Novel chalcogenides of silicon with bicyclo[2.2.2]octane skeletons, MeSi(SiMe2E)3MR (E = S, Se, Te; M = Si, Ge, Sn; R = Me, Ph)

Article abstract of DOI:10.1021/om0105573

The reactions of 1:1 mixtures of the isotetrasilane MeSi(SiMe₂Cl)₃ and organo group 14 trichlorides RMCl₃ (R = Me, Ph; M = Si, Ge, Sn) with Li₂E (E = S, Se, Te) in THF yielded the new bicyclo[2.2.2]octanes MeSi(

Full text of DOI:10.1021/om0105573

Organometallics 2001, 20, 5369-5374
5369
Novel Ch a lcogen id es of Silicon w ith Bicyclo[2.2.2]octa n e
Sk eleton s, MeSi(SiMe2E)3MR (E ) S, Se, Te; M ) Si, Ge,
Sn ; R ) Me, P h )
Uwe Herzog*,† and Gerd Rheinwald‡
Institut fu¨r Anorganische Chemie, TU Bergakademie Freiberg, Leipziger Strasse 29,
D-09596 Freiberg, Germany, and Institut fu¨r Chemie, Lehrstuhl Anorganische Chemie,
TU Chemnitz, Strasse der Nationen 62, D-09111 Chemnitz, Germany
Received J une 25, 2001
The reactions of 1:1 mixtures of the isotetrasilane MeSi(SiMe2Cl)3 and organo group 14
trichlorides RMCl3 (R ) Me, Ph; M ) Si, Ge, Sn) with Li2E (E ) S, Se, Te) in THF yielded
the new bicyclo[2.2.2]octanes MeSi(SiMe2E)3MR (2-4). The products were identified by
multinuclear NMR spectroscopy. Trends of the NMR data are discussed. The molecular struc-
tures of MeSi(SiMe2S)3GeMe (2c), MeSi(SiMe2Se)3SiMe (3a ), MeSi(SiMe2Se)3GeMe (3c), and
MeSi(SiMe2Se)3SnMe (3e) are reported.
In tr od u ction
resulted in heterobicyclo[2.2.2]octanes which are useful
starting materials for heterobimetallic compounds with
Bicyclo[2.2.2]octanes are an interesting class of ring
systems because of their high symmetry. Several groups
have already reported on bicyclo[2.2.2]octanes contain-
ing silicon and other heteroelements. Bicyclo[2.2.2]-
octanes containing a branched heptasilane unit and a
group 15 element have been described by Hassler et al.1
They were obtained by reaction of the corresponding
trichloroheptasilane and an alkaline metal phosphide
or arsenide:
unsupported M-M′ bonds:7,8
These results led us to investigate whether it would
be possible to build up related bicyclo[2.2.2]octanes with
chalcogen atoms in place of the NR or SiMe2 units. In
the course of our previous investigations on silicon
chalcogenides derived from oligosilanes, we have shown
that cyclic and polycyclic compounds containing five-
and six-membered rings are preferred. Usually no
acyclic products are formed when chlorine-substituted
9
oligosilanes are treated with either H2S/NEt3 or Li2E
Gade et al. have used the branched tetrasilane MeSi-
(SiMe2Cl)3 (1) to build up tripodal amino ligands for
group 4, 14, and 15 metals. With 1 as the starting
material, the reaction with a primary amine yielded the
triamines MeSi(SiMe2NHR)3. Subsquent lithiation2 and
reaction with halides of group 4,3 14,4,5 or 156 elements
(E ) S, Se, Te).10-12
(4) Hellmann, K. W.; Steinert, P.; Gade, L. H.; Inorg. Chem. 1994,
33, 3859.
(5) Hellmann, K. W.; Gade, L. H.; Gevert, O.; Steinert, P. Inorg.
Chem. 1995, 34, 4069.
(6) Gade, L. H.; Findeis, B.; Gevert, O.; Werner, H. Z. Anorg. Allg.
Chem. 2000, 626, 1030.
* To whom correspondence should be addressed. E-mail:
Uwe.Herzog@chemie.tu-freiberg.de. Fax: +49/3731-394058.
† TU Bergakademie Freiberg.
(7) Findeis, B.; Schubart, M.; Platzek, C.; Gade, L. H.; Scowen, I.;
McPartlin, M. Chem. Commun. 1996, 219.
(8) Schubart, M.; Mitchell, G.; Gade, L. H.; Kottke, T.; Scowen, I.
J .; McPartlin, M. Chem. Commun. 1999, 233.
(9) Herzog, U.; Bo¨hme, U.; Roewer, G.; Rheinwald, G.; Lang, H. J .
Organomet. Chem. 2000, 602, 193.
‡ TU Chemnitz.
(1) Hassler, K.; Kollegger, G. M.; Siegl, H.; Klintschar, G. J .
Organomet. Chem. 1997, 533, 51.
(2) Schubart, M.; Findeis, B.; Gade, L. H.; Li, W.-S.; McPartlin, M.
Chem. Ber. 1995, 128, 329.
(3) Findeis, B.; Schubart, M.; Gade, L. H.; Mo¨ller, F.; Scowen, I.;
McPartlin, M. J . Chem. Soc., Dalton Trans. 1996, 125.
(10) Herzog, U.; Rheinwald, G. J . Organomet. Chem. 2001, 627, 23.
(11) Herzog, U.; Bo¨hme, U.; Rheinwald, G. J . Organomet. Chem.
2001, 627, 144.
(12) Herzog, U.; Rheinwald, G. J . Organomet. Chem. 2001, 628, 133.
10.1021/om0105573 CCC: $20.00 © 2001 American Chemical Society
Publication on Web 11/13/2001

5370 Organometallics, Vol. 20, No. 25, 2001
Herzog and Rheinwald
Ta ble 1. 29Si, 119Sn , 77Se, a n d 125Te NMR Da ta (δ in p p m a n d J in Hz) of th e Bicyclo[2.2.2]octa n es
RM(ESiBMe2)3SiAMe (2-4)
3
1J ME
δSi
δSi
1J SiSi
1J Si
J MSi
A
B
A
BE
compd
E
M
R
δE
δM
2a
2b
2c
2d
2e
2f
3a
3b
3c
3d
3e
3f
S
S
S
S
S
S
Se
Se
Se
Se
Se
Se
Te
Te
Te
Te
Si
Si
Me
Ph
Me
Ph
Me
Ph
Me
Ph
Me
Ph
Me
Ph
Me
Ph
Ph
Ph
Si: 11.4
Si: 2.9
-89.6
-88.4
-92.8
-91.2
-86.8
-85.6
-94.4
-93.0
-98.5
-96.6
-91.4
-89.8
-108.0
-105.7
-111.3
-103.1
-0.8
-0.5
0.9
65.8
65.8
66.1
65.6
65.8
65.8
65.6
65.1
65.7
65.1
65.1
65.1
63.1
17.3
14.9
Ge
Ge
Sn
Sn
Si
1.1
Sn: 66.3
Sn: 3.4
Si: -20.0
Si: -24.8
3.3a
133.6
129.5
17.2
3.5b
Se: -101
Se: -107
Se: -29
Se: -41
Se: -188
Se: -198
Te: -287
Te: -305
Te: -119
Te: -501
155.0
157.3
-5.5
-5.3
-4.6
-4.6
-3.6c
-3.6d
-27.0e
-26.8
-27.4
-28.9f
99.5
99.7
Si
16.3
Ge
Ge
Sn
Sn
Si
Si
Ge
Sn
103.1
103.0
104.4
103.8
262.4
Sn: -150.9
Sn: -200.0
Si: -146.5
1362
1387
378.4
142.4
138.3
4a
4b
4d
4f
Sn: -725
62.4
267.8
132.2
a
b 2
c 2
d
2
e 2
f 2
2
2J SiSn ) 24.4 Hz.
J
) 23.7 Hz.
J
) 27.8 Hz. J SiSn: 27.1 Hz.
J
) 10.9 Hz.
J
) 26.2 Hz and J SiTe ) 13.0 Hz.
SiSn
SiSn
SiTe
SiSn
Sch em e 1
Only in the case of the tellurium compounds are the
yields rather low and large amounts (up to 50%) of
byproducts are observed by NMR spectroscopy. How-
ever, in these cases the formation of bicyclo[2.2.2]-
octanes at all is remarkable. These are the first organo
group 14 tellurides with an RM(Te)3 coordination. While
organotrichlorides of silicon, germanium, and tin form
sesquichalcogenides with adamantane structures (R4-
M4E6) on treatment with either M2S or M2Se, no related
sesquitellurides have been reported so far and also our
attempts to obtain organosilicon tellurides with RSi(Te)3
units failed.12 The only exception may be the telluro-
germanate (Et4N)4Ge4Te10 with the adamantane-like
anion Ge4Te104-, prepared by extraction of an alloy of
the composition K4Ge4Te10 with ethylenediamine and
addition of Et4NBr.14 However, this anion bears no
organic substituents and has been prepared under quite
different reaction conditions.
The NMR data of all prepared bicyclo[2.2.2]octanes
are summarized in Table 1. A comparison of the 29Si
NMR chemical shifts of the isotetrasilane units of the
bicyclo[2.2.2]octanes with the compounds MeSiA(SiBMe2-
SBu)3 (δA, -79.4 ppm; δB, 4.8 ppm)15 and MeSiA(SiB-
Me2SeBu)3 (δA, -77.3 ppm; δB, -1.1 ppm)16 is remark-
able, because there are the same substitution patterns
at the silicon atoms but in acyclic compounds. While the
29Si NMR chemical shifts of the SiMe2 are close to the
values found in the bicyclo[2.2.2]octanes 2a -f and 3a -
f, large differences occur for the central SiMe units.
Previous investigations have shown that the incorpora-
tion of the silicon atoms into a six-membered ring
results in a high-field shift of the 29Si NMR signals.10
Concerning the central SiMe units, these silicon atoms
can be regarded as being incorporated into three six-
membered rings, which results in the strong high-field
shift of these signals in all synthesized bicyclo[2.2.2]-
octanes. Unfortunately, no related acyclic telluro-
substituted isotetrasilanes are known. Our attempts to
react methylchlorooligosilanes such as 1 with BuTeLi
resulted in excessive Si-Si bond cleavage.17 Similar
observations can be made by comparing the 29Si NMR
Resu lts a n d Discu ssion
MeSi(SiMe2Cl)3 (1) is a frequently used methylchloro-
oligosilane which can be obtained easily in two steps
from Me3SiCl and MeSiCl3 and by subsequent chlorina-
13
tion of the formed isotetrasilane MeSi(SiMe3)3 (see
Scheme 1).
In contrast to the formation of the N-containing
bicyclo[2.2.2]octanes discussed above, it is not necessary
to build up the bicyclic skeleton step by step: i.e., first
introduction of the three amino groups and then lithia-
tion and subsequent closure of the ring system by
reaction with a metal halide. The direct reaction of 1:1
molar mixtures of 1 and a group 14 trichloride (RMCl3,
M ) Si, Ge, Sn) with 3 equiv of Li2E (E ) S, Se, Te)
prepared in situ from elemental E and 2 equiv of Li-
[BEt3H] in THF results in clean formation of the desired
bicyclo[2.2.2]octanes (Scheme 1).
(14) Dhingra, S. S.; Haushalter, R. C. Polyhedron 1994, 13, 2775.
(15) Herzog, U.; Roewer, G. Main Group Met.Chem. 1999, 22, 579.
(16) Herzog, U. J . Prakt. Chem. 2000, 342, 379.
(13) Hassler, K. Monatsh. Chem. 1986, 117, 613.
(17) Herzog, U. Main Group Met. Chem. 2001, 24, 31.

Novel Chalcogenides of Silicon
Organometallics, Vol. 20, No. 25, 2001 5371
F igu r e 1. Effect of ring systems on the 29Si NMR chemical
shift in MeSiE3 units for E ) S, Se, Te.
chemical shifts of the RSiE3 unit of 2a -4a and 2b-4b
with those of the related silanes MeSi(SBu)3 (29.5 ppm),
PhSi(SBu)3 (22.7 ppm),15 MeSi(SeBu)3 (13.5 ppm), PhSi-
(SeBu)3 (11.3 ppm),16 and MeSi(TeBu)3 (-70.0 ppm).17
Here again the incorporation of the RSi(E)3 unit into
the bicyclo[2.2.2] skeleton causes a strong high-field
shift for the same R and E (see also Figure 1). Addition-
ally the 29Si NMR chemical shifts of the related silses-
quichalcogenides with adamantane-like structures are
presented in Figure 1; data are taken from ref 12. A
similar conclusion can also be drawn for M ) Sn when
comparing the 119Sn chemical shifts of 2e and 3e with
those of MeSn(SMe)3 (167 ppm)18 and MeSn(SeMe)3 (15
ppm).19
F igu r e 2. Molecular structure of 2c.
1
1
1
1
1
While the J SiSi, J SiSe, J SiTe, J SnSe, and J SiC values
observed in the bicyclo[2.2.2]octanes are in the expected
range for those coupling constants, the 3J constants
between the bridgehead atoms are remarkably large.
3J SiSi coupling constants of 15-17 Hz are observed in
n
2a ,b and 3a ,b, which are much larger than J SiSi (n >
1) in open-chain20,21 or simple cyclic22-24 oligosilanes.
3J SnSi coupling constants observed in 2e,f and 4e,f
F igu r e 3. Molecular structure of 3a .
3
(M ) Sn) are by a factor of 8-9 larger than J SiSi in
related bicyclo[2.2.2]octanes with M ) Si. This is
The molecular structures of 2c and 3a ,c,e have been
determined by X-ray analyses, and Figures 2 and 3 show
the molecular structures of 2c and 3a , respectively (the
atom numbering of 3c,e is analogous to that of 2c). Bond
lengths and angles are summarized in Tables 2-5. All
four compounds crystallize in the same space group with
similar cell constants (see Table 6).
All bond lengths are in the expected range. The
already described tendency that Si-E bond lengths
decrease with the number of sulfur substituents at
silicon can be observed again in 3a . While within the
SiSe3 unit the Si(1)-Se bonds are on average 2.276 Å,
the Si-Se bonds toward the isotetrasilane unit are on
average 2.309 Å. The Ge-S as well as Sn-Se bond
lengths of 2c and 3e are close to the values found in
the corresponding adamantanes (MeGe)4S6 (average
Ge-S 2.218 Å26) and (MeSn)4Se6 (average Sn-Se 2.528
Å27). The angles at the chalcogen atoms are within
103.1-104.7° for E ) S (2c) and 100.6-103.3° (3a ),
99.8-102.9° (3c), and 98.2-102.6° (3e) for E ) Se; in
approximately the same ratio as between the observed
1
1J SiASe (3a ,b) and J SnSe (3e,f) coupling constants. It had
been stated previously that the incorporation of silicon
into strained polycyclic ring systems results in remark-
ably large nJ SiSi (n > 1) coupling constants.25 In the case
of the bicyclo[2.2.2]octanes only coupling constants
between the bridgehead positions seem to be affected,
which can be seen in the observation of 3J MSiA and even
2
a
4J SnC value in 2f and 3f while J SiSi values are not
2
observed, and the measured J SnSi values are much
smaller than J SnSi values of the same compounds.
3
(18) Kenndey, J . D.; McFarlane, W. J . Chem. Soc., Perkin Trans. 2
1974, 146.
(19) Kennedy, J . D.; McFarlane, W. J . Chem. Soc., Dalton Trans.
1973, 2134.
(20) Kollegger, G.; Hassler, K. J . Organomet. Chem. 1995, 485, 233.
(21) Uhlig, F.; Kayser, C.; Klassen, R.; Hermann, U.; Brecker, L.;
Schu¨rmann, M.; Englich, U.; Ruhlandt-Senge, K. Z. Naturforsch. 1999,
54b, 278.
(22) Stu¨ger, H.; Eibl, M.; Hengge, E. J . Organomet. Chem. 1992,
431, 1.
(23) Uhlig, F.; Stadelmann, B.; Zechmann, A.; Lassacher, P.; Stu¨ger,
H.; Hengge, E. Phosphorus, Sulfur Silicon 1994, 90, 29.
(24) Po¨schl, U.; Siegl, H.; Hassler, K. J . Organomet. Chem. 1996,
506, 93.
(26) Benno, R. H.; Fritchie, C. J . J . Chem. Soc., Dalton Trans. 1973,
543.
(25) Kuroda, M.; Kabe, Y.; Hashimoto, M.; Masamune, S. Angew.
Chem., Int. Ed. Engl. 1988, 27, 1727.
(27) Blecher, A.; Dra¨ger, M.; Mathiasch, B. Z. Naturforsch. 1981,
B36, 1361.

5372 Organometallics, Vol. 20, No. 25, 2001
Herzog and Rheinwald
Ta ble 2. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) of 2c
Ta ble 4. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) of 3c
Bond Distances
Bond Distances
Ge(1)-S(1)
Ge(1)-S(2)
Ge(1)-S(3)
Si(2)-S(1)
Si(3)-S(2)
Si(4)-S(3)
Si(1)-Si(2)
Si(1)-Si(3)
Si(1)-Si(4)
2.2277(6)
2.2288(6)
2.2285(6)
2.1685(7)
2.1751(7)
2.1690(7)
2.3284(7)
2.3311(7)
2.3395(7)
Ge(1)-C(1)
Si(1)-C(2)
Si(2)-C(3)
Si(2)-C(4)
Si(3)-C(5)
Si(3)-C(6)
Si(4)-C(7)
Si(4)-C(8)
1.930(2)
1.892(2)
1.878(2)
1.867(2)
1.874(2)
1.873(2)
1.876(2)
1.871(2)
Ge(1)-Se(1)
Ge(1)-Se(2)
Ge(1)-Se(3)
Si(2)-Se(1)
Si(3)-Se(2)
Si(4)-Se(3)
Si(1)-Si(2)
Si(1)-Si(3)
Si(1)-Si(4)
2.3546(5)
2.3540(5)
2.3524(5)
2.2991(8)
2.3021(8)
2.3052(8)
2.3398(9)
2.3268(10)
2.3310(9)
Ge(1)-C(1)
Si(1)-C(2)
Si(2)-C(3)
Si(2)-C(4)
Si(3)-C(5)
Si(3)-C(6)
Si(4)-C(7)
Si(4)-C(8)
1.935(3)
1.890(3)
1.878(3)
1.873(3)
1.870(3)
1.863(3)
1.868(2)
1.866(3)
Bond Angles
Bond Angles
S(1)-Ge(1)-S(2)
S(1)-Ge(1)-S(3)
S(2)-Ge(1)-S(3)
Ge(1)-S(1)-Si(2)
Ge(1)-S(2)-Si(3)
Ge(1)-S(3)-Si(4)
111.77(2)
112.46(2)
110.03(2)
103.11(2)
104.72(2)
103.14(3)
S(1)-Si(2)-Si(1)
S(2)-Si(3)-Si(1)
S(3)-Si(4)-Si(1)
Si(2)-Si(1)-Si(3)
Si(2)-Si(1)-Si(4)
Si(3)-Si(1)-Si(4)
108.36(3)
106.28(3)
107.21(3)
107.05(3)
104.99(2)
106.11(3)
Se(1)-Ge(1)-Se(2) 113.27(1) Se(1)-Si(2)-Si(1) 109.11(3)
Se(1)-Ge(1)-Se(3) 109.96(2) Se(2)-Si(3)-Si(1) 109.17(3)
Se(2)-Ge(1)-Se(3) 112.45(2) Se(3)-Si(4)-Si(1) 106.79(3)
Ge(1)-Se(1)-Si(2)
99.82(2) Si(2)-Si(1)-Si(3) 107.28(3)
Ge(1)-Se(2)-Si(3) 100.40(2) Si(2)-Si(1)-Si(4) 107.77(3)
Ge(1)-Se(3)-Si(4) 102.91(2) Si(3)-Si(1)-Si(4) 108.71(4)
Torsion Angles
Torsion Angles
Ge(1)-S(1)-Si(2)-Si(1)
Ge(1)-S(2)-Si(3)-Si(1)
Ge(1)-S(3)-Si(4)-Si(1)
31.43(3)
32.24(3)
34.16(3)
Ge(1)-Se(1)-Si(2)-Si(1)
Ge(1)-Se(2)-Si(3)-Si(1)
Ge(1)-Se(3)-Si(4)-Si(1)
32.58(3)
30.87(3)
29.89(3)
Ta ble 3. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) of 3a
Ta ble 5. Selected Bon d Dista n ces (Å) a n d An gles
(d eg) of 3e
Bond Distances
Bond Distances
Si(1)-Se(1)
Si(1)-Se(2)
Si(1)-Se(3)
Si(2)-Se(1)
Si(3)-Se(2)
Si(4)-Se(3)
Si(2)-Si(5)
Si(3)-Si(5)
Si(4)-Si(5)
2.2722(7)
2.2794(7)
2.2770(7)
2.3054(7)
2.3011(7)
2.2996(7)
2.3271(9)
2.3232(10)
2.3345(8)
Si(1)-C(1)
Si(2)-C(2)
Si(2)-C(3)
Si(3)-C(4)
Si(3)-C(5)
Si(4)-C(6)
Si(4)-C(7)
Si(5)-C(8)
1.852(3)
1.866(3)
1.875(3)
1.865(3)
1.871(3)
1.874(3)
1.873(3)
1.888(3)
Sn(1)-Se(1)
Sn(1)-Se(2)
Sn(1)-Se(3)
Si(2)-Se(1)
Si(3)-Se(2)
Si(4)-Se(3)
Si(1)-Si(2)
Si(1)-Si(3)
Si(1)-Si(4)
2.5269(6)
2.5296(5)
2.5230(5)
2.3055(11)
2.3055(12)
2.3041(12)
2.3386(15)
2.3403(14)
2.3429(17)
Sn(1)-C(1)
Si(1)-C(2)
Si(2)-C(3)
Si(2)-C(4)
Si(3)-C(5)
Si(3)-C(6)
Si(4)-C(7)
Si(4)-C(8)
2.128(4)
1.890(4)
1.863(5)
1.871(6)
1.864(5)
1.869(5)
1.873(5)
1.881(4)
Bond Angles
Bond Angles
Se(1)-Si(1)-Se(2) 112.89(3) Se(1)-Si(2)-Si(5) 106.23(3)
Se(1)-Si(1)-Se(3) 111.00(3) Se(2)-Si(3)-Si(5) 108.63(3)
Se(2)-Si(1)-Se(3) 113.46(3) Se(3)-Si(4)-Si(5) 108.22(3)
Se(1)-Sn(1)-Se(2) 111.63(2) Se(1)-Si(2)-Si(1) 108.27(5)
Se(1)-Sn(1)-Se(3) 107.14(2) Se(2)-Si(3)-Si(1) 110.60(5)
Se(2)-Sn(1)-Se(3) 112.40(2) Se(3)-Si(4)-Si(1) 111.61(5)
Sn(1)-Se(1)-Si(2) 102.63(3) Si(2)-Si(1)-Si(3) 110.00(5)
Si(1)-Se(1)-Si(2)
Si(1)-Se(2)-Si(3)
Si(1)-Se(3)-Si(4)
103.30(3) Si(2)-Si(5)-Si(3)
100.96(2) Si(2)-Si(5)-Si(4)
100.63(2) Si(3)-Si(5)-Si(4)
108.09(4)
107.28(3)
106.19(3)
Sn(1)-Se(2)-Si(3)
Sn(1)-Se(3)-Si(4)
99.40(3) Si(2)-Si(1)-Si(4) 108.62(6)
98.20(3) Si(3)-Si(1)-Si(4) 109.34(6)
Torsion Angles
Torsion Angles
Si(1)-Se(1)-Si(2)-Si(5)
Si(1)-Se(2)-Si(3)-Si(5)
Si(1)-Se(3)-Si(4)-Si(5)
30.71(3)
30.92(4)
32.86(4)
Sn(1)-Se(1)-Si(2)-Si(1)
Sn(1)-Se(2)-Si(3)-Si(1)
Sn(1)-Se(3)-Si(4)-Si(1)
27.21(6)
30.68(5)
31.77(5)
all cases these are smaller than the tetrahedral angle.
This is in agreement with molecular structures of other
cyclic and polycyclic group 14 chalcogenanes.9-11 It is
remarkable that in 2c and 3a ,c as well as 3e two of the
angles M-E-Si are very similar while the third one is
on average 3° larger. In all four compounds character-
ized by X-ray structure analyses the ME3 cap is twisted
on average by 20° with respect to the SiSi3 unit. This
results also in the observed dihedral angles M-E-Si-
Si of approximately 30°.
phenylmethylpolysiloxane, column temperature 80 °C (3 min),
20 K/min, flow He 0.5 mL/min). The molecule peaks as well
as all identified fragments showed the expected patterns due
to the content of elements with several isotopes, namely Ge,
Sn, and Se.
2. Cr ysta l Str u ctu r e An a lysis. X-ray structure analysis
measurements were performed on a Bruker SMART CCD area
detector at 173 K, using Mo KR radiation (λ ) 0.710 73 Å,
graphite monochromator). Crystal data of 2c and 3a ,c,e as well
as data collection and refinement details are given in Table 6.
The unit cells were determined with the program SMART.28
For data integration and refinement of the unit cells the
program SAINT28 was used. The space groups were deter-
mined using the program XPREP.28 All data were corrected
for absorption using SADABS.29 The structures were solved
using direct methods (SHELX-9730), refined using full-matrix
least-squares methods on F2 (SHELX-97), and drawn using
Exp er im en ta l Section
1. NMR a n d GC/MS Mea su r em en ts. All NMR spectra
were recorded on a Bruker DPX 400 in CDCl3 solution and
TMS as internal standard for 1H, 13C, and 29Si. To get a
sufficient signal-to-noise-ratio of 29Si NMR spectra for resolving
n
1J SiC, 1J SiSi, nJ SiSe, nJ SiSn, or J SiTe satellites, 29Si INEPT spectra
were also recorded. 77Se, 119Sn, and 125Te spectra were mea-
sured using an IGATED pulse program. External Me4Sn, Ph2-
Se2 (δSe 460 ppm), and Ph2Te2 (δTe 422 ppm) in CDCl3 were
used as standards for 119Sn, 77Se, and 125Te.
(28) Bruker AXS Inc., Madison, WI, 1998.
(29) Sheldrick, G. M. Sadabs V2.01, Program for Empirical Absorp-
tion Correction of Area Detector Data; University of Go¨ttingen,
Go¨ttingen, Germany, 2000.
(30) Sheldrick, G. M. Shelx97: Programs for Crystal Structure
Analysis (Release 97-2); University of Go¨ttingen, Go¨ttingen, Germany,
1997.
Mass spectra were measured on a Hewlett-Packard 5971
(ionization energy 70 eV, column 30 m × 0.25 mm × 0.25 µm,

Novel Chalcogenides of Silicon
Organometallics, Vol. 20, No. 25, 2001 5373
Ta ble 6. Cr ysta l Da ta of 2c a n d 3a ,c,e a s Well a s Da ta Collection a n d Refin em en t Deta ils
2c
3a
3c
3e
empirical formula
cryst shape
cryst color
C8H24GeS3Si4
plate
colorless
C8H24Se3Si5
block
colorless
C8H24GeSe3Si4
block
colorless
C8H24Se3Si4Sn
rod
colorless
cryst size
fw
0.70 × 0.50 × 0.12
0.60 × 0.42 × 0.35
0.60 × 0.50 × 0.40
0.80 × 0.30 × 0.20
401.43
497.590
542.11
588.20
cryst syst
monoclinic
P21/c
monoclinic
P21/c
monoclinic
P21/c
monoclinic
P21/c
space group
unit cell dimens
a (Å)
b (Å)
c (Å)
10.2181(15)
11.6391(18)
16.638(3)
93.396(3)
1975.3(5); 4
1.350
2.090
ω scans
none
0.7875/0.3224
15886
5666
4398
0.0298
10.2283(6)
11.6430(7)
16.8521(9)
93.386(2)
2003.4(13); 4
1.650
5.788
ω scans
empirical
0.2365/0.1288
8657
10.238(2)
11.668(2)
16.914(2)
93.775(3)
2016.1(6); 4
1.786
7.154
ω scans
empirical
0.1620/0.0993
16133
10.3290(14)
11.7081(16)
17.066(2)
95.253(2)
2055.2(5); 4
1.901
6.771
ω scans
empirical
0.3445/0.0743
8972
â (deg)
V (Å3); Z
calcd density (g/cm3)
linear abs coeff (mm-1
scan method
abs cor
)
max/min transmissn
no. of measd rflns
no. of indep rflns
no. of obsd rflns
R(int)
4530
3801
0.0201
5779
4516
0.0330
4446
3222
0.0319
θ range for collecn (deg)
2.00-30.82
-14 e h e 14
-14 e k e 16
-23 e l e 18
91.3
0.0274/0.0649
0.0435/0.0707
0.0338/0.3826
1.008
1.99-29.44
-11 e h e 13
-10 e k e 15
-22 e l e 12
81.6
0.0257/0.0638
0.0332/0.0661
0.0410/0
1.99-30.88
-13 e h e 12
-16 e k e 9
-23 e l e 23
90.9
0.0269/0.0577
0.0430/0.0620
0.0281 /0
1.027
1.98-29.41
-13 e h e 9
-10 e k e 15
-19 e l e 21
78.3
0.0296/0.0566
0.0536/0.0629
0.0277/0
index ranges
completeness to θmax (%)
final R1/wR2 a (I > 2σ(I))
final R1/wR2 a (all data)
weighting scheme factors (a/b)a
goodness of fit (S)b on F2
no. of used rflns/params
H locating and refining
max/min e density (e/Å3)
0.997
0.955
5666/153
geom/constr
0.577/-0.363
4530/235
difmap/refall
0.380/-0.542
5779/153
geom/constr
0.423/-0.794
4446/241
difmap/refall
0.512/-0.710
a
2
2
b
R1 ) ∑(||Fo| - |Fc||)/∑|Fo|, wR2 ) [∑(w(Fo - Fc2)2)/∑(wFo2)]1/2), w ) 1/[σ2(Fo2) + (aP)2 + bP], where P ) (Fo + 2Fc2)/3. S )
[∑w(Fo - Fc2)2]/(n - p)1/2, n ) used reflections, p ) used parameters.
2
DIAMOND.31 The ellipsoids of the non-hydrogen atoms are
at the 50% probability level.
2b: Anal. Calcd for C13H26S3Si5 (418.98): C, 37.27; H, 6.25.
Found: C, 37.54; H, 6.18.
2c: GC/MS (m/e, relative intensity) 402 (M+, 5), 387 (M -
Me, 20), 313 (Me7Si4S3, 10), 281 (Me7Si4S2, 45), 223 (Me5Si3S2,
13), 191 (Me5Si3S, 23), 163 (Me5Si2S, 11), 131 (Me5Si2, 30), 116
3. Sta r tin g Ma ter ia ls. S, Se, Te, 1 M Li[BEt3H] in THF
(Super Hydride), RSiCl3, RGeCl3, and RSnCl3 (R ) Me, Ph)
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 by applying standard Schlenk techniques. MeSi(Si-
ClMe2)3 was prepared as described previously.32
4. P r ep a r a tion of th e Bicyclo[2.2.2]octa n es MeSi(Si-
Me2S)3MR (2a -f: M ) Si, Ge, Sn ; R ) Me, P h ). In a typical
reaction 96 mg (3.0 mmol) of sulfur was dissolved in a mixture
of 6.0 mL of a 1 M solution of Li[BEt3H] and an additional 3
mL of THF to form a Li2S solution. A mixture of 0.33 g (1.0
mmol) of 1 and 1.0 mmol of the appropriate RMCl3 (M ) Si,
Ge, Sn; R ) Me, Ph) dissolved in 1 mL of THF was added
slowly to the stirred Li2S solution in THF at 0 °C. After the
mixture was stirred for 20 min, the solvent was replaced by
10 mL of hexane. The product was filtered from precipitated
lithium chloride, and the solvent was removed in vacuo,
yielding the bicyclo[2.2.2]octanes 2a -f as crystalline residues
in 50-70% yield, with the exception of 2a , which remained a
colorless oil. In the case of the preparation of 2b,d larger
amounts of byproducts were observed by NMR spectroscopy
in the crude products. For further purification the products
were recrystallized from hexane.
(Me4Si2, 14), 73 (Me3Si, 100); mp 182 °C. Anal. Calcd for C8H24
-
GeS3Si4 (401.43): C, 23.94; H, 6.03. Found: C, 23.82; H, 6.51.
2d : GC/MS (m/e, relative intensity) 464 (M+, 11), 449 (M -
Me, 1), 387 (M - Ph, 2), 329 (Me5Si3S3Ge, 9), 313 (Me7Si4S3,
15), 281 (Me7Si4S2, 15), 223 (Me5Si3S2, 41), 209 (22), 178 (Me3-
Si2Ph, 14), 163 (Me2Si2Ph, 32), 135 (Me2SiPh, 100), 73 (Me3-
Si, 78).
2e: GC/MS (m/e, relative intensity) 433 (M - Me, 24), 375
(Me5Si3S3Sn, 2), 343 (Me5Si3S2Sn, 10), 313 (Me7Si4S3, 18), 281
(Me7Si4S2, 11), 223 (Me5Si3S2, 4), 191 (Me5Si3S, 37), 163 (Me5-
Si2S, 6), 131 (Me5Si2, 29), 73 (Me3Si, 100). Anal. Calcd for
C8H24S3Si4Sn (447.53): C, 21.47; H, 5.41. Found: C, 21.10; H,
5.73.
2f: GC/MS (m/e, relative intensity) 510 (M+, 3), 495 (M -
Me, 0.5), 433 (M - Ph, 40), 375 (Me5Si3S3Sn, 35), 343 (Me5-
Si3S2Sn, 11), 313 (Me7Si4S3, 19), 281 (Me7Si4S2, 19), 223 (Me5-
Si3S2, 23), 191 (Me5Si3S, 44), 153 (22), 135 (Me2SiPh, 75), 131
(Me5Si2, 27), 73 (Me3Si, 100).
5. P r ep a r a tion of th e Bicyclo[2.2.2]octa n es MeSi(Si-
Me2Se)3MR (3a -f: M ) Si, Ge, Sn ; R ) Me, P h ). A 0.24 g
quantity (3.0 mmol) of selenium powder was added to a
mixture of 6.0 mL of a 1 M solution of Li[BEt3H] and 3 mL of
THF to form a white Li2Se suspension. As described above, a
mixture of 0.33 g (1.0 mmol) of 1 and 1.0 mmol of the
appropriate RMCl3 (M ) Si, Ge, Sn; R ) Me, Ph) dissolved in
1 mL of THF was added slowly to the stirred Li2Se suspension
at 0 °C. Workup as described in part 4 yielded the bicyclo-
[2.2.2]octanes 3a -f in 50-70% yield as crystalline residues
which could be recrystallized from hexane for further purifica-
2a : GC/MS (m/e, relative intensity) 356 (M+, 31), 341 (M -
Me, 20), 297 (Me5Si4S3CH2, 12), 283 (Me5Si4S3, 11), 251 (Me5-
Si4S2, 3), 223 (Me5Si3S2, 5), 191 (Me5Si3S, 14), 176 (Me4Si3S,
14), 131 (Me5Si2, 17), 116 (Me4Si2, 16), 73 (Me3Si, 100).
(31) Berndt, M.; Brandenburg, K.; Putz H. Diamond 2.1; Crystal
Impact GbR, www.crystalimpact.de, Bonn, Germany, 1999.
(32) Herzog, U.; Schulze, N.; Trommer, K.; Roewer, G. J . Organomet.
Chem. 1997, 547, 133.

5374 Organometallics, Vol. 20, No. 25, 2001
Herzog and Rheinwald
tion, but in most cases no byproducts could be identified by
NMR spectroscopy.
mixture of 6.0 mL of a 1 M solution of Li[BEt3H] and 3 mL of
THF. The reaction mixture turned dark purple and became
light red after 1 h, after all tellurium had been consumed. A
mixture of 0.33 g (1.0 mmol) of 1 and 1.0 mmol of the
appropriate RMCl3 (M ) Si, Ge, Sn; R ) Me, Ph) dissolved in
1 mL of THF was added slowly to the stirred Li2Te suspension
at -30 °C. Workup as described in part 4 yielded yellow oily
residues containing the desired bicyclo[2.2.2]octanes 4a ,b,d ,f,
in addition to further unidentified byproducts as determined
by NMR spectroscopy. Because of the high reactivity toward
moisture and oxygen and the low thermal stability of 4a -f,
no further purification was attempted. On contact with oxygen
4a -f decompose almost immediately with formation of a black
precipitate of elemental tellurium.
3a : GC/MS (m/e, relative intensity) 498 (M+ (Me8Si5-
78Se80Se2), 6), 483 (M - Me, 4), 439 (Me5Si478Se80Se2CH2, 2),
425 (Me5Si478Se80Se2, 1), 377 (Me7Si480Se2, 1), 347 (Me5Si480Se2,
3), 319 (Me5Si380Se2, 2), 239 (Me5Si380Se, 11), 224 (Me4Si380Se,
7), 195 (Me3Si280SeCH2, 4), 131 (Me5Si2, 19), 116 (Me4Si2, 14),
73 (Me3Si, 100); mp 202 °C. Anal. Calcd for C8H24Se3Si5
(497.59): C, 19.31; H, 4.86. Found: C, 18.95; H, 4.70.
3b: GC/MS (m/e, relative intensity) 560 (M+ (Me7Si578Se-
80Se2Ph), 18), 545 (M - Me, 4), 501 (Me4Si478Se80Se2CH2Ph,
2), 487 (Me4Si478Se80Se2Ph, 4), 423 (2), 365 (4), 319 (Me5Si3-
80Se2, 5), 301 (10), 286 (18), 257 (12), 224 (Me4Si380Se, 8), 193
(Me4Si2Ph, 15), 178 (Me3Si2Ph, 20), 135 (Me2SiPh, 100), 131
(Me4Si2, 14), 105 (SiPh, 12), 73 (Me3Si, 56).
3c: GC/MS (m/e, relative intensity) 544 (M+ (Me8Si478Se-
80Se274Ge), 2), 529 (M - Me, 6), 377 (Me7Si480Se2, 13), 319 (Me5-
Si380Se2, 3), 239 (Me5Si380Se, 17), 211 (Me5Si280Se, 5), 195
(Me3Si280SeCH2, 4), 131 (Me5Si2, 22), 116 (Me4Si2, 8), 73 (Me3-
Si, 100). Anal. Calcd for C8H24GeSe3Si4 (542.11): C, 17.72; H,
4.46. Found: C, 17.33; H, 4.45.
Ack n ow led gm en t. We thank the Deutsche Fors-
chungsgemeinschaft for financial support. Special thanks
are given to Prof. H. Lang, Chair of Inorganic Chemis-
try, TU Chemnitz, for access to the X-ray facility used
to determine the single-crystal structures.
3d : GC/MS (m/e, relative intensity) 606 (M+ (Me7PhSi478Se-
80Se274Ge), 5), 471 (Me5Si378Se80Se274Ge, 9), 467 (9), 377 (Me7-
Si480Se2, 8), 330 (11), 317 (17), 281 (Me7Si4C5H4, 12), 207
(Me4Si2C7H7, 35), 178 (Me3PhSi2, 14), 135 (Me2PhSi, 82), 73
(Me3Si, 100).
Su p p or tin g In for m a tion Ava ila ble: A table giving 1H
and 13C NMR data of 2-4, tables of X-ray crystal data for 2c
and 3a ,c,e, and figures showing trends of 29Si, 77Se ,and 125Te
NMR chemical shifts and NMR spectra of the tellurium
compounds 4a -f. This material is available free of charge via
the Internet at http://pubs.acs.org.
3e: decomposes at 160 °C (turns black).
6. P r ep a r a tion of th e Bicyclo[2.2.2]octa n es MeSi(Si-
Me2Te)3MR (4a -f: M ) Si, Ge, Sn ; R ) Me, P h ). A 0.38 g
quantity (3.0 mmol) of tellurium powder was added to a
OM0105573