C- and Si-substituted benzyl(ethynyl)silanes

Article abstract of DOI:10.1007/s11176-008-1013-2

Hitherto unknown mono-, di, and triethynyl C- and Si-substituted benzylsilanes were synthesized by the reaction of benzylmagnesium halides with dialkyl(ethynyl)fluorosilanes and of benzyldichloro(hydrocarbyl) silane and benzyltrichlorosilane with ethynylm

Full text of DOI:10.1007/s11176-008-1013-2

ISSN 1070-3632, Russian Journal of General Chemistry, 2008, Vol. 78, No. 1, pp. 69 72.
Pleiades Publishing, Ltd., 2008.
Original Russian Text L.V. Zhilitskaya, N.K. Yarosh, N.O. Yarosh, M.G. Voronkov, 2008, published in Zhurnal Obshchei Khimii, 2008, Vol. 78, No. 1,
pp. 72 75.
C- and Si-Substituted Benzyl(Ethynyl)Silanes
L. V. Zhilitskaya, N. K. Yarosh, N. O. Yarosh, and M. G. Voronkov
Favorskii Irkutsk Institute of Chemistry, Siberian Branch, Russian Academy of Sciences,
ul. Favorskogo 1, Irkutsk, 664033 Russia
e-mail: voronkov@irioch.irk.ru
Received May 10, 2007
Abstract Hitherto unknown mono-, di, and triethynyl C- and Si-substituted benzylsilanes were synthesized
by the reaction of benzylmagnesium halides with dialkyl(ethynyl)fluorosilanes and of benzyldichloro(hydro-
carbyl)silane and benzyltrichlorosilane with ethynylmagnesium bromide. The IR and NMR spectra of all new
compounds were studied.
DOI: 10.1134/S1070363208010131
Earlier we described 4-substituted phenyl(ethy-
nyl)methylfluorosilanes [1], aryldimethyl(ethynyl)-
silanes [2] and (arylpropyl)(ethynyl)dimethylsilanes
[3, 4].
reactions of benzyl(hydrocarbyl)dichlorosilanes with
ethynylmagnesium bromide (1:2) in THF in 67 and
66% yields, respectively.
Similarly, by the reaction of benzyltrichlorosilane
with ethynylmagnesium bromide (1:3) we synthe-
sized benzyl(triethynyl)silane (X) in 54% yield.
Developing investigations in this direction, we
have studied the reaction of benzylmagnesium halides
with dialkyl(ethynyl)fluorosilane as well as the reac-
tions of benzyl(hydrocarbyl)dichlorosilane and benzyl-
trichlorosilane with ethynylmagnesium bromide. In
both cases, previously unknown derivatives of benzyl-
(ethynyl)silanes were obtained.
C6H5CH2SiCl3 + 3BrMgC CH
C6H5CH2Si(C CH)3 + 3MgClBr.
X
The reaction of 2- or 4-substituted benzylmagne-
sium halides with dialkyl(ethynyl)fluorosilanes in a
1:1 molar ratio in ether or THF gives rise to exo-
substituted benzyl(ethynyl)dialkylsilanes of the
general formula YC6H4CH2Si(C CH)R2 (I VII).
As by-products of the ethynylation reaction, poly-
unsaturated compounds of the
general formula
PhCH2(HC C)n 1RSiC=CSiR(C CH)n 1CH2Ph
containing three or five triple bonds, probably formed
via bis(bromomagnesio)acetylene, were isolated in
8% yield. In the NMR spectra, the 13C (sp) signals of
the endo-SiC CSi fragment are at 108.01 and
107.97 ppm, respectively (cf. 113.02 ppm in bis(tri-
methylsilyl)acetylene [5]).
Y-C6H4CH2MgX + FSi(C CH)R2
Y-C6H4CH2Si(C CH)R2 + MgXF,
I VII
Y = H, X = Cl, R = Me (I); Y = H, X = Cl, R = Et (II);
Y = 4-F, X = Br, R = Me (III); Y = 4-Cl, X = Br, R = Me
(IV); Y = 4-Me, X = Br, R = Me (V); Y = 2-MeO, X = Cl,
R = Me (VI); Y = 4-MeO, X = Cl, R = Me (VII).
2PhCH2Si(R)Cln + mBrMgC CH + BrMgC CMgBr
PhCH2(HC C)n 1RSiC CSiR(C CH)n 1CH2Ph,
R = Me, n = 2, m = 2; n = 3, m = 4.
Benzyl(diethynyl)(methyl)silane (VIII) and benzyl-
(diethynyl)(vinyl)silane (IX) were prepared by the
The yields, physicochemical constants, and ele-
mental analyses for the synthesized compounds are
given in Table 1. Their structure was proved by H,
13C, and 29Si NMR spectroscopy; these data are
presented in Table 2.
1
C6H5CH2(R)SiCl2 + 2BrMgC CH
C6H5CH2(R)Si(C CH)2 + 2MgClBr,
VIII, IX
In the IR spectra of all the synthesized compounds,
stretching vibrations of the monosubstituted acetylenic
R = Me (VIII), Vin (IX).
69

70
ZHILITSKAYA et al.
Table 1. Constants and elemental analyses of compounds I X
Found, %
H
Calculated, %
Y
Yield,
%
bp
(mm Hg)
d240
n2D0
Formula
(Comp. no.)
C
Si
C
H
Si
H (I)
H (II)
64
66
64
63
65
66
65
67
66
54
62(3)
106(6)
68(4)
95(9)
78(5)
95(1)
100(1)
92(2)
104(4)
106(2)
0.9265 1.5038 75.98
0.9287 1.5140 77.85
1.0055 1.4963 67.93
1.1012 1.5256 64.16
0.9295 1.5098 76.27
1.0060 1.5211 68.30
1.0069 1.5216 68.33
0.9605 1.5253 77.79
0.9800 1.5375 79.05
0.9877 1.5373 80.44
8.09
8.65
7.03
6.85
8.05
8.18
8.28
6.63
6.70
5.75
16.06
13.66
13.99
13.06
14.48
12.66
12.63
15.09
14.34
14.78
C11H14Si
C13H18Si
C11H13FSi
75.79 8.09 16.11
77.15 8.97 13.88
68.70 6.81 14.61
63.28 6.28 13.46
76.52 8.56 14.91
70.53 7.89 13.75
70.53 7.89 13.75
78.19 6.58 15.23
79.53 6.16 14.45
80.36 5.19 13.75
4-Fa (III)
4-Clb (IV)
4-Me (V)
2-MeO (VI)
4-MeO (VII)
H (VIII)
H (IX)
13ClSi
C11H
C12H16Si
C12H16OSi
C12H16OSi
C12H12Si
C13H12Si
C13H10Si
X
a
b
Found F, %: 9.12. Calculated F, %: 9.81.
Found Cl, %: 15.88. Calculated Cl, %: 16.98.
Table 2. 1H, 13C, 29Si NMR spectral parameters of compounds I X
1H NMR spectrum, , ppm (J, Hz) 13C NMR spectrum, C, ppm
29Si NMR
spectrum,
Si, ppm
Y
(Comp. no.)
MeSi
0.15
CH2
2.19
CH
C6H5
MeSi
1.84
CH2
C
CH
C6H5
H (I)
2.31
7.14 (o, p),
7.24 (m)
21.41 85.27 93.76 125.16 (p),
128.20 (o, m),
16.21
128.32 (o, m),
137.88 (i)
H (II)
0.96
(CH3),
0.4
(CH2)
0.12
2.20
2.84
2.41
2.13
2.23
2.12
2.36
2.38
2.51
2.34
2.35
2.37
7.07 (o),
7.12
(CH3),
4.04
(CH2)
1.53
22.35 86.69 95.17 127.37 (p),
128.11 (o, m),
16.11
16.38
16.23
16.48
16.16
16.51
.
(m),
7 18
7.30 (p)
138.32 (i)
4-Fa (III)
4-Cl (IV)
4-Me (V)
2-MeO (VI)
4-MeO (VII)
6.99 (o),
7.22 (m),
7.31 (p)
25.21 89.07 94.23 128.06 (p),
129.03 (m),
129.82 (o),
132.18 (i)
25.27 87.91 94.75 128.05 (p),
128.83 (m),
129.44 (o),
130.14 (i)
25.22 88.72 94.41 128.18 (p),
128.92 (o, m),
133.68,
135.15 (i)
19.51 89.12 93.56 109.85 (p),
125.64 (o, m),
0.32
0.11
0.11
0.12
7.23 (o),
7.27 (m),
7.21 (p)
2.52
2.37
1.99
2.35
6.94 (o),
6.99 (m),
2.29 (CH3)
7.04 (p),
6.75 (m),
3.74 (MeO)
129.76 (i),
54.79 (MeO)
24.56 88.72 94.31 113.77 (p),
129.13 (o, m),
6.67 (o),
6.98 (m),
3.73 (MeO)
130.32 (i),
55.13 (MeO)
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 1 2008

C- AND Si-SUBSTITUTED BENZYL(ETHYNYL)SILANES
71
Table 2. (Contd.)
1H NMR spectrum, , ppm (J, Hz)
13C NMR spectrum, C, ppm
CH2 CH C6H5
29Si NMR
spectrum,
Si, ppm
Y
(Comp. no.)
MeSi
CH2
2.31
CH
C6H5
MeSi
2.37
C
H (VIII)
Hb (IX)
X
0.25
2.44
7.16 (o),
7.12 (m),
7.19 (p)
25.19 84.72 95.86 125.08 (p),
128.32 (o, m),
128.65 (o, m),
136.69 (i)
25.87 82.84 96.87 125.09 (p),
128.32 (m),
128.79 (o),
136.50 (i)
25.00 81.40 96.85 125.53 (p),
128.33 (m),
38.61
45.57
64.82
2.41
2.48
7.11 (o),
(JH Si (JH Si 7.20 (m),
9.18)
2.41
4.4)
7.09 (p)
2.51
7.15 (o),
7.23 (m),
7.12 (p)
128.95 (o),
134.95 (i)
a 3
J
4
b 1
8.6, J
5.4 Hz.
H NMR, , ppm (J, Hz): 5.92, 5.96 (H ); 6.01, 6.07 (H ); 6.09, 6.13 (H ) (J
4.03, J 13.43,
gem cis
FCCH
FCCCH
13
A
B
C
J
20.15). C NMR,
, ppm: 129.49 (CH=), 132.64 (=CH ).
C 2
trans
bond give rise to a strong band with a maximum at
2030 cm . The vibration frequencies of the terminal
followed by the reaction with methyltrichloro- or
vinyltrichlorosilane, respectively. Benzyltrichloro-
silane was prepared by the reaction of benzyl chloride
with magnesium metal and tetrachlorosilane. Their
constants corresponded to published data [11, 12].
1
ethynyl groups in I X fall in the narrow range of
1
3250 3280 cm , independent of the number of
ethynyl groups in the molecule. The vinyl group in
1
IX absorbs at 1595, 3010, and 3060 cm . Benzene
Benzyl(ethynyl)dimethylsilane. The Grignard
reagent prepared from 2.4 g Mg and 12.7 g C6H5
CH2Cl in 50 ml of ether was added with stirring to a
solution of 10.2 g of dimethyl(ethynyl)fluorosilane in
25 ml of dry diethyl ether. The mixture was refluxed
for 1 h. The precipitate formed was filtered off and
washed with ether. The solvent was removed, and the
residue was distilled under a vacuum to afford 11.14 g
(64%) of compound I. Compounds II VII were
prepared similarly.
C=C absorption appears at 1585 1600 and 1495
1
1500 cm . The effect of substituent Y on the ethynyl
group in the compounds studied is weak.
Compounds I VII are suggested as models for
studying electronic interactions in the Y PhCH2Si
C=C moiety, and compounds VIII X can be em-
ployed as synthons in the design of new highly un-
saturated macrocyclic silahydrocarbons and dendri-
mers.
Benzyl(diethynyl)methylsilane (VIII). (Bromo-
magnesio)acetylene prepared from 4.8 g Mg, 21 g
EtBr, and acetylene in 100 ml of freshly distilled THF
was added with stirring to a solution of 20.4 g of
benzyl(methyl)dichlorosilane in 50 ml of dry diethyl
ether. The mixture was heated at 45 C for 30 min and
then decomposed with water and 5% HCl. The
aqueous layer was separated, extracted with ether
(3 30 ml), and the combined organic layer and ex-
tracts were dried over calcined CaCl2. The drying
agent was filtered off, washed with dry ether (2
30 ml), the solvents were distilled off under reduced
pressure, and the residue was distilled in a vacuum to
isolate 12.26 g (67%) of compound VIII.
EXPERIMENTAL
The NMR spectra were registered on a Bruker
DRX-400 (400 MHz) spectrometer for 15% solutions
in CDCl3 with HMDS as internal standard. The IR
spectra were obtained on a Specord IR75 spectrometer
in microlayer (0.194 mm).
All solvents used in the experiments were tho-
roughly dried.
The starting alkyl(ethynyl)fluorosilane and sub-
stituted benzyl halides were synthesized by earlier
described procedures [6 10]. Benzyldichloromethyl-
or benzyldichlorovinylsilanes were prepared by the
reaction of benzyl chloride with magnesium metal
Compounds IX and X were prepared similarly.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 1 2008

72
ZHILITSKAYA et al.
2004, vol. 74, no. 12, p. 2003.
ACKNOWLEDGMENTS
5. Arelavskaya, E.V., Vasneva, N.A., and Sladkov, A.M.,
Dokl. Akad. Nauk SSSR., 1977, vol. 234, no. 4,
p. 833.
This work was supported by the Grant Council
under the President of the Russian Federation (grant
no. NSh-4575-2006.3) and Design of New Carbon-
Silicon Composite Materials Integration Project 4.9.
6. Grosse, A.V. and Ipatieff, V.N., J. Org. Chem., 1943,
vol. 8, p. 440.
7. Kharasch, M.S., Zimmt, W.S., and Nudenberg, W.,
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 78 No. 1 2008