3,7,10-Trichalcogenaoctasila[3.3.3]propellanes

Article abstract of DOI:10.1002/1099-0682(200112)2001:12<3107::AID-EJIC3107>3.0.CO;2-E

The reaction of hexakis(trimethylsilyl)disilane with acetyl chloride and aluminum chloride yields hexakis(chlorodimethylsilyl)disilane (5a) under carefully controlled reaction conditions. Treatment of 5a with either H₂S/NEt₃ or Li₂E (E = Se, Te) gives the dodecamethyl-3,7,10-trichalcogenaoctasila[3.3.3]propellanes Si₂(SiMe₂)₆E₃ (6a E = S, 6b E = Se, 6c E = Te). The products have been characterized by multinuclear NMR spectroscopy (¹H, ¹³C, ²⁹Si, ⁷⁷Se, ¹²⁵Te). The central silicon atoms are very deshielded in comparison with other compounds containing an Si(Si)₄ unit due to their incorporation into three five-membered rings. The molecular structures of 5a and 6a are reported revealing an elongated central Si-Si bond in 5a of 2.3865(11) A and three different spatial orientations of the SiMe₂Cl groups in each Si(SiMe₂Cl)₃ unit. In 6a all three five-membered rings Si₄S adopt envelope conformations with the four silicon atoms in one plane. A view of the Si₈S₃ skeleton along the central silicon-silicon bond of 6a resembles a three-blade propeller.

Full text of DOI:10.1002/1099-0682(200112)2001:12<3107::AID-EJIC3107>3.0.CO;2-E

FULL PAPER
3,7,10-Trichalcogenaoctasila[3.3.3]propellanes
U. Herzog*[a] and G. Rheinwald[b]
Keywords: Silanes / Sulfur / Selenium / Tellurium / Polycycles
The reaction of hexakis(trimethylsilyl)disilane with acetyl
compounds containing an Si(Si)4 unit due to their incorpora-
chloride and aluminum chloride yields hexakis(chlorodime- tion into three five-membered rings. The molecular struc-
thylsilyl)disilane (5a) under carefully controlled reaction con- tures of 5a and 6a are reported revealing an elongated cent-
ditions. Treatment of 5a with either H2S/NEt3 or Li2E (E = Se, ral Si−Si bond in 5a of 2.3865(11) A and three different spatial
˚
Te) gives the dodecamethyl-3,7,10-trichalcogenaoctasila-
[3.3.3]propellanes Si2(SiMe2)6E3 (6a E = S, 6b E = Se, 6c E =
Te). The products have been characterized by multinuclear
NMR spectroscopy (1H, 13C, 29Si, 77Se, 125Te). The central sil-
orientations of the SiMe2Cl groups in each Si(SiMe2Cl)3 unit.
In 6a all three five-membered rings Si4S adopt envelope con-
formations with the four silicon atoms in one plane. A view
of the Si8S3 skeleton along the central silicon−silicon bond of
icon atoms are very deshielded in comparison with other 6a resembles a three-blade propeller.
Introduction
In previous investigations we have shown that the reac-
tion of 1,1,2,2-tetrakis(chlorodimethylsilyl)dimethyldisilane
(1) with either H2S/NEt3 or Li2E (E ϭ Se, Te) yields exclu-
sively the 3,7-dichalcogenahexasilabicyclo[3.3.0]octanes
[2aϪc; Equation (1)].[1]
(1)
Scheme 1
Results and Discussion
The formation of these compounds underlines the gen-
eral observation that the formation of five-membered heter-
Formation and Structure of
Hexakis(chlorodimethylsilyl)disilane (5a)
ocycles is preferred in the systems silicon-sulfur, -selenium
and -tellurium.[2,3] The facile formation of the bicyclic sys-
The formation of 3,7,10-trichalcogenaoctasila[3.3.3]pro-
tems tempted us to apply these reactions to the synthesis
of the corresponding tricyclic ring systems, which can be
described as [3.3.3]propellanes (3a, Scheme 1).
It should be mentioned that carbon-based [3.3.3]pro-
pellanes have been known for some time[4,5] and even a nat-
urally occurring sesquiterpene, modhephene (3b),[6,7] con-
taining this tricyclic skeleton has been described. Molecular
structures have been reported for modhephenediol (3c,
2,3-dihydroxy-2,4,4,8-tetramethyl[3.3.3]propellane,[6]) and
[3.3.3]-propellane-2,8,9-trione (3d).[8]
pellanes requires an octasilane skeleton with six chlorodi-
methylsilyl units connected to a central disilane. This com-
pound, hexakis(chlorodimethylsilyl)disilane (5a), can be
prepared in three steps starting from tetrakis(trimethylsilyl)-
silane by the formation of hypersilylpotassium developed
by Marschner[9] [Equation (2)] and a subsequent oxidative
dimerization of the hypersilanyl anion [Equation (3)].
(2)
(3)
[a]
Institut für Anorganische Chemie der TU Bergakademie
Freiberg,
Leipziger Str. 29, 09596 Freiberg, Germany
[b]
Institut für Chemie, Lehrstuhl Anorganische Chemie,
TU Chemnitz,
Straße der Nationen 62, 09111 Chemnitz, Germany
Eur. J. Inorg. Chem. 2001, 3107Ϫ3112
WILEY-VCH Verlag GmbH, 69451 Weinheim, 2001
1434Ϫ1948/01/1212Ϫ3107 $ 17.50ϩ.50/0
3107

U. Herzog, G. Rheinwald
FULL PAPER
(4)
The molecular structure of the formed hexakis(trimethyl- reduces the steric overcrowding resulting in a slightly
silyl)disilane (4) has been reported previously[10,11] revealing shorter central SiϪSi bond than in 4. A closer look re-
˚
an elongated central SiϪSi bond of 2.40 A.
veals that in each Si(SiMe2Cl)3 unit there are three differ-
The treatment of 4 with acetyl chloride and aluminum ent SiMe2Cl groups which can be distinguished by their
chloride in hexane yields the desired hexachlorinated octasi- different dihedral angles ClϪSiϪSiϪSi (see Table 1). A
lane 5a under optimized reaction conditions. Slightly higher comparison of the two Si(SiMe2Cl)3 units shows that the
reaction temperatures also led to the formation of the silyl units containing Si(2) and Si(8) have a similar ori-
higher chlorinated octasilanes 5b and 5c [Equation (4)].
entation, as is the case for Si(3) and Si(7) and Si(4) and
The molecular structure of 5a is shown in Figure 1 and Si(6). A look at the SiϪSiϪSi angles shows that all the
2 and selected bond lengths and angles are summarized SiϪSi(1)ϪSi(5) ands Si(1)ϪSi(5)ϪSi angles are larger than
in Table 1. The structure of 5a is a rare example of a the tetrahedral angle of 109.5°, while all the SiϪSiϪSi
successful crystal structure determination of a methylchlo- angles within each Si(SiMe2Cl)3 unit are smaller. This is
rooligosilane because most compounds of this class are a result of the mutual repulsion of the two Si(SiMe2Cl)3
liquids or low melting solids which are highly soluble in units connected by the central SiϪSi bond. By comparing
all organic solvents. The central siliconϪsilicon bond of the angles CϪSiϪC (107.93Ϫ112.18°, average 109.68°)
˚
5a (Si1ϪSi5) is, at 2.3865(11) A, longer than the other and CϪSiϪSi (112.18Ϫ117.41°, average 114.30°) with the
SiϪSi bonds but slightly shorter than that in 4. In both angles CϪSiϪCl (104.94Ϫ107.03°, average 106.00°) and
Si(SiMe2Cl)3 units one chlorine substituent occupies a ClϪSiϪSi (102.97Ϫ109.18°, average 105.68°) it can be
more axial position with respect to the central SiϪSi clearly seen that a methyl group occupies more space
bond (Cl3, Cl4) while the other two are equatorial. This than a chlorine substituent.
Figure 1. Molecular structure of 5a
Figure 2. Molecular structure of 5a viewed along the Si1ϪSi5 bond
Eur. J. Inorg. Chem. 2001, 3107Ϫ3112
3108

3,7,10-Trichalcogenaoctasila[3.3.3]propellanes
FULL PAPER
˚
Table 1. Selected bond lengths (A) and angles (°) of 5a
Table 2. 29Si, 77Se, 125Te, 13C and 1H NMR spectroscopic data
(ppm, Hz) of the [3.3.3]propellanes Si2(SiMe2)6E3 (E ϭ S, Se, Te)
Atoms
Distances Atoms
Angles
Si(1)ϪSi(2)
Si(1)ϪSi(3)
Si(1)ϪSi(4)
Si(1)ϪSi(5)
Si(5)ϪSi(6)
Si(5)ϪSi(7)
Si(5)ϪSi(8)
2.3754(11) Si(2)ϪSi(1)ϪSi(3)
2.3597(12) Si(2)ϪSi(1)ϪSi(4)
2.3597(10) Si(3)ϪSi(1)ϪSi(4)
2.3865(11) Si(2)ϪSi(1)ϪSi(5)
2.3658(10) Si(3)ϪSi(1)ϪSi(5)
2.3676(11) Si(4)ϪSi(1)ϪSi(5)
2.3617(12) Si(6)ϪSi(5)ϪSi(1)
104.64(4)
104.27(4)
105.31(4)
117.20(4)
110.48(4)
113.88(4)
116.16(4)
112.14(4)
112.50(4)
105.57(4)
104.09(4)
105.45(4)
109.18(5)
104.78(5)
103.21(4)
102.97(5)
106.98(5)
106.97(5)
Si(2)ϪCl(1) 2.0621(12) Si(7)ϪSi(5)ϪSi(1)
Si(3)ϪCl(2) 2.0911(11) Si(8)ϪSi(5)ϪSi(1)
Si(4)ϪCl(3) 2.0865(11) Si(6)ϪSi(5)ϪSi(7)
Si(6)ϪCl(4) 2.1002(12) Si(6)ϪSi(5)ϪSi(8)
Si(7)ϪCl(5) 2.0778(11) Si(7)ϪSi(5)ϪSi(8)
Si(8)ϪCl(6) 2.0764(12) Si(1)ϪSi(2)ϪCl(1)
Si(2)ϪC(1)
Si(2)ϪC(2)
Si(3)ϪC(3)
Si(3)ϪC(4)
Si(4)ϪC(5)
Si(4)ϪC(6)
Si(6)ϪC(7)
Si(6)ϪC(8)
Si(7)ϪC(9)
1.883(3)
1.879(3)
1.857(4)
1.854(4)
1.849(4)
1.885(3)
1.849(4)
1.867(4)
1.856(4)
Si(1)ϪSi(3)ϪCl(2)
Si(1)ϪSi(4)ϪCl(3)
Si(5)ϪSi(6)ϪCl(4)
Si(5)ϪSi(7)ϪCl(5)
Si(5)ϪSi(8)ϪCl(6)
Si(4)ϪSi(1)ϪSi(5)ϪSi(6) Ϫ157.81(5)
Si(3)ϪSi(1)ϪSi(5)ϪSi(7) 81.97(5)
Si(2)ϪSi(1)ϪSi(5)ϪSi(8) Ϫ39.67(5)
Si(5)ϪSi(1)ϪSi(2)ϪCl(1) Ϫ31.78(6)
Si(5)ϪSi(1)ϪSi(3)ϪCl(2) 68.92(5)
Si(5)ϪSi(1)ϪSi(4)ϪCl(3) Ϫ174.49(5)
Si(1)ϪSi(5)ϪSi(8)ϪCl(6) Ϫ33.29(6)
Si(1)ϪSi(5)ϪSi(7)ϪCl(5) 68.48(6)
Si(1)ϪSi(5)ϪSi(6)ϪCl(4) Ϫ167.52(5)
Si(7)ϪC(10) 1.882(3)
Si(8)ϪC(11) 1.870(3)
Si(8)ϪC(12) 1.861(3)
(4, δSi ϭ Ϫ129.5[9]) or even chloro-substituted derivatives
like Si(SiMe2Cl)4 (δSi ϭ Ϫ113.9[14]) and Si2(SiMe2Cl)6 (5a,
3,7,10-Trichalcogenaoctasila[3.3.3]propellanes
δ
Si ϭ Ϫ111.62) the chemical shifts found in the propellanes
The reaction of 5a with either H2S/NEt3 in hexane or
Li2E (E ϭ Se, Te) prepared in situ from the chalcogens and
LiBEt3H in THF yielded the expected dodecamethyl-
3,7,10-trichalcogenaoctasila[3.3.3]propellanes 6aϪc [Equa-
tion (5) and (6)]:
6aϪc are shifted significantly to lower field, especially in
the cases of the heavier chalcogens (Se, Te; see Figure 3).
(5)
(6)
Figure 3. 29Si NMR chemical shifts in bicyclo[3.3.0]octanes (2aϪc)
[1] and [3.3.3]propellanes (6aϪc) for E ϭ S, Se, Te
The NMR spectroscopic data of the propellanes 6aϪc
It has been observed before that the formation of five-
are given in Table 2. While the δSi values of the SiMe2 units membered rings in the silicon chalcogen systems is always
are similar to those in the corresponding monocyclic five- accompanied by a strong low-field shift of the 29Si NMR
membered rings (SiMe2)4E[12] and the bicyclo[3.3.0]octanes signals, which increases from sulfur to tellurium in the case
2aϪc, the NMR chemical shifts of the central Si atoms are of oligosilanyl units.[3] In the cases of the central silicon
remarkable. Compared with other compounds containing atoms in the propellanes 6aϪc these atoms are incorporated
Si(Si)4 units like Si(SiMe3)4 (δSi ϭ Ϫ135.5[13]), Si2(SiMe3)6 into three five-membered rings causing these unusual low-
Eur. J. Inorg. Chem. 2001, 3107Ϫ3112
3109

U. Herzog, G. Rheinwald
FULL PAPER
field shifts. Furthermore, compared to the bicyclo[3.3.0]oc- ideal envelope conformations with dihedral angles
tanes 2bϪc[1] the 77Se and the 125Te NMR signals of the SiϪSi(1)ϪSi(5)ϪSi of Ϫ4.8 to Ϫ5.2° and envelope angles
propellanes 6bϪc are shifted to lower field by 89 ppm (Se) of 44.57(6)° [Si4S ring including S(1)], 46.52(6)° [Si4S ring
and 114 ppm (Te), despite the same first and second coor- including S(2)] and 45.28(8)° [Si4S ring including S(3)]. This
dination sphere around the chalcogen atoms.
is slightly more than in the organic [3.3.3]propellane
Compound 6a was characterized by its mass spectrum modhephenediol (3c) with envelope angles of 37Ϫ42°[6] and
and also by an X-ray structure analysis. Figure 4 shows the close to the envelope angles in the bicyclo[3.3.0]octane de-
molecular structure of 6, and some bond lengths and angles rivative 2a [42.34(4)° and 44.35(3)° [1]]. In contrast to the
are given in Table 3.
structure of 2a, however, all three five-membered rings in
In contrast to 5a all the SiϪSi bond lengths are in the 6a are folded in the same rotatory sense resembling an al-
usual range. All three five-membered rings adopt almost most ideal three-blade propeller (Figure 5). The angles at
the sulfur atoms in 6a are, at 101.5Ϫ102.4°, close to the
values in 2a. The same holds for the SiϪSi and the SiϪS
bond lengths. Due to the formation of the five-membered
rings all SiϪSiϪSi angles including the Si(1)ϪSi(5) bond
are smaller than the tetrahedral angle (101.5Ϫ102.6°) re-
sulting in SiϪSiϪSi angles of more than 109.5° within the
Si3Si(1) and Si3Si(5) units (in the range of 115.1Ϫ116.4°).
Figure 4. Molecular structure of 6a
Figure 5. The silicon and sulfur skeleton of 6a viewed along the
central SiϪSi bond
˚
Table 3. Selected bond and distances (A) and angles (°) of 6a
Atoms
Distances
Atoms
Angles
Experimental Section
Si(1)ϪSi(2)
Si(1)ϪSi(3)
Si(1)ϪSi(4)
Si(1)ϪSi(5)
Si(5)ϪSi(6)
Si(5)ϪSi(7)
Si(5)ϪSi(8)
Si(2)ϪS(1)
Si(3)ϪS(2)
Si(4)ϪS(3)
Si(6)ϪS(1)
Si(7)ϪS(2)
Si(8)ϪS(3)
Si(2)ϪC(1)
Si(2)ϪC(2)
Si(3)ϪC(3)
Si(3)ϪC(4)
Si(4)ϪC(5)
Si(4)ϪC(6)
Si(6)ϪC(7)
Si(6)ϪC(8)
Si(7)ϪC(9)
2.3564(17) Si(2)ϪS(1)ϪSi(6)
2.3543(15) Si(3)ϪS(2)ϪSi(7)
2.3621(17) Si(4)ϪS(3)ϪSi(8)
2.3487(16) Si(2)ϪSi(1)ϪSi(3)
2.3416(15) Si(2)ϪSi(1)ϪSi(4)
2.3416(16) Si(3)ϪSi(1)ϪSi(4)
2.3395(17) Si(2)ϪSi(1)ϪSi(5)
2.1501(18) Si(3)ϪSi(1)ϪSi(5)
2.1541(18) Si(4)ϪSi(1)ϪSi(5)
2.1492(16) Si(6)ϪSi(5)ϪSi(1)
2.1479(18) Si(7)ϪSi(5)ϪSi(1)
2.1543(15) Si(8)ϪSi(5)ϪSi(1)
2.1401(18) Si(6)ϪSi(5)ϪSi(7)
102.40(7)
101.53(6)
101.65(7)
115.41(7)
116.39(7)
115.24(6)
101.89(6)
102.60(6)
102.02(6)
102.58(6)
101.55(6)
101.80(6)
115.15(6)
116.37(6)
115.91(6)
106.34(7)
105.49(6)
106.15(7)
104.89(6)
104.80(6)
105.50(7)
General: All NMR spectra were recorded on a Bruker DPX 400 in
CDCl3 solution and TMS as internal standard for 1H, 13C and 29Si.
External Ph2Se2 (δSe ϭ 460) and Ph2Te2 (δTe ϭ 422) in CDCl3 were
used as standards for 77Se and 125Te. In order to obtain a sufficient
signal-to-noise ratio of 29Si NMR spectra for obtaining 1JSiC, 1JSiSi
,
1,2,3
1
J
or JSiTe satellites 29Si INEPT spectra were also recorded.
SiSe
77Se and 125Te spectra were determined using an IGATED pulse
program.
Mass spectra were measured on a Hewlett Packard 5971 (ionization
energy: 70 eV, column: 30 m ϫ 0.25 mm ϫ 0.25 µm, phenylmethyl-
polysiloxane, column temperature: 80 °C (3 min)/20 K/min, flow:
He 0.5 mL/min).
1.871(5)
1.854(5)
1.856(5)
1.868(4)
1.864(4)
1.861(5)
1.855(4)
1.868(5)
1.860(4)
Si(6)ϪSi(5)ϪSi(8)
Si(7)ϪSi(5)ϪSi(8)
Si(1)ϪSi(2)ϪS(1)
Si(1)ϪSi(3)ϪS(2)
Si(1)ϪSi(4)ϪS(3)
Si(5)ϪSi(6)ϪS(1)
Si(5)ϪSi(7)ϪS(2)
Si(5)ϪSi(8)ϪCl(6)
Starting Materials: H2S (N25, Air Liquide), Se, Te, triethylamine,
1  LiBEt3H in THF (Super Hydride), were commercially available.
Si(SiMe3)4 was prepared as described in ref.[21] THF was distilled
from sodium/potassium alloy prior to use. The other solvents were
dried over KOH or sodium wire. All reactions were carried out
under argon using standard Schlenk techniques.
Si(4)ϪSi(1)ϪSi(5)ϪSi(8) Ϫ4.95(7)
Si(3)ϪSi(1)ϪSi(5)ϪSi(7) Ϫ5.21(8)
Si(2)ϪSi(1)ϪSi(5)ϪSi(8) Ϫ4.79(7)
Si(7)ϪC(10) 1.865(4)
Si(8)ϪC(11) 1.867(4)
Si(8)ϪC(12) 1.868(4)
Crystal Structure Analysis: X-ray structure analysis measurements
were performed on a Bruker SMART CCD. Crystal data of 5a and
3110
Eur. J. Inorg. Chem. 2001, 3107Ϫ3112

3,7,10-Trichalcogenaoctasila[3.3.3]propellanes
FULL PAPER
Table 4. Crystal data of 5a and 6a as well as data collection and refinement details
5a
6a
Chemical formula
Molecular weight
Crystal system
Space group
C12 H36 Cl6 Si8
617.83
monoclinic
P21/n
a ϭ 10.9820(6)
b ϭ 17.0125(10)
c ϭ 17.2780(11)
β ϭ 100.401(2)
3175.0(3); 4
1.292
C12 H36 S3 Si8
501.31
monoclinic
C2/c
a ϭ 14.6972(19)
b ϭ 12.0174(14)
c ϭ 31.930(4)
β ϭ 100.812(2)
5539.4(12); 8
1.202
˚
Unit cell dimensions, A, °
3
˚
Volume in A ; Z
Density (calcd.) in g/cm3
Linear absorption coeff., mmϪ1
Radiation used
0.845
Mo-Kα
0.612
Mo-Kα
Temperature
Scan method
173(2) K
ω scans
173(2) K
ω scans
Absorption correction
Max./min. transmission
Measured reflections
Independent reflections
Observed reflections
Index range
empirical
0.9202/0.6773
14079
6291
4435
Ϫ13 Յ h Յ 12
Ϫ23 Յ k Յ 4
Ϫ22 Յ l Յ 22
0.0341
empirical
0.9138/0.8144
12037
6510
3151
Ϫ19 Յ h Յ 19
Ϫ16 Յ k Յ 8
Ϫ15 Յ l Յ 42
0.0713
R(int)
θ range for collection, °
1.69Ϫ29.36
72.1
1.30Ϫ29.47
84.6
Completeness to θmax
%
Refinement method
full-matrix least-squares on F2
0.0368/0.0900
0.0643/0.1008
6291/379
full-matrix least-squares on F2
0.0532/0.1030
0.1493/0.1279
6510/220
Final R1/wR2 [I Ͼ 2 σ(I)][a]
[a]
R1/wR2 (all data)
No. of reflections/parameters used
H-locating and refining
difmap/refall
1.000
0.472/-0.410
geom./constr.
0.904
0.545/-0.421
Goodness-of-fit (S)[b] on F2
3
˚
Max./min. e-density in e/A
[a]
2
2 2
4
2
2
2
R1 ϭ Σ(||Fo| Ϫ |Fc||)/Σ|Fo|, wR2 ϭ [Σ[w(Fo Ϫ Fc ) ]/Σ(wFo )]1/2, w ϭ 1/[σ2(Fo ) ϩ (aP)2 ϩ bP] where P ϭ (Fo ϩ 2Fc )/3, a ϭ 0.0530,
b ϭ 0.5866 (5a), a ϭ 0.053, b ϭ 0 (6a). Ϫ S ϭ [Σw(Fo Ϫ Fc ) ]/(n Ϫ p)1/2, n ϭ number of reflections, p ϭ parameters used.
[b]
2
2 2
6a as well as data collection and refinement details are given in vacuo at 130 °C for 6 h. The residue of the sublimation was almost
Table 4. The unit cell dimensions were determined with the pro-
gram SMART.[15] The program SAINT[15] was used for data integ-
ration and refinement of the unit cell parameters. The space group
pure 4 in 72% yield, which could be used without further purifica-
1
tion. H NMR: δ ϭ 0.274; 13C NMR: δ ϭ 4.38 (1JSiC ϭ 42.3 Hz);
1
29Si NMR: δ ϭ Ϫ9.55 (SiMe3, JSiSi ϭ 53.0 Hz), Ϫ130.13 (SiSi4).
was determined with the aid of the programs ABSEN[16] (5a) and Ϫ GC/MS: m/z (%) ϭ 494 (4) [Mϩ], 479 (4) [M Ϫ Me], 421 (3)
XPREP[15] (6a). All data were corrected for absorption using SAD-
[Me15Si7], 406 (5) [Me14Si7], 305 (2) [Me11Si5], 273 (11) [Me7Si6],
247 (22) [Me9Si4], 232 (100) [Me8Si4], 199 (15), 173 (12)
ABS.[17] The structures were solved using direct methods [SIR97[18]
(5a), SHELX97[19] (6a)], refined using least-squares methods [Me5Si3CH2], 131 (13) [Me5Si2], 73 (62) [Me3Si].
(SHELX-97) and drawn using Diamond.[20] The ellipsoids of the
non-hydrogen atoms are at the 50% probability level. The hydrogen
atoms on the methyl groups in 6a were refined as constrained
groups, whereas all hydrogen atoms in 5a could be located from
the difference map and fully refined.
Crystallographic data (excluding structure factors) for the struc-
tures in this paper have been deposited with the Cambridge Crys-
Hexakis(chlorodimethylsilyl)disilane, Si2(SiMe2Cl)6 (5a): Com-
pound 4 (1.36 g, 2.75 mmol) was dissolved in 20 mL hexane and
anhydrous aluminum chloride (3.00 g, 22.5 mmol) was added.
Acetyl chloride (1.6 g, 20 mmol) was slowly added to this stirred
mixture. After stirring overnight the reaction mixture was heated
to 40 °C for one hour and the hexane phase was separated. Re-
tallographic Data Centre as supplementary publication nos. moval of the solvent in vacuo yielded 0.70 g (1.13 mmol, 41%) of
1
CCDC-164379 (5a) and -164380 (6a). Copies of the data can be
pure crystalline 5a, m.p.: 257 °C; H NMR: δ ϭ 0.845; 13C NMR:
obtained, free of charge, on application to CCDC, 12 Union Road, δ ϭ 8.05 (1JSiC ϭ 48.7 Hz); 29Si NMR: δ ϭ 29.06 (SiMe2Cl, 1JSiSi ϭ
Cambridge CB2 1EZ, UK [Fax: (internat.) ϩ44-1223/336-033, 56.9 Hz), Ϫ111.62 (SiSi4). Ϫ GC/MS: m/z (%) ϭ 601 (2) [M Ϫ
E-mail: deposit@ccdc.cam.ac.uk].
Me], 581 (1) [M Ϫ Cl], 523 (44) [Me10Cl5Si7], 488 (21) [Me10Cl4Si7],
395 (9) [Me8Cl3Si6], 380 (15) [Me7Cl3Si6], 309 (13) [Me6Cl3Si4], 272
(42) [Me6Cl2Si4], 209 (18) [Me6ClSi3], 174 (13) [Me6Si3], 131 (26)
[Me5Si2], 93 (37) [Me2ClSi], 73 (100) [Me3Si].
Hexakis(trimethylsilyl)disilane, Si2(SiMe3)6 (4): Si(SiMe3)4 was re-
acted in THF with KOtBu and the resulting KSi(Me3Si)3 solution
was treated with C2H4Br2 as described in ref.[9] After removal of
the solvent the product was a mixture of 4 and approximately 25%
Si(SiMe3)4. The two compounds were separated by sublimation in
If the reaction mixture was heated to 70 °C, a mixture of 5a (52%),
(ClMe2Si)3SiϪSi
(SiClMe2)2(SiCl2Me)
(5b;
43%)
and
Eur. J. Inorg. Chem. 2001, 3107Ϫ3112
3111

U. Herzog, G. Rheinwald
(Cl2MeSiC)(ClMe2SiB)2SiAϪSiA(SiBClMe2)2(SiCCl2Me) (5c; 5%) of Inorganic Chemistry, TU Chemnitz for the access to the X-ray
FULL PAPER
was obtained after removal of the solvent hexane.
facility used to determine the single crystal structures.
(ClMe2SiC)3SiA؊SiB(SiDClMe2)2(SiECl2Me) (5b): 13C NMR: δ ϭ
8.03 (SiCMe2), 7.69 (SiDMe2), 13.02 (SiEMe); 29Si NMR: δ ϭ
Ϫ111.23 (SiA), Ϫ104.08 (SiB), 28.88 (SiC), 27.85 (SiD), 36.98 (SiE).
Ϫ GC/MS: m/z (%) ϭ 623 (2) [M Ϫ Me], 543 (27) [Me9Cl6Si7], 508
(28) [Me9Cl5Si7], 415 (10) [Me7Cl4Si6], 400 (24) [Me6Cl4Si6], 309
(31) [Me6Cl3Si4], 272 (13) [Me6Cl2Si4], 209 (19) [Me6ClSi3], 159 (22)
[Me5Si3], 131 (29) [Me5Si2], 93 (61) [Me2ClSi], 73 (100) [Me3Si].
[1]
U. Herzog, U. Böhme, E. Brendler, G. Rheinwald, J. Or-
ganomet. Chem. 2001, 630, 139Ϫ148.
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Organomet. Chem. 2000, 602, 193Ϫ207.
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10867Ϫ10878.
L. H. Zalkow, R. N. Harris III, D. van Derveer, J. Chem. Soc.,
Chem. Commun. 1978, 420Ϫ421.
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29, 5525Ϫ5528.
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C. Marschner, Eur. J. Inorg. Chem. 1998, 221Ϫ226.
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413Ϫ415; Angew. Chem. Int. Ed. Engl. 1993, 32, 414Ϫ416.
F. R. Fronczek, P. D. Lickiss, Acta Crystallogr., Sect. C 1993,
49, 331Ϫ333.
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29Ϫ32.
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339, 637Ϫ641.
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P. McArdle, J. Appl. Cryst. 1996, 29, 306.
G. M. Sheldrick, SADABS V2.01, Program for Empirical Ab-
sorption Correction of Area Detector Data, University of
Göttingen, Germany, 2000.
A. Altomare, M. C. Burla, M. Camalli, G. L. Cascarano, C.
Giacovazzo, A. Guagliardi, A. G. G. Moliterni, G. Polidori, R.
[2]
[3]
[4]
(Cl2MeSiC)(ClMe2SiB)2SiA؊SiA(SiBClMe2)2(SiCCl2Me) (5c): 29Si
NMR: δ ϭ Ϫ111.23 (SiA), 27.75 (SiB), 36.21 (SiC).
[5]
Dodecamethyl-3,7,10-trithiaoctasila[3.3.3]propellane, Si2(SiMe2)6S3
(6a): Compound 5a (0.23 g, 0.37 mmol) was dissolved in 30 mL
hexane and NEt3 (0.35 mL, 2.5 mmol) was added while a stream of
dried H2S was bubbled through the stirred solution. After stirring
overnight the reaction mixture was filtered. Removal of the solvent
from the filtrate yielded 0.14 g (0.28 mmol, 76%) of pure 6a as a
colorless crystalline residue. Single crystals of 6a were grown from
a solution in hexane, m.p.: 225 °C (decomp.).
[6]
[7]
[8]
[9]
[10]
[11]
6a: GC/MS: m/z (%) ϭ 500 (25) [Mϩ], 485 (6) [M Ϫ Me], 441
(8) [Me9Si7S3CH2], 427 (29) [Me9Si7S3], 395 (3) [Me9Si7S2], 351 (6)
[Me7Si6S2CH2], 337 (7) [Me7Si6S2], 293 (6) [Me5Si5S2CH2], 277 (10)
[Me7Si5S], 262 (8) [Me6Si5S], 247 (15) [Me5Si5S], 233 (11) [Me5-
Si4SCH2], 189 (11) [Me7Si3], 131 (13) [Me5Si2], 73 (100) [Me3Si].
[12]
[13]
[14]
Dodecamethyl-3,7,10-triselenaoctasila[3.3.3]propellane,
Si2(Si-
Me2)6Se3 (6b) and Dodecamethyl-3,7,10-tritelluraoctasila[3.3.3]pro-
pellane, Si2(SiMe2)6Te3 (6c): A solution of 5a (0.31 g, 0.50 mmol)
in 1 mL THF was slowly added to a suspension of Li2E (E ϭ Se,
Te) prepared from 1.5 mmol elemental E and 3 mL of a 1  solu-
tion of Li[BEt3H] in THF. In the case of the tellurium compound
the reaction was carried out at Ϫ30 °C to prevent SiϪSi bond
cleavage reactions. After stirring for 30 min the solvent was re-
moved in vacuo and replaced by 10 mL hexane. Filtration from
precipitated lithium salts and removal of the solvents yielded the
propellanes 6b and 6c as colorless crystalline residues in 62 and
25% yield, respectively.
[15]
[16]
[17]
[18]
Spagna, J. Appl. Cryst. 1999, 32, 115Ϫ119.
G. M. Sheldrick, SHELX97, Programs for Crystal Structure
Analysis (Release 97Ϫ2), University of Göttingen, Germany
1997.
Diamond 2.1: K. Brandenburg, Crystal Impact GbR, Bonn,
[19]
[20]
Germany, 1999.
H. Gilman, C. L. Smith, J. Am. Chem. Soc. 1964, 86, 1454.
Acknowledgments
The authors thank the Deutsche Forschungsgemeinschaft for fi-
nancial support. Special thanks are given to Prof. H. Lang, Chair
[21]
Received May 31, 2001
[I01199]
3112
Eur. J. Inorg. Chem. 2001, 3107Ϫ3112