ppm due to Ha and Hb see Fig. 1. , a
quartet at ds3.57 ppm due to Hc, and a
w
Ž
.
3
nbd. To a toluene solution of MoBr2 CO -
Ž
.
doublet and singlet at 5.23 ppm Hd and 5.56
y
2
NCMe , 1.55=10 mol dmy3 , was added
Ž
.
x
Ž
.
ppm He , respectively. The 13C NMR spectra
2
Ž
.
a 200-fold excess of nbd, 3.09 mol dmy at
room temperature. Within minutes, the solution
had become too viscous to stir, and a high yield
3
Ž
.
CDCl3,q258C generally had resonances at
ds29.86 ppm and 30.77 ppm due to the cyclic
Ž
.
carbons C1 and C2 atoms see Fig. 2 , and
resonances at ds127.84 and 128.31 ppm due
to C3 and C4, respectively. Due to the poor
resolution of these spectra, it was difficult to
assign whether the polymer is all cis-, all trans-
or cisrtrans in our studies.
Ž
.
of poly norbornadiene was obtained, which was
very difficult to separate from the molybdenum
catalyst. H and 13C NMR data confirmed the
1
Ž
.
formation of poly norbornadiene . Similar re-
sults were obtained for the metathesis polymeri-
w
Ž
.
sation using the tungsten complex, WBr2 CO -
NCMe 5 , and the molybdenum complexes
. x Ž
MoBr2 CO NCMe L L s PPh3, AsPh3,
3
w
x
Hughes 14 , has shown that the catalytic
activity of the molybdenum nitrosyl complexes,
Ž
. x w x
w
Ž2 . Ž
3
w
Ž
.
x
MoX2 NO L2 was very dependent on the
2
.
w x
SbPh3 5 .
nature of X and L. It was found that the activity
increased along the series, AsPh3 -4-EtC5H4N
-OPPh3, and I-Br-Cl. From these observa-
We can conclude from these preliminary
studies of the metathesis polymerisation of nbd
using MX2 CO NCMe L , that the dibromo-
complexes are room temperature single compo-
nent polymerisation catalysts, whereas the di-
iodo-complexes must have a co-catalyst such as
ZrCl4 or ‘‘AlCl3’’ in order to initiate polymeri-
sation.
w
Ž
. Ž
. x
3
w
x
tions 14 , and those of Bencze and Kraut-Vass
w
x
w x
12 and Bencze et al. 13 , the lack of activity
w
Ž
. Ž
. x
of MoI2 CO NCMe , as a single compo-
nent nbd metathesis polymerisation catalyst, may
3
2
be due to the halide. The analogous dibromo-
w
Ž
. Ž
.2 x Ž
complexes, MBr2 CO NCMe
M s Mo,
5 were studied as single component cata-
lysts for the ring-opening polymerisation of
3
.
W
w x
2.2. Preparation and characterisation of the
diene complexes WI2 CO 2 h -diene
4
[
(
) (
)] (
diene
)
snbd, isoprene
A number of diene dicarbonyl complexes of
4
w
Ž
. Ž
.
x
w
x
the type W Br2 CO
h -nbd
15 ,
. Ž 2
.
x
w
x
4
w
w
w
w
Ž
Ž
. Ž
W B r S C F54 C O
h -n b d
X s Br,
1 6 ,
.6 Ž
.
x
.Ž
2 Ž
.
w
x
MoX 2 CO h -nbd
I
17 ,
4
Ž
Ž
. Ž 2
.
xq
w
x
WBr CO terpyridine h -nbd
18 and
2
4
.Ž
. Ž
.x w x
WCl SnCl3 CO h -nbd 19 have been de-
scribed. In view of Bencze and Kraut-Vass’s
3
Fig. 1. The 1H NMR proton environments in poly norbornadiene .
w
x
Ž
.
12 , observation that the rate determining step

(
)
54
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
.
x
in the metathesis polymerisation of nbd in-
nbd , and it does have the geometry suggested
above and shown in Fig. 3.
volved initial formation of an h2-alkene com-
Ž
.
plex see Scheme 1 . It may be that after initial
A similar reaction of equimolar amounts of
2
w
w
Ž
. Ž
.2 x
formation of our h -nbd complexes, MBr2-
WI2 CO NCMe
and isoprene in refluxing
hexane for 5 h was not successful. However,
3
2
Ž
. Ž
.Ž
.x
CO NCMe h -nbd they could either un-
3
w
Ž
. Ž
. x
dergo a 2,3-hydrogen shift or coordination of
the other alkene unit on nbd to give MBr2 CO -
h -nbd 15,17 , which has been structurally
refluxing WI2 CO NCMe with a slight ex-
3
2
w
Ž
.
cess of isoprene in refluxing CHCl3 for 24 h,
2
4
Ž
.
x w
x
gives the new black dicarbonyl product
4
w
x
w
Ž
. Ž
.
x
Ž .
characterised for MsW 20 .
WI2 CO h -isoprene
2 , which has been
2
Ž
In view of the lack of catalytic activity of
fully characterised see experimental Section
4.5 . Since the IR spectral properties of 2 are
similar to WI2 CO h -nbd , it will very
likely have a similar structure as shown for the
w
Ž
. Ž
.2 x
.
Ž .
WI2 CO NCMe
towards the polymerisa-
tion of nbd, we decided to try to prepare the
3
4
w
Ž
. Ž
.x
2
w
Ž
.
new six-coordinate nbd complex, WI2 CO -
h -nbd . Refluxing the seven-coordinate com-
2
4
Ž
.x
Ž .
nbd complex in Fig. 3. The coordinated nbd 1
w
Ž
. Ž
.2 x
Ž .
plex WI2 CO NCMe in hexane for 3 h
and isoprene 2 , have their proton resonance’s
3
with a slight excess of nbd eventually gave a
shifted slightly downfield as expected. Complex
Ž .
Ž .
dark green solid, which was recrystallised from
1 is dark green and complex 2 is dark brown.
Both complexes are relatively air-stable in the
solid state, but air-sensitive in solution. Com-
CH2Cl2rEt2O at y178C to afford the new
4
w
Ž
. Ž
.
x
Ž .
diiodo diene complex WI2 CO h -nbd
1
2
Ž .
Ž .
in17% yield. Complex 1 was characterised by
elemental analysis C, H and N , IR and H
NMR spectroscopy see experimental Section
plex 1 was soluble in chlorinated solvents, but
only slightly soluble in hydrocarbon solvents.
Complex 2 was much less soluble in these
solvents, but more soluble in methanol.
1
Ž
.
Ž
Ž .
.
Ž
.
4.4 . Since the IR CHCl3 spectrum has car-
bonyl bands at 2057 w , 1989 s cm 1, very
y
Ž .
Ž .
A summary of the reactions of nbd with
WI2 CO NCMe is given in Scheme 2.
4
w
Ž
. Ž
.x
w
Ž
. Ž
. x
similar to WBr2 CO h -nbd , which has been
structurally characterised 20 , it is likely 1
2
3
2
w
x
Ž .
Ž
.
will have a similar structure see Fig. 3 . The
2.3. Nbd metathesis polymerisation using,
X
[
(
) (
X)] [
) (
(
)
(
)(
X)(
)(
strong asymmetric band at 1989 cmy is as-
1
2
MI2 CO 3 L-P, P
,
MXY CO L-P, P h -
X
X
Ž
X)] [
(
X)] [
(
signed to the trans-carbonyl ligands see Fig.
.
RC2 R , MI2 CO 3 L-P, P , MXY CO L-P,
X)(
X)]
y
1
2
3 , whereas the weak band at 2057 cm is due
P
h -RC2 R
X s Cl, Br, I; L s
X
(
(
)
;
to the symmetric stretch activated by the distor-
PPh CH2CH2 PPh2 2 ; L s MeC CH2 PPh2 3
YsI; RsR sMe, Ph; RsMe, R sPh
X
X
w
x
)
tion from octahedral geometry 20 . It should be
w
x
Ž
noted that we have very recently 21 obtained
4
w
. Ž
the X-ray crystal structure of WI2 CO h -
Having described the catalytic activity of
WX2 CO NCMe
for the polymerisation of nbd in Sections 2.1
2
w
Ž
. Ž
.
2 x
Ž
.
MsMo, W; XsBr, I
3
and 2.2, herein we compare the activity of a
X
w
Ž
. Ž
series of complexes of the type MI2 CO L-P,
3
X.Ž
X
X
2
.
x
Ž
. w Ž .Ž
MsMo or W , MXY CO L-P, P h -
X X
2
P
.
x
w
Ž
.Ž
X.Ž
.x
RC2R and MXY CO L-P, P h -RC2R
Ä
Ž
X s Cl, Br, I, Y s I; L s L s PPh CH2-
X
X
.
Ž
.
CH2 PPh2 2; L sMeC CH2 PPh2 ; RsR s
3
X
4
Me, Ph; RsMe, R sPh towards the ring-
opening polymerisation of nbd.
w
x
In 1988 22 , we described the synthesis and
4
Ž
.
w
Ž
. Ž
.x Ž .
characterisation of a series of bis alkyne com-
Fig. 3. Proposed structure of WI2 CO h -nbd 1 .
2

(
)
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
55
scribed in Sections 2.1 and 2.2, i.e. that the
complexes with the more electronegative halide
ligands are the most active towards the poly-
merisation of nbd. The polymers were charac-
1
terised by H and 13C NMR spectroscopy, but
again the resolution was not good enough to be
able to be sure of the cis:trans isomer ratios
within the polymers.
Scheme 2.
2.4. Emulsion polymerisation of styrene using
the completely water soluble catalyst,
[
(
) (
) ]
X
WI2 CO 3 NC5 H4CO2 Na-4 2 , ZrCl4 , sodium
2
w
Ž
.Ž
.Ž
.
x
plexes WI2 CO NCMe h -RC2R , from
lauryl phosphate and sodium hydrogen phos-
phate
w
Ž
. Ž
.
2 x 2
the reaction of WI2 CO NCMe
with ex-
3
X
cess RC2R . This was later extended to the
w
Ž
.Ž
.
molybdenum complexes, MoXY CO NCMe -
X
2
w
x
In 1958, Arhland et al. 28 described the first
Ž
.
x w
x
w x
h -RC2R
23 . In 1996 24 , we descibed
2
Ž
water-soluble phosphine, sodium 3- diphenyl-
the synthesis and crystallographic characterisa-
tion RsR sMe; RsMe, R sPh of the lin-
ear-triphos organometallic phosphines, WI2-
X
X
.
phosphino benzenesulfonate. Transition-metal
complexes containing water-soluble phosphine
ligands are very important in catalytic processes
29,30 . In 1995 31 , we described the synthesis
of the first example of a completely water-solu-
Ž
.
w
X
2
Ž
.Ž
X.Ž
.
x
Ä
Ž
LsPPh CH2CH2-
X
CO L-P, P h -RC2R
X
w
x
w x
.
4
PPh2 2; RsR sMe, Ph; RsMe, R sPh .
w
x
More recently 25 , this was extended to the
X.Ž
.x Ž
2
w
ble seven-coordinate complex, namely WI2-
w
Ž
.Ž
complexes MXY CO L-P, P h -RC2R M
Ž
. Ž
. x
CO NC5H4CO2 Na-4 . This complex was
.
sMo or W; X,YsCl, Br, I; RsMe, Ph ,
which were crystallographically characterised
for MsW, XsBr or I; RsPh. Very recently,
we described the reactions of equimolar quanti-
ties of MI2 CO NCMe
and MeC CH2 PPh2 in
CH2Cl2 at room temperature to give the
3
2
w
Ž
. Ž
. x
prepared by reacting WI2 CO NCMe with
3
2
two equivalents of NC5H4CO2 H-4 in MeOH at
room temperature to yield, WI2 CO NC5-
w
Ž
. Ž
3
w
Ž
. Ž
.
2 x
w Ž .
or MXY CO -
3
.
X
2
Ž
.Ž
2 x
Ž
.
3
NCMe h -RC2R
Table 1
w
X
Ž
.
3
organometallic phosphine ligands, MI2 CO -
Ž .
Preliminary study of the catalytic activity of novel molybdenum II
and tungsten II monodentate phosphines
Us50% conversion to polymer; UUs100% conversion to
X
X
2
Ž
.
x w
x w Ž .Ž
X.Ž
26 and MXY CO L-P,P h -
L-P,P
Ž .
X
.
x
Ä
RC2 R
X s Cl, Br, I, Y s I; LX s
X
X
polymer.
Ž
4
.
3
MeC CH2 PPh2 RsR sMe, Ph; RsMe, R
Where 0.007 mmol of complex was added to 2 cm3 of norborna-
w x
X
sPh 27 , respectively, in good yield. We
have carried out a comparative study of the
catalytic activity of a series of the above com-
plexes towards the metathesis polymerisation of
neat nbd. All experiments were carried out un-
Ž
.
Ž
.
diene. LsPPh CH2CH2 PPh2 2; L sMeC CH2 PPh2
.
3
Complex
1 hrRT 408C 24 hrRT
X
w
w
w
w
w
w
w
w
w
w
Ž
. Ž
X .x
X .x
MoI2 CO L-P, P
X
X
X
X
X
X
X
U
U
UU
X
U
X
X
X
U
X
U
U
X
UU
X
X
X
UU
X
UU
UU
3
X
Ž
. Ž
WI2 CO L-P, P
MoI2 CO L-P, P h -MeC2 Me
MoI2 CO L-P, P h -MeC2 Me
WI2 CO L-P, P h -MeC2 Me
WI2 CO L-P, P h -MeC2 Me
WI2 CO L-P, P h -HC2 Ph
WI2 CO L-P, P h -PhC2 Ph
WBrI CO L-P, P h -PhC2 Ph
3
X
2
Ž
Ž
.Ž
X .Ž
.x
X .Ž
2
.Ž .x
Ž
der exactly the same conditions see experimen-
tal Section 4.6 , and the results summarised in
Table 1. It was found that the most active
2
Ž
Ž
Ž
.Ž
.Ž
.Ž
.Ž
X .Ž
.x
X
X .Ž
.x
.
2
X
X .Ž
.x
.x
.x
.x
2
X
Ž
X .Ž
2
X
catalyst was for MsW, XsCl, YsI, RsR
X
2
Ž
Ž
.Ž
.Ž
X .Ž
X .Ž
X
sPh. Again these results are in agreement with
2
WClI CO L-P, P h -PhC2 Ph
UU UU
w
x
those observed by Hughes 14 , and as de-

(
)
56
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
H4CO2 H-4 , which when reacted with two
C–H stretches at 2922 and 2848 cmy1, suggest-
ing that the monomer, which contains no
aliphatic bonds had been successfully poly-
.
x
2
equivalents of NaOH in EtOH gave the totally
water-soluble complex, WI2 CO NC5H4-
w
Ž
. Ž
3
.
x
Ž
Ž ..
CO2 Na-4 . We have extended the use of these
merised to give polystyrene see Eq. 1 :
2
cheap and easy to prepare water solubilising
substituted pyridine ligands such as NC5H4-
CO2 Na-4 and NC5H4SO3Na-3 to other com-
plexes such as the zero-valent complexes
w
Ž
.
Ž .ny3x Ž
M CO
L M s Cr, Mo, W: L s
n
.
w x
NC5H4CO2 Na-4, NC5H4SO3Na-3, etc. 32
w
Ä
Ž
.Ž
.
.
2
x
and the p-allyl complexes M m-Br CO -
L h -allyl
3
3
Ž .
1
Ž
.
4
x
w
Ž
.
Ž
x w
and MoX CO L2 h -allyl 33 .
2
2
Emulsion polymerisation is an important
1
The room temperature H NMR spectrum in
CDCl3 suggested that the monomer had been
technological process used to prepare acrylic
Ž
.
Ž
polymers, poly vinylchloride , poly vinylace-
Ž
.
converted into polystyrene see Fig. 4 . The
singlet at ds1.57 ppm was assigned to the two
protons Hb, and the singlet downfield at ds
3.48 ppm to the proton Ha attached to the
carbon adjacent to the phenyl ring. The multi-
plet at ds7.06 ppm was assigned to the aro-
matic protons Hc, confirming the synthesis of
polystyrene. We are continuing to develop these
water-soluble pyridine ligands, and their com-
plexes in catalysis.
.
tate , and a number of copolymers. The tech-
nique involves the use of small particles of
diameter 0.05–3 mm and a monomer-insoluble
initiator. The system consists of a monomer,
emulsifying agent, water and a water-soluble
initiator. We have used this technique in the
emulsion polymerisation of styrene using our
w
Ž
. Ž
. x
WI2 CO NC5H 4CO2 Na-4 rZrCl4 co-
3
2
catalyst system.
The emulsion polymerisation of styrene at
708C was initiated by the free radical initiator
potassium persulphate in an emulsion consisting
of the surfactant sodium lauryl sulphate and
sodium hydrogen phosphate in water. The addi-
tion of the reaction solution to an excess of
methanol afforded polystyrene in high yield. In
a similar reaction, the surfactant sodium lauryl
2.5. Polymerisation of phenylacetylene using
[
(
) (
) ] (
WX2 CO 3 NCMe L XsCl, LsNCMe; Xs
[
I, LsNCMe, PPh3 or AsPh3 and WBr2
2
(
)( ) ]
)(
CO NCMe h -HC2 Ph 2
w
x
Over the years, Boroczak et al. 34 , Szyman-
y
2
phosphate, 3.47=10 mol dmy3 and sodium
w
x
ska-Buzar and Ziolkowski 35 and Szyman-
´
Ž
.
y
3
hydrogen phosphate, 7.04=10
mol dmy3
.
w
x
ska-Buzar 36–38 , have studied the catalytic
Ž
were dissolved in water and the solution was
thoroughly degassed, before styrene was added.
To the stirred emulsion was added the aqueous
w
Ž
. Ž
. x
soluble catalyst WI2 CO NC5H4CO2 Na-4 ,
2
3
.
y
3
Ž
3.08=10
mol dmy3 , and the co-catalyst
y2
mol dmy3 were added.
.
Ž
ZrCl4 1.07=10
The solution was allowed to stir at 708C for 5 h,
before being poured into a large excess of
methanol to yield a white polymeric product.
The product was characterised by infrared and
1H NMR spectroscopy. The infrared spectrum
of the polymer as a KBr disc exhibited strong
Fig. 4. The proton assignments of the 1H NMR spectrum of
polystyrene.

(
)
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
57
to elemental analysis, however the complex is
stable when stored and used in the solid state
under a dinitrogen atmosphere.
As a background to this study, we have
w
x
previously described 40 , the trimerisation of
Ž .
Ž
MeC2 Ph using the molybdenum II bis 1-phen-
2
.
w
Ž
.Ž
.Ž
ylpropyne complex, MoI2 CO NCMe h -
MeC2 Ph in the presence of P O Pr , which
gave the crystallographically characterised
i
.
x
Ž
.
2
3
w
x
1,3,4-trimethyl-2,5,6-triphenylbenzene, 40 . We
2
w
x
. Ž
have also shown 41 , that both the diiodide
w
Ž
.Ž
.Ž
. x w
x
Fig. 5. Structure of WI2 CO NCMe h -HC2 Ph
41 .
2
w
Ž
.
2 x
Ž
.
complexes, MI2 CO NCMe
MsMo, W
catalyse the polymerisation of phenylacetylene,
3
Ž .
activity of several tungsten 0 -Lewis acid sys-
tems, and they found the halocarbonyls obtained
in the initial reaction are catalysts for the
metathesis, isomerisation, and polymerisation of
alkenes and alkynes. In 1997, Szymanska-Buzar
and that these polymerisation reactions go via
Ž
.
w
Ž
.
the bis phenylacetylene complex, WI2 CO -
2
Ž
.Ž
.
x w
x
Ž
.
NCMe h -HC2 Ph
41 , see Fig. 5. , which
2
has been crystallographically characterised.
In this paper, we describe preliminary studies
of the catalytic polymerisation of HC2 Ph using
w
x
39 has shown that photochemical oxidation of
w
Ž
.
6x
w
Ž
. Ž
.
2 x Ž . w
W CO
with CCl4 in cylclohexanerCCl4
WX2 CO NCMe
XsCl, I and WI2-
3
Ž
.
w
Ä
Ž
.
Ž
.
4
x
3
Ž
. Ž
.
x
Ž
. w x
10:1 eventually gives W m-Cl Cl CO
,
CO NCMe L LsPPh3, AsPh3 42 and
4 2
.
3 Ž
.Ž
.Ž
.
2 x Ž .
Ž
which
2
w
Ž
w
which reacts with NCMe to give, WCl2 CO -
3 . During the course of our work,
we describe a simpler synthesis of 3 by react-
ing two equivalents of NaCl with WI2 CO -
NCMe , in acetone to give the halide ex-
changed product, 3 see experimental Section
4.8 . We could not isolate this complex in a
WBr2 CO NCMe h -HC2 Ph
was prepared and characterised as described in
4
Ž
.
2 x Ž .
NCMe
Ž .
w
. Ž
.
Section 4.9 see Table 2 . The complexes
2 x
Ž
.
w
Ž
. Ž
.
Ž
.
WX2 CO NCMe
excess phenylacetylene to give orange to red
XsCl or I react with
3
3
Ž
. x
2
Ž . Ž
Ž . Ž .
poly phenylacetylene ppa in high yield. It is
.
w x
interesting that Szymanska-Buzar 39 observed
pure state, as it is very unstable when subjected
that the amount of dimers of phenylacetylene
Table 2
Ž .
Polymerisation of PA catalysed by tungsten II complexes
Ž
.
Ž
.
Ž
.
pa
Ž .
Other products %
Complex
Conversion % Yield %
dpbd
2
1 h
24 h
1,2,3-TPB
1,2,4-TPB
1,3,5-TPB
a
w
w
w
w
w
w
w
w
w
Ž
w
Ž
. Ž
. x
2
WI2 CO NCMe
87
80
33
23
17
27
54
91
60
98
96
95
71
98
97
97
96
95
40
10
36
43
27
5
34
6
25
3
–
5
–
2
–
–
5
–
2
–
10
–
7
–
–
–
5
–
–
–
8
3
6
9
–
5
4
2
14
–
15
13
7
10
–
–
–
1
11
–
–
–
–
2
Ž
.3Ž
. x
b
WI2 CO NCMe
3
a
Ž
. Ž
. x
WCl2 CO NCMe
WCl2 CO NCMe
2
.3Ž
. x
b
Ž
3
2
a
Ž
Ž
Ž
Ž
. Ž
.Ž
.Ž
.Ž
.Ž
.x
.x
WI2 CO NCMe PPh3
WI2 CO NCMe PPh3
WI2 CO NCMe AsPh3
WI2 CO NCMe AsPh3
0.2
.3Ž
b
–
–
5
–
–
5
7
.3Ž
.x
.x
a
0.2
20
10
0.2
19
7
0.2
10
9
.3Ž
b
28
3
3
Ž
.Ž
.
WBr2 CO NCMe
h -HC2 Ph
WBr2 CO NCMe
h -HC2 Ph
2
a
. x
Ž
.Ž2
.
48
94
3
–
–
–
66
–
5
0.1
2
b
Ž
. x
2
a 0.05 mmol of complex 2 cm3 of PA.
b0.05 mmol of complex, 5 mmol of PA in 5 cm3 of toluene.

(
)
58
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
Ž
.
Ž
.
such as diphenylbutadiene dpbd and pa
2
Ä
Ž
.
.
pa 2 s 1H-indene-1-phenylmethylene -from
MS results are higher than when she used the
. 4 x
tungsten dimers such as W m-Cl Cl CO .
4 2
We found significant amounts of these materials
4
w
Ä
Ž
.
Ž
in our reactions.
The ppa observed in these reactions varies
from orange to dark red. They are air stable and
completely soluble in chlorinated solvents such
as CH2Cl2, CHCl3 and aromatic hydrocarbons.
The structure of the ppas obtained were deter-
1
mined by consideration of the IR and H NMR
spectra of the polymers as described by
w
x
Simionescu et al. 43 . The structure was shown
to be the cis-isomer, as there is a strong band at
740 cmy of high intensity, which can be as-
1
cribed to the cis-isomer. The resonances in the
1H NMR spectra are also in accord with cis-iso-
w
x
mer, by comparing with Simionescu et al., 43
data. Molecular weights of the polymers formed
from these reactions are currently being mea-
sured.
The mechanism of the polymerisation reac-
tion almost certainly involves initial coordina-
w
Ž
. Ž
. x
2
tion of the alkynes to WX2 CO NCMe in
3
a two step process as shown in Scheme 3, to
w
Ž
.
eventually give the complexes WX2 CO -
2
Ž
.Ž
.
2 x
Ž
.
NCMe h -HC2 Ph
XsCl or I , which has
w
x
been structurally characterised for XsI 41 ,
see Fig. 5 . The synthesis and characterisation
of the dibromo-complex 4 is given in the
Ž
.
Ž .
experimental Section 4.9, and from the spectro-
y
Ä
Ž
.
14
scopic data IRsn CO s2092 cm
and is
very similar to the crystallographically charac-
2
w
Ž
.Ž
.Ž
terised complex, WI2 CO NCMe h -HC2-
.
x
Ph , is hence very likely to have a similar
2
Ž
.
structure see Fig. 5 . As the alkynes are cis-
and parallel to each other it is likely the two
alkynes couple to give a metallocyclopentadiene
Ž
.
intermediate. The metallocycles Scheme 3
`
could insert an alkyne into a W C bond to give
a seven-membered ring, which could decom-
pose, to give the trimers, 1,2,4- and 1,3,5-tri-
Scheme 3. The proposed mechanism for the polymerisation of
. Ž . x
w
Ž
phenylacetylene using WX2 CO NCMe
.
2
3
w
x
phenylbenzenes. We have previously shown 40
2
w
Ž
.Ž
Ž
.Ž
that the complex MoI2 CO NCMe h -MeC2-
trimerises the alkyne to the crystallographically
characterised arene, 1,3,4-trimethyl-2,5,6-tri-
i
.
Ph
2 x
.
in the presence of P O Pr catalytically
3

(
)
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
59
X
X.Ž
.
x w
x
2
w
w
w
w
w
x
w
Ž
.Ž
phenylbenzene. Addition of a fourth pheny-
lacetylene ligand could rearrange to an alkyli-
24 , MXY CO L-P,
P
h -RC2R
25 ,
X
X
Ž
. Ž
.
x
Ž
.
w
x
MX2 CO L-P, P
MsMo or W 26 ,
3
.Ž
X
X
X.Ž
.
x w x
27 and
2
w
x
Ž
dene as previously described by Yeh et al. 44 .
MXY CO L-P,
P
h -RC2R
Ž
. Ž
.
2 x
w x
31 and
They reacted the zero-valent complex,
WI2 CO NC 5 H 4CO2 Na-4
3
2
w
Ž
.Ž
.
3x
Ž
. Ž
.
x
Ž
. w x
W CO h -PhC2 Ph
with excess PhC2 Ph.
The diphenylbutadiene and triphenylbenzenes
WI2 CO NCMe L LsPPh3 or AsPh3 42
3
were prepared using previously described proce-
dures. All chemicals used were purchased from
commercial sources. All solvents used were
dried before use.
Ž
.
1,2,4 and 1,3,5-tpb detected by GS-MS in a
residue obtained after separating the ppa with
MeOH, also gives evidence for the formation of
metallocyclopentadiene and metallocyclohepta-
Ž
.
Elemental analyses C, H and N were deter-
mined on a Carlo Erba Analyser MOD 1108
using helium as a gas carrier . IR spectra were
Ž
trienes as intermediates Table 2 and Scheme
.
3 .
Ž
.
carried out on a Perkin-Elmer 1600 FTIR spec-
1
trophotometer. H and 13C NMR spectra were
3. Conclusions
obtained out on a Bruker AC 250 NMR spec-
trometer, and referenced to SiMe4.
w
The seven-coordinate complexes MXY-
2 x
The analysis of the products from the cat-
alytic reactions were carried out on a Finnigan
4500 Automated GC-MS.
Ž
. Ž
.
Ž
.
MsMo, W; X, Yshalide
CO NCMe
3
and their wide range of derivatives undergo a
variety of catalytic reactions with or without a
co-catalyst including, metathesis polymerisation
of norbornadiene, emulsion poymerisation of
styrene and trimerisation and polymerisation of
alkynes. Several of the catalytic intermediates,
4.1. Attempted ring-opening metathesis of nor-
[
(
) (
) ]
bornadiene using MoI2 CO 3 NCMe 2 in
toluene
Ž .
including 1 have been identified and fully
w
Ž
. Ž
.2 x
To a suspension of MoI2 CO NCMe
3
characterised.
3
Ž
.
Ž
Ž
.
0.15 g, 0.2908 mmol in toluene 20 cm was
We are continuing to explore the catalytic
activity of these versatile complexes and their
derivatives, including attempts to develop multi-
3
added norbornadiene 6.28 cm , 5.36 g, 58.17
mmol . After stirring for 24 h, the solution was
poured into methanol 200 cm . A polymeric
.
3
Ž
.
Y
Y
w
x Ž
functional catalysts such as RhClL3 L s
product was not isolated.
X
X
w
Ž
.Ž
X.Ž
.
x
.
w
2
MXY CO L-P, P h -RC2R
and Co2-
w
Ž
. Ž
.2 x Ž
Similar reactions of WI2 CO NCR R
sMe, Bu or Ph with norbornadiene did not
Y
3
Ž
.
x
CO L , which might be mixed hydrogenation
Rh rmetathesis Mo or W or hydroformyla-
tion Co rmetathesis Mo or W catalysts, re-
t
7
.
Ž
.
Ž
.
produce a polymer.
Ž
.
Ž
.
spectively.
4.2. Ring-opening metathesis of norbornadiene
[
(
) (
) ]
using MoI2 CO 3 NCMe 2 in the presence of
ZrCl4
4. Experimental
Ž
To a stirred solution of norbornadiene 6.0
cm , 5.12 g, 55.61 mmol in toluene 20 cm
The synthesis, purification and other opera-
tions used in the catalytic work were carried out
in an inert atmosphere using standard
vacuumrSchlenk line techniques. The starting
3
3
.
Ž
.
Ž
.
was added ZrCl4 0.19 g, 0.8342 mmol and
w
Ž
. Ž
.
2 x
Ž
.
MoI2 CO NCMe
After stirring for 10 min, the solution was poured
into methanol 200 cm to afford poly norbor-
. Ž .
nadiene . Yields1.89 g, 37% .
0.14 g, 0.2781 mmol .
3
w
Ž
. Ž
.
2 x
Ž
.
materials, MX2 CO NCMe
MsMo, W
3
3
w x w
Ž
. Ž
.
x
Ž
Ž
.
Ž
1 , MoBr2 CO NCMe L LsPPh3, AsPh3,
3
X
2
.
w x
w
Ž
.Ž
X.Ž
.
x
SbPh3
5 , WI2 CO L-P,
P
h -RC2R

(
)
60
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
4.3. Ring-opening metathesis of norbornadiene
) ( ) ]
Elemental analysis : C7H8O2I2W requires
[
(
using MoBr2 CO 3 NCMe 2
Cs14.9, Hs1.5%; Found Cs14.4, Hs
1.4%. IR CHCl3 n CO s2044 cm
;
1H
y
1
Ž
.
Ž
.
w
Ž
. Ž
.2 x Ž
To MoBr2 CO NCMe 0.12 g, 0.2845
3
Ž
.
Ž
NMR CDCl3,q258C : ds5.80 m, 1H, iso-
H , 3.68 q, Js7.86 Hz, 4H, iso-H , 1.28 t,
3
.
Ž
.
.
Ž
.
Ž
mmol dissolved in thf 20 cm with constant
3
Ž
.
stirring, was added norbornadiene 6.14 cm ,
5.24 g, 56.90 mmol . After stirring for 15 min,
Js8.57, 3H, C H3 ppm.
.
X
Ž
[
(
)(
the solution was poured into methanol 200
4.6. Catalytic studies using MXY CO L-P,
X)(
X)]
cm3 to afford poly norbornadiene . Yields
2
.
Ž
. Ž
P h -RC2 R and related complexes
.
1.41 g, 27% .
3
w
.Ž
Ž
. Ž
.
2 x
Ž
.
Similar reactions of WBr2 CO NCMe
and WBr2 CO NCMe EPh3 EsP, As or
Ph with norbornadiene in thf at room tempera-
Norbornadiene 2 cm , 1.86 g, 18.21 mmol
3
X
X.Ž
.x
2
w
Ž
. Ž
.
x
Ž
w
Ž
.Ž
was added to WBrI CO L-P, P h -PhC2 Ph
3
.
Ž
.
0.008 g, 0.007 mmol and the solution was
Ž
.
ture, gave poly norbornadiene .
stirred at room temperature for 1 h. The solution
was poured into methanol to afford poly-
( )
4.4. Preparation and characterisation of 1
Ž
. Ž
.
norbornadiene . Yields1.58 g, 85% .
Similar catalytic studies of the complexes,
X
X
2
w
Ž
. Ž
.
2 x
Ž
w
Ž
. Ž
.
x w
Ž
.Ž
X.Ž
To WI2 CO NCMe
0.51 g, 0.8449
MI2 CO L-P, P , MXY CO L-P, P h -
3
3
X
X.Ž
.
x
3
2
.
Ž
.
.
x
w
Ž
.Ž
mmol suspended in hexane 60 cm with con-
RC2R’ and MXY CO L’-P, P h -RC2R
stant stirring under a stream of dry nitrogen was
were carried out in an exactly analogous manner
and the results of these preliminary studies are
given in Table 1.
3
Ž
.
added nbd 0.21 cm , 1.95 mmol . After reflux-
ing for 6 h, the solvent was removed in vacuo,
and the resulting dark green product was resol-
3
Ž
.
vated in CH2Cl2 70 cm and filtered. The
solvent was removed in vacuo and the green
product was recrystallised from CH2Cl2rEt2O
at y178C to give the analytically pure complex,
4.7. Emulsion polymerisation of styrene using
[
(
) (
) ]
WI2 CO 3 NC5 H4CO2 Na-4 2 in the presence
of ZrCl4
Ž . Ž
.
w
Ž
. Ž
3
1 . Yields0.08 g, 17% .
Elemental analysis : C9H8O2 I2W requires
To a stirred solution of WI2 CO NC5-
.
2 x Ž .
0.05 g, 0.0616 mmol dissolved
H4CO2 Na-4
3
Ž
.
Cs18.4, Hs1.4%; Found Cs18.3, Hs
in H2O 20 cm was added sodium lauryl
sulphate 0.2 g, 0.6935 mmol and sodium hy-
Ž
.
Ž
.
Ž .
Ž .
Ž .
2.2%. IR CHCl3 n CO s2057 w , 1989 s
1
1
cmy . H NMR CDCl3,q258C : ds4.52 m,
Ž
.
Ž
Ž .
drogen phosphate 0.02 g, 0.1409 mmol . The
.
Ž
.
Ž
.
Ž .
4H , 3.94 m, 2H , 0.56 t, 2H ppm.
co-catalyst ZrCl4 0.05 g, 0.2146 mmol was
3
Ž
added to the styrene 10 g, 10.21 cm , 89.11
mmol , before being added to the aqueous solu-
( )
4.5. Preparation and characterisation of 2
.
tion. The solution was allowed to stir at 708C
3
w
Ž
. Ž
.
x
Ž
Ž
.
To WI2 CO NCMe
0.5 g, 0.8283
for 5 h, and added to methanol 200 cm to
3
2 Ž
.
Ž
.
3
.
mmol dissolved in CHCl3 60 cm with con-
produce polystyrene. Yields6.5 g, 65 % .
stant stirring under a stream of dry nitrogen was
3
Ž
. Ž
.
( )
added isoprene iso 0.17 cm , 2.4849 mmol .
After refluxing for 24 h, the solution was fil-
tered and the solvent removed in vacuo. The
resultant brown product was washed with hex-
ane 15 cm CH2Cl2 70 cm to afford the
analytically pure complex 2 . Yields0.27 g,
4.8. Preparation and characterisation of 3
w
Ž
. Ž
.2 x
To a stirred solution of WI2 CO NCMe
3
3
Ž
.
Ž
.
2 g, 3.3 mmol in acetone 25 cm was added
3
3
Ž
.
Ž
.
Ž
.
two equivalents of NaCl 0.38 g, 6.6 mmol .
After 24 h, the solution was filtered and the
solvent removed in vacuo. The resultant dark
Ž . Ž
.
57% .

(
)
M. Al-Jahdali et al.rJournal of Molecular Catalysis A: Chemical 159 2000 51–62
61
green oil was recrystallised from CH2Cl2 to
Acknowledgements
Ž . Ž
.
afford 3 . Yields0.305 g , 22% .
Ž
.
Ž
.
Ž .
Ž .
IR CHCl3 n N'C s2305 w , 2359 w
Ž
.
We thank the EPSRC MMM, DJM ,
1
cmy ; n CO s2080 s , 2009 s and 1949 s
Ž
.
Ž .
Ž .
.
Ž .
Ž
.
.
ZENECA Specialties DJM and the Saudi Ara-
bian Government M Al. J for supporting this
1
cmy . H NMR CDCl3,q258C : ds2.40, s,
1
Ž
Ž
Ž
13
.
Ž
Ž
.
3H, NC Me ppm; C NMR CDCl3,q258C :
work.
Ž
.
.
ds4.20 s, NC Me , 124.13 s, N'C , 200.4
s, C'O ppm.
Ž
.
References
( )
4.9. Preparation and characterisation of 4
w x
1
P.K. Baker, S.G. Fraser, E.M. Keys, J. Organomet. Chem.
Ž
.
w
Ž
. Ž
.
2 x
309 1986 319.
To a stirred solution of WBr2 CO NCMe
3
w x
2
3
P.K. Baker, M.M. Meehan, M.G.B. Drew, Transition Met.
Ž
.
Ž
.
1 g, 1.86 mmol in CH2Cl2 30 cm was
Ž
.
Chem. 24 1999 333.
Ž
added phenylacetylene 0.38 g, 0.40 ml, 3.72
mmol . After 24 h, the solution was filtered and
the solvent removed in vacuo. The resultant
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w x
3
M.G.B. Drew, P.K. Baker, E.M. Armstrong, S.G. Fraser,
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Ž
.
1995 617.
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4
Ž
.
D.P. Tate, W.R. Knipple, J.M. Augl, Inorg. Chem. 1 1962
433.
Ž . Ž
CH2Cl2rEt2O to afford 4 Yields0.95 g,
w x
5
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.
85% .
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Ž
.
Dalton Trans. 1994 3493.
w x
6
P.K. Baker, T. Birkbeck, S. Brase, A. Bury, H.M. Naylor,
¨
Ž
.
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w x
7
Ž
.
Ž
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Ž
.
y
1
dron 12 1993 357.
.
Ž .
Ž .
Ž
Ž
.
C s2343 w , 2321 w cm ; n CO s2092
w x
8
Ž
.
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1
y
1
Ž .
Ž
Ž
.
s cm . H NMR CDCl3, q258C : ds2.2
139.
.
Ž
. .
w x Ž .
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s, 3H, NCMe , 7.7–7.4 m, 10 H, Ph , , 11.1
w
w
w
w
x
Ž
.
10 P.K. Baker, Adv. Organomet. Chem. 40 1996 45.
.
s, 2H, C2 H ppm.
x
Ž
.
11 P.K. Baker, Chem. Soc. Rev. 27 1998 125.
x
Ž
.
12 L. Bencze, A. Kraut-Vass, J. Mol. Catal. 28 1985 369.
x
13 L. Bencze, A. Kraut-Vass, L. Prokai, J. Chem. Soc., Chem.
´
4.10. Polymerisation of HC2 Ph studies
Ž
.
Commun. 1985 911.
w
w
x
Ž
.
14 W.B. Hughes, Organomet. Chem. Synth. 1 1972 341.
x
15 J.L. Davidson, G. Vasapollo, J. Chem. Soc., Dalton Trans.
Generally, the toluene solution of pa and the
Ž
.
1985 2231.
w
w
w
x
Ž
.
16 L. Carlton, J.L. Davidson, G. Vasapollo, G. Douglas, K.W.
internal standard xylene was added to the
catalyst, and the formation of pa was monitored
by chromatography. The reactions were contin-
ued for 24 h and methanol was added to precipi-
tate the polymer, which was collected, recrys-
tallised from CH2Cl2rMeOH, dried in vacuo
Ž
.
Muir, J. Chem. Soc., Dalton Trans. 1993 3341.
x
17 T. Daniel, H. Nagao, K. Tanaka, A. Nakamura, Chem. Ber.
Ž
.
128 1995 1007.
x
18 T. Daniel, H. Nagao, H. Nakajima, K. Tanaka, A. Nakamura,
Ž
.
J. Organomet. Chem. 509 1996 225.
w
w
w
x
Ž
.
19 T. Szymanska-Buzar, T. Gowiak, Polyhedron 16 1997 1599.
x
Ž
.
20 F.A. Cotton, J.H. Meadows, Inorg. Chem. 23 1984 4688.
1
and analysed by IR and H NMR spectroscopy.
x
21 P.K. Baker, M.G.B. Drew, M.M. Meehan, unpublished re-
sults.
The filtrate, which was obtained after precipi-
tation of the various polymers, was evaporated
to dryness, and the residue was dissolved in
CH2Cl2 and then analysed by GC-MS. Analysis
of the products showed that there were mainly
diphenylbutadiene and triphenylbenzenes. The
results of this work are given in Table 2.
w
w
w
w
x
22 E.M. Armstrong, P.K. Baker, M.G.B. Drew, Organometallics
Ž
.
7 1988 319.
x
23 N.G. Aimeloglou, P.K. Baker, M.M. Meehan, M.G.B. Drew,
Ž
.
Polyhedron 17 1998 3455.
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24 P.K. Baker, S.J. Coles, D.E. Hibbs, M.M. Meehan, M.B.
Ž
.
Hursthouse, J. Chem. Soc., Dalton Trans. 1996 3995.
x
25 P.K. Baker, M.G.B. Drew, M.M. Meehan, J. Szewczyk, J.
Ž
.
Organomet. Chem. 580 1999 265.

(
)
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w
w
x
w
x
35 T. Szymanska-Buzar, J.J. Ziolkowski, J. Mol. Catal. 43
´ ´
26 M. Al Jahdali, P.K. Baker, M.M. Meehan, unpublished re-
Ž
.
sults.
1987 161.
x
w
w
w
w
w
x Ž .
36 T. Szymanska-Buzar, J. Mol. Catal. 48 1988 43.
´
27 P.K. Baker, D.S. Evans, M.M. Meehan, A. Miller, unpub-
x Ž .
37 T. Szymanska-Buzar, J. Mol. Catal. 68 1991 177.
´
lished results.
x
x Ž .
38 T. Szymanska-Buzar, J. Mol. Catal. 93 1994 137.
´
28 S. Arhland, J. Chatt, N.R. Davies, A.A. Williams, J. Chem.
Ž
.
x Ž .
39 T. Szymanska-Buzar, J. Mol. Catal 123 1997 113.
´
Soc. 1958 264.
w
w
x
x
Ž
.
x
40 P.K. Baker, M.G.B. Drew, D.S. Evans, A.W. Johans, M.M.
29 E.G. Kuntz, CHEMTECH 17 1987 570.
30 A.F. Borowski, D.J. Cole-Hamilton, G. Wilkinson, New J.
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´
Ž
.
w
w
w
w
x
Chem. 2 1978 137.
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w
x
31 P.K. Baker, A.E. Jenkins, A.J. Lavery, D.J. Muldoon, A.
Chem. Commun., submitted.
Ž
Ž
.
.
x
Ž
.
Shawcross, J. Chem. Soc., Dalton Trans. 1995 1525.
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w
w
x
x
32 P.K. Baker, A.E. Jenkins, Polyhedron 16 1997 2279.
33 P.K. Baker, A.E. Jenkins, J. Organomet. Chem. 545–546
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x
43 C.J. Simionescu, V. Percec, S. Dumitrescu, J. Polym. Sci.,
Ž
.
Ž .
Polym. Chem. 15 1977 2497.
1997 125.
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x
x
34 D. Borowczak, T. Szymanska-Buzar, J.J. Ziolkowski, J. Mol.
44 W.-Y. Yeh, S.-M. Pengband, G.-H. Lee, J. Chem. Soc.,
´
Ž
.
Ž .
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