The first spacer-bridged tetraorganodistannoxanes with a mixed double ladder structure

Article abstract of DOI:10.1002/1099-0682(20011)2001:1<153::aid-ejic153>3.0.co;2-m

The reaction of Me₃SiCH₂Cl₂ Sn(CH₂)₃SnCl₂Ph (6) with (tBu₂SnO)₃ gave a statistical mixture of the corresponding tetraorganodistannoxanes whereas the reaction of the spacer-bridged ditin tetrachlorides RCl₂Sn(CH₂)₄SnCl₂R (3, R = Me₃CCH₂; 4, R = Me₂CHCH₂; 10, R = Me₃SiCH₂) with the polymeric spacer-bridged ditin oxides [R(O)Sn(CH₂)₄-Sn(O)R]_n (7, R = Me₂CHCH₂; 8, R = Me₃CCH₂; 11, R = Me₃SiCH₂) provided the mixed double ladder compounds {[R(Cl)Sn(CH₂)₄ Sn(Cl)R][R′(Cl)Sn(CH₂)₄Sn(Cl)R′] O₂}₂ (9, R = Me₃CCH₂, R′ = Me₂CHCH₂; 12, R = Me₃CCH₂, R′ = Me₃SiCH₂) in almost quantitative yield. In solution, 9 and 12 are in equilibrium with their corresponding dimers, as was evidenced by ¹¹⁹Sn NMR spectroscopy, molecular mass determination, and electrospray mass spectrometry. The molecular structures of 9 and 12 were established by single crystal X-ray diffraction.

Full text of DOI:10.1002/1099-0682(20011)2001:1<153::aid-ejic153>3.0.co;2-m

FULL PAPER
The First Spacer-Bridged Tetraorganodistannoxanes with a Mixed Double
Ladder Structure[‡]
Michael Mehring,[a] Ingo Paulus,[a] Bernhard Zobel,[a] Markus Schürmann,[a]
Klaus Jurkschat,*[a] Andrew Duthie,[b] and Dainis Dakternieks*[b]
Keywords: Tin / Distannoxanes / Oxo complexes / Electrospray mass spectrometry
The reaction of Me3SiCH2Cl2Sn(CH2)3SnCl2Ph (6) with
(tBu2SnO)3 gave a statistical mixture of the corresponding Me3CCH2, RЈ = Me2CHCH2; 12, R = Me3CCH2, RЈ =
tetraorganodistannoxanes whereas the reaction of the Me3SiCH2) in almost quantitative yield. In solution, 9 and 12
spacer-bridged ditin tetrachlorides RCl2Sn(CH2)4SnCl2R (3, are in equilibrium with their corresponding dimers, as was
{[R(Cl)Sn(CH2)4Sn(Cl)R][RЈ(Cl)Sn(CH2)4Sn(Cl)RЈ]O2}2 (9, R =
R = Me3CCH2; 4, R = Me2CHCH2; 10, R = Me3SiCH2) with
the polymeric spacer-bridged ditin oxides [R(O)Sn(CH2)4-
Sn(O)R]n (7, R = Me2CHCH2; 8, R = Me3CCH2; 11, R =
Me3SiCH2) provided the mixed double ladder compounds
evidenced by 119Sn NMR spectroscopy, molecular mass de-
termination, and electrospray mass spectrometry. The mo-
lecular structures of 9 and 12 were established by single crys-
tal X-ray diffraction.
Introduction
organodistannoxanes {[R(X)SnϪZϪSn(X)R]O}n [X ϭ Cl,
F, OH, OAc; R ϭ alkyl; Z ϭ (CH2)3, (CH2)4, CH2Si-
Currently, there is much interest in dimeric tetraorgano- Me2CH2, CH2SiMe2CCSiMe2CH2].[18Ϫ21] In the solid state,
distannoxanes [R2(X)SnOSn(X)R2]2 (X ϭ halogen, OH, these compounds exhibit either a dimeric (n ϭ 2) or a
RЈCO2, NCS; R, RЈ ϭ alkyl, aryl)[1Ϫ5] since these com- double ladder structure (n ϭ 4). Furthermore, the first
pounds are reported to be efficient homogeneous catalysts triple ladder {[R(Cl)Sn(CH2)3Sn(Cl)(CH2)3Sn(Cl)R]O1.5
}
4
in various organic reactions such as transesterification un- (R ϭ Me3SiCH2) was reported, in which three Sn4Cl4O2
der virtually neutral conditions,[6] highly selective acylation layers are connected through trimethylene bridges.[22] The
of alcohols,[7] urethane formation,[8] and alkyl carbonate most convenient synthetic methodologies for the prepara-
synthesis.[9] X-ray crystallography has illustrated the di- tion of compounds of the type {[R(Cl)SnϪZϪSn(Cl)R]O}n
meric nature of a large number of tetraorganodistannox- (n ϭ 2, 4) are (i) the reaction of a spacer-bridged ditin tetra-
anes and NMR spectroscopic studies show that this struc- chloride RCl2SnϪZϪSnCl2R with (tBu2SnO)3 as the oxy-
tural arrangement is retained in solution.[1Ϫ5] However, gen transfer reagent and (ii) the reaction of a spacer-
only a few examples of monomeric species for both solution bridged ditin tetrachloride with the corresponding spacer-
and in the solid state have been reported.[2,4,10Ϫ13]
bridged polymeric ditin oxide [R(O)SnϪZϪSn(O)R]n.
In contrast to the symmetrically substituted tetraor-
In solution, most of the spacer-bridged distannoxanes re-
ganodistannoxanes, unsymmetrically substituted ones, such tain their solid-state structure, but in the cases of Z ϭ
as [Bu2(X)SnOSn(Y)Bu2]2 (X ϭ O2CMe, Cl, OPh, OMe; (CH2)4 and X ϭ Cl, OAc, and Z ϭ (CH2)3 and X ϭ OAc,
Y ϭ Cl, OPh, OMe),[2,4] [tBu2(Cl)SnOSn(Cl)R2]2 (R ϭ Me, equilibria between dimers and tetramers have been ob-
Et, iPr, nBu),[14] [tBu2(OH)SnOSn(Cl)R2]2 (R ϭ nBu, cyclo- served. These kinetically labile species show higher catalytic
hexyl),[14,15] [Ph2(Cl)SnOSn(OH)Ph2]2·2(CH3)2CO[16] and activity in acylation reactions than the kinetically more in-
[17]
Et2BrSnOSnBrPr2 have attracted less attention and only ert double ladder compounds.[18]
four of these compounds have been characterized by X-
Here we report our attempts to prepare mixed tetraor-
ganodistannoxanes and present the X-ray single crystal
ray crystallography.[14Ϫ16]
For some time we have been interested in the synthesis, structure analyses of {[R(Cl)Sn(CH2)4Sn(Cl)R][RЈ(Cl)-
structure, and catalytic activity of the spacer-bridged tetra- Sn(CH2)4Sn(Cl)RЈ]O2}2 (9, Me3CCH2, RЈ
R
ϭ
ϭ
Me2CHCH2; 12, R ϭ Me3CCH2, RЈ ϭ Me3SiCH2), the
This work contains parts of the Diploma thesis of M. Mehring, first mixed double ladders containing two different organic
[‡]
Dortmund University, 1995, and of the planned Ph. D. thesis
groups R and RЈ.
of I. Paulus.
[a]
Lehrstuhl für Anorganische Chemie II der Universität
Dortmund,
44221 Dortmund, Germany,
Results and Discussion
Fax: (internat.) ϩ 49-(0)231/755-5048,
E-mail: kjur@platon.chemie.uni-dortmund.de
Centre for Chiral and Molecular Technologies,
[b]
The unsymmetrically substituted ditin precursor
Deakin University,
Geelong, Victoria 3217, Australia
Me3SiCH2Cl2Sn(CH2)3SnCl2Ph (6) was prepared by reac-
Eur. J. Inorg. Chem. 2001, 153Ϫ160
WILEY-VCH Verlag GmbH, 69451 Weinheim, 2001
1434Ϫ1948/01/0101Ϫ0153 $ 17.50ϩ.50/0
153

K. Jurkschat, D. Dakternieks et al.
FULL PAPER
[22]
tion of Ph3SnNa (1) with Cl(CH2)3SnPh2CH2SiMe3
(2) [R(O)Sn(CH2)4Sn(O)R]n (8,
R
R
R
ϭ
ϭ
Me3CCH2), and
Me3CCH2) with
ϭ Me3SiCH2), gave
to give Me3SiCH2Ph2Sn(CH2)3SnPh3 (5) which was con- RCl2Sn(CH2)4SnCl2R (3,
verted into its tetrachloro-substituted derivative 6 by reac- [R(O)Sn(CH2)4Sn(O)R]n (11,
tion with HgCl2 (Scheme 1).
{[R(Cl)Sn(CH2)4Sn(Cl)R][RЈ(Cl)Sn(CH2)4Sn(Cl)RЈ]O2}2
(12, R ϭ Me3CCH2, RЈ ϭ Me3SiCH2) in almost quan-
titative yield. The mixed double ladder compounds 9
and 12 were also formed by mixing equimolar amounts
of the symmetrically substituted double ladders
{[R(Cl)Sn(CH2)4Sn(Cl)R]O}4, 14 (R ϭ Me3CCH2) and 15
(R ϭ Me2CHCH2), and 13 (R ϭ Me3SiCH2) and 14 (R ϭ
Me3CCH2), respectively, as was shown by 119Sn NMR ex-
periments in CHCl3/CDCl3 (Scheme 3). After 2 h of heating
at reflux, a complex mixture of different double ladders was
observed, whereas after 3 d of heating at reflux, the conver-
sion of the starting double ladders into the mixed ones 9
and 12, was complete. In contrast to the tetramethylene-
bridged double ladders reported here the trimethylene-
bridged double ladders {[R(Cl)Sn(CH2)3Sn(Cl)R]O}4 are
kinetically inert and do not show the formation of mixed
double ladders.[23]
Scheme 1. Synthesis of the unsymmetrically substituted trimethy-
lene-bridged ditin compound 6
The reaction of compound 6 with one-third molar
equivalent (tBu2SnO)3 gave a complex reaction mixture.
The 119Sn NMR spectrum of this mixture displayed 23 sig-
nals in the range of δ ϭ Ϫ90 to Ϫ210, in addition to the
resonance at δ ϭ 55 (assigned to tBu2SnCl2). This is close
to the 24 signals expected for a statistical distribution of 5
possible isomers with
a double ladder arrangement
(Scheme 2). It is most likely that the missing signal is super-
imposed with one of the 23 signals. Attempts to isolate a
single isomer failed.
Scheme 3. Syntheses of the mixed tetramethylene-bridged tetraor-
ganodistannoxanes 9 and 12
Scheme 2. Reaction of compound 6 with (tBu2SnO)3 giving a stat-
istical mixture of double ladder isomers
The molecular structure of compounds 9 and 12 are
shown in Figure 1 and Figure 2, respectively. Crystallo-
However, the reaction of the spacer-bridged ditin tetra- graphic data are given in Table 3 and selected geometrical
chloride RCl2Sn(CH2)4SnCl2R (3, R ϭ Me3CCH2) with the parameters are listed in Table 1. The compounds 9 and 12
spacer-bridged ditin oxide [R(O)Sn(CH2)4Sn(O)R]n (7, R ϭ form centrosymmetric tetramers in which two Sn4Cl4O2 un-
Me2CHCH2), as well as the reaction of RCl2Sn- its are linked through four tetramethylene bridges giving a
(CH2)4SnCl2R (4,
R ϭ Me2CHCH2) with [R(O)Sn- double ladder arrangement. The Sn4Cl4O2 layer is almost
(CH2)4Sn(O)R]n (8, R ϭ Me3CCH2) in toluene resulted in planar with the greatest deviation from the plane for Cl(2)
˚
˚
the almost quantitative formation of the mixed double [0.232(2) A] in 9 and Cl(3) [0.360(2) A] in 12. Each tin atom
ladder compound {[R(Cl)Sn(CH2)4Sn(Cl)R][RЈ(Cl)- has a distorted trigonal-bipyramidal geometry. For the exo-
Sn(CH2)4Sn(Cl)RЈ]O2}2 (9, Me3CCH2, RЈ cyclic tin atoms, two carbon atoms and one oxygen atom
Me2CHCH2) (Scheme 3). Analogously, the reactions of occupy the equatorial positions and two chlorine atoms the
R
ϭ
ϭ
RCl2Sn(CH2)4SnCl2R (10,
R
ϭ
Me3SiCH2) with axial positions, while for the endocyclic tin atoms the equat-
154
Eur. J. Inorg. Chem. 2001, 153Ϫ160

Spacer-Bridged Tetraorganodistannoxanes
FULL PAPER
Figure 2. General view (SHELXTL-Plus) of 12 showing 30% prob-
ability displacement ellipsoids and the atom numbering scheme
(symmetry transformations used to generate equivalent atoms: a ϭ
Ϫx ϩ 1, Ϫy, Ϫz Ϫ 1)
Figure 1. General view (SHELXTL-Plus) of 9 showing 30% prob-
ability displacement ellipsoids and the atom numbering scheme
(symmetry transformations used to generate equivalent atoms: a ϭ
Ϫx ϩ 1, Ϫy, Ϫz Ϫ 1)
endocyclic ones. The bond lengths and bond angles
orial positions are occupied by two carbon atoms and one (Table 1) correspond to those of previously described lad-
oxygen atom and the axial positions by one oxygen atom der[14] and double ladder structures.[18,19] The SnϪO bond
and one chlorine atom. In both structures the neopentyl lengths for the exocyclic tin atoms, Sn(1)ϪO(1) and
˚
groups Me3CCH2 are attached to the exocyclic tin atoms, Sn(4)ϪO(2), are 2.021(5) and 2.017(5) A, respectively, for
˚
and the isobutyl groups Me2CHCH2 (in 9) and the trime- 9, and 2.017(3) and 2.009(3) A, respectively, for 12. In the
thylsilylmethyl groups Me3SiCH2 (in 12) are bound to the four-membered Sn2O2 ring the SnϪO bonds are somewhat
˚
Table 1. Selected bond lengths [A] and angles [°] for 9 and 12
9
12
9
12
Sn(1)ϪO(1)
Sn(1)ϪCl(1)
Sn(1)ϪCl(2)
Sn(2)ϪO(1)
Sn(2)ϪO(2)
Sn(2)ϪCl(2)
Sn(2)ϪCl(4)
2.021(5)
2.809(2)
2.434(2)
2.125(5)
2.051(5)
3.320(2)
2.760(2)
2.017(3)
2.751(2)
2.478(2)
2.127(3)
2.058(3)
3.248(2)
2.724(2)
Sn(3)ϪO(1)
Sn(3)ϪO(2)
Sn(3)ϪCl(1)
Sn(3)ϪCl(3)
Sn(4)ϪO(2)
Sn(4)ϪCl(3)
Sn(4)ϪCl(4)
2.065(5)
2.134(5)
2.686(2)
3.326(3)
2.017(5)
2.488(2)
2.733(2)
2.052(3)
2.140(3)
2.752(2)
3.272(2)
2.009(3)
2.474(2)
2.760(2)
O(1)ϪSn(1)ϪC(1)
O(1)ϪSn(1)ϪC(11)
C(1)ϪSn(1)ϪC(11)
O(1)ϪSn(1)ϪCl(2)
C(11)ϪSn(1)ϪCl(2)
C(1)ϪSn(1)ϪCl(2)
O(1)ϪSn(1)ϪCl(1)
C(11)ϪSn(1)ϪCl(1)
C(1)ϪSn(1)ϪCl(1)
Cl(2)ϪSn(1)ϪCl(1)
O(2)ϪSn(2)ϪC(5)
O(2)ϪSn(2)ϪC(21)
C(5)ϪSn(2)ϪC(21)
O(2)ϪSn(2)ϪO(1)
C(5)ϪSn(2)ϪO(1)
C(21)ϪSn(2)ϪO(1)
O(2)ϪSn(2)ϪCl(4)
C(5)ϪSn(2)ϪCl(4)
C(21)ϪSn(2)ϪCl(4)
O(1)ϪSn(2)ϪCl(4)
O(1)ϪSn(3)ϪC(31)
O(1)ϪSn(3)ϪO(2)
C(31)ϪSn(3)ϪO(2)
O(1)ϪSn(3)ϪC(8)
120.5(3)
109.6(3)
123.5(3)
86.3(2)
107.3(3)
100.6(2)
75.0(2)
85.4(2)
84.0(2)
160.3(1)
107.1(3)
109.6(3)
142.1(3)
74.6(2)
99.5(3)
98.8(3)
75.7(2)
89.5(2)
90.7(3)
150.3(1)
109.9(3)
74.1(2)
96.6(3)
105.4(3)
106.2(2)
114.8(2)
136.7(3)
85.5(1)
96.5(2)
99.9(3)
76.5(1)
90.9(2)
85.6(3)
162.0(1)
114.9(4)
109.1(2)
135.5(5)
74.6(1)
98.0(5)
99.6(2)
76.5(1)
95.2(4)
88.6(2)
151.1(1)
109.6(2)
74.5(1)
101.1(2)
104.9(3)
C(31)ϪSn(3)ϪC(8)
O(1)ϪSn(3)ϪCl(1)
C(31)ϪSn(3)ϪCl(1)
O(2)ϪSn(3)ϪCl(1)
C(8)ϪSn(3)ϪCl(1)
O(2)ϪSn(3)ϪC(8)
O(2)ϪSn(4)ϪC(41)
O(2)ϪSn(4)ϪC(4)
C(41)ϪSn(4)ϪC(4)
O(2)ϪSn(4)ϪCl(3)
C(41)ϪSn(4)ϪCl(3)
C(4)ϪSn(4)ϪCl(3)
O(2)ϪSn(4)ϪCl(4)
C(41)ϪSn(4)ϪCl(4)
C(4)ϪSn(4)ϪCl(4)
Cl(3)ϪSn(4)ϪCl(4)
Sn(1)ϪCl(1)ϪSn(3)
Sn(2)ϪCl(4)ϪSn(4)
Sn(1)ϪO(1)ϪSn(3)
Sn(1)ϪO(1)ϪSn(2)
Sn(3)ϪO(1)ϪSn(2)
Sn(4)ϪO(2)ϪSn(2)
Sn(4)ϪO(2)ϪSn(3)
Sn(2)ϪO(2)ϪSn(3)
144.4(3)
77.3(1)
89.5(3)
151.1(1)
93.7(2)
97.4(3)
104.3(3)
118.4(3)
136.3(4)
86.6(2)
95.7(3)
95.3(2)
76.9(2)
90.2(3)
91.1(2)
163.4(1)
82.5(1)
82.2(1)
125.0(2)
128.4(2)
105.5(2)
125.2(3)
129.0(3)
105.7(2)
144.5(3)
76.0(1)
88.1(2)
150.4(1)
92.2(2)
96.0(2)
110.3(2)
109.7(3)
137.9(3)
85.0(1)
96.4(2)
99.7(3)
76.4(1)
91.0(2)
85.9(3)
161.3(1)
82.0(1)
82.2(1)
125.0(1)
128.2(2)
105.6(2)
124.7(2)
129.8(2)
104.9(2)
Eur. J. Inorg. Chem. 2001, 153Ϫ160
155

K. Jurkschat, D. Dakternieks et al.
FULL PAPER
lengthened, with the longest bonds found for Sn(2)ϪO(1)
˚
˚
[2.125(5) A] and Sn(3)ϪO(2) [2.134(5) A] (9), and for
˚
˚
Sn(2)ϪO(1) [2.127(3) A] and Sn(3)ϪO(2) [2.140(3) A] (12).
Two of the chlorine atoms of each monolayer form
SnϪClϪSn bridges [Sn(1)ϪCl(1)ϪSn(3) 82.5(1)° (9),
82.0(1)° (12), Sn(2)ϪCl(4)ϪSn(4) 82.2(1)° (9), 82.2(1)°
(12)], with Sn(1)ϪCl(1), Sn(3)ϪCl(1), Sn(4)ϪCl(4) and
Sn(2)ϪCl(4) bond lengths of 2.809(2), 2.686(2), 2.733(2),
˚
Scheme 5. Dimer-tetramer equilibrium in solutions of 9 (R ϭ
Me3CCH2, RЈ ϭ Me2CHCH2) and 12 (R ϭ Me3CCH2, RЈ ϭ
Me3SiCH2)
and 2.760(2) A (9), respectively, and 2.751(2), 2.752(2),
2.760(2), and 2.724(2) A (12), respectively. The chlorine
˚
atoms Cl(2) and Cl(4) can be regarded as non-bridging, al-
˚
˚
though the Sn(2)ϪCl(2) [3.320(2) A (9), 3.248 (2) A (12)]
˚
˚
and Sn(3)ϪCl(3) [3.326(3) A (9), 3.272 (2) A (12)] distances
The 119Sn NMR spectroscopic data in CDCl3 of the
mixed double ladders 9 and 12, and of the related simple
double ladders 13؊15 are given in Table 2. A solution of
crystalline 9 in toluene shows two pairs of signals of equal
integral ratio at δ ϭ Ϫ85.2 (26%)/Ϫ148.5 (27%) and at δ ϭ
Ϫ86.4 (15%)/Ϫ147.9 (15%) which are assigned with caution
to 9a and 9b. The resonances at δ ϭ Ϫ78.7 (5%),Ϫ150.2
(5%), and Ϫ85.4 (4%),Ϫ152.7 (3%) are assigned with cau-
tion to one of the two possible isomers of the dimer 9d, but
we were not able to discriminate the cis and the trans iso-
mer. In principal, these signals could also be assigned to
the tetramer 9c (Scheme 4), for which four signals of equal
integral ratio are expected. However, the molecular mass
determination of a solution of 9 in CHCl3 is indicative of
an equilibrium between tetramers and dimers, and thus we
assign the four signals to the dimer 9d rather than to the
tetramer 9c. In CDCl3 solution, 9 displays two signals of
equal integral ratio at δ ϭ Ϫ83.0 (36%) and δ ϭ Ϫ145.2
(35%) which are assigned to 9a and/or 9b, and three signals
for the dimer 9d [δ ϭ Ϫ78.2 (7%), Ϫ84.2 (7%), Ϫ144.4
(14%)]. The missing signal is likely to be superimposed with
the signal at δ ϭ Ϫ144.4. Furthermore, one signal of minor
intensity was observed at δ ϭ Ϫ146.9 (1%).
are shorter than the sum of the van der Waals radii of tin
and chlorine (3.97 A).[24] The Sn(1)ϪCl(2) and Sn(4)ϪCl(3)
˚
˚
bond lengths are 2.434(2) and 2.488(2) A (9), respectively,
˚
and 2.478(2) and 2.474(2) A (12), respectively, which are
slightly longer than the SnϪCl single bond length of 2.39
[22]
˚
A.
An equilibrium between tetrameric double ladder struc-
tures (n ϭ 4) and dimers (n ϭ 2) has been previously re-
ported for CHCl3 solutions of the tetramethylene-bridged
tetraorganodistannoxanes
{[R(Cl)Sn(CH2)4Sn(Cl)R]O}n
(13, R ϭ Me3SiCH2; 14, R ϭ Me3CCH2; 15, Me2CHCH2),
which showed degrees of association with n ϭ 3.9, 2.3, and
2.5, respectively.[18] The molecular mass determination of 9
in CHCl3 showed M ϭ 1639 g molϪ1 (c ϭ 20 mg mLϪ1),
which is indicative of the existence in solution of an equilib-
rium between double ladder structures (9a؊c) (calcd. for
9a؊c: M ϭ 2035 g molϪ1) and the dimer 9d (calcd. for 9d:
M ϭ 1018 g molϪ1) (Scheme 4). Compound 12 has a mo-
lecular mass M ϭ 1191 g molϪ1 (c ϭ 20 mg mLϪ1) in
CHCl3, showing that the dimer 12d (calcd. for 12d: M ϭ
1077 g molϪ1) dominates at this concentration (Scheme 4).
The molecular mass of 12 increases at higher concentration
(M ϭ 1689 g molϪ1, c ϭ 145 mg mLϪ1), showing that the
equilibrium is shifted towards formation of double ladders
12a؊c (calcd. for 12a؊c: M ϭ 2155 g molϪ1) (Scheme 5).
Table 2. 119Sn NMR spectroscopic data in CDCl3 for compounds
of
the
type
{[R(Cl)Sn(CH2)4Sn(Cl)R][RЈ(Cl)Sn(CH2)4Sn-
(Cl)RЈ]O2}2; chemical shifts are given in δ values and coupling con-
stants [2J(119SnϪOϪ119/117Sn)] in Hz
Snexo
Snendo
9
R ϭ Me3CCH2
Ϫ78.2 [74] 7% Ϫ144.4 [66] 14%
Ϫ84.2 [57] 7%
RЈ ϭ Me2CHCH2
Ϫ83.0 [61] 36% Ϫ145.2 [70] 35%
Ϫ146.9
5% Ϫ144.9
5%
1%
5%
12 R ϭ Me3CCH2
RЈ ϭ Me3SiCH2
Ϫ68.5
Ϫ83.8
Ϫ70.6
Ϫ85.6
1% Ϫ143.2
1%
2%
Ϫ84.5 [64] 27% Ϫ140.7 [64] 33%
Ϫ87.0 [60] 11% Ϫ139.5 [62] 10%
13 R ϭ RЈ ϭ Me3SiCH2
14 R ϭ RЈ ϭ Me3CCH2
Ϫ66.7
Ϫ83.1
Ϫ85.4
50% Ϫ137.3
25% Ϫ146.8
25% Ϫ147.3
50%
25%
25%
15 R ϭ RЈ ϭ Me2CHCH2 Ϫ78.7 [62] 8% Ϫ143.1 [70] 8%
Ϫ79.1 [66] 42% Ϫ144.8 [61] 42%
The 119Sn NMR spectrum of 12 in toluene shows two
pairs of signals of equal integral ratio at δ ϭ Ϫ83.8 (23%)/
Ϫ145.5 (23%) and at δ ϭ Ϫ86.9 (11%)/Ϫ144.3 (12%), which
are assigned with caution to the tetramers 12a and 12b
Scheme 4
156
Eur. J. Inorg. Chem. 2001, 153Ϫ160

Spacer-Bridged Tetraorganodistannoxanes
FULL PAPER
(Scheme 4). Furthermore, two sets of four signals are ob-
served at δ ϭ Ϫ68.8 (5%), Ϫ83.3 (5%), Ϫ146.2 (5%), and
Ϫ149.4 (5%) and at δ ϭ Ϫ71.3 (2%), Ϫ85.4 (3%), Ϫ143.0
(3%), and Ϫ147.9 (3%), which are assigned to the cis and
trans isomer of 12d (Scheme 4). The 119Sn NMR spectro-
scopic experiments of 12 in CDCl3 at concentrations of c ϭ
145 mg mLϪ1 and c ϭ 290 mg mLϪ1 gave similar results:
The tetramers 12a and 12b are characterized by two sets of
signals at Ϫ84.5 (27%)/Ϫ140.7 (33%) and at δ ϭ Ϫ87.0
(11%)/Ϫ139.5 (10%). It is most likely that the signal at δ ϭ
Ϫ140.7 is superimposed with two resonances of the corres-
ponding dimer. This assumption is supported by the obser-
vation of only six additional resonances at δ ϭ Ϫ68.5 (5%),
Ϫ70.6 (1%), Ϫ83.8 (5%), Ϫ85.6 (1%), Ϫ143.2 (2%), and
Ϫ144.9 (5%) for the cis and the trans isomer of the dimer
12d instead of the expected eight signals.
On the basis of the 119Sn NMR spectroscopic experi-
ments in CDCl3 at c ϭ 145 mg mLϪ1 the dimer/tetramer
ratio of 12 was estimated to be approximately 1:1, which is
in accordance with the molecular mass determination at the
same concentration. It is worth noting that signals of the
symmetrically substituted double ladders 13؊15 are not de-
Scheme 6. Reaction of the mixed tetramethylene-bridged tetraor-
ganodistannoxane 12 with the tetramethylene-bridged ditin tetra-
tected in the 119Sn NMR spectra of analytically pure 9 or chloride 10
12.
The structure of the double ladders can formally be di-
vided into a spacer-bridged organostannoxane core to
rically
substituted
double
ladders
Me3SiCH2; 14, R ϭ
{[R(Cl)Sn-
(CH2)4Sn(Cl)R]O}4 (13,
R
ϭ
which
two
spacer-bridged
ditin
tetrachlorides
Me3CCH2; 15, R ϭ Me2CHCH2) were not observed,
which, in accordance with the NMR spectroscopic experi-
ments discussed above, shows that there is no equilibrium
between mixed double ladders and symmetrically substi-
tuted double ladders. In the ESMS spectrum of 9 and 12,
additional cluster patterns are observed which are centered
at m/z ϭ 1032 and m/z ϭ 1105, respectively. These patterns
are assigned to doubly charged species such as [9a؊c ϩ 2
OH]2Ϫ (calcd. m/z ϭ 1034) and [9a؊c Ϫ Cl ϩ 3 OH]2Ϫ
(calcd. m/z ϭ 1025) and [12a؊c ϩ 2 OH]2Ϫ (calcd. m/z ϭ
1095) and [12a؊c ϩ 2 Cl]2Ϫ (calcd. m/z ϭ 1113), rather
than to the corresponding anions of the dimers 9d and 12d.
Nevertheless, we cannot exclude that the cluster patterns of
the latter are superimposed by the patterns of the doubly
charged species. There are also cluster patterns of low in-
tensity at m/z ϭ 531 and m/z ϭ 558 (9), and m/z ϭ 558 and
m/z ϭ 590 (12), which are consistent with the anions AϪC
(Scheme 7). The formation of AϪC can be explained by the
dissociation of the dimers 9d/12d and the complexation of
a chloride.
RCl2Sn(CH2)4SnCl2R are coordinated. The addition of
RCl2Sn(CH2)4SnCl2R (10, R ϭ Me3SiCH2) to a solution of
12 in a 1:1 molar ratio gave a partial exchange (Scheme 6).
The 119Sn NMR spectrum in CDCl3 shows the signals of
the starting materials RCl2Sn(CH2)4SnCl2R (10, R ϭ
Me3SiCH2) and 12, a resonance at δ ϭ Ϫ113.0 assigned to
RCl2Sn(CH2)4SnCl2R (3, R ϭ Me3CCH2), two resonances
at δ ϭ Ϫ67.7 and Ϫ138.4 assigned to the simple double
ladder 13, and additional resonances at δ ϭ Ϫ85.7, Ϫ100
(W1/2 ϭ 600 Hz), and Ϫ147 (W1/2 ϭ 600 Hz), for which no
assignment is made.
In the case of the trimethylene-bridged double ladder
{[R(Cl)Sn(CH2)3Sn(Cl)R]O}4 (R ϭ Me3SiCH2), no ex-
change was observed upon addition of a trimethylene-
bridged ditin tetrachloride RCl2Sn(CH2)3SnCl2R (R ϭ
Me3CCH2), which hints at the higher kinetic stability of
the former compound compared with the tetramethylene-
bridged double ladders.
The electrospray mass spectra of 9 and 12, in acetonitrile/
dichloromethane solution (9:1), show cluster patterns that
are consistent with the species formed by ionization of
dimers as well as of tetrameric double ladder compounds.
The negative ion ESMS spectrum of 9 shows a cluster pat-
tern which is centered at m/z ϭ 2040 and which is assigned
to the major species [9a؊c ϩ Cl]Ϫ (calcd. m/z ϭ 2071),
[9a؊c ϩ OH]Ϫ (calcd. m/z ϭ 2051), and [9a؊c Ϫ Cl ϩ 2
OH]Ϫ (calcd. m/z ϭ 2033). Compound 12 shows a similar
cluster pattern centered at m/z ϭ 2170 which is indicative
of the species [12a؊c ϩ Cl]Ϫ (calcd. m/z ϭ 2191), [12a؊c
Scheme 7
In the ESMS spectra of both 9 and 12, patterns of high
ϩ OH]Ϫ (calcd. m/z ϭ 2173), and [12a؊c Ϫ Cl ϩ 2 OH]Ϫ intensity were observed, which are assigned to the com-
(calcd. m/z ϭ 2153). Species corresponding to the symmet- plexes [RCl2Sn(CH2)4SnCl2R ϩ Cl]Ϫ (9, R ϭ Me3CCH2
Eur. J. Inorg. Chem. 2001, 153Ϫ160
157

K. Jurkschat, D. Dakternieks et al.
FULL PAPER
vaporization nozzle of the electrospray ion source at a flow rate
of 10 µL minϪ1. Nitrogen was used as both a drying gas and for
nebulization with flow rates of approximately 200 mL minϪ1 and
20 mL minϪ1, respectively. Pressure in the mass analyzer region was
usually about 4·10Ϫ5 mbar. Typically, 50 signal-averaged spectra
were collected.
with m/z ϭ 613, Me2CHCH2 with m/z ϭ 585; 12, R ϭ
Me3CCH2 with m/z ϭ 613, Me3SiCH2 with m/z ϭ 645).
This observation is in agreement with the NMR spectro-
scopic experiment showing partial exchange of the tetra-
chloride fragment RCl2Sn(CH2)4SnCl2R (3,
R
ϭ
Me3CCH2) in 12 upon addition of RCl2Sn(CH2)4SnCl2R
(10, R ϭ Me3SiCH2) to a CHCl3 solution of 12 (Scheme 6).
Synthesis of (Me3SiCH2)Cl2Sn(CH2)3SnCl2Ph (6): To a solution of
hexaphenyldistannane (2.00 g, 2.86 mmol) and naphthalene
(100 mg, 1.28 mmol) in THF (30 mL), sodium (0.14 g, 6.09 mmol)
was added in small portions. After stirring the resulting solution
for 18 h, a solution of (3-chloropropyl)diphenyl(trimethylsilylme-
thyl)tin (2) (1.25 g, 2.86 mmol) in THF (10 mL) was added drop-
wise at Ϫ50 °C. The resulting suspension was stirred for 48 h dur-
ing which time it was warmed up. The resulting solid material was
filtered. After evaporation of the solvent, the resulting crude oily
product was dissolved in hot hexane (5 mL) and the solid material
was filtered. The solvent was removed in vacuo, giving 2.99 g
1-[diphenyl(trimethylsilylmethyl)stannyl]-3-(triphenylstannyl)-
Conclusion
The synthesis of a mixed double ladder starting from the
unsymmetrically substituted (Me3SiCH2)Cl2Sn(CH2)3-
SnCl2Ph (6) failed. However, two convenient synthetic
methods for the preparation of the first mixed double lad-
ders
{[R(Cl)Sn(CH2)4Sn(Cl)R][RЈ(Cl)Sn(CH2)4Sn(Cl)-
propane (5) as
a yellow oil {
119Sn NMR (CHCl3/CDCl3,
RЈ]O2}2 (9, R ϭ Me3CCH2, RЈ ϭ Me2CHCH2; 12, R ϭ
Me3CCH2, RЈ ϭ Me3SiCH2) and their characterization by
X-ray crystallography are given. In contrast to the previ-
ously reported trimethylene-bridged double ladders, the
tetramethylene-bridged species are kinetically labile in solu-
tion and mixed double ladders are formed by scrambling
reactions between the related simple double ladders. Fur-
thermore, the mixed tetramethylene-bridged species seem to
be thermodynamically more stable than the related simple
species, since no simple double ladders were detected after
the quantitative formation of the mixed double ladder com-
pounds. Nevertheless, the partial substitution of fragments
such as RCl2Sn(CH2)4SnCl2R in the mixed double ladders
is possible. These observations give an explanation for the
fact that tetramethylene-bridged organostannoxanes are
more efficient catalysts in transesterification reactions than
the trimethylene-bridged analogues.[18] This work is a fur-
ther step toward the fine tuned catalyst design of spacer-
bridged distannoxanes.
111.92 MHz): δ ϭ Ϫ63.5 [4J(119SnϪ117/119Sn) ϭ 56 Hz], Ϫ103.9
[4J(119SnϪ117/119Sn) ϭ 54 Hz]}. The intermediate product 5 was
dissolved in acetone (20 mL) and a solution of HgCl2 (4.32 g,
15.88 mmol) in acetone (20 mL) was added dropwise at 0 °C. The
suspension was stirred overnight and filtered. The solvent was re-
moved in vacuo giving an oily residue, which was suspended in
diethyl ether (50 mL). Again, it was filtered and the solvent was
evaporated. The resulting solid residue was extracted with hexane
(40 mL) in a Soxhlet apparatus for 72 h, giving 1.77 g (53%) of 6
as a beige solid with a m.p. of 74Ϫ75 °C. Ϫ 1H NMR (400.13 MHz,
CDCl3): δ ϭ 0.17 (s, 9 H, SiMe3), 0.88 [s, 2 H, SiCH2,
2J(119SnϪ1H) ϭ 93 Hz], 1.83 (t, 2 H, SnCH2), 2.07 (t, 2 H, SnCH2),
2.39 (quint, 2 H, CH2), 7.48Ϫ7.63 (m, 5 H, HPh). Ϫ 13C NMR
(CDCl3, 100.63 MHz): δ ϭ 1.0 (SiMe3), 11.9 [1J(13CϪ119Sn) ϭ
226 Hz, CH2Si], 20.9 (CH2), 27.6 [1J(13CϪ119Sn) ϭ 369 Hz,
CH2Sn], 29.2 [1J(13CϪ119Sn)
ϭ
331 Hz, CH2Sn], 129.6
[3J(13CϪ119Sn) ϭ 60 Hz, Cm], 131.7 [4J(13CϪ119Sn) ϭ 27 Hz, Cp],
134.6 [2J(13CϪ119Sn) ϭ 48 Hz, Co], 138.6 [1J(13CϪ119Sn) ϭ 598 Hz,
Ci]. Ϫ 119Sn NMR (111.92 MHz, CHCl3/CDCl3): δ ϭ 38.2
[4J(119SnϪ117/119Sn)
ϭ ϭ
158 Hz], 130.0 [4J(119SnϪ117/119Sn)
159 Hz]. Ϫ C13H22Cl4SiSn2 (585.7): calcd. C 26.66, H 3.79; found
C 26.30, H 3.80.
Reaction of (Me3SiCH2)Cl2Sn(CH2)3SnCl2Ph (6) with (tBu2SnO)3
(NMR Spectroscopic Experiment): (tBu2SnO)3 (140 mg, 0.56 mmol)
was added to a solution of (Me3SiCH2)Cl2Sn(CH2)3SnCl2Ph (6)
(330 mg, 0.56 mmol) in CH2Cl2 (3 mL). The resulting solution was
heated at reflux for 5 min. The solvent was evaporated, the residue
washed with pentane (5 mL) and dissolved in CH2Cl2 (2.5 mL). A
119Sn NMR spectrum of this solution was measured. Ϫ 119Sn
NMR (111.91 MHz, CH2Cl2/D2Ocapillary) δ ϭ Ϫ53.7 (tBu2SnCl2),
Ϫ84.5 [2J(119SnϪ117/119Sn) ϭ 73 Hz], Ϫ86.4 [2J(119SnϪ117/119Sn) ϭ
75 Hz], Ϫ90.8 [2J(119SnϪ117/119Sn) ϭ 73 Hz], Ϫ92.2 [2J(119SnϪ
117/119Sn) ϭ 72 Hz], Ϫ94.2, Ϫ96.2 [2J(119SnϪ117/119Sn) ϭ 60 Hz],
Experimental Section
General Remarks: All solvents were dried and purified by standard
procedures. Ϫ Bruker DPX-300 and DRX-400 spectrometers were
used to obtain 1H and 119Sn NMR spectra. H and 119Sn chemical
1
shifts δ are given in ppm and were referenced against Me4Si and
Me4Sn, respectively. No integration of the signals in the H NMR
spectra is given as a result of their partial superimposition. Ϫ Mo-
lecular mass determinations were performed with a Knaur osmo-
1
meter in CHCl3 at 59 °C.
Ϫ The organotin chlorides
Ϫ100.2 [2J(119SnϪ117/119Sn)
ϭ
62 Hz], Ϫ132.1 [2J(119SnϪ
RCl2Sn(CH2)4SnCl2R (3, R ϭ Me3CCH2; 4, R ϭ Me2CHCH2; 10,
R ϭ Me3SiCH2) and oxides [R(O)Sn(CH2)4Sn(O)2R]n (8, R ϭ
Me3CCH2; 7, R ϭ Me2CHCH2; 11, R ϭ Me3SiCH2) were prepared
according to literature procedures.[18] Ϫ Electrospray mass spectra
were obtained with a Platform II single quadrupole mass spectro-
meter (Micromass, Altrincham, UK) using an acetonitrile/dichloro-
methane (9:1) mobile phase. Acetonitrile/dichloromethane solu-
tions (0.1 m) of the compounds were injected directly into the
spectrometer using a Rheodyne injector equipped with a 100 µL
loop. A Harvard 22 syringe pump delivered the solutions to the
117/119Sn) ϭ 71 Hz], Ϫ132.3, Ϫ132.5 [2J(119SnϪ117/119Sn) ϭ 72 Hz],
Ϫ134.5 [2J(119SnϪ117/119Sn)
ϭ
68 Hz], Ϫ137.6 [2J(119SnϪ
117/119Sn) ϭ 63 Hz], Ϫ164.1, Ϫ165.4, Ϫ166.2, Ϫ168.5 [2J(119SnϪ
117/119Sn) ϭ 78 Hz], Ϫ170.5, Ϫ209.5, Ϫ209.7, Ϫ210.9 [2J(119SnϪ
117/119Sn) ϭ 83 Hz], Ϫ212.2 [2J(119SnϪ117/119Sn) ϭ 88 Hz], Ϫ214.0
[2J(119SnϪ117/119Sn)
ϭ ϭ
73 Hz], Ϫ214.9 [2J(119SnϪ117/119Sn)
82 Hz].
[Synthesis of {[R(Cl)Sn(CH2)4Sn(Cl)R]2[RЈ(Cl)Sn(CH2)4Sn(Cl)-
RЈ]2O2}2 (9, R ؍ Me3CCH2, RЈ ؍ Me2CHCH2). ؊ Method A:
158
Eur. J. Inorg. Chem. 2001, 153Ϫ160

Spacer-Bridged Tetraorganodistannoxanes
[R(O)Sn(CH2)4Sn(O)R]n (R ϭ Me2CHCH2) (100 mg, 0.23 mmol) (CHCl3, 20 mg mLϪ1): 1639 g molϪ1. Ϫ C52H112Cl8O4Sn8 (2035.0):
FULL PAPER
was added to a solution of RCl2Sn(CH2)4SnCl2R (R ϭ Me3CCH2)
(131 mg, 0.23 mmol) in toluene (25 mL) at room temperature. The
resulting suspension was stirred at room temperature for 1 h and
heated at reflux for 2 h until the solution became clear. Crystalliza-
calcd. C 30.69, H 5.55; found calcd. C 30.61, H 5.58%.
Synthesis of {[R(Cl)Sn(CH2)4Sn(Cl)R]2[RЈ(Cl)Sn(CH2)4Sn(Cl)-
RЈ]2O2}2 (12, R ؍ Me3CCH2, RЈ ؍ Me3SiCH2). ؊ Method A: In
tion from toluene at room temperature yielded 218 mg (94%) of 9 a similar manner to compound 9 the distannoxane 12 was prepared
as colorless crystals with m.p. 214Ϫ216 °C. Method B: from RCl2Sn(CH2)4SnCl2R (R ϭ Me3CCH2) (347 mg, 0.60 mmol)
[R(O)Sn(CH2)4Sn(O)2R]n (R ϭ Me3CCH2) (100 mg, 0.21 mmol) and [R(O)Sn(CH2)4Sn(O)R]n (R Me3SiCH2) (300 mg,
Ϫ
ϭ
was added to
a
solution of RCl2Sn(CH2)4SnCl2R (R
ϭ
0.60 mmol), and obtained as a colorless solid (0.62 g, 96%) with
m.p. 197Ϫ198 °C. Ϫ Method B: Analogously the reaction of
RCl2Sn(CH2)4SnCl2R (R ϭ Me3SiCH2) (456 mg, 0.75 mmol) and
[R(O)Sn(CH2)4Sn(O)R]n (R ϭ Me3CCH2) (350 mg, 0.75 mmol)
gave 12 as a colorless solid (0.79 g, 98%). Ϫ Method C (NMR Spec-
troscopic Experiment): {[R(Cl)Sn(CH2)4Sn(Cl)R]O}4 (13, R ϭ
Me2CHCH2) (117 mg, 0.21 mmol) in toluene (25 mL) at room tem-
perature. The resulting suspension was stirred at room temperature
for 1 h and heated at reflux for 2 h until the solution became clear.
Crystallization from toluene at room temperature yielded 203 mg
(94%) of 9 as colorless crystals with m.p. 214Ϫ216 °C. Ϫ Method
C
(in situ Preparation, NMR Spectroscopic Experiment): Me3SiCH2) (53 mg, 0.24 mmol) was added to a solution of
{[R(Cl)Sn(CH2)4Sn(Cl)R]O}4 (15,
0.24 mmol) was added
{[R(Cl)Sn(CH2)4Sn(Cl)R]O}4 (14,
R
to
R
ϭ
Me2CHCH2) (53 mg, {[R(Cl)Sn(CH2)4Sn(Cl)R]O}4 (14,
R ϭ Me3CCH2) (50 mg,
a
solution of 0.24 mmol) in CDCl3 (2 mL), and the resulting solution was heated
ϭ
Me3CCH2) (50 mg, at reflux for 3 d. 119Sn NMR spectra of this solution were recorded
0.24 mmol) in CDCl3 (2 mL), and the resulting solution was heated
after t ϭ 1 h, 1 d, and 3 d. Ϫ 119Sn NMR (149.21 MHz, CDCl3):
δ ϭ Ϫ68.5 (5%), Ϫ70.6 (1%), Ϫ83.8 (5%), Ϫ84.5 (27%), Ϫ85.6
at reflux for 3 d. A 119Sn NMR spectrum of this solution was re-
corded after t ϭ 4 d. Ϫ 119Sn NMR (149.21 MHz, CDCl3) δ ϭ (1%), Ϫ87.0 (11%), Ϫ139.5 (10%), Ϫ140.7 (33%), Ϫ143.2 (2%),
Ϫ78.2 [2J(119SnϪ117/119Sn) ϭ 74 Hz, 7%], Ϫ83.0 [2J(119SnϪ117/
119Sn) ϭ 61 Hz, 36%], Ϫ84.2 [2J(119SnϪ117/119Sn) ϭ 57 Hz, 7%], Ϫ68.8 (5%), Ϫ71.3 (2%), Ϫ83.3 [2J(119SnϪ117/119Sn) ϭ 67 Hz, 5%],
Ϫ144.4 [2J(119SnϪ117/119Sn) ϭ 66 Hz, 14%], Ϫ145.2 [2J(119SnϪ117/ Ϫ83.8 [2J(119SnϪ117/119Sn) ϭ 66 Hz, 23%], Ϫ85.4(3%), Ϫ86.9
Ϫ144.9 (5%). Ϫ 119Sn NMR (111.92 MHz, toluene, D2O cap.): δ ϭ
119Sn) ϭ 70 Hz, 35%], Ϫ146.9 (1%). Ϫ 119Sn NMR (111.92 MHz, [2J(119SnϪ117/119Sn)
ϭ 66 Hz, 11%], Ϫ143.0 (3%), Ϫ144.3
toluene/D2O cap.): δ ϭ Ϫ78.7 [2J(119SnϪ117/119Sn) ϭ 67 Hz, 5%],
Ϫ85.2 [2J(119SnϪ117/119Sn) ϭ 65 Hz, 26%], Ϫ85.4 (4%), Ϫ86.4
[2J(119SnϪ117/119Sn) ϭ 65 Hz, 15%], Ϫ147.9 [2J(119SnϪ117/119Sn) ϭ
[2J(119SnϪ117/119Sn) ϭ 66 Hz, 12%], Ϫ145.5 [2J(119SnϪ117/119Sn) ϭ
67 Hz, 23%], Ϫ146.2 [2J(119SnϪ117/119Sn) ϭ 67 Hz, 5%], Ϫ147.9
(3%), Ϫ149.4 [2J(119SnϪ117/119Sn) ϭ 67 Hz, 5%]. Ϫ 1H NMR
66 Hz, 15%], Ϫ148.5 [2J(119SnϪ117/119Sn) ϭ 67 Hz, 27%], Ϫ150.2 (400.13 MHz, [D8]toluene): δ ϭ 0.21 (s, Me3Si), 0.22 (s, Me3Si),
(5%), Ϫ152.7 (3%). Ϫ 1H NMR (400.13 MHz, C6D6): δ ϭ 1.04 (d,
0.41 (s, Me3Si), 1.08 (s, Me3C), 1.11 (s, CH2Si), 1.15 (s, Me3C), 1.19
Me2CH), 1.16 (s, Me3C), 1.17 (s, Me3C), 1.23 (d, Me2CH), 1.24 (d,
(s, CH2Si), 1.34 (s, Me3C), 1.36 (s, CH2Si), 1.85Ϫ2.21 (complex
Me2CH), 1.40 (s, Me3C), 1.90Ϫ2.42 (complex pattern, CH2), 2.47 pattern, CH2). Ϫ Molecular mass determination (CHCl3, 20 mg
(m, Me2CH), 2.76 (m, Me2CH). Ϫ Molecular mass determination
mLϪ1): 1191 g molϪ1, (CHCl3, 145 mg mLϪ1): 1689 g molϪ1. Ϫ
Table 3. Crystallographic data for 9 and 12
9
12
Empirical formula
Formula mass
Crystal system
Crystal size [mm]
Space group
C52H112Cl8O4Sn8
C52H120Cl8O4Si4Sn8·C6H6
2233.07
2034.54
triclinic
triclinic
0.20 ϫ 0.20 ϫ 0.20
0.30 ϫ 0.25 ϫ 0.20
¯
¯
P1
P1
˚
a [A]
10.996(1)
12.247(1)
16.807(1)
69.019(1)
87.145(1)
65.013(1)
1901.7(3)
1
12.746(1)
13.529(1)
16.117(1)
79.424(1)
69.207(1)
62.388(1)
2301.7(3)
1
˚
b [A]
˚
c [A]
α [°]
β [°]
γ [°]
3
˚
V [A ]
Z
ρcalcd. [Mg/m3]
1.777
1.611
µ [mmϪ1
F(000)
]
2.898
2.451
992
1098
θ range [°]
2.98 to 25.68
Ϫ13 Յ h Յ 13
Ϫ12 Յ k Յ 14
Ϫ20 Յ l Յ 20
18520
3.16 to 25.37
Ϫ12 Յ h Յ 12
Ϫ13 Յ k Յ 16
Ϫ18 Յ l Յ 19
26367
Index ranges
No. of reflns. collected
Completeness to θmax
no. of independent reflns./Rint
no. of reflns. observed
with [I Ͼ 2σ(I)]
85.3
6156/0.0580
2780
92.3
7805/0.0260
3885
no. of refined param.
335
406
GooF (F2)
0.822
0.939
R1 (F) [I Ͼ 2 σ(I)]
wR2 (F2) (all data)
(∆/σ)max
0.0431
0.0371
0.1312
0.1021
Ͻ 0.001
0.714/Ϫ0.776
Ͻ 0.001
0.539/Ϫ0.484
3
˚
Largest diff peak/hole [e/A ]
Eur. J. Inorg. Chem. 2001, 153Ϫ160
159

K. Jurkschat, D. Dakternieks et al.
FULL PAPER
C52H120Cl8O4Si4Sn8 (2155.4): calcd. C 28.98, H 5.61; found calcd.
C 29.35, H 5.45.
12 Union Road, Cambridge CB21EZ, UK [Fax: (internat.)
ϩ 44-1223/336-033; E-mail: deposit@ccdc.cam.ac.uk].
Acknowledgments
We thank the Deutsche Forschungsgemeinschaft, the Fonds der
Chemischen Industrie and the Australian Research Council (ARC)
for financial support.
Reaction of {[R(Cl)Sn(CH2)4Sn(Cl)R]2[RЈ(Cl)Sn(CH2)4Sn(Cl)-
RЈ]2O2}2 (12,
R
؍
Me3CCH2, RЈ
؍
Me3SiCH2) with
RCl2Sn(CH2)4SnCl2R (3, R ؍ Me3CCH2) (NMR Spectroscopic Ex-
periment): Compound 3 (72 mg, 0.34 mmol) was added to a solu-
tion of 12 (72 mg, 0.34 mmol) in CDCl3 (2 mL). The resulting solu-
tion was heated at reflux for 3 h and a 119Sn NMR spectrum was
recorded. Ϫ 119Sn NMR (149.21 MHz, CDCl3): δ ϭ Ϫ131.4,
Ϫ113.0, Ϫ66.7, Ϫ67.5, Ϫ69.7, Ϫ82.9, Ϫ 83.5, Ϫ84.7, Ϫ85.3,
Ϫ86.1, Ϫ100 (W1/2 ϭ 600 Hz), Ϫ137.4, Ϫ138.5, Ϫ139.6, Ϫ142.4,
Ϫ144.8, Ϫ147 (W1/2 ϭ 600).
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Addition of RCl2Sn(CH2)3SnCl2R (R ؍ Me3CCH2) to a Solution of
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scopic Experiment): RCl2Sn(CH2)3SnCl2R (R
ϭ Me3CCH2)
(56 mg, 0.10 mmol) was added to a solution of the double ladder
(216 mg, 0.10 mmol) in CH2Cl2 (3 mL). The resulting solution was
heated at reflux for 2 h and a 119Sn NMR spectrum (149.21 MHz,
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starting materials at δ ϭ Ϫ96.1 [2J(119SnϪ117/119Sn) ϭ 67 Hz],
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[11]
[12]
Ϫ132.9 [2J(119SnϪ117/119Sn)
[RCl2Sn(CH2)3SnCl2R, R ϭ Me3CCH2].
ϭ
69 Hz] and
δ
ϭ
107.9
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from benzene were collected with a Nonius KappaCCD diffracto-
˚
meter with graphite-monochromated Mo-Kα (0.71069 A) radiation
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at 291 K. The data collection covered almost the whole sphere of
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Crystal decay was monitored by repeating the initial frames at the
end of data collection. On analysis of the duplicate reflections,
there was no indication for any decay. The data were not corrected
for absorption effects. The structure was solved by direct methods
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syntheses. Refinement applied full-matrix least-squares methods
SHELXL97[26] (Sheldrick, 1997). Ϫ The H atoms were placed in
geometrically calculated positions using a riding model (CϪHprim.
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Bruker AXS, Inc., Madison, Wisconsin, USA, 1997.
Received May 26, 2000
[17]
[18]
[19]
[20]
[21]
[22]
˚
˚
0.96 A, CϪHsec. 0.97 A; Haryl CϪH 0.93), and for 9 refined with a
2
˚
common isotropic temperature factor [Uiso 0.148(7) A ] and for 12
with isotropic temperature factors constrained to be 1.5 times those
of the carrier atom. Ϫ Disordered tetramethylene, tert-butyl (12),
and isobutyl (9) groups were found with occupancies of 0.3333
[C(43Ј), C(44Ј)], 0.5 [C(3), C(5), C(3Ј), C(5Ј)], and 0.6666 [C(43),
C(44)] in 12 and of 0.15 [C(32Ј)] and 0.85 [C(32)] in 9. Ϫ Atomic
scattering factors for neutral atoms and real and imaginary disper-
sion terms were taken from International Tables for X-ray Crystal-
lography.[27] The figures were created by SHELXTL[28] (Sheldrick,
1991). Crystallographic data are given in Table 3 and selected bond
lengths and angles in Table 1. Crystallographic data for the struc-
tures reported in this paper have been deposited with the Cam-
bridge Crystallographic Data Centre as supplementary publica-
tions nos. CCDC-144264 (9) and CCDC-144265 (12). Copies of
the data can be obtained free of charge on application to CCDC,
[23]
[24]
[25]
[26]
[27]
[28]
[I00217]
160
Eur. J. Inorg. Chem. 2001, 153Ϫ160