Reactions of dodecamethylcyclohexasilane and polydimethylsilane with metal chlorides

Article abstract of DOI:10.1016/S0022-328X(03)00463-7

The reactions of dodecamethylcyclohexasilane and high-molecular-weight polydimethylsilane with chlorides of I, II, IV-VI and VIII Group metals at high temperature in the absence of a solvent were studied. The interaction of (Me₂Si)₆ with metal chlorides proceeds with the cleavage of Si-Si and Si-C bonds with the formation of chloro derivatives of linear and cyclic permethyloligosilanes. The reactions of polydimethylsilane with metal chlorides afford mixtures of α,ω-dichlorooligosilanes, Cl(Me₂Si)_nCl (n=2-9). The influence of the reaction conditions (temperature, reaction time and the reagent ratio) on the composition and yields of the reaction products was examined.

Full text of DOI:10.1016/S0022-328X(03)00463-7

Journal of Organometallic Chemistry 679 (2003) 17ꢀ23
/
www.elsevier.com/locate/jorganchem
Reactions of dodecamethylcyclohexasilane and polydimethylsilane
with metal chlorides
A.I. Chernyavskii *, D.Yu. Larkin, N.A. Chernyavskaya
A.N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Vavilov Street 28, 119991 Moscow, Russia
Received 10 March 2003; received in revised form 7 May 2003; accepted 7 May 2003
Abstract
The reactions of dodecamethylcyclohexasilane and high-molecular-weight polydimethylsilane with chlorides of I, II, IVꢀ
VIII Group metals at high temperature in the absence of a solvent were studied. The interaction of (Me2Si)6 with metal chlorides
proceeds with the cleavage of SiꢀSi and SiꢀC bonds with the formation of chloro derivatives of linear and cyclic
permethyloligosilanes. The reactions of polydimethylsilane with metal chlorides afford mixtures of a,v-dichlorooligosilanes,
Cl(Me2Si)nCl (nꢁ2ꢀ9). The influence of the reaction conditions (temperature, reaction time and the reagent ratio) on the
/VI and
/
/
/
/
composition and yields of the reaction products was examined.
# 2003 Elsevier B.V. All rights reserved.
Keywords: Dodecamethylcyclohexasilane; Polydimethylsilane; Metal chlorides; Chloro derivatives of oligosilanes
1. Introduction
treatment of dodecamethylcyclohexasilane (Me2Si)6 (2)
with chlorinating agents, such as Cl2 [23,24], SOCl2,
SCl2 [25], PCl5 [26] and gallium(III), tin(IV), titaniu-
m(IV) chlorides [27].
Dichloro-substituted linear and cyclic permethyloli-
gosilanes are convenient starting compounds for the
synthesis of polymers or copolymers containing oligosi-
Chloro derivatives of cyclohexasilane 2 with the
general formula ClmSi6Me12ꢂm (2a
/
c with mꢁ
/
1ꢀ3,
/
lane fragments in a backbone [1ꢀ15]. a,v-Dichloroper-
/
ꢀ
respectively) are prepared by chlorodemethylation of
cyclosilane 2 on treatment with dry HCl in the presence
of catalytic amounts of AlCl3 (chlorocyclosilane 2a) [28]
or by the reaction of cyclosilane 2 with SbCl5 (mono-
methyloligosilanes Cl(Me2Si)nCl (1) have been prepared
previously by chlorodemethylation of hexamethyldisi-
lane Me(SiMe2)2Me (dichlorodisilane 1a) and octa-
methyltrisilane Me(SiMe2)3Me (dichlorotrisilane 1b)
chloro-, dichloro- and trichlorocyclosilanes 2aꢀ
/c)
[16ꢀ19], chlorodephenylation of 1,4-diphenylocta-
/
[2,27,29ꢀ31].
/
methyltetrasilane Ph(SiMe2)4Ph (dichlorotetrasilane 1c)
[20] and 1,5-diphenyldecamethylpentasilane Ph(Si-
Me2)5Ph (dichloropentasilane 1d) [21], reductive cou-
pling of Me2SiCl2 with SmI2 (a mixture of
High-molecular-weight polydimethylsilane (3) is a
convenient starting compound for the synthesis of
dichlorooligosilanes 1. However, the data of the synth-
esis of dichlorooligosilanes 1 by the reactions of poly-
dichlorosilanes 1a c) [22].
The method used most widely to prepare chloro-
substituted linear and cyclic oligosilanes is the reaction
/
ꢀ
silane
3
with chlorinating agents are scarce.
Dichlorodisilane 1a was prepared in 43% yield by
passing chlorine through a suspension of polysilane 3
of permethylcyclosilanes (Me2Si)n (nꢁ/5 or 6) with
in CCl4 at ꢂ20 8C [23]. A mixture of dichlorooligosi-
/
different chlorinating agents. Thus dichlorooligosilanes
lanes 1 was obtained by the reaction of polysilane 3 with
SnCl4 at high temperature [27]. However, the data on
the compositions of the reaction products and the ratios
between these products are lacking.
In the present study, with the aim of synthesizing
dichlorooligosilanes 1 and chloro derivatives of cyclo-
1a
/
c and dichlorohexasilane (1e) are prepared by
ꢀ
* Corresponding author. Tel.: ꢃ
/
7-95-135-9228; fax: ꢃ7-95-135-
/
5085.
E-mail address: victor@interface.ru (A.I. Chernyavskii).
0022-328X/03/$ - see front matter # 2003 Elsevier B.V. All rights reserved.
doi:10.1016/S0022-328X(03)00463-7

18
A.I. Chernyavskii et al. / Journal of Organometallic Chemistry 679 (2003) 17ꢀ23
/
hexasilane 2, we examined the reactions of cyclohex-
asilane 2 and polysilane 3 with chlorides of I, II, IVꢀVI
and VIII Group metals in variable oxidation states
(MClk) and investigated the influence of the reaction
conditions on the conversion of cyclohexasilane 2 and
polysilane 3, the compositions of the reaction products
and their yields.
(80ꢀ
chlorides studied with cyclosilane 2, the intensity of
cleavage of the SiꢀMe bonds in the initial ring increases,
which results in markedly higher proportions of chloro-
substituted cyclosilanes in the products. Indeed, ZrCl4
and WCl6 react with cyclosilane 2 with the predominant
/
100%). In the reactions of the rest of metal
/
/
formation of chloro-substituted cyclosilanes 2a
chlorinated cyclosilanes ClmSi6Me12ꢂm (2d, m ꢀ
also formed. CrCl3 and FeCl3 proved to be the poorest
chlorinating agents for cyclosilane 2: the degree of
/
c; poly-
ꢀ
/3) are
2. Results and discussion
conversion of 2 was 520%; however, even in those
/
cases where the conversion of cyclosilane 2 in the
reactions with metal chlorides was rather high, the yield
2.1. Reactions of cyclohexasilane 2 with metal chlorides
of linear dichlorooligosilanes 1a
55%.
Previously, it was shown [27] that the reaction of
SbCl5 with cyclosilane 2 in the presence of a solvent
(CH2Cl2, CHCl3, CCl4) proceeds selectively with clea-
/
c, e did not exceed
Previously [27], it was shown that the reaction of
cyclosilane 2 with SnCl4 in CH2Cl2 gives not only
dichlorohexasilane 1e as the major product but also its
ꢀ
lower homologues 1a
/
c formed upon cleavage of the
ꢀ
Si bond cleavage in cyclosilane 2 and
Siꢀ
/
Si bond in oligomer 1e. Later [9], it was found that
vage of only Siꢀ
/
Me bonds in the initial cyclosilane 2, the
the reaction of cyclosilane 2 with SnCl4 is accompanied
SiꢀSi bonds remaining intact. When reproducing the
/
by not only Siꢀ
/
procedure, we obtained almost analogous results (see
Table 1, entry 6), namely, the content of the linear
dichlorohexasilane 1e in the reaction mixture was only
0.5%. Dichloro-substituted cyclosilane 2b was formed as
the major reaction product. As shown previously
dichlorohexasilane 1e but also by cleavage of the Siꢀ
/Me
bonds in the initial cyclosilane 2 to give its monochloro
2a and dichloro 2b derivatives.
Cyclosilane 2 reacts with TiCl4 in a similar way, i.e.,
with Siꢀ
/
Si and Siꢀ
/
Me bond cleavage in cyclosilane 2 to
[2,27,29ꢀ
isomers, namely, 1,3-dichlorocyclosilane (2b?) and 1,4-
dichlorocyclosilane (2bƒ) (in Â1:1 ratio), which are, in
/
31], this product was a mixture of structural
give dichlorooligosilanes 1a
/c, e and monochlorocyclo-
ꢀ
silane 2a [9,27]. The reaction of cyclosilane 2 with SnCl4
and TiCl4 in CH2Cl2 proceeds slowly with a relatively
low degree of conversion of the initial cyclic compound
2. It was also shown [27] that in the absence of a solvent,
the degree of conversion of cyclosilane 2 was 100% after
/
turn, mixtures of cis- and trans-isomers (see Section 3,
29Si-NMR spectra of cyclosilanes 2b? and 2bƒ). A very
reactive chlorinating agent for cyclosilane 2 is SbCl5.
Treatment of cyclosilane 2 with SbCl5 in a 1:2 ratio at
25 8C in the absence of a solvent bring about a vigorous
exothermal reaction with 100% conversion of cyclosi-
lane 2 over a period of several seconds; this gives not
4 h, linear dichlorooligosilanes 1a
the only products.
/
c, e being formed as
ꢀ
In this respect, we studied the reaction of several main
group metal chlorides and transition metal chlorides
(SnCl4, SbCl5, HgCl2, CuCl2, FeCl3, TiCl4, ZrCl4,
MoCl5, WCl6) with cyclosilane 2 in the absence of a
solvent at elevated temperatures. Under these conditions
(Scheme 1, Table 1) cyclosilane 2 reacts with the above
only chloro-substituted cyclosilanes 2aꢀ
/d but also linear
dichlorooligosilanes 1a
chloro-substituted oligisilanes was Â
the reaction in solutions, not only Siꢀ
/
c, e (the ratio of linear to cyclic
ꢀ
bonds of cyclosilane 2 are cleaved in the solvent-free
reaction.
/2:1). Thus, unlike
/
Me but also SiꢀSi
/
mentioned metal chlorides with cleavage of its Siꢀ
SiꢀMe bonds to give linear and cyclic chloro-substituted
permethyloligosilanes.
It should be noted that tin and mercury chlorides
react with cyclosilane 2 mainly cleavage of the SiꢀSi
bond giving predominantly linear dichlorooligosilanes
/
Si and
/
The influence of the reaction conditions on the
conversion of cyclosilane 2, on the yield and composi-
tion of the reaction products and on the ratio between
them was studied in relation to the reaction of 2 with
/
SnCl4. An increase in the reaction times (cf. entries 1ꢀ
/3,
1a
2a
/
c, e (the content of chloro-substituted cyclosilanes
ꢀ
4 and 5 in Table 1) results in a higher yield of linear
dichlorooligosilanes 1a c, e and a lower content of
chloro-substituted cyclosilanes 2a c in the reaction
/
c in the products did not exceed 7.5%), the degree of
2
ꢀ
/
conversion of cyclosilane
being rather high
ꢀ
/
ꢀ
products. In addition, the content of short-chain linear
oligomers 1a and 1b increases and the content of
dichlorotetrasilane 1c and dichlorohexasilane 1e de-
creases. Evidently, this is due to an increase in the
intensity of Siꢀ
/
Si bond cleavage in oligomers 1c and 1e
following an increase in the reaction time. For equal
reaction times, transition from 1:1 ratio of cyclosilane 2
Scheme 1.

Table 1
Conditions and products of the reaction of cyclosilane 2 with metal chlorides MClk
Entry
MClk
2:MClk
T (8C)
t (h)
Composition of the reaction mixture (%) a
Yield of 1
Conversion of 2
1a
7.5
1b
1c
9.6
1e
2
2a
3.9
2b
1.6
2c
(%) b
(%) c
1
SnCl4
SnCl4
SnCl4
SnCl4
SnCl4
SbCl5
SbCl5
HgCl2
CuCl2
CrCl3
FeCl3
TiCl4
ZrCl4
1:1
1:1
1:1
1:2
1:2
1:1
1:2
1:2
1:1
1:2
1:1
1:1
1:1
1:1
1:1
175
175
175
175
175
25
0.5
1
11.3
14.8
19.1
34.7
37.0
46.1
44.3
40.2
1.5
18.1
14.2
10.9
0.4
1.9
1.6
0.4
4.9
1.6
2.0
19.3 e
1.6
6.3
86.5
87.2
89.5
78.9
86.9
0.5
82.6
86.5
89.8
99.5
100
2
9.0
13.5
29.9
41.5
11.3
13.5
25.8
18.7
3.4
0.9
2.0
0.8
5.4
4.5
0.7
2.1
0.2
0.3
2.2
6.4
14.0
7.5
1.4
1.5
3
2
4
1
0.8
5
2
ꢀ/
0.5
3.1
ꢀ
2.8
/
0.4
d
6
2
0.002
ꢀ/
ꢀ/
ꢀ/
89.3
6.8
97.2
100
7
25
43.4
30.0
5.8
11.4
40.8
9.6
0.3
3.6
9.2
1.9
6.3
9.4
10.8
21.9
4.6
0.4
2.3
9.3
2.2
4.4
5.9
ꢀ
/
66.3
86.6
53.8
33.0
53.5
55.5
27.3
40.2
34.6
8
210
180
210
180
175
200
185
205
2
1
2
2
3
2
3
1
2.1
1.8
44.3
89.7
84.3
21.2
25.7
27.4
6.9
1.1
98.2
60.2
10.3
19.6
81.3
80.2
78.2
94.3
9
16.1
2.6
11.2
6.7
10
11
12
13
14
15
0.1
1.4
ꢀ/
ꢀ/
5.7
2.4
8.0
1.9
28.4
23.4
17.8
6.7
16.4
16.2
10.1
4.6
5.3
19.0 f
9.1
MoCl5
WCl6
10.9
17.8
11.8 g
a
Unidentified by-products were neglected.
b
c
d
e
f
Total yield of oligomers 1a
/
c, e from all reaction products (including unidentified ones) and in relation to the reacted cyclosilane 2 (according to GLC).
ꢀ
Determined by GLC.
The reaction was carried out in CCl4.
The reaction mixture contains 0.7% polychloro-substituted cyclosilanes 2d.
The reaction mixture contains 3.3% polychloro-substituted cyclosilanes 2d.
The reaction mixture contains 29.4% polychloro-substituted cyclosilanes 2d.
g

20
A.I. Chernyavskii et al. / Journal of Organometallic Chemistry 679 (2003) 17ꢀ23
/
to SnCl4 to 1:2 ratio (cf. entries 2 with 4 and 3 with 5 in
Table 1), allows one to attain virtually 100% conversion
of cyclosilane 2 with simultaneous sharp decrease (to
also entries 10, 14 and 15 in Table 2) led to an increase in
the conversion of polysilane 3, a rise in the amount of
short-chain oligosilanes 1a, b and a decrease in the
0ꢀ/1.5%) in the content of dichlohexasilane 1e in the
amount of long-chain oligosilanes 1dꢀh. An analogous
/
reaction products. In addition, the content of short-
chain oligomers 1a and 1b increases two to threefold.
effect was observed when the reaction temperature or
the duration of the process was increased. The highest
yields of long-chain oligosilanes 1dꢀh were achieved
/
when polysilane 3 and SnCl4 were taken in a ratio of 2:1
and the reaction was carried out at 125 8C (entry 2).
However, the conversion of polysilane 3 in the latter
case was only 56%. According to the data from GLC
and 29Si-NMR spectroscopy, none of the reactions
2.2. Reactions polysilane 3 with metal chlorides
The reaction of polysilane 3 with the above mentioned
metal chlorides in the absence of a solvent at high
temperature proceeds with the cleavage of the polysilane
chain to form a mixture of homologs, viz., dichloroo-
ligosilanes 1 (Scheme 2).
under study afforded dichlorooligosilanes 1 with m ꢀ
/
9. The optimum reaction conditions, which allow one to
attain a high conversion of polysilane 3 and to obtain
The conversion of polysilane 3 was rather high (80ꢀ
/
long-chain dichlorooligosilanes 1dꢀh in high yields, are
/
100%) in virtually all reactions (Table 2). However, the
reactions of polysilane 3 with transition metal chlorides
(except for HgCl2) afforded oligosilanes 1 in lower total
yields (no higher than 55%) as compared to those
obtained in the reactions of main group metal chlorides
(except for SbCl5). Apparently, the relatively low yields
of oligosilanes 1 obtained in the reactions of transition
metal chlorides with polysilane 3 are attributable to the
fact that these reactions, like those with cyclohexasilane
as follows: the reaction temperature is 180 8C, the
reaction time is 3 h and polysilane 3 to SnCl4 ratio is
4:1 (for SnCl4); the corresponding conditions for HgCl2
are 180 8C, 2 h and 2:1.
The procedure for the synthesis of dichlorooligosi-
lanes 1 based on the reactions of polysilane 3 with metal
chlorides has advantages over known procedures. Thus,
this procedure makes it possible to prepare dichloroo-
ligosilanes 1 containing more than six Si atoms in the
oligomer chain, dichloropentasilane 1d (which has been
previously prepared from difficultly accessible (Me2Si)5
or Ph(Me2Si)5Ph) is generated rather easily and inso-
luble unfusible polysilane 3, which is formed as a by-
product in the synthesis of cyclosilanes [32,33], is
utilized.
2, led not only to the cleavage of the Siꢀ
/
Si bonds in the
initial polysilane 3 but also to the partial replacement of
the Me groups by Cl atoms both in polysilane 3 and the
resulting oligosilanes 1. As a result, the reaction
mixtures contained large amounts of by-products with
a consequent decrease in the yield of the target products.
It should be noted that, as in our investigation
described above, we found that SbCl5 exhibits higher
chemical activity as compared to the rest of metal
chlorides. The reaction of polysilane 3 with SbCl5 was
completed in several seconds at room temperature and
was accompanied by heat evolution. In addition, in the
reactions with polysilane 3 SbCl5 behaved analogously
to transition metal chlorides: conversion of polysilane 3
was 100%, whereas the yield of oligosilanes 1 was only
54%.
3. Experimental
3.1. General comments
All reactions were monitored by GLC. The GLC
analysis was carried out on a LKhM-8MD chromato-
graph (a 0.3ꢄ100 cm stainless steel column; 5% SE-30
/
on Chromaton N-AW-DMCS; a thermal conductivity
detector; the temperature was increased from 30 to
300 8C with a rate of 128 minꢂ1; helium as the carrier
gas). GC/MS measurements were performed on a
The highest yields of dichlorooligosilanes 1 were
achieved in the reactions with the use of SnCl4 and
HgCl2 as chlorinating agents (see Table 2). It was
established that variation of conditions of the reaction
between polysilane 3 and these metal chlorides makes it
possible to control to certain extent the length of
oligomer chain in the resulting dichlorooligosilanes 1.
It was found that a decrease polysilane 3: metal chloride
ratio in the reactions performed at the same temperature
over the same period of time (cf. entries 1, 5 and 8 and
Kratos-MS-890 instrument (a 15 mꢄ0.32 mm capillary
/
column; SE-30 liquid phase; helium as the carrier gas;
the temperature was programmed to rise from 30 to
270 8C at a rate of 128 minꢂ1; ionization energy was 70
eV). 29Si-NMR spectra (79.46 MHz) were recorded on a
Bruker WP-400 SY spectrometer. Samples were dis-
solved in CDCl3 and Me4Si was used as internal
standard. Elemental analysis were performed by the
Laboratory of Microanalysis of the Institute of Orga-
noelement Compounds.
All reactions were carried out under an atmosphere of
argon. Cyclosilane 2 was prepared by catalytic depoly-
Scheme 2.

Table 2
Conditions and products of the reaction of polysilane 3 with metal chlorides MClk
a
8
Entry
MClk
3:MClk
T (8C)
t (h)
Cl(Me2Si)m Cl/amꢁ2Cl(Me2Si)m Cl (%) at different m
Conversion of 3
Yield of 1aꢀg
/
2
3
4
5
6
7
8
(%) b
(%) c
1
SnCl4
SnCl4
SnCl4
SnCl4
SnCl4
SnCl4
SnCl4
SnCl4
SbCl5
HgCl2
HgCl2
HgCl2
HgCl2
HgCl2
HgCl2
HgCl2
HgCl2
CuCl2
CrCl3
FeCl3
TiCl4
4:1
2:1
2:1
2:1
2:1
2:1
1:1
1:1
2:1
2:1
2:1
2:1
1:1
1:1
1:2
1:2
1:2
1:1
2:1
1:1
2:1
2:1
2:1
180
125
180
180
180
210
180
180
20
3
13.2
13.7
22.1
26.4
27.3
34.8
11.0
15.0
49.4
6.5
31.1
30.4
41.3
44.3
45.3
37.6
46.1
49.7
22.0
47.6
47.3
53.2
54.7
53.3
51.2
51.8
52.9
30.0
29.5
30.2
22.0
30.6
16.1
26.4
20.7
20.9
21.9
23.3
16.3
35.3
29.5
17.6
27.6
23.4
17.3
16.9
8.8
18.0
14.3
12.4
6.6
7.4
8.8
3.3
0.8
0.4
2.2
0.2
2.7
6.7
1.2 d
5.4 d
87.2
56.6
100
100
100
100
100
100
100
94.3
97.2
100
96.1
100
100
100
100
97.3
38.3
100
100
100
77.9
95.5
80.8
87.3
88.3
90.5
82.4
87.1
89.9
54.2
91.9
93.4
92.9
94.6
92.3
90.5
82.5
85.9
46.2
53.9
51.0
55.5
24.5
55.4
2
3
3
1
Traces
*
/
4
2
*
/
*
/
5
3
3.7
9.1
*
/
*
/
6
0.5
1
*
/
*
/
7
7.4
5.8
*
/
*
/
8
3
*
/
*
/
*
/
9
0.003
2
7.3
2.4
4.9
1.3
1.0
*
/
10
11
12
13
14
15
16
17
18
19
20
21
22
23
180
230
230
180
180
180
230
230
180
210
180
180
200
200
12.4
10.9
0.7
Traces
0.5
2
16.4
28.8
25.7
37.9
42.8
43.6
45.0
46.2
3.9
2.0
Traces
0.3
Traces
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
0.5
2
2.4
Traces
ꢀ/
ꢀ/
ꢀ/
ꢀ/
6.9
17.4
4.5
ꢀ/
ꢀ/
ꢀ/
ꢀ/
1.7
11.7
1.1
5.1
ꢀ/
ꢀ/
ꢀ/
ꢀ/
1.2
9.3
2
6.0
4.6
0.5
2
2.4
1
13.4
20.8
12.2
20.4
14.9
8.0
0.6 c
7.4 d
2
1
52.0
35.6
54.5
75.9
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
ꢀ/
3
16.9
MoCl5
WCl6
1
ꢀ/
ꢀ/
ꢀ/
ꢀ/
1
a
With respect to the ꢀ
/
SiMe2ꢀ
In all experiments, we used polysilane 3 from the same preparation. Its conversion was determined after separation of the precipitate and dissolution of the metal chloride salt in the corresponding
solvent.
/
unit.
b
c
In relation to the reacted polysilane 3.
d
Traces (B
/
0.1%) of dichlorononasilane 1h (mꢁ9).
/

22
A.I. Chernyavskii et al. / Journal of Organometallic Chemistry 679 (2003) 17ꢀ23
/
merization of polysilane 3 as described in Ref. [9].
Polysilane 3 was obtained according to a modified
procedure [34]. Immediately prior to the use, TiCl4,
SnCl4 and SbCl5 were distilled in an N2 flow, while the
other metal chlorides were used as received. CCl4 was
dried by distillation over P2O5 in an N2 flow.
the reaction products was separated using a separating
funnel. Hexane was removed on a rotary evaporator.
The initial cyclosilane 2 and monochloro-substituted
cyclosilane 2a were removed from crystalline residue by
sublimation (80 8C, 1 Torr). The residue after sublima-
tion was recrystallized from anhydrous pentane to give
6.7 g (60%) of a mixture of 1,3-(2b?) and 1,4-dichloro-
3.2. Reaction of cyclosilane 2 with SnCl4 (typical
procedure) (Table 1, entry 2)
cyclosilane (2bƒ) isomers (Â
2b? (cis-, trans-isomers): 15.42, 14.90 (SiCl), ꢂ
37.62 (ClSiSiSiCl), ꢂ38.94, ꢂ39.36 (SiSiSiCl), ꢂ
42.48, ꢂ44.59 (SiSiSi);
2bƒ (cis-, trans-isomers): 15.60, 15.13 (SiCl), ꢂ
39.92 (ClSiSi2SiCl).
/
1:1). 29Si-NMR: d:
/37.05,
ꢂ
/
/
/
/
Cyclosilane 2 (34.9 g, 0.1 mol) was placed in an
ampoule equipped with a branch for reactant introduc-
tion and a Teflon stopcock, SnCl4 (26.1 g, 0.1 mol) was
added and the ampoule was placed in an oil bath
preheated to 175 8C. The reaction mixture was kept at
this temperature with vigorously stirring for 1 h. The
ampoule was cooled and 50 ml of anhydrous CCl4 was
added. The SnCl2 precipitate was filtered off and
/
/39.66,
ꢂ
/
3.4. Reaction of polysilane 3 with SnCl4 (typical
procedure) (Table 2, entry 1)
Polysilane 3 (40.0 g, 0.688 mol) was placed in an
argon-filled tube equipped with an inlet pipe for the
introduction of reagents, a Teflon stopcock and a
magnetic stirrer. Then SnCl4 (44.8 g, 0.172 mol) was
added. The tube was placed in an oil bath preheated to
180 8C and kept for 3 h with vigorously stirring. The
reaction mixture was cooled and 50 ml of anhydrous
CCl4 was added. The precipitate of SnCl2 and unreacted
polysilane 3 were filtered off and washed with anhy-
washed with CCl4 (2ꢄ10 ml). The solvent was evapo-
/
rated and the residue was analyzed by GLC (see Table
1). Fractionation of the residue gave:
5.6 g (10.0% relative to the reacted cyclosilane 2) of
dichlorodisilane 1a. B.p.: 148ꢀ
17.21;
8.1 g (16.5%) of dichlorotrisilane 1b. B.p.: 84ꢀ
(10 Torr). 29Si-NMR: d 24.98 (ClSi), ꢂ
43.71 (ClSiSi);
5.7 g (12.7%) of dichlorotetrasilane 1c. B.p.: 111ꢀ
112 8C (5 Torr). 29Si-NMR: d 26.26 (ClSi), ꢂ
42.68
(ClSiSi).
After evaporation of lower dichlorooligosilanes 1a
/
148.5 8C. 29Si-NMR: d
/
85 8C
/
/
drous CCl4 (3ꢄ10 ml). The precipitate was treated with
/
/
acetone to dissolve SnCl2. Polysilane 3 was filtered off
and dried at 60 8C in vacuo to a constant weight.
Polysilane 3 was obtained in a yield of 5.1 g (conversion
was 87.2%). The solvent was distilled off from the
solution of dichlorooligosilanes 1 in CCl4 and the
residue was analyzed by GLC (see Table 2). Fractiona-
tion of the residue gave:
/c,
ꢀ
the initial cyclosilane 2 and chloro-substituted cyclosi-
lanes 2a and 2b were removed by sublimation. Distilla-
tion of the residue gave 20.8
dichlorohexasilane 1e. B.p.: 166ꢀ167 8C (1 Torr), m.p.
45ꢀ 40.90 (ClSiSi),
46 8C. 29Si-NMR: d 26.35 (ClSi), ꢂ
39.95 (ClSiSiSi).
Entries 1, 3ꢀ5 and 7ꢀ
g
(49.5%) of
/
/
/
5.4 g (10.1% relative to the reacted polysilane 3) of
ꢂ
/
dichlorodisilane 1a. B.p.: 147.5ꢀ
17.23;
13.0 g (27.9%) of dichlorotrisilane 1b. B.p.: 85ꢀ
(10 Torr). 29Si-NMR: d 24.95 (ClSi), ꢂ
43.77 (ClSiSi);
11.0 g (25.5%) of dichlorotetrasilane 1c. B.p.: 110ꢀ
111 8C (5 Torr). 29Si-NMR: d 26.22 (ClSi), ꢂ
42.62
(ClSiSi);
7.6 g (18.3%) of dichloropentasilane 1d. B.p.: 95ꢀ
96 8C (0.5 Torr). 29Si-NMR: d 26.26 (ClSi), ꢂ
41.65
(ClSiSi), ꢂ41.12 (ClSiSiSi);
3.1 g (7.8%) of dichlorohexasilane 1e. B.p.: 139ꢀ
141 8C (0.5 Torr). 29Si-NMR: d 26.21 (ClSi), ꢂ
40.89
(ClSiSi), ꢂ40.01 (ClSiSiSi);
1.1 g (2.9%) of dichlorotetradecamethylheptasilane 1f.
B.p.: 179ꢀ181 8C (0.5 Torr). Anal. Calc. for
/
148 8C. 29Si-NMR: d
/
/
15 were carried out in a similar
way (entry 7 without heating) except that the residue
after removal of CCl4 was not fractionated but was
analyzed by GLC.
/
86 8C
/
/
/
3.3. Reaction of cyclosilane 2 with SbCl5 (Table 1, entry
6)
/
/
A solution of SbCl5 (11.8 g, 39.4 mmol) in 30 ml of
anhydrous CCl4 was added dropwise to a solution of
cyclosilane 2 (10.0 g, 28.7 mmol) in 50 ml of anhydrous
CCl4 cooled to 0 8C. The reaction mixture was vigor-
ously stirred for 2 h at 20 8C. The precipitate was filtered
/
/
/
/
off and washed with anhydrous hexane (2ꢄ/10 ml). The
/
solvents were removed on a rotary evaporator and the
initial cyclosilane 2 and the reaction products (chloro-
substituted cyclosilanes 2a c) were extracted from the
C14H42Cl2Si7: C, 35.18; H, 8.86; Cl, 14.83; Si, 41.13%.
Found: C, 35.44; H, 8.63; Cl, 14.27; Si, 40.78%. 29Si-
/
NMR: d 26.37 (ClSi), ꢂ
SiSi), ꢂ37.91 (ClSiSiSiSi). MS: m/e (rel. int.,%) 463
[Mꢃ ꢀ
Me, 0.8], 325 (Si5Me10Cl, 11.8), 267 (Si4Me8Cl,
100), 209 (Si3Me6Cl, 35.4), 174 (Si3Me6, 11.1), 173
/
41.05 (ClSiSi), ꢂ
/
39.80 (ClSi-
ꢀ
residue with anhydrous hexane (3ꢄ/10 ml). Acetonitrile
/
(6 ml) was added to the resulting solution for deactiva-
tion of antimony compounds and the hexane solution of
/

A.I. Chernyavskii et al. / Journal of Organometallic Chemistry 679 (2003) 17ꢀ
/23
23
[9] A.I. Chernyavskii, B.G. Zavin, Izv. Akad. Nauk, Ser. Khim.
(1997) 1513. [Russ. Chem. Bull. 46 (1997) 1449 (English transla-
tion)].
(Si3Me5CH2, 13.5), 159 (Si3Me5, 11.5), 131 (Si2Me5,
28.2), 116 (Si2Me4, 9.2), 115 (Si2Me3CH2, 7.5), 73
(SiMe3, 55.6);
[10] N.A. Chernyavskaya, V.I. Aleksinskaya, A.I. Chernyavskii, Izv.
Akad. Nauk, Ser. Khim. (1998), 544. (Russ. Chem. Bull. 47 (1998)
526 (English translation)).
0.5 g (1.3%) of dichlorohexadecamethyloctasilane 1g.
B.p.: 185ꢀ187 8C (0.06 Torr). Anal. Calc. for
/
[11] A.I. Chernyavskii, A.I. Belokon’, N.A. Chernyavskaya, V.I.
Aleksinskaya, B.G. Zavin, Yu.S. Nekrasov, Izv. Akad. Nauk,
Ser. Khim. (1999) 1729. (Russ. Chem. Bull. 48 (1998) 1707
(English translation)).
C16H48Cl2Si8: C, 35.84; H, 9.02; Cl, 13.23; Si, 41.91%.
Found: C, 35.41; H, 8.85; Cl, 12.98; Si, 41.43%. 29Si-
NMR: d 26.43 (ClSi), ꢂ
/
40.89 (ClSiSi), ꢂ39.67 (ClSi-
/
SiSi), ꢂ37.69 (ClSiSiSiSi).
/
[12] A. Kleewein, H. Stiiger, Monatsh. Chem. 130 (1999) 69.
[13] A.I. Chernyavskii, N.A. Chernyavskaya, V.I. Aleksinskaya, B.G.
Zavin, J. Organomet. Chem. 579 (1999) 328.
According to the GLC data, the residue was a mixture
of dichlorooctasilane 1g and dichlorooctadecamethyl-
nonasilane 1h in a ratio of 1:1.4.
[14] A.I. Chernyavskii, D.Yu. Larkin, N.A. Chernyavskaya, Izv.
Akad. Nauk, Ser. Khim. (2002) 165. (Russ. Chem. Bull., Int.
Ed. 51 (2002) 175).
Entries 2ꢀ23 were carried out in analogously (entry 9
/
without heating) but the residues obtained after the
removal of CCl4 were analyzed by GLC rather than
distilled (see Table 2).
[15] A.I. Chernyavskii, E.G. Kononova, M.I. Buzin, N.A. Chernyavs-
kaya, Izv. Akad. Nauk, Ser. Khim., [Russ. Chem. Bull., Int. Ed.
52, (2003) 952].
[16] M. Kumada, M. Yamaguchi, Y. Yamamoto, I. Nakajima, K.
Shina, J. Org. Chem. 21 (1956) 1264.
[17] M. Kumada, M. Ishikawa, J. Organomet. Chem. 1 (1963) 153.
[18] H. Sakurai, R. Tominaga, T. Watanabe, M. Kumada, Tetrahe-
dron Lett. (1966) 5493.
Acknowledgements
[19] M. Ishikawa, M. Kumada, H. Sakurai, J. Organomet. Chem. 23
(1970) 63.
This work was financially supported by the Russian
Foundation for Basic Research (Grant 00-03-33189).
The authors are also grateful to Dr A.I. Belokon’ and
Dr E.V. Voronstov for recording the mass spectrum and
NMR spectra, respectively.
[20] M. Kumada, M. Ishikawa, S. Maeda, J. Organomet. Chem. 2
(1964) 478.
[21] M. Kumada, M. Ishikawa, S. Sakamoto, S. Maeda, J. Organo-
met. Chem. 17 (1969) 223.
[22] B.G. Zavin, A.I.Chernyavskii, Ya.S. Vygodskii, N.E. Brandu-
kova, Dokl. Akad. Nauk 336 (1994) 365. (Dokl. Chem. 336 (1994)
97 (English translation)).
References
[23] P.K. Sen, D. Ballard, H. Gilman, J. Organomet. Chem. 15 (1968)
237.
[1] F.K. Mitter, G. Pollhammer, E. Hengge, J. Organomet. Chem.
314 (1986) 1.
[24] W. Wojnowski, C.J. Hurt, R. West, J. Organomet. Chem. 124
(1977) 271.
[2] F.K. Mitter, E. Hengge, J. Organomet. Chem. 332 (1987) 47.
[3] E. Hengge, P.K. Jenkner, Z. Anorg. Allg. Chem. 560 (1988) 27.
[4] E. Hengge, P. Gspaltl, A. Spielberger, J. Organomet. Chem. 479
(1994) 165.
[25] P.K. Jenkner, A. Spielberger, E. Hengge, J. Organomet. Chem.
427 (1992) 161.
[26] H. Gilman, S. Inoue, J. Org. Chem. 29 (1964) 3418.
[27] B. Derczewski, W. Wojnowski, J. Prakt. Chem. 332 (1990) 229.
[28] M. Ishikawa, M. Kumada, Synth. Inorg. Met.-Org. Chem. 1
(1971) 191.
[5] K. Kumar, M.H. Litt, J. Polym. Sci., Part C Polym. Lett. 26
(1988) 25.
´
[6] J. Chojnowski, J. Kurjata, S. Rubinsztajn, M. .Scibiorek, in: A.R.
[29] E. Hengge, M. Eibl, J. Organomet. Chem. 428 (1992) 335.
[30] A. Spielberger, P. Gspaltl, H. Siegl, E. Hengge, K. Gruber, J.
Organomet. Chem. 499 (1995) 241.
Bassindale, P.P. Gaspar (Eds.), Frontiers of Organosilicon
Chemistry, The Royal Society of Chemistry, Cambridge, 1991,
p. 70.
[31] M. Eibl, U. Katzenbeisser, E. Hengge, J. Organomet. Chem. 444
(1993) 29.
´
[7] J. Chojnowski, W. Fortuniak, N. Gladkova, M. Pluta, M. .Sci-
biorek, B. Zavin, J. Inorg. Organomet. Polym. 5 (1995) 7.
´
[8] J. Kurjata, M. Scibiorek, W. Fortuniak, J. Chojnowski, Organo-
metallics 18 (1999) 1259.
[32] E. Carberry, R. West, J. Am. Chem. Soc. 91 (1969) 5440.
[33] R. West, L. Brough, W. Wojnowski, Inorg. Synth. 19 (1979) 265.
[34] J.P. Wesson, T.C. Williams, J. Polym. Sci. Part A 17 (1979) 2833.