The first kinetically stabilized stannaneselone and diselenastannirane: Synthesis by deselenation of a tetraselenastannolane and structures

Full text of DOI:10.1021/ja972221j

11124
J. Am. Chem. Soc. 1997, 119, 11124-11125
Scheme 1
The First Kinetically Stabilized Stannaneselone and
Diselenastannirane: Synthesis by Deselenation of a
Tetraselenastannolane and Structures
Masaichi Saito,† Norihiro Tokitoh, and Renji Okazaki*
Department of Chemistry, Graduate School of Science
The UniVersity of Tokyo, 7-3-1, Hongo, Bunkyo-ku
Tokyo 113 Japan
ReceiVed July 7, 1997
Recently, significant progress has been made in the chemistry
of low-coordinated and strained compounds of heavier main
group elements, especially those involving group 14 elements.1
Previous studies on such species, however, have centered on
silicon and germanium compounds, and the chemistry of such
compounds containing tin has been much less explored.
As for low-coordinated tin compounds, some stable double-
bond species with group 14 (SndSn,2 SndC,3 and SndCdN4)
and group 15 elements (SndN5 and SndP6) have been
synthesized, but tin-chalcogen double-bond compounds so far
reported are restricted to those thermodynamically stabilized
by intramolecular coordination,7 which are highly perturbed by
electron donation from neighboring nitrogen atoms to an
electron-deficient tin center as evidenced by their high-field
chemical shifts in 119Sn NMR (vide infra). We previously
reported the synthesis of heavier element analogues of a ketone
with SidS8 and GedX (X ) S, Se, Te)9 kinetically stabilized
by a very efficient steric protection group, 2,4,6-tris[bis-
(trimethylsilyl)methyl]phenyl (Tbt) group, developed by us.
Although we also described the synthetic approach to tin-
chalcogen double-bond compounds, Tbt(Tip)SndX (Tip )
2,4,6-triisopropylphenyl; X ) S, Se), by dechalcogenation of
1,2,3,4,5-tetrachalcogenastannolanes10 and chalcogenation of the
corresponding stannylene,11 they were found to be stable only
in solution and dimerize in the solid state. With regard to three-
membered ring compounds of heavier group 14 elements, a
relatively large number of examples have been described1
including those containing one chalcogen atom,12 but there is
no precedent which contains two chalcogen atoms in the ring.13
We report here that the deselenation of a tetraselenastannolane
by a phosphine reagent affords a stannaneselone without
intramolecular coordination or a diselenastannirane, depending
on the equivalence of the phosphine reagent used. Each of them
represents the first isolation of such a species.
Tetraselenastannolanes Tbt(Ar)SnSe4 (1) [1a, Ar ) 2,4,6-
tricyclohexylphenyl (Tcp), 22%; 1b, Ar ) 2,4,6-tris(1-ethyl-
propyl)phenyl (Tpp), 22%; 1c, Ar ) 2,2′′-diisopropyl-m-
terphenyl-2′-yl (Ditp), 38%], precursors for the synthesis of tin-
selenium double-bond compounds,15 were easily obtained by
the reactions of the corresponding stannylenes Tbt(Ar)Sn: with
excess of elemental selenium. Our previous observation that
Tbt(Tip)SndSe readily dimerized at ambient temperature so that
its 119Sn NMR was unable to be measured11 led us to use a
bulkier Tcp or Tpp group instead of Tip group. Treatment of
Tbt(Tcp)SnSe4 1a with 3 equiv of triphenylphosphine in toluene
gave a deep red solution, whose 119Sn signal showed a signal
at 556 ppm assignable to stannaneselone 2a. This low-field
chemical shift is characteristic of low-coordinated tin, e.g., R2-
SndSnR2 (725,2a 427.52b ppm), R2SndCR′2 (835,3a 2883b ppm),
and R2SndPR′ (658.3,6a 499.56b ppm), indicating that stan-
naneselone 2a displays an intrinsic nature of tin-selenium
double-bond compounds, in sharp contrast to the Parkin’s
terminal selenido complex whose 119Sn NMR appears at a much
higher field (-444 ppm).7a Similarly, the reaction of Tbt(Tpp)-
SnSe4 1b with 3 equiv of triphenylphosphine also gave
stannaneselone 2b (δSn: 547 ppm). Although stannaneselones
2a and 2b were stable in solution for a short time at room
temperature, the deep red color of the solution gradually
disappeared over a few hours.
† Present address: Department of Chemistry, Faculty of Science, Saitama
University, Japan.
(1) For reviews, see: (a) West, R. Pure Appl. Chem. 1984, 56, 163. (b)
Satge´, J. Pure Appl. Chem. 1984, 56, 137. (c) Raabe, G.; Michl, J. Chem.
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Satge´, J. J. Organomet. Chem. 1990, 400, 121. (g) Neumann, W. P. Chem.
ReV. 1991, 91, 311. (h) Tsumuraya, T.; Batcheller, S. A.; Masamune, S.
Angew. Chem., Int. Ed. Engl. 1991, 30, 902. (i) Brook, A. G.; Brook, M.
A. AdV. Organomet. Chem. 1996, 39, 71. (j) Okazaki, R.; West, R. AdV.
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(2) (a) Goldberg, D. E.; Harris, D. H.; Lappert, M. F.; Thomas, K. M. J.
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Chem., Int. Ed. Engl. 1987, 26, 546. (b) Anselme, G.; Ranaivonjatovo, H.;
Escudie´, J.; Couret, C.; Satge´, J. Organometallics 1992, 11, 2748.
(4) Gru¨tzmacher, H.; Freitag, S.; Herbst-Irmar, R.; Sheldrick, G. S.
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(5) Ossig, G.; Meller, A.; Freitag, S.; Herbst-Irmer, R. J. Chem. Soc.,
Chem. Commun. 1993, 497.
The unsuccessful attempts at the isolation of a stable
stannaneselone by using the combination of Tbt-Tcp and Tbt-
Tpp groups prompted us to develop a ligand even bulkier than
Tcp and Tpp. We have introduced a new efficient steric
(6) (a) Couret, C.; Escudie´, J.; Satge´, J.; Raharinirina, A.; Andriamizaka,
J. D. J. Am. Chem. Soc. 1985, 107, 8280. (b) Ranaivonjatovo, H.; Escudie´,
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(b) Leung, W.-P.; Kwok, W.-H.; Law, L. T. C.; Zhou, Z.-Y.; Mak, T. C.
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W.; Pohl, S.; Marsmann, H. Angew. Chem., Int. Ed. Engl. 1991, 30, 962.
(13) The isolation of stable dithiirane and its oxide has recently been
reported. (a) Ishii, A.; Akazawa, T.; Ding, M.-X.; Honjo, T.; Nakayama,
J.; Hoshino, M.; Shiro, M. J. Am. Chem. Soc. 1993, 115, 4914. (b) Ishii,
A.; Akazawa, T.; Maruta, T.; Nakayama, J.; Hoshino, M.; Shiro, M. Angew.
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(8) Suzuki, H.; Tokitoh, N.; Nagase, S.; Okazaki, R. J. Am. Chem. Soc.
1994, 116, 11578.
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Chem. Soc. 1993, 115, 8855. (b) Matsumoto, T.; Tokitoh, N.; Okazaki, R.
Angew. Chem., Int. Ed. Engl. 1994, 33, 2316. (c) Tokitoh, N.; Matsumoto,
T.; Okazaki, R. J. Am. Chem. Soc. 1997, 119, 2337.
(10) (a) Matsuhashi, Y.; Tokitoh, N.; Okazaki, R. Organometallics 1993,
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(14) For some recent reports on the synthesis of main group element
compounds with unique structures using m-terphenyl ligands, see: (a)
Schiemenz, B.; Power, P. P. Angew. Chem., Int. Ed. Engl. 1996, 35, 2150.
(b) Grigsby, W. J.; Power, P. P. J. Am. Chem. Soc. 1996, 118, 7981. (c)
Simons, R. S.; Power, P. P. J. Am. Chem. Soc. 1996, 118, 11966. We also
developed a new type of bowl-shaped m-terphenyl ligand. (d) Goto, K.;
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(15) For the details of the spectral data, see Supporting Information.
S0002-7863(97)02221-X CCC: $14.00 © 1997 American Chemical Society

Communications to the Editor
J. Am. Chem. Soc., Vol. 119, No. 45, 1997 11125
Figure 1. ORTEP drawing of Tbt(Ditp)SndSe (2c). Selected bond
lengths (Å) and angles (deg): Sn(1)-Se(1), 2.375(3); Sn(1)-C(1), 2.23-
(2); Sn(1)-C(10), 2.20(2); C(1)-Sn(1)-Se(1), 121.6(5); C(10)-Sn-
(1)-Se(1), 115.8(6); C(1)-Sn(1)-C(10), 122.5(7).
Figure 2. ORTEP drawing of Tbt(Ditp)SnSe2 (3). Selected bond
lengths (Å) and angles (deg): Sn(1)-Se(1), 2.528(2); Sn(1)-Se(2),
2.532(3); Se(1)-Se(2), 2.524(4); Se(1)-Sn(1)-Se(2), 59.84(9); Sn-
(1)-Se(1)-Se(2), 60.17(9); Sn(1)-Se(2)-Se(1), 59.99(9); C(1)-Sn-
(1)-C(10), 124.0(6).
protection group having a m-terphenyl skeleton, Ditp (2,2′′-
diisopropyl-m-terphenyl-2′-yl).14 When Tbt(Ditp)SnSe4 1c was
allowed to react with 3 equiv of triphenylphosphine in refluxing
hexane for 2 h under argon, the solution turned deep red, and
observed at -406 ppm assignable to 3. This high-field signal
is characteristic of tin-containing three-membered compounds
(Sn-CdC, -537 ppm;18 Sn-C-S, -365 ppm;19 Sn-Sn-S,
a
119Sn NMR signal was observed at 440 ppm, indicating the
-309 ppm;12c Sn-Sn-Se, -393 ppm;12c Sn-Sn-Te, -594
formation of stannaneselone 2c. Filtration of triphenylphosphine
selenide insoluble in hexane, followed by removal of hexane,
resulted in the isolation of the stable stannaneselone 2c as red
crystals in 84% yield.15 The molecular structure of 2c was
determined by X-ray crystallographic analysis.16 The ORTEP
drawing (Figure 1) shows that the stannaselenocarbonyl unit is
effectively protected by one disil group in Tbt and two isopropyl
groups in Ditp which are directed toward the SndSe bond in
order to avoid the steric repulsion with the Tbt group. The Sn-
Se distance (2.375(3) Å) is approximately 9% shorter than a
Sn-Se single bond length (2.55-2.60 Å)17 and slightly shorter
than that of the Parkin’s terminal selenido complex (2.39 Å).7a
The geometry around the tin atom is trigonal planar, the sum
of the angles being 359.9°, indicative of structural similarity to
a ketone.
ppm20). The 77Se NMR also showed a characteristic high-field
signal at -193 ppm as have been similarly observed for Si-
Si-Se (-287 ppm)12a and Sn-Sn-Se (-378 ppm) ring
systems.12c
These spectral data were consistent with the diselenastan-
nirane structure, but the molecular structure of 3 was finally
established by X-ray crystallographic analysis (Figure 2).21 The
diselenastannirane ring system of 3 forms an equilateral triangle.
It is noted that the Se-Se bond is very long (2.524(4) Å), about
0.2 Å longer than the typical Se-Se single bond22 although the
Sn-Se bond lengths (2.528(2), 2.532(3) Å) are almost equal
to typical Sn-Se bond lengths (2.58 Å).17
In summary, deselenation of tetraselenastannolane 1c bearing
Tbt and Ditp groups gave two novel types of organotin
compounds, i.e., the first kinetically stabilized stannaneselone
2c and first diselenirane derivative, diselenastannirane 3, and
their molecular structures were determined. This successful
deselenation indicates that the dechalcogenation of a tetrachal-
cogenametallolane with appropriate ligands may constitute a
useful synthetic method for compounds with unique structure.
Interestingly, treatment of 1c with 2 equiv of triphenylphos-
phine in hexane at room temperature, followed by removal of
triphenylphosphine selenide gave orange-red crystals of disel-
enastannirane 3 (56%).15 In 119Sn NMR a broad signal was
(16) Crystallographic data for 2c: C51H84SeSi6Sn, M ) 1063.39, triclinic,
a ) 11.939(8) Å, b ) 23.478(5) Å, c ) 11.471(4) Å, R ) 91.86(2)°, â )
112.61(3)°, γ ) 97.45(4)°, V ) 2931(2) Å3, Z ) 2, space group P1h. R(Rw)
) 0.074 (0.086). Full details for the crystallographic analysis of 2c are
described in the Supporting Information.
(17) The average of a Sn-Se single bond in X-Sn-Se-X systems (428
examples) is 2.579 Å (Cambridge Structural Database).
(18) Sita, L. R.; Bickerstaff, R. D. J. Am. Chem. Soc. 1988, 110, 5208.
(19) Ohtaki, T.; Kabe, Y.; Ando, W. Organometallics 1993, 12, 4.
(20) Scha¨fer, A.; Weidenbruch, M.; Saak, W.; Pohl, S.; Marsmann, H.
Angew. Chem., Int. Ed. Engl. 1991, 30, 834.
Acknowledgment. This work was partially supported by a Grant-
in-Aid for Scientific Research No. 05236102 from the Ministry of
Education, Science, Sports and Culture, Japan. M.S. thanks Research
Fellowships of the Japan Society for the Promotion of Science for
Young Scientists. We are also grateful to Shin-etsu Chemical Co., Ltd.
and Tosoh Akzo Co., Ltd. for the generous gift of chlorosilanes and
alkyllithiums, respectively.
(21) Crystals suitable for X-ray structural analysis were obtained by slow
evaporation of a hexane solution of 3 in an argon atmosphere. Crystal data
for 3: C54H91Se2Si6Sn, M ) 1185.44, triclinic, a ) 12.97(1) Å, b ) 22.36-
(1) Å, c ) 12.91(2) Å, R ) 104.54(7)°, â ) 115.86(7)°, γ ) 74.29(6)°, V
) 3205(6) Å3, space group: P1h, Z ) 2, Dc ) 1.228 g cm-3. R(Rw) )
0.072 (0.056). Full details for the crystallographic analysis of 3 are described
in the Supporting Information.
Supporting Information Available: Experimental procedures for
the synthesis and physical properties of 1c, 2c, and 3 and crystal-
lographic data with complete tables of bond lengths, bond angles, and
thermal and positional parameters for 2c and 3 (37 pages). See any
current masthead page for ordering and Internet access instructions.
(22) The average of 115 examples of a Se-Se bond in the C-Se-Se-C
systems is 2.324 Å (Cambridge Structural Database).
JA972221J