Hydrosilylation of Allyl Ethers in the Presence of Platinum(II) Immobilized on Polymethylene Sulfide

Article abstract of DOI:10.1134/S1070363220010107

The reactions of allyl ethyl, allyl butyl, allyl glycidyl, allyl benzyl, and allyl phenyl ethers with 1,1,3,3-tetra-methyldisiloxane in the presence of platinum(II) immobilized on polymethylene sulfide have been studied.

Full text of DOI:10.1134/S1070363220010107

ISSN 1070-3632, Russian Journal of General Chemistry, 2020, Vol. 90, No. 1, pp. 68–77. © Pleiades Publishing, Ltd., 2020.
Russian Text © The Author(s), 2020, published in Zhurnal Obshchei Khimii, 2020, Vol. 90, No. 1, pp. 92–103.
Hydrosilylation of Allyl Ethers in the Presence
of Platinum(II) Immobilized on Polymethylene Sulfide
M. A. Il’inaa,* and D. A. de Vekkia
a St. Petersburg State Institute of Technology (Technical University), St. Petersburg, 190013 Russia
*e-mail: ilina_Masha@list.ru
Received July 10, 2019; revised July 10, 2019; accepted July 15, 2019
Abstract—The reactions of allyl ethyl, allyl butyl, allyl glycidyl, allyl benzyl, and allyl phenyl ethers with 1,1,3,3-tetra-
methyldisiloxane in the presence of platinum(II) immobilized on polymethylene sulfide have been studied.
Keywords: hydrosilylation, allyl ethers, tetramethyldisiloxane, immobilized platinum(II) complex, polymethylene
sulfide
DOI: 10.1134/S1070363220010107
Catalytic hydrosilylation of olefins is a key reaction
in the production of industrially important organosilicon
compounds generated in the presence of platinum com-
plexes. Since the price of platinum is high and unstable,
its repeated use is desirable, which is possible with
prolonged operation of the metal complexes. The use
of immobilized systems is among the approaches to the
stabilization of the catalytic properties and the multiple
use of the catalysts.
photomaterials [4], and the [Pt–PMS] complex revealed
good properties in vinylsiloxanes hydrosilylation [5].
In view of the rapid growth of the fields of organosili-
con compounds applications and, hence, the broadening
of the demanded substrates range, it was reasonable to
investigate the catalytic activity of [Pt–PMS] towards
hydrosilylation of allyl glycidyl (AllOGlyc), allyl phenyl
(AllOPh), allyl benzyl (AllOBn), allyl ethyl (AllOEt), and
allyl butyl (AllOBu) ethers with 1,1,3,3-tetramethyldisi-
locane. The AllOGlyc ether was of special importance
since epoxysilanes and epoxysiloxanes formed upon its
hydrosilylation was used as materials for electronics,
ship coatings, semipermeable membranes, materials with
reduced flammability, aerospace materials, etc. [6, 7].
Alarge variety of the supported platinum and rhodium
complexes have been developed, due to their wide use
and efficiency in olefins hydrosilylation [1–3]. Some
of the suggested methods are multistage and laborious,
which significantly increases their price and levels off
the advantages.
Hydrosilylation of allyl ethers with 1,1,3,3-tetrameth-
yldisiloxane in the presence of [Pt–PMS] occurs pre-
dominantly with the formation of the γ- and γ,γ-addition
Herein we studied the platinum(II) complex on a poly-
mer carrier (polymethylene sulfide [Pt–PMS]) (Scheme 1)
as an alternative supported catalyst. Polymethylene sul-
fide which is formed during oil purification of hydrogen
sulfide is an efficient complexing agent with sulfur atoms
uniformly distributed along the polymer chain and can
act as a macroligand (sulfide or alkylthiolate type). The
chemisorption of K2PtCl4 on polymethylene sulfide is
accompanied by the formation of the immobilized cis-
complex. Polymethylene sulfide has been successfully
used in certain regions of Russia as a sorbent of heavy
metals from used catalysts (gold, platinum, and pal-
ladium), tailings and wash waters of catalyst factories
(palladium and silver) as well as in the processing of
Scheme 1.
CH2
CH2
S
S
Pt
S
CH2
CH2
S
CH2
CH2
n
[Pt–PMS]
68

HYDROSILYLATION OF ALLYL ETHERS IN THE PRESENCE OF PLATINUM(II)
69
Scheme 2.
CH3
Si
CH3
Si
H
H
R
CH3
Si
CH3
Si
O
CH3
Si
CH3
Si
O
mCH3
CH3
[H]
R
H
H
H
+
H
+
O
O
O
O
CH3
CH3
n+1CH3
CH3
R
n
O
R
+
E
Z
CH3
Si
CH3
Si
', cat
H
CH3
CH3
Si
H
O
m–1 CH3
CH3
H
Si
H
CH3
CH3
CH3
Si
O
CH3
Si
CH3
n
R
CH3
O
Si
R
H
O
Si
H
O
O
CH3
nCH3
n
CH3
CH3
CH3
E-addition
J-addition
R
R
O
O
CH3
CH3
Si
CH3
CH3
R
Si
R
R
R
O
O
O
O
O
R
Si
CH3
J,J-addition
Si
O
CH3
nCH3
CH3
CH3
Si
CH3
CH3
n CH
O
R
Si
E,E-addition
O
O
CH3
n CH3
CH3
E,J-addition
CH
2
(
m, n = 1–4; mꢀ•ꢀn; R = Et, Bu, Glyc
), Bn, Ph.
O
products, i. e. via anti-Markovnikov addition of a single
or both SiH groups of the hydrosiloxane (Scheme 2). The
β-, β,β-, and β,γ-addition products are formed in much
lesser amount, which is typical of hydrosilylation in the
presence of platinum catalysts [8].
cyclization [15], etc.) did not occur in the presence of
the catalytic systems obtained by us.
Kinetic curves of the interaction of the allyl ethers
with (HMe2Si)2O were S-shaped, revealing the induction
period and the hydrosilylation stages differing in the rate
(Fig. 1). The induction period was likely related to the
poor availability of platinum in the complex with poly-
methylene sulfide; the subsequent low-rate stage was due
to slow formation of the true catalyst, and the high-rate
stage corresponded to accumulation of sufficient amount
of the catalytically active species.
On top of the major reaction, allyl ethers are prone
to the allyl-propenyl isomerization and reduction, and
1,1,3,3-tetramethyldisiloxane is disproportionated into
linear siloxanes НMe2Si(OSiMe2)nH (n = 2–4); moreover,
allyl ethers hydrosilylation with the formed siloxanes
НMe2Si(OSiMe2)nH occurs similar to hydrosilylation
with the starting (HMe2Si)2O. Such side transformation of
the allyl ethers and (HMe2Si)2O is in line with the general
features of hydrosilylation with homogeneous or hetero-
geneous platinum and rhodium complexes, whereas other
side reactions (epoxide cycle opening and formation of
glycidyl acrylate [9, 10], α-addition [8], dehydrogenative
silylation [11, 12], propene elimination [10], dimerization
and polymerization of ethers [8, 11, 13, 14], siloxanes
The induction period duration was related to the na-
ture of substituent R in the allyl etherAllOR, the catalyst
concentration, and temperature. The shortest induction
period was observed during hydrosilylation ofAllOGlyc
at 120°С (35 min, сPt = 3×10–3 mol/L) (Figs. 1 and 2,
Table 1). Decrease in the temperature by 20°С increased
the induction period by 10 min (45 min, 100°С), and the
decrease in the temperature to 80°С added further 10 min
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

70
Table 1. Hydrosilylation of allyl ethers with 1,1,3,3-tetramethyldisiloxane in the presence of [Pt–PMS]a
Catalyzate composition, %
product of (HMe2Si)2O
IL’INA, DE VEKKI
Conversion of γΣ-Selectivity,
Ether
Time, h Т, °С
γ/β, %
AllOR, %
%
addition
СН3СН=СНOR others
β-
γ- β,β- β,γ- γ,γ-
AllOBu
AllOEt
AllOBn
AllOPh
8.00
7.75
8.00
22.00
120
120
120
120
120
120
100
100
80
99
98
90
97
94
98
91
91
92
96.1
95.3
89.8
89.8
86.4
93.8
95.4
89.3
92.1
97.3/2.7 1.5 60.2 0.4 0.4 13.4
99.7/0.3 0.2 59.2 0.0 0.0 14.2
97.0/3.0 1.7 56.7 0.0 0.5 14.3
92.1/7.9 3.9 45.2 0.3 1.3 16.1
99.0/1.0 0.6 60.3 0.0 0.0 17.3
95.2/4.8 3.2 63.6 0.0 0.0 16.2
88.4/11.6 3.2 65.0 0.0 0.0 9.5
92.5/7.5 5.4 61.6 0.0 2.0 13.8
81.9/18.1 5.2 61.0 0.0 0.0 9.0
0.2
4.0
4.6
3.1
6.0
4.3
6.2
5.2
5.2
23.9
24.4
22.2
30.1
15.8
12.7
16.1
12
AllOGlyc 1.25
1.67b
2.30
6.50b
7.00
19.6
a cPt = 3×10–3 mol/L, ether : siloxane molar ratio = 1 : 1.5. b cPt = 3×10–4 mol/L.
to the induction period (55 min) (Fig. 2). Decrease in the
The highest conversion of AllOGlyc was reached
within 1.25 h (94%, 120°С, сPt = 3×10–3 mol/L), and
duration of its hydrosilylation (excluding the induction
period) was the shortest among the probed ethers (35‒
40 min). The decrease in the reaction temperature to
100°С increased the hydrosilylation duration by 2.4‒
2.7 times (95 min, conversion 91%, Fig. 2), further de-
crease in the temperature being even more critical (6 h,
conversion 92%, 80°С). The decrease in the [Pt–PMS]
concentration had weaker effect on the reaction rate in
comparison with temperature. The decrease in сPt by an
order of magnitude increased the hydrosilylation duration
by 1.5‒1.7 times at 120°С (60 min, conversion 98%), yet
the reaction duration was significantly increased at 100°С
(3.5 h, conversion 91%).
catalyst concentration by an order of magnitude increase
the induction period by 5 min at 120°С, and fivefold at
100°С (to 3 h). Hence, the optimal temperature for the
[Pt–PMS]-assisted hydrosilylation with 1,1,3,3-tetra-
methyldisiloxane was 100–120°С (сPt = 3×10–3 mol/L).
AllOGlyc hydrosilylation with polysiloxane containing
silicon hydride groups in the presence of Н2PtCl6 (the
Speier catalyst) occurs at close temperature (110‒130°С)
[16], whereas temperature optimal for hydrosilylation of
1,3-divinyl-1,1,3,3-tetramethyldisiloxane (HMe2Si)2O on
[Pt–PMS] was significantly lower (55°С; the decrease
in temperature to 45°С has led to the appearance of the
induction period) [5].
The induction period during hydrosilylation ofAllOEt
and AllOBu was significantly longer than for AllOGlyc:
5 and 6.75 h, respectively (120°С, сPt = 3×10–3 mol/L).
The induction period duration was strongly affected by the
distance between the phenyl ring and the allyl group: the
induction period during hydrosilylation ofAllOPh was the
longest (20 h, 120°С, сPt = 3×10–3 mol/L), whereas that
during the interaction between AllOBn and 1,1,3,3-tet-
ramethyldisiloxane was close to the induction period for
AllOEt (5.5 h, 120°С, сPt = 3×10–3 mol/L). Hence, the
induction period during the hydrosilylation was shortened
over the following ethers series: AllOPh >> AllOBu >
AllOBn > AllOEt >> AllOGlyc.
The maximum conversion of AllOBu (99%, 8 h,
120°С) was higher than that ofAllOGlyc, and the hydro-
silylation occurred within 1.25 h (excluding the induction
period) (Table 1). Hydrosilylation of AllOEt was slower
(~2 h), and the conversion upon the reaction completion
(7 h) reached 94% (Figs. 1 and 3). Kinetic curve of the
AllOBn hydrosilylation was practically identical to that of
AllOEt (reaction duration of 2 h). The slope of the hydro-
silylation kinetic curve and, hence, the reactivity of allyl
phenyl ether was the lowest among the studied ethers.
Hence, the allyl ethers reactivity in the hydrosilylation
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

HYDROSILYLATION OF ALLYL ETHERS IN THE PRESENCE OF PLATINUM(II)
71
Time, h
Time, h
Fig. 2. Kinetics of the change in allyl glycidyl ether conversion
during its interaction with (НMe2Si)2O in the presence of
[Pt–PMS] (ether : siloxane molar ratio = 1 : 1.5) at cPt = 3×10–3
(1, 3, 4), 3×10–4 mol/L (2, 5). (1, 2) 120°С, (3, 5) 100°С, and
(4) 80°С.
Fig. 1. Kinetics of the change in ethers conversion during their
interaction with (НMe2Si)2O in the presence of [Pt–PMS]
(cPt = 3×10–3 mol/L, ether : siloxane molar ratio = 1 : 1.5, 120°С).
(1) AllOGlyc, (2) AllOEt, (3) AllOBn, (4) AllOBu, and
(5) AllOPh.
was decreased along the following series: AllOGlyc >
AllOBu > AllOEt ≈AllOBn > AllOPh.
Isomerization of AllOEt was much more prominent
than for AllOBu. The fraction of the propenyl ethyl
ethers upon the reaction completeness was higher than
that of propenyl butyl ethers by 20 times (4.0%), propyl
ethyl ether was not formed. In its turn, isomerization
and reduction of AllOBn was twofold faster than those
of AllOEt (8.0% in total, 8 h, 120°С), which reduced the
selectivity ofAllOBn hydrosilylation in comparison with
AllOEt and AllOBu.
Allyl-propenyl isomerization and reduction of allyl
ethers accompanying the hydrosilylation was determined
by the nature of the R substituent in theAllOR ether. The
highest yield of the geometry isomers of the propenyl
ethers was observed for AllOGlyc. When the hydrosi-
lylation was complete, the fraction of the propenyl gly-
cidyl ethers was as high as 6.0%; the decrease in neither
the reaction temperature nor [Pt–PMS] concentration led
to significant decrease in the side products amount. The
fraction of the reduction product (propyl glycidyl ether)
was also relatively high (3.6%) and was independent of
the reaction temperature and catalyst concentration. The
side reactions of AllOGlyc were in line with its high
reactivity.
Side transformations of AllOPh were limited to the
formation of propenyl phenyl ethers (3.1%); probably,
they were formed in larger amount but were consumed
Hydrosilylation ofAllOBu led to the formation of only
trace amounts of the isomerization and reduction products
(120°С); their fraction did not exceed 0.2% upon the
reaction completion. The yield of propenyl butyl ethers
upon the induction period reached 0.9%. The decrease
in the propenyl ethers yield during the hydrosilylation is
typical of other allyl ethers as well and is due to their con-
sumption for the hydrosilylation into the β-adduct [17].
Hence, the reaction selectivity is reduced. However, the
low concentration of the propenyl ethers in the presence of
[Pt–PMS] and the lower activity of the endo-С=С bonds
in the hydrosilylation in comparison with the terminal
ones [14, 18–20] led to suggestion of insignificant con-
tribution of the propenyl ethers hydrosilylation.
Time, min
Fig. 3. Kinetics of the change in ethers conversion after the
induction period during their interaction with (НMe2Si)2O in
the presence of [Pt–PMS] (cPt = 3×10–3 mol/L, ether : siloxane
molar ratio = 1 : 1.5, 120°С). (1) AllOGlyc, (2) AllOBu,
(3) AllOEt, (4) AllOBn, and (5) AllOPh.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

72
IL’INA, DE VEKKI
Table 2. Yield of НMe2Si(OSiMe2)nH (n = 2‒4) in hydrosilylation of allyl ethers with 1,1,3,3-tetramethyldisiloxane in the pres-
ence of [Pt–PMS]a
n = 2
n = 3
n = 4
Т, °С
Ether
Time, h
A
1.9
0.3
1.2
0.3
4.5
0.3
4.7
0.3
1.9
0.0
10.7
9.3
3.3
14.4
1.2
6.7
0.6
42.6
18.8
B
A
B
A
B
80
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOGlyc
AllOBu
1.00
7.00
0.75
2.30
3.00b
6.50b
0.50
1.15
0.67b
1.67b
5.00
6.75
7.00
5.00
7.75
5.50
9.00
20.00
22.00
1.9
0.3
2.0
0.2
1.9
1.7
1.2
1.2
0.9
0.5
0.6
3.7
6.3
1.7
2.9
1.5
5.3
0.8
1.9
0.6
0.3
3.8
0.2
3.6
1.7
2.9
1.2
3.1
0.5
1.4
3.7
6.3
3.5
3.3
3.1
5.3
2.1
1.9
5.9
0.0
0.3
0.0
0.2
0.6
0.2
0.0
0.1
0.0
0.7
1.1
1.8
0.6
0.3
0.4
0.7
0.2
0.6
0.4
0.0
0.4
0.0
0.4
0.6
0.5
0.0
0.1
0.0
0.8
1.1
2.1
0.9
0.3
0.4
0.7
1.1
0.6
2.2
80
2.2
100
100
100
100
120
120
120
120
120
120
120
120
120
120
120
120
120
1.2
2.2
4.5
2.3
4.7
3.3
1.9
3.1
10.7
11.8
13.1
15.6
14.8
7.1
AllOBu
AllOBu
AllOEt
AllOEt
AllOBn
AllOBn
11.7
43.8
27.7
AllOPh
AllOPh
a сPt = 3×10–3 mol/L, ether : siloxane molar ratio = 1 : 1.5. A—yield of free siloxane НMe2Si(OSiMe2)nH, B—total yield of free siloxane
НMe2Si(OSiMe2)nH and siloxane bound into hydrosilylation products. b сPt = 3×10–4 mol/L.
for hydrosilylation into the β-adduct, coinciding with low
regioselectivity of AllOPh hydrosilylation.
prominent, due to the shortest induction period and the
overall duration of the target reaction. The total yield
of the formed НMe2Si(OSiMe2)nH, in view of their
consumption for the interaction with AllOGlyc, upon
the hydrosilylation completeness was 3.3, 3.1, and 0.1%
(n = 2, 3, and 4 respectively, 1.15 h at 120°С, Table 2). The
decrease in temperature by 20°С reduced the trisiloxane
yield to 2.2%, but the total yield of НMe2Si(OSiMe2)3H
and НMe2Si(OSiMe2)4H was increased. As a result, the
total amount of the products of side transformation of
the starting siloxane was only slightly decreased (by
0.5%). Further decrease in temperature by 20°С (to 80°С)
practically did not affect the total yield of the products
Another side reaction accompanying the hydrosi-
lylation is the disproportionation of the starting hydrosi-
loxane into НMe2Si(OSiMe2)nH (n= 2‒4) which are prone
to hydrosilylation of the allyl ether, the products fraction
being up to 30%. The major part of НMe2Si(OSiMe2)nH
is formed during the induction period, depending on the
induction period duration, temperature, and the metal
complex concentration, and is indirectly related to the re-
activity of the ether affecting the target reaction duration.
Side transformations of 1,1,3,3-tetramethyldisilox-
ane during AllOGlyc hydrosilylation were the least
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

HYDROSILYLATION OF ALLYL ETHERS IN THE PRESENCE OF PLATINUM(II)
73
of (НMe2Si)2O side transformations. The decrease in
[Pt–PMS] concentration by an order of magnitude re-
duced the total yield of НMe2Si(OSiMe2)3H by 1.5 times
at 100°С (Table 2).
The addition of (HMe2Si)2O to AllOBu showed long
induction period and the hydrosilylation duration, and
the disproportionation was more prominent than in the
case of AllOGlyc, allowing to monitor the dynamics of
formation and consumption of the side siloxanes. The
yield of НMe2Si(OSiMe2)2H, НMe2Si(OSiMe2)3H, and
НMe2Si(OSiMe2)4H was 10.7, 3.7, and 1.1%, (after
5 h at 120°С) and 9.3, 6.3, and 1.8% (after 6.75 h), re-
spectively, i. e. НMe2Si(OSiMe2)2H was consumed and
НMe2Si(OSiMe2)3H was accumulated. When AllOBu
was completely consumed, the yield of the side siloxanes
was 3.3, 1.7, and 0.6%, due to their consumption in the hy-
drosilylation. Those processes are better illustrated by the
kinetic curves (Fig. 4). For example, the kinetic curve of
НMe2Si(OSiMe2)2H accumulation showed initial smooth
growth, followed by steep decrease at certain concentra-
tion of the metal complex sites (the end of the induction
period) at the high-rate hydrosilylation stage and then by
smooth increase again. Only trace amount of theAllOBu
hydrosilylation with 1,1,3,3,5,5-hexamethyltrisiloxane
was formed during the induction period as reflected in the
corresponding kinetic curve, followed by steep accumula-
tion of the product (high-rate hydrosilylation) and leveling
off (completeness of the hydrosilylation). Kinetic curve of
the change in the total amount of free and hydrosilylated
1,1,3,3,5,5-hexamethyltrisiloxane [it was impossible to
determine the consumption of НMe2Si(OSiMe2)2H for
disproportionation] revealed smooth growth over the
whole reaction duration. The curves of accumulation
and consumption of НMe2Si(OSiMe2)nH (n = 3, 4) were
similar; total yield of НMe2Si(OSiMe2)nH (accounting
for the hydrosilylation) was 13.1, 3.5, and 0.9% (n = 2,
3, and 4, respectively; Table 2).
Time, min
Fig. 4. Kinetics of the change in yield of НMe2Si(OSiMe2)2H
during the interaction of AllOBu with (HMe2Si)2О in the
presence of [Pt–PMS] (cPt = 3×10–3 mol/L, 120°С). (1) total
yield of free siloxane and siloxane bound in the hydrosilylation
products; (2) yield of the bound siloxane; and (3) yield of the
free siloxane.
(22 h), the yield of НMe2Si(OSiMe2)nH accounting for
their consumption for hydrosilylation was 27.7, 5.9, and
2.2% (n = 2, 3, and 4, respectively). The decrease in the
fraction of НMe2Si(OSiMe2)2H was not proportional to
the increase in the amount of НMe2Si(OSiMe2)3H and
НMe2Si(OSiMe2)4H, likely due to the higher reactivity
of the former in comparison to НMe2Si(OSiMe2)3H and
НMe2Si(OSiMe2)4H as well as its disproportionation into
(HMe2Si)2O and НMe2Si(OSiMe2)3H [8].
Hence, the duration of the induction period and the
hydrosilylation itself were the major factors affecting
the amount of the side siloxanes and the allyl-propenyl
isomerization of the allyl ethers.
The presence of the second Si–H group in the mono-
adducts allowed their interaction with the allyl ether to
form the products of double addition even in the excess
of (НMe2Si)2O. Hydrosilylation of AllOGlyc, due to the
ether high reactivity, gave exclusively the γ,γ-adduct, its
fraction being 17.3% at 120°С. The temperature decrease
reduced its amount almost twofold (the γ,γ-adduct frac-
tion was 9.5 and 9.0% at 100 and 80°С, respectively).
The accumulation of free НMe2Si(OSiMe2)nH dur-
ing the induction period and their consumption for the
hydrosilylation was typical also of AllOEt and AllOBn
reactions, the total yield of the siloxanes upon the reac-
tion being practically equal to that for AllOBu (Table 2).
The yield of the γ,γ-addition product during theAllO-
Bu interaction with (НMe2Si)2O was lower (13.4%) than
for AllOGlyc, yet the products of β,β- and β,γ-addition
were detected (yield <0.8%). The amount of the AllOEt
and AllOBn hydrosilylation with the Si–H group of the
monoadducts when the major reaction was complete was
only slightly different from that in the case of AllOBu
(14.2 and 14.8% for AllOEt and AllOBn, respectively),
but hydrosilylation ofAllOBn gave γ,γ- and β,γ-adducts,
The longest induction period for the hydrosilylation
of AllOPh led to the most prominent side transforma-
tion of hydrosiloxanes as compared to other ethers.
When the induction period was complete, the yield of
НMe2Si(OSiMe2)nH was 42.6, 3.5, and 1.0% (n = 2, 3,
and 4, respectively; Table 2). Upon the major reaction
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

74
IL’INA, DE VEKKI
the γ,γ-adduct being exclusively formed in the case of
AllOEt (Table 1).
products of double addition) in order to extrapolate the
obtained data to hydrosilylation with oligomeric and
polymeric silicon hydrides (in those cases the dispropor-
tionation has practically no effect on the average molecu-
lar mass and the properties of the reaction product) was
estimated as of 96.1 and 95.3% for AllOBu and AllOEt
hydrosilylation, respectively, about 36% higher than the
selectivity of (HMe2Si)2O addition. γΣ-Selectivity of
AllOGlyc, AllOBn, and AllOPh hydrosilylation was
of 86.4, 89.8, and 89.8%, respectively. However, the
selectivity in the case of [Pt-PMS] or homogeneous
cyclooctadiene (85%), dibenzyl sulfide (87%), and di-
methyl sulfoxide (84%) platinum complexes was lower
than in the case of the Wilkinson catalyst [Rh(Ph3P)3Cl]
(95%) [14]. The γΣ-selectivities calculated from the GLC
and 1Н NMR data were in agreement [it was impossible to
determine the selectivity of hydrosilylation exclusively of
the product of (HMe2Si)2O γ-addition from the 1Н NMR
data due to the overlap of the signals of the products of
hydrosilylation with the starting hydrosiloxane and the
side hydrides НMe2Si(OSiMe2)nH (n = 2, 3)].
The amounts of the products of double addition during
AllOPh andAllOGlyc hydrosilylation were comparable,
being higher than for other ethers (17.7%). The β,γ-adduct
yield was 2‒3 times higher than for hydrosilylation of
AllOBu andAllOBn, whereas the β,β-adduct was formed
in trace amount.
Hydrosilylation of the allyl ethers with the formed
monoadducts bearing free SiH group was much slower
than with 1,1,3,3-tetramethyldisiloxane, and the targeted
preparation of the double addition products demanded
the excess of the allyl ether and considerable reaction
duration. The same has been observed for comparative
hydrosilylation of aliphatic ethers terephthaloyl bis(4-
hydroxybenzoates) with 1,1,3,3-tetramethyldisiloxane
and 1-(1'-arylethoxy)-1,1,3,3-tetramethyldisiloxane [21].
Selectivity of allyl ethers hydrosilylation is usually
regarded as the ratio between the γ- and β-adducts (regi-
oselectivity) disregarding the side reactions. In this study,
regioselectivity of (HMe2Si)2O addition during hydrosi-
lylation of AllOGlyc and AllOEt was close to the maxi-
mum—99.0 and 99.7%, respectively (сPt = 3×10–3 mol/L,
120°С). The ratio between products of γ- and β-addition
of (HMe2Si)2O during hydrosilylation of AllOBu and
AllOBn was close (97.3 and 97.0%, respectively), being
lower (92.1%) only for AllOPh.
The possibility of repeated use is an important feature
of the immobilized metal complexes. Platinum(II) immo-
bilized on PMS withstood at least 10 cycles of AllOGlyc
hydrosilylation (120°С, сPt = 3×10–3 mol/L);TONAllOGlyc
>
8550, TOFAllOGlyc = 3.5683 s–1, TOFAllOBu = 0.9416 s–1,
TOFAllOEt = 0.1283 s–1, TOFAllOBn = 0.1121 s–1, and
TOFAllOPh = 0.1022 s–1. The duration of the catalyst con-
tact with the reaction mixture should have been increased
after the 3rd cycle to preserve high conversion of the ether
(Table 3). The decrease in temperature to 80°С negatively
affected the number of productive cycles (due to low
activity of the catalyst), coinciding with the data in Refs.
[22, 23]. The repeated use of the [Pt–PMS] complex was
comparable to silica-immobilized Pt(0) bearing ethylene
oxide fragments [24]. The [Pt–PMS] complex withstood
four cycles during hydrosilylation of 1,3-divinyl-1,1,3,3-
tetramethyldisiloxane with 1,1,3,3-tetramethyldisiloxane
[5].
Selectivity of the reaction [the ratio between the
product of γ-addition (HMe2Si)2O to all the compounds
formed fromAllOR, including the side reactions products
and the products of mono- and bis-addition of the side
siloxanes НMe2Si(OSiMe2)nH (n = 2–4) to AllOR] was
lower than the regioselectivity (45.2‒60.3% at 120°С)
due to the formation of the double addition products and
high reactivity of НMe2Si(OSiMe2)nH (Table 1). It could
be suggested that the low selectivity of AllOR hydrosi-
lylation was majorly due to the induction period; however,
the selectivity of the AllOGlyc reaction at 120°С was
close to that of other ethers despite the shortest induction
period, due to side reactions of AllOGlyc and significant
formation of the product of the γ,γ-addition (60.3%); the
decrease in temperature increased the selectivity (65%).
As in the case of (HMe2Si)2O addition, selectivity of the
reaction for AllOPh was the lowest among the studied
ethers (45.2%).
Selectivity of the reaction, its regioselectivity and,
γΣ-selectivity remained practically unchanged during
repeated use of [Pt–PMS] (Table 3); the amount of side
products of siloxanes and ethers transformations remained
the same as well. Washing of the catalyst with methylene
chloride did not affect the reaction selectivity.
To understand the mechanism of catalytic action of
[Pt–PMS], we studied the effect of the prior treatment of
the catalytic complex with 1,1,3,3-tetramethyldisiloxane
Total γ-addition (γΣ-selectivity) accounting for the
contribution of all the γ-adducts formed during hydro-
silylation (including that with side siloxanes and the
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

HYDROSILYLATION OF ALLYL ETHERS IN THE PRESENCE OF PLATINUM(II)
75
Table 3. Repeated using of [Pt–PMS] in hydrosilylation of allyl glycidyl ether with 1,1,3,3-tetramethyldisiloxanea
Product of (HMe2Si)2O
γΣ-
Cycle Т,
Conversion of
AllOGlyc, %
СН3СН=СНOGlyc, Others,
addition, %
Time, h
Selectivity, γ/β, %
%
no.
°С
%
%
β-
γ-
β,γ- γ,γ-
9.3
1
2
3
4
5
6
1
2
3
4
80
80
7.00
7.00
7.00
7.00
7.00
7.00
1.25
1.25
1.25
1.25
2.00
2.50
2.50
3.00
6.00
7.50
7.50
92
94
90
59
56
33
99
99
94
84
99
97
97
94
92
96
95
93.3
92.5
98.8
92.1
92.0
93.1
96.0
96.5
95.8
94.9
96.0
95.5
96.7
96.9
96.0
95.5
95.0
92.1/7.9 5.3 62.6 0.0
5.4
4.9
5.6
6.5
7.7
6.1
5.6
5.7
6.1
5.8
3.7
3.4
5.0
5.2
5.3
5.1
3.8
17.4
17.4
14.0
9.2
91.0/1.0 6.1 61.6 0.0 10.0
98.6/1.4 1.0 67.6 0.0 11.8
90.8/9.2 6.6 65.7 0.0 12.0
91.7/8.3 5.9 65.0 1.0 11.8
80
80
80
8.6
80
91.9/8.1 6.2 70.4 0.0
95.5/4.5 2.8 58.5 0.0
8.6
9.3
8.7
120
120
120
120
120
120
120
120
120
120
120
23.8
20.7
20.8
21.6
11.7
10.3
13.0
12.8
11.5
13.7
17.0
95.8/4.2 2.5 57.6 0.7 12.7
96.3/3.7 2.1 53.0 0.8 17.1
94.4/5.6 3.3 55.6 1.3 12.5
94.8/5.2 3.6 66.0 0.0 15.0
93.9/6.1 4.1 63.5 0.0 18.7
94.8/5.2 2.9 53.1 0.0 26.0
93.4/6.6 2.7 38.6 0.0 40.7
93.7/6.3 3.6 53.0 0.0 26.7
93.1/6.9 4.0 54.1 0.0 23.1
92.8/7.2 4.4 56.1 0.0 18.7
5
6
7
8
9
10
a сPt = 3×10–3 mol/L, ether : siloxane molar ratio = 1 : 1.5.
or AllOGlyc (2 h, 80°С) followed by hydrosilylation
on the obtained interaction product. The pre-activation
of [Pt–PMS] with 1,1,3,3-tetramethyldisiloxane was
accompanied by the change in the solution color from
colorless to yellow-green, typical of the formation of
platinum-silicon hydride complexes [25].
AllOGlyc at room temperature (18‒25°С) was compa-
rable to that of the starting [Pt–PMS], however, if the
addition of AllOGlyc upon the treatment was performed
at higher temperature (30‒40°С), conversion of the ether
(80% after 2 h at 80°С) was significantly increased in
comparison with simultaneous addition of the reactants
(29%).Asimilar trend of the increase in alkene conversion
via pre-activation of homogeneous cis-[Pt(Me2SO)2Cl2],
cis-[Pt(Et2SO)2Cl2], and [Pt(MeCOD)Cl2] catalysts with
1,1,3,3-tetramethyldisiloxane has been observed during
hydrosilylation of α-methylstyrene [27], suggesting the
common mechanism. Pre-activation of [Pt–PMS] with
1,1,3,3-tetramethyldisiloxane positively affected the se-
lectivity of hydrosilylation: the amount of the products
of (НMe2Si)2O γ-addition to AllOGlyc was increased
(the γ/β-adducts ratio being 92.8/7.2); the hydrosilylation
selectivity was up by 5.8%, the γΣ-selectivity was up by
1.2%; the amounts of the products of side transforma-
IR spectrum of the specimen obtained via the treat-
ment with 1,1,3,3-tetramethyldisiloxane and washing
of the complex with CH2Cl2 contained two bands of
the siloxane methyl groups at 804 and 1259 cm–1, and a
new band appearing at 1093 cm–1 could be assigned to
the νas(Si‒O‒Si) stretching, the ν(Si‒H) signal at 2300‒
2400 cm–1 being absent. The change in the IR spectrum
of [Pt–PMS] upon the treatment with 1,1,3,3-tetrameth-
yldisiloxane were likely due to the oxidative addition of
the silicon hydride to form the Pt–Si bond [25, 26].
Catalytic activity of [Pt–PMS] upon the treatment
with 1,1,3,3-tetramethyldisiloxane and addition of
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

76
IL’INA, DE VEKKI
tions of AllOGlyc was decreased (the fraction of the
propenyl and propyl glycidyl ethers being 3.3 and 3.2%,
respectively).
225°С at 25 deg/min, 45 min at 225°С, carrier gas: helium
with 1 : 250 splitting.
IR spectra were recorded using a Shimadzu FTIR-
8400S spectrometer (4000‒400 cm–1) in KBr pellets.
The pre-treatment of [Pt–PMS] with AllOGlyc deac-
tivated the complex. Further addition of the siloxane to
the so treated sample led to the ether conversion as low
as 2% after 2 h at 80°С, probably due to the formation of
an inefficient π-allyl complex; however, the IR spectrum
of the catalyst was not changed upon the treatment with
AllOGlyc. Pre-activation of homogeneous sulfur-
containing complexes, cis-[Pt(Me2SO)2Cl2] and cis-
[Pt(Et2SO)2Cl2], has significantly decelerated the hydro-
silylation of α-methylstyrene as well [27].
Hydrosilylation of allyl ethers was performed in
ampoules at 80‒120°С. Weighed amount of the catalyst
was charged into an ampoule, and a mixture of the si-
loxane, allyl ether, and toluene (molar ratio 6 : 4 : 1 was
added); platinum concentration in the reaction mixture
was 3×10–4–3×10–3 mol/L at сPt = 8×10–5 mol/g with
respect to the carrier. Conversion and selectivity were
determined by means of GLC (kinetic method) using
toluene as internal reference as described elsewhere [3].
Analysis of the obtained data in view of earlier
studies [3, 5] and the existing concepts of the hydrosi-
lylation mechanism suggested that the key stage of the
reaction was the primary interaction of [Pt–PMS] with
(НMe2Si)2O. Subsequent attack of the allyl group afford-
ing the corresponding intermediate (introduction at the
Pt–Si bond) led to hydrosilylation, whereas other trans-
formations of the silicon complex of platinum activated
the side processes involving hydrosiloxanes. The inter-
mediate formation was affected by the siloxane and allyl
ether structure and led to the induction period observed
for certain systems. In its turn, primary coordination of
the allyl ether was the major reason for isomerization of
its double bond or the reduction upon the attack of the
intermediate with hydrosiloxane.
FUNDING
This study was supported by the Ministry of Science and
Higher Education of Russian Federation in the scope of the
State Task (11.5362.2017/8.9) and the complex project for
the creation of high-technology production, Ministry of Sci-
ence and Higher Education of Russian Federation (agreement
no. 03.G25.31.0237).
CONFLICT OF INTEREST
No conflict of interest was declared by the authors.
REFERENCES
1. Advances in Silicon Science, Marciniec, B., Ed.,
London: Springer, 2009, vol. 1, p. 32.
https://doi.org/10.1007/978-1-4020-8172-9
EXPERIMENTAL
2. de Vekki, D.A., Il’ina, M.A., and Skvortsov, N.K.,
Izv. SpbGTI(TU), 2015, no. 32(58), p. 54.
1,1,3,3-Tetramethyldisiloxane and allyl glycidyl
ether (Acros), allyl butyl, allyl phenyl, and allyl benzyl
ethers (Aldrich), allyl ethyl ether (Fluka), and toluene
and methylene chloride (“analytical pure” grade) were
used. The [Pt–PMS] complex was obtained as described
elsewhere [5].
https://doi.org/10.15217/issn998984-9.2015.32.54.
3. de Vekki, D.A., Il’ina, M.A., and Skvortsov, N.K., Russ.
J. Gen. Chem., 2018, vol. 88, no. 1, p. 25.
https://doi.org/10.1134/S107036321801005X
4. Gafiatullin, R.R., Candidate Sci. (Tech.) Dissertation,
Priyutovo, 2000.
Chromatographic analysis of the hydrosilylation
products was performed using an Agilent 7890A chro-
matograph equipped with a heat conductivity detector.
Other conditions were as follows: capillary column DB-1
(30 m×0.32 mm, phase film thickness 1 μm), specimen
volume 0.5 μL, evaporator temperature 250°С; for the
reaction mixtures based on AllOPh and AllOBn: col-
umn temperature 150°С (4 min), heating to 290°С at
42 deg/min, 35 min at 290°С, carrier gas: helium with
1 : 300 splitting; for the reaction mixtures based on
AllOEt, AllOBu, and AllOGlyc: column temperature
70°С (5 min), heating to 200°С at 5 deg/min, heating to
5. de Vekki, D.A., Kuchaev, E.A., Afonin, M.V., and Sima-
nova, S.A., Russ. J. Gen. Chem., 2008, vol. 78, no. 4,
p. 575.
https://doi.org/10.1134/S1070363208040105
6. Il’ina, M.A., Mashlyakovskii, L.N., Drinberg A.S,
Khomko, E.V., and Garabadzhiu, A.V., Russ. J. Appl.
Chem., 2019, vol. 92, no. 4, p. 530.
https://doi.org/10.1134/S0044461819040091
7. Chrusciel, J.J. and Lesniak, E., Prog. Polym. Sci., 2015,
vol. 41, p. 67.
https://doi.org/10.1016/j.progpolymsci.2014.08.001
8. Il’ina, M.A., de Vekki, D.A., and Skvortsov, N.K., Russ.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020

HYDROSILYLATION OF ALLYL ETHERS IN THE PRESENCE OF PLATINUM(II)
J. Gen. Chem., 2014, vol. 84, no. 1, p. 40.
p. 93.
77
https://doi.org/10.1134/S1070363214010095
18. Comprehensive Handbook on Hydrosilylation, Mar-
ciniec, B., Ed., Oxford: Pergamon Press, 1992.
19. Andrianov, K.A., Souček, J., and Khananashvili, L.M.,
Russ. Chem. Rev., 1979, vol. 48, no. 7, p. 657.
https://doi.org/10.1070/RC1979v048n07ABEH002390
20. Zuev, V.V. and de Vekki, D.A., Russ. J. Org. Chem.,
2006, vol. 42, no. 8, p. 1108.
https://doi.org/10.1134/S107042800608001X
21. Rozga-Wijas, K., Chojnowski, J., Fortuniak, W.,
Scibiorek, M., Michalska, Z., and Rogalski, L., J. Mater.
Chem., 2003, vol. 13, p. 2301.
9. Safa, K.D., Bahadori, A., Tofangdarzadeh, S., and
Nasirtabrizi, M.H., J. Iran. Chem. Soc., 2008, vol. 5,
no. 1, p. 37.
https://doi.org/10.1007/BF03245813
10. Chernyshev, E.A., Belyakova, Z.V., Knyazeva, L.K., and
Khromykh, N.N., Russ. J. Gen. Chem., 2007, vol. 77,
no. 1, p. 55.
https://doi.org/10.1134/S1070363207010082
11. Marciniec, B., Walczuc, E., Blazejewska-Chadyniak, P.,
Kujawa-Welten, M., and Krompiec, S., Organosilicon
Chem., 2003, p. 415.
https://doi.org/10.1002/9783527619924.ch67
12. Belyakova, Z.V., Pomerantseva, M.G., Efimova, L.A.,
Chernyshev, E.A., and Storozhenko, P.A., Russ. J. Gen.
Chem., 2010, vol. 80, no. 4, p. 728.
https://doi.org/10.1039/B304134D
22. Marciniec, B., Maciejewski, H., Szubert, K., and
Kurdykowska, M., Monatsh. Chem., 2006, vol. 137, no. 5,
p. 605.
https://doi.org/10.1007/s00706-006-0461-9
23. Maciejewski, H., Szubert, K., Marciniec, B., and Per-
nak, J., Green Chem., 2009, vol. 11, no. 7, p. 1045.
https://doi.org/10.1039/b819310j
https://doi.org/10.1134/S1070363210040079
13. Feng, S. and Cui, M., React. Funct. Polym., 2000, vol. 45,
no. 2, p. 79.
24. Alauzun, J., Mehdi, A., Reye, C., and Corriu, R.,
Chem. Matter., 2007, vol., 19, no. 26, p. 6373.
https://doi.org/10.1021/cm7019087
25. Huang, J., Liu Zh., Liu, X., He Ch., Chow Sh.Y., and
Pan, J., Langmuir, 2005, vol. 21, no. 2, p. 699.
https://doi.org/10.1021/la0482148
https://doi.org/10.1016/S1381-5148(00)00013-4
14. Andreev, S.A., Il’ina, M.A., Volkova, A.M., de Vekki, D.A.,
and Skvortsov, N.K., Russ. J. Appl. Chem., 2010,
vol. 83, no. 11, p. 1962.
https://doi.org/10.1134/S1070427210110133
15. de Vekki, D.A. and Skvortsov, N.K., Russ. J. Gen. Chem.,
2009, vol. 79, no. 4, p. 598.
26. Stein, J., Lewis, L.N., Gao, Y., and Scott, R.A.,
J.
Am. Chem. Soc., 1999, vol. 121, no. 15, p. 3693.
https://doi.org/10.1134/S107036320904015X
16. Wang, W., Eur. Polym. J., 2003, vol. 39, no. 6, p. 1117.
https://doi.org/10.1016/S0014-3057(02)00374-9
17. Schilling, C.L., J. Organomet. Chem., 1971, vol. 29, no. 1,
https://doi.org/10.1021/ja9825377
27. Petrenko, M.Yu., de Vekki, D.A., and Skvortsov, N.K., Izv.
SpbGTI(TU), 2009, no. 5(31), p. 53.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 90 No. 1 2020