J. Wang et al.
Polymer 187 (2020) 122081
Fig. 4. FTIR spectra of 4 and partly crosslinked poly(4) (For the codes see Chart 1 and Schemes 2 and 3).
–
-
C
–
CH).
(br, 0.1H, SiH), 4.21 (br, 2.0H, SiH), 0.40–0.22 (br, 0.6H, Si(CH
.22–0.03 (br, 12H, Si(CH ). Polymerization of 3 was carried out
similarly.
3 2
) ),
0
3 2
)
2
.2.2.3. 3,5-Bis(dimethylsilyl)phenylacetylene(3). To a THF solution (34
mL) of 5a (880 mg, 3.40 mmol), 1.57 mol/L of n-butyllithium hexane
�
solution (6.40 mL, 10.0 mmol) was added dropwised at À 75 C. The
2.3.2. Synthesis of linear soluble poly(2) from poly(1)(Scheme 3(C))
To a toluene (2.5 mL) and CH CN (0.5 mL) solution of poly(1) (88.0
mg, 0.550 mmol, 1.0 equiv) and water (200 l, 11.0 mmol, 20 equiv)
under air, the (RuCl (p-cymene)) (7.40 mg, 10.0 mol) was added into
�
solution was stirred at À 75 C for 4 h and a THF solution (5 mL) of
3
chlorodimethylsilane (750
μ
L, 6.70 mmol) was added dropwise. The
μ
temperature of the reaction solution was enhanced to slowly and kept
overnight. The stirring was continued for another 1 h after an excess of
water was added to the solution. This reaction solution was extracted
with diethyl ether, washed with brine, and dried over anhydrous sodium
sulfate for 1 h. After filtration and concentration, the crude product was
purified by silica-gel column chromatography to give 3 as a colorless
2
2
μ
the reaction system. The solution was stirred at room temperature for 2
h. The crude polymer was purified by reprecipitation of the polymer
solution into a large amount of methanol and the formed solid was dried
in vacuo for 24 h to give linear poly(2) as a brown solid.
liquid. Yield: 41.0% (300 mg). R
f
¼ 0.4 (ethyl acetate/hexane ¼ 1/20
2.3.3. Preparation of membranes of linear soluble poly(1), poly(2), poly
(3) and poly(5)
1
(
v/v)). H NMR (CDCl , 400 MHz, ppm): δ 7.67 (s, 3H, ArH), 4.43 (hept,
3
–
2
H, -Si(CH
3
)
2
H), 3.10 (s, 1H, -C
–
CH), 0.35 (d, 12H, -Si(CH
3
)
2
) (Fig. 2).
A toluene solution(1.0 mL) of the linear poly(1) (50.0 mg) was casted
on a poly(tetrafluoroethylene) sheet. After the solvent was evaporated
for 24 h at room temperature, the membrane was detached from the poly
2
.2.2.4. 3,5-Bis(hydroxydimethylsilyl)phenylacetylene(4). To a CH
mol, 1.0 equiv) and water (400
2.0 mmol, 40 equiv) under air, the (RuCl (p-cymene)) (14.8 mg, 20.0
3
CN
(
tetrafluoroethylene) sheet and dried in vacuo for 24 h at room tem-
(
3.0 mL) solution of 3 (120 mg, 550
μ
μl,
perature. Preparation of poly(3) and poly(5) membranes were carried
out similarly. Although we tried to prepare poly(2) membranes, no
membrane was obtained.
2
2
2
μ
mol) was added into the solution. The solution was stirred at room
temperature for 15 min and the reaction was seen to be complete by
TLC. The reaction was diluted with hexane (5 mL) and the crude product
was purified by alumina column chromatography to give 4 as a colorless
2
.4. Synthesis and in-situ membrane preparation of partly cross-linked
1
liquid. Yield: 20.1% (27.0 mg). R
NMR (CDCl
8.0 Hz, 2H, ArH), 3.09 (s, 1H, -C
2H, -Si(CH )(Fig. 2). Anal. Calcd. for C12H18O2Si2: C, 57.55; H,
.24; O, 12.78; Found: C, 57.50; H, 7.29; O, 12.72. IR (KBr): 3410(O–H),
f
¼ 0.45 (hexane/ether ¼ 7/3(v/v)). H
insoluble polymers
3
, 400 MHz, ppm): δ 7.92 (t, J ¼ 8.0 Hz, 1H, ArH), 7.61 (d, J
–
CH), 1.55 (s, 2H, -SiOH), 0.33 (d,
¼
–
Although usually an achiral amine is used for the polymerization, we
used the chiral amine(PEA) for the polymerization of 1 and 3 to avoid
simultaneous silylation by the Rh cat [5]. Therefore, in this study, we
also selected the same condition with that for 2 and 4.
1
7
3
3 2
)
–
À 1
302 (HC C), 1251 (SiC) cm (Fig. 4).
–
2
2
.3. Synthesis of linear soluble polymers
2.4.1. Synthesis and in-situ membrane preparation of partly cross-linked
insoluble polymers from one SiOH-containing monomer (2)
.3.1. Polymerization of SiH-containing monomers (1 and 3)
A solution of [RhCl(nbd)]
was added to a toluene solution (1.0 mL) of 1 (84.0 mg, 200
phenylethylamine (PEA) (48.4 mg, 400 mol) to avoid simultaneous
2
(370
μ
g, 8.00
μ
mol) in toluene (1.0 mL)
2.4.1.1. Polymerization of one SiOH-containing monomer (2). A solution
μmol) and
of [RhCl(nbd)]
(48.0 mg, 400
(1.0 mL) of 2 (32.0 mg, 200
2
(92.5
mol) in toluene (1.0 mL) was added to a toluene solution
mol). The reaction solution was stirred at
μ
g, 2.00
μ
mol) and phenylethylamine (PEA)
μ
μ
hydrosilation by the Rh catalyst [5]. The reaction solution was stirred at
room temperature for 12 h. The crude polymer was purified by repre-
cipitation of the toluene solution into a large amount of methanol and
the formed solid was dried in vacuo for 24 h to give poly(1) as a yellow
μ
room temperature for 4 h and 0.5 mL methanol was added to quench the
polymerization. After the polymerization, the polymerization solution
was homogeneous and no precipitate formed. It was viscos solution.
When we carried out precipitation of the solution into methanol, only
insoluble solids were formed. Therefore, no purification was carried out.
5
1
solid. Yield: 87.0%. Mw ¼ 1.29 ꢀ 10 . H NMR (CDCl
3
, 400 MHz, ppm):
δ 8.0–5.5 (several broad peaks for aromatic and olefinic protons), 4.41
4