Preparation, characterization, and X-ray structure of the 1:1 complex of o-acetylstyrene and carbonylbis(triphenylphosphine)ruthenium. A new catalyst for the copolymerization of acetophenone and 1,3-divinyltetramethyldisiloxane

Article abstract of DOI:10.1021/om9708541

Treatment of dihydridocarbonyltris(triphenylphosphine)ruthenium with a stoichiometric amount of styrene, followed by addition of o-acetylstyrene leads to a 1:1 complex of o-acetylstyrene and carbonylbis(triphenylphosphine)ruthenium. This species has been fully characterized and its structure determined by X-ray crystallography. This 1:1 complex is able to catalyze the copolymerization of acetophenone and 1,3-divinyltetramethyldisiloxane.

Full text of DOI:10.1021/om9708541

584
Organometallics 1998, 17, 584-588
P r ep a r a tion , Ch a r a cter iza tion , a n d X-r a y Str u ctu r e of
th e 1:1 Com p lex of o-Acetylstyr en e a n d
Ca r bon ylbis(tr ip h en ylp h osp h in e)r u th en iu m . A New
Ca ta lyst for th e Cop olym er iza tion of Acetop h en on e a n d
1,3-Divin yltetr a m eth yld isiloxa n e†
Ping Lu, J yri Paulasaari, Kevin J in, Robert Bau, and William P. Weber*
K. B. and D. P. Loker Hydrocarbon Research Institute, Department of Chemistry,
University of Southern California, Los Angeles, California 90089-1661
Received October 2, 1997
Treatment of dihydridocarbonyltris(triphenylphosphine)ruthenium with a stoichiometric
amount of styrene, followed by addition of o-acetylstyrene leads to a 1:1 complex of o-ace-
tylstyrene and carbonylbis(triphenylphosphine)ruthenium. This species has been fully
characterized and its structure determined by X-ray crystallography. This 1:1 complex is
able to catalyze the copolymerization of acetophenone and 1,3-divinyltetramethyldisiloxane.
In tr od u ction
divinyltetramethyldisiloxane gave low molecular weight
polymers or oligomeric materials.3 The properties of
oligomers depend greatly on their molecular weight,
whereas the properties of a polymer do not change a
great deal once a minimum molecular weight is achieved.
For this reason, synthetic polymer chemists strive to
prepare new materials of sufficient molecular weight
that the properties measured do not change appreciably
with small variation in polymer molecular weights.
Exact stoichiometric balance is essential to obtain high
molecular weight materials in step-growth polymeriza-
tion. We have previously spectroscopically detected the
presence of ethyl end groups bonded to silicon in the
dihydridocarbonyltris(triphenylphosphine)ruthenium-
catalyzed copolymerization of 1,3-divinyltetramethyl-
disiloxane and xanthone.7 To explain this observation,
we have suggested that dihydridocarbonyltris(triphen-
ylphosphine)ruthenium is capable not only of activating
the C-H bonds which are ortho to an aromatic carbonyl
group, but also of transferring its hydrogen atoms to
one of the C-C double bonds of the 1,3-divinyltetra-
methyldisiloxane to yield 1-ethyl-3-vinyltetramethyl-
disiloxane. This process disrupts the stoichiometric
balance by converting a difunctional monomer into a
monofunctional terminating group which limits the
polymer molecular weight.
In late 1993, Murai et al. reported that dihydridocar-
bonyltris(triphenylphosphine)ruthenium catalyzes the
ortho-alkylation reaction of acetophenone with vinyl
silanes.1,2 Similarly, we have found that acetophenones
and other aromatic ketones undergo ruthenium-cata-
lyzed step-growth copolymerization with R,ω-divinylsi-
lanes such as 1,3-divinyltetramethyldisiloxane.3-6 These
reactions involve ruthenium-catalyzed anti-Markovni-
kov addition of the ortho C-H bonds of acetophenones
across the C-C double bonds of the vinyl silane or 1,3-
divinyltetramethyldisiloxane. We have worked to define
the scope and determine the mechanism of this new
transition-metal-catalyzed copolymerization reaction
which involves catalytic C-H activation. While the
reaction is successful with a variety of aromatic ketones,
such as substituted acetophenones, anthrone, fluo-
renone, and xanthone,7 the range of vinyl compounds
which are successful substrates has proved to be quite
limited. The C-C double bonds of vinyl silanes, vinyl
siloxanes, and the vinyl group of styrene react success-
fully.2,8
Initial ruthenium-catalyzed copolymerization reac-
tions between acetophenone and R,ω-dienes such as 1,3-
† This paper is dedicated to a great scientist and dear friend Prof.
George A. Olah on the occasion of his 70th birthday.
(1) Murai, S.; Kakiuchi F.; Sekine, S.; Tanaka, Y.; Sonoda, M.;
Chatani N. Nature (London) 1993, 366, 529.
(2) Kakiuchi, F.; Sekine, S.; Tanaka, Y.; Kamatani, A.; Sonoda, M.;
Chatani, N.; Murai, S. Bull. Chem. Soc. J pn. 1995, 68, 62.
(3) Guo, H.; Weber, W. P. Polym. Bull. 1994, 32, 525.
(4) Tapsak, M. A.; H. Guo, H.; Weber, W. P. Polym. Bull. 1995, 34,
49.
(5) Guo, H.; Tapsak, M. A.; Wang, G.; Weber, W. P. Synthesis of
High Molecular Weight Polymers by Ruthenium Catalyzed Step-Growth
Copolymerization of Acetophenones with R,ω-Dienes in Step Growth
Polymers for High Performance Materials; Hedrick, J . L., Labadie, J .
W., Eds., ACS Symposium Series 624; American Chemical Society:
Washington, D.C., 1996.
In fact, we have speculated that loss of hydrogen from
the ruthenium center, which creates a site of unsatura-
tion, may be essential in activating the catalyst for the
copolymerization reaction. On the basis of this analysis,
we have treated dihydridocarbonyltris(triphenylphos-
phine)ruthenium with a stoichiometric amount of sty-
rene for a few minutes at 120 °C. Under these condi-
tions, the styrene is completely converted to ethylben-
zene (Figure 1). Similarly, stoichiometric hydrogenation
of trimethoxyvinylsilane by dihydridocarbonyltris(triph-
enylphosphine)ruthenium has been reported by Murai.2
Subsequent addition of an equimolar mixture of ac-
etophenone and 1,3-divinyltetramethyldisiloxane to the
(6) Guo, H.; Wang, G.; Tapsak, M. A.; Weber, W. P. Macromolecules
1995, 28, 5686.
(7) Guo, H.; Tapsak, M. A.; Weber, W. P. Polym. Bull. 1995, 34, 49.
(8) Lu, P.; Paulasaari, J .; Weber, W. P. Macromolecules 1966, 29,
8583.
S0276-7333(97)00854-6 CCC: $15.00 © 1998 American Chemical Society
Publication on Web 01/24/1998

A 1:1 Ru-o-Acetylstyrene Complex
Organometallics, Vol. 17, No. 4, 1998 585
F igu r e 1.
activated catalyst results in a significantly higher
molecular weight copolymer.6
F igu r e 2.
Resu lts a n d Discu ssion
We have attempted to characterize the activated
ruthenium species obtained by treatment of dihydri-
docarbonyltris(triphenylphosphine)ruthenium with a
stoichiometric amount of styrene. For reference, we
1
F igu r e 3.
have included the most salient features of the H and
31P NMR spectra of dihydridocarbonyltris(triphenylphos-
phine)ruthenium, which have not been previously re-
have been unsuccessful. Remarkably, the solution
maintains its catalytic activity at room temperature for
some time. Thus, addition of an equimolar mixture of
acetophenone and 1,3-divinyltetramethyldisiloxane to
a solution of the active catalyst which has been stored
for 24 h at room temperature results in formation of
copoly(2-acetyl-1,3-diphenylene/3,3,5,5-tetramethyl-4-
oxa-3,5-disila-1,7-heptanylene)4,6 (Figure 2).
To obtain very high molecular weight polymers, we
have treated o-acetylstyrene11 with a catalytic amount
of activated catalyst. This monomer was chosen be-
cause it has exactly one activated ortho C-H and one
terminal vinyl group. Unfortunately, instead of the
expected high molecular weight polymer, a small amount
of a 1:1 complex between o-acetylstyrene and carbon-
ylbis(triphenylphosphine)ruthenium was obtained. When
a similar reaction was carried out between o-acetylsty-
rene and a stoichiometric amount of activated catalyst,
an 80% yield of recrystallized 1:1 complex was obtained
in addition to 1 equiv of free triphenylphosphine (Figure
3).
1
ported. The H NMR spectrum is characterized by two
resonances at δ -8.18 (dtd, 1H, J P-H ) 74, 27.7 Hz,
J H-H ) 6.5 Hz) and -6.35 (tdd, 1H, J P-H ) 30.2 14.8
Hz, J H-H ) 6.5 Hz) which are assigned to the two
nonequivalent Ru-H bonds. These cis and trans J P-H
coupling constants are similar to those reported for
dihydidocarbonyltris(triphenylphosphine)osmium.9 Two
nonequivalent phosphorus signals are observed in the
31P NMR at δ 45.91 (t, 1P, J P-P ) 18.3 Hz) and 58.08
(d, 2P, J P-P ) 18.3 Hz).
As expected, no resonances due to Ru-H bonds are
observed in the 1H NMR of the styrene-activated
ruthenium complex. The 31P NMR of this activated
ruthenium species is characterized by a number of
resonances. Those at δ -4.84 and 25.47 are assigned
to free triphenylphosphine and a small amount of tri-
phenylphosphine oxide, respectively.10 On the basis of
the integration of the 31P NMR, one of the triphen-
ylphosphine ligands has been lost from the ruthenium
center.
The 1:1 complex of o-acetylstyrene with carbonylbis-
(triphenylphosphine)ruthenium is structurally most
interesting (Figure 4). The X-ray structure and crystal-
lographic data clearly show a strong bond between the
carbonyl oxygen and the ruthenium center in the solid
state. This interaction persists in solution, as shown
by the phosphorus-carbon coupling which is observed
in the 13C NMR resonances assigned to the acetyl
carbonyl group. The C-C double bond of o-acetylsty-
rene is strongly π-coordinated to the ruthenium center
in the solid state. Specifically the C-C bond length is
1.43 Å, which is approximately intermediate between
a C-C single bond and a C-C double bond length. Both
the Ru-C bond lengths and the C-C bond length are
comparable to those reported for the 16-electron system
bis(styrene)bis(triphenylphosphine)ruthenium(0) by
Wilkinson12 and for other similar ruthenium π com-
plexes13 such as the o-styrenyldiphenylphosphine com-
plexof ruthenium tricarbonyl.14 This ruthenium π-co-
Murai has previously examined a number of ruthe-
nium complexes for catalytic activity in this type of
reaction. While dihydridocarbonyltris(triphenylphos-
phine)ruthenium is most active, he has also observed
that triscarbonylbis(triphenylphosphine)ruthenium is
modestly effective, whereas ruthenium carbonyl [Ru3-
(CO)12] is not.2 On the basis of this observation, Murai
has suggested that a zerovalent ruthenium having at
least two triphenylphosphine ligands is essential for
catalytic activity. Neither hydrogen nor carbon mon-
oxide are essential ligands. While it is tempting to
propose that the active ruthenium species is the 14-
electron system carbonylbis(triphenylphosphine)ruthe-
nium, the 31P NMR spectrum of the activated ruthenium
solution shows several phosphorus signals which are not
consistent with those expected for carbonylbis(triphen-
ylphosphine)ruthenium. We suggest that dimeric and/
or trimeric carbonylbis(triphenylphosphine)ruthenium
species which are in equilibrium with a small amount
of carbonylbis(triphenylphosphine)ruthenium may be
present in solution. Attempts to crystallize such species
from the solution of the activated ruthenium catalyst
(11) Weir, N. A.; Whiting, K., Arct, J .; McCulloch, G. Eur. Polym. J
1988, 24, 37.
(12) de C. T. Carrondo, M. A. A. F.; Chaudred, B. N.; Cole-Hamilton,
D. J .; Skapski, A. C.; Wilkinson, G. J . Chem. Soc., Chem. Commun
1978, 463.
(13) Schmid, H.; Ziegler, M. L. Chem. Ber 1976, 109, 132.
(14) Bennett, M. A.; J ohnson, R. N.; Tomkins, I. B. J . Am. Chem.
Soc 1974, 96, 61.
(9) Ahmad, N.; Robinson, S. D.; Uttley M. F. J . Chem. Soc., Dalton
Trans. 1972, 843.
(10) Gorenstein, D. G. Phosphorus 31 NMR, Principles and Applica-
tions; Academic Press: New York, 1984; p 553.

586 Organometallics, Vol. 17, No. 4, 1998
Lu et al.
used as the eluting solvent at a flow rate of 0.8 mL/min. The
retention times were calibrated against those of known mono-
disperse polystyrene standards: Mw 929 000, 212 400, 47 500,
13 700, and 794 whose Mw/Mn are less than 1.09.
X-r a y Str u ctu r e An a lysis. A crystal of dimensions 0.65
× 0.48 × 0.23 mm3 was mounted on a glass fiber with oil and
placed in a Siemens P4/RA diffractometer for data collection
at -120 °C. The angular settings of 26 well-centered reflec-
tions indicated a monoclinic unit cell whose dimensions are
given in Table 1. Four monitor reflections indicated no
significant decrease in intensity during data collection, which
was carried out with Cu KR radiation up to a 2θ maximum of
90°. The position of the Ru atom and the six atoms attached
to it were obtained from a Patterson map with the crystal-
lographic package SHELX-86.16 The rest of the non-hydrogen
atoms were subsequently located from a series of structure
factor/difference-Fourier calculations.17 The vinyl group was
found to coordinate to the Ru atom in a π fashion, forming a
three-membered ring. The important bond lengths and angles
in the 1:1 complex are given in Table 2. The X-ray analysis
was completed with several cycles of full-matrix least-squares
refinements, with anisotropic thermal parameters assigned to
all atoms. The final agreement factor was R(F) ) 6.4% for
2761 nonzero reflections with F > 4σ(F).
F igu r e 4. X-ray structure of the 1:1 complex of o-acetyl-
styrene and carbonylbis(triphenylphosphine)ruthenium.
Elemental analysis was performed by Oneida Research
Services, Whitesboro, NY. All reactions were run in flame-
dried glassware under an inert atmosphere of argon.
ordinated structure persists in solution, as shown by the
phosphorus-carbon coupling in the 13C NMR reso-
nances which are assigned to the π-coordinated C-C
double bond.
R ea gen t s. Dihydridocarbonyltris(triphenylphosphine)-
ruthenium was prepared from ruthenium trichloride trihy-
drate.18
o-Acetylstyrene was prepared following a literature proce-
dure11 from N-acetyl 2-phenylethylamine. The final step in
this synthesis involves the sequential base-induced fragmenta-
tion of 3,4-dihydro-1,2-dimethylisoquinolinium bisulfate to
yield the N-methyl imine of o-acetylstyrene, which undergoes
hydrolysis to yield o-acetylstyrene. In this reaction, o-propio-
nylstyrene is formed as a byproduct. The yield of o-acetylsty-
rene was 54%, while o-propionylstyrene was obtained in 6%
yield. These compounds were separated by column chroma-
tography on a silica gel column. o-Acetylstyrene was eluted
first with a mixed solvent system of ethyl acetate (2.5%) and
pentane (97.5%). Subsequently, o-propionylstyrene was eluted
with a mixture of ethyl acetate (8%) and pentane (92%).
o-Acetylstyrene has the following spectral properties: 1H
NMR δ 2.58 (s, 3H), 5.35 (dd, 1H, J ) 10 and 1.5 Hz), 5.65
(dd, 1H, J ) 17.5 and 1.5 Hz), 7.22 (dd, 1H, J ) 17.5 and 10
Hz), 7.33 (dt, 1H, J ) 7.5 and 1.25 Hz), 7.46 (dt, 1H, J ) 7.5
and 1.25 Hz), 7.57 (dd, 1H, J ) 7.5 and 1.25 Hz), 7.64 (dd,
1H, J ) 7.5 and 1.25 Hz); 13C NMR δ 29.61, 116.42, 127.30,
127.35, 128.56, 131.44, 135.75, 137.20, 137.48, 201.74.
A similar 1:1 complex between o-proprionylstyrene15
and carbonylbis(triphenyl phosphine)ruthenium has
been prepared and fully characterized. Finally, it
should be noted that the 1:1 complex of o-acetylstyrene
and carbonylbis(triphenylphosphine)ruthenium and the
analogous 1:1 complex of o-proprionylstyrene are able
to catalyze the copolymerization of acetophenone and
1,3-divinyltetramethyldisiloxane.6 This may involve
dissociation of these 1:1 complexes to yield catalytically
active carbonylbis(triphenylphosphine)ruthenium or re-
lated oligomeric polynuclear ruthenium complexes (Fig-
ure 5).
Exp er im en ta l Section
1H, 13C, and 31P NMR spectra were obtained on a Bruker
AC-250, AM-360, or AMX 500 spectrometer operating in the
FT mode. Ten percent w/v solutions in chloroform-d or
benzene-d6 were used to obtain the NMR spectra. 13C NMR
spectra were run with broad-band proton decoupling. Residual
benzene or chloroform were used as internal standards for the
1H and 13C NMR spectra. 31P NMR spectra were run with
broad-band proton decoupling and were externally referenced
to 85% phosphoric acid. IR spectra of thin films on sodium
chloride plates were recorded on a Perkin-Elmer 2000 FT-IR
spectrometer. UV spectra of cyclohexane solutions were
acquired on a Shimadzu UV-260 UV-vis spectrometer.
GPC analysis of the molecular weight distribution of the
o-Proprionylstyrene15 has the following spectral proper-
ties: 1H NMR δ 1.07 (t, 3H, J ) 7.5 Hz), 2.78 (q, 2H, J ) 7.5
Hz), 5.21 (dd, 1H, J ) 11 and 1.5 Hz), 5.51 (dd, 1H, J ) 17.5
and 1.5 Hz), 6.98 (dd, 1H, J ) 17.5 and 11 Hz), 7.20 (dt, 1H,
J ) 7.5 and 1.5 Hz), 7.31 (dt, 1H, J ) 7.5 and 1.5 Hz), 7.44
(td, 2H, J ) 7.5 and 1.5 Hz); 13C NMR δ 8.17, 35.08, 116.35,
127.12, 127.63, 130.00, 130.92, 135.48, 136.97, 137.81, 205.45.
P r ep a r a tion of th e 1:1 Com p lex of o-Acetylstyr en e a n d
Ca r bon ylbis(tr ip h en ylp h osp h in e)r u th en iu m . In a 25 mL
three-necked flask equipped with a reflux condenser and two
rubber septa was placed dihydridocarbonyltris(triphenyl-
phosphine)ruthenium (459 mg, 0.5 mmol), which had been
purified by column chromatography on an alumina column
polymeric materials was performed on
a Waters system
composed of a U6K injector, a 510 HPLC solvent delivery
system, a R401 refractive index detector, and a model 820
Maxima control system. Two linear Waters Styragel 7.8 mm
× 30 cm columns HR1 and HR4 in series packed with <5 µm
particles of monodisperse cross-linked styrene divinylbenzene
copolymer were used for the analysis. HPLC-grade THF was
(16) Sheldrick, G. M. SHELX-86; University of Go¨ttingen: Go¨ttin-
gen, Germany, 1986.
(17) Sheldrick, G. M. SHELX-93; University of Go¨ttingen: Go¨ttin-
gen, Germany, 1993.
(18) Levison, J . J .; Robinson, S. D. J . Chem. Soc. A 1970, 2947.
(15) Weir, N. A.; Whiting, K. J . Polym. Sci., Part A: Polym. Chem.
1987, 25, 3459.

A 1:1 Ru-o-Acetylstyrene Complex
Organometallics, Vol. 17, No. 4, 1998 587
F igu r e 5.
Ta ble 1. Dim en sion s for th e 1:1 Com p lex of
o-Acetylstyr en e a n d
Ca r bon ylbis(tr ip h en ylp h osp h in e)r u th en iu m
space group
P21/c
a
b
c
â
19.421(1) Å
10.715(1) Å
19.495(6) Å
107.62(3)°
3866.5 Å3
vol.
Ta ble 2. Im p or ta n t Bon d Dista n ces (Å) a n d An gles
(d eg) for th e 1:1 Com p lex of o-Acetylstyr en e a n d
Ca r bon ylbis(tr ip h en ylp h osp h in e)r u th en iu m
Bond Distances
Ru-C1
Ru-C2
Ru-C3
Ru-O1
1.79(1)
Ru-P1
Ru-P2
C2-C3
2.333(2)
2.352(2)
1.43(1)
2.121(8)
2.167(9)
2.130(6)
F igu r e 6. 1H NMR of the ruthenium π-coordinated C-C
Angles
double bond.
C1-Ru-C2
O1-Ru-C1
C3-Ru-C2
P1-Ru-C1
P1-Ru-O1
P2-Ru-C1
P2-Ru-O1
P2-Ru-P1
Ru-C3-C2
92.4(3)
172.3(3)
38.9(0.3)
96.0(3)
82.1(2)
88.6(3)
99.1(2)
109.63(8)
68.8(5)
O1-Ru-C2
C3-Ru-C1
C3-Ru-O1
P1-Ru-C2
P1-Ru-C3
P2-Ru-C2
P2-Ru-C3
Ru-C2-C3
81.1(3)
92.9(4)
84.6(3)
106.6(2)
144.8(2)
143.5(2)
104.6(2)
72.3(5)
) 9.7 Hz). 31P NMR (CDCl3, 145.78 ΜΗz) δ: 46.21 (d, 1P,
J P-P ) 7.5 Hz), 46.78 (d, 1P, J P-P ) 7.5 Hz). IR (ν): 3076,
3057, 2858, 1896, 1684, 1653, 1559, 1436, 1163, 745, 697 cm-1
.
UV λmax nm (ꢀ): 500 (2.2 × 103), 336 (9.3 × 103 ). Anal. Calcd
for C47H40O2P2Ru: C, 70.58; H, 5.04; P, 7.74; Ru, 12.64.
Found: C, 71.13; H, 5.14; P, 6.17; Ru, 12.65.
1:1 Com p lex of o-P r op ion ylstyr en e a n d Ca r bon ylbis-
(tr ip h en ylp h osp h in e)r u th en iu m . Prepared in an analo-
gous manner to the method described above, mp 200-202 °C.
1H NMR (C6D6, 250 MHz) δ: -0.13 (ddd, 1H, J H-H ) 9 and 3.4
Hz, J H-P ) 4.3 Hz), 0.345 (t, 3H, J H-H ) 7.5 Hz), 2.01 (sept of
t, 2H, J H-H ) 7.5 Hz, J H-P ) 1.8 Hz), 3.67 (ddd, 1H, J H-H ) 7
and 3.4 Hz, J H-P ) 6 Hz), 4.25 (dddd, 1H, J H-H ) 9 and 7 Hz,
J H-P ) 3.4 and 1.8 Hz), 6.49 (t, 1H, J ) 7.4 Hz), 6.83-6.98
(m, 11H), 7.02-7.05 (m, 9H), 7.14-7.22 (m, 7H), 7.34-7.61
(m, 6H). 13C NMR (C6D6, 125.77 MHz) δ: 10.30, 32.16, 43.00
(dd, 1C, J C-P ) 28.8 and 7.3 Hz), 52.11 (dd, 1C, J C-P ) 25.1
and 14.7 Hz), 119.25, 127.75, 127.87, 127.93, 128.23, 128.73,
128.75, 129.05, 129.08, 130.35, 132.31, 133.43, 133.52, 134.19,
134.29, 138.47 (dd, 3Cipso, J C-P ) 32.44 and 1.1 Hz), 139.58
with benzene as the eluent. Dry toluene (5 mL) was added.
Argon was bubbled through the toluene solution for 15 min.
Freshly distilled styrene (58 µL, 0.5 mmol) was added by
injection. The solution was heated to 120 °C for 1 h. After
the mixture was cooled to room temperature, a solution of
o-acetylstyrene (73 mg, 0.5 mmol) in 5 mL of dry toluene was
added by syringe. The mixture was heated at 120 °C for 2 h.
A deep-brown-colored solution was obtained. All volatiles were
removed by evaporation under vacuum. The solid was dis-
solved in a minimum amount of toluene. Addition of ether
caused the precipitation of a very finely divided solid. The
supernatant solution was removed by syringe. The solid was
recrystallized from 10 to 15 mL of a mixture of toluene, ether
and pentane 1:10:5. In this way, an 81% yield (323 mg, 0.4
mmol) of the 1:1 complex, mp 184-185 °C, was obtained.
1H NMR (C6D6, 250 MHz) δ: 0.126 (ddd, 1H, J H-H ) 10.1
and 3.1 Hz, J P-H ) 4.7 Hz), 1.53 (dd, 3H, J P-H ) 1.8 Hz), 3.75
(ddd, 1H, J H-H ) 8.5 and 3.1 Hz, J P-H ) 5.8 Hz), 4.40 (dddd,
1H, J H-H ) 10.1 and 8.5 Hz, J P-H ) 5.0 and 2.2 Hz), 6.49 (t,
1H, J ) 6.8 Hz), 6.88 (d, 2H, J ) 7.2 Hz), 6.91 (td, 6H, J ) 6.8
and 1.4 Hz), 6.98 (td, 3H, J ) 7.6 and 1.4 Hz), 7.09 (dd, 9H, J
) 3.6 Hz, J P-H ) 1.8 Hz), 7.22 (d, 1H, J ) 6.8 Hz), 7.24 (dt,
(dd, 3Cipso, J C-P ) 34.2 and 2.8 Hz), 154.18 (t, 1Cipso, J C-P
1.2 Hz), 200.89 (t, 1C, J C-P ) 3.4 Hz), 210.98(t, 1C, J C-P
)
)
11.4 Hz). 31P NMR (C6D6, 202.47 MHz) δ: 45.29 (d, 1P, J P-P
) 9 Hz), 45.36 (d, 1P, J P-P ) 9 Hz). IR, ν: 3053, 1894, 1575,
1478, 1433, 1204, 1160, 743, 696 cm-1. UV λmax nm (ꢀ): 500
(2.1 × 103), 337 (8.4 × 103). Anal. Calcd for C48H42O2P2Ru:
C, 70.84; H, 5.20; P, 7.61; Ru, 12.42. Found: C, 70.81; H, 5.13;
P, 8.46; Ru, 11.53.
Copolym er ization of Acetoph en on e an d 1,3-Divin yltet-
r a m eth yld isiloxa n e by th e 1:1 Com p lex of o-Acetylsty-
r en e a n d Ca r bon ylbis(tr ip h en ylp h osp h in e)r u th en iu m .
Copoly(2-acetyl-1,3-phenylene/3,3,5,5-tetramethyl-4-oxa-3,5-
disila-1,7-heptanylene) has been previously prepared by the
reaction of acetophenone and 1,3-divinyltetramethyldisiloxane
catalyzed by dihydridocarbonyltris(triphenylphosphine)ru-
thenium, which has been activated by treatment with a
stoichiometric amount of styrene. For complete details of the
synthesis and characterization of this polymer, see ref 6.
Freshly distilled 1,3-divinyltetramethyldisiloxane (1.00 g,
5.4 mmol), acetophenone (0.645 g, 5.4 mmol), and the 1:1
complex of o-acetylstyrene and carbonylbis(triphenylphos-
phine)ruthenium (70 mg, 0.088 mmol) were placed in an Ace
6H, J P-H ) 8.5, J ) 1.8 Hz), 7.71(ddd, 6H, J P-H ) 9, J H-H
)
5.5 and 3.0 Hz). Both 1H and 31P decoupling experiments
establish the magnitude of the coupling constants between the
vinyl hydrogens and between the vinyl hydrogens and phos-
phorus (Figure 6).
13C NMR (CDCl3, 90.57 MHz) δ: 25.90, 40.90 (dd, 1C, J C-P
) 24.6 and 3.1 Hz), 50.44 (dd, 1C, J C-P ) 15.5 and 4.7 Hz),
119.06, 127.33, 127.44, 127.54, 127.88, 128.27, 128.30, 128.65,
128.68, 130.66, 132.17, 132.88, 133.04, 133.58, 133.71, 137.46
(d, Cipso, J C-P ) 28.18 Hz), 138.83 (dd, 3Cipso, J C-P ) 30.7 and
2.4 Hz), 153.57 (t, 1Cipso, J C-P ) 2.8 Hz), 195.85 (t, CCdO, J C-P
) 3.4 Hz), 211.03 (t, CCdO, J C-P ) 11.9 Hz). 31P NMR (C6D6,
109.35 ΜΗz) δ: 46.64 (d, 1P, J P-P ) 9.7 Hz), 46.96 (d, 1P, J P-P

588 Organometallics, Vol. 17, No. 4, 1998
Lu et al.
pressure tube with 1.5 mL of dry toluene. Argon gas was
bubbled through the mixture for 2 min. The pressure tube
was sealed and was heated to 120-140 °C for 50 h. The
reaction mixture was precipitated 3 times from THF by
addition of methanol. In this way, 0.85 g (∼50% yield) of
copoly(2-acetyl-1,3-phenylene/3,3,5,5-tetramethyl-4-oxa-3,5-
disila-1,7-heptanylene) Mw/Mn ) 9230/6560 was obtained. The
1H and 13C NMR spectra of the copolymer were in complete
agreement with that previously obtained.4,6
Copolym er iza tion of Acetop h en on e a n d 1,3-d ivin yltet-
r a m eth yld isiloxa n e by th e 1:1 Com p lex of o-P r op r ion yl-
styr en e an d Car bon ylbis(tr iph en ylph osph in e)r u th en iu m.
This was carried out in an analogous manner to that described
above. In this way, 1.00 g (∼61% yield) of copolymer Mw/Mn
) 8730/6760 was obtained, whose spectral properties were in
agreement with those previously reported.6
acetylstyrene is added to a solution of activated ruthe-
nium catalyst, why does a 1:1 complex form rather than
a high molecular weight polymer? Murai has proposed
that the first step in the reaction involves coordination
of the catalytically active unsaturated ruthenium com-
plex to the oxygen of the carbonyl group. Our X-ray
structure confirms the presence of a strong Ru-O bond.
Apparently, however, in the case of o-acetylstyrene, the
carbonyl-complexed unsaturated ruthenium center pre-
fers to coordinate to the adjacent C-C double bond
rather than to insert into the ortho C-H bond.
Ack n ow led gm en t. This work was supported in part
by the National Science Foundation and by the Air
Force Office of Scientific Research. J yri Paulasaari
thanks the Neste Foundation for fellowship support.
Con clu sion
Su p p or tin g In for m a tion Ava ila ble: Tables giving crys-
tal data and refinement details, positional and thermal
parameters, and bond distances and angles (9 pages). Order-
ing information is given on any current masthead page.
While these experiments have provided additional
insight into the dihydridocarbonyltris(triphenylphos-
phine)ruthenium-catalyzed reactions of acetophenone
with vinyl silane systems, many questions remain
unanswered. When a stoichiometric amount of o-
OM9708541