Ethynylisopropylgermanes and their trimethylsilyl derivatives

Article abstract of DOI:10.1023/A:1023450909838

The reaction of ethynylmagnesium bromide with chloroisopropylgermanes (i-Pr_4-nGeCl_n, n = 1-3) was used to prepare previously unknown ethynylisopropylgermanes i-Pr_4-nGe(C≡CH)_n (n = 1-3). The reaction of Me_3<

Full text of DOI:10.1023/A:1023450909838

Russian Journal of General Chemistry, Vol. 72, No. 12, 2002, pp. 1901 1903. Translated from Zhurnal Obshchei Khimii, Vol. 72, No. 12, 2002,
pp. 2009 2011.
Original Russian Text Copyright
2002 by O. Yarosh, N. Yarosh, Albanov, Voronkov.
Ethynylisopropylgermanes and Their Trimethylsilyl Derivatives
O. G. Yarosh, N. O. Yarosh, A. I. Albanov, and M. G. Voronkov
Favorskii Irkutsk Institute of Chemistry, Siberian Division, Russian Academy of Sciences, Irkutsk, Russia
Received February 19, 2001
Abstract The reaction of ethynylmagnesium bromide with chloroisopropylgermanes (i-Pr4 nGeCln, n =
1 3) was used to prepare previously unknown ethynylisopropylgermanes i-Pr4 nGe(C CH)n (n = 1 3). The
reaction of Me3SiC CMgBr with i-PrGeCl3 afforded i-Pr(Me3SiC C)3 nGeCln (n = 1, 2). The reaction of the
monochloride with BrMdC CH gave i-Pr(HC C)2GeC CSiMe3, while with the dichloride, i-Pr(HC C)
Ge(C SiMe3)2 formed. The latter compounds were obtained by independent synthesis from i-PrGe(C CH)3,
EtMgBr, and ClSiMe3. The reaction of (bromomagnesioethynyl)triisopropylgermane with Me3SiCl gave
i-Pr3GeC SiMe3.
Organogermanium compounds containing an
ethynyl group on the germanium atom are poorly ex-
plored. The only known compounds are R4 n
Ge(C CH)n (R = Me, n = 1 4 [1, 2]; R = Et, n = 1, 2
[3, 4]; R = H, n = 1 [5]; R = n-Bu, n = 1, 2 [4, 6]; R =
Cl, n = 1 [3]).
i-PrGeCl3 + BrMgC CSiMe3
i-Pr(Me3SiC C)GeCl2 + i-Pr(Me3SiC C)2GeCl. (2)
IV
V
The reactions of compounds IV and V with ethynyl-
magnesium bromide lead to the corresponding ethynyl
derivatives.
Continuing research into acetylenic germanium
compounds [7], we turned to the reaction of isopropyl-
germanes i-Pr4 nGeCln (n = 1 3) with ethynyl-
magnesium bromide in THF with the purpose of pre-
paring ethynylisopropylgermanes. It was expected that
the sterically congested isopropyl groups at the ger-
manium atom would specifically affect the reactivity
of the starting compounds and the final products.
Therewith, we prepared formerly unknown ethynyl-
germanes of the above series with R = i-Pr.
IV + 2BrMgC CH
V + BrMgC CH
i-Pr(HC C)2GeC CSiMe3, (3)
VI
i-Pr(HC C)Ge(C CSiMe3)2. (4)
VII
Compounds VI and VII were also obtained by
independent synthesis from triethynylisopropylger-
mane, ethylmagnesium bromide, and chlorotrimethyl-
silane.
i-Pr4 nGeCln + nBrMgC CH
i-Pr4 nGe(C CH)n, (1)
I III
i-PrGe(C CH)3 + EtMgBr + ClSiMe3
VI + VII. (5)
n = 3 (I), 2 (II), 1 (III).
Triisopropylgermane under these conditions forms
triisopropyl(trimethylsilylethynyl)germane.
The starting chloroisopropylgermanes were pre-
pared by the reactions of isopropylmagnesium bromide
with GeCl4 at 2:1 and 2.5:1 molar ratios, respec-
tively. In the first case, i-PrGeCl3, i-Pr2GeCl2,
and i-Pr3GeCl were formed in a 9:5:3 ratio, and in
the second, in a 1:1:1 ratio. Up to now these com-
pounds have been prepared by a multistage procedure
in low yields [8 10].
i-PrGeC CH + EtMgB + ClSiMe3
i-Pr3GeC CSiMe3.
(6)
VIII
The resulting data show that even three isopropyl
groups on the germanium atom only slightly affect
the reactivity of the Ge Cl bond.
The reaction of trichloroisopropylgermane with
trimethylsilylethinylmagnesium bromide (1:1 molar
ratio) occurs in a similar way and involves substitu-
tion of one or two chlorine atoms by trimethylsilyl-
ethynyl groups.
The physicochemical constants and elemental
analyses of the obtained compounds are listed in
1
Table 1. Their structure was proved by H, 13C, and
29Si NMR spectroscopy (Table 2). Isopropylgermanes
1070-3632/02/7212-1901$27.00 2002 MAIK Nauka/Interperiodica

1902
YAROSH et al.
Table 1. Physicochemical constants and elemental analyses of compounds I VIII
Found, %
Calculated, %
H
Comp. Yield,
bp,
(p, mm)
C
d240
n2D0
Formula
no.
%
C
H
Ge
C
Ge
I
II
III
IV
V
77
90
85
42
37
72
71
82
70 (25)
75 (20)
75 (10)
95 (2)
123 (2)
89 (2)
1.0752 1.4612 56.42
1.0363 1.4615 57.20
0.9659 1.4620 58.52
1.1870 1.4728
1.0894 1.4770
1.0069 1.4656 54.60
5.41
7.99
9.73
38.12
33.50
31.97
C9H10Ge
C10H16Ge
C11H22Ge
C8H16Cl2GeSi
C13H25ClGeSi2
C12H18GeSi
C15H26GeSi2
C14H30GeSi
56.66
57.51
58.23
5.28
7.72
9.77
38.05
34.76
32.00
VIa
VIIb
VIIIc
6.90
7.79
27.56
20.89
54.81
53.75
6.89
7.82
27.83
21.66
3
75 (10 ) 1.0073 1.4730 53.02
113 (2)
0.9521 1.4640 56.07 10.14 24.08
56.22 10.11 24.27
a
b
c
Found Si, %:10.39. Calculated Si, %: 10.68. Found Si, %: 15.65. Calculated Si, %: 16.7. Found Si, % 9.32. Calculated Si, %:
9.39.
Table 2. 1H, 13C, and 29Si NMR data of ethynylgermanes
Comp.
no.
1H NMR spectrum, , ppm
13C NMR spectrum, C, ppm
29Si NMR
spectrum,
Si, ppm
CH3CGe CCHGe HC C CH3Si CH3CGe CCHGe HC C
GeC
CSi
CH3Si
I
II
III
VI
1.21
1.19
1.16
1.21
1.57
1.30
1.38
1.53
2.45
2.34
2.24
2.41
19.03
18.57
19.52
19.32
17.21
16.30
14.58
17.38
94.33
94.40
93.82
93.87
80.09
82.56
86.82
80.89, 115.88
101.89
81.53, 115.89
102.83
106.23
0.20
0.14
0.17
0.30
0.27
0.11
17.60
17.79
18.90
VII
1.16
1.17
1.34
1.25
2.33
19.47
18.90
17.45
16.75
93.53
VIII
115.14
I III we additionally studied by IR spectroscopy. The
ter and a 5% HCl solution. After usual workup and
drying over calcined CaCl2, the solvents were re-
moved in a water-jet-pump vacuum, and the residue
was distilled in a vacuum to give 7.26 g (75%) of
compound I.
ethynyl group gives strong stretching absorption
1
bands at 2020 2030 ( C C) and 3280 cm
( CH).
The i-Pr Ge bonds give stretching vibration bands at
1
1360 1365 and 1460 1465 cm . Asymmetric vibra-
tion bands of the i-Pr Ge and Ge C bonds are ob-
served at 560 570 and 490 cm , respectively.
Compounds II and III were prepared in a similar
way, and compounds VI and VII, by reactions (3)
and (4).
1
EXPERIMENTAL
1-(Dichloroisopropylgermyl)-2-(trimethylsilyl)-
ethyne (IV) and chloroisopropylbis(trimethylsilyl-
ethynyl)germane (V). To a solution of 11.1 g of tri-
chloroisopropylgermane in 50 ml of ether, the solu-
tion of Me3SiC CMgBr, prepared from 1.21 g of
magnesium, 5.45 g of EtBr, and 5.0 g of Me3SiC CH
in 50 ml of THF, was added dropwise with stirring.
Further treatment of the reaction mixture was carried
out as described above. The yields of compounds IV
and V were 6.18 g (42.2%) and 5.39 g (36.8%),
respectively.
The IR spectra were obtained on a Specord IR-75
spectrometer in thin layer. The NMR spectra were
registered on a Bruker DRX-400 spectrometer for
15% solutions in CDCl3 against internal TMS.
Ethynyltriisopropylgermane. To a solution of
11.1 g of trichloroisopropylgermane in 50 ml of ether,
the solution of ethynylmagnesium bromide prepared
from 3.65 g of Mg, 16.5 g of EtBr, and acetylene in
150 ml of THF, was added dropwise with stirring. The
mixture was stirred for 1 h and then treated with wa-
Compound VIII were prepared in a similar way.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 12 2002

ETHYNYLISOPROPYLGERMANES AND THEIR TRIMETHYLSILYL DERIVATIVES
1903
ACKNOWLEDGMENTS
pulo, T.P., and Vannikov, A.V., Zh. Obshch. Khim.,
1973, vol. 43, no. 12, pp. 2701 2703.
The work was financially supported by the Russian
Foundation for Basic Research (project no. 00-15-
97395).
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vol. 44, no. 7, pp. 2602 2604.
6. Lesbre, M. and Satge, J., C. R. Acad. Sci. Fr., 1960,
vol. 250, no. 12, pp. 2220 2222.
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RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 72 No. 12 2002