New chalcogen derivatives of silicon possessing adamantane and noradamantane structures

Article abstract of DOI:10.1016/S0022-328X(01)00782-3

The reaction of Si₂Cl₄Me₂ (1) with Li₂Se in THF yields exclusively the noradamantane (MeSi)₄Se₅ (4). The sulfur analogue (MeSi)₄S₅ (3) could be obtained from 1, MeSiCl

Full text of DOI:10.1016/S0022-328X(01)00782-3

Journal of Organometallic Chemistry 628 (2001) 133–143
www.elsevier.nl/locate/jorganchem
New chalcogen derivatives of silicon possessing adamantane and
noradamantane structures
U. Herzog 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 der TU Chemnitz, Straße der Nationen 62, D-09111 Chemnitz, Germany
Received 8 September 2000; received in revised form 14 December 2000; accepted 18 December 2000
Abstract
The reaction of Si2Cl4Me2 (1) with Li2Se in THF yields exclusively the noradamantane (MeSi)4Se5 (4). The sulfur analogue
(MeSi)4S5 (3) could be obtained from 1, MeSiCl3, H2S and NEt3. Reactions of the disilylmethane CH2(SiMeCl2)2 (5c) with either
H2S/NEt3 or Li2E (E=Se, Te) produced the new adamantanes (MeSi)4(CH2)2E4 (E=S (6), Se (7) and Te (8)). Similar reactions
of mixtures of 1 and 5c resulted in the formation of the noradamantanes (MeSi)4(CH2)E4 (E=S (9), Se (10)). All compounds were
characterized by multinuclear NMR spectroscopy. The crystal structures of 3, 6, 7, 8·CDCl3 and 9 are reported. © 2001 Elsevier
Science B.V. All rights reserved.
Keywords: Silthianes; Sulfur; Selenium; Tellurium; Noradamantane
A variety of silsesquithianes and -selenanes [5–7] as
well as the related germanium [8–10] and tin [11–14]
1. Introduction
compounds have been prepared by different methods,
but in most cases reactions of RMX3 (M=Si, Ge, Sn;
X=Cl, Br) with H2E (E=S, Se) in the presence of a
While polyhedral oligosilsesquioxanes (POSS), which
have received much attention in recent years [1–4],
form cube-octameric R8Si8O12 (I) or even larger cages,
base such as NEt3 or pyridine were applied.
silsesquithianes (and -selenanes) usually adopt adaman-
Table 1 summarizes some characteristic bond lengths
tane like structures (II) due to the much smaller bond
and angles of this class of compounds. It can be seen,
angle SiSSi (Scheme 1).
that in all these molecules the angles at the chalcogen
atom are smaller than the ideal tetrahedral angle of
109.5° while the angles EME are slightly expanded. The
angles deviate more from the tetrahedral angle if R is
an electron withdrawing substituent like C6F5 or CF3.
In the cases of sterically demanding substituents R the
reactions with Li2S or Li2Se yielded double-decker like
structures [(RME)2E]2 (R=1,1,2-trimethylpropyl: M=
Si, Ge; E=S, Se [15]; R=tbutyl: M=Si, E=S [16];
R=CpFe(CO)2: M=Si, E=Se [17]. The sulfur com-
pounds tend to isomerize to the more stable adaman-
tane derivatives on heating to 200°C [15,16]. Ando et
al. attempted the synthesis of silicon and germanium
chalcogenanes possessing bisnoradamantane structures
Scheme 1. Structures of R8Si8O12 (I) and R4Si4S6 (II).
t
by reacting BuMCl2–MClt2Bu (M=Si, Ge) with Li2E
(E=S, Se). While the expected bisnoradamantane (III)
could be isolated for M=Ge and E=S, the reactions
for M=Si and E=S or Se resulted in cleavage of one
* Corresponding author. Tel.: +49-3731-394343; fax: +49-3731-
394058.
E-mail address: herzog@merkur.hrz.tu-freiberg.de (U. Herzog).
0022-328X/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0022-328X(01)00782-3

134
U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
Table 1
Important bond parameters of silsesquichalcogenides and related germanium and tin compounds (RM)4E6 possessing an adamantane structure
,
R
M
E
dME (A)
ÚEME (°)
ÚMEM (°)
Ref.
H
Si
Si
S
S
S
S
Se
S
S
2.133, 2.137
2.129
2.20-2.22
2.210
112.0, 113.0
111.8
110.8–112.5
113.8
102.2, 103.0
104.5
104.2–105.0
99.9
[6]
[5]
[8]
[10]
[10]
[11,12]
[13]
[14]
Me
Me
CF3
CF3
Me
C6F5
Me
Ge
Ge
Ge
Sn
Sn
Sn
2.344
114.8
97.3
2.38–2.40
2.38–2.41
2.51–2.54
109.6–113.1
110.0–114.8
110.1–115.2
105.4–106.1
102.7–104.3
102.1–103.7
Se
SiSi bond and formation of the noradamantanes (IV) in
low yields (20 and 14%) [18] (Scheme 2).
In contrast to these reactions with lithium chalco-
genides, the reaction of MeCl2Si–SiCl2Me (1) with H2S
and NEt3 yielded a cage compound 2 containing three
disilane units without cleavage of SiSi bonds [19]:
The analogous sulfur compound 3 could be prepared
by reacting a mixture of one and two equivalents of
MeSiCl3 with H2S and NEt3.
Fig. 1 shows the molecular structure of one of the
two crystallographically independent molecules of 3 in
the asymmetric unit, characteristic bond distances and
angles are given in Table 2.
DFT calculations have shown, that in this case the
observed tetracyclic cage compound is by 59 kJ mol−1
more stable than 1.5 molecules of the corresponding
bisnoradamantane [19].
2. Results and discussion
2.1. Noradamantanes (MeSi )4E5 (E=S, Se)
In contrast to the formation of a cage compound 2 in
the reaction of 1 with H2S and NEt3 the reaction of 1
with Li2Se (prepared from Se and Li[BEt3H]) yielded
exclusively the noradamantane 4.
Scheme 2. Structures of bis-noradamantanes (III) and noradaman-
tanes (IV).
As expected, two 77Se-NMR signals could be ob-
1
2
served in a 4:1 ratio. Furthermore the JSiSe and JSiSe
satellites at SiA and two different JSiSe satellites in a 1:2
1
ratio at SiB in the 29Si-NMR spectrum prove the assign-
ment as a noradamantane.
The reaction of 1 with Li2Te under the same condi-
tions yielded no isolable products.
Fig. 1. Molecular structure of one of the two independent molecules
of 3.

U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
135
Table 2
bulky substituents. The two five membered rings adopt
envelope conformations with angles between the two
planes of 59.4 and 59.5°. The bond angle Si(1)–S(3)–
Si(4), which is part of six-membered rings only is by
more than 10° larger than the other Si–S–Si angles
which are also incorporated in five-membered rings.
This difference has also been found in other polycyclic
silthianes [19].
,
Important bond lengths (A) and bond angles (°) of one of the two
independent molecules of 3
Bond lengths
S(1)–Si(1)
S(1)–Si(2)
S(2)–Si(1)
S(2)–Si(3)
S(3)–Si(1)
S(3)–Si(4)
S(4)–Si(3)
S(4)–Si(4)
2.1453(16)
2.1505(13)
2.1498(12)
2.1580(14)
2.1524(15)
2.1628(14)
2.1550(14)
2.1483(13)
S(5)–Si(4)
S(5)–Si(2)
Si(1)–C(1)
Si(2)–C(2)
Si(3)–C(3)
Si(4)–C(4)
Si(2)–Si(3)
2.1540(16)
2.1606(14)
1.855(4)
1.851(5)
1.857(4)
The sulfur atoms form a tetragonal pyramid with an
almost ideal square as base. The S–S distances in the
1.845(5)
2.3729(14)
,
sulfur square lie in the range of 3.49–3.54 A, which is
,
by 0.2 A less than twice the van der Waals radius of
Bond angles
Si(1)–S(1)–Si(2)
Si(1)–S(2)–Si(3)
Si(1)–S(3)–Si(4)
Si(4)–S(4)–Si(3)
Si(4)–S(5)–Si(2)
S(1)–Si(1)–S(2)
S(1)–Si(1)–S(3)
S(2)–Si(1)–S(3)
S(1)–Si(2)–S(5)
94.12(5)
94.41(5)
106.65(6)
94.74(5)
94.74(5)
108.75(6)
110.46(6)
112.01(6)
109.51(6)
S(1)–Si(2)–Si(3)
S(5)–Si(2)–Si(3)
S(4)–Si(3)–S(2)
S(4)–Si(3)–Si(2)
S(2)–Si(3)–Si(2)
S(4)–Si(4)–S(5)
S(4)–Si(4)–S(3)
S(5)–Si(4)–S(3)
105.88(6)
105.18(6)
110.15(6)
104.93(5)
104.21(5)
108.61(6)
110.53(6)
111.57(6)
,
sulfur (3.7 A). The S–S distances to the sulfur atom at
the top of the pyramid are in the range of 3.53–3.57 A.
The nonbonding silicon–silicon distances between sili-
con atoms of the disilane unit and one of the other two
,
,
Si atoms are between 3.14 and 3.17 A, and the distance
,
Si(1)–Si(4) is 3.461 A, while twice the van der Waals
,
radius of silicon would be 4 A.
The NMR data of 3 and 4 are summarized and
compared with those of the related adamantane com-
pounds (MeSi)4E6 in Table 3.
The silicon sulfur as well as the silicon carbon bond
lengths are in the usual range while the Si–Si bond is
slightly longer than in normal disilanes [20] bearing no
A
comparison of the 29Si-NMR shifts of the
silsesquichalcogenanes (MeSi)4E6 with the acyclic com-
pounds MeSi(SBu)3 (lSi: 29.5 ppm) [21] and Me-
Table 3
NMR data of the silsesquichalcogenides Me4Si4E6 and noradamantanes Me4Si4E5 (E=S, Se) (chemical shifts in ppm, coupling constants in Hz)

136
U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
Table 4
1H-, 13C- and 29Si-NMR data of disilylmethanes 5a–c, CliMe3−iSi–CH2–SiCljMe3−j (i, j=1, 2) (chemical shifts in ppm, coupling constants in Hz)
Compound
lSi
lC
lH
CH3
CH2
CH3
CH2
1
1
ClMe2Si–CH2–SiClMe2 (5a)
Cl2MeSiA–CH2–SiBClMe2 (5b)
Cl2MeSi–CH2–SiCl2Me (5c)
28.5
A: 27.0; B: 28.3
25.9
4.3; JSiC: 58.3
10.9; JSiC: 49.1
14.3
0.49
A: 0.87; B: 0.56
0.93
0.565
0.92
1.28
A: 7.85; B: 4.1
1
1
7.5; JSiC: 71.1
17.5; JSiC: 59.9
Si(SeBu)3 (lSi: 13.5 ppm) [22] having the same first
coordination sphere at silicon reveal high field shifts of
12.3 and 13.7 ppm, respectively, in accordance with the
fact that the silicon atoms in the adamantanes are part
of six-membered rings, and the formation of this ring
size is usually accompanied by a 29Si-NMR high field
shift [19,23]. In the noradamantanes 3 and 4 the disi-
lane units are part of five-membered rings, and as
expected, the 29Si-NMR shifts are shifted to lower field
in comparison with the acyclic disilanes 1,2-
Me2Si2(SBu)4 (lSi: 9.1 ppm) [21] and 1,2-Me2Si2(SeBu)4
(lSi: −1.1 ppm) [22] by 14.8 ppm in 3 and 30.0 ppm in
4. On the other hand the two monosilyl units in 3 and
4 are part of both, five- and six-membered rings, which
in its sum results in a high field shift of 1.8 ppm for the
sulfur compound 3 versus MeSi(SBu)3 and 10.0 ppm
for the selenium compound 4 versus MeSi(SeBu)3.
The analogous selenium and tellurium compounds 7
and 8 could be prepared by reaction of 5c with two
equivalents of Li2Se or Li2Te, respectively:
The crystal structures of all three products could be
determined. To our knowledge 8·CDCl3 is the first
siltellurane with an adamantane structure, and only a
small number of crystal structure analyses of com-
pounds containing a Si–Te bond are known, e.g.
C6H4(NR)2Si(Te)2Si(NR)2C6H4 [26], tBu2Si(Te)2SitBu2
[27], (Me3Si)2Te (no crystal structure analysis),
(Me3Si)3SiTeH [28] and some derivatives [29–32],
Ph3SiTeH [33], Mes4Si2Te [34] or (Cp2Si)2Te3 [35]. This
is likely because of the high reactivity of the Si–Te
bond. While crystalline silthianes like 6 can be handled
in air for some minutes without decomposition, the
silselenane 7 slowly turns red under formation of sele-
nium, and siltelluranes like 8 decompose in air immedi-
ately into black elemental tellurium and siloxanes.
Solutions of these compounds are even more sensitive
towards moisture and air.
2.2. Silchalcogenanes (MeSi )4(CH2)2E4 (6–8)
2.2.1. Preparation of Cl2MeSiCH2SiMeCl2 (5c)
Chlorosubstituted disilylmethanes are formed as mi-
nor by-products in the direct process, i.e. reaction of
silicon with methyl chloride, but can not be separated
from this product mixture. The reaction of
(Me3Si)2CH2 with acetyl chloride (AcCl) and alu-
minium chloride [24] gave, depending on the reaction
conditions, ClMe2SiCH2SiClMe2 (5a), Cl2MeSiCH2-
SiClMe2 (5b) or Cl2MeSiCH2SiMeCl2 (5c):
Figs. 2–4 illustrate the molecular structures of 6, 7
and 8 showing the adamantane cages which become
The 29Si-NMR data of all chlorosubstituted disilyl-
methanes CliMe3−iSi–CH2–SiCljMe3−j have been re-
ported in [25] but our own results differ slightly from
1
literature values. The observed H-, 13C- and 29Si-NMR
chemical shifts of disilylmethanes are summed up in
Table 4.
2.2.2. Formation of (MeSi )4(CH2)2E4 (E=S (6), Se
(7), Te (8))
In a clean reaction treatment of disilylmethane 5c
with H2S and NEt3 yielded adamantane 6 containing
two methylene units in the cage.
Fig. 2. ORTEP plot of the molecular structure of 6.

U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
137
Table 5
,
Important bond lengths (A) and bond angles (°) of 6
Bond lengths
S(1)–Si(1)
S(1)–Si(3)
S(2)–Si(1)
S(2)–Si(2)
S(3)–Si(2)
S(3)–Si(4)
S(4)–Si(3)
S(4)–Si(4)
2.1446(12)
2.1479(13)
2.1461(12)
2.1475(13)
2.1323(13)
2.1439(12)
2.1399(13)
2.1408(12)
Si(1)–C(2)
Si(1)–C(3)
Si(2)–C(1)
Si(2)–C(4)
Si(3)–C(1)
Si(3)–C(5)
Si(4)–C(2)
Si(4)–C(6)
1.866(3)
1.860(4)
1.845(4)
1.880(4)
1.850(4)
1.873(4)
1.856(3)
1.853(4)
Bond angles
Si(1)–S(1)–Si(3)
Si(1)–S(2)–Si(2)
Si(2)–S(3)–Si(4)
Si(3)–S(4)–Si(4)
S(1)–Si(1)–S(2)
101.11(5)
101.20(5)
101.62(6)
101.40(5)
109.78(5)
S(3)–Si(2)–S(2)
S(4)–Si(3)–S(1)
S(4)–Si(4)–S(3)
Si(2)–C(1)–Si(3)
Si(4)–C(2)–Si(1)
110.47(6)
110.75(5)
110.32(5)
118.4(2)
119.4(2)
Fig. 3. ORTEP plot of the molecular structure of 7.
Table 6
,
Important bond lengths (A) and bond angles (°) of 7
Bond lengths
Se(1)–Si(1)
Se(1)–Si(3)
Se(2)–Si(1)
Se(2)–Si(2)
Se(3)–Si(2)
Se(3)–Si(4)
Se(4)–Si(3)
Se(4)–Si(4)
2.278(2)
2.276(2)
2.277(2)
2.278(2)
2.283(2)
2.281(2)
2.285(2)
2.280(2)
Si(1)–C(2)
Si(1)–C(3)
Si(2)–C(1)
Si(2)–C(4)
Si(3)–C(1)
Si(3)–C(5)
Si(4)–C(2)
Si(4)–C(6)
1.870(5)
1.855(5)
1.866(6)
1.859(5)
1.869(6)
1.864(6)
1.863(5)
1.865(6)
Fig. 4. ORTEP plot of the molecular structure of 8·CDCl3.
Bond angles
Si(1)–Se(1)–Si(3)
Si(1)–Se(2)–Si(2)
Si(2)–Se(3)–Si(4)
Si(3)–Se(4)–Si(4)
Se(1)–Si(1)–Se(2)
98.41(6)
98.39(5)
98.08(6)
98.26(6)
111.71(7)
Se(3)–Si(2)–Se(2)
Se(4)–Si(3)–Se(1)
Se(4)–Si(4)–Se(3)
Si(2)–C(1)–Si(3)
Si(4)–C(2)–Si(1)
110.88(7)
109.64(7)
109.71(7)
122.4(3)
122.7(3)
more and more distorted going down the Group 16
elements (S, Se, Te). The characteristic bond parame-
ters of 6–8 are given in Tables 5–7.
The bond lengths Si–C and Si–E (E=S, Se, Te) are
all in the expected range. In all three structures the four
chalcogen atoms span an almost ideal square with edge
,
,
lengths of dSS: 3.51–3.53 A in 6, dSeSe: 3.73–3.77 A in 7
Table 7
,
and dTeTe: 4.07–4.11 A in 8·CDCl3. But due to the
,
Important bond lengths (A) and bond angles (°) of 8·CDCl3
increasing bond lengths Si–SBSi–SeBSi–Te and the
fact that the bond angles at E tend to decrease in the
series S–Se–Te the octahedron of the four E atoms and
the two methylene carbons (C1 and C2) becomes more
and more flattened which can be seen by the increasing
ratio d(E(1)–E(3))/d(C(1)–C(2)) and the decreasing
Si–E–Si and increasing Si–C–Si angles, Table 8. In an
ideal adamantane cage both ratios, d(E(1)–E(3))/
d(C(1)–C(2)) and Ú(SiCSi)/Ú(SiESi), should be equal
to unity.
Bond lengths
Te(1)–Si(1)
Te(1)–Si(3)
Te(2)–Si(1)
Te(2)–Si(2)
Te(3)–Si(2)
Te(3)–Si(4)
Te(4)–Si(3)
Te(4)–Si(4)
Si(1)–C(2)
Si(1)–C(3)
2.511(2)
2.507(2)
2.491(2)
2.496(2)
2.503(2)
2.501(2)
2.499(2)
2.497(2)
1.854(10)
1.863(8)
Si(2)–C(1)
Si(2)–C(4)
Si(3)–C(1)
Si(3)–C(5)
Si(4)–C(2)
Si(4)–C(6)
C(7)–Cl(1)
C(7)–Cl(2)
C(7)–Cl(3)
1.881(8)
1.825(16)
1.847(13)
1.863(7)
1.879(8)
1.861(12)
1.750(9)
1.735(12)
1.777(16)
The tendency of tellurium to form such small bond
angles(Si–Te–Si: 93.6–94.2° in 8·CDCl3) may be the
reason why no organosilsesquitelluranes have been re-
ported so far and also our own attempts to isolate such
a compound failed while the corresponding sulfur and
selenium compounds are well known.
Bond angles
Si(1)–Te(1)–Si(3)
Si(1)–Te(2)–Si(2)
Si(2)–Te(3)–Si(4)
Si(3)–Te(4)–Si(4)
Te(1)–Si(1)–Te(2) 109.77(10)
Te(3)–Si(2)–Te(2) 109.41(9)
Te(4)–Si(3)–Te(1) 110.60(11)
93.83(7)
94.20(9)
93.57(10)
93.86(8)
Te(4)–Si(4)–Te(3)
Si(2)–C(1)–Si(3)
Si(4)–C(2)–Si(1)
Cl(1)–C(7)–Cl(2)
Cl(1)–C(7)–Cl(3)
Cl(2)–C(7)–Cl(3)
108.86(9)
127.2(6)
128.0(5)
111.5(7)
109.3(9)
109.7(6)
1
In Table 9 the H-, 13C-, 29Si-, 77Se- and 125Te-NMR
data of 6–8 are summarized, as well as those of the

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U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
Table 8
[21], 18.1 ppm (E=Se) [22] and −24.6 ppm (E=Te)
[36] and the monocyclic six-membered ring compounds
(Me2SiE)3 of 21.1 ppm (E=S), 15.2 ppm (E=Se) and
−23.7 ppm (E=Te) [37] having the same first coordi-
nation sphere at silicon. It is obvious, that in compari-
son with the acyclic compounds the formation of a
six-membered ring (Me2SiE)3 is accompanied by a high
field shift of 3–4 ppm for E=S, Se but a small down
field shift of 0.9 ppm for E=Te, and in an adamantane
structure, where the silicon atom is incorporated into
three six-membered rings, a further high field shift of
1.4 ppm (E=S), 5.3 ppm (E=Se) and 16.1 ppm (E=
Te) occurs. Compared with the six-membered rings
(Me2SiE)3 the 77Se- and 125Te-NMR shifts increase
from lSe= −244 ppm in (Me2SiSe)3 by 46 ppm in 7
and from lTe= −618 ppm in (Me2SiTe)3 by 125 ppm
Comparison of some geometric parameters of the compounds
Me4Si4E4(CH2)2, E=S (6), Se (7), Te (8) with an adamantane
skeleton
Parameter
6 (E=S) 7 (E=Se)
8 (E=Te)
,
d(C(1)–C(2)) (A)
d(E(1)–E(3)) and
d(E(2)–E(4)) (A)
d(E(1)–E(3))/d(C(1)–C(2)) 1.15
Average 1.17
Ú(SiCSi)/Ú(SiESi)
4.31
4.97
4.35
5.30
4.43
5.77, 5.79
,
1.22
1.25
1.30
1.36
noradamantanes 9 and 10. In order to estimate the
effects of the adamantane cage on the 29Si-NMR shifts
one can compare the values of 6–8 with those of the
acyclic compounds Me2Si(EBu)2 of 24.8 ppm (E=S)
1
in 8 while the coupling constants JSiE decrease slightly
Table 9
NMR data of the tetrachalcogenaadamantanes Me4Si4(CH2)2E4 (E=S, Se, Te) and -noradamantanes Me4Si4(CH2)E4 (E=S, Se) (chemical shifts
in ppm, coupling constants in Hz)

U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
139
The carbon sesquichalcogenides (MeC)4E6 (E=S,
Se) were formed in a similar reaction of acetyl chloride:
Fig. 5. ORTEP plot of one of the two independent molecules in the
crystal structure of 9.
Table 10
,
Important bond lengths (A) and bond angles (°) of the two indepen-
dent molecules of 9 {S(5)–S(8) and Si(5)–Si(8) are equivalent to
S(1)–S(4) and Si(1)–Si(4), C(6)–C(10) to C(1)–C(5)}
A crystal structure analysis has been performed for
(MeC)4S6, showing angles at sulfur in the range of
102.7–103.5° [42], which is close to the SiSSi angles in
(MeSi)4S6 and 6.
Bond lengths
S(1)–Si(1)
S(1)–Si(2)
S(2)–Si(1)
S(2)–Si(3)
S(3)–Si(2)
S(3)–Si(4)
S(4)–Si(3)
S(4)–Si(4)
Si(2)–Si(3)
Si(1)–C(1)
Si(2)–C(2)
Si(3)–C(3)
Si(4)–C(4)
Si(1)–C(5)
Si(4)–C(5)
2.1533(7)
2.1364(7)
2.1463(7)
2.1387(7)
2.1452(7)
2.1531(8)
2.1493(8)
2.1542(8)
2.3769(8)
1.846(2)
1.859(2)
1.855(2)
1.853(2)
1.870(2)
1.864(2)
S(5)–Si(5)
S(5)–Si(6)
S(6)–Si(5)
S(6)–Si(7)
S(7)–Si(6)
S(7)–Si(8)
S(8)–Si(7)
S(8)–Si(8)
Si(6)–Si(7)
Si(5)–C(6)
Si(6)–C(7)
Si(7)–C(8)
Si(8)–C(9)
Si(5)–C(10)
Si(8)–C(10)
2.1506(7)
2.1446(7)
2.1533(8)
2.1490(7)
2.1449(7)
2.1538(7)
2.1465(7)
2.1468(8)
2.3726(8)
1.856(2)
1.856(2)
1.848(2)
1.849(2)
1.865(2)
1.869(2)
2.3. Silchalcogenanes (MeSi )4(CH2)E4 possessing
noradamantane structures
Reaction of a 1:1 mixture of 1 and 5c with H2S and
NEt3 in hexane solution produced after workup the
new noradamantane 9 besides small amounts of the
adamantane compound 6:
Bond angles
Si(1)–S(1)–Si(2)
Si(1)–S(2)–Si(3)
Si(2)–S(3)–Si(4)
Si(3)–S(4)–Si(4)
S(1)–Si(1)–S(2) 107.66(3)
S(1)–Si(2)–S(3) 109.89(3)
S(2)–Si(3)–S(4) 110.16(3)
S(3)–Si(4)–S(4) 107.03(3)
Si(1)–C(5)–Si(4) 121.71(11)
92.96(3)
93.17(3)
92.74(3)
92.71(3)
Si(5)–S(5)–Si(6)
Si(5)–S(6)–Si(7)
Si(6)–S(7)–Si(8)
Si(7)–S(8)–Si(8)
S(5)–Si(5)–S(6)
S(5)–Si(6)–S(7)
S(6)–Si(7)–S(8)
S(7)–Si(8)–S(8)
Si(5)–C(10)–Si(8)
93.06(3)
92.82(3)
92.64(3)
92.84(3)
107.78(3)
109.08(3)
110.03(3)
107.54(3)
121.62(11)
The molecular structure of 9 is shown in Fig. 5
revealing the noradamantane skeleton consisting of
four silicon, four sulfur and one carbon atom. Some
important bond parameters are summarized in Table
10. The very enlarged angles Si–C–Si at the methylene
carbon atoms C(5) and C(10) of almost 122° are re-
markable. The angles at the sulfur atoms are in the
expected range for five-membered rings. In general the
structure is very similar to that of 3. Again, the four
sulfur atoms form an almost ideal square with S–S
by 2.4 Hz (2%) in 7 and by 15 Hz (4%) in 8. In general
it can be stated that the 125Te-NMR parameters (l,
1JSiE) parallel the 77Se-NMR parameters with a factor
of 2.5–2.6 [37].
Finally it should be mentioned that similar carbon
based oxides, sulfides and selenides (MeC)4(CH2)2E4
(E=O, S, Se) have been reported by Almqvist and
Olsson [38–41]. The compounds were obtained by reac-
tion of acetyl acetone with H2E (E=O, S, Se) in glacial
acetic acid in the presence of zinc chloride:
,
distances of 3.46–3.52 A and S–S–S angles between
89.5 and 90.3°. As in the noradamantane 3 the Si–Si
bond is slightly longer than in other disilanes as a result
of strain in the noradamantane cage.
Besides the NMR data, given in Table 9, 9 could also
be identified by its mass spectrum.

140
U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
If one compares the 29Si-NMR shifts of 9 with those
3.2. Crystal structure analysis
of the acyclic compounds Me2Si2(SBu)4 and
Me2Si(SBu)2 [21] the values are shifted to lower field by
14.0 ppm for the disilane unit and by 3.8 ppm for the
two monosilane units. This is again in good agreement
with the noradamantane structure where the disilane
unit is part of five-membered rings which results always
in a low field shift of this size as has already been
discussed [19,23]. The monosilane units are part in
both, five and six membered rings, which in its sum
results in this case in a small low field shift.
X-ray structure analysis measurements were per-
formed on a Bruker Smart CCD. Crystal data of 3, 6,
7, 8·CDCl3 and 9 as well as data collection and refine-
ment details are given in Table 11.
The unit cells were determined with the program
SMART [43]. For data integration and refinement of the
unit cells the program SAINT [43] was used. The space
groups were determined using the program XPREP [43].
All data were corrected for absorption using SADABS
[44]. The structures were solved using direct methods
The analogous selenium compound 10 could be pro-
duced by reacting a 1:1 mixture of 1 and 5c with Li2Se
in THF whereas the reaction with Li2Te did not yield
any soluble products:
(SHELX-97 [45]), refined using least-squares methods
(SHELX-97) and drawn using ZORTEP [46]. The ellip-
soides at the nonhydrogen atoms are at the 50% proba-
bility level.
3.3. Starting materials
H2S (N25, Air Liquide), Se, Te, triethylamine, 1 M
Li[BEt3H] in THF (Super Hydride), and the used
silanes MeSiCl3, MeCl2Si–SiCl2Me and CH2(SiMe3)2
were commercially available. 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 applying standard
Schlenk techniques.
The assignment of the disilane unit of 10 in the
29Si-NMR spectrum is simplified by the occurence of
2
1JSiSe as well as JSiSe satellites besides the fact that the
1
signal of the monosilyl units show two different JSiC
3.4. Noradamantanes Me4Si4E5 (E=Se (3), S (4)) and
adamantanes Me4Si4E6
satellites for the CH3 and the CH2 carbon atoms.
Again, compared with the 29Si chemical shifts of the
acyclic compounds Me2Si(SeBu)2 and Me2Si2(SeBu)4
[22] the disilane unit in 10 shows a strong low field shift
of 24.1 ppm while the signal of the two monosilyl units
remains almost unchanged (high field shift of 0.3 ppm)
which is in accordance with the noradamantane
structure.
A suspension of 0.2 g (2.5 mmol) powdered selenium
in 5 ml THF was treated with 5 ml of a 1 M solution
of Li[BEt3H] in THF under stirring. The solution be-
came colorless and some white precititation of Li2Se
occurred. 0.285 g (1.25 mmol) 1 were added under
stirring at 0°C. The precipitation of Li2Se disappeared
and the solution became slightly yellow. After 20 min
the solvent was removed in vacuo and replaced by 5 ml
toluene. After stirring for 1 h the mixture was filtered
from LiCl residue and yielded, after removal of the
solvent, 0.18 g (50%) 4 as a white powder. Recrystal-
lization from toluene gave very thin needles unsuitable
for X-ray analysis. In air the crystals turn red (elemen-
tal selenium) within a short time.
3. Experimental
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 get a sufficient
signal/noise ratio of 29Si-NMR spectra for obtaining
The sulfur compound 3 was obtained by reacting a
solution of 0.228 g (1 mmol) 1 and 0.299 g (2 mmol)
MeSiCl3 in 30 ml toluene with 1.4 ml (10 mmol) NEt3
while H2S passed through the stirred solution for 30
min. A white precipitation of HNEt3Cl was formed, the
mixture was filtered, and the solvent removed in vacuo.
The resulting white crystals of 3 are well soluble in
toluene and CDCl3 but less in hexane. Single crystals
were obtained from hexane solution.
1
1,2
1
1JSiC, JSiSi
,
J
SiSe
or JSiTe satellites also 29Si INEPT
spectra were recorded. 77Se and 125Te spectra were
recorded using an IGATED pulse program.
Mass spectra were measured on a Hewlett Packard
5971 (ionization energy: 70 eV, column: 30 m×0.25
mm×0.25 mm, phenylmethylpolysiloxane, column tem-
perature: 80°C (3 min)/20 K min−1, flow: He 0.5 ml
min−1).
3 GC/MS: m/e (rel. int.): 332 [M+, 75], 317 (M–Me,
2), 257 (Me3Si3S4, 100), 227 (MeSi3S4, 3), 165

U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
141
(Me3Si2S2, 14), 135 (MeSi2S2, 9), 75 (MeSiS, 12), 73
3.5. Chlorosubstituted disilylmethanes
(Me3Si, 9).
The silsesquichalcogenides Me4Si4E6 (E=S, Se) were
prepared from MeSiCl3 applying the procedures de-
scribed above while the analogous reaction with Li2Te
(prepared in situ as described below) did not yield a
toluene soluble product. The NMR data of the pre-
pared silsesquichalcogenides were similar to reported
values [7].
CH2(SiMe3)2 (4 g, 25 mmol) were mixed with 16 g
(120 mmol) of anhydrous AlCl3 and 9.5 g (120 mmol)
acetyl chloride were slowly added under intensive stir-
ring at room temperature. The mixture was heated
under stirring for two hours (80–90°C) to give a homo-
geneous yellow oil. The product was extracted three
times with 15 ml hexane and the combined hexane
solutions were concentrated in vacuo to yield 4.3 g of a
liquid residue containing 50% MeSiCl2CH2SiClMe2 (5b)
besides 45% MeSiCl2CH2SiCl2Me (5c) and 5%
Me4Si4S6 GC/MS: 364 [M+, 100], 349 (M–Me, 27),
257 (Me3Si3S4, 68), 165 (Me3Si2S2, 11), 135 (MeSi2S2,
6), 73 (Me3Si, 6).
Table 11
Crystal data of 3, 6, 7, 8·CDCl3 and 9 as well as data collection and refinement details
3
6
7
8·CDCl3
9
Crystal system
Space group
Unit cell dimensions
Monoclinic
C2/c
Triclinic
Triclinic
Triclinic
Triclinic
(
(
(
(
P1
P1
P1
P1
,
a (A)
16.2544(3)
21.2202(1)
13.9934(3)
90
111.495(1)
90
9.5560(7)
9.9653(7)
10.2440(7)
101.578(2)
108.065(2)
114.490(1)
2
9.1902(6)
9.5191(6)
10.0359(7)
93.4390(10)
108.7810(10)
99.9240(10)
2
9.0707(13)
10.8376(16)
12.5677(17)
72.891(3)
73.074(3)
87.304(3)
2
9.4227(12)
10.2681(13)
15.2832(19)
90.048(3)
91.896(3)
100.346(2)
4
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
Z
12
3
,
V (A )
4490.93(13)
1.477
780.49(10)
1.399
812.48(9)
2.111
1128.6(3)
2.443
1453.8(3)
1.438
Dcalc (g cm−3
)
Linear absorption
1.056
0.883
9.295
5.671
0.945
coeff. (mm−1
Radiation
)
Mo–Ka
173(2)
ꢀ scans
Empirical
Mo–Ka
173(2)
ꢀ scans
Empirical
Mo–Ka
173(2)
ꢀ scans
Empirical
Mo–Ka
173(2)
ꢀ scans
Empirical
Mo–Ka
173(2)
ꢀ scans
Empirical
Temperature (K)
Scan method
Absorption
correction
Max./min.
0.9017/0.8165
0.8738/0.6952
0.9467/0.5623
0.8049/0.0927
0.9282/0.5186
transmission
Measured reflections 10948
6529
4259
6389
4324
2224
2224
11951
7956
Independent
5358
reflections
Observed reflections 3015
2840
2788
1768
5669
Rint
0.0659
0.0250
0.0325
0.0000
0.0220
q Range for
collection (°)
Completeness to
qmax (%)
1.65–30.82
2.43–30.77
2.16–30.58
2.35–30.86
1.33–30.80
75.8
87.2
86.4
31.3
87.2
Refinement method Full-matrix
least-squares on F2
R1: 0.0470
Full-matrix
Full-matrix
Full-matrix
Full-matrix
least-squares on F2
R1: 0.0497
least-squares on F2
R1: 0.0436
least-squares on F2
R1: 0.0320
least-squares on F2
R1: 0.0300
Final R (I\2|(I))
R (all data)
H-locating and
refining
R1: 0.1191
difmap/refall
R1: 0.0872
difmap/refall
R1: 0.0839
difmap/refall
R1: 0.0417
difmap/refall
R1: 0.0532
difmap/refall
Goodness-of-fit on
0.927
1.018
0.955
1.101
0.959
F2
Max./min. e density 0.394/−0.433
1.249/−0.781
0.982/−1.019
0.598/−0.721
0.372/−0.299
−3
,
(e A
)

142
U. Herzog, G. Rheinwald / Journal of Organometallic Chemistry 628 (2001) 133–143
Me2SiClCH2SiClMe2 (5a). To get pure 5c the product
was treated again with 2.7 g (20 mmol) AlCl3 and 1.6 g
(20 mmol) acetyl chloride for 4 h at 120°C. Work-up as
described above yielded 2.5 g (10 mmol, 40%) pure 5c,
b.p.: 180°C.
Pure 5a can be obtained if the molar ratio of
CH2(SiMe3)2: AlCl3: acetyl chloride is changed to 1:2:2
and the reaction is carried out at room temperature
(yield: 40%).
5a: GC/MS: 185 (M–Me, 100), 165 (M–Cl, 15), 149
(ClMeSi(CH2)2SiMe, 10), 93 (Me2SiCl, 18), 73 (Me3Si,
9), 72 (Me2SiCH2, 12), 63 (SiCl, 9)
5c: GC/MS: 227 (M–Me, 100), 205/207 (M–Cl, 9/9),
189/191 (Cl2Si(CH2)2SiCl, 10/10), 113 (MeSiCl2, 19), 92
(MeSiClCH2, 27), 63 (SiCl, 25).
mixture of 0.228 g (1 mmol) 1 and 0.242 g (1 mmol) 5c,
dissolved in 30 ml toluene, with H2S and 1.1 ml (8
mmol) NEt3. After filtration and evaporation of the
solvent a crystalline residue of 9 in mixture with some 6
was obtained. By fractional crystallization from hexane
most of the much less soluble by-product 6 can be
removed. The second fraction of crystals (0.15 g) con-
sisted of 85% 9 besides 15% 6, as determined by NMR.
9 GC/MS: 314 [M+, 93], 299 (M–Me, 12), 239
(Me3Si3(CH2)S3, 100), 147 (8), 131 (5), 75 (MeSiS, 7),
73 (Me3Si, 4).
In analogy to the preparation of 7 a mixture of 0.228
g (1 mmol) 1 and 0.242 g (1 mmol) 5c were added to 4
mmol freshly prepared Li2Se in THF and after work-up
as described for 4 a crystalline product mixture contain-
ing approximately 80% 10 besides 15% 7 and 5% 4 was
isolated.
(The isotopic patterns are in all cases in agreement
with the number of chlorine atoms of the fragments
resulting in almost identical intensities of M and M+2
peaks for three Cl atoms. In both mass spectra a
fragment with a disilacyclobutane structure can be
obtained).
The analogous reaction with Li2Te did not yield any
soluble products.
4. Supplementary material
3.6. Adamantanes Me4Si4(CH2)2E4 (E=S (6), Se (7)
and Te (8))
Crystallographic (excluding structure factors) data
for the structural analysis have been deposited with the
Cambridge Crystallographic Data Centre, CCDC nos.
154127–154131 for compounds 3, 6, 7, 8·CDCl3 and 9,
respectively. Copies of this information may be ob-
tained from The Director, CCDC, 12 Union Road,
Cambridge CB2 1EZ, UK (fax: +44-1233-336-033;
e-mail: deposit@ccdc.cam.ac.uk or www: http://
www.ccdc.cam.ac.uk).
5c (0.36 g, 1.5 mmol) were dissolved in 20 ml toluene
and 0.83 ml (6 mmol) NEt3 were slowly added while
H2S bubbled through the solution. After filtration from
precipitated HNEt3Cl and removal of the solvent crys-
tals of pure 6 were obtained which could be recrystal-
lized from hexane, m.p.: 267°C.
6 GC/MS: 328 [M+, 100], 313 (M–Me, 93), 295 (10),
239 (Me3Si3S3CH2, 16), 221 (Me3Si3S2(CH2)2, 19), 147
(6), 131 (Me5Si2, 7), 75 (MeSiS, 4), 73 (Me3Si, 5).
The selenium compound 7 was obtained by addition
of 0.30 g (1.25 mmol) 5c to a solution of 2.5 mmol
Li2Se in THF (freshly prepared from 0.2 g (2.5 mmol)
Se, 5 ml THF and 5 ml of a 1 M solution of LiBEt3H
in THF). After work-up as described for the synthesis
of 4 colorless needles of 7 were obtained, which could
be recrystallized from toluene.
The tellurium compound 8 was prepared by essen-
tially the same procedure as described for 7 but 0.32 g
(2.5 mmol) tellurium powder were reacted with 5 ml of
a 1 M solution of LiBEt3H and 5 ml THF. But in
contrast to Li2Se, the formation of Li2Te takes more
than 1 h. The mixture turns initially deep purple and
becomes light red finally. After addition of 5c the
solution turns yellow-brown. The colorless crystals of 8
are extremely sensitive towards moisture and air and
turn black under formation of elemental tellurium.
Acknowledgements
The authors wish to thank the ‘Deutsche
Forschungsgemeinschaft’ for financial support. Special
thanks are given to Professor H. Lang, Chair of Inor-
ganic Chemistry, TU Chemnitz for the access to the
X-ray facility used to determine the single crystal
structures.
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