Generation and reactions of overcrowded diaryldilithiostannane and diaryldipotassiostannane

Article abstract of DOI:10.1002/ejic.200500375

Exhaustive reduction of an overcrowded dibromostannane bearing two bulky aromatic substituents, Tbt(Dip)SnBr₂ {Tbt = 2,4,6- tris[bis(trimethylsilyl)methyl]phenyl; Dip = 2,6-diisopropylphenyl}, with an excess amount of lithium naphthalenide in THF at -78°C gave the corresponding dilithiostannane, Tbt(Dip)SnLi₂, the generation of which was confirmed by trapping experiments with some electrophiles together with ¹¹⁹Sn and ⁷Li NMR spectroscopy. The diaryldilithiostannane was found to be stable in solution under an inert gas below -25°C. The potassium analogue, Tbt(Dip)-SnK₂, was also generated by the reduction of the dibromostannane in THF at -78°C by the use of KC₈ as a reductant. The reactions of dilithiostannane and dipotassiostannane obtained with o-dibromobenzene did not give a stannacyclopropabenzene derivative but an unexpected cyclization product, a stannacyclobutabenzene derivative, in contrast to the reactions of the corresponding dilithiosilane and dilithiogermane, Tbt(Dip)ELi₂ (E = Si, Ge), with o-dibromobenzene leading to the formation of the corresponding metallacyclopropabenzenes as stable crystalline compounds. A preliminary result of the synthesis of a tin-tellurium double-bond compound from the dilithiostannane is also presented. Wiley-VCH Verlag GmbH & Co. KGaA, 2005.

Full text of DOI:10.1002/ejic.200500375

FULL PAPER
Generation and Reactions of Overcrowded Diaryldilithiostannane and
Diaryldipotassiostannane
Tomoyuki Tajima,[a] Nobuhiro Takeda,[a] Takahiro Sasamori,[a] and Norihiro Tokitoh*[a]
Keywords: Group 14 elements / Tin / Anions / Lithium / Potassium / Solid-state structures
Exhaustive reduction of an overcrowded dibromostannane
bearing two bulky aromatic substituents, Tbt(Dip)SnBr2 {Tbt
The reactions of dilithiostannane and dipotassiostannane ob-
tained with o-dibromobenzene did not give a stannacyclo-
propabenzene derivative but an unexpected cyclization prod-
uct, a stannacyclobutabenzene derivative, in contrast to the
reactions of the corresponding dilithiosilane and dilithio-
germane, Tbt(Dip)ELi2 (E = Si, Ge), with o-dibromobenzene
leading to the formation of the corresponding metallacyclo-
propabenzenes as stable crystalline compounds. A prelimi-
nary result of the synthesis of a tin–tellurium double-bond
compound from the dilithiostannane is also presented.
(© Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim,
Germany, 2005)
=
2,4,6-tris[bis(trimethylsilyl)methyl]phenyl; Dip
=
2,6-
diisopropylphenyl}, with an excess amount of lithium naph-
thalenide in THF at –78 °C gave the corresponding dilithio-
stannane, Tbt(Dip)SnLi2, the generation of which was con-
firmed by trapping experiments with some electrophiles to-
gether with 119Sn and 7Li NMR spectroscopy. The diaryldi-
lithiostannane was found to be stable in solution under an
inert gas below –25 °C. The potassium analogue, Tbt(Dip)-
SnK2, was also generated by the reduction of the dibromo-
stannane in THF at –78 °C by the use of KC8 as a reductant.
thesis and isolation of the first stable sila-[9] and germacy-
clopropabenzenes,[10] 2a and 2b, by reactions of the corre-
sponding overcrowded dilithiosilane 1a[11] and dilithiogerm-
ane 1b[2g,10] with o-dibromobenzene, respectively. Although
there have been many reports on the syntheses and charac-
terization of Si- and Ge-containing three-membered ring
compounds, investigations of their tin analogues, stannacy-
clopropanes and stannacyclopropenes,[8] are quite rare. To
the best of our knowledge, only one report has so far ap-
peared on the synthesis of stannacyclopropenes.[8c]
In this article, we report the generation of overcrowded,
diaryl-substituted dilithiostannane and dipotassiostannane
together with their attempted applications to the synthesis
of a hitherto unknown stannacyclopropabenzene 2c and a
tin–tellurium double-bond compound,[12] stannanetellone
(Scheme 1).
Introduction
One of the most important classes of organometallic
compounds is probably that of organolithium compounds,
which are now recognized as very powerful synthetic tools
in organic chemistry. Among them, the chemistry of lithium
compounds of heavier group 14 elements has attracted con-
siderable interest in recent years,[1] and some dilithiosilane
and dilithiogermane derivatives have been structurally char-
acterized and successfully applied to the construction of
novel bondings and/or structures of heavier group 14 ele-
ments.[2] By contrast, there are very few reports on tin di-
anion species. Saito and his co-workers have recently re-
ported the spectroscopic observation of a stannole di-
anion.[3] Although Schmidt et al. have proposed the forma-
tion of (C6H5)2SnLi2 in the reaction of (C6H5)2SnCl2 with
4 molar amounts of Li,[4,5] the yields of the trapping reac-
tions are not high and the generation of dilithiodiphenyl-
stannane was not evidenced by 119Sn and Li NMR spec-
7
troscopy. More recently, Egorov et al. reported the 119Sn
and 13C NMR studies of Et2SnLi2 and (C6H5)2SnLi2.[6] The
chemistry of tin-dianion species has recently gained more
and more attention.
Meanwhile, the study of three-membered ring com-
pounds containing a heavier group 14 element is one of
the most fascinating research areas in main group element
chemistry.[7,8] Recently, we have also succeeded in the syn-
[a] Institute for Chemical Research, Kyoto University,
Gokasho, Uji, Kyoto 611-0011, Japan
Fax: +81-774-38-3209
Scheme 1. Synthesis of metallacyclopropabenzenes using dianion
species of group 14 elements.
E-mail: tokitoh@boc.kuicr.kyoto-u.ac.jp
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DOI: 10.1002/ejic.200500375
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4291

T. Tajima, N. Takeda, T. Sasamori, N. Tokitoh
FULL PAPER
Tbt and Dip groups on the silicon and germanium atoms,
respectively. The thermal stability of 1a and 1b in THF
solutions has been investigated by the trapping experiments
using D2O, which revealed that dilithiosilane 1a was stable
below –78 °C and dilithiogermane 1b was stable below
–25 °C. When the solutions of 1a and 1b were warmed
above these temperatures, they underwent intramolecular
proton abstraction from one of the o-CH(SiMe3)2 units of
the Tbt group to give the corresponding lithium migration
products 6a and 6b, respectively (Scheme 4).[10,11] Treatment
of the intermediates such as 6a and 6b with D2O afforded
7a and 7b, respectively. Similarly, thermal stability of 1c was
studied by the trapping reactions using MeI at various tem-
peratures. The isolated yields of 5 in these reactions were
97% at –78 °C, 97% at –25 °C, and 45% at 0 °C, suggesting
that dilithiostannane 1c could be stable at least below
–25 °C.
Results and Discussion
Dibromostannane 4 was prepared by a method similar
to that for the synthesis of Tbt(Mes)SnBr2,[13] as shown in
Scheme 2. Tbt-substituted trihalostannane was synthesized
by the reaction of SnCl4 with TbtLi. Tbt- and Dip-substi-
tuted stannane, Tbt(Dip)SnH2 (3), was prepared by the nu-
cleophilic displacement reaction of the Tbt-substituted tri-
halostannane using DipMgBr, followed by reduction with
LiAlH4. Bromination reaction of 3 using Br2 in ether af-
forded the corresponding dibromostannane 4.
Scheme 2. Synthesis of dibromostannane 4.
Tbt(Dip)SnLi2 (1c) was generated by the exhaustive re-
duction of the overcrowded diaryldibromostannane 4 with
an excess amount of lithium naphthalenide (5 equiv.) in dry
THF at –78 °C under argon. The reaction mixture was
stirred at the same temperature for 1 h, and then treated
with an excess amount of MeI to afford Tbt(Dip)SnMe2 (5)
in 96% yield. The addition of DCl to the solution of 1c at
–78 °C resulted in the formation of Tbt(Dip)SnD2 (3a) in
96% yield (D content: 93%) (Scheme 3). The formation of
3a and 5 in the trapping experiments in high yields is most
likely interpreted in terms of the almost quantitative gener-
ation of dilithiostannane 1c as a stable compound in THF
at –78 °C.
Scheme 4. Stability of 1a, 1b, and 1c.
Trapping reactions of the decomposed compound from
1c were performed. Treatment of the THF solution of 1c
with 2,3-dimethyl-1,3-butadiene at room temperature fol-
lowed by the addition of MeI afforded TbtH and 9
(Scheme 4). The trapping experiment and the 119Sn NMR
studies suggest that dilithiostannane 1c is initially formed
and then it undergoes an intramolecular lithium migration
reaction giving a lithium-migrated compound 6c as in the
case of 6a and 6b. However, the stability of 6c is considered
to be different from that of 6a and 6b. The formation of 9
Scheme 3. Generation of overcrowded dilithiostannane 1c and di-
potassiostannane 1d.
The 119Sn NMR spectrum of 1c in THF at –80 °C strongly indicates that stannylene 8 is generated from 6c by
showed a broad signal at δ = –362.2 ppm, which is observed the elimination of LiH.
at a much higher field than that of Tbt(Dip)SnBr2 (4: δ =
The reduction of 4 was alternatively performed with KC8
–162.0 ppm in THF at –80 °C).[14] In the Li NMR spec- in THF at –110 °C to give the corresponding dipotassio-
trum, only one singlet signal was observed at δ = 0.6 ppm, stannane 1d, the generation of which was confirmed by the
suggesting the rapid exchange of lithium cations between 1c trapping experiment with MeI, giving 5 in 93% yield
and LiBr. After the NMR sample was left at room tempera- (Scheme 3). Dianion species 1d was unstable at higher tem-
ture for a few days, the remeasurement of the 119Sn NMR peratures, and its purple solution in THF rapidly turned
spectrum was performed. The 119Sn NMR signal of 1c dis- yellow at room temperature within a few minutes. The ad-
appeared and a new signal appeared at 1856.8 ppm, the dition of H2O to the yellow solution resulted in the forma-
chemical shift of which is close to those of stannylene spe- tion of TbtH, DipH, and 10[17] (Scheme 5). As this 1,3-sili-
7
cies reported so far.[16]
con rearrangement product 10 was reportedly obtained
Meanwhile, we have already succeeded in the generation from TbtLi above –30 °C in THF,[20] these results strongly
of dilithiosilane 1a[11] and dilithiogermane 1b[2g,10] bearing suggest the initial formation of TbtK and DipK at low tem-
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Diaryldilithiostannane and Diaryldipotassiostannane
FULL PAPER
perature in this reaction. Although we attempted the reac-
tions of 4 with other reductants (Li, K, tBuLi, and nBuLi),
the generation of the corresponding dianion species (1c or
1d) was not confirmed.
Figure 1. ORTEP drawing of 11 (50% probability). Hydrogen
atoms are omitted for clarity. Selected bond lengths [Å] and angles
[°]: Sn1–C1 2.144(4), Sn1–C7 2.205(4), C7–C6 1.522(6), C1–C2
1.398(6), C2–C3 1.397(6), C3–C4 1.411(6), C4–C5 1.402(6), C5–
C6 1.379(6), C6–C1 1.407(6), C1–Sn1–C7 67.62(16), Sn1–C7–C6
87.2(3), C1–C6–C7 114.4(4), Sn1–C1–C6 92.6(3), C1–C2–C3
117.8(4), C2–C3–C4 122.5(4), C3–C4–C5 118.0(4), C4–C5–C6
120.3(4), C5–C6–C1 121.0(4), C6–C1–C2 120.3(4).
Scheme 5. Stability of 1d.
With the evidence for the formation of dilithiostannane
1c and dipotassiostannane 1d in hand, we next attempted
the synthesis of stannacyclopropabenzene 2c by the method
similar to those for the syntheses of 2a[9] and 2b.[10] How-
ever, the reactions of 1c or 1d with o-dibromobenzene gave
an unexpected cyclic compound 11 as stable colorless crys-
tals (16% yield from 1c and 26% yield from 1d) instead of
the expected product 2c (Scheme 6). The structure of the
cyclic product 11 was satisfactorily confirmed by mass spec-
trometry, elemental analysis, and NMR spectroscopy, and
the molecular structure of 11 was finally determined by X-
ray crystallographic analysis. In Figure 1 the ORTEP draw-
ing of stannacyclobutabenzene 11 is shown.[18] The defor-
mation from the normal sp2 configuration is larger on the
C1 atom than the C6 atom, as judged by the bond angles
of Sn1–C1–C6 [92.6(3)°] and C1–C6–C7 [114.4(4)°]. Ad-
ditionally, the bond lengths of Sn1–C1 [2.144(4) Å] and C7–
C6 [1.522(6) Å] are slightly shorter than those reported
for stannabutabenzene [Sn1–C1 2.185(5) Å, C7–C6
1.588(8) Å].[18] All carbon–carbon bond lengths in the cen-
tral benzene ring of 11 are almost equal.
Tbt(Dip)SnMBr (M = Li, K) (12) and 1-bromo-2-metalla-
benzene by the M–Br exchange reaction, and then the re-
sulting 12 adds to benzyne generated from 1-bromo-2-
metallabenzene to afford the o-stannylated phenyl anion 13.
The intermediacy of 13 in these reactions is strongly sup-
ported by the fact that a small amount of Tbt(Dip)-
SnBr(Ph) (14; 6%) was obtained along with 11 (7%) when
the reaction mixture was quenched by the addition of water
after stirring for 3 h.
For the transformation of the anionic intermediate 13
into the final product 11, we propose here two possible
mechanisms as shown in Scheme 7. In the first mechanism,
the intramolecular cyclization of 13 may give stannacyclo-
propabenzene 2c, and the subsequent ring-opening reaction
of the three-membered ring in 2c results in the formation
of cyclic compound 11 along with the 1,6-migration of a
trimethylsilyl group (path A).[19] The other is the direct nu-
cleophilic attack of the anionic center of 13 toward one of
the trimethylsilyl groups followed by the ring-closure reac-
tion giving 11 (path B).
In our previous works, there was no evidence of the for-
mation of silicon or germanium analogues of the anionic
intermediate 13 under any conditions for the reactions of
dilithiosilane or dilithiogermane with o-dibromobenzene. In
fact, these anionic species were not detected by quenching
reactions using D2O.[9,10] These results suggest that these
anionic species of silicon and germanium readily undergo
intramolecular cyclization reactions giving metallacyclopro-
pabenzenes, 2a and 2b. Thus, the different results among
Scheme 6. Reaction of 1a–d with o-dibromobenzene.
Although the detailed formation mechanism for 11 is not the reactions of 1a, 1b, 1c, and 1d with o-dibromobenzene
clear at present, compound 13 might be formed as an initial are most likely interpreted in terms of much lower reactivity
intermediate by the mechanism similar to those in the reac- of 13 in the intramolecular cyclization to give 2c than that
tions of 1a and 1b; thus, the dilithiostannane 1c or dipot- of the silicon and/or germanium analogues or instability of
assiostannane 1d reacts with o-dibromobenzene to give the strained stannacyclopropene ring of 2c.
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T. Tajima, N. Takeda, T. Sasamori, N. Tokitoh
FULL PAPER
Scheme 8. Reaction of 1e with tellurium() dichloride.
Scheme 7. Possible formation mechanism for 11.
On the other hand, it is well known that dilithiosilanes
and dilithiogermanes are useful for the preparation of
double-bond compounds of heavier group 14 elements.[2]
Recently, we reported the synthesis of silanetellone and ger-
manetellone by the reactions of overcrowded dilithiometal-
lanes 1a and 1b with tellurium() dichloride, respec-
tively.[2g,20] Taking these results into account, the dilithio-
stannane should be a good precursor for the synthesis of a
tin–tellurium double-bond compound 16.[12] We reported
that tin–chalcogen double-bond compounds having Tbt
and 2,4,6-triisopropylphenyl (Tip) groups on the tin atom
easily underwent self-dimerization, giving 1,3,2,4-dichalco-
genastannetanes at room temperature.[13] In order to stabi-
lize a stannanethione and stannanesellone effectively, it was
necessary to use a combination of extremely bulky ligands
such as 2,2ЈЈ-diisopropylphenyl-m-terphenyl-2Ј-yl (Ditp)
and the Tbt group.[21] Therefore, we tried the synthesis of
stannanetellone having Tbt and Ditp groups.
Figure 2. ORTEP drawing of 18·1.5(toluene) (50% probability).
Hydrogen atoms and solvated toluene molecules are omitted for
clarity. Tbt and Ditp groups are described with gray lines for clar-
ity. Selected bond lengths [Å] and angles [°]: Sn1–Te1 2.7445(13),
Sn1–Te4 2.7526(13), Sn1–Te3 2.7536(13), Sn1–Te2 2.7574(13),
Sn2–Te3 2.7577(13), Sn2–Te4 2.7657(13), Te1–Sn3 2.7661(13), Te2–
Sn3 2.7627(13), Te4–Sn1–Te3 94.95(4), Te1–Sn1–Te2 95.03(4),
Te3–Sn2–Te4 94.56(4), Sn1–Te1–Sn3 85.36(4), Sn1–Te2–Sn3
85.18(4), Te2–Sn3–Te1 94.42(4), Sn1–Te3–Sn2 85.27(4), Sn1–Te4–
Sn2 85.13(4).
Interestingly, treatment of a THF solution of Tbt(Ditp)-
Although the formation mechanism of 18 is not clear at
SnLi2 (1e)[22] with tellurium() dichloride[23] at –78 °C af- present, the formation of 18 can be explained in terms of a
forded a unique cyclic compound 18 (8%) along with mechanism similar to the case of the formation of a spirobi-
TbtTeTeTbt (19; 11%), DitpH (20; 70%), and TbtH (73%), (dithiasiletane) in the reaction of a silylene with S8 through
(Scheme 8). Orange crystals of 18 are stable under air for the corresponding silanethione and silanethione dimer.[25]
at least several weeks. The 119Sn NMR signals of the cyclic Based on this report, the self-dimerization of stannanetel-
compound, spirobi(ditelluradistannetane) 18, were ob- lone 16, which is generated in the reaction of dilithiostan-
served at δ = –149, –384, and –387 ppm in C6D6. The 125Te nane 1e with tellurium() dichloride, afforded stannanetel-
NMR chemical shift of 18 was observed at δ = 762.9, 765.0, lone dimer 17 and the subsequent reactions of 17 result in
766.0, and 771.3 ppm in C6D6. The molecular structure of the formation of cyclic compound 18. The formation of 18
18 was finally determined by X-ray crystallographic analy- indicates that some amount of stannanetellone 16 might be
sis (Figure 2). Both ditelluradistannetane rings were found generated in the reaction of 1e with tellurium() dichloride;
to be nearly planar (the sums of interior bond angles are however, on the other hand, it suggests that stannanetel-
about 359.99° and 359.91°, respectively). The three tin lones are much less stable and much more difficult to isolate
atoms are situated in a linear alignment (angle of Sn2–Sn1– than the silicon and germanium analogues such as silanetel-
Sn3: 179.9°). All Sn–Te bond lengths [2.7445(13)– lones and germanetellones and the lighter chalcogen ana-
2.7661(13)] Å are in the range reported for 1,3,2,4-ditellura- logues (e.g., stannanethiones and stannanesellones), be-
distannetanes, [(Dis)2SnTe]2 [Dis = –CH(SiMe3)2] [2.756(1) cause of the longer Sn–Te bonds and larger energy gaps
and 2.771(1) Å][24a] and (tBu2SnTe)2 [2.754(1) and between σ- and π-bond energies than those of the lighter
2.758(1) Å].[24b]
element(s) analogues. In order to isolate a stable stannane-
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Diaryldilithiostannane and Diaryldipotassiostannane
FULL PAPER
tion (50 mL) of DipMgBr (5.78 g, 21.8 mmol), which was prepared
by the reaction of Mg (602 mg, 24.8 mmol) and DipBr (5.25 g,
21.8 mmol), was added to a THF solution (100 mL) of the mixture
of TbtSnCl3–nBrn (n = 0–3) (10.1 g) at room temperature. After the
solution was stirred under reflux conditions for 16 h, the reaction
mixture was cooled to room temperature. LiAlH4 (6.00 g,
19.5 mmol) was added to the reaction mixture at 0 °C and then the
mixture was stirred for 5 h. After quenching by an ice-cold 15%
NaOH solution (100 mL) and the subsequent filtration to remove
the insoluble inorganic salts, the organic layer was extracted. After
extraction with hexane (50 mL), the organic layers were combined,
washed with H2O, and then dried with Na2SO4. After the removal
of the solvent, the mixture was purified by column chromatography
(SiO2/hexane) to afford Tbt(Dip)SnH2 (3) as colorless crystals.
Yield: 4.0 g (33%). M.p. 155.5 °C (dec.). C39H78Si6Sn (834.26):
calcd. C 56.15, H 9.42; found C 56.06, H 9.51. FAB-MS: m/z calcd.
for C39H78Si6120Sn 834 [M+], found 834 [M+]. 1H NMR (300 MHz,
C6D6, 25 °C): δ = 0.30 (s, 9 H, SiMe3), 0.32 (s, 36 H, SiMe3), 0.35
tellone, it is necessary to introduce a much more crowded
combination of the protection groups than that in
Tbt(Ditp)Sn=Te.
Conclusions
By taking advantage of a bulky substituent, Tbt group,
we succeeded in the generation of diaryldimetallastannanes
1c, 1d, and 1e by the exhaustive reduction of overcrowded
diaryldibromostannanes 4 and 15. We found that the reac-
tions of 1c and 1d with o-dibromobenzene resulted in the
formation of an unexpected compound 11 instead of the
expected stannacyclopropabenzene 2c. The reaction of 1e
with tellurium() dichloride afforded a novel cyclic com-
pound 18. As 1c and 1d were found to have enough stability
in solution at low temperature, further investigation of their
synthetic application toward a variety of tin-containing new
chemical species is currently in progress.
3
3
(s, 9 H, SiMe3), 1.34 (d, JHH = 5.5 Hz, 6 H, CH3), 1.51 (d, JHH
= 5.5 Hz, 6 H, CH3), 1.61 (s, 1 H, p-BnH for Tbt), 2.15 (br. s, 1
H, o-BnH for Tbt), 2.45 (br. s, 1 H, o-BnH for Tbt), 2.91 (sept,
3JHH = 5.5 Hz, 2 H, BnH for Dip), 6.38 (s, 1J
= 1769.4,
117SnH
1J119SnH = 1855.2 Hz, 2 H, SnH2), 6.73 (br. s, 1 H, m-PhH for Tbt),
6.87 (br. s, 1 H, m-PhH for Tbt), 7.14–7.50 (m, 3 H, m- and p-PhH
for Dip) ppm. 13C NMR (75 MHz, C6D6, 25 °C): δ = 0.6 (q), 1.0
(q), 1.2 (q), 25.1 (q), 30.6 (d), 33.3 (d), 37.5 (d×2), 122.1 (d), 123.1
(d), 127.0 (d), 130.1 (d), 135.6 (s), 140.1 (s), 143.9 (s), 151.74 (s),
151.83 (s), 155.4 (s) ppm. 119Sn{1H} NMR (111 MHz, C6D6,
Experimental Section
General: All experiments were performed under argon unless other-
wise noted. THF was dried by standard methods and freshly dis-
tilled prior to use. 1H NMR (300 MHz), 13C NMR (75 MHz),
119Sn NMR (111 MHz), and 125Te NMR (94 MHz) spectra were
measured in CDCl3 or C6D6 with a JEOL JNM AL-300 spectrome-
ter. 1H and 13C NMR chemical shifts were recorded in ppm relative
to tetramethylsilane (δ = 0 ppm) and were referenced internally
with respect to the residual proton impurity (CHCl3: δ = 7.26 ppm,
benzene: δ = 7.15 ppm) and the 13C resonance of the solvent
(CDCl3: δ = 77.2 ppm, [D6]benzene: δ = 128.0 ppm), respectively.
119Sn NMR chemical shifts were referenced with tetramethylstan-
nane (δ = 0 ppm) as an external standard. 125Te NMR chemical
shifts were referenced with diphenylditelluride (δ = 450 ppm) as an
external standard. Fast atom bombardment (FAB) mass spectro-
metric data were obtained with a JEOL JMS-700 spectrometer.
Mass spectrometric data (EI) were obtained with a Shimadzu QP-
5000. Preparative gel permeation liquid chromatography (GPLC)
was performed with an LC-918 apparatus (Japan Analytical Indus-
try Co., Ltd.) equipped with JAIGEL 1H and 2H columns (eluent:
CHCl3 or toluene). Preparative thin-layer chromatography (PTLC)
was performed with Merck Kieselgel 60 PF254. All melting points
were determined with a Yanaco micro melting point apparatus and
are uncorrected. IR spectra were measured at room temperature
with a JASCO FT/IR-460 plus. Elemental analyses were carried
out at the Microanalytical Laboratory of the Institute for Chemical
Research, Kyoto University. 1-Bromo-2,4,6-tris[bis(trimethylsilyl)-
25 °C): δ = –345.6 ppm. IR (KBr): ν = 1863.9 [ν(Sn–H)] cm–1.
˜
Tbt(Dip)SnBr2 (4): A solution of 3 (3.70 g, 4.43 mmol) and Br2
(0.50 mL, 9.76 mmol) in Et2O (130 mL) was stirred at room tem-
perature for 2 h. The solution was washed with an aqueous solution
of NaOH and then with a saturated aqueous solution of NaCl.
The organic layer was dried with Na2SO4. After the removal of the
solvent, the residue was recrystallized from CHCl3 and EtOH to
afford 4 as colorless crystals. Yield: 2.98 g (68%). M.p. 188.4–
192.5 °C. C39H76Br2Si6Sn (992.05): calcd. C 47.22, H 7.72; found
C 47.24, H 7.82. FAB-MS: m/z calcd. for C39H7679Br2Si6120Sn 992
[M+], found 992 [M+]. 1H NMR (300 MHz, CDCl3, 25 °C): δ =
0.03 (s, 36 H, SiMe3), 0.05 (s, 18 H, SiMe3), 1.16 (s, 1 H, p-BnH
3
for Tbt), 1.33 (d, JHH = 6.6 Hz, 12 H, CH3), 2.13 (br. s, 1 H, o-
3
BnH for Tbt), 2.43 (br. s, 1 H, o-BnH for Tbt), 3.36 (sept, JHH
=
6.6 Hz, 2 H, BnH for Dip), 6.37 (br. s, 1 H, m-PhH for Tbt), 6.47
(br. s, 1 H, m-PhH for Tbt), 7.20–7.42 (m, 3 H, m- and p-PhH for
Dip) ppm. 13C NMR (75 MHz, CDCl3, 25 °C): δ = 1.2 (q), 1.8 (q),
2.0 (q), 26.4 (q), 31.1 (d), 31.8 (d), 37.4 (d×2), 123.6 (d), 125.4 (d),
128.4 (d), 131.6 (d), 133.7 (s), 137.5 (s), 143.8 (s), 146.7 (s), 151.0
(s), 154.5 (s) ppm. 119Sn NMR (111 MHz, CDCl3, 25 °C): δ =
–171.0 ppm.
Generation of Tbt(Dip)SnM2 (M = Li, K) and Preparation of
Tbt(Dip)SnMe2 (5). Method A (M = Li): Lithium naphthalenide
(2.33  solution in THF, 0.14 mL, 0.33 mmol, 5 molar amounts)
was added to a THF solution (1.0 mL) of 4 (62.4 mg, 62.9 µmol)
at –78 °C. The reaction mixture was stirred at the same temperature
for 1 h, and then an excess amount of MeI (0.1 mL, 1.6 mmol) was
added to the reaction mixture. After the removal of the solvent, the
methyl]benzene
(TbtBr),[26]
1-bromo-2,6-diisopropylbenzene
(DipBr),[27]
and
2Ј-iodo-2,2ЈЈ-diisopropyl-1,1Ј:3Ј1ЈЈ-terphenyl
(DitpI)[21] were prepared according to reported procedures.
Tbt(Dip)SnH2 (3): tBuLi (2.30  solution in pentane, 35.2 mL,
81.0 mmol) was added to a solution of TbtBr (22.5 g, 35.6 mmol)
in THF (380 mL) at –78 °C. After the reaction mixture was stirred
at the same temperature for 30 min, SnCl4 (5.0 mL, 42.7 mmol) residue was extracted with hexane several times. Insoluble inor-
and LiCl (34.4 g, 0.81 mol) were added at –78 °C. The mixture was
warmed to room temperature, and then the solvents were evapo-
rated. After removal of the insoluble inorganic salts by filtration
through Celite®, the reaction mixture was concentrated to give col-
orless crystals. Recrystallization from CH3CN/CHCl3 afforded a
mixture of TbtSn(Hal)3 (Hal = Cl and/or Br) (16.4 g). A THF solu-
ganic salts were removed by filtration through Celite®. The residue
was subjected to GPLC (CHCl3) followed by PTLC (hexane) to
afford 5 as colorless crystals. Yield: 52.7 mg (97%). Method B (M
= K): KC8 (98.0 mg, 0.72 mmol) was added to a THF solution
(1.0 mL) of 4 (68.0 mg, 68.5 µmol) at –110 °C. The reaction mix-
ture was stirred vigorously at the same temperature for 1 h, and
Eur. J. Inorg. Chem. 2005, 4291–4300
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4295

T. Tajima, N. Takeda, T. Sasamori, N. Tokitoh
FULL PAPER
2
then an excess of MeI (0.1 mL, 1.6 mmol) was added to the mix-
ture. A similar workup procedure mentioned above afforded 5 as
colorless crystals. Yield: 63.5 mg (93%). M.p. 167.9–174.3 °C.
C41H82Si6Sn (862.31): calcd. C 57.11, H 9.58; found C 56.96, H
9.59. FAB-MS: m/z calcd. for C41H82Si6120Sn 863 [M+], found 863
[M+]. 1H NMR (300 MHz, CDCl3, 25 °C): δ = –0.05 (s, 18 H,
s, 6 H, CH3), 1.79 (s, 1 H, o-BnH for Tbt), 2.09 (d, J = 17.0 Hz,
3
2 H, CH2), 2.14 (d, 4J = 17.0 Hz, 2 H, CH2), 3.02 (sept, JHH
=
3
6.6 Hz, 1 H, BnH for Dip), 3.12 (sept, JHH = 6.6 Hz, 1 H, BnH
for Dip), 6.27 (br. s, 1 H, m-PhH for Tbt), 6.41 (s, 1 H, m-PhH for
3
3
Tbt), 7.12 (d, JHH = 7.5 Hz, 2 H, m-PhH for Dip), 7.23 (t, JHH
= 7.5 Hz, 1 H, p-PhH for Dip) ppm. 13C NMR (75 MHz, CDCl3,
SiMe3), –0.01 (s, 18 H, SiMe3), 0.02 (s, 18 H, SiMe3), 0.64 (s, 2JHSn 25 °C): δ = 0.8 (q), 1.1 (q), 1.3 (q), 21.4 (q), 24.9 (q), 25.8 (q), 30.1
3
= 48.3 Hz, 6 H, SnMe), 1.23 (d, JHH = 5.5 Hz, 12 H, CH3), 1.31
(s, 1 H, p-BnH for Tbt), 1.68 (br. s, 1 H, o-BnH for Tbt), 1.84 (br.
s, 1 H, o-BnH for Tbt), 2.99 (sept, JHH = 5.5 Hz, 2 H, BnH for
Dip), 6.25 (br. s, 1 H, m-PhH for Tbt), 6.38 (br. s, 1 H, m-PhH for
Tbt), 7.18–7.40 (m, 3 H, m- and p-PhH for Dip) ppm. 13C NMR
(75 MHz, C6D6, 25 °C): δ = 0.9 (q), 1.2 (q), 1.5 (q), 3.7 (q), 26.0
(q), 30.0 (d), 30.7 (d), 30.9 (d), 36.5 (d), 122.1 (d), 123.1 (d), 127.0
(d), 128.9 (d), 131.8 (s), 137.2 (s), 143.0 (s), 143.9 (s), 151.3 (s),
155.4 (s) ppm. 119Sn NMR (111 MHz, CDCl3, 25 °C): δ =
–126.4 ppm.
(d), 31.1 (d), 31.5 (d×2), 32.6 (t), 37.9 (d), 122.0 (d), 123.1 (d),
124.6 (d), 128.9 (d), 131.7 (s), 137.7 (s), 141.2 (s), 142.9 (s), 145.7
(s), 151.2 (s), 154.7 (s) ppm. 119Sn NMR (111 MHz, CDCl3, 25 °C):
δ = –110.2 ppm.
3
Generation of Tbt(Dip)SnK2 and the Trapping Reaction of the De-
composed Compounds with H2O at Room Temperature: KC8
(129 mg, 0.95 mmol) was added to a THF solution (1.5 mL) of 4
(101 mg, 0.10 mmol) at –110 °C. The reaction mixture was stirred
vigorously at the same temperature for 1 h, and then warmed to
room temperature. After additional stirring at the same tempera-
ture for 1 h, the reaction mixture was exposed to air. After the
removal of the solvent, the mixture was extracted with hexane se-
veral times. Insoluble inorganic salts were removed by filtration
through Celite® and the filtrate was concentrated. The residue was
subjected to GPLC (CHCl3) followed by PTLC (hexane) to give
TbtH (12.1 mg, 20%), 10 (39.7 mg, 72%), and DipH (14.1 mg,
80%).[17]
Generation of Tbt(Dip)SnLi2 and the Trapping Reaction with DCl:
Lithium naphthalenide (1.26  solution in THF, 0.22 mL,
0.28 mmol, 5 molar amounts) was added to a THF solution
(1.0 mL) of 4 (58.6 mg, 59.1 µmol) at –78 °C. The reaction mixture
was stirred at the same temperature for 1 h. After stirring for
30 min, DCl (1.0  solution in Et2O, 75 µL) was added to the reac-
tion mixture. After the removal of the solvent, the mixture was
extracted with hexane several times. The extracts were combined,
filtered through Celite®, and the solvents evaporated. The residue
was subjected to GPLC (toluene) to give Tbt(Dip)SnD2 (3a) as
colorless crystals. Yield: 47.5 mg [96% (deuterium content: 93%)].
M.p. 154.8 °C (dec.). High-resolution FAB-MS: m/z calcd. for
Stannacyclobutabenzene (11). Method A: Lithium naphthalenide
(1.56  solution in THF, 0.67 mL, 5 molar amounts) was added to
a THF solution (5.0 mL) of 4 (205 mg, 0.21 mmol) at –78 °C. After
stirring at the same temperature for 1 h, o-dibromobenzene (25 µL,
0.21 mmol) was added to the reaction mixture. The solution was
slowly warmed to room temperature over 10 h. After the removal
of the solvent, hexane was added to the residue. Insoluble inorganic
salts were removed by filtration through Celite® and the filtrate
was concentrated. The residue was subjected to GPLC (CHCl3)
followed by PTLC (hexane) to give 11 as colorless crystals. Yield:
30.1 mg (16%). Method B: KC8 (150 mg, 1.11 mmol) was added to
C39H76D2Si6120Sn 836.3865 [M+], found 836.3894 [M+]. H NMR
(300 MHz, C6D6, 25 °C): δ = 0.30 (s, 9 H, SiMe3), 0.32 (s, 36 H,
1
3
SiMe3), 0.35 (s, 9 H, SiMe3), 1.34 (d, JHH = 5.5 Hz, 6 H, CH3),
3
1.51 (d, JHH = 5.5 Hz, 6 H, CH3), 1.61 (s, 1 H, p-BnH for Tbt),
2.15 (br. s, 1 H, o-BnH for Tbt), 2.45 (br. s, 1 H, o-BnH for Tbt),
3
2.91 (sept, JHH = 5.5 Hz, 2 H, BnH for Dip), 6.73 (br. s, 1 H, m-
PhH for Tbt), 6.87 (br. s, 1 H, m-PhH for Tbt), 7.14–7.50 (m, 3 H,
m- and p-PhH for Dip) ppm. 13C NMR (75 MHz, C6D6, 25 °C): δ
= 0.6 (q), 1.0 (q), 1.2 (q), 25.1 (q), 30.6 (d), 33.3 (d), 37.5 (d×2),
122.1 (d), 123.1 (d), 127.0 (d), 130.1 (d), 135.6 (s), 140.1 (s), 143.9
(s), 151.74 (s), 151.83 (s), 155.4 (s) ppm. 119Sn NMR (111 MHz,
C6D6, 25 °C): δ = –346.8 (quint, 1JSnD = 280.7 Hz) ppm. IR (KBr):
a
THF solution (3.0 mL) of Tbt(Dip)SnBr2 (4) (170 mg,
0.17 mmol) at –78 °C. After stirring at the same temperature for
1 h, o-dibromobenzene (25 µL, 0.21 mmol) was added to the reac-
tion mixture. The solution was slowly warmed to room temperature
over 10 h, and 11 was separated and purified by a procedure similar
to that described above. Yield: 40.1 mg (26%). M.p. 99.4 °C (dec.).
C45H80Si6Sn (908.34): calcd. C 59.50, H 8.88; found C 59.53, H
8.63. FAB-MS: m/z calcd. for C45H80Si6120Sn 908 [M+], found 908
[M+]. 1H NMR (300 MHz, CDCl3, 25 °C): δ = –0.26 (s, 9 H,
SiMe3), –0.16 (s, 9 H, SiMe3), 0.02 (s, 9 H, SiMe3), 0.04 (s, 9 H,
SiMe3), 0.15 (s, 9 H, SiMe3), 0.17 (s, 9 H, SiMe3), 0.86 (br. s, 6 H,
Me), 1.24 (br. s, 6 H, Me), 1.34 (s, 1 H, BnH), 1.57 (s, 1 H, BnH),
ν = 1317.1 [ν(Sn–D)] cm–1.
˜
Generation of Tbt(Dip)SnLi2 (1c) and the Trapping Reaction of the
Decomposed Compounds with 2,3-Dimethyl-1,3-butadiene and MeI:
Lithium naphthalenide (1.03  solution in THF, 0.25 mL,
0.26 mmol, 5 molar amounts) was added to a THF solution
(1.0 mL) of 4 (50.2 mg, 50.0 µmol) at –78 °C. The reaction mixture
was stirred at the same temperature for 1 h. After additional stir-
ring at room temperature for 30 min, 2,3-dimethyl-1,3-butadiene
(0.1 mL, 82.0 µmol) was added. After stirring for 30 min, an excess
of MeI (0.1 mL, 1.6 mmol) was added to the reaction mixture. Af-
ter the removal of the solvent, hexane was added to the residue.
Insoluble inorganic salts were removed by filtration through Ce-
lite® and the filtrate was concentrated. The residue was subjected
to GPLC (CHCl3) followed by PTLC (hexane) to give TbtH
(14.7 mg, 53%) and 9 (20.4 mg, 45%). M.p. 164.2–166.4 °C. FAB-
MS: m/z calcd. for C45H87Si6120Sn 915 [M + H]+, found 915 [M +
H]+. High-resolution FAB-MS: m/z calcd. for C45H87Si6120Sn
915.4445 [M + H]+, found 915.4456 [M + H]+. 1H NMR
(300 MHz, CDCl3, 25 °C): δ = –0.05 (br. s, 18 H, SiMe3), –0.24 (br.
2
2.94 (s, JHSn = 64 Hz, 1 H, BnH), 3.29 (br. s, 2 H, BnH for Dip),
6.39 (br. s, 1 H, m-PhH for Tbt), 6.45 (s, 1 H, m-PhH for Tbt),
3
7.07 (d, JHH = 7.2 Hz, 2 H, m-PhH for Dip), 7.20–7.27 (m, 2 H,
3
3
PhH), 7.30 (t, JHH = 7.2 Hz, 1 H, p-PhH for Dip), 7.60 (dd, JHH
4
3
4
= 7.2, JHH = 2.1 Hz, 1 H, PhH), 7.93 (dd, JHH = 7.2, JHH
=
2.1 Hz, 1 H, PhH) ppm. 13C NMR (75 MHz, CDCl3, 50 °C): δ =
0.2 (q), 0.39 (q), 0.44 (q), 0.5 (q), 0.6(q), 1.1 (q), 24.9 (br. q), 30.2
(d), 30.4 (d), 37.1 (d), 39.7 (d), 121.8 (br. d), 123.2 (d), 123.4 (d),
127.5 (d), 128.0 (d), 129.5 (d), 135.8 (d), 138.0 (d), 143.9 (s), 145.0
(s), 145.1 (s), 147.5 (s), 147.7 (s), 154.6 (s), 155.0 (s), 155.8 (s) ppm.
119Sn{1H} NMR (111 MHz, CDCl3, 25 °C): δ = –83.4 ppm.
Tbt(Dip)Sn(Ph)Br (14): Lithium naphthalenide (1.30  solution in
THF, 1.87 mL, 5 molar amounts) was added to a THF solution
(10 mL) of 4 (479 mg, 0.48 mmol) at –78 °C. After stirring at the
same temperature for 1 h, o-dibromobenzene (65 µL, 0.54 mmol)
3
s, 18 H, SiMe3), 0.03 (s, 18 H, SiMe3), 1.19 (d, JHH = 6.6 Hz, 9
H, CH3 for Dip), 1.19 (br. s, 1 H, p-BnH for Tbt), 1.28 (d, JHH
6.6 Hz, 3 H, CH3 for Dip), 1.68 (s, 1 H, o-BnH for Tbt), 1.74 (br.
3
=
4296
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 4291–4300

Diaryldilithiostannane and Diaryldipotassiostannane
FULL PAPER
1
was added to the reaction mixture. The solution was stirred for 3 h,
and then the mixture was separated by the procedure similar to
that described above to afford 11 (29.0 mg, 7%) and 14 (29.6 mg,
found 1144 [M+]. H NMR (300 MHz, C6D6, 25 °C): δ = 0.19 (br.
3
s, 36 H, SiMe3), 0.21 (br. s, 18 H, SiMe3), 1.03 (d, JHH = 6.3 Hz,
3
6 H, Me), 1.39 (d, JHH = 6.3 Hz, 6 H, Me), 1.51 (br. s, 1 H, p-
6%). M.p. 155.8 °C (dec.). FAB-MS: m/z calcd. for BnH for Tbt), 1.80 (br. s, 1 H, o-BnH for Tbt), 2.82 (br. s, 1 H, o-
C45H8179BrSi6120Sn 988 [M+], found 988 [M+]. High-resolution
BnH for Tbt), 2.96 (sept, 3JHH = 6.3 Hz, 2 H, BnH for Ditp), 6.37–
FAB-MS: m/z calcd. for C45H8179BrSi6120Sn 988.3159 [M+], found
6.75 (m, 2 H, m-PhH for Tbt), 7.01–7.35 (m, 9 H, ArH for Ditp),
1
3
988.3193 [M+]. H NMR (300 MHz, CDCl3, 25 °C): δ = –0.16 (s, 7.45 (d, JHH = 7.2 Hz, 2 H, ArH for Ditp) ppm. 13C NMR
27 H, SiMe3), –0.13 (s, 9 H, SiMe3), –0.07 (s, 9 H, SiMe3), –0.06
(75 MHz, C6D6, 25 °C): δ = 0.6 (q), 1.9 (q), 2.4 (q), 2.6 (q), 23.2
(q), 25.2 (q), 30.0 (d), 31.1 (d), 32.8 (d), 33.1 (d), 123.4 (d), 123.9
3
3
(s, 9 H, SiMe3), 0.83 (d, JHH = 6.3 Hz, 6 H, Me), 1.20 (d, JHH
=
6.3 Hz, 6 H, Me), 1.23 (s, 1 H, p-BnH for Tbt), 1.97 (br. s, 1 H, o- (d), 126.3 (d), 126.9 (d), 128.8 (d), 129.4 (d), 129.7 (d), 135.3 (d),
3
BnH for Tbt), 2.02 (br. s, 1 H, o-BnH for Tbt), 3.18 (sept, JHH
=
141.1 (s×2), 142.9 (s), 146.1 (s), 146.4 (s) 147.7 (s), 148.8 (s), 153.5
6.3 Hz, 2 H, BnH for Dip), 6.24 (br. s, 1 H, m-PhH for Tbt), 6.36
(br. s, 1 H, m-PhH for Tbt), 7.05–7.13 (m, 2 H, PhH), 7.20–7.28
(m, 4 H, PhH), 7.59–7.82 (m, 2 H, PhH) ppm. 13C NMR (75 MHz,
CDCl3, 25 °C): δ = 0.8 (q), 1.0 (q), 1.7 (q), 1.9 (q), 24.3 (q), 27.2
(q), 30.5 (d), 31.1 (d), 31.5 (d), 36.8 (d), 122.9 (d), 124.6 (d), 127.2
(d), 128.3 (d), 129.2 (d), 130.3 (d), 136.5 (d), 138.4 (s), 140.2 (s),
144.9 (s), 147.0 (s), 151.2 (s), 154.6 (s), 155.2 (s) ppm. 119Sn{1H}
NMR (111 MHz, CDCl3, 25 °C): δ = –102.2 ppm.
(s) ppm. 119Sn{1H} NMR (111 MHz, CDCl3, 25 °C):
–192.5 ppm.
δ =
Generation of Tbt(Ditp)SnLi2 and Preparation of Tbt(Ditp)SnMe2:
Lithium naphthalenide (1.30  solution in THF, 0.15 mL,
0.20 mmol, 5 molar amounts) was added to a THF solution
(1.0 mL) of 15 (45.6 mg, 39.8 µmol) at –78 °C. The reaction mix-
ture was stirred at the same temperature for 1 h, and then MeI
(0.1 mL, 1.6 mmol) was added to the reaction mixture. After the
removal of the solvent, hexane was added to the residue. Insoluble
inorganic salts were removed by filtration through Celite®. The fil-
trate was concentrated and subjected to GPLC (CHCl3) followed
by PTLC (hexane) to afford Tbt(Ditp)SnMe2 as colorless crystals.
Yield: 38.1 mg (93%). M.p. 265.3–265.7 °C. C53H90Si6Sn (1014.50):
calcd. C 62.75, H 8.94; found C 62.67, H 9.05. High-resolution
FAB-MS: m/z calcd. for C53H90Si6120Sn 1014.4680 [M+], found
Synthesis of Tbt(Ditp)SnH2:
A THF solution (20 mL) of
TbtSn(Hal)3 (2.31 g) was added to a THF solution of DitpLi, pre-
pared from DitpI (1.49 g, 3.37 mmol) and tBuLi (2.32  in pentane,
3.2 mL, 7.41 mmol) at –78 °C in THF (20 mL), at –78 °C, and then
the mixture was stirred at room temperature for 2 h. After the re-
moval of the solvent, hexane was added to the residue. Insoluble
inorganic salts were removed by filtration through Celite®. The fil-
trate was concentrated and subjected to GPLC (CHCl3) to afford a
mixture containing Tbt(Ditp)Sn(Hal)2 (1.48 g) as colorless crystals.
LiAlH4 (734 mg, 19.3 mmol) was added to a THF solution (50 mL)
of the mixture containing Tbt(Ditp)Sn(Hal)2 (1.28 g) at 0 °C. The
mixture was stirred at room temperature for 3 h. After quenching
by an ice-cold 15% NaOH solution (30 mL) and subsequent fil-
tration to remove the insoluble inorganic salts, the organic layer
was extracted. After extraction with hexane (50 mL), the organic
layers were combined, and washed with H2O, and then dried with
Na2SO4. After removal of the solvents, the mixture was purified by
column chromatography (SiO2/benzene) to afford Tbt(Ditp)SnH2
as colorless crystals. Yield 962 mg (29%). M.p. 155.5 °C (dec.).
FAB-MS: m/z calcd. for C51H87Si6118Sn 985 [M + H]+, found 985
1
1014.4697 [M+]. H NMR (300 MHz, CDCl3, 25 °C): δ = –0.45 (s,
2JHSn = 51.0 Hz, 6 H, SnMe), –0.04 (br. s, 36 H, SiMe3), –0.09 (s,
3
3
18 H, SiMe3), 1.04 (d, JHH = 6.6 Hz, 6 H, Me), 1.15 (d, JHH
=
6.6 Hz, 6 H, Me), 1.27 (s, 1 H, p-BnH for Tbt), 1.32 (br. s, 2 H, o-
BnH for Tbt), 2.71 (sept, 3JHH = 6.6 Hz, 2 H, BnH for Ditp), 6.25
(br. s, 1 H, m-PhH for Tbt), 6.40 (br. s, 1 H, m-PhH for Tbt), 6.98
3
3
(t, JHH = 7.2 Hz, 1 H, PhH for Ditp), 7.13 (d, JHH = 7.2 Hz, 2
H, PhH for Ditp), 7.21–7.39 (m, 8 H, PhH for Ditp) ppm. 13C
NMR (75 MHz, CDCl3, 25 °C): δ = –0.4 (q, 1J
= 339.6,
117SnC
1J
= 346.0 Hz), 1.0 (q), 1.9 (q), 2.2 (q), 22.8 (q), 24.9 (q), 29.2
119SnC
(d×2), 29.8 (d), 31.1 (d), 121.9 (d), 122.5 (d), 125.4 (d), 125.8 (d),
126.8 (d), 127.7 (d), 128.9 (d), 130.0 (d, 3JSnC = 37.7 Hz), 140.1 (s),
142.3 (s), 143.1 (s), 143.7 (s), 147.3 (s), 148.2 (s), 150.3 (s), 150.7 (s)
[M + H]+. 1H NMR (300 MHz, C6D6, 25 °C): δ = 0.09 (s, 36 H, ppm. 119Sn{1H} NMR (111 MHz, CDCl3, 25 °C): δ = –114.9 ppm.
SiMe3), 0.20 (s, 18 H, SiMe3), 0.95 (d, JHH = 5.1 Hz, 6 H, Me),
1.40 (d, JHH = 5.1 Hz, 6 H, Me), 1.43 (s, 1 H, p-BnH for Tbt),
3
Reaction of Tbt(Ditp)SnLi2 (1e) with Tellurium(II) Dichloride: Lith-
ium naphthalenide (1.24  solution in THF, 0.38 mL, 0.47 mmol,
3
1.71 (br. s, 1 H, o-BnH for Tbt), 1.85 (br. s, 1 H, o-BnH for Tbt),
5 molar amounts) was added to a THF solution (1.0 mL) of 15
3
1
117SnH
3.01 (sept, JHH = 5.1 Hz, 2 H, BnH for Ditp), 5.66 (s, J
1768.6, J
=
(108 mg, 94.0 µmol) at –78 °C. After stirring at the same tempera-
ture for 1 h, tellurium() dichloride (20.2 mg, 101 µmol) was added
to the reaction mixture. The solution was slowly warmed to room
temperature over 10 h. After the removal of the solvent, hexane
was added to the residue. Insoluble inorganic salts were removed
by filtration through Celite® and the solvents evaporated. The resi-
due was subjected to GPLC (toluene) to give TbtH (37.8 mg, 73%),
18 (19.6 mg, 8%), 19 (20.2 mg, 11%), and 20 (20.6 mg, 70%).
1
119SnH
= 1851.7 Hz, 2 H, SnH), 6.41 (br. s, 1 H, m-PhH
for Tbt), 6.53 (br. s, 1 H, m-PhH for Tbt), 7.09–7.26 (m, 9 H, ArH
for Ditp), 7.52 (d, JHH = 6.6 Hz, 2 H, ArH for Ditp) ppm. 13C
3
NMR (75 MHz, C6D6, 25 °C): δ = 1.1 (q), 1.7 (q), 22.4 (q), 24.8
(q), 30.2 (d), 30.4 (d), 32.4 (d×2), 122.5 (d), 125.4 (d), 125.7 (d),
126.2 (d), 128.9 (d), 129.4 (d), 129.7 (d), 135.3 (d), 139.0 (s), 141.2
(s), 143.2 (s), 143.7 (s) 147.2 (s), 149.8 (s), 151.2 (s) 151.3 (s) ppm.
119Sn{1H} NMR (111 MHz, C6D6, 25 °C): δ = –342.9 ppm. IR
18:
C102H168Si12Sn3Te4·1.5(toluene) (2736.22): calcd.
6.63; found 49.03,
C51H84Si6120Sn2130Te3 1488 [{M – Tbt(Ditp)SnTe}+], found 1488
Orange
crystals.
M.p.
129.7
°C
(dec.).
(KBr): ν = 1841.7 [ν(Sn–H)] cm–1.
˜
C
49.38,
H
Synthesis of Tbt(Ditp)SnBr2 (15): A solution of Tbt(Ditp)SnH2
(734 mg, 0.74 mmol) and Br2 (0.21 mL, 0.84 mmol) in Et2O
(40 mL) was stirred at room temperature for 30 min. The solution
was washed with a saturated aqueous solution of Na2SO3 and then
with a saturated aqueous solution of NaCl. The organic layer was
dried with Na2SO4. After the removal of the solvent, the residue
was recrystallized from CHCl3 and EtOH to afford 15 as colorless
C
H 6.85. FAB-MS: m/z calcd. for
[{M
– –
Tbt(Ditp)SnTe}+], C51H84Si6120Sn130Te 1115 [{M
Tbt(Ditp)Sn2Te3}+], found 1115 [{M – Tbt(Ditp)Sn2Te3}+]. 1H
NMR (300 MHz, C6D6, 70 °C): δ = 0.17 (br. s, 36 H, SiMe3), 0.24
3
(s, 36 H, SiMe3), 0.26 (s, 36 H, SiMe3), 1.17 (d, JHH = 6.9 Hz, 6
H, Me), 1.25 (d, JHH = 6.9 Hz, 6 H, Me), 1.46 (d, JHH = 6.9 Hz,
3
3
3
crystals.
Yield:
621 mg
(73%).
M.p.
278.5–279.6 °C.
6 H, Me), 1.55 (s, 2 H, p-BnH for Tbt), 1.58 (d, JHH = 6.9 Hz, 6
C51H84Br2Si6Sn (1144.24): calcd. C 53.53, H 7.40; found C 53.52,
H, Me), 2.93 (sept, 3JHH = 6.9 Hz, 2 H, BnH for Ditp), 2.98 (sept,
3JHH = 6.9 Hz, 2 H, BnH for Ditp), 3.64 (br. s, 2 H, o-BnH for
H 7.46. FAB-MS: m/z calcd. for C51H8479Br2Si6120Sn 1144 [M+],
Eur. J. Inorg. Chem. 2005, 4291–4300
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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T. Tajima, N. Takeda, T. Sasamori, N. Tokitoh
FULL PAPER
Tbt), 4.31 (br. s, 2 H, o-BnH for Tbt), 6.67 (br. s, 4 H, m-ArH for
7.20–7.29 (m, 8 H, ArH), 7.38 (s, 1 H, ArH) ppm. 13C NMR
(75 MHz, C6D6, 25 °C): δ = 24.3 (d), 29.8 (q), 125.7 (d), 125.8 (d),
128.1 (d), 128.7 (d), 129.6 (d), 130.3 (d), 130.8 (d), 141.4 (s), 142.4
(s), 146.5 (s) ppm.
3
Tbt), 6.88–7.11 (m, 16 H, PhH for Ditp), 7.24 (t, JHH = 7.8 Hz, 2
3
H, PhH for Ditp), 7.35 (d, JHH = 7.8 Hz, 2 H, PhH for Ditp),
3
7.43 (d, JHH = 7.8 Hz, 2 H, PhH for Ditp) ppm. 13C NMR
(75 MHz, C6D6, 70 °C): δ = 1.05 (q), 1.09 (q), 3.3 (q), 24.5 (q), 24.9
(q), 25.6 (q), 26.0 (q), 29.8 (d), 30.2 (d×2), 30.9 (d), 31.1 (d), 125.9
(d), 126.2 (d), 126.8 (d), 127.2 (d), 127.6 (d), 128.4 (d), 128.6 (d),
128.8 (d), 128.9 (d), 129.0 (d), 131.2 (d), 131.9 (d×2), 133.7 (s),
140.0 (s), 141.1 (s), 141.3 (s), 144.3 (s), 147.3 (s), 148.5 (s), 149.6
(s), 150.0 (s), 150.7 (s), 151.0 (s) ppm. 119Sn{1H} NMR (54 MHz,
C6D6, 25 °C): δ = –384.1, –386.8, –149.0 ppm. 125Te{1H} NMR
(94 MHz, C6D6, 25 °C): δ = 762.9, 765.0, 766.0, 771.3 ppm. The
coupling constant between 119Sn and 125Te could not be determined
because of low solubility of 18. 19: Green crystals. M.p. 253.2 °C
(dec.). High-resolution FAB-MS: m/z calcd. for C54H118Si12128Te2
NMR Measurement of Tbt(Dip)SnLi2 (1c): Lithium naphthalenide
(1.33  THF solution, 0.38 mL, 0.51 mmol) was added to a THF
solution (0.5 mL) of 4 (99.2 mg, 0.1 mmol) at –78 °C in a 5-mm
NMR glass tube. After it was sealed and the reaction mixture kept
at –78 °C for 30 min, the 119Sn NMR of this solution was measured
at –80 °C.
X-ray Crystallography: Single crystals of 11 and 18·1.5(toluene)
were grown by the slow concentration of their saturated solutions
in acetone and toluene, respectively, at room temperature. The sam-
ple preparation consisted of coating the crystal with hydrocarbon
1358.4554 [M+], found 1358.4556 [M+]. 1H NMR (300 MHz, oil, mounting it on a glass fiber, and placing it under a cold stream
CDCl3, 60 °C): δ = 0.08 (br. s, 36 H, SiMe3), 0.14 (br. s, 72 H,
SiMe3), 3.64 (s, 2 H, p-BnH for Tbt), 2.88 (br. s, 4 H, o-BnH for
Tbt), 6.51 (br. s, 4 H, m-PhH for Tbt) ppm. 13C NMR (75 MHz,
of N2 on the diffractometer. The intensity data of 11 and
18·1.5(toluene) were collected with a Rigaku/MSC Mercury CCD
diffractometer with graphite-monochromated Mo-Kα radiation (λ
CDCl3, 60 °C): δ = 0.8 (q×2), 1.1 (q), 30.6 (d×2), 38.1 (d), 120.7 = 0.71071 Å) to 2θmax = 50° at 103 K (Table 1). All structures were
(d), 125.5 (d), 144.4 (s), 147.5 (s), 149.8 (s), 153.3 (s) ppm.
solved by Patterson methods (DIRDIF)[28] and refined by full-ma-
trix least-squares procedures on F2 for all reflections (SHELXL-
97).[29] All hydrogen atoms except for 0.5(toluene) of
18·1.5(toluene) were placed using AFIX instructions; hydrogen
atoms of 0.5(toluene) were not placed. All the other atoms were
refined anisotropically. In the case of 18·1.5(toluene), the over-
125Te{1H} NMR (94 MHz, CDCl3, 60 °C): δ = 225.4 ppm. 20: Col-
orless liquid. EI-MS: m/z calcd. for C24H26 314 [M+], found 314
2
[M+]. 1H NMR (300 MHz, C6D6, 25 °C): δ = 1.09 (d, JHH
=
2
6.9 Hz, 12 H, Me), 3.26 (sept, JHH = 6.9 Hz, 2 H, BnH), 7.08 (t,
3JHH = 7.5 Hz, 1 H, ArH), 7.19 (d, JHH = 7.5 Hz, 2 H, ArH),
3
Table 1. Crystallographic data for 11 and 18·1.5(toluene).
11
18·1.5(toluene)
Empirical formula
Formula mass
C45H80Si6Sn
908.32
C112.50H176Si12Sn3Te4
2732.08
Crystal color
Crystal dimensions [mm]
Crystal system
Space group
colorless
orange
0.20×0.10×0.10
triclinic
0.20×0.10×0.02
triclinic
¯
¯
P1(#2)
P1(#2)
Unit cell dimensions
a [Å]
b [Å]
c [Å]
α [°]
β [°]
γ [°]
12.395(6)
13.847(8)
15.867(9)
105.633(11)
90.095(9)
91.121(8)
2622(2)
2
13.767(4)
21.023(6)
22.299(7)
95.993(7)
90.455(4)
94.119(7)
6401(3)
2
V [Å3]
Z
Dcalcd. [g·cm–3]
)
1.151
0.651
1.417
1.628
µ [mm–1]
F(000)
Radiation
Temperature [K]
θ range [°]
h,k,l range
968
2754
Mo-Kα (λ = 0.71070 Å)
103(2)
4.82–25.00
–14 Յ h Յ 14
–16 Յ k Յ 16
–18 Յ l Յ 18
16732
Mo-Kα (λ = 0.71070 Å)
103(2)
2.36–25.00
–12 Յ h Յ 16
–24 Յ k Յ 24
–26 Յ l Յ 26
41931
No. of reflections measured
No. of unique reflections
Completeness to θ
8940 (Rint = 0.0864)
96.9%
22042 (Rint = 0.0689)
97.7%
Max./min. transmission
Refinement method
No. of data/restraints/parameter
Goodness-of-fit
0.9377/0.8808
full-matrix least squares on F2
8940/0/469
1.034
0.9682/0.7367
full-matrix least squares on F2
22042/73/1210
1.025
Final R indices [I Ͼ 2σ(I)]
R1 = 0.058
wR2 = 0.108
R1 = 0.090
wR2 = 0.117
0.696/–0.596
R1 = 0.075
wR2 = 0.170
R1 = 0.121
wR2 = 0.207
1.967/–0.822
R indices (all data)
Largest diff. peak/hole [e·Å–3]
4298
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
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Eur. J. Inorg. Chem. 2005, 4291–4300

Diaryldilithiostannane and Diaryldipotassiostannane
FULL PAPER
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lapped and disordered toluene molecules were restrained to be
identical to each other using DFIX, SADI, SAME, and SIMU
instructions. The ipso-carbon atom of the Ditp group was re-
strained using ISOR instruction. The residual electron densities of
18·1.5(toluene) that are larger than 1.0 can be assigned to the heavy
elements (Si, Sn, and Te atoms) of a minor disordered molecule
(about 2%). However, the peaks for the carbon atoms of the disor-
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-276174 [18·1.5(toluene)] contain the supplementary crystallo-
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charge from The Cambridge Crystallographic Data Center via
www.ccdc.cam.ac.uk/data_request/cif.
[8]
[9]
Acknowledgments
[10]
[11]
[12]
This work was partially supported by Grants-in-Aid for the COE
Research on Elements Science (No.12CE2005), Scientific Research
(Nos. 14078213, 14204064, and 16000754), and the 21st Century
COE on Kyoto University Alliance for Chemistry (Novel Organic
Materials Creation & Transformation Project), and Nanotechnol-
ogy Support Project from the Ministry of Education, Culture,
Sports, Science, and Technology of Japan. T. T. thanks Research
Fellowships of the Japan Society for the Promotion of Science for
Young Scientists.
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It is well known that 119Sn NMR chemical shifts of halostan-
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–162.0 ppm: 0.11  THF solution at –80 °C). Dibromostan-
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[15]
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[18]
This reaction proceeded cleanly, and the H NMR spectrum of
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1
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Eur. J. Inorg. Chem. 2005, 4291–4300
www.eurjic.org
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4299

T. Tajima, N. Takeda, T. Sasamori, N. Tokitoh
FULL PAPER
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Received: April 28, 2005
Published Online: September 23, 2005
4300
© 2005 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
www.eurjic.org
Eur. J. Inorg. Chem. 2005, 4291–4300