Syntheses and reactivity of stannyloligosilanes. 2. Branched stannyloligosilanes

Article abstract of DOI:10.1021/om000024e

Branched tri(stannyl)tetrasilanes MeSi[SiMe₂SnR₂R′]₃ (2, R = R′ = Ph; 3, R = R′ = Me; 5, R = t-Bu, R′ = H) were synthesized by the reaction of alkali metal tri- or diorganostannides with methyltris(fluorodimethylsilyl)silane (1) or methyltris(chlorodimethylsilyl)silane (4) or by reacting triphenylchlorostannane with 1 in the presence of magnesium. Methyltris-[hydridodi-tert-butylstannyl)dimethylsilyl]silane (5) was halogenated at the tin atom by treatment with CHCl₃ or CHBr₃. Surprisingly, the reaction of 5 with 3 equiv of lithium diisopropylamide (LDA) resulted in the formation of the five-membered ring 10 (2-dimethylsilyl-1,1,2,3,3-pentamethyl-4,4,5,5-tetra-tert-butyl- 1,2,3-trisila-4,5-distannacyclopentane) with a bridging Sn-Sn unit. Reacting 5 with triethylamine or aminostannanes resulted in the formation of 2-dimethylsilyl-1,1,2,3,3-pentamethyl-4,4,5,6,6- penta-tert-butyl-1,2,3-trisila-4,5,6-tristannacyclohexane (14). The solid-state structures of 5 and 14b were determined by X-ray crystallography.

Full text of DOI:10.1021/om000024e

2546
Organometallics 2000, 19, 2546-2550
Syn th eses a n d Rea ctivity of Sta n n yloligosila n es. 2.†
Br a n ch ed Sta n n yloligosila n es
Burkhard Costisella,‡ Ulrich Englich,§ Ingo Prass,‡ Markus Schu¨rmann,‡
Karin Ruhlandt-Senge,§ and Frank Uhlig*,‡
Fachbereich Chemie der Universita¨t Dortmund, Anorganische Chemie II, Otto-Hahn-Strasse 6,
D-44221 Dortmund, Germany, and Department of Chemistry and the W.M. Keck Center for
Molecular Electronics, 1-014 Center for Science and Technology,
Syracuse University, New York 13244-4100
Received J anuary 7, 2000
Branched tri(stannyl)tetrasilanes MeSi[SiMe2SnR2R′]3 (2, R ) R′ ) Ph; 3, R ) R′ ) Me;
5, R ) t-Bu, R′ ) H) were synthesized by the reaction of alkali metal tri- or diorganostannides
with methyltris(fluorodimethylsilyl)silane (1) or methyltris(chlorodimethylsilyl)silane (4) or
by reacting triphenylchlorostannane with 1 in the presence of magnesium. Methyltris-
[(hydridodi-tert-butylstannyl)dimethylsilyl]silane (5) was halogenated at the tin atom by
treatment with CHCl3 or CHBr3. Surprisingly, the reaction of 5 with 3 equiv of lithium
diisopropylamide (LDA) resulted in the formation of the five-membered ring 10 (2-di-
methylsilyl-1,1,2,3,3-pentamethyl-4,4,5,5-tetra-tert-butyl-1,2,3-trisila-4,5-distannacyclopentane)
with a bridging Sn-Sn unit. Reacting 5 with triethylamine or aminostannanes resulted in
the formation of 2-dimethylsilyl-1,1,2,3,3-pentamethyl-4,4,5,6,6-penta-tert-butyl-1,2,3-trisila-
4,5,6-tristannacyclohexane (14). The solid-state structures of 5 and 14b were determined
by X-ray crystallography.
Sch em e 1
In tr od u ction
Branched heptameric silanes of type A (E ) SiMe2,2
NR,3 Z ) Cl,2 H3) are important building blocks for the
synthesis of tetrasila- or heptasilabicyclo[2.2.2]octane
derivatives of type B (Scheme 1). Hassler et al. reported
the synthesis of cage-like compounds with capping
pnicogen atoms (E ) SiMe2; E′ ) P, As);2 Gade et al.
described a methyltris(aminodimethylsilyl)silane with
group 4 metals in identical positions (E ) NR; E′ ) TiCl,
ZrCl, HfCl).3
As far as we are aware, no reports describe the
synthesis of type A compounds in which E is an
organostannyl group. Previous work in our group was
concerned with the exploration of synthetic routes,
structural features, and reactivity of linear stannyloli-
gosilanes (t-Bu2Sn(Z)(SiMe2)nSn(Z)-t-Bu2; Z ) H, Cl, Br;
n ) 1-6).1 As a continuation of this work, we are now
reporting on the synthesis, structure, and reactivity of
the first heptameric stannasilanes (type A), in which E
is a di- or triorganostannyl group (E ) t-Bu2Sn; R3Sn).
First attempts toward cage-like compounds of type B
are also discussed.
THF served well in the preparation of methyltris-
[(triphenylstannyl)dimethylsilyl]silane (2), producing
yields of 80-90% (path a, eq 1). The trimethylstannyl-
substituted derivative 3 was obtained in 20% yield4 by
the reaction of sodium or potassium trimethylstannide
with 1. Treatment of methyltris(chlorodimethylsilyl)-
silane (4) with 3 equiv of lithium di-tert-butylstannide
gave methyltris[(di-tert-butylhydridostannyl)dimethyl-
silyl]silane (5) in 90% yield (path b, eq 1).
Resu lts a n d Discu ssion
The reaction of methyltris(fluorodimethylsilyl)silane
(1) with triphenylchlorostannane and magnesium in
† Part 1, see ref 1.
‡ Fachbereich Chemie der Universita¨t Dortmund.
§ Syracuse University.
(1) Uhlig, F.; Kayser, C.; Klassen, R.; Hermann, U.; Brecker, L.;
Schu¨rmann, M.; Ruhlandt-Senge, K.; Englich, U. Z. Naturforsch. 1998,
54b, 278.
(2) Hassler, K.; Kollegger, G.; Siegl, H.; Klintschar, G. J . Organomet.
Chem. 1997, 533, 51.
Triorgano-substituted derivatives 2 and 3 cannot be
functionalized at the tin atoms without cleavage of the
(3) (a) Gade, L. H.; Schubart, M.; Findeis, B.; Li, W.-S.; McPartlin,
M. Chem. Ber. 1995, 128, 329. (b) Gade, L. H.; Schubart, M.; Findeis,
B.; Platzek, C.; Scowen, I.; McPartlin, M. J . Chem. Soc., Chem.
Commun. 1996, 219.
(4) After “Kugelrohr“ distillation. The crude product was investi-
gated by NMR spectroscopy (119Sn and 29Si NMR). Integration of the
signals of the 119Sn NMR spectra showed more than 85% of 3.
10.1021/om000024e CCC: $19.00 © 2000 American Chemical Society
Publication on Web 05/27/2000

Branched Stannyloligosilanes
Organometallics, Vol. 19, No. 13, 2000 2547
Sch em e 2. Un exp ected F or m a tion of th e
F ive-Mem ber ed Rin g 10
Sch em e 3. Am in e Ca ta lyzed F or m a tion of 14a ,b
1,2-dilithio-1,1,2,2-tetra-tert-butyldistannide (11), was
identified by 119Sn NMR spectroscopy.
Treatment of the product mixture containing 10 and
11 with HCl or H2O, necessary for the isolation of 10,
converted 11 to t-Bu2Sn(H)Sn(H)-t-Bu2 (12).6 Reacting
5 with 1 or 2 equiv of LDA resulted in a mixture of the
starting material 5 and products 10 and 11. Although
we have little experimental support to suggest a mech-
anism for the formation of 10, we suggest that the first
step is the lithiation of one of the tin atoms in the
starting material, followed by tin-silicon bond cleavage
and amine-catalyzed intramolecular tin-tin coupling.
Amine-catalyzed ring closure and rearrangement reac-
tions of the stannasilane 5 have been observed when
reacting 5 with triethylamine or phenyltris(diethylami-
no)stannane. However, heating a solution of 5 and
phenyltris(diethylamino)stannane in toluene at 80 °C
for 1 week did not yield the expected cage compound
13 (Scheme 3);7 rather, the six-membered ring 14 with
a Sn3 and a Si3 units was isolated. Similar results were
obtained using triethylamine instead of phenyltris-
(diethylamino)stannane.
silicon-tin bonds. For example, when 3 was treated
with HgCl2, a mixture of 4, elemental mercury, and
Me3SnCl was obtained. The reaction of 3 with SnCl4
resulted in a mixture of 4, MeSnCl3, Me2SnCl2, and
Me3SnCl. Halogen-functionalized stannylsilanes are
accessible by treatment of 5 with bromoform or chloro-
form (eq 2).
The reactions of the branched oligomeric stannylsi-
lanes 2, 3, and 5 are similar to those of linear stannyl-
oligosilanes described previously.1 However, if a linear
monohydrido-substituted compound containing
a
Si-Sn chain is treated with lithium diisopropylamide
(LDA), metalation of the tin atom, under formation of
substituted LiSn-t-Bu2SiMePh2 8, and diisopropylamine
(eq 3) is observed. Disilylstannane 9, bearing of two
different silyl groups, was obtained by reacting 8 with
dimethylphenylchlorosilane (eq 4).
The central tin atom of 14 carries a tert-butyl group
and a hydrido function as a result of a silicon-tin and,
more surprising, tin-carbon bond cleavage. In addition,
two tin-tin bonds have been formed. Compound 14
contains two ring atoms (Si2 and Sn2) with different
substitution pattern. Accordingly, two sets of NMR
signals were observed for the four resulting equatorial-
axial isomers in a molar ratio of 3:1 (14a :14b).
+ LDA
LiSn-t-Bu SiMePh
HSn-t-Bu2SiMePh2
8
2
2
- HN-i-Pr2
8
(3)
+ PhMe SiCI8
2
LiSn-t-Bu2SiMePh2
- LiCI
8
PhMe2Si-Sn-t-Bu2SiMePh2
(4)
9
In contrast, reaction of the branched derivative 5 with
3 equiv of LDA did not result in the expected compound
with three metalated terminal tin atoms. At tempera-
tures below -10 °C no reaction was observed, whereas
above -10 °C a five-membered ring with a bridging tin-
tin unit and one exocyclic dimethylsilyl group (10) was
obtained (Scheme 2). The structure of 10 was confirmed
by NMR and MS experiments. Coupling constants for
The assignment of NMR chemical shifts in the isomer
mixture of 14a and 14b was achieved by a series of
119Sn-1H, 1H-1H, and 13C-1H COSY NMR experi-
ments. Compound 14 was isolated as a colorless oil,
which crystallized as a mixture of 14a and 14b at 0 °C.
(5) Uhlig, F.; Hermann, U.; Schu¨rmann, M. J . Organomet. Chem.
1999, 585, 211.
1
1J (Si-H) at 172 Hz and J (119Sn-117Sn) at 54 Hz were
(6) 119Sn NMR data for 12: δ -83.7 (1J (119Sn-1H) ) 1285 Hz;
observed. The latter agrees well with 1J (119Sn-117Sn)
for a previously reported stannasilacyclopentane with-
out an exocyclic silyl group, synthesized in a stepwise
reaction pathway.5 Only one tin-containing byproduct,
3J (119Sn-117Sn) ) 168 Hz).
(7) For formation of Sn-Sn bonds from the reaction of Sn-H with
R2N-Sn see: (a) Neumann, W. P. The Organic Chemistry of Tin;
Wiley: London, 1970. (b) Mitchell, T. N.; El-Bahairy, M. J . Organomet.
Chem. 1977, 141, 43.

2548 Organometallics, Vol. 19, No. 13, 2000
Costisella et al.
F igu r e 3. View of a molecule of 14b showing 50%
probability displacement ellipsoids and the atom number-
ing. Hydrogen atoms bonded to carbon have been removed
for clarity. Only one of the two independent molecules is
shown.
F igu r e 1. View of a molecule of 5 showing 30% probability
displacement ellipsoids and the atom numbering. Hydrogen
atoms bonded to carbon have been removed for clarity.
Ta ble 1. Cr ysta l Da ta a n d Str u ctu r e Refin em en t
for 5 a n d 14b
5
14b
formula
fw, g/Mol
cryst syst
cryst size, mm
space group
a, Å
C
31H78Si4Sn3
C27H68Si4Sn3
860.40
monoclinic
919.36
hexagonal
0.30 × 0.30 × 0.30 0.34 × 0.10 × 0.06
P6(3)
P2(1)/ c
13.066(1)
13.066(1)
16.238(1)
9.1358(5)
18.879(1)
46.986(3)
93.669(1)
8087.2(8)
4
1.415
1.971
3488
b, Å
c, Å
F igu r e 2. View (SHELXTL-PLUS) of a molecule of 14b
showing 50% probability displacement ellipsoids and the
atom numbering. Substituents at Si1, Si3, Sn1, Sn3 and
hydrogen atoms bonded to carbon were omitted for clarity.
Only one of the two independent molecules is shown.
â, deg
V, Å3
2400.8(3)
2
1.272
1.664
940
Z
F
calcd, Mg/m3
µ, mm-1
F(000)
We were able to isolate one of these isomers by frac-
tional crystallization from n-hexane. The NMR spectra
of a solution of these crystals showed that isomer 14b
had been isolated. The molecular structures of 5 and
14b are presented in Figures 1-3. Unit cell data,
refinement details, and selected interatomic details are
summerized in Tables 1 and 2.
Molecu la r Str u ctu r e of 5. Compound 5 contains a
tetrahedrally coordinated central silicon atom (Si(1))
connected to three Si(Me)2Sn(H)(t-Bu)2 arms in addition
to a methyl group. The hydrogen atom at Sn was located
in a difference map and refined. Bond distances are
2.346(2) Å for Si-Si, 2.599(2) Å for Sn-Sn, and 1.65(7)
Å for Sn-H. Silicon and tin atoms in the appendages
are of almost tetrahedral geometry; slight deviations
may be rationalized by steric effects. Similar deviations
from ideal tetrahedral geometry have been observed for
t-Bu2Sn(H)SiMe2SiMe2Sn(H)-t-Bu2, the only other struc-
turally characterized hydridostannyloligosilane,1 or other
methyl- or phenyl-substituted stannyloligosilanes.5,8
θ range, deg
3.09 to 25.67
-15 e h e 15
-13 e k e 13
-19 e l e 19
29 104
1.16 to 25.00
-10 e h e 10
-22 e k e 22
-55 e l e 43
43 398
14219/0.0991
616
1.001
index ranges
no. of reflns collected
no. of indep reflns/Rint 3045/0.025
no. of refined params
129
GooF (F2)
0.981
0.0403
0.1015
R1a (F) (I > 2σ(I))
wR2b (F2) (all data)
0.0582
0.1305
0.906/-1.065
largest diff peak/hole, 1.534/-0.650
e/Å3
a
b
R1 ) ∑||Fo| - |Fc||/∑|Fo|. wR2 ) x∑w {(Fo)2 - (Fc)2}/
∑w{(Fo)2}2.
atoms. Figure 2 displays a detailed view of the ring
system, while Figure 3 shows the entire molecule (in
both figures only one of the two independent molecules
is shown). The ring conformation is that of a distorted
boat, resulting from the approximate tetrahedral ge-
ometry of the ring atoms. Slight distortions from ideal
geometry are due to the different steric demands of the
ligands. Sn-Sn distances range from 2.8122(8) to
2.8157(8) Å, Sn-Si distances from 2.570(6) to 2.633(5)
Å. Si-Si contacts are observed between 2.326(4) and
2.373(7) Å. The hydrogen atoms at Si and Sn were
located in the difference Fourier maps and included in
the refinement. Sn-H distances were found at 1.55(8)
and 1.78(7) Å. Si-H contacts were observed at 1.34(10)
Molecu la r Str u ctu r e of 14b. Compound 14b crys-
tallizes with two independent molecules in each asym-
metric unit. The compound displays a six-membered
ring comprised of three neighboring silicon and tin
(8) Uhlig, F.; Kayser, C.; Klassen, R., Schu¨rmann, M. J . Organomet.
Chem. 1998, 556, 165.

Branched Stannyloligosilanes
Organometallics, Vol. 19, No. 13, 2000 2549
(Si(CH3)2, 1J (29Si-119/117Sn) ) 500/479 Hz, 3J (29Si-119Sn) ) 23
Hz). 119Sn{1H} NMR (149.19 MHz, CDCl3): δ -160.9. Anal.
Calcd for C61H66Si4Sn3 (1267.64): C, 57.80; H, 5.24. Found:
C, 58.1; H, 5.4.
Ta ble 2. Selected Bon d Len gth s (Å) a n d An gles
(d eg) for 5 a n d 14ba
5
14b
Bond Lengths
Me t h ylt r is[(t r im e t h ylst a n n yl)d im e t h ylsilyl]sila n e ,
MeSi(SiMe2Sn Me3)3 (3). Starting materials: 60 mmol of
NaSnMe3 in 80 mL of THF, 5.5 g (20 mmol) of 1 in 30 mL of
THF. The crude product was distilled to give 2.9 g (20%) of 3
as a colorless liquid, bp 153 °C (0.001 mmHg). 29Si{1H} NMR
(79.49 MHz, C6D6): δ -68.7 (SiCH3, 2J (29Si-119/117Sn) ) 56/53
Sn(1)-Si(2)
Sn(1)-H(1)
Si(1)-Si(2)
2.599(2) Sn(1)-Si(3)
2.624(3)
2.604(3)
2.816(1)
2.814(1)
2.340(4)
2.326(4)
2.352(4)
1.78(7)
1.65(7)
Sn(3)-Si(1)
2.346(2) Sn(1)-Sn(2)
Sn(2)-Sn(3)
Si(1)-Si(2)
Si(2)-Si(3)
Hz), -33,56 (Si(CH3)2, 1J (29Si-119/117Sn)
) 511/488 Hz,
Si(2)-Si(4)
3J (29Si-119Sn) ) 19 Hz). 119Sn{1H} NMR (149.19 MHz, C6D6):
δ -102.7. Anal. Calcd for C16H48Si4Sn3 (709.02): C, 27.1; H,
6.80. Found: C, 28.0; H, 7.0.
Sn(2)-H(2)
Si(4)-H(4)
1.34(10)
Bond Angles
C(8)-Sn(1)-C(4)
C(8)-Sn(1)-Si(2)
C(4)-Sn(1)-Si(2)
C(8)-Sn(1)-H(1)
C(4)-Sn(1)-H(1)
Si(2)-Sn(1)-H(1)
C(1)-Si(1)-Si(2)
113.1(4) C(1)-Sn(1)-C(5)
114.6(3) C(1)-Sn(1)-Si(3)
110.3(3) C(1)-Sn(1)-Sn(2)
110.6(3)
110.1(3)
108.1(2)
108.3(3)
106.7(2)
114.0(2)
117.1(2)
106.73(6)
Meth yltr is[(h ydr idodi-ter t-bu tylstan n yl)dim eth ylsilyl]-
sila n e, MeSi(SiMe2Sn -t-Bu 2H)3 (5). Starting materials: 11
mmol of LiSn(H)-t-Bu2,8 1.2 g (3.7 mmol) of 4. Recrystallization
from hexane gave 3.1 g (91%) of 5 as a colorless solid, mp 128
°C. 29Si{1H} NMR (79.49 MHz, C6D6): δ -68.1 (SiCH3,
117(3)
89(3)
C(5)-Sn(1)-Si(3)
C(5)-Sn(1)-Sn(2)
C(9)-Sn(2)-Sn(3)
109(2)
1
2J (29Si-119Sn) ) 30 Hz), -27.4 (Si(CH3)2, J (29Si-119/117Sn) )
109.8(1) C(9)-Sn(2)-Sn(1)
3
349/334 Hz, J (29Si-119Sn) ) 16 Hz). 119Sn{1H} NMR (149.19
Si(2)-Si(1)-Si(2a) 109.1(1) Si(1)-Sn(3)-Sn(2)
MHz, C6D6): δ -126.5. IR (Nujol): ν(Sn-H) ) 1777 cm-1
.
C(3)-Si(2)-C(2)
C(3)-Si(2)-Si(1)
C(2)-Si(2)-Si(1)
C(3)-Si(2)-Sn(1)
C(2)-Si(2)-Sn(1)
Si(1)-Si(2)-Sn(1)
106.9(4) Sn(3)-Sn(2)-Sn(1) 115.04(3)
109.0(3) Si(3)-Sn(1)-Sn(2)
108.5(3) Si(2)-Si(1)-Sn(3)
106.6(2) Si(3)-Si(2)-Si(1)
108.7(3) Si(2)-Si(3)-Sn(1)
116.8(1) C(27)-Si(4)-C(26)
C(27)-Si(4)-Si(2)
113.01(6)
114.0(1)
112.9(1)
111.6(1)
110.0(5)
113.9(4)
111.1(4)
Anal. Calcd for C31H78Si4Sn3 (919.42): C, 40.49; H, 8.55.
Found: C, 40.2; H, 8.40.
Meth yltr is[(ch lor od i-ter t-bu tylsta n n yl)d im eth ylsilyl]-
sila n e, MeSi(SiMe2Sn -t-Bu 2Cl)3 (6). Starting materials: 2.0
g (2.2 mmol) of 5, 1 mL of CHCl3, 15 mL of n-hexane.
Recrystallization from CHCl3 gave 0.8 g (35%) of 6 as a
colorless solid, mp 129-130 °C. 29Si NMR {1H} NMR (79.49
MHz, CDCl3): δ -62.2 (SiCH3, 2J (29Si-119Sn) ) 25 Hz), -15.5
C(26)-Si(4)-Si(2)
a
a ) -y + 1, x - y, z; b ) -x + y +1, -x +1, z.
1
3
(Si(CH3)2, J (29Si-119/117Sn) ) 247/236 Hz, J (29Si-119Sn) ) 18
Hz). 119Sn{1H} NMR (111.91 MHz, D2O-capillary/hexane): δ
70.0. Anal. Calcd for C31H75Cl3Si4Sn3 (1022.75): C, 36.40; H,
7.39. Found: C, 35.9; H, 7.2.
and 1.48(9) Å. These distances are in ranges observed
previously in related compounds.
Meth yltr is[(br om od i-ter t-bu tylsta n n yl)d im eth ylsilyl]-
sila n e, MeSi(SiMe2Sn -t-Bu 2Br )3 (7). Starting materials: 2.0
g (2.2 mmol) of 5, 0.1 mL of CHBr3, 15 mL of n-hexane.
Recrystallization from CH2Cl2 gave 1.0 g (86%) of 7 as a
colorless solid, mp 149-150 °C. 29Si NMR {1H} NMR (79.49
MHz, CDCl3): δ -61.6 (SiCH3, 2J (29Si-119Sn) ) 26 Hz), -15.7
(Si(CH3)2, 1J (29Si-119/117Sn) ) 234/223 Hz, 3J (29Si-119Sn) ) 18
Hz). 119Sn NMR {1H} NMR (149.19 MHz, CDCl3) δ 79.9. Anal.
Exp er im en ta l Section
Gen er a l Meth od s. All reactions were carried out under an
atmosphere of inert gas (N2 or Ar) using Schlenk techniques.
All solvents were dried by standard methods and freshly
distilled prior to use. Di-tert-butylstannane was prepared by
reduction of the corresponding dichloride with lithium alumi-
num hydride. The alkali metal stannides9,10 and the isotet-
rasilanes 1 and 411,12 were prepared according to published
procedures. All other chemicals used as starting materials
were obtained commercially. 1H and 13C NMR spectra were
recorded using a Bruker DRX 400 spectrometer (solvents
CDCl3 or C6D6, internal reference Me4Si). 29Si and 119Sn NMR
spectra were recorded using a Bruker DRX 400 spectrometer
(solvents CDCl3 or C6D6, internal reference Me4Si or Me4Sn,
respectively) or a Bruker DPX 300 spectrometer (solvents
hexane or THF with D2O-capillary, internal reference Me4Si
or Me4Sn, respectively). Mass spectral analyses were recorded
using a MAT 8200. Elemental analyses were performed on a
LECO-CHNS-932 analyzer. IR spectra were recorded on a
Bruker IFS 28 spectrometer.
Gen er a l P r oced u r es for 2, 3, 5-7, a n d 9. The stannyl-
silanes 2, 3, 5-7, and 9 were prepared according to the
procedures described in ref 1.
Me t h ylt r is[(t r ip h e n ylst a n n yl)d im e t h ylsilyl]sila n e ,
MeSi(SiMe2Sn P h 3)3 (2). Starting materials: 1.1 g (4 mmol)
of 1, 4.6 g (12 mmol) of Ph3SnCl, 80 mL of THF, 0.9 g (37 mmol)
of Mg. Recrystallization from diethyl ether gave 4.9 g (97%)
of 2 as a colorless solid, mp 127 °C. 29Si{1H} NMR (79.49 MHz,
CDCl3): δ -64.4 (SiCH3, 2J (29Si-119Sn) ) 56 Hz), -26.9
Calcd for
C31H75Br3Si4Sn3 (1156.11): C, 32.21; H, 6.54.
Found: C, 31.7; H, 6.6.
Lith iu m Meth yld ip h en ylsilyld i-ter t-bu tylsta n n a n e, Li
Sn -t-Bu 2-SiP h 2Me (8). A solution of LDA (5.4 mmol in 15 mL
of hexane and 15 mL of THF) was added dropwise to a cooled
(0 °C) solution of MePh2SiSn(H)-tert-Bu2 (1.25 g, 1.8 mmol) in
50 mL of hexane and 50 mL of THF. The reaction mixture
was stirred at 0 °C for 1 h. The reaction mixture was examined
by 29Si and 119Sn NMR spectroscopy. 29Si{1H} NMR (79.49
MHz, C6D6): δ -12.0 (1J (29Si-119/117Sn) ) not detected).
119Sn{1H} NMR (149.19 MHz, C6D6): δ -193.0. Dim eth yl-
p h en ylsilyl(d ip h en ylm eth ylsilyl)d i-ter t-bu tylsta n n a n e,
Me2P h SiSn -t-Bu 2SiP h 2Me (9). An LDA solution (2.9 mmol)
was added dropwise to a cooled solution (-30 °C) of 8 (1.25 g,
2.9 mmol) in 50 mL of hexane and 50 mL of THF. The reaction
mixture was stirred for 1 h, and dimethylphenylchlorosilane
(0.49 g, 2.9 mmol) was added. The solution was slowly warmed
to room temperature, 20 mL of petrolether (30-60) was added,
and the reaction mixture was hydrolyzed by addition of 10 mL
of water. The organic layer was separated and dried over
calcium chloride. After filtration (G3) and evaporation of the
solvents the resulting crude product was purified by column
chromatography (silica gel 60, hexane) to give 0.6 g (37%)
of 2 as a colorless solid, mp 66-68 °C. 29Si{1H} NMR (59.63
MHz, D2O/hexane): δ -11.4 (SiPhMe2, 1J (29Si-119/117Sn) ) 388/
371 Hz), -10.0 (SiPh2Me, 1J (29Si-119/117Sn) ) 379/362 Hz).
119Sn{1H} NMR (111.92 MHz, D2O/n-hexane): δ -185.1. Anal.
Calcd for C29H42Si2Sn (565.52): C, 61.59; H, 7.43. Found: C,
61.7; H, 7.7.
(9) Quintard, J .-P.; Pere`yre, M. Rev. Silicon, Germanium, Tin Lead
Compd. 1980, 4, 151.
(10) J ousseaume, B.; Connil, M.-F.; Pereyre, M. Organometallics
1996, 15, 4469.
(11) Suzuki, H.; Kimata, Y.; Satoh, S.; Kuriyama, A. Chem. Lett.
1995, 293.
(12) Kolleger, G.; Hassler, K. J . Organomet. Chem. 1995, 485, 233.

2550 Organometallics, Vol. 19, No. 13, 2000
Costisella et al.
2-Dim eth ylsilyl-1,1,2,3,3-p en ta m eth yl-4,4,5,5-tetr a -ter t-
b u t yl-1,2,3-t r isila -4,5-d ist a n n a cyclop en t a n e, MeSi(Si-
Me2H)(SiMe2Sn -t-Bu 2)2 (10). A solution of LDA (5.4 mmol
in 15 mL of hexane and 15 mL of THF) was added dropwise
to a cooled (0 °C) solution of 5 (1.65 g, 1.8 mmol) in 50 mL of
hexane and 50 mL of THF. The reaction mixture was stirred
at 0 °C for 1 h. The reaction mixture was examined by 29Si
and 119Sn NMR spectroscopy. 29Si{1H} NMR (79.49 MHz,
C6D6): identical with data found for isolated 10. 119Sn{1H}
NMR (149.19 MHz, C6D6): δ -98.1 (10), -8.6 (11).6
capillary/hexane): δ -334.8 [d, Sn(H)C(CH3)3, 1J (119Sn-1H)
) 1025 Hz, 3J (119Sn-1H) ) 75 Hz]. 119Sn{1H} NMR (149.19
MHz, C6D6): δ -334.8 [Sn(H)C(CH3)3, 1J (119Sn-119/117Sn) )
289/276 Hz], -72.2 [Sn(C(CH3)3)2, 1J (119Sn-119/117Sn) ) 289/
1
2
276 Hz, J (119Sn-29Si) ) 236 Hz, J (119Sn-117Sn) ) 41 Hz].
Cr ysta llogr a p h y of 5. The crystals were mounted on the
diffractometer in a sealed Lindemann capillary. The data were
collected at room temperature to a maximum θ of 25.67° with
360 frames via ω-rotation (∆/ω ) 1°) twice at 10 s per frame
on
a Nonius Kappa CCD diffractometer using graphite-
Subsequently, the reaction mixture was warmed to room
temperature, and 0.5 mL of H2O or dilute HCl (excess) was
added. The solvents were evaporated, and the resulting residue
was extracted twice with 80 mL of a diethyl ether/n-hexane
mixture (80:20). The extracts were filtered (G3), and after
evaporation of the solvents the resulting crude product was
purified by chromatography on silica gel using hexane as
eluent to give 0.44 g (35%) of 10 as a colorless solid, mp 40-
42 °C. 29Si NMR (79.49 MHz, C6D6): δ -75.0 (SiCH3,
monochromated Mo KR radiation (λ ) 0.71073 Å). The
structure was solved by direct methods (SHELXS97),13 Missing
atoms, including the hydrogen atom bound to Sn(1), were
located in subsequent difference Fourier cycles and refined by
full-matrix least-squares of F2 (SHELXL97).14 All other hy-
drogen atoms were placed geometrically and refined using a
riding model with a common isotropic temperature factor
(C-Hprim. 0.96 Å, Uiso 0.147(10) Å2). All non-hydrogen atoms
were refined using anisotropic displacement parameters.
Cr ysta llogr a p h y of 14b. The crystals were mounted on
the diffractometer as described previously.15 Intensity data
were collected at -182 °C with graphite-monochromated Mo
KR radiation (λ ) 0.71073 Å), using a Siemens SMART system,
complete with a three-circle goniometer and CCD detector
operating at -54 °C. Details regarding instrumentation and
data treatment have been reported previously.16 An absorption
correction was applied utilizing the program SADABS.17 The
crystal structure was solved by direct methods, as included in
the SHELXTL-Plus program package.18 Missing atoms, in-
cluding the hydrogen atoms on Si and Sn, were located in
subsequent difference Fourier maps and included in the
refinement. Remaining hydrogen atoms were placed geo-
metrically and refined using a riding model with Uiso con-
strained at 1.2 for nonmethyl groups and 1.5 for methyl groups
times Ueq of the carrier C atom. The structure was refined by
full-matrix least-squares refinement on F2 (SHELXL-93).19
Scattering factors were those provided with the SHELXL
program system. All non-hydrogen atoms, with the exception
of some disordered or restrained positions, were refined
anisotropically. Disorder was handled by including split posi-
tions for the affected groups and included in the refinement
of the respective occupancies. A set of restraints was applied
to aid in modeling the disorder.
1
2J (29Si-119Sn) ) 52 Hz), -33.0 (Si(CH3)2H, J (29Si-1H) ) 172
Hz, 2J (29Si-119Sn)
)
21 Hz), -28.1 (Si(CH3)2, 1J (29Si-
119/117Sn) ) 208/200 Hz, 2J (29Si-119Sn) ) 76 Hz). 119Sn{1H}
NMR (149.19 MHz, C6D6): δ -98.1 (1J (119Sn-117Sn) ) 54 Hz).
Anal. Calcd for C23H58Si4Sn2 (684.46): C, 40.36; H, 8.54.
Found: C, 40.8; H, 8.6.
2-Dim eth ylsilyl-4,4,5,6,6-p en ta -ter t-bu tyl -1,1,2,3,3-p en -
ta m eth yl-1,2,3-tr isila -4,5,6-tr ista n n a cycloh exa n e, MeSi-
(SiMe2H)(SiMe2Sn tBu 2)2Sn tBu H (14). Meth od A: Rea c-
tion s of 5 w ith P h en yltr is(d ieth yla m in o)sta n n a n e. A
solution of 5 (6.34 g, 6.9 mmol) and phenyltris(diethylamino)-
stannane (2.84 g, 6.9 mmol) in 200 mL of toluene was heated
and stirred for 16 h at 75 °C. The reaction mixture was then
examined by 119Sn NMR spectroscopy. 119Sn{1H} NMR (111.92
MHz, D2O-capillary/hexane): δ -94.6 [PhSn(NEt2)3], -126.5
[5]. Subsequently, the reaction mixture was heated for a
further 24 h at 95-100 °C. The solvents were evaporated, and
the resulting residue was examined by 119Sn NMR spectros-
copy. 119Sn{1H} NMR (111.92 MHz, D2O-capillary/hexane): δ
-37.9, -72.1, -83.8, -120.1, -121.6, -131.9, -335.1, -335.6.
Meth od B: Rea ction of 5 w ith Tr ieth yla m in e. A solu-
tion of 5 (0.46 g, 0.5 mmol) and 1 mL of triethylamine in 3 mL
of toluene was heated and stirred for 16 h at 90 °C. The
reaction mixture was then examined by 119Sn and 29Si NMR
spectroscopy. 29Si{1H} NMR (59.62 MHz, D2O-capillary/
toluene): δ -74.3, -70.8, -33.5, -33.1, -28.9, -27.7. 119Sn
NMR (111.92 MHz, D2O-capillary/toluene): δ -335.5, -334.8,
-83.9, -72.2. The crude product was purified by column
chromatography on silica gel using n-hexane as eluent to give
2.16 g of a yellow oil. Storage of the yellow oil in a refrigerator
(0 °C) gave 2.02 g (75%) of 14 as a colorless solid, mp 185 °C
(decomp). IR (Nujol): ν(Sn-H) ) 1765 cm-1. Anal. Calcd for
Ack n ow led gm en t. The authors thank the Deutsche
Forschungsgemeinschaft (DFG) and the state Northrhine
Westfalia for financial support. We thank also the ASV-
innovative Chemie GmbH (Germany) and the Degussa-
Huels AG for gifts of silanes. F.U. is grateful to Prof.
Dr. K. J urkschat for support. K.R.S. is grateful for
support by Syracuse University, the National Science
Foundation (CHE-9702246, CHE-97-02246), and the W.
M. Keck Foundation.
C
27H68Si4Sn3 (860.40): C, 37.7; H, 7.90. Found: C, 37.7; H,
8.5. Molecular weight determination (osmometric in hexane,
60 °C): calcd 860.40 g/mol; found 863.5 g/mol.
Isom er 14a : 29Si NMR (59.62 MHz, D2O-capillary/hex-
1
ane): δ -33.5 [d, Si(CH3)2H, J (29Si-1H) ) 176 Hz]. 29Si{1H}
Su p p or tin g In for m a tion Ava ila ble: The 13C and 1H
NMR data of all compounds, tables of all coordinates, aniso-
tropic displacement parameters, and geometric data for com-
pounds 5 and 14b are available free of charge via the Internet
at http://pubs.acs.org.
NMR (79.49 MHz, C6D6): δ -74.3 [SiCH3, 2J (29Si-119Sn) )
39 Hz, 3J (29Si-119Sn) ) 11 Hz], -33.5 [Si(CH3)2H], -27.7
[Si(CH3)2, 1J (29Si-119/117Sn) ) 219/211 Hz, 2J (29Si-119Sn) ) 63
Hz, 3J (29Si-119Sn) ) 10 Hz]. 119Sn NMR (111.92 MHz, D2O-
capillary/hexane): δ -335.5 [d, Sn(H)C(CH3)3, 1J (119Sn-1H)
) 1026 Hz, 3J (119Sn-1H) ) 77 Hz]. 119Sn{1H} NMR (149.19
MHz, C6D6): δ -335.5 [Sn(H)C(CH3)3, 1J (119Sn-119/117Sn) )
254/242 Hz], -83.9 [Sn(C(CH3)3)2, 1J (119Sn-119/117Sn) ) 254/
OM000024E
(13) Sheldrick, G. M. Acta Crystallogr. 1990, A46, 467.
(14) Sheldrick, G. M. SHELXL-97; University of Go¨ttingen, 1997.
(15) Chadwick, S.; Englich, U.; Noll, B.; Ruhlandt-Senge, K. Inorg.
Chem. 1998, 37, 4718.
1
2
242 Hz, J (119Sn-29Si) ) 221 Hz, J (119Sn-117Sn) ) 37 Hz].
Isom er 14b: 29Si NMR (59.62 MHz, D2O-capillary/hex-
ane): δ -34.5 [d, Si(CH3)2H, J (29Si-1H) ) 177 Hz]. 29Si{1H}
(16) Hope, H. Progr. Inorg. Chem. 1994, 41, 1.
1
NMR (79.49 MHz, C6D6): δ -70.8 [SiCH3, 2J (29Si-119Sn) )
37 Hz, 3J (29Si-119Sn) ) 11 Hz], -34.5 [Si(CH3)2H], -28.9
[Si(CH3)2, 1J (29Si-119/117Sn) ) 229/219 Hz, 2J (29Si-119Sn) ) 62
Hz, 3J (29Si-119Sn) ) 10 Hz]. 119Sn NMR (111.92 MHz, D2O-
(17) Sheldrick, G. M. SADABS, Program for Absorption Correction
Using Area Detector Data; University of Go¨ttingen, Germany, 1996.
(18) Siemens SHELXTL-Plus; Siemens: Madison, WI, 1996.
(19) Sheldrick, G. M. SHELXL-93; University of Go¨ttingen, Ger-
many, 1993.