Palladium- and platinum-catalyzed reactions of benzo[1,2:4,5]bis(1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene) with alkenes

Article abstract of DOI:10.1016/S0022-328X(99)00236-3

The palladium-catalyzed reaction of benzo[1,2:4,5]bis(1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene) (1) with styrene in refluxing benzene afforded two regioisomers of 1:2 adducts, benzo[1,2](1,1,4,4-tetraethyl-2-phenyl-1,4-disilacyclohex-4-ene)[4,5](1,1,4,

Full text of DOI:10.1016/S0022-328X(99)00236-3

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 587 (1999) 1–8
Palladium- and platinum-catalyzed reactions of
benzo[1,2:4,5]bis(1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene) with
alkenes
Akinobu Naka a, Kyung Koo Lee a, Kazunari Yoshizawa b, Tokio Yamabe b,c,
Mitsuo Ishikawa a,*
a Department of Chemical Technology, Kurashiki Uni6ersity of Science and the Arts, 2640 Nishinoura, Tsurajima-cho, Kurashiki,
Okayama 712-8505, Japan
b Department of Molecular Engineering, Kyoto Uni6ersity, Sakyo-ku, Kyoto 606-8501, Japan
c Institute for Fundamental Chemistry, 34-4 Takano-Nishihiraki-cho, Sakyo-ku, Kyoto 606-8103, Japan
Received 24 February 1999; received in revised form 26 April 1999
Abstract
The palladium-catalyzed reaction of benzo[1,2:4,5]bis(1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene) (1) with styrene in refluxing
benzene afforded two regioisomers of 1:2 adducts, benzo[1,2](1,1,4,4-tetraethyl-2-phenyl-1,4-disilacyclohex-4-ene)[4,5](1,1,4,4-te-
traethyl-3-phenyl-1,4-disilacyclohex-4-ene) and benzo[1,2:4,5]bis(1,1,4,4-tetraethyl-2-phenyl-1,4-disilacyclohex-4-ene), whose iso-
mers consist of cis and trans in a ratio of 1:1 in 91% combined yield. Similar reaction of 1 with 1-hexene gave two regioisomers
involving cis and trans isomers in 89% combined yield. With ethylene, 1 produced benzo[1,2:4,5]bis(1,1,4,4-tetraethyl-1,4-disilacy-
clohex-5-ene) (8) in 70% yield, together with a 15% yield of a 2:3 adduct. The platinum-catalyzed reaction of 1 with styrene gave
a 1:1 mixture of cis- and trans-benzo[1,2:4,5]bis(2-benzyl-1,1,3,3-tetraethyl-1,3-disilacyclopent-4-ene) in 90% yield. Similar
treatment of 1 with 1-hexene produced cis- and trans-benzo[1,2:4,5]bis(1,1,3,3-tetraethyl-2-pentyl-1,3-disilacylopent-4-ene) in a
ratio of 1:1 in 92% yield, while with ethylene, 1 afforded 8 as a main product, in addition to two types of 1:2 adduct as minor
products. © 1999 Elsevier Science S.A. All rights reserved.
Keywords: Benzobis(disilacyclobutene); Catalyzed reaction; Palladium; Platinum
1. Introduction
bond into a silicon–silicon bond in the benzodisilacy-
clobutene [6,7].
3,4-Benzo-1,1,2,2-tetraethyl-1,2-disilacyclobut-3-ene
shows unique chemical behavior [1]. The thermolysis of
this compound produces an o-quinodisilane [2], while
its photolysis proceeds to give 1-ethyl-1-(2-diethylsi-
lylphenyl)-1-silaprop-1-ene, as a reactive species [3]. The
benzodisilacyclobutene readily reacts with organic
molecules such as aromatic compounds, carbonyl com-
pounds, alkenes, and alkynes in the presence of a
catalytic amount of the transition-metal complexes to
give various types of products [1,4,5]. The palladium-
and platinum-catalyzed reactions of the benzodisilacy-
clobutene with diphenylacetylene and 3-hexyne afford
the respective adducts arising from insertion of a triple
The palladium-catalyzed reactions of the benzodisila-
cyclobutene with styrene and 1-hexene produce the
corresponding adducts formed from insertion of a car-
bon–carbon double bond into a silicon–silicon bond in
the starting compound [8]. The platinum-catalyzed re-
actions with olefins, however, proceed in a different
fashion from that of the palladium-catalyzed reactions.
They afford the reactive products derived from terminal
sp2 CꢀH bond activation of olefins [9].
Recently, we synthesized benzo[1,2:4,5]bis(1,1,2,2-te-
traethyl-1,2-disilacyclobut-3-ene) (1) and found that
this compound readily reacts with alkynes in the pres-
ence of a catalytic amount of a palladium(0) or plat-
inum(0) catalyst to give the respective 1:2 adducts
arising from insertion of a triple bond into silicon–sili-
con bonds in the starting benzobis(disilacyclobutene) 1
in high yields [10].
* Corresponding author. Tel.: +81-864401086; fax: +81-86-
84401062.
E-mail address: mishika@chem.kusa.ac.jp (M. Ishikawa)
0022-328X/99/$ - see front matter © 1999 Elsevier Science S.A. All rights reserved.
PII: S0022-328X(99)00236-3

2
A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
Scheme 1.
In order to learn more about the chemical behavior
The 13C-NMR spectrum displayed two resonances at
11.29 and 13.10 ppm, two resonances at 135.45 and
154.71 ppm, and four resonances at 128.37, 128.85,
134.38 and 137.97 ppm, due to ethyl carbons,
phenylene ring carbons, and phenyl ring carbons,
respectively.
of the benzobis(disilacyclobutene) [11,12], we have in-
vestigated the palladium- and platinum-catalyzed reac-
tions of 1 with alkenes.
2. Results and discussion
Next we carried out the palladium- and platinum-cat-
alyzed reactions of 1 with terminal olefins. Thus, treat-
ment of 1 with 3.8 equivalents of styrene in the presence
of 5 mol% of tetrakis(triphenylphosphine)palladium(0)
in benzene afforded 1:2 adducts consisting of two re-
gioisomers in a ratio of 1:1, in which each regioisomer
involves geometric isomers, cis and trans isomers in a
ratio of approximately 1:1, in 91% combined yield.
GLC analysis of the reaction mixture showed a homo-
geneous peak. All attempts to separate regioisomers or
geometric isomers were unsuccessful. In all cases, the
mixture consisting of the same ratio of isomers was
obtained. However, the structures of the isomers were
identified as two pairs of cis and trans isomers of
benzo[1,2](1,1,4,4-tetraethyl-2-phenyl-1,4-disilacyclo-
hex-4-ene)[4,5](1,1,4,4-tetraethyl-3-phenyl-1,4-disila-
cyclohex-4-ene) (4) and benzo[1,2:4,5]bis(1,1,4,4-tetra-
ethyl-2-phenyl-1,4-disilacyclohex-4-ene) (5) (Scheme 2).
First, we examined the stoichiometric reaction of
benzobis(disilacyclobutene) 1 with a palladium(0) com-
plex, and a mono- and dipalladium insertion product
could be prepared in a sealed NMR tube. Thus, the
reaction of
1 with one equivalent of tetrakis(t-
riphenylphosphine)palladium(0) at room temperature in
deuteriobenzene in a sealed NMR tube gave a palla-
dium insertion product (2), formed from insertion of a
palladium species into one silicon–silicon bond in the
starting compound 1, as the sole product (Scheme 1). In
this reaction, no product arose from insertion of two
palladium species into both silicon–silicon bonds in 1.
As expected, the 29Si-NMR spectrum of the reaction
mixture showed two resonances at 6.70 and 44.86 ppm,
due to the silicon atoms in the disilacyclobutene ring
and the silicon atoms in the palladadisilacyclopentene
ring, respectively. Its 13C-NMR spectrum indicated four
signals at 6.29, 9.34, 11.22 and 12.87 ppm, attributed to
two different kinds of ethyl carbons, and three signals
at 135.90, 153.56 and 157.53 ppm, due to phenylene
ring carbons, as well as four signals at 128.44, 129.13,
134.44 and 137.14 ppm, which are attributable to
phenyl ring carbons. Addition of styrene to the deuteri-
obenzene solution of 2 gave two isomers of 1:2 adducts
whose 29Si-NMR spectrum revealed eight signals which
are identical to the chemical shifts of adducts 4 and 5
(see below). Similar reaction of 1 with two equivalents
of tetrakis(triphenylphosphine)palladium(0) afforded a
dipalladium complex (3) whose NMR spectra are con-
sistent with the proposed structure. Thus, the 29Si-
NMR spectrum revealed a single resonance at 43.86
ppm, attributed to four equivalent ring silicon atoms.
1
The H-NMR spectrum for the mixture of 4 and 5
revealed a single resonance at 7.66 ppm due to the
phenylene ring proton of regioisomer 4, and two reso-
nances at 7.62 and 7.69 ppm attributed to the
phenylene ring protons of regioisomer 5 with an inte-
gral ratio of 2:1:1. The 29Si-NMR spectrum for this
mixture showed eight resonances indicating that each
regioisomer consists of cis and trans isomers.
Similar palladium-catalyzed reaction of 1 with 1-hex-
ene in refluxing benzene again gave two regioisomers 6
and 7 in the ratio of 1:1 in 89% combined yields. Again,
each regioisomer was shown to be a mixture consisting
of cis and trans in the ratio of 1:1 by NMR spectromet-
ric analysis. Unfortunately, all attempts to isolate each
regioisomer from the mixture using recycling gel perme-
ation chromatography (GPC) were unsuccessful.

A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
3
Scheme 2.
Scheme 3.
a palladium–silicon bond to give complex 10. Since 1:1
adducts could not be detected in the present reactions,
reductive elimination to produce free palladium species
from complex 10 would not be involved. The palladium
species that was eliminated from 10 presumably inter-
acts with the 1:1 adduct thus formed, giving a complex
such as 11, and would insert into a silicon–silicon bond
in this species to give complex 12. Finally the reaction
of complex 12 with olefins affords the 1:2 adduct as
shown in Scheme 3.
The formation of the 1,2,5,8-tetrasilacyclodeca-3,9-
diene ring in 9 may be understood in terms of the
reaction of a 3,4-benzo-2,5-disila-1-palladacyclohept-3-
ene intermediate with a benzodisilacyclobutene deriva-
tive as shown in Scheme 4. Indeed, we have found that
such a type of compound was formed in the reaction of
the palladium-catalyzed reaction of 3,4-benzo-1,1,2,2-
tetraethyl-1,2-disilacyclobut-3-ene with ethylene [8].
The platinum-catalyzed reaction of 1 with olefins
proceeded to give different types of products from
those of the palladium-catalyzed reactions. Treatment
of 1 with styrene in the presence of a catalytic amount
of (h2-ethylene)bis(triphenylphosphine)platinum(0) in
refluxing benzene gave a 1:1 mixture of cis- and trans-
benzo[1,2:4,5]bis(2-benzyl-1,1,3,3-tetraethyl-1,3-disila-
The reaction of 1 with ethylene in the presence of the
palladium catalyst proceeded in a different fashion
from the reactions with styrene and 1-hexene. When
ethylene gas was introduced into a benzene solution of
1 at room temperature, benzo[1,2:4,5]bis(1,1,4,4-te-
traethyl-1,4-disilacyclohex-5-ene) (8) was obtained in
78% yield, in addition to a 15% yield of a 2:3 adduct,
2{bis(1,1,4,4-tetraethyl-2H,3H - 1,4-disila[3,4:9,10]naph-
tho}-1,1,2,2,5,5,8,8-octaethyl-1,2,5,8-tetrasilacyclodeca-
3,9-diene (9). Products 8 and 9 were readily isolated by
recycling GPC and their structures were confirmed by
spectrometric analysis, as well as by elemental analysis
(see Section 3).
We recently reported that the palladium- and plat-
inum-catalyzed reactions of 1 with alkynes afforded no
1:1 adduct, even in the early stages of the reaction [10].
Likewise, no 1:1 adduct was detected in the present
reactions, but in all cases the 1:2 adducts were ob-
tained. As can be seen in the stoichiometric reaction of
1 with tetrakis(triphenylphosphine)palladium, mono-
palladium complex 2 can be produced. Therefore, in the
catalytic reaction, presumably a complex 2 is initially
produced as a key intermediate. Olefin coordinates to
this palladium atom in complex 2, and then inserts into

4
A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
Scheme 4.
cyclopent-4-ene) (13) in 90% yield (Scheme 5). GLC
analysis of the reaction mixture revealed a homogenous
peak, and recycling GPC showed no separate peak.
Although the cis and trans isomers could not be sepa-
rated, the structures of the isomers were verified by
spectrometric analysis. The 13C-NMR spectrum for the
mixture showed two signals at 9.00 and 9.04 ppm due
to two kinds of carbon atoms in the disilacyclopent-4-
ene rings of the cis and trans isomers.
Treatment of 1 with 1-hexene in the presence of the
platinum catalyst under the same conditions produced
cis- and trans-benzo[1,2:4,5]bis(1,1,3,3-tetraethyl-2-
pentyl-1,3-disilacyclopent-4-ene) (14) in a ratio of 1:1 in
92% combined yield. Again, the two isomers could not
be separated by recycling GPC. The 29Si-NMR spec-
trum of the mixture showed two resonances at 12.39
and 12.42 ppm due to the silicon atoms of the cis and
trans, respectively.
The formation of 13 and 14 may be best explained in
terms of the terminal sp2 CꢀH bond activation as
shown in Scheme 6. In the platinum-catalyzed reac-
tions, platinum complex 15 would be produced as a
reactive species in the initial step. The sp2 CꢀH bond of
olefins probably adds to the platinum atom in complex
15, to give complex 16, which undergoes cleavage to
give the ring opened product 17. Intramolecular hy-
drosilylation of 17 would afford complex 18. Since no
1:1 adduct can be detected in the reaction mixture, the
platinum species which would be produced by reductive
elimination from the complex arising from addition of a
PtꢀH bond into the carbon–carbon double bond in
complex 17 would interact with a 1:1 adduct like 18.
Insertion of the platinum species in 18 into a silicon–
silicon bond gives complex 19 that reacts with olefins to
give the product. It was previously reported that the
platinum-catalyzed reactions of 3,4-benzo-1,1,2,2-te-
traethyl-1,2-disilacyclobut-3-ene with olefins produced
the
3,4-benzo-1,1,3,3-tetraethyl-1,3-disilacyclopent-4-
ene derivatives derived from sp2 CꢀH bond activation
[9].
Ethylene also reacts with 1 in the presence of a
platinum catalyst in refluxing benzene to give 1:2 ad-
ducts. However, the types of the products thus formed
are different from those of the reaction with styrene
and 1-hexene. Compound 8 and two types of com-
pounds, 20 and 21, which involve the silicon-containing
five-membered and six-membered ring in the molecule,
were obtained in 40, 15 and 10% yields, respectively
(Scheme 7), in addition to small amounts of uniden-
tified products (less than 3% each). Products 8, 20 and
21 were isolated by recycling GPC. All spectral data for
product 8 were identified with those of the authentic
sample. The structures of products 20 and 21 were
confirmed by mass and NMR spectrometric analysis as
well as elemental analysis (see Section 3). The forma-
tion of the methylenedisilacyclopentene ring in product
20 can be understood by elimination of platinum dihy-
dride species from the intermediate like 17 (R=H),
Scheme 5.

A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
5
Scheme 6.
Scheme 7.
while 21 can be explained by hydrosilylation of the
3. Experimental
similar intermediate.
In conclusion, the pattern of the present reaction was
found to be similar to that of the palladium- and
platinum-catalyzed reactions of 3,4-benzo-1,1,2,2-te-
traethyl-1,2-disilacyclobut-3-ene with olefins as previ-
ously reported. The palladium-catalyzed reaction of 1
with styrene and 1-hexene afforded 1:2 adducts arising
from insertion of a carbon–carbon double bond into
two silicon–silicon bonds in 1 in high yields. Similar
reaction with ethylene gave benzo[1,2:4,5]bis(1,4-disila-
cyclohex-5-ene) as a main product in addition to a 2:3
adduct as a minor product. The platinum-catalyzed
reactions of 1 with styrene and 1-hexene gave 1:2
adducts derived from the terminal sp2 CꢀH bond acti-
vation of olefins in excellent yields. With ethylene, 1
produced a 1:2 adduct formed from insertion of a
carbon–carbon double bond into the silicon–silicon
bonds in the starting compound 1.
3.1. General procedure
All platinum- and palladium-catalyzed reactions of
compound 1 with alkenes were carried out under a
nitrogen atmosphere. Yields of the products with one
exception, compound 9, were determined by analytical
GLC with the use of pentadecane as an internal stan-
dard on the basis of the starting compounds used.
NMR spectra were recorded on a Jeol model JNM-
LA300 spectrometer and JNM-LA500 spectrometer.
Infrared spectra were recorded on a Jeol model JIR-Di-
amond20 IR spectrophotometer. Low-resolution mass
spectra were measured on a Jeol model JMS-700 instru-
ment. GPC separation was performed with a Model
LC-908 Recycling Preparative HPLC (Japan Analytical
Industry).

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A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
3.2. Stoichiometric reaction of 1 with
tetrakis(triphenylphosphine)palladium(0)
(4C), 146.96 (4C) (phenyl ring carbons), 139.37 (2C),
139.75 (2C), 140.12 (2C), 141.60 (2C), 141.74 (2C), 142.52
(2C), 142.69 (2C) (phenylene ring carbons). 29Si-NMR:
l(CDCl3) −1.80, −1.78, −1.71 (2Si), −1.68, −1.65,
−1.62 (2Si). Anal. Calc. for C38H58Si4: C, 72.77; H, 9.32.
Found: C, 72.56; H, 9.29.
A mixture of 1 (0.0367 g, 0.0876 mmol) and tetrakis-
(triphenylphosphine)palladium(0) (0.0974 g, 0.0843
mmol) was placed in an NMR tube with a rubber septum
cap. The tube was allowed to stand at room temperature
for 1 h to give 2. 1H-NMR: l(CDCl3) 0.50–1.31 (m, 40H,
EtSi), 7.00–7.80 (m, 62H, phenyl and phenylene ring
protons). 13C-NMR: l(CDCl3) 6.29, 9.34, 11.22, 12.87
(EtSi), 135.90, 153.56, 157.53 (phenylene ring carbons),
128.44 (3JCꢀP=7.4 Hz), 129.13, 134.44 (2JCꢀP=17.1 Hz),
137.14 (1JCꢀP=5.0 Hz) (phenyl ring carbons). 29Si-
NMR: l(CDCl3) 6.70, 44.86.
3.5. Reaction of 2 with styrene
A mixture of 1 (0.0325 g, 0.0776 mmol) and tetrakis-
(triphenylphosphine)palladium(0) (0.0897 g, 0.0776
mmol) was placed in an NMR tube with a rubber septum
cap. The tube was allowed to stand at room temperature
(r.t.) for 1 h. The 13C- and 29Si-NMR spectra revealed
the presence of 2 as the sole product. Styrene (0.0201 g,
0.193 mmol) was added and then the mixture was heated
at 80°C for 20 min. The 29Si-NMR spectrum of this
solution revealed eight resonances whose chemical shifts
are identical with those of 4 and 5.
3.3. Reaction of 1 with two equi6alents of
tetrakis(triphenylphosphine)palladium(0)
A mixture of 1 (0.0095 g, 0.0267 mmol) and tetrakis-
(triphenylphosphine)palladium(0) (0.0702 g, 0.0607
mmol) was placed in an NMR tube with a rubber septum
cap. The tube was allowed to stand at room temperature
for 1 h to give 3. 1H-NMR: l(CDCl3) 0.53–1.27 (m, 40H,
EtSi), 6.96–7.88 (m, 122H, phenyl and phenylene ring
protons). 13C-NMR: l(CDCl3) 11.29, 13.10 (EtSi),
3.6. Reaction of 1 with 1-hexene in the presence of a Pd
complex
A mixture of 0.0808 g (0.193 mmol) of 1, 0.0503 g
(0.599 mmol) of 1-hexene, and 0.0118 g (0.0102 mmol)
of tetrakis(triphenylphosphine)palladium(0) in 3 ml of
dry benzene was placed in a 30-ml two-necked flask fitted
with a stirrer and reflux condenser. The mixture was
heated to reflux for 12 h and passed through a short silica
gel column. The mixture was analyzed by GLC as being
6 and 7 (89% combined yield). A mixture of 6 and 7 was
isolated by column chromatography. The ratio of the
isomers was calculated to be approximately 1:1 by
1H-NMR spectrometric analysis. MS: m/z 586 (M+). IR:
2954, 2910, 2873, 1457, 1413, 1376, 1232, 1149, 1093,
135.45, 154.71(phenylene ring carbons), 128.37 (3JCꢀP
8.3 Hz), 128.85, 134.38 (2JCꢀP=17.6 Hz), 137.97 (1JCꢀP
=
=
7.2 Hz) (phenyl ring carbons). 29Si-NMR l(CDCl3)
43.86.
3.4. Reaction of 1 with styrene in the presence of a Pd
complex
A mixture of 0.0721 g (0.172 mmol) of 1, 0.0680 g
(0.653 mmol) of styrene, and 0.0101 g (0.00874 mmol) of
tetrakis(triphenylphosphine)palladium(0) in 3 ml of dry
benzene was placed in a 30-ml two-necked flask fitted
with a stirrer and reflux condenser. The mixture was
stirred at room temperature for 2 h and passed through
a short silica gel column. The mixture was analyzed by
GLC as being 4 and 5 (91% combined yield). A mixture
of 4 and 5 was isolated by column chromatography. The
ratio of the isomers was calculated to be approximately
1
1014, 956, 788, 715, 609 cm−1. H-NMR: l(CDCl3)
0.63–1.67 (m, 256H, EtSi, CH2, CHSi, n-Bu), 7.55 (s, 2H,
phenylene ring protons for 7), 7.56 (s, 4H, phenylene ring
protons for 6), 7.58 (s, 2H, phenylene ring protons for
7). 13C-NMR: l(CDCl3) 3.35 (2C), 3.38 (2C), 3.57 (2C),
3.59, 3.60, 5.20, 5.22, 5.27, 5.28, 6.05 (2C), 6.09 (2C),
7.46, 7.50 (2C), 7.51 (3C), 7.54 (2C), 7.78, 7.80, 7.82 (2C),
7.97, 8.00, 8.04 (2C) (EtSi), 10.45 (4C) (CH2), 16.64,
16.68, 16.72, 16.75 (CH), 14.16 (4C), 22.67 (4C), 30.25
(4C), 33.30 (4C) (n-Bu), 138.96 (2C), 139.19 (2C), 139.42
(2C), 142.09 (2C), 142.16 (2C), 142.64 (2C), 142.72 (2C)
(phenylene ring carbons). 29Si-NMR: l(CDCl3) −3.14
(2Si), −3.08 (2Si), −2.00 (2Si), −1.89 (2Si). Anal.
Calc. for C34H66Si4: C, 69.54; H, 11.33. Found: C, 69.54;
H, 11.30.
1
1:1 by H-NMR spectrometric analysis. MS: m/z 626
(M+). IR: 3012, 2950, 2871, 1596, 1492, 1457, 1413,
1234, 1149, 1016, 956, 769, 744, 698 cm−1. H-NMR:
1
l(CDCl3) 0.52–1.05 (m, 160H, EtSi), 1.29 (brs, 8H, CH),
1.61 (t, 8H, CHPh, J=15 Hz), 2.76 (d, 8H, CH, J=15
Hz), 7.14–7.33 (m, 40H, phenyl ring protons), 7.62 (s,
2H, phenylene ring protons for 5), 7.66 (s, 4H, phenylene
ring protons for 4), 7.69 (s, 2H, phenylene ring protons
for 5). 13C-NMR: l(CDCl3) 2.39, 2.43 (2C), 2.47, 2.82,
2.87 (2C), 2.90, 4.92 (2C), 4.99 (2C), 5.77 (2C), 5.80 (2C),
7.31 (2C), 7.34, 7.36, 7.49 (2C), 7.53 (2C), 7.57 (2C), 7.60,
7.63, 7.81, 7.83 (2C), 7.86 (EtSi), 11.65 (4C) (CH2), 26.30,
26.34, 26.43 (2C) (CH), 124.41 (4C), 126.98 (4C), 128.11
3.7. Reaction of 1 with ethylene in the presence of a
Pd complex
A mixture of 0.1539 g (0.367 mmol) of 1 and 0.0214
g (0.0185 mmol) of tetrakis(triphenylphosphine)palla-

A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
7
dium(0) in 5 ml of dry benzene was placed in a 30-ml
two-necked flask fitted with a inlet tube for ethylene gas
and reflux condenser. The ethylene gas was introduced
into the mixture at r.t. for 30 min. The solution was
then passed through a short silica gel column and
analyzed by GLC as being compound 8 (78%). Com-
pounds 8 and 9 (isolated yield 15%) were isolated by
recycling GPC. For 8—MS: m/z 474 (M+). IR: 2952,
2906, 2871, 1456, 1413, 1232, 1149, 1093, 1006, 956,
of (h2-ethylene)bis(triphenylphosphine)platinum(0) in 3
ml of dry benzene was placed in a 30-ml two-necked
flask fitted with a stirrer and reflux condenser. The
mixture was heated to reflux for 30 min, and then
passed through a short silica gel column to remove the
platinum species. Compound 14 was isolated by silica
gel column chromatography (92% yield). M.p. 62–
64°C. MS: m/z 586 (M+). IR: 2954, 2871, 1457, 1413,
1376, 1232, 1114, 1016, 960, 775, 754, 707, 615 cm−1
.
739, 711 cm−1 1H-NMR: l(CDCl3) 0.73 (q, 16H,
.
1H-NMR: l(CDCl3) 0.456 (t, 2H, CHSi, J=7.6 Hz),
0.459 (t, 2H, CHSi, J=7.6 Hz), 0.61–1.01 (m, 80H,
EtSi), 1.29–1.38 (m, 28H, CH2, CH3), 1.45 (quint, 8H,
CH2CH2CH2, J=7.6 Hz), 1.63 (q, 8H, CHCH2CH2,
J=7.6 Hz), 7.69 (s, 4H, phenylene ring protons). 13C-
NMR: l(CDCl3) 5.05 (2C), 6.01, 6.04, 6.84 (2C), 7.68
(2C), 7.73, 7.75 (EtSi), 14.17 (2C) (CH3), 22.64 (2C),
25.35 (2C), 32.15 (2C), 34.38 (2C) (CH2), 137.31 (2C),
147.65(2C) (phenylene ring carbons). 29Si-NMR:
l(CDCl3) 12.39, 12.42. Anal. Calc. for C34H66Si4: C,
69.54; H, 11.33. Found: C, 69.68; H, 11.45.
CH2Si, J=7.6 Hz), 0.95 (t, 24H, CH3, J=7.6 Hz), 1.00
(s, 8H, CH2), 7.53 (s, 2H, phenylene ring protons).
13C-NMR: l(CDCl3) 3.47 (CH2), 5.18, 7.63 (EtSi),
139.14, 142.71 (phenylene ring carbons). 29Si-NMR:
l(CDCl3) −3.99. Anal. Calc. for C26H50Si4: C, 65.74;
H, 11.03. Found: C, 65.58; H, 10.94. For 9—MS: m/z
891 (M+ −Et). IR: 2954, 2906, 2871, 1456, 1415, 1234,
1160, 1130, 1085, 1051, 1002, 711 cm−1 1H-NMR:
.
l(CDCl3) 0.66–1.01 (m, 92H, EtSi, CH2), 7.60 (s, 2H,
phenylene ring protons), 7.77 (s, 2H, phenylene ring
protons). 13C-NMR: l(CDCl3) 3.27, 3.60 (CH2), 5.13
(2C), 5.33, 6.36, 7.67, 7.75, 7.86, 8.21 (EtSi), 141.37,
141.85, 141.96, 142.09, 142.14, 142.17 (phenylene ring
carbons). 29Si-NMR: l(CDCl3) −12.39, −4.00, −
3.69, 4.13. Anal. Calc. for C50H96Si8: C, 65.14; H,
10.49. Found: C, 65.17; H, 10.73.
3.10. Reaction of 1 with ethylene in the presence of a
Pt complex
A mixture of 0.3570 g (0.852 mmol) of 1 and 0.0215
g (0.00288 mmol) of (h2-ethylene)(triphenylphosphine)-
platinum(0) in 5 ml of dry benzene was placed in a
30-ml two-necked flask fitted with a inlet tube for
ethylene gas and reflux condenser. The ethylene gas was
introduced into the mixture at 80°C for 30 min. The
solution was then passed through a short silica gel
column and analyzed by GLC as being compound 9
(40%), 20 (15%) and 21(10%). Compound 9, 20 and 21
were isolated by recycling GPC. All spectral data for 9
were identical with those of an authentic sample. For
20—MS: m/z 472 (M+). IR: 2954, 2871, 1596, 1456,
3.8. Reaction of 1 with styrene in the presence of a Pt
complex
A mixture of 0.1197 g (0.286 mmol) of 1, 0.1005 g
(0.966 mmol) of styrene, and 0.0103 g (0.0138 mmol) of
(h2-ethylene)bis(triphenylphosphine)platinum(0) in 3 ml
of dry benzene was placed in a 30-ml two-necked flask
fitted with a stirrer and reflux condenser. The mixture
was heated to reflux for 30 min, and then passed
through a short silica gel column to remove the plat-
inum species. Compound 13 was isolated by silica gel
column chromatography (90% yield). M.p. 176–178°C.
MS: m/z 626 (M+). IR: 3021, 2950, 2869, 1600, 1492,
1415, 1376, 1232, 1132, 1016, 960, 786, 719 cm−1
.
1H-NMR: l(CDCl3) 0.66–1.00 (m, 44H, EtSi, CH2),
6.60 (s, 2H, olefinic protons), 7.65 (s, 2H, phenylene
ring protons). 13C-NMR: l(CDCl3) 3.47 (CH2), 5.23,
5.86, 7.62 (2C) (EtSi), 138.43, 141.10, 143.31, 143.61,
146.74 (phenylene ring and olefinic carbons). 29Si-
NMR: l(CDCl3) −3.68, 0.15. Anal. Calc. for
C26H48Si4: C, 66.02; H, 10.23. Found: C, 65.97; H,
10.17. For 21—MS: m/z 474 (M+). IR: 2954, 2912,
2877, 1457, 1415, 1376, 1232, 1132, 1091, 1016, 958,
1
1454, 1411, 1234, 1112, 958, 767, 744, 696 cm−1. H-
NMR: l(CDCl3) 0.46–0.89 (m, 84H, EtSi, CH), 2.84
(d, 8H, CH2Ph, J=8.2 Hz), 7.06–7.22 (m, 20H, phenyl
ring protons), 7.55 (s, 4H, phenylene ring protons).
13C-NMR: l(CDCl3) 5.25 (2C), 5.41, 5.45, 7.37 (2C),
7.69 (2C) (EtSi), 9.00, 9.04 (CH), 31.03 (2C) (CH2),
125.68, 128.13, 128.23, 137.48, 145.09, 147.33 (phenyl
and phenylene ring carbons). 29Si-NMR: l(CDCl3)
12.30. Anal. Calc. for C38H58Si4: C, 72.77; H, 9.32.
Found: C, 72.50; H, 9.45.
1
784, 715 cm−1. H-NMR: l(CDCl3) 0.36 (q, 1H, HC,
J=7.6 Hz), 0.58–1.02 (m, 44H, EtSi, CH2), 0.18 (d,
3H, Me, J=7.6 Hz), 7.61 (s, 2H, phenylene ring pro-
tons). 13C-NMR: l(CDCl3) −1.67 (CH), 4.25, 5.24,
5.56, 7.62 (EtSi), 8.68 (Me), 138.35, 147.18, 149.22
(phenylene ring and olefinic carbons). 29Si-NMR:
l(CDCl3) −3.68, 13.41. Anal. Calc. for C26H50Si4: C,
65.74; H, 11.03. Found: C, 65.87; H, 11.17.
3.9. Reaction of 1 with 1-hexene in the presence of a Pt
complex
A mixture of 0.1752 g (0.419 mmol) of 1, 0.1201 g
(1.43 mmol) of 1-hexene, and 0.0143 g (0.0191 mmol)

8
A. Naka et al. / Journal of Organometallic Chemistry 587 (1999) 1–8
[3] H. Sakamoto, M. Ishikawa, Organometallics 11 (1992) 2580.
Acknowledgements
[4] A. Naka, S. Okazaki, M. Hayashi, M. Ishikawa, J.
Organomet. Chem. 499 (1995) 35.
This work was partially supported by Grant-in-Aid
for Scientific Research on Priority Areas (No.
10133257) from the Ministry of Education, Science,
Sports and Culture of Japan and by the fund of Re-
search for the Future Program (JSPS-PFTF96P00206),
to which our thanks are due. We also express our
appreciation to Toshiba Silicone, Sumitomo Electric
Industry, and Tokuyama for financial support.
[5] A. Naka, M. Hayashi, S. Okazaki, A. Kunai, M. Ishikawa,
Organometallics 15 (1996) 1101.
[6] A. Naka, T. Okada, M. Ishikawa, J. Organomet. Chem. 521
(1996) 163.
[7] A. Naka, T. Okada, A. Kunai, M. Ishikawa, J. Organomet.
Chem. 547 (1997) 149.
[8] A. Naka, M. Hayashi, S. Okazaki, M. Ishikawa, Organometal-
lics 13 (1994) 4994.
[9] M. Ishikawa, A. Naka, J. Ohshita, Organometallics 12 (1993)
4987.
[10] A. Naka, K. Yoshizawa, S. Kang, T. Yamabe, M. Ishikawa,
Organometallics 17 (1998) 5830.
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