Synthesis and reactions of poly[(ethoxysilylene)phenylenevinylene]s and chain-to-pendant energy transfer in the resulting polymer

Article abstract of DOI:10.1016/j.jorganchem.2006.03.021

Reactions of (bromophenylethenyl)diethoxysilanes with magnesium in THF gave poly[(ethoxysilylene)phenylenevinylene]s. The ethoxy group of the polymers could be readily replaced with other substituents by treating them with nucleophiles. Optical properties

Full text of DOI:10.1016/j.jorganchem.2006.03.021

Journal of Organometallic Chemistry 691 (2006) 3065–3070
www.elsevier.com/locate/jorganchem
Synthesis and reactions of poly[(ethoxysilylene)phenylenevinylene]s
and chain-to-pendant energy transfer in the resulting polymer
*
*
Joji Ohshita , Ryosuke Taketsugu, Koichi Hino, Atsutaka Kunai
Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan
Received 13 December 2005; received in revised form 10 March 2006; accepted 14 March 2006
Available online 18 March 2006
Abstract
Reactions of (bromophenylethenyl)diethoxysilanes with magnesium in THF gave poly[(ethoxysilylene)phenylenevinylene]s. The eth-
oxy group of the polymers could be readily replaced with other substituents by treating them with nucleophiles. Optical properties of the
resulting poly(silylenephenylenevinylene)s were examined with respect to their UV absorption and emission spectra. Of those, pyreny-
lethynyl-substituted one exhibited energy transfer from the backbone to the substituent in the photo-excited state.
ꢀ 2006 Elsevier B.V. All rights reserved.
Keywords: Polycarbosilane; Hydrosilation; Polymer reaction; Energy transfer
1. Introduction
[7]. In this paper, we report the synthesis of poly[(ethoxysil-
ylene)phenylenevinylene]s and their substitution reactions
with organic nucleophiles. Organosilylene-divinylarene
alternate polymers have been well studied very recently as
materials with unique optical properties [8,9]. However,
no papers concerning silylene-phenylenevinylene alternate
polymers have been published to date, in spite of the fact
that phenylenevinylene skeleton is often employed as a core
fragment of p-conjugated functionality materials. Optical
properties of the resulting silylene-phenylenevinylene poly-
mers also are described.
There has been an interest in polymers having an alter-
nate arrangement of an organosilanylene unit and a p-elec-
tron system [1,2]. In these polymers, the interaction
between the silicon r-orbital and the p-orbital (r–p conju-
gation) in the polymer backbone [1] and/or electron-donat-
ing properties of the silicon unit, which would elevate the
HOMO energy level of the p-electron system, allow to
use the polymers as p-type organic semi conductors for
electroluminescent devices [3] and thin film transistors [4].
It may be also noted that this type of the polymers are
usable as heat-resistant materials and preceramics with
high ceramic yield [5].
2. Results and discussion
Recently, we have demonstrated that synthesis of
poly[(ethoxysilylene)phenylene]s, followed by transforma-
tion of the Si–OEt bond by nucleophilic substitution, can
be a convenient method to prepare variously substituted
poly(silylenephenylene)s [6]. Indeed, utilizing this method,
we recently prepared poly(silylenephenylene)s bearing a
pendant fluorophor as highly photoluminescent materials
2.1. Monomer synthesis
We recently reported that palladium-catalyzed selective
dehydrogenation of trihydrosilanes with 2 equiv. of ethanol
produced diethoxyhydrosilanes in good yield [10]. With
diethoxyhydrosilanes thus prepared, we examined model
reactions for the preparation of monomers (Table 1). As
presented in Table 1, hydrosilation using the Wilkinson’s
catalyst proceeded most selectively to give the highest
trans/gem ratios among those examined. In most of the
*
Corresponding authors.
E-mail address: jo@hiroshima-u.ac.jp (J. Ohshita).
0022-328X/$ - see front matter ꢀ 2006 Elsevier B.V. All rights reserved.
doi:10.1016/j.jorganchem.2006.03.021

3066
J. Ohshita et al. / Journal of Organometallic Chemistry 691 (2006) 3065–3070
Table 1
Optimization of hydrosilation
CH2
H
C
catalyst
C Si(OEt)2R
H
PhC CH
+
C
RSi(OEt)2H
Si(OEt)2R
trans
gem
Catalyst
R
Solvent
Temperature
GC yield (%)
trans
gem
RSi(OEt)3
RhCl(PPh3)3
Hex
Ph
Ph
Toluene
Toluene
THF
r.t.
r.t.
r.t.
r.t.
83
76
49
67
2
1
48
29
7
6
0
2
Ph
Ether
H2PtCl66H2O/2-PrOH
IrCl(CO)(PPh3)2
Hex
Ph
Hex
Toluene
Ether
None
r.t.
r.t.
r.t.
15
71
60
34
19
32
33
9
4
Hex
THF
Reflux
41
21
10
reactions, triethoxysilanes were formed as the by-products.
Since the sterically less hindered trans-isomers seemed to be
more preferable as the monomers rather than the gem-iso-
mers, we carried out the following monomer synthesis by
using the Wilkinson’s catalyst in toluene at room
temperature.
Table 2 summarizes the results of the monomer synthe-
sis by hydrosilation of (bromophenyl)acetylene with dieth-
oxysilanes under the conditions as mentioned above. In
these reactions, triethoxysilanes were again found to be
formed, but they were readily removed by fractional distil-
lation. Carrying out the reaction at higher temperature led
to less selective formation of the trans-isomer. The mono-
mers were used for the following polymerization as the
trans/gem mixtures, since they could not be isolated.
such as ethers, chlorocarbons, and aromatic hydrocarbons.
Polymers 2a and 2c are soluble also in saturated hydrocar-
bons. However, for 2b, the high molecular weight fraction
is not soluble in pentane, and thus could be separated by
reprecipitation from chloroform/pentane (Table 3).
The polymer structures were verified mainly by the
NMR spectra. The trans/gem ratios (x/y) determined by
1
integration in the H NMR spectra are similar to those
of the monomers, indicating that non-chemoselective poly-
1
merization had occurred. The H and 13C NMR spectra
reveal only two sets of the ethoxy signals, due to the trans
and gem segments. Furthermore, the integration ratios are
almost consistent with the ideal structures. These results
clearly indicate that only one ethoxy group of the mono-
mers reacted during the polymerization to produce mono-
ethoxysilylene units, selectively, in the resulting polymer
backbone.
2.2. Synthesis and reactions of polymers
The ethoxy group on the silicon atom of the poly-
mers thus obtained was readily replaced with other
groups. As summarized in Table 4, the reactions of
polymer 2b with organic nucleophiles proceeded in
THF at room temperature. The reactions with 1 equiv.
of butyllithium and vinylmagnesium chloride afforded
When monomers 1a–1c were treated with an excess of
magnesium in refluxing THF and the resulting products
were reprecipitated from chloroform/ethanol, polymers
2a–2c were obtained, respectively, as shown in Table 3.
Polymers 2a–2c are soluble in common organic solvents,
Table 2
Monomer synthesis
R
Temperature
Product(trans/gem)a
Isolated yield (%)b
GC yield (%)
trans
gem
RSi(OEt)3
Hex
Ph
r.t.
r.t.
50 ꢁC
r.t.
1a (88/12)
1b (91/9)
1b (68/32)
1c (94/6)
51
67
71
41
85
89
54
77
4
6
32
6
6
3
3
5
Bu
a
Determined by 1H NMR.
Isolated by distillation.
b

J. Ohshita et al. / Journal of Organometallic Chemistry 691 (2006) 3065–3070
3067
Table 3
Polymer synthesis
CH2
OEt
Si
Mg
H
C
1a-c
C
H
C
THF
reflux
SiR(OEt)
R
x
y
2a-c
Monomer (trans/gem)
Time (h)
Polymer
Yielda (%)
x/yb
Mw (Mw/Mn)c
M.p. (ꢁC)
1a (88/12)
1b (91/9)
120
17
24
24
40
2a
2b
2b
2b
2c
38
66
56
16d
21
92/8
2230 (1.06)
3170 (1.13)
3730 (1.19)
5470 (1.35)
5580 (1.16)
52–56
57–64
63–71
93–105
Oil
87/13
88/12
82/18
89/11
1c (94/6)
a
After reprecipitation from chloroform/EtOH.
Determined by 1H NMR.
Determined by GPC, relative to polystyrene standards.
Purified by reprecipitation from chloroform/pentane.
b
c
d
Table 4
Reactions of 2b
OEt
R
RM
2b
Ar Si
Ph
Ar Si
Ph
THF
a
b
CH2
H
C
C
H
or
Ar =
C
RM
2b Mw (Mw/Mn)c
Time (h)
Product
Yield (%)a
a/bb
Mw (Mw/Mn)c
M.p. (ꢁC)
n-BuLi
CH2@CHMgCl
5470 (1.35)
3700 (1.18)
16
16
40
24
3b
4b
4b
5b
31
23
61
39
2.4/7.6
7.6/2.4
0.5/9.5
7.7/2.3
5730 (1.33)
3070 (1.04)
3540 (1.16)
4400 (1.26)
92–102
61–65
54–60
C
CLi
3730 (1.19)
141–147
a
b
c
After reprecipitation from chloroform/EtOH.
Determined by 1H NMR.
Determined by GPC, relative to polystyrene standards.
0.2
0.15
0.1
the respective substituted polymers 3b and 4b, although
complete substitution could not be performed and par-
tially substituted products were always obtained. The
reaction of pyrenylethnyllithium gave polymer 5b with
only 23% of the silylene units substituted by the pyren-
ylethynyl units.
2b
5b
0.05
2.3. Optical properties of polymers 2b and 5b
0
250
300
350
400
wavelength / nm
Fig. 1 shows the UV absorption spectra of polymers 2b
and 5b in THF. As can be seen in Fig. 1, the spectrum of
polymer 5b shows a broad absorption band due to the
pyrenylethynyl unit at 347 nm. In addition to this, an
absorption due to the phenylenevinylene unit appears at
278 nm in this spectrum, which is almost at the same wave-
length as that of polymer 2b (kmax = 274 nm), indicating
that no significant interaction takes place between these
chromophors with respect to the absorption spectra. In
contrast, as shown in Fig. 2, the emission spectra of poly-
Fig. 1. UV absorption spectra of polymers 2b and 5b in THF.
mer 5b show a broad band, which would arise mainly from
the emission form the pyrenylethynyl unit. Although a
broad shoulder around at 360 nm in these spectra seems
to be ascribed to the phenylenevinylene emission, no evi-
dent peaks from the phenylenevinylene unit are observed,
even when the phenylenevinylene unit is excited at

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J. Ohshita et al. / Journal of Organometallic Chemistry 691 (2006) 3065–3070
3. Conclusion
20
15
10
5
In conclusion, on the basis of the results described
2b
above, we demonstrated that the formation of ethoxy-
substituted poly(silylenephenylenevinylene)s, followed by
nucleophilic substitution, is a convenient method leading
to a variety of poly(silylenephenylenevinylene)s.
4. Experimental
0
300
350
400
450
500
4.1. General
wavelength / nm
15
10
5
(Bromophenyl)(trimethylsily)acetylene [6], diethoxysil-
anes [10], pyrenylethynyllithium [7] were prepared as
reported in the literature. All reactions were carried out
in an atmosphere of dry nitrogen. Toluene and THF were
dried over sodium and distilled just before use. Emission
quantum efficiencies (U) were determined relative to a
THF solution of 9,10-diphenylanthracene as a standard.
Some NMR signals for the minor gem-isomer and frag-
ment could not be observed, probably due to their low
intensities and/or overlapping with those of the major
trans-isomer and fragment. The ratios of subunits in the
present polymers (x/y and a/b in Tables 3 and 4, respec-
tively) were determined on the basis of integration ratios
in the 1H NMR spectra. Molecular weights of the polymers
were determined by GPC eluting with THF, relative to
polystyrene standards. By using seven polystyrene stan-
dards with different molecular weights, we obtained a sec-
ond-order calibration curve with a correlation coefficient
of 0.99932.
5b
a
b
0
300
350
400
450
500
wavelength / nm
Fig. 2. Emission spectra of polymers 2b (top) and 5b (bottom) excited at
278 nm (a) and 334 nm (b) in THF.
278 nm. Fig. 3 shows an emission spectrum of (trimethylsil-
ylethynyl)pyrene [7]. The spectrum involves two maxima at
386 and 407 nm, corresponding to two broad peaks around
400 nm of polymer 5b. Broadening of the spectra of poly-
mer 5b is probably due to its polymeric structure. These
are indicative of that energy transfer from the phenylene-
vinylene unit in the backbone to the pendant pyrenylethy-
nyl unit occurs in the excited state. Intrachain energy
transfer has been reported for alternate polymers com-
posed of a silylene-p-electron system [9,11]. However, little
is known for chain-to-pendant energy transfer in this type
of the polymers. The emission quantum efficiencies were
determined to be U = 0.31 and 0.15 for THF solutions of
polymers 2b and 5b, respectively.
4.2. Preparation of monomers
A
mixture of (bromophenyl)(trimethylsily)acetylene
(14.2 g, 56.1 mmol), potassium carbonate (30.2 g,
219 mmol), and methanol (500 mL) was stirred at room
temperature for 4 h. The mixture was hydrolyzed and
extracted three times with ether. The extracts were com-
bined and dried over anhydrous magnesium sulfate. Evap-
oration of the solvent gave (bromophenyl)acetylene as
1
yellow solids (8.55 g, 47.2 mmol, 84% yield): H NMR (d
in CDCl3) 7.44 (d, J = 8.4 Hz, 2H, Ph), 7.32 (d, J =
8.4 Hz, 2H, Ph), 3.10 (s, 1H, –C„CH); 13C NMR (d in
CDCl3) 133.51 (Ph CH), 131.57 (ipso Ph), 123.11, 120.99
(Ph CH), 82.55 (–C„CH), 78.25 (–C„CH); GC/MS m/z
180 (M+).
8000
7000
6000
5000
4000
3000
2000
1000
0
A
mixture
of
bromophenylacetylene
(2.40 g,
13.3 mmol), diethoxyhexylsilane (2.63 g, 12.9 mmol),
RhCl(PPh3)3 (0.015 g, 0.016 mmol), and toluene (10 mL)
was stirred at room temperature for 48 h. To this was
added ca. 10 mg of a triazine-based complexing agent (San-
kyo Kasei Co. Ltd.) to remove the catalyst. After filtration,
the solvent was removed and the residue was distilled under
reduced pressure to give monomer 1a (2.53 g, 6.56 mmol,
300
350
400
450
500
550
wavelength/nm
1
51% yield): bp 155 ꢁC (4 · 10À6 mmHg); H NMR (d in
Fig. 3. Emission spectrum of (trimethylsilylethynyl)pyrene excited at
350 nm in THF.
CDCl3) 7.45–7.39 (m, phenylene), 7.34–7.29 (m, pheny-

J. Ohshita et al. / Journal of Organometallic Chemistry 691 (2006) 3065–3070
3069
lene), 7.02 (d, J = 19.1 Hz, CH@CH), 6.23 (d, J = 19.1 Hz,
CH@CH), 6.04 (d, J = 1.9 Hz, C@CH2), 5.84 (d,
J = 1.9 Hz, C@CH2), 3.80 (q, J = 6.8 Hz, trans OCH2),
3.71 (q, J = 6.8 Hz, gem OCH2), 1.40–1.15 (m,
SiCH2(CH2)4 and OCH2CH3), 0.83 (t, J = 6.8 Hz, CH3
of Hex), 0.72 (br t, J = 6.7 Hz, SiCH2); 13C NMR (d in
CDCl3) 140.07 (CH@CH), 138.87 (C@CH2), 133.43,
131.62, 130.12, 128.15, 122.66, 119.26 (phenylene,
CH@CH, and C@CH2), 58.42 (trans OCH2), 58.40 (gem
OCH2), 32.94, 31.47, 22.64, 22.54 (Hex), 19.39 (trans
OCH2CH3), 19.21 (gem OCH2CH3), 14.07, 12.94 (Hex);
GC/MS m/z 384 (M+), 339 (M+–OEt), 307 (M+–Br). Anal.
Calc. for C18H29BrO2Si: C, 56.09; H, 7.58. Found: C,
56.47; H, 7.44%. Adding the complexing agent and filtra-
tion of the precipitates before distillation must not be
skipped. The products, otherwise, underwent thermal
decomposition during distillation.
form/ethanol to give polymer 2a (0.28 g, 38% yield) as col-
orless solids: IR 2972, 2873 (C–H), 1069, 912 (Si–O) cmÀ1
;
1H NMR (d in CDCl3) 7.59–7.40 (m, phenylene), 7.01 (d,
J = 19.0 Hz, CH@CH), 6.24 (d, J = 19.0 Hz, CH@CH),
6.03 (d, J = 2.7 Hz, C@CH2), 5.85 (d, J = 2.7 Hz,
C@CH2), 3.70 (q, J = 6.9 Hz, trans OCH2), 3.47 (q, J =
6.9 Hz, gem OCH2), 1.29–1.14 (m, SiCH2(CH2)4CH3 and
OCH2CH3), 0.85–0.71 (m, SiCH2(CH2)4CH3); 13C NMR
(d in CDCl3) 148.47 (CH@CH), 137.04 (C@CH2), 133.48,
131.60, 128.02, 126.14, 122.06, 119.42 (ring carbons,
CH@CH, and C@CH2), 58.68 (trans OCH2), 58.46 (gem
OCH2), 33.21, 31.51, 23.01, 22.59 (Hex), 18.57
(trans OCH2CH3), 18.31 (gem OCH2CH3), 14.11, 13.80
(Hex).
Polymers 2b and 2c were prepared in a similar fashion to
above. Data for 2b: yellow solids; IR 2978, 2867 (C–H),
1
1070, 911 (Si–O) cmÀ1; H NMR (d in CDCl3) 7.78–7.28
Other monomers were prepared in a similar fashion to
above. Data for 1b: b.p. 175 ꢁC (6 · 10À6 mmHg); 1H
NMR (d in CDCl3) 7.70–7.61 (m, phenylene), 7.44–7.26
(m, Ph and phenylene), 7.04 (d, J = 19.2 Hz, CH@CH),
6.39 (d, J = 19.2 Hz, CH@CH), 6.16 (d, J = 2.6 Hz,
C@CH2), 5.94 (d, J = 2.6 Hz, C@CH2), 3.86 (q, J =
7.0 Hz, trans OCH2), 3.71 (q, J = 7.0 Hz, gem OCH2),
1.26 (t, J = 7.0 Hz, trans OCH2CH3), 1.13 (t, J = 7.0 Hz,
gem OCH2CH3); 13C NMR (d in CDCl3) 147.40
(CH@CH), 136.61 (C@CH2), 134.63, 134.30, 131.64,
130.24, 130.07, 128.27, 127.86, 127.75, 122.59, 121.96 (ring
carbons, CH@CH, and C@CH2), 58.86 (trans OCH2),
58.64 (gem OCH2), 18.35 (trans OCH2CH3), 18.11 (gem
OCH2CH3); GC/MS m/z 376 (M+), 331 (M+–OEt), 299
(M+–Br). Anal. Calc. for C18H21BrO2Si: C, 57.29; H,
5.61. Found: C, 57.27; H, 5.53%. Data for 1c: bp 150 ꢁC
(m, ring protons), 7.08 (d, J = 19.0 Hz, CH@CH), 6.74
(d, J = 19.0 Hz, CH@CH), 6.01 (d, J = 2.8 Hz, C@CH2),
5.80 (d, J = 2.8 Hz, C@CH2), 3.93 (q, J = 6.9 Hz, trans
OCH2), 3.80 (q, J = 6.9 Hz, gem OCH2), 1.33 (t,
J = 7.0 Hz, trans OCH2CH3), 1.20 (t, J = 7.0 Hz, gem
OCH2CH3); 13C NMR (d in CDCl3) 148.70 (CH@CH),
139.04 (C@CH2), 134.98, 134.38, 131.63, 130.18, 128.26,
127.89, 127.81, 126.19, 122.60, 122.06 (ring carbons,
CH@CH, and C@CH2), 58.81 (trans OCH2), 58.57 (gem
OCH2), 18.43 (trans OCH2CH3), 18.08 (gem OCH2CH3);
29Si NMR (d in CDCl3) À 12.01, À13.98. Data for 2c: col-
orless oil; 1H NMR (d in CDCl3) 7.60–7.45 (m, phenylene),
7.05 (d, J = 19.0 Hz, CH@CH), 6.60 (d, J = 19.0 Hz,
CH@CH), 6.09 (d, J = 2.9 Hz, C@CH2), 5.87 (d, J =
2.9 Hz, C@CH2), 3.76 (q, J = 6.9 Hz, trans OCH2), 3.58
(q, J = 6.9 Hz, gem OCH2), 1.37–1.14 (m, SiCH2(CH2)2-
CH3 and OCH2CH3), 1.01–0.76 (m, SiCH2(CH2)2CH3);
13C NMR (d in CDCl3) 145.71 (CH@CH), 139.69
(C@CH2), 134.16, 131.36, 128.41, 126.19, 122.89, 119.78
(ring carbons, CH@CH, and C@CH2), 58.65
(trans OCH2), 58.42 (gem OCH2), 27.41, 26.04 (Bu),
19.43 (trans OCH2CH3), 19.21 (gem OCH2CH3), 13.78,
13.69 (Bu).
1
(4 · 10À6 mmHg); H NMR (d in CDCl3) 7.45–7.42 (m,
phenylene), 7.32–7.29 (m, phenylene), 7.02 (d,
J = 19.0 Hz, CH@CH), 6.24 (d, J = 19.0 Hz, CH@CH),
6.04 (d, J = 2.9 Hz, C@CH2), 5.85 (d, J = 2.9 Hz,
C@CH2), 3.81 (q, J = 7.0 Hz, trans OCH2), 3.70 (t, J =
7.0 Hz, gem OCH2), 1.37–1.19 (m, SiCH2(CH2)2CH3 and
OCH2CH3), 0.87 (t, J = 7.0 Hz, CH3 of Bu), 0.73 (br t,
J = 7.0 Hz, SiCH2); 13C NMR (d in CDCl3) 145.44
(CH@CH), 139.84 (C@CH2), 133.26, 131.09, 128.89,
126.32, 122.98, 120.31 (ring carbons, CH@CH, and
C@CH2), 58.74 (trans OCH2), 58.55 (gem OCH2), 26.75,
26.13 (Bu), 19.79 (trans OCH2CH3), 19.58 (gem
OCH2CH3), 13.81, 13.75 (Bu); GC/MS m/z 356 (M+),
331 (M+ÀOEt), 299 (M+ÀBu). Anal. Calc. for
C16H25BrO2Si: C, 53.78; H, 7.05. Found: C, 53.72; H,
7.05%.
4.4. Reactions of polymer 2b
To a solution of polymer 2b (5.6 mg, 0.22 unit mol) in
THF (5 mL) was added a 1.60 M of butyllithium in hexane
(0.14 mL, 0.22 mmol) at À40 ꢁC. The mixture was stirred
for 16 h at room temperature. After hydrolysis, the organic
layer was separated and dried over anhydrous magnesium
sulfate. The solvent was evaporated and the residue was
reprecipitated from chloroform/ethanol to give polymer
3b (0.018 g, 31% yield) as colorless solids: IR 2963, 2855
4.3. Synthesis of ethoxy-substituted polymers
(C–H), 1067, 914 (Si–O) cmÀ1 1H NMR (d in CDCl3)
;
A mixture of 1a (1.10 g, 2.85 mmol), magnesium powder
(0.11 g, 4.60 mmol), and THF (15 mL) was heated to reflux
for 120 h. The resulting magnesium salts and excess magne-
sium were removed by filtration. After the solvent was
evaporated, the residue was reprecipitated from chloro-
7.53–7.34 (m, phenylene), 6.95 (d, J = 19.2 Hz, CH@CH),
6.76 (d, J = 19.1 Hz, CH@CH), 6.22 (d, J = 2.8 Hz,
C@CH2), 5.92 (d, J = 2.8 Hz, C@CH2), 3.70 (q,
J = 6.9 Hz, trans OCH2), 3.54–3.48 (m, gem OCH2),
1.39–1.18 (m, SiCH2CH2CH2CH3 and OCH2CH3),

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J. Ohshita et al. / Journal of Organometallic Chemistry 691 (2006) 3065–3070
0.94–0.84 (m, SiCH2CH2CH2CH3); 13C NMR (d in CDCl3)
148.37 (CH@CH), 138.24 (C@CH2), 135.57, 135.24,
134.55, 134.26, 129.33, 127.85, 127.71, 127.78, 126.00,
121.79 (ring carbons, CH@CH, and C@CH2), 58.84
(trans OCH2), 58.56 (gem OCH2), 26.66, 26.06 (Bu),
18.61 (trans OCH2CH3), 18.45 (gem OCH2CH3), 13.74,
13.70 (Bu).
Acknowledgements
This work was supported by a Grant-in Aid for Scientific
Research (No. 17550105) from the Ministry of Education,
Science, Sports, and Culture of Japan and NEDO (Project
No. 04A25015). We thank Sankyo Kasei Co. Ltd., Tokuy-
ama Co. Ltd., and Tokuyama Science Foundation for finan-
cial support. We thank Sankyo Kasei Co. Ltd. also for the
gift of the complexing agent that was used to remove the
Rh-catalyst from the reaction mixtures of hydrosilation.
Other substitution reactions were carried out as above.
Data for 4b: colorless solids; IR 2979, 2864 (C–H), 1106,
1
960 (Si–O) cmÀ1; H NMR (d in CDCl3) 7.65–7.31 (m,
phenylene), 7.11 (d, J = 18.8 Hz, CH@CH), 6.82 (d,
J = 18.8 Hz, CH@CH), 6.28–6.22 (m, vinyl), 6.05–6.02
(m, C@CH2), 5.94–5.87 (m, vinyl), 5.83–5.80 (m,
C@CH2), 3.87 (q, J = 6.9 Hz, trans OCH2), 3.71–3.67
(m, gem OCH2), 1.25 (t, J = 6.9 Hz, trans OCH2CH3),
1.17–1.12 (m, gem OCH2CH3); 13C NMR (d in CDCl3)
148.81 (CH@CH), 139.12 (C@CH2), 135.35, 135.00,
134.67, 134.43, 131.68, 130.05, 128.55, 128.30, 127.92,
126.81, 126.24, 123.49 (ring carbons, CH@CH, C@CH2,
and SiCH@CH2), 59.65 (trans OCH2), 59.45 (gem
OCH2), 18.45 (trans OCH2CH3), 18.21 (gem OCH2CH3).
Data for 5b: blue purple solids; IR 2972, 2871 (C–H),
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