Synthesis of Poly(silyl ethers) via Iridium-Catalyzed Dehydrocoupling Polymerization

Article abstract of DOI:10.1021/acs.organomet.8b00316

Poly(silyl ethers) (PSEs) are promising degradable materials, and the development of an efficient method to produce them from readily available materials is highly desirable. Herein, we present a dehydrocoupling polymerization of AB-type silyl alcohol monomers catalyzed by homogeneous iridium(I) complexes bearing a bisphosphine ligand. A series of PSEs containing aliphatic or aromatic linkers have been synthesized. The PDI of PSEs could be tuned by varying the ligand of iridium/bisphosphine complexes. Moderate to high yields of polymers with number-average molecular weights (M_n) up to 9.27 × 10⁴ were obtained. The PSEs possess good thermal stability and low glass-transition temperature (T_g = -42 to -83 °C).

Full text of DOI:10.1021/acs.organomet.8b00316

Article
Cite This: Organometallics XXXX, XXX, XXX−XXX
Synthesis of Poly(silyl ethers) via Iridium-Catalyzed
Dehydrocoupling Polymerization
Xiao-Yong Zhai,† Shu-Bo Hu,† Lei Shi, and Yong-Gui Zhou*
,‡
†
,†
†State Key Laboratory of Catalysis, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, People’s
Republic of China
‡
University of Chinese Academy of Sciences, Beijing 100049, People’s Republic of China
*
S Supporting Information
ABSTRACT: Poly(silyl ethers) (PSEs) are promising degrad-
able materials, and the development of an efficient method to
produce them from readily available materials is highly
desirable. Herein, we present a dehydrocoupling polymer-
ization of AB-type silyl alcohol monomers catalyzed by homogeneous iridium(I) complexes bearing a bisphosphine ligand. A
series of PSEs containing aliphatic or aromatic linkers have been synthesized. The PDI of PSEs could be tuned by varying the
ligand of iridium/bisphosphine complexes. Moderate to high yields of polymers with number-average molecular weights (M )
n
4
up to 9.27 × 10 were obtained. The PSEs possess good thermal stability and low glass-transition temperature (T = −42 to
g
−
83 °C).
4
d,12,13
12a
13,14
INTRODUCTION
on palladium,
platinum,
rhodium,
and manga-
■
1
5
nese have been developed. Generally, the PSEs synthesized
via metal-catalyzed cross-dehydrocoupling polymerization
possess relatively lower M values in comparison to PSEs
synthesized via ring-opening polymerization. Furthermore,
Polymers containing silicon−oxygen bonds in the main chain,
including polysiloxanes, poly(silyl ethers) (PSEs), poly(silyl
esters), etc., possess analogous and intriguing properties: for
n
16
instance, low T , good thermal stability, biocompatibility, and
g
1
,2
boranes could also be used as effective metal-free catalysts in
high gas permeability. These polymers have been applied in
1
7
3
a−c
dehydrocoupling polymerization. Very recently, inorganic
base cesium hydroxide catalyzed dehydrocoupling polymer-
ization of a novel AB-type monomer was also reported by the
Hartwig group. The degree of polymerization can be
controlled by adding various amounts of the AA-type
monomer 1,10-decanediol. Despite these advances, the further
development of efficient strategies for the synthesis of high-
molecular-weight PSEs containing various backbones is still
meaningful.
In transition-metal-catalyzed reactions, the ligand is of great
importance in adjusting reactivity, chemoselectivity, regiose-
lectivity, and enantioselectivity. Recently, we have inves-
tigated the performance of iridium/bisphosphine complexes in
many fields, such as high-temperature elastomers,
con-
3d
ductive polymeric materials, and chiral column packing
3
e
materials. As the result of main-chain hydrolytically
degradable Si−O−C linkages, PSEs are promising degradable
materials. More importantly, the degradability, thermal
stability, and thermomechanical properties of PSEs can be
conveniently adjusted by changing the structure of the
1
8
4
monomers.
Polycondensation of dichlorosilanes and diols is the most
often used method to synthesize PSEs. However, dichlor-
osilanes are moisture-sensitive, which limits their further use.
When dichlorosilanes were replaced with diphenoxy- and
5
19
dianilinosilanes, polymers with high M were obtained at high
n
20
4
a,b,6
asymmetric hydrogenation. In 2010, we found that an
iridium/bisphosphine complex could effectively catalyze
asymmetric hydrogenation of quinolines with triethylsilane
reaction temperature.
Recently, acid-catalyzed silicon
acetal metathesis polymerization (SAMP) further enriched
the methodology of production of PSEs. However, HCl or
7
2
1
and water as the hydrogen source, and a detailed mechanistic
study indicated that the iridium complex could catalyze
dehydrocoupling of triethylsilane and water to form
hexaethyldisiloxane and hydrogen gas. We envisioned that
the above iridium catalyst might be applied in synthesis of
PSEs via the dehydrocoupling polymerization of silyl alcohol
monomers. Iridium catalysts with different ligands should tune
other unwanted byproducts are not avoidable in polyconden-
sation. To overcome this issue, polyaddition of dichlorosilanes
with bis(epoxides) and bis(oxetanes) was developed, providing
PSEs with good regioselectivity in the presence of quaternary
8
ammonium under mild conditions. Usually, hydrosilylation
polymerization of dicarbonyl compounds with dihydrosilanes
4c,9
10
11
can be realized by ruthenium-, rhodium-, and zinc-based
the M and PDI values of PSEs. To the best of our knowledge,
catalytic systems. As an effective and highly atom-economical
method to construct Si−O bonds, dehydrocoupling reactions
of silanes and alcohols have been studied as the chain
propagation of polymerization to synthesize PSEs with
hydrogen gas as the only byproduct. Catalytic systems based
n
homogeneous iridium catalysts have not been applied in the
Received: May 16, 2018
©
XXXX American Chemical Society
A
DOI: 10.1021/acs.organomet.8b00316
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
a
synthesis of PSEs via dehydrocoupling polymerization. Herein,
we report the iridium/bisphosphine complex catalyzed
dehydrocoupling polymerization of AB-type monomers
bearing silane and alcohol moieties to give high-molecular-
weight PSEs (Scheme 1).
Table 1. Optimization of Conditions
Scheme 1. Catalytic Dehydrocoupling Polymerization
b
b
c
entry
1
2
3
4
5
6
7
ligand
Mn
PDI
yield (%)
2900
1300
1.23
1.08
5.74
3.70
3.17
2.11
2.05
n.d.
n.d.
92
79
87
d
PPh3
DPPE
DPPP
DPPB
DCPE
DPPF
49100
92700
70200
67000
76400
80
81
a
Reaction conditions unless specified otherwise: 2a (1 mmol),
[
Ir(COD)Cl] (0.5 mol %), ligand (1 mol %), neat, 100 °C, 24 h.
2
b
d
c
Determined by GPC with RI. Isolated yield; n.d. = not detected.
Ligand (2 mol %).
(
entries 3−5). A polymer with narrower PDI could be
obtained by using electron-rich and highly sterically hindered
ligands (DPPF and DCPE) (entries 6 and 7). Through
RESULTS AND DISSCUSSION
Synthesis of Monomers. Monomers 2a−e could be
conveniently synthesized via two steps (Scheme 2). The first
step is hydrosilylation catalyzed by Karstedt’s catalyst, followed
by reduction using lithium aluminum hydride to give the
desirable monomers.
■
condition optimization, the highest M value of 92700 and PDI
n
18
of 2.05 could be obtained by using DPPP and ferrocene-
derived DPPF, respectively (entry 4 and entry 7). In
consideration of the M value of PSE, we chose [Ir(COD)-
n
Cl] /DPPP as the best catalyst.
2
Next, the effects of reaction temperature, solvent, and metal
precursor were conducted. The results are depicted in Table 2.
Scheme 2. Synthesis of Monomers
a
Table 2. Further Optimization of Conditions
b
b
c
entry
T (°C)
solvent
Mn
PDI
yield (%)
1
2
3
4
5
40
60
80
neat
neat
neat
neat
neat
DCE
dioxane
4100
20500
37500
92700
62000
1.30
1.68
2.08
3.70
3.73
47
92
50
79
gel
Optimization of Conditions. 9-(Dimethylsilyl)nonan-1-
ol (2a) was chosen as the model monomer to conduct the
optimization of conditions. The results are depicted in Table 1.
100
120
100
100
100
100
100
100
d
6
When [Ir(COD)Cl] (0.5 mol %) was used as the catalyst, it
d
2
7
was easy to observe that gases bubbled up. After 24 h, the
product was purified by precipitation; the number-average
d
8
d
CH CN
12900
32400
42900
1.73
1.57
3.10
42
47
91
3
9
toluene
toluene
neat
molecular weight (M ) of the polymer was not satisfactory.
e
n
1
1
0
1
Only a low-M product was obtained (M = 2900, PDI = 1.23)
f
n
n
(
entry 1). To improve the molecular weight, the effect of the
a
Reaction conditions unless specified otherwise: 2a (1 mmol),
Ir(COD)Cl]2 (0.5 mol %), DPPP (1 mol %), 100 °C, 24 h.
Determined by GPC with RI. Isolated yield. Solvent used was 3
mL. Toluene used was 1 mL. [Ir(COD)Cl] was replaced with
Ir(COD)OMe]2.
phosphine ligand was investigated. To our disappointment, a
[
polymer with lower M value (1900) was obtained (entry 2) in
b
c
d
n
the presence of PPh . Afterward, the monophosphine PPh was
e
f
3
3
2
replaced with the bisphosphine DPPE. To our delight, a high-
[
molecular-weight polymer with an M value of 49100 was
n
obtained. This suggested that the catalytic performance of the
iridium/bisphosphine complex is superior to that of the
iridium/monophosphine complex (entry 3). However, the PDI
of the polymer was not satisfactory (PDI = 5.74). Thus, a
series of commercially available bisphosphine ligands were
screened. The PDI of the polymer became gradually narrower
on extending the chain length of the bisphosphine ligands
Lowering the temperature resulted in an apparent decrease of
M (entries 1−3). However, when the temperature was raised
n
to 120 °C, a gel with poor solubility in common organic
solvents was obtained (entry 5), which is not the target
product. Then, the solvent effects were examined. Unfortu-
nately, no product was obtained in 1,2-dichloroethane (DCE)
B
DOI: 10.1021/acs.organomet.8b00316
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
a
or dioxane (entries 6 and 7). Although good PDI values were
Table 4. Thermal Analysis of Polymers
obtained in CH CN and toluene, the M and yield were not
3
n
a
a
b
entry
PSE
T5 (°C)
T50 (°C)
Tg (°C)
ideal (entries 8 and 9). In order to achieve high M and narrow
n
1
2
3
4
5
6
3a
3b
3c
3d
3e
3f
422
421
350
375
324
296
471
469
466
467
412
434
−75.6
−83.2
n.o.
n.o.
−42.1
n.o.
PDI, the solvent was reduced to 1.0 mL. However, poor PDI
was observed (entry 10). When [Ir(COD)Cl] was replaced
2
with [Ir(COD)OMe] , no reaction took place (entry 11). This
2
suggested that the coordinated anion of the metal precursor
has a prominent influence on polymerization. Therefore, the
optimal reaction conditions were finally established as
a
[
Ir(COD)Cl] /DPPP/neat/100 °C/24 h.
Temperature at which 5% and 50% mass loss are observed under N
2
b
2
by TGA. Determined by DSC; n.o. = not observed.
Substrate Scope. With the optimal conditions in hand, the
generality of the dehydrocoupling polymerization was
investigated (Table 3). For the monomers containing aliphatic
to suffer pyrolysis (entries 5 and 6). Thus, these PSEs have
thermal stabilities similar to those of PSEs synthesized via
22
hydrosilylation. For polymers 3a,b, low glass transition
temperatures (around −80 °C) could be detected (entries 1
and 2). However, polymers 3c,d,f exhibited an indiscernible
glass transition via DSC (entries 3, 4, and 6). For polymer 3e
Table 3. Substrate Scope: Monomers Containing Aliphatic
a
and Aromatic Backbones
containing an aromatic backbone, the T value was higher than
g
that of polymers containing aliphatic backbones (entry 5). This
indicated that incorporating aromatic groups in the main chain
of the polymer might increase the barrier of longitudinal
23
motion of the polymer chains.
Methanolysis. The degradability of polymer 3e was
examined in a THF/methanol mixture at room temperature
(
Figure 1). The change in the M value of polymer 3e was
n
b
b
c
entry
monomer
Mn
PDI
yield (%)
1
2
3
4
5
2a
2b
2c
2d
2e
2b + 2e
92700
46900
25500
30500
20800
15000
3.70
2.90
2.55
2.39
1.71
1.89
79 (3a)
80 (3b)
98 (3c)
96 (3d)
75 (3e)
78 (3f)
d
6
a
Reaction conditions unless specified otherwise: 2a−e (1 mmol),
Ir(COD)Cl] (0.5 mol %), DPPP (1 mol %), neat, 100 °C, 24 h.
[
2
b
c
d
Determined by GPC with RI. Isolated yield. 2b (0.5 mmol) and 2e
0.5 mmol) were used.
(
backbones, dehydrocoupling polymerization proceeded
smoothly (entries 1−4). The M value of PSE 3b is close to
Figure 1. Degradation behavior of polymers in a THF/methanol
mixture (80/20, v/v) at room temperature.
n
the value reported for cesium hydroxide catalyzed dehydro-
18
coupling polymerization (Mn = 49000 vs 46900). For
monomers containing aromatic backbones (entry 5), the
dehydrocoupling polymerization also proceeded smoothly with
monitored by GPC. As shown in Figure 1, the M
polymer dropped quickly from 21500 to 17700 in 2 h. Then,
the M value of the polymer decreased to 3600 within 242 h
value of the
n
an M value of 20800 and slightly better PDI value of 1.71. In
n
n
order to make this strategy more versatile, the copolymeriza-
tion of monomers 2b and 2e was conducted. To our delight,
via slow degradation.
Plausible Mechanism. On the basis of these results and
24
the desired product was obtained with an M value of 15000
early studies, a plausible mechanism is proposed for the
iridium-catalyzed dehydrocoupling polymerization of an AB-
type monomer (Scheme 3). First, iridium hydride intermediate
A is formed via oxidative addition of the Si−H bond to the
iridium(I) species. Then, intermediate A undergoes direct
nucleophilic attack of another monomer at the coordinated
silicon to furnish the dehydrocoupling product and inter-
mediate B. Finally, reductive elimination of intermediate B
provides hydrogen gas and regenerates iridium(I) species to
complete the catalytic cycle.
n
and PDI value of 1.89 (entry 6). Because monomer 2b can
randomly react with itself or monomer 2e, the ratio of
fragments of monomers 2b and 2e in polymer chain is 1:1.
Thermal Analysis. After purification by precipitation, the
PSEs produced by the Ir-catalyzed dehydrocoupling polymer-
ization were, in general, colorless/faint yellow viscous oils/soft
solids, depending on the molar masses and backbones of
polymers. The thermal properties of these polymers were
investigated under a nitrogen atmosphere using TGA and DSC
(
Table 4). For chainlike polymers, T50 values of 3a−d were
SUMMARY
kept at around 470 °C, which indicated that these polymers all
■
exhibit good thermal stability (entries 1−4). However, the T
In conclusion, we have demonstrated that an iridium/
bisphosphine complex can effectively catalyze dehydrocoupling
polymerization for the synthesis of various PSEs from AB-type
monomers. For the monomers containing aliphatic and
5
values of chainlike polymers were quite different (from 350 to
4
22 °C). Relatively speaking, copolymerization product 3f and
polymer 3e containing an aromatic backbone were more likely
C
DOI: 10.1021/acs.organomet.8b00316
Organometallics XXXX, XXX, XXX−XXX

Organometallics
Article
under reduced pressure. The residue was purified by silica gel column
chromatography (50/1 to 20/1 hexanes/ethyl acetate) and then
distilled to give monomer 2 as a colorless liquid. To impove the
polymerization performance of monomers, an anhydration process
was necessary to reduce the moisture content of monomers. Toluene
Scheme 3. Possible Mechanism for Ir-Catalyzed
Dehydrocoupling Polymerization
(
30 mL) and ethanol (7 mL) were added to monomer 2, the
azeotropic solvent was evaporated by fractional distillation, and the
mixture was distilled under reduced pressure to obtain anhydrous
monomer 2 as a colorless liquid.
9
-(Dimethylsilyl)nonan-1-ol (2a): 90 mmol scale, 4.049 g, 22%
overall yield, colorless liquid, new compound, R = 0.24 (hexanes/
f
1
ethyl acetate = 10/1). H NMR (400 MHz, CDCl ): δ 3.87−3.79 (m,
3
1
1
H), 3.63 (t, J = 6.6 Hz, 2H), 1.62−1.50 (m, 2H), 1.41−1.27 (m,
13
3H), 0.63−0.50 (m, 2H), 0.05 (d, J = 3.7 Hz, 6H). C NMR (100
MHz, CDCl ): δ 63.3, 33.4, 33.0, 29.7, 29.6, 29.5, 25.9, 24.5, 14.3,
3
+
−
2
4.2. HRMS-ESI: calcd for C H OSi [M − H] , 201.1669; found
1
1
25
01.1670.
1
1-(Dimethylsilyl)undecan-1-ol (2b): 31 mmol scale, 2.200 g, 31%
overall yield, colorless liquid, known compound, R = 0.20 (hexanes/
f
1
ethyl acetate = 10/1). H NMR (400 MHz, CDCl ): δ 3.88−3.77 (m,
3
aromatic backbones, dehydrocoupling polymerization could
occur; moderate to high yields of polymers and number-
1H), 3.63 (t, J = 6.6 Hz, 2H), 1.62−1.51 (m, 2H), 1.38−1.25 (m,
1
3
17H), 0.61−0.53 (m, 2H), 0.05 (d, J = 3.7 Hz, 6H). C NMR (100
4
MHz, CDCl ): δ 63.3, 33.4, 33.0, 29.8, 29.8, 29.63, 29.6, 25.9, 24.6,
average molecular weights of up to 9.27 × 10 were obtained.
3
1
4.4, −4.2.
The PSEs possess good thermal stability and low glass-
1
0-(Dimethylsilyl)decan-1-ol (2c): 72 mmol scale, 2.388 g, 15%
transition temperature (T = −42 to −83 °C). Further work
g
overall yield, colorless liquid, new compound, R = 0.34 (hexanes/
f
will focus on improving the PDI of polymers and synthesis of
optically active PSEs.
1
ethyl acetate = 10/1). H NMR (400 MHz, CDCl ): δ 3.87−3.78 (m,
3
1
1
H), 3.63 (t, J = 6.6 Hz, 2H), 1.61−1.50 (m, 2H), 1.38−1.26 (m,
13
5H), 0.64−0.49 (m, 2H), 0.05 (d, J = 3.7 Hz, 6H). C NMR (100
): δ 63.3, 33.4, 33.0, 29.8, 29.7, 29.6, 29.5, 25.9, 24.6,
EXPERIMENTAL SECTION
■
MHz, CDCl
3
+
General Considerations. All reactions were carried out under an
atmosphere of nitrogen using standard Schlenk techniques, unless
otherwise noted. Commercially available reagents were used without
further purification. Solvents were treated prior to use according to
14.4, −4.2. HRMS-ESI: calcd for C12H27OSi [M − H] , 215.1826;
found, 215.1825.
7-(Dimethylsilyl)heptan-1-ol (2d): 142 mmol scale, 3.516 g, 14%
overall yield, colorless liquid, new compound, R = 0.27 (hexanes/
f
1
13
1
the standard methods. H NMR and C NMR spectra were recorded
at room temperature in CDCl3 on 400 MHz instrument with
tetramethylsilane (TMS) as internal standard. Flash column
chromatography was performed on silica gel (200−300 mesh).
GPC was performed on a Waters 1515 chromatography system
equipped with an Agilent PL1110 column using THF as the eluent
ethyl acetate = 10/1). H NMR (400 MHz, CDCl ): δ 3.87−3.78 (m,
3
1H), 3.63 (t, J = 6.6 Hz, 2H), 1.62−1.50 (m, 2H), 1.37−1.30 (m,
1
3
9H), 0.64−0.52 (m, 2H), 0.05 (d, J = 3.7 Hz, 6H). C NMR (100
MHz, CDCl ): δ 63.3, 33.3, 33.0, 29.3, 25.9, 24.5, 14.3, −4.2. HRMS-
3
+
ESI: calcd for C H OSi [M − H] , 173.1356; found, 173.1359.
9
21
(4-(3-(Dimethylsilyl)propoxy)phenyl)methanol (2e): 95 mmol
(
35 °C, 1 mL/min). Polystyrene standards were used for calibration.
scale, 5.770 g, 27% overall yield, colorless liquid, new compound, R
f
1
DSC was performed on a DSC Instruments 204 HP calorimeter
= 0.19 (hexanes/ethyl acetate = 10/1). H NMR (400 MHz, CDCl ):
3
(
purge gas, N ; flow rate, 20 mL/min; ramp rate, 10 °C/min;
δ 7.27 (d, J = 8.6 Hz, 2H), 6.88 (d, J = 8.6 Hz, 2H), 4.60 (s, 2H),
3.87−3.95 (m, 3H), 1.89−1.77 (m, 2H), 1.67−1.60 (br, 1H), 0.76−
2
temperature range, −100 to +300 °C). TGA was performed on a STA
Instruments 449 F3 thermogravimetric analyzer under nitrogen from
1
3
0.66 (m, 2H), 0.11 (d, J = 3.7 Hz, 6H). C NMR (100 MHz,
2
5 to 600 °C at a ramp rate of 10 °C/min.
CDCl ): δ 158.9, 133.1, 128.8, 114.8, 70.5, 65.3, 24.4, 10.5, −4.3.
3
+
Preparation of Monomers. Monomers 2a−e were conveniently
HRMS-ESI: calcd for C H O Si [M − H] , 223.1149; found,
1
2
19
2
18
prepared according to the literature method. Monomer 2b is a
known compound, and its NMR data matched the literature data.
223.1147.
18
General Procedure for the Polymerization. In an oven-dried
5 mL resealable Schlenk flask equipped with a magnetic stir bar were
2
charged DPPP (4.2 mg, 0.01 mmol), [Ir(COD)Cl] (3.4 mg, 0.005
2
mmol), and DCM (3 mL) under nitrogen. The solution was stirred at
room temperature for 10 min. Then the solvent was removed under
reduced pressure to prepare the catalyst in situ. Monomer 2 (1 mmol)
was placed in the flask under nitrogen. The flask was heated at 100 °C
To a mixture of chlorodimethylsilane (7.896 g, 86 mmol) and 1
72 mmol) in a 125 mL sealed tube was added Karstedt’s catalyst
∼2% xylene solution, 7 μL, 0.001 mol %). The tube was heated
(
(
for 24 h under nitrogen (connected to an N
the last 6 h of the reaction time, H produced during the reaction was
replaced with N every 2 h. After the polymerization, the reaction
2
Schlenk line). During
2
under nitrogen at 50 °C for 12 h. After the tube was cooled to room
2
temperature, the contents of the flask were added dropwise to a
mixture was cooled to room temperature, and the contents was
purified by a precipitation method.
stirred suspension of LiAlH (4.819 g, 129 mmol) in dry THF (350
4
mL) in an oven-dried 1 L flask under nitrogen at 0 °C. The flask was
shaken by hand occasionally to break up the chunks that formed.
After the addition of the chlorosilane intermediate, the flask was
heated at 55 °C for 2 h before it was cooled to 0 °C. The reaction
mixture was quenched by slow addition of ethyl acetate (80 mL). To
the mixture was added dropwise an aqueous solution of Rochelle salt
All of the polymers are soluble in tetrahydrofuran and insoluble in
methanol. Therefore, these two solvents were used in the
precipitation process. The reaction mixture was first homogenized
by the addition of an as low as possible amount of THF (1−2 mL),
and then cold methanol was added portionwise (15−20 mL) until a
change occurred to a biphasic mixture. The top layer was taken out,
and the bottom viscous/solid layer was washed with MeOH two times
until it gave a white/light yellow color viscous/solid polymer. The
resulting polymer was dried to a constant weight and characterized by
(
40 g in 150 mL of water). The mixture was stirred vigorously. Then
the aqueous layer was extracted with hexanes (100 mL × 2). The
combined organic layers were washed with water (100 mL × 2) and
brine (100 mL), dried over sodium sulfate, filtered, and concentrated
1
13
H NMR, C NMR, GPC, TG, and DSC.
D
DOI: 10.1021/acs.organomet.8b00316
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Organometallics
Article
1
Polymer 3a: colorless soft solid (0.158 g, 79% yield). H NMR
REFERENCES
■
(
1
(
1
400 MHz, CDCl ): δ 3.56 (t, J = 6.7 Hz, 2H), 1.57−1.45 (m, 2H),
3
1
3
(1) Kawakami, Y.; Li, Y. Approaches to polymers containing a
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3
3
99−419.
6.6, −1.9.
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1
(2) Moretto, H.-H.; Schulze, M.; Wagner, G. Silicones. In Ullmann’s
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(
1
(
2
3
1
3
.34−1.24 (m, 16H), 0.64−0.49 (m, 2H), 0.08 (s, 6H). C NMR
(
3) (a) Shea, K. J.; Loy, D. A.; Webster, O. Arylsilsesquioxane gels
100 MHz, CDCl ): δ 63.0, 33.7, 33.0, 29.9, 29.8, 29.7, 29.6, 26.1,
3
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3.4, 16.6, −1.9.
Polymer 3c: colorless soft solid (0.210 g, 98% yield). H NMR
400 MHz, CDCl ): δ 3.56 (t, J = 6.7 Hz, 2H), 1.58−1.45 (m, 2H),
1
(
1
(
2
3
1
3
.34−1.23 (m, 14H), 0.65−0.49 (m, 2H), 0.08 (s, 6H). C NMR
100 MHz, CDCl ): δ 63.0, 33.7, 33.0, 29.9, 29.8, 29.7, 29.6, 26.1,
3
3
4. (c) Lauter, U.; Kantor, S. W.; Schmidt-Rohr, K.; MacKnight, W. J.
3.4, 16.6, −1.9.
Polymer 3d: colorless viscous oil (0.166 g, 96% yield). H NMR
400 MHz, CDCl ): δ 3.55 (t, J = 6.7 Hz, 2H), 1.56−1.44 (m, 2H),
1
Vinyl-substituted silphenylene siloxane copolymers: Novel high-
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1
3
1
3
.34−1.26 (m, 8H), 0.62−0.51 (m, 2H), 0.07 (s, 6H). C NMR (100
MHz, CDCl ): δ 63.0, 33.7, 33.0, 29.4, 26.0, 23.4, 16.5, −1.9.
3
1
Polymer 3e: light yellow solid (0.166 g, 75% yield). H NMR (400
6
59−663. (e) Yi, G.; Bradshaw, J. S.; Rossiter, B. E.; Reese, S. L.;
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3
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4
.64 (s, 2H), 3.90 (t, J = 6.7 Hz, 2H), 1.91−1.76 (m, 2H), 0.81−0.66
13
(
m, 2H), 0.16 (s, 6H). C NMR (100 MHz, CDCl ): δ 158.5, 133.0,
3
1
28.2, 114.5, 70.6, 64.7, 23.4, 12.6, −1.8.
Polymer 3f: light yellow oil (0.175 g, 78% yield). H NMR (400
MHz, CDCl ): δ 7.26−7.19 (m, 2H), 6.90−6.81 (m, 2H), 4.62 (d, J =
1
3
7
.3 Hz, 2H), 3.90 (dd, J = 12.4, 6.4 Hz, 2H), 3.57 (dd, J = 14.7, 6.9
Hz, 2H), 1.88−1.78 (m, 2H), 1.56−1.46 (m, 2H), 1.36−1.24 (m,
1
6H), 0.80−0.64 (m, 2H), 0.64−0.54 (m, 2H), 0.20−0.05 (m, 12H).
1
3
C NMR (100 MHz, CDCl ): δ 158.5, 133.2, 133.0, 129.6, 128.8,
3
1
2
−
28.2, 114.8, 114.5, 71.7, 70.6, 64.7, 64.6, 63.1, 63.0, 33.7, 33.0, 29.8,
9.7, 29.6, 26.0, 23.4, 18.6, 16.6, 14.5, 12.7, 12.6, 0.5, −0.1, −1.8,
5
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(
was taken for GPC analysis after stirring for a certain time.
ASSOCIATED CONTENT
■
*
S
Supporting Information
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(
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AUTHOR INFORMATION
■
Corresponding Author
(
tetramethyldisilylene)]s via melt copolymerization reaction. Bull.
Korean Chem. Soc. 2013, 34, 1637−1642.
6) (a) Padmanaban, M.; Kakimoto, M.; Imai, Y. Synthesis and
*
E-mail for Y.-G.Z.: ygzhou@dicp.ac.cn.
(
ORCID
characterization of new photosensitive poly (oxyaryleneoxydisilane)s
from 1, 2-bis (diethylamino) tetramethyldisilane and various bi-
sphenols. J. Polym. Sci., Part A: Polym. Chem. 1990, 28, 2997−3005.
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Xiao-Yong Zhai: 0000-0002-4438-6940
Shu-Bo Hu: 0000-0002-8068-7070
Yong-Gui Zhou: 0000-0002-3321-5521
Notes
(7) Sahmetlioglu, E.; Nguyen, H. T. H.; Nsengiyumva, O.; Gokturk,
The authors declare no competing financial interest.
E.; Miller, S. A. Silicon acetal metathesis polymerization. ACS Macro
Lett. 2016, 5, 466−470.
ACKNOWLEDGMENTS
(8) (a) Nishikubo, T.; Kameyama, A.; Kimura, Y.; Fukuyo, K. Novel
synthesis of poly(silyl ethers) by the addition reaction of bis-
■
Financial support from the National Natural Science
Foundation of China (21532006, 21690074), the Dalian
Bureau of Science and Technology (2016RD07), and the
strategic priority program of the Chinese Academy of Sciences
(
epoxides) with dichlorosilanes or bis(chlorosilanes). Macromolecules
995, 28, 4361−4365. (b) Nishikubo, T.; Kameyama, A.; Hayashi, N.
1
A novel synthesis of poly(silyl ether)s by addition reactions of
diepoxide with dichlorosilane compounds. Polym. J. 1993, 25, 1003−
1005. (c) Minegishi, S.; Ito, M.; Nishikubo, T.; Kameyama, A.
(
XDB17020300) is acknowledged.
E
DOI: 10.1021/acs.organomet.8b00316
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