1,2-Dithiolate derivatives of monosilanes and disilanes

Article abstract of DOI:10.1016/S0022-328X(00)00432-0

The reactions of the chlorosilanes Me₃SiCl, Me₂SiCl₂, MeSiCl₃, SiCl₄, SiClMe₂-SiClMe₂ and SiCl₂Me-SiCl₂Me with ethane-1,2-dithiol and benzene-1,2-dithiol have been investigated. All silicon dithiolates formed have been characterized by ¹H-, ¹³C- and ²⁹Si-NMR. The formation of five-membered rings SiS₂C₂ is accompanied by a strong downfield shift of the ²⁹Si-NMR signals. The molecular structures of Me₂SiS₂(o-C₆H₄) (6), Si[S₂(o-C₆H₄)]₂ (7) and [MeSiS₂(o-C₆H₄)]₂ (11) are reported. The found geometries are compared with the results of DFT calculations at the B3LYP/6-31G* level, and the observed partial planarizations of the SiS₄ tetrahedrons in the spiro compounds Si[(SCH₂)₂]₂ (1) and 7 are discussed.

Full text of DOI:10.1016/S0022-328X(00)00432-0

www.elsevier.nl/locate/jorganchem
Journal of Organometallic Chemistry 612 (2000) 133–140
1,2-Dithiolate derivatives of monosilanes and disilanes
U. Herzog a,*, U. Bo¨hme a, G. Rheinwald b
a Institut fu¨r Anorganische Chemie der TU Bergakademie Freiberg, Leipziger Str. 29, D-09596 Freiberg, Germany
b Institut fu¨r Chemie, Lehrstuhl Anorganische Chemie, TU Chemnitz, Straße der Nationen 62, D-09111 Chemnitz, Germany
Received 2 June 2000; received in revised form 23 June 2000
Abstract
The reactions of the chlorosilanes Me3SiCl, Me2SiCl2, MeSiCl3, SiCl4, SiClMe2–SiClMe2 and SiCl2Me–SiCl2Me with
1
ethane-1,2-dithiol and benzene-1,2-dithiol have been investigated. All silicon dithiolates formed have been characterized by H-,
13C- and 29Si-NMR. The formation of five-membered rings SiS2C2 is accompanied by a strong downfield shift of the 29Si-NMR
signals. The molecular structures of Me2SiS2(o-C6H4) (6), Si[S2(o-C6H4)]2 (7) and [MeSiS2(o-C6H4)]2 (11) are reported. The found
geometries are compared with the results of DFT calculations at the B3LYP/6-31G* level, and the observed partial planarizations
of the SiS4 tetrahedrons in the spiro compounds Si[(SCH2)2]2 (1) and 7 are discussed. © 2000 Elsevier Science B.V. All rights
reserved.
Keywords: Monosilanes; Disilanes
compared to that of the acyclic mercapto derivatives
Me2Si(SMe)2 (28.14 ppm [5]) or Me2Si(SBu)2 (24.8 ppm
[6]) containing the same first coordination sphere at
silicon, the cyclic compounds exhibit a strong downfield
shift. If the ring is expanded to a six-membered ring in
Me2Si(SCH2)2CH2 the 29Si-NMR shift decreases to
22.53 ppm [4]. This exceptional low field shift in five-
membered rings is also found in cyclic and polycyclic
silthianes [7] and can also be used as an indication of
the formation of this ring size. A compilation of struc-
tural details (bond lengths and angles) as well as 29Si-
NMR shifts of silicon sulfur compounds can be found
in [8].
1. Introduction
Since the questionable conclusion of Mayer et al. [1]
about a planar tetracoordinated silicon atom in bis(o-
phenylenedioxy)silane, some interest has arisen in
the coordination geometry of silicon in orthothiosilicic
acid esters and spiro-bis(ethane-1,2-dithio)silane,
Si[(SCH2)2]2 (1). Wojnowski et al. [2] reported the X-
ray structure of 1 showing some deviation of the ge-
ometry at silicon from a tetrahedron. The angles
S–Si–S which are part of five-membered rings are
decreased to 100.1° and 100.5° respectively. Further-
more, the spiro angle between the two S–Si–S% planes
is reduced to 74.4°. This strong distortion was assigned
as a result of an intramolecular anomeric effect of
interactions between 3p lone pair orbitals of sulfur with
s*(Si–S) antibonding orbitals [3]. Besides this spiro
compound, which is also remarkable because of its
29Si-NMR shift of +57.47 ppm [4], only a few silicon
derivatives of dithiols have been synthesized. If the
29Si-NMR shift of Me2Si(SCH2)2 (2, 41.67 ppm [4]) is
In this work we will report on the synthesis and
properties of several ethane-1,2-dithiol and benzene-
1,2-dithiol derivatives of mono- and disilanes in order
to obtain a better understanding of the unusual NMR
parameters and structures.
2. Results and discussion
2.1. Ethane-1,2-dithiolate deri6ati6es of
methylchloromonosilanes
* Corresponding author. Tel.: +49-3731-394343; fax: +49-3731-
395058.
E-mail address: herzog@merkur.hrz.tu-freiberg.de (U. Herzog).
The reaction of Me3SiCl with ethane-1,2-dithiol and
triethylamine yields the acyclic 1,2-bis(trimethylsilyl-
0022-328X/00/$ - see front matter © 2000 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(00)00432-0

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U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
Table 1
29Si, 13C and 1H-NMR chemical shifts (ppm) and coupling constants
(Hz) of ethane-1,2-dithiolate derivatives of monosilanes and disilanes
The NMR data of 2 and 3 are summarized in Table
1. Whereas lSi of 3 is only 1.2 ppm low field from the
thiobutyl derivative Me3SiSBu [6], 2 which possess a
five-membered ring SiS2C2, exhibits a lSi 16.9 ppm
downfield from the comparable thiobutyl derivative
Me2Si(SBu)2. Furthermore the lC and lH of the ethyl-
ene unit are shifted significantly from the values found
in ethane-1,2-dithiol (lC 28.6 ppm, lH (CH2) 2.75 ppm)
and 3.
More complicated is the reaction of MeSiCl3 with
HS(CH2)2SH and NEt3. If the reaction is carried out in
a 1:1:2 molar ratio three products can be observed.
Besides the bridged dimer (CH2S)2SiMe–S(CH2)2S–
MeSi(SCH2)2 (4a) the partial substitution product
(CH2S)2SiClMe (4b) and (CH2S)2SiMe–S(CH2)2SH (4c)
can be observed. The 29Si-NMR shifts of 4a–4c are
similar and are, in accordance with the formation of a
five-membered ring SiS2C2, 16.3 ppm (4a), 17.3 ppm
(4b) and 16.4 ppm (4c) downfield from the acyclic
analogously thiobutyl substituted silanes MeSi(SBu)3
and MeSiCl(SBu)2 [6], respectively. Also the ethylene
units, which are part of the rings, exhibit lC and lH
values at relatively low field, see Table 1. If the reaction
of MeSiCl3 with HS(CH2)2SH and NEt3 is repeated in
a 1:1.5:3 molar ratio, only 4a and 4c are formed in a 4:1
ratio.
The analogous reaction of SiCl4 yields the known
spiro compound 1; no further products, like a semispiro
compound (CH2S)2SiCl2, could be detected by NMR if
the starting molar ratio was changed to 1:1:2. DFT
calculations of 1 at the B3LYP/6-31G* level yielded an
optimized structure which reflects well the observed
deviations from the tetrahedral geometry at silicon, see
Table 2 and Fig. 1. The calculated spiro angle of 77.2°
is close to the reported value of 74.4°. If this angle is
thio)ethane (3) whereas treatment of Me2SiCl2 with
ethane-1,2-dithiol and triethylamine resulted in the for-
mation of cyclic 2 with no indication of any acyclic
by-products:
Table 2
Comparison of the crystal structure geometry of 1 with the results of the DFT calculation at the B3LYP/6-31G* level
Parameter
Crystal structure [2]
DFT calculation
Optimized geometry
Geometry with fixed spiro angle
,
d(SiS) (A)
2.115(1) and 2.117(1)
1.815(3) and 1.817(3)
1.520(9) and 1.523(6)
74.4
2.157
1.852
1.525
77.2
2.161
1.853
1.525
90
,
d(SC) (A)
,
d(CC) (A)
Spiro angle (°)
ÚSSiS (within the ring) (°)
ÚSSiS (between the rings) (°)
ÚCSSi (°)
ÚCCS (°)
Total energy (H)
100.1(1) and 100.5 (1)
104.6(1) and 124.7(1)
96.8(1) and 97.2(1)
111.1(2) and 111.2(2)
100.5
106.6 and 122.7
96.2
111.3
−2039.62241
−2039.49984
100.6
114.1
96.2
111.6
−2039.61975
−2039.49736
Total energy with zero point correction (H)

U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
135
2.2. Benzene-1,2-dithiolate deri6ati6es of
methylchloromonosilanes
The reactions of Me3SiCl and Me2SiCl2 with ben-
zene-1,2-dithiol and triethylamine yielded 1,2-bis(tri-
methylsilylthio)benzene (5) and 2,2-dimethyl-2-sila-1,3-
dithiaindane (6) respectively, Table 3. Whereas in 5 the
lSi of the SiMe3 units are only 1.0 ppm downfield from
the value found in the similar phenylthiotrimethylsilane
[9], the SiMe2 unit in 6 is shifted 15.4 ppm downfield
from bis(phenylthio)dimethylsilane [9], in agreement
with the formation of a five-membered ring SiS2C2.
Despite the high solubility of 6 even in hexane and its
low melting point, single crystals suitable for X-ray
analysis could be obtained and Fig. 2 shows the molec-
ular structure of 6.
Fig. 1. SCHAKAL plot of the calculated structure of 1 (B3LYP/6-
31G*), hydrogen atoms omitted for clarity, showing the partial
planarization of the SiS4 tetrahedron.
Table 3
If SiCl4 is reacted with benzene-1,2-dithiol and tri-
ethylamine the spiro compound bis(o-phenylene-
dithio)silane (7) is formed. The 29Si-NMR shift of 7
appears at relatively low field although 17 ppm high
field from 1, whereas the Si-NMR shifts of the mono-
cyclic compounds 2 and 6 differ only by 1.1 ppm.
Single crystals of 7 suitable for X-ray analysis could be
obtained; Fig. 3 shows the molecular structure of 7.
Compared to the molecular structure of 6 important
differences can be seen: both SiS2C2 rings in 7 are
planar whereas the SiS2C2 ring in 6 adopts an envelope
conformation with an angle of 20° between the C2S2
and the S2Si planes. While the spiro angle between the
planes C(7)C(8)Si and SiS2 is 90° in 6 (like in an ideal
tetrahedron) this spiro angle between the two five-mem-
bered rings in 7 is reduced to 83.39(0.01)° but this is
still much closer to 90° than the 74.4° found in 1.
Furthermore the angles CSSi and SSiS within the five-
membered rings are enlarged by 1 and 2°, respectively,
in 7 in comparison with 6. The shorter bond distances
SiS in 7 than in 6 confirm the general trend also found
in silthianes that the SiS bond lengths decrease with the
number of sulfur substituents at silicon. Important
bond lengths and angles of 6 and 7 are summarized and
compared with the results of the DFT calculations in
Table 4.
NMR data of benzene-1,2-dithiolates of monosilanes
Fig. 2. Molecular structure of 6.
fixed to 90°, the calculation results in a structure 6.5 kJ
mol−1 higher in energy. This is in contrast to earlier
EHT calculations which yielded an optimized structure
with a spiro angle of 87° [3].
Fig. 3. Molecular structure of 7.

136
U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
Table 4
Comparison of bond lengths and angles of the molecular structures of 6, 7, and 11 with the results of DFT calculations (B3LYP/6-31G*)
Parameter
6
7
11
Observed
Calculated
2.171
Observed
Calculated
2.153
Observed
Calculated
2.363
,
d(SiSi) (A)
2.336(3) a
2.337(3) b
2.150(2) a
2.151(2) a
2.153(2) b
2.154(2) b
1.852(5) a
1.851(6) b
1.781(5) a
1.783(5) a
1.776(5) b
1.779(5) b
89.2(1) a
89.2(2) b
35.3(1) a
33.5(1) b
97.94(7) a
98.08(7) b
93.4(2) a
93.9(2) a
93.9(2) b
94.1(2) b
,
d(SiS) (A)
2.1529(6)
2.1541(7)
2.1299(6)
2.1381(6)
2.177
,
d(SiC) (A)
1.836(2)
1.853(2)
1.773(2)
1.776(2)
1.881
1.883
1.793
1.882
1.794
,
d(SC) (A)
1.778(2)
1.779(2)
1.788
spiro Ú(Si) (°)
90
90
83.39(0.01)
0
90 c
0
90
Envelope Ú in C2S2Si rings (°)
Ú(SSiS) (°)
20.0(1)
98.18(2)
15.3
98.9
97.6
13.1
98.7
97.9
100.08(2)
99.6
98.5
Ú(CSSi) (°)
97.44(5)
97.58(5)
98.40(6)
98.46(6)
a Two independent molecules, molecule a.
b Two independent molecules, molecule b.
c Fixed at 83.4°: total energy +0.8 kJ mol−1
.
the six-membered ring compound 8 which has also been
prepared earlier [10]. In contrast to the five-membered
ring compounds the formation of a six-membered ring
results in a significant high field shift of the 29Si-NMR
signal (see Table 1) of 7.5 ppm in comparison with the
acyclic disilane thiolate BuS(SiMe2)2SBu [6]. Differences
from five-membered ring compounds are also evident in
In contrast to the DFT calculations of 1 the optimized
structure of 7 at the B3LYP/6-31G* level of theory shows
a spiro angle of 90°. But if this angle is fixed to the value
found in the crystal structure the total energy increases
only by 0.8 kJ mol−1. This suggests that the observed
partial planarization in this case may also be a result of
crystal packing forces.
1
the 13C and H chemical shifts of the methylene units in
On the other hand the calculated structures of 6 and
7 parallel the observation that the C2S2Si ring in 6 adopts
an envelope conformation while the C2S2Si rings in 7 are
planar. It can be argued that this planarization of the
five-membered rings in 7 is a result of the non-bonding
interaction of the two orthogonal siladithiaindane ring
systems. An envelope conformation would lead to an
increase in energy by repulsion of the two indane systems.
To sum up, the crystal structures as well as the results
of the DFT calculations of 1 and 7 show important
differences, especially concerning the spiro angles. These
differences are likely to cause the the very different
29Si-NMR chemical shifts of 1 and 7, whereas in all other
cases the ethane-1,2-dithiol and the benzene-o-dithiol
derivatives show very similar lSi values.
8 which appear at approximately 7 ppm (13C) and 0.3
ppm (1H) higher field in comparison with 1, 2 and 4a–4c.
No similar six-membered ring compound is formed in the
reaction of 1,2-dichlorotetramethyldisilane with ben-
zene-1,2-dithiol, the NMR spectra of the reaction prod-
ucts rather suggest the formation of open chain oligomers
[–(SiMe2)2–S(o-C6H4)S–]x.
If 1,1,2,2-tetrachlorodimethyldisilane is reacted with
ethane-1,2-dithiol the formation of either a five-mem-
bered ring compound or six-membered ring compounds
is possible:
2.3. 1,2-dithiolate deri6ati6es of methylchlorodisilanes
The reaction of 1,2-dichlorotetramethyldisilane with
ethane-1,2-dithiol in the presence of triethylamine yields

U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
137
Table 5
Calculated total energies and geometries of 9a–9c (B3LYP/6-31G*)
Parameter
9a
9b
9c
Total energy (H)
Total energy with zero point correction (H)
−2408.97290
−2408.77482
2.363
2.183
99.7
−2408.94512
−2408.74697
2.319
2.177
113.0
−2408.95120
−2408.75302
2.348
2.169/2.175
105.0
,
d(SiSi) (A)
,
d(SiS) (A)
Ú(SSiS) (°)
Ú(CSSi) (°)
96.2
102.0
102.1/105.8
DFT calculations at the B3LYP/6-31G* level of the
possible isomers of Si2Me2(SCH2CH2S)2 (see Table 5
and Fig. 4a–c) predict the isomer 9a with a bis(cy-
clopentyl) structure to be the most stable, see Scheme 1.
The NMR spectra of the resulting product are in
agreement with the formation of five-membered rings
(9a, Table 1). The 29Si-NMR chemical shift is shifted by
14.7 ppm to lower field in comparison with the acyclic
The molecular structure proves the formation of
five-membered rings which adopt an envelope confor-
mation like in 6 with angles between the two planes
C2S2 and S2Si of 33.5 and 35.3°. With an angle between
1
thiolate (BuS)2SiMe–SiMe(SBu)2 and the H- and 13C-
shifts of the methylene units are in the range found in
the five-membered rings 1, 2 and 4a–4c.
If only one equivalent of ethane-1,2-dithiol is added
to 1,1,2,2-tetrachlorodimethyldisilane in the presence of
triethylamine, a partially substituted 10 can be detected
in 56% amount besides residual 1,1,2,2-tetra-
chlorodimethyldisilane and 9a:
The NMR data are in agreement with one C2S2Si
five-membered ring and one unchanged SiCl2Me unit.
No other partially substituted products can be detected
in significant amounts (\1%). This is in strong con-
trast to the stepwise reaction of SiCl2Me–SiCl2Me with
a monodentate thiol like BuSH and shows again the
strong stabilization of five membered rings C2S2Si.
The results of the reaction of 1,1,2,2-tetra-
chlorodimethyldisilane with benzene-1,2-dithiol are
similar. The formed 11 with a bis(cyclopentyl) structure
has a 29Si-NMR chemical shift (Table 3) very close to
the value found in 9a. If only one equivalent of ben-
zene-1,2-dithiol is applied,
a partially substituted
product 12 analogous to 10 is formed, but in 67% yield
as detected by NMR spectroscopy. The 29Si-NMR
shifts of 10 and 12 are again similar. Crystals of 11
suitable for X-ray analysis could be obtained from
toluene solution. 11 crystallizes in the triclinic space
(
group P1 with two independent molecules per unit cell,
one of them is depicted in Fig. 5. The bond lengths and
angles of the two independent molecules are almost
identical. Both molecules possess a centre of symmetry
between the two silicon atoms.
Fig. 4. (a) SCHAKAL plot of the optimized structure of 9a; (b)
SCHAKAL plot of the optimized structure of 9b; (c) SCHAKAL plot of
the optimized structure of 9c.

138
U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
mm×0.25 mm, phenylmethylpolysiloxane, column tem-
perature 80°C (3 min)/20 K min−1, flow He 0.5 ml
min−1).
3.2. Crystal structure analysis
X-ray structure analysis measurements were per-
formed on a Bruker Smart CCD. Crystal data of 6, 7
and 11 as well as data collection and refinement details
are given in Table 6.
All data were corrected for absorption using SADABS
[11]. The structures were solved using direct methods
(
(
SHELX-97 [12]), refined using least-squares methods
SHELX-97) and drawn using ZORTEP [13].
Scheme 1. Differences of the calculated total energies (with zero point
correction) of the three possible isomers of Si2Me2(SCH2CH2S)2
(9a–c).
3.3. Theoretical methods
The ab initio molecular orbital calculations were
carried out using the GAUSSIAN 98 series of programs
[14]. Geometries were fully optimized at the density
functional theory level (DFT), using Becke’s three-
parameter hybrid exchange functional and the correla-
tion functional of Lee, Yang and Parr (B3LYP) [15].
Geometry optimizations, harmonic frequencies, and
zero-point vibrational energies were calculated with the
polarized 6-31G* basis set [16]. All structures were
identified as true local minima by their Hessian
matrices.
The SCHAKAL program [17] has been used for draw-
ings of the optimized structures.
Fig. 5. Molecular structure of one of the two independent molecules
of 11.
3.4. Starting materials
the two planes S2Si and SiCSi* of 89.2° there is virtu-
ally no planarization of the silicon tetrahedrons in 11.
Some important bond lengths and angles of 11 are
summarized and compared with the results of the DFT
calculations in Table 4. The calculations yield the same
conformation of 11 as global minimum, however the
calculated angles CSSi are some 4° larger resulting in
smaller envelope angles in the C2S2Si rings.
Ethane-1,2-dithiol, benzene-1,2-dithiol, triethylamine
and all used monosilanes MexSiCl4−x were commeri-
cally available. The disilanes SiClMe2–SiClMe2 [18]
and SiCl2Me–SiCl2Me [19] were prepared as described
previously.
3.5. Ethane-1,2-dithiolate deri6ati6es
3. Experimental
1.085 g (10 mmol) Me3SiCl was dissolved in 40 ml
dried hexane and 0.376 g (4 mmol) ethane-1,2-dithiol
and 0.81 g (1.1 ml, 8mmol) triethylamine were added
under stirring. After stirring overnight the mixture was
filtered from precipitated triethylammonium chloride
and the solvent was removed in vacuo yielding 0.68 g
(2.9 mmol) 1,2-bis(trimethylsilylthio)ethane 3 as an oily
residue.
3.1. NMR and GC/MS measurments
All NMR spectra were recorded on a Bruker DPX
400 in CDCl3 solution and TMS as internal standard
for 1H, 13C and 29Si. In order to obtain a sufficient
signal/noise ratio of 29Si-NMR spectra for obtaining
1JSiC satellites, 29Si INEPT spectra were also recorded.
The assignment of ipso carbon atoms in benzene-1,2-
dithiolates was simplified by recording 13C APT
spectra.
3, GC/MS: m/e (rel. int.): 238 (M+, 13), 223 (M−
Me, 18), 135 (MeSiSCH2CH2S, 14), 133 (Me3SiSCH2-
CH2, 13), 73 (Me3Si, 100).
2 was produced applying the same procedure from
MS spectra were measured on a Hewlett Packard
5971 (ionization energy 70 eV, column 30 m×0.25
0.516
g (4 mmol) Me2SiCl2, 0.376 g (4 mmol)
HSCH2CH2SH and 0.81 g (1.1 ml, 8 mmol) NEt3.

U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
139
2, GC/MS: m/e (rel. int.): 150 (M+, 52), 135 (M−
Me, 100), 109 (17), 107 (MeSiS2, 20), 101 (12), 75
(SSiMe, 29).
Solid 1 was obtained from 0.34 g (2 mmol) SiCl4,
0.376 g (4 mmol) HSCH2CH2SH and 0.81 g (1.1 ml, 8
30), 63 (SiCl, 39) (isotope patterns are in accordance
with one 35/37Cl).
8 was produced by addition of 0.188 g (2 mmol)
HSCH2CH2SH and 0.405 g (0.55 ml, 4 mmol) NEt3 to
a solution of 0.374 g (2 mmol) SiClMe2–SiClMe2 in
40 ml hexane after filtration from precipitated
HNEt3Cl and removal of the solvent in vacuo, m.p.
23–24°C [10].
mmol) NEt3. Starting from
a
molar ratio
SiCl4:HSCH2CH2SH:NEt3=1:1:2 again pure 1 was
produced without the formation of any partially substi-
tuted products.
8, GC/MS: m/e (rel. int.): 208 (M+, 7), 180 (S2Si2Me4,
5), 165 (Me3SiSCH2CH2S, 100), 135 (MeSiSCH2CH2S,
5), 90 (Me2SiS, 7), 75 (MeSiS, 22), 73 (Me3Si, 42)
9a resulted from the analogous reaction of 0.228 g (1
mmol) SiCl2Me–SiCl2Me with 0.188 g (2 mmol)
HSCH2CH2SH and 0.405 g (0.55 ml, 4 mmol) NEt3 in
hexane solution, m.p. 99°C, elemental analysis
(C6H14S4Si2, calc., found): C: 26.63, 26.27; H: 5.22, 4.91;
S: 47.39, 48.01%.
The reaction of 0.30 g (2 mmol) MeSiCl3 with 0.188
g (2 mmol) HSCH2CH2SH and 0.405 g (0.55 ml, 4
mmol) NEt3 (molar ratio: 1:1:2) yielded an oily mixture
consisting of 64% 4a besides 18% 4b and 18% 4c.
Repetition of the same reaction with 0.30 g (2 mmol)
MeSiCl3, 0.282 g (3 mmol) HSCH2CH2SH and 0.61 g
(0.83 ml, 6 mmol) NEt3 (molar ratio 1:1.5:3) resulted in
the formation of a mixture of 80% 4a plus 20% 4c.
4b, GC/MS: m/e (rel. int.): 170 (M+, 75), 155 (M−
Me, 100), 142 (S2SiClMe, 10), 129 (13), 111 (HSSiClMe,
10 was obtained in mixture with 9a and starting
SiCl2Me–SiCl2Me by treatment of a solution of 0.228 g
Table 6
Crystal data of 6, 7 and 11 as well as data collection and refinement details
6
7
11
Crystal system
Space group
Unit cell dimensions
Orthorhombic
Pna21
Monoclinic
C2/c
Triclinic
(
P1
,
a (A)
10.1583(1)
9.8387(2)
9.9861(1)
90
90
90
998.06(2); 4
1.320
0.590
14.7059(3)
11.0980(3)
8.0920(3)
90
102.322(1)
90
1290.24(6); 4
1.588
0.800
8.1987(3)
10.6739(3)
10.9473(3)
112.606(1)
106.157(2)
91.006(1)
841.07(5); 2
1.448
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
Volume (A ); Z
Density (calculated) (g cm−3
)
linear absorption coefficient (mm−1
Radiation used
)
0.694
Mo–Ka
Temperature (K)
173(2)
Scan method
ꢀ scans
Empirical
0.70882/0.55396
7417
2592
2430
Absortion correction
Maximum/minimum transmission
Measured reflections
Independent reflections
Observed reflections
Rint
0.78637/0.48172
4345
0.91826/0.63945
6490
1708
4318
1380
2126
0.0306
0.0535
0.0573
q range for collection (°)
Completeness to qmax (%)
Refinement method
final R (I\2|(I))
2.88–30.54
94.0
2.32–30.13
89.2
2.09–30.14
86.9
Full-matrix least-squares on F2
R1: 0.0242
R1: 0.0271
difmap/refall
1.036
R1: 0.0305
R1: 0.0466
R1: 0.0617
R1: 0.1588
R (all data)
H locating and refining
Goodness-of-fit on F2
1.084
0.706/−0.653
0.959
0.613/−0.469
−3
,
Maximum/minimum e-density (e A
)
0.266/−0.185
SMART
Data collection program
Cell refinement program
Data reduction program
Absorption correction
Structure solving program
Structure refining program
Structure drawing
SAINT
XPREP
SADABS
SHELXS-97
SHELXL-97
ZORTEP

140
U. Herzog et al. / Journal of Organometallic Chemistry 612 (2000) 133–140
(1 mmol) SiCl2Me–SiCl2Me in 40 ml hexane with 0.094
g (1 mmol) HSCH2CH2SH and 0.20 g (0.28 ml, 2
mmol) NEt3. An attempt was made to separate 10 from
9a by fractional distillation: the product of the reaction
of 12.5 g (55 mmol) SiCl2Me–SiCl2Me with 4.7 g (50
mmol) HSCH2CH2SH and 10.1 g (13.8 ml, 100 mmol)
NEt3 in 150 ml hexane yielded after filtration and
removal of the solvent 2.6 g of a fraction at 120–
130°C/0.6 kPa. The 29Si-NMR spectrum (obtained after
2 days) revealed that the product was again equilibrated
to a mixture of 63% 10, 18% 9a and 13% SiCl2Me–
SiCl2Me. Besides these disilanes also 5% 4b and 1% 1
were observed as decomposition products formed dur-
ing the distillation.
supplementary publication nos. CCDC 145927 for 6,
CCDC 145928 for 7, CCDC: 145929 for 11. Copies of
the data can be obtained free of charge on application
to The Director, CCDC, 12 Union Road, Cambridge
CB2 1EZ, UK (Fax: +44-1223-336033; e-mail:
deposit@ccdc.cam.ac.uk or www: http://www.ccdc.cam.
ac.uk).
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3.6. Benzene-1,2-dithiolate deri6ati6es
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hexane and 0.12 g (0.85 mmol) o-C6H4(SH)2 and 0.20 g
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Similar reaction of 0.129 g (1 mmol) Me2SiCl2 with
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0.30 g (0.97 mmol) 7 (m.p.\190°C, dec.) were ob-
tained by the reaction of 0.191 g (1.125 mmol) SiCl4
with 0.32 g (2.25 mmol) o-C6H4(SH)2 and 0.45 g (0.63
ml, 4.5 mmol) NEt3 in 20 ml toluene after filtration and
removal of the solvent.
The reaction of 0.281 g (1.5 mmol) SiClMe2–
SiClMe2 with 0.213 g (1.5 mmol) o-C6H4(SH)2 and 0.30
g (0.42 ml, 3 mmol) NEt3 in 20 ml toluene resulted after
filtration and removal of the solvent in an oily product
whose NMR spectra suggested the formation of HS(o-
C6H4)S(SiMe2)2S(o-C6H4)SH (lSi: 3.9 ppm) as main
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compound o-C6H4(SSiMe2)2.
Finally the addition of 0.213 g (1.5 mmol) o-
C6H4(SH)2 and 0.30 g (0.42 ml, 3 mmol) NEt3 to a
solution of 0.171 g (0.75 mmol) SiCl2Me–SiCl2Me in 20
ml toluene resulted in the formation of 0.24 g (0.67
mmol) 11 (m.p. 115°C).
12 was obtained in mixture with SiCl2Me–SiCl2Me
and 11 by a repetition of this reaction with twice the
amount of SiCl2Me–SiCl2Me.
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4. Supplementary material
Crystallographic data (excluding structure factors)
for the structures in this paper have been deposited
with the Cambridge Crystallographic Data Centre as
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.