Reaction of tetrachlorogermane with thienyl- and phenylchlorosilanes in presence of aluminum chloride. Synthesis of thienylchlorogermanes

Article abstract of DOI:10.1134/S1070363214020212

Reaction of tetrachlorogermane with 2-thienylchlorosilane and methyl(2-thienyl)dichlorosilane in presence of AlCl₃ is studied. It was shown that in the reaction with 2-thienyltrichlorosilane 2-thienyltrichlorogermane mainly formed, while in the reactions with methyl(2-thienyl)dichlorosiulane aromatic germaniumcontaining compounds like 2-thienyltrichlorogermane and di(2-thienyl)dichlorogermane were obtained. Quantum-chemical calculations showed that the reaction of chlorine atoms exchange in GeCl₄ with aromatic moiety formed from arylchlorosilanes in the presence of AlCl₃ proceeds through a four-membered activated complex.

Full text of DOI:10.1134/S1070363214020212

ISSN 1070-3632, Russian Journal of General Chemistry, 2014, Vol. 84, No. 2, pp. 280–284. © Pleiades Publishing, Ltd., 2014.
Original Russian Text © V.G. Lakhtin, M.I. Vorob’eva, E.G. Gordeev, V.N. Ushakov, A.D. Kirillin, V.G. Bykovchenko, N.A. Golub, E.A. Chernyshev, 2014,
published in Zhurnal Obshchei Khimii, 2014, Vol. 84, No. 2, pp. 288–292.
Reaction of Tetrachlorogermane with Thienyl-
and Phenylchlorosilanes in Presence of Aluminum Chloride.
Synthesis of Thienylchlorogermanes
V. G. Lakhtina, M. I. Vorob’evaa, E. G. Gordeevb, V. N. Ushakovc,
A. D. Kirillinb, V. G. Bykovchenkoa, N. A. Golubb, and E. A. Chernysheva
a State Scientific and Research Institute of Chemistry and Technology of Organoelemental Compounds,
sh. Entuziastov 38, Moscow, 105118 Russia
e-mail: eos2004@inbox.ru
b Lomonosov Moscow State University of Fine Chemical Technologies, Moscow, Russia
c Topchiev Institute of Petrochemical Synthesis, Russian Academy of Sciences, Moscow, Russia
Received March 21, 2013
Abstract―Reaction of tetrachlorogermane with 2-thienylchlorosilane and methyl(2-thienyl)dichlorosilane in
presence of AlCl3 is studied. It was shown that in the reaction with 2-thienyltrichlorosilane 2-thienyltrichloro-
germane mainly formed, while in the reactions with methyl(2-thienyl)dichlorosiulane aromatic germanium-
containing compounds like 2-thienyltrichlorogermane and di(2-thienyl)dichlorogermane were obtained.
Quantum-chemical calculations showed that the reaction of chlorine atoms exchange in GeCl4 with aromatic
moiety formed from arylchlorosilanes in the presence of AlCl3 proceeds through a four-membered activated
complex.
DOI: 10.1134/S1070363214020212
One of the most simple and available methods of
preparation of arylchlorogermanes is the liquid phase
reaction of GeCl4 with arylchlorosilanes in the
presence of aluminum chloride. In this way various
phenylchlorogermanes like C6H5GeCl3, ClC6H4GeCl3,
(C6H5)2GeCl2, etc. are formed [1–6]. Research per-
formed resulted in establishing some rules of the
synthesis. As shown in [2] the highest yields of phenyl-
trichlorogermanes were obtained while using methyl-
phenyldichlorosilane and not phenyltrichlorosilane.
Note that in reactions with MePhSiCl2 no organo-
germanium compounds with methyl groups were
found. It was shown [3–6] that the concentration of
AlCl3 plays an important role in the formation of
reaction products. At the concentration of AlCl3 of 3–
5% the formation of PhGeCl3, Ph2GeCl2 and Ph3GeCl
takes place, while at the increase in its concentration to
30–40% phenyltrichlorogermane becomes the main
product.
use this method for the preparation of various
thienylchlorogermanes exhibiting biological activity.
Nowadays the information on the mechanism of the
reaction of tetrachlorogermane with arylchlorosilanes
in the presence of AlCl3 is scarce. Therefore we also
carried out quantum-chemical calculations of the
reactions taking place in this process.
In this work 2-thienyltrichlorosilane I and di(2-thi-
enyl)dichlorosilane II were used as starting substances.
First of all we have studied the reaction of tetrachloro-
germane with compound I. 2-Thienyltrichlorogermane
III was the main reaction product.
AlCl3
ThSiCl3 + GeCl4
ThGeCl3 + SiCl4,
(1)
I
III
Th = 2-thienyl.
Compound III formed in 25–32% (Table 1). At the
increase in AlCl3 concentration the yield of 2-
thienyltrichlorogermane decreased evidently first of all
because of its decomposition. This suggestion is con-
firmed by the fact that the nearest analog of compound
No data concerning the synthesis of another
arylchlorogermanes in this way has been reported up
till now. In the present study we made an attempt to
280

REACTION OF TETRACHLOROGERMANE WITH THIENYL- AND PHENYLCHLOROSILANES
281
Table 1. Reaction conditions and yields of the products in the reaction of GeCl4 with 2-thienyltrichlorosilane I in the
a
presence of AlCl3
AlCl3 amount, mol %
Reaction time, h
Yield of compound III, %b
Conversion of starting compound I, %
10
20
30
40
8
6
4
4
32
30
28
25
68
74
95
100
a Reaction temperature 120°C, molar ratio of reagent I to GeCl4 1 : 1. b With respect to starting GeCl4.
III, phenyltrichlorogermane, decomposes noticeably in
the presence of high concentrations of AlCl3. Hence,
while heating PhGeCl3 for 4 h at 120°C in the presence
of 5 and 20 mol % of AlCl3 its decomposition reached
0.4 and 13.2% respectively [3].
In Table 2 yields of compounds III and IV at
varying reaction temperature from 80 to 120°C, the
reaction time from 4 to 10 h, and aluminum chloride
concentration from 5 to 30 mol % are presented.
Yields of compound III in reaction (2) are
significantly higher than in reaction (1). They vary in
the range of 38–62%. Temperature within the studied
limits slightly affects the yield of compound III. Its
yield most strongly depends on the concentration of
aluminum chloride. At the AlCl3 concentration 5 mol %
yield of compound III is 38–41%, and at the increase
in AlCl3 content to 30 mol % the yield of the target
substance reaches 56–62% (see Table 2).
The reaction of GeCl4 with another thienyl
compound, methyl(2-thienyl)dichlorosilane II, was
studied more thoroughly because the yields of organo-
germanium compounds in this case were higher those
mentioned above. In the reaction of compound II with
tetrachlorogermane two organogermanium compounds,
2-thienyltrichlorogermane III and di(2-thienyl)di-
chlorogermane IV are formed. It is evident that mono-
substituted compound III is formed according to the
reaction (2) at the exchange of one chlorine atom in
tetrachlorogermane with 2-thienyl moiety while com-
pound IV is the result of substitution of two chlorine
atoms with 2-thienyl moieties.
The yield of compound IV also significantly
depends on the concentration of AlCl3, and not on the
reaction temperature. Maximum yield (39–44%) of this
substance was obtained in the presence of 5 mol %, and
the lowest one (4–6%) is observed in the presence of
30 mol % of AlCl3 (Table 2).
AlCl3
MeThSiCl2 + GeCl4
ThGeCl3 + MeSiCl3, (2)
II
III
Table 2. Reaction conditions and yields of the products in
the reaction of GeCl4 with methyl(2-thienyl)dichlorosilane
II in the presence of AlCl3
AlCl3
II + III
Th2GeCl2 + MeSiCl3,
(3)
IV
Yield, %b
AlCl3 amount,
Т, оС
Reaction time, h
Th = 2-thienyl.
mol %
III
IV
5
5
80
80
4
10
4
38
41
40
40
38
42
54
49
45
62
57
56
44
39
34
29
30
27
14
8
It may be suggested that the exchange of the second
chlorine atom takes place in the obtained mono-
substituted compound III. The direct experiment of the
reaction between compounds II and III confirmed the
possibility of such reaction. Hence, in the presence of
10% of AlCl3 at 110–120°C compound IV is formed in
40% yield according to reaction (3) in the course of
4 h.
5
120
80
10
10
10
20
20
20
30
30
30
4
80
10
4
120
80
4
100
120
80
4
4
10
6
Note that in the reactions (2) and (3) the exchange
of chlorine atom in tetrachlorogermane and the
compound III occurs only with the thienyl moiety. No
exchange of methyl group with chlorine either in
GeCl4 or in the compound III was observed.
4
100
120
4
4
4
4
a
b
Molar ratio of reagent II and GeCl4 1.5 : 1. With respect to
starting GeCl4.
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LAKHTIN et al.
Comparison of experimental data presented in
to reactions (1)–(5). For example, the exchange
between chlorine in tetrachlorogermane and organic
moiety, forming from alkylarylchlorosilanes is
observed only for aromatic substituents (phenyl or
thienyl) but not the alkyl (methyl) ones.
Tables 1, 2 shows that for preparative needs compound
III must be obtained by the reaction of tetrachloro-
germane with methyl(2-thienyl)dichlorosilane and not
with (2-thienyl)trichlorosilane.
The availability of compound III permitted the
preparation of organogermanium compound with two
different aryl substituents according to the following
reaction.
For better understanding of mechanism of tetra-
chlorogermane reaction with arylchlorosilanes in the
presence of AlCl3 we have carried out quantum
chemical calculations for compounds with phenyl
substituents which are easier to calculate. By density
functional theory [8] using the hybrid M062X meta-
functional [9] and split valence basis set 6-31G(d,p)
thermodynamic parameters of reaction (4) of substi-
tuent exchange between phenyltrichlorosilane and tetra-
chlorogermane were calculated. It turned out that this
reaction was exothermic with the reaction enthalpy
equal to –8.0 kcal/mol and Gibbs energy –7.3 kcal/mol.
ThGeCl3 + PhSiCl3 → ThPhGeCl2 + SiCl4.
By this procedure (2-thienyl)phenyldichloro-
germane was obtained in 40% yield. Detailed descrip-
tion of this synthesis is given in Experimental.
Note that the formation of phenylchlorogermanes
proceeds according to the same type of reactions (1)–
(3) [1–6].
AlCl3
For evaluation of potential barrier of reaction (4)
and the effect of catalyst on its value we have found
transition states of this process without the participa-
tion of aluminum chloride [reaction (6)] as well as
with its participation in the formation of transition state
[reaction (7)]. Non-catalytic process has the potential
barrier ΔE# = 39.5 kcal/mol while coordination with
aluminum chloride leads to decrease in this barrier to
ΔE# = 34.8 kcal/mol.
PhSiCl3 + GeCl4
PhGeCl3 + SiCl4,
(4)
(5)
AlCl3
MePhSiCl2 + GeCl4
PhGeCl3 + Ph2GeCl2
+ MeSiCl3.
There is much in common between the syntheses of
thienyl- and phenylchlorogermanes proceeding according
Ph
GeCl3
Cl3Si
PhSiCl3 + GeCl4
SiCl4 + PhGeCl3
(6)
(7)
Cl
TS1
Ph
GeCl3
Cl3Si
PhSiCl3 + GeCl4 + 1/2Al2Cl6
SiCl4 + PhGeCl3 + 1/2Al2Cl6
Cl
AlCl3
TS2
Transition states (see the figure) have four-
membered structure and possess one imaginary
frequency in the vibration spectrum corresponding to
the motion of atoms along the reaction coordinate. In
the transition states interatomic distances are shown in Å.
complex TS1 which then decomposes to starting
substances. But reaction (6) is useful for considering
specific features of formation of activated complex
TS2 in the presence of aluminum chloride.
From the comparison of the transition states TS1
and TS2 if follows that coordination with AlCl3 leads
to the increase in the interatomic distance from 2.625
to 3.047 Å between the migrating chlorine atom and
Note that reaction (6) without the catalyst
practically does not go to completion. It evidently
finishes on the stage of the formation of activated
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REACTION OF TETRACHLOROGERMANE WITH THIENYL- AND PHENYLCHLOROSILANES
(a) (b)
283
Molecular structure of the transition states of reaction (4) without (a) and with the catalyst(b) (interatomic distances are given in Å).
Cl
Si
the germanium atom. The bond length between the
phenyl group and the silicon atom increases from
2.029 to 2.305 Å while the bond between the phenyl
group and germanium atom decreases from 2.020 to
1.965 Å. It evidently creates good conditions for
migration of phenyl group from silicon to germanium,
and of chlorine atom from germanium to silicon.
Cl
Ph
Cl
Cl
Cl
Cl
Cl
Ph
Cl
Cl
Cl
Cl
Si
Al
Ge
Cl
Cl
Cl
Ge
Cl
Al
Cl
Cl
Cl
Cl
Cl
TS4
TS3
The correspondence of transition states to the
reaction of phenyl substituent transfer is confirmed by
the calculation of intrinsic reaction coordinate of the
(IRC calculations).
Hence, proceeding of the exchange reaction (4)
through the formation of four-membered transition
complex TS2 is the most probable.
Six-membered activated complex TS3 that we
suggested before quantum-chemical studies and fairly
intricate activated complex TS4 assumed in [5, 6] for
reactions catalyzed with AlCl3 were not localized
within the frames of chosen M062X/6-31G(d,p)
approximation. In particular, TS3 state during the
optimization transforms to TS2.
EXPERIMENTAL
Starting substances and reaction products were
analyzed by GLC on an LKhM-80 chromatograph
equipped with a katharometer, helium carrier gas,
30 mL/min. Analysis was carried out on a 0.3×200 cm
stainless steel column filled with Chromaton N-AW-
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284
LAKHTIN et al.
DMCS solid carrier with the particle size 0.25–
0.31 mm, stationary phase SE-30 silicon elastomer
(5% mass), ramp from 30 to 250°C at a rate 12°C/min.
REFERENCES
1. Chernyshev, E.A., Kurek, M.E., and Polivanov, A.N.,
USSR Authors Certificate no. 316663, Bull. Izobr.,
1971, vol. 30.
2. Motsarev, G.V., Chernyshev, E.A., Rozenberg, V.R.,
Inshakova, V.T., and Zetkin, V.I., Zh. Obshch. Khim.,
1983, vol. 53, no. 5, p. 1111.
3. Lakhtin, V.G., Kurakaeva, N.A., Mid’ko, A.A.,
Pyatova, Yu.I., and Chernyshev, E.A., Dep. VINITI,
Moscow, 2003, no. 1850-B2003.
4. Zhun’, V.I., Sbitneva, I.V., and Chernyshev, E.A., Russ.
J. Gen. Chem., 2005, vol. 75, no. 6, p. 867.
1H NMR spectra were registered on a Bruker AM-
360 (360 MHz) Fourier spectrometer. Liquid sub-
stances were analyzed as 15–30% solutions in CDCl3.
Chemical shifts are measured with respect to TMS.
Reaction of 2-thienyltrichlorosilane I with tetra-
chlorogermane in the presence of AlCl3. The mixture
of 19.6 g of 2-thienyltrichlorosilane, 19.3 g of ger-
manium tetrachloride, and 2.67 g of AlCl3 was stirred
for 8 h at 120°C and then cooled. The mixture obtained
was treated with 3.10 g of POCl3, and the obtained
complex was filtered off. The filtrate was distilled in a
vacuum to give 7.55 g of 2-thienyltrichlorogermane
5. Zhun’, V.I., Sbitneva, I.V., and Chernyshev, E.A.,
Abstracts of Papers, 10th All-Russian Conf. “Organo-
silicon Compounds” Dedicated to 100th Anniversary of
Academician K.A. Andrianov, Moscow, 2005, p. 22.
6. Sbitneva, I.V., Candidate Sci. (Chem.) Dissertation,
III, bp 73°C (3–4 mm Hg), nD20 1.5650. H NMR
1
Moscow, 2006.
spectrum, δ, ppm: 7.60 d (H5, 3JHH 4.7 Hz ), 7.47 d (H3,
7. Lukevits, E.Ya, Gar, T.K., Ignatovich, L.M., and
Mironov, V.F., Biologicheskaya aktivnost’ soedinenii
germaniya (Biological Activity of Germanium Com-
pounds), Riga: Zinatne, 1990, p. 191.
3
3JHH 3.2 Hz), 7.11 d.d (H4, 3JHH 4.7 Hz, JHH 3.2 Hz).
Yield of compound III basing on starting
tetrachlorogermane 32%.
8. Koch, W. and Holthausen, M.C., A Chemist’s Guide to
Density Functional Theory, Weinheim: Wiley-VCH
Verlag GmbH, 2001, p. 344.
Reaction of methyl(2-thienyl)dichlorosilane II
with tetrachlorogermane in the presence of AlCl3.
The mixture of 23.6 g of methyl(2-thienyl)di-
chlorosilane, 17.2 g of GeCl4, and 2.91 g of AlCl3 was
stirred at 80°C for 4 h and then cooled. Resulting
mixture was treated with 3.37 g of POCl3 and filtered.
The filtrate was distilled in a vacuum to give 8.39 g
(40%) of 2-thienyltrichlorogermane III and 7.20 g
(29%) of di(2-thienyl)dichlorogermane of bp 165–167°C
(1–2 mm Hg), nD20 1.6182. 1H NMR spectrum, δ, ppm:
7.50 d (H5, 3JHH 4.6 Hz); 7.43 d (H3, 3JHH 3.4 Hz); 7.05
d.d (H4, 3JHH 4.6 Hz, 3.4 Hz).
9. Zgao, Y. and Truhlar, D.G., Theor. Chem. Account,
2008, vol. 120, no. 1, p. 215.
10. Frisch M.J., Trucks, G.W., Schlegel, H.B., Scuseria, G.E.,
Robb, M.A., Cheeseman, J.R., Scalmani, G., Barone, V.,
Mennucci, B., Petersson, G.A., Nakatsuji, H., Caricato, M.,
Li, X., Hratchian, H.P., Izmaylov, A.F., Bloino, J.,
Zheng, G., Sonnenberg, J.L., Hada, M., Ehara, M.,
Toyota, K., Fukuda, F., Hasagawa, J., Ishida, M.,
Nakajima, T., Honda, Y., Kitao, O., Nakai, H., Vreven, T.,
Montgomery, J.A. Jr., Peralta, J.E., Ogliaro, F.,
Bearpark, M., Heyd, J.J., Brothers, E., Kudin, K.N.,
Staroverov, V.N., Kobayashi, R., Normand, J.,
Raghavachari, K., Pendrell, A., Burant, J.C., Iyengar, S.S.,
Tomasi, J., Cossi, M., Rega, N., Millam, J.M., Klene, M.,
Knox, J.E., Cross, J.B., Bakken, V., Adamo, C.,
Jaramillo, J., Gomperts, R., Stratmann, R.E., Yazyev, O.,
Austin, A.J., Cammi, R., Pomelli, C., Ochterski, J.W.,
Martin, R.L., Morokuma, K., Zakrzewski, V.G., Voth, G.A.,
Salvador, P., Dannenberg, J.J., Dapprich, S., Daniels, A.D.,
Ferkas, O., Foresman, J.B., Ortiz, J.V., Cioslowski, J.,
and Fox, D.J., Gaussian 09, Revision A.02, Wallingford
CT, Gaussian Inc., 2009.
Reaction of methylphenyldichlorosilane with 2-
thienyltrichlorogermane in the presence of AlCl3.
The mixture of 17.2 g of methylphenyldichlorosilane,
23.6 g of 2-thienyltrichlorogermane, and 2.67 g of
AlCl3 was stirred at 60°C for 6 h and then cooled. The
mixture obtained was treated with 3.07 g of POCl3 and
filtered. The filtrate was distilled in a vacuum to give
8.48 g of (2-thienyl)phenyldichlorogermane V, bp
152°C (2–3 mm Hg), nD20 1.6075. H NMR spectrum,
1
δ, ppm: 7.44, 7.36, 7.00.
RUSSIAN JOURNAL OF GENERAL CHEMISTRY Vol. 84 No. 2 2014