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was continued for 1 h at room temperature, and then the reac-
tion mixture was heated at 50 8C for 3 h. The resulting crude
product was purified by vacuum distillation (100 8C, 0.2
mmHg) to give the product 5 as a colorless oil in 39% yield
(11.00 g).
catalyst (2.1–2.4% Pt in xylene, 5 lL) to the reaction mix-
ture, the reaction was heated at 120 8C for 2 h. After cooling
to room temperature, the reaction mixture was diluted with
CHCl3 and filtered through activated charcoal/Celite. Volatile
substances in the polymer solution were removed using a
rotary evaporator. The polymer was obtained as a colorless
viscous oil in 94% yield (1.52 g): Poly(2,2,9,9-tetramethyl-
2,9-disila-1-oxanona-nylene)15 (9)
1H NMR (400 MHz, C6D6, d): 4.72 (s, 1H; Si-H), 3.93 (t,
J 5 5.2 Hz, 6H; OCH2), 3.32 (t, J 5 5.2 Hz, 6H; OCH2), 3.11 (s,
9H; OCH3); 13C NMR (100 MHz, C6D6, d): 73.3, 61.9, 58.1;
Anal. calcd. for C9H22O6Si: C 42.50, H 8.72, O 37.74, Si 11.04;
found: C 42.48, H 8.68.
1H NMR (400 MHz, CDCl3, d): 1.30 (s, 8H; CH2), 0.51 (br, 4H;
SiCH2), 0.04 (s, 12H; SiCH3); 13C NMR (100 MHz, CDCl3, d):
33.2, 23.2, 18.5, 0.4; Mw 5 3230 gmol21, Mn 5 2560 gmol21
Mw/Mn 5 1.26 by GPC.
,
Synthesis of 2,10-Dimethyl-3,6,9-Trioxa-2,10-
Disilaundecane (6)
Dichloromethane (200 mL), diethylene glycol (4.00 g, 37.7
mmol), triethylamine (21 mL, 150.8 mmol), and a stir bar were
placed in a 500 mL three-necked flask equipped with a dropping
funnel, condenser, and fritted tube. The flask was then cooled
with an ice bath. Nitrogen was introduced through the fritted
tube, and chlorodimethylsilane (8.20 g, 86.7 mmol) was added
dropwise to the reaction mixture from the dropping funnel and
stirred for 24 h at room temperature. The resulting crude product
was purified by vacuum distillation (80 8C, 0.2 mmHg) to give the
product 6 as a colorless oil in 76% yield (6.38 g):
Copolymerization of 2,10-Dimethyl-3,6,9-Trioxa-2,10-
Disilaundecane (6) with 1,5-Hexadiene by Karstedt
Catalyst
A 25 mL Schlenk flask equipped with a magnetic stir bar was
flushed with nitrogen. A solution of 1,5-hexadiene (0.61 g, 7.4
mmol) and 6 (1.64 g, 7.4 mmol) was placed in the flask. After
adding Karstedt catalyst (2.1–2.4% Pt in xylene, 5 lL) to the
flask, the mixture was heated at 120 8C for 2 h. After cooling to
room temperature, the reaction mixture was diluted with CHCl3
and filtered through activated charcoal/Celite. Volatile substan-
ces in the polymer solution were removed using a rotary evapo-
rator. The polymer was obtained as a colorless viscous oil in
98% yield. (2.23 g): Poly(1,1,9,9-tetramethyl-2,5,8-trioxa-1,9-
disilapentadecane) (10)
1H NMR (400 MHz, CDCl3, d): 4.63 (s, 2H; Si-H), 3.78 (m, 4H;
OCH2), 3.58 (m, 4H; OCH2), 0.21 (s, 12H; SiCH3); 13C NMR (100
MHz, CDCl3, d): 72.5, 63.5, 21.4; Anal. calcd. for C8H22O3Si2:
C 43.20, H 9.97, O 21.58, Si 25.25; found: C 43.21, H 9.86.
1H NMR (400 MHz, CDCl3, d): 3.70 (m, 4H; OCH2), 3.53 (m,
4H; OCH2), 1.28 (br, 8H; CH2), 0.57 (br, 4H; SiCH2), 0.07 (s,
12H; SiCH3); 13C NMR (100 MHz, CDCl3, d): 72.6, 62.0, 36.2,
33.2, 30.2 23.1, 18.4, 16.3, 15.4, 0.37, 22.1; Mw 5 17,700
gmol21, Mn 5 9260 gmol21, Mw/Mn 5 1.91 by GPC.
General Procedure A for Hydrosilylation of MeO-PEG-
OAllyl Derivatives (1a-c) by Karstedt Catalyst
A 100 mL Schlenk flask equipped with a magnetic stir bar
was charged with 1a, 1b, or 1c (0.2–0.5 mmol). The system
was vacuum dried at 70 8C and backfilled with nitrogen (3
cycles). Karstedt catalyst (2.1–2.4% Pt in xylene, 20 lL) and
trialkoxysilane (1.2–3.0 equiv) were sequentially added to
the mixture through the septum with a syringe, and the mix-
ture was stirred at 70 8C for 12 h. The reaction product was
filtered, and the filtrate was dripped into diethyl ether
(100 mL) at 0 8C to precipitate the polymer.
Calculation of Degree of Conversion
1
An example of the H NMR spectrum of the reaction mixture
after hydrosilylation is shown in Supporting Information
Figure S1.16 The degree of conversion (DOC) for the reaction
was estimated by 1H NMR spectroscopic analysis according
to the following eq 1:
General Procedure B for Hydrosilylation of 2, 3,
and 4 by Karstedt Catalyst
Ih=2
DOC ð%Þ5
3100
(1)
IEi1 IZi1 Iun1ðIr=3Þ1ðIh=2Þ
An open screw-capped culture tube was capped with a Teflon-
lined septum and charged with 2, 3, or 4 (0.2–0.5 mmol). The
system was vacuum dried at 70 8C and backfilled with nitrogen
(3 cycles). Karstedt catalyst (2.1–2.4% Pt in xylene, 20 lL), tri-
alkoxysilane (1.2–3.0 equiv), and solvent (diglyme) were
sequentially added to the mixture through the septum with a
syringe, and the mixture was stirred at 70 8C for 12 h. The
reaction was monitored by 1H NMR spectroscopy.
where Ih (h 5 hydrosilylated peak) is the integral peak area of
the signals at 0.6 ppm corresponding to ACH2SiA of the result-
ing products. Likewise, Ir (r 5 reduced peak) is the peak area
of ACH3 (0.9 ppm), Iun (un 5 unreacted peak) is the peak area
of ACH@CH2 (5.3 ppm), IEi (Ei 5 E-isomer peak) is the peak
area of AOCH@CHA (6.2 ppm), and IZi (Zi 5 Z-isomer peak) is
the peak area of AOCH@CHA (6.0 ppm).
Copolymerization of 1,1,3,3-Tetramethyl-Disiloxane with
1,5-Hexadiene by Karstedt Catalyst
RESULTS AND DISCUSSION
A 25 mL Schlenk flask equipped with a magnetic stir bar
was flushed with nitrogen. A solution of 1,5-hexadiene
(0.61 g, 7.4 mmol) and 1,1,3,3-tetramethyl-disiloxane (1.00 g,
7.4 mmol) was placed in the flask. After adding Karstedt
Mechanism of Hydrosilylation
In 1965, Chalk and Harrod suggested a mechanism for the
hydrosilylation reaction analogous to the transition metal-
catalyzed hydrogenation reaction (Scheme 2).17 The initial
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