Telluradistibirane and telluradibismirane: Three-membered heterocycles of heavier main group elements

Article abstract of DOI:10.1002/anie.200462122

(Chemical Equation Presented) Metal triangles: The first stable telluradistibirane and telluradibismirane derivatives (see structure) have been successfully synthesized by the reaction of an overcrowded distibene (BbtSb=SbBbt) and dibismuthene (BbtBi=BiBb

Full text of DOI:10.1002/anie.200462122

Angewandte
Chemie
[2 + 1] cycloaddition reactions. In the case of heavier Group
14 elements, selenadimetalliranes and telluradimetalliranes
(Ch-M-M three-membered ring compounds; Ch = Se, Te,
M = Si, Sn) have been successfully synthesized by chalcoge-
nation reactions of the corresponding kinetically stabilized
=
dimetallenes (M M double-bond compounds) using elemen-
tal chalcogens.[4] There has also been much interest in doubly
bonded compounds between heavier Group 15 elements, that
is, heavier congeners of azo compounds. We synthesized a
series of kinetically stabilized distibene (ArSb SbAr)[5,6] and
=
[5,7]
=
dibismuthene (ArBi BiAr)
compounds by using 2,4,6-
tris[bis(trimethylsilyl)methyl]phenyl (Tbt) and 2,6-bis[bis(tri-
methylsilyl)methyl]-4-[tris(trimethylsilyl)methyl]phenyl
(Bbt) groups as effective steric protection groups. However,
whereas no tellurirane containing two heavier Group 15
elements was obtained from the tellurization reaction of
[8]
=
=
BbtP PBbt using elemental Te or (nBu)3P Te, selenadi-
phosphiranes[8,9] and a selenadistibirane[10] were synthesized
by the selenization reaction of the corresponding diphos-
Main Group Chemistry
=
phene (Mes*P PMes* (Mes* = 2,4,6-tri-tert-butylphenyl),
=
=
Telluradistibirane and Telluradibismirane: Three-
Membered Heterocycles of Heavier Main Group
Elements**
BbtP PBbt, etc.) and distibene (BbtSb SbBbt), respectively.
Herein, we report the tellurization reaction of the kinetically
=
stabilized distibene BbtSb SbBbt (1) and dibismuthene
=
BbtBi BiBbt (2), which led to the formation of novel three-
membered heterocycles, that is, the first stable telluradistibir-
ane and telluradibismirane, respectively.
Takahiro Sasamori, Eiko Mieda, Nobuhiro Takeda, and
Norihiro Tokitoh*
=
The reaction of BbtBi BiBbt (2, 30 mg, 0.02 mmol),
which was readily prepared by reductive coupling of BbtBiBr2
with Mg in almost quantitative yield,[5] with an excess amount
of elemental tellurium (26 mg, 10 equiv) in [D6]benzene
solution was performed in the hope of generating a tellura-
dibismirane derivative. After heating the mixture at 608C for
72 h, then at 808C for 72 h, and finally at 1008C for 72 h, 2
The chemistry of three-membered heterocycles has been
widely explored in organic chemistry from the viewpoint of
their unique structures and properties, which are attributed to
their strained skeletons.[1,2] Although numerous papers have
been published on the theory, preparation, and applications of
three-membered heterocycles containing one heteroatom
such as nitrogen, oxygen, or sulfur, only very few examples
of three-membered ring compounds containing heavier
chalcogen atoms such as selenium or tellurium have appeared
to date.[3] In addition, three-membered ring systems com-
posed of three heavier heteroatoms are also scarce, most
likely owing to the instability of these systems. To synthesize
such three-membered heterocycles that incorporate selenium
or tellurium together with other heavier heteroatoms in their
skeletons, one effective method should be the chalcogenation
of highly reactive heavier double-bond compounds by formal
1
disappeared completely as judged by the H NMR spectra.
However, not the desired telluradibismirane but only the
ditelluride 3 (Bbt-Te-Te-Bbt) was obtained (12 mg, 42%) as
green crystals after purification by GPLC. The structure of 3
was determined by spectroscopic data (1H, 13C, 125Te NMR,
FAB-MS) and X-ray crystallographic analysis.[11] Although
mechanism for the formation of 3 is not clear at present, 3 was
most likely generated by over-tellurization of 2 under severe
conditions such as heating at 60–1008C, which would be
required to dissolving elemental tellurium in benzene.
=
Since nBu3P Te has been known to function as a
tellurization reagent under mild conditions,[12] we selected
=
nBu3P Te as an alternative tellurium source for the telluriza-
[*] Dr. T. Sasamori, E. Mieda, Dr. N. Takeda, Prof. Dr. N. Tokitoh
Institute for Chemical Research, Kyoto University
Gokasho, Uji, Kyoto 611-0011 (Japan)
tion of 1 and 2. When a solution of 2 (49 mg, 0.03 mmol) in
benzene (2.0 mL) was mixed with two equivalents of nBu3P
Te (23 mg, 0.06 mmol) at room temperature, telluradibismir-
ane 5, in the form of an insoluble brown powder, precipitated
from the reaction mixture (Scheme 1). After the suspension
=
Fax: (+81)774-38-3209
E-mail: tokitoh@boc.kuicr.kyoto-u.ac.jp
[**] This work was supported by Grants-in-Aid for Scientific Research
(Nos. 14078213 and 16750033), COE Research on “Elements
Science” (No. 12CE2005), and 21st Century COE of Kyoto University
Alliance for Chemistry from the Ministry of Education, Culture,
Sports, Science and Technology, Japan. This manuscript was written
at TU Braunschweig during the tenure of a von Humboldt Senior
Research Award of one of the authors (N. Tokitoh), who is grateful
to the von Humboldt Stiftung for their generosity and to Prof.
Reinhard Schmutzler and Prof. Wolf-Walther du Mont for their warm
hospitality.
Scheme 1. Synthesis of telluradipnictiranes.
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DOI: 10.1002/anie.200462122
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was left to stand for 2 h, 5 was isolated as a pure material by
filtration followed by washing with hexane (23.3 mg,
0.013 mmol, 43%). In this case, the tellurization reaction of
2 occurred at room temperature probably due to the fact that
=
nBu3P Te is more soluble than elemental tellurium. In
addition, no ditelluride 3 was observed in the 1H NMR
spectrum of the crude mixture. Distibene 1 was also tellurized
by this method, giving the corresponding telluradistibirane 4.
=
Treatment of 1 with nBu3P Te under conditions similar to
those applied to 2 afforded 4 as an orange powder in 50%
yield. Three-membered ring compounds were obtained by the
tellurization reaction of 1 and 2, in contrast to the case of
sulfurization reactions of 1, which resulted in the formation of
corresponding four-, five-, and six-membered ring com-
pounds.[13] The formation of 4 and 5 is worthy of note not
only as the synthesis of new members of three-membered
heterocycles, but also as a new finding on the reactivity of
distibenes and dibismuthenes toward the tellurization reac-
tion.
Figure 1. Molecular structure of 5 (ORTEP drawing; thermal ellipsoid
plot (50% probability)).
The telluradistibirane 4 was found to be thermally stable
in [D6]benzene solution up to 1408C, and showed satisfactory
1H and 13C NMR spectral data. In addition, no change was
observed in [D6]benzene solution at 608C under photo-
irradiation with a 100-W high-pressure Hg lamp. Although
the telluradibismirane 5 was stable under ambient conditions,
heating a solution of 5 in [D6]benzene at 808C for 1 h afforded
a trace amount of ditelluride 3. After the solution was heated
at 1008C for 1 h, 5, 2, and 3 were observed in the ratio of
1:0.2:0.1. Additional heating of the solution at 1108C for 1 h
gave an unidentified compound (X) together with 2 and 3 as
the final products in a ratio of X:2:3 = 1:2:2 as judged by
1H NMR spectroscopy. Unfortunately, the reaction mecha-
nism and the structure of the final product for the decom-
position process of 5 are still unclear owing to the instability
of compound X during the purification procedure. On the
other hand, 125Te NMR spectra of 4 measured in [D8]toluene
show a signal at d = À622.3 ppm within an upfield region,
which is characteristic of such three-membered ring com-
Figure 2. Selected bond lengths [ꢀ] and bond angles [8] of 4 and 5.
Values in braces are calculated structural parameters for Mes-substi-
tuted model compounds 6 and 7.
À
À
2.8833(6), Sb Te 2.7607(7), 2.7719(6); 5: Bi Bi 3.0388(3),
À
Bi Te 2.8546(4), 2.8648(4) ꢀ) that are comparable with
previously reported values for the respective single bonds.[16]
In addition, calculated structural parameters obtained by
structural optimization (B3LYP) for the model compounds 6
and 7 supported the experimentally observed values obtained
for the central three-membered-ring skeletons of 4 and 5.
These experimental and theoretical studies on the structures
of 4 and 5 indicate that the telluradistibirane and telluradi-
bismirane feature three-membered-ring character (A) rather
than the p-complex character (B) as shown in Scheme 2.
Interestingly, the telluradisilirane 8, which is reported to be
pounds. For example, some telluradisilirane (dTe
=
À784 ppm)[4a] and telluradistannirane (dTe = À903 ppm)[4b]
derivatives were reported to show their 125Te NMR signals
in an up-field region, similar to the case of 4. In addition, the
125Te NMR chemical shift of dimesityltelluradistibirane (6), a
model compound for 4, was computed as d = À700 ppm by a
GIAO calculation, which supports the experimentally
observed chemical shift of 4. Unfortunately, no signal was
observed in the 125Te NMR spectrum of 5 probably due to
considerable peak broadening caused by the adjacent two
bismuth atoms having nuclear spins of 9/2.
=
obtained by the reaction of Mes2Si SiMes2 with elemental
tellurium, features p-complex character (B) rather than the
three-membered-ring character (A).[4a] It should be noted
The molecular structures of 4 and 5 were determined by
X-ray crystallographic analysis.[14] The structure of telluradi-
bismirane 5 is shown in Figure 1 as a representative. The
selected bond lengths and angles of 4 and 5 are depicted in
Figure 2 together with the optimized structural parameters of
model compounds, dimesityltelluradistibirane (6) and dime-
sityltelluradibismirane (7).[15] In both 4 and 5, the two Bbt
groups are oriented trans with regard to the central three-
membered rings. The tellurirane skeletons of 4 and 5 are
À
almost isosceles triangles with bond lengths (4: Sb Sb
Scheme 2. Structures of telluriranes.
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Chemie
dented heavier congeners of cycloproparene derivatives, see:
that the structural features of the corresponding tellurirane
derivatives of heavier Group 15 elements differ from those of
heavier group 14 elements.
In summary, we have synthesized the first stable tellura-
distibirane, 4, and telluradibismirane, 5, by a tellurization
a) K. Hatano, N. Tokitoh, N. Takagi, S. Nagase, J. Am. Chem.
Soc. 2000, 122, 4829; b) N. Tokitoh, K. Hatano, T. Sasaki, T.
Sasamori, N. Takeda, N. Takagi, S. Nagase, Organometallics
2002, 21, 4309; c) T. Tajima, K. Hatano, T. Sasaki, T. Sasamori, N.
Takeda, N. Tokitoh, Chem. Lett. 2003, 32, 220; d) T. Tajima, K.
Hatano, T. Sasaki, T. Sasamori, N. Takeda, N. Tokitoh, N. Takagi,
S. Nagase, J. Organomet. Chem. 2003, 686, 118. In addition,
unique three-membered ring systems of heavier Group 14
elements have been reported as a review, see: A. Sekiguchi,
V. Y. Lee, Chem. Rev. 2003, 103, 1429.
=
reaction of the reactive double-bond systems, BbtSb SbBbt
=
=
and BbtBi BiBbt, by using (nBu)3P Te as a tellurization
reagent. We have demonstrated here that telluradistibirane
and telluradibismirane derivatives, which are three-mem-
bered ring compounds composed of much heavier elements,
Sb, Bi, and Te, can be isolated without any oligomerization by
using an appropriate steric protecting group and synthetic
method. Further investigation of the physical and chemical
properties of the newly obtained three-membered ring
systems 4 and 5 is currently in progress.
[3] For a review of selenirenes and tellurirenes, see: N. Tokitoh, W.
Ando, N. Choi in Comprehensive Heterocyclic Chemistry II
(Eds.: A. R. Katritzky, C. W. Rees, E. F. Scriven), Vol. 1A (Ed.:
A. Padwa), Pergamon, Oxford, 1996, pp. 173 – 240; N. Tokitoh,
W. Ando in Science of Synthesis, Houben-Weyl Methods of
Molecular Transformations, Vol. 9 (Eds.: D. Belllus, S. V. Ley, R.
Noyori, M. Regitz, E. Schaumann, I. Shinkai, E. J. Thomas, B. M.
Trost, M. Regitz, G. Maas), Thieme, Stuttgart, 2001, pp. 61 – 65.
[4] a) R. P. K. Tan, G. R. Gillette, D. R. Powell, R. West, Organo-
metallics 1991, 10, 546; b) A. Schꢁfer, M. Weidenbruch, W. Saak,
S. Pohl, H. Marsmann, Angew. Chem. Int. 1991, 103, 873; Angew.
Chem. Int. Ed. Engl. 1991, 30, 834; c) A. Schꢁfer, M. Weiden-
bruch, W. Saak, S. Pohl, H. Marsmann, Angew. Chem. 1991, 103,
978; Angew. Chem. Int. Ed. Engl. 1991, 30, 962.
[5] T. Sasamori, Y. Arai, N. Takeda, R. Okazaki, Y. Furukawa, M.
Kimura, S. Nagase, N. Tokitoh, Bull. Chem. Soc. Jpn. 2002, 75,
661.
[6] N. Tokitoh, Y. Arai, T. Sasamori, R. Okazaki, S. Nagase, H.
Uekusa, Y. Ohashi, J. Am. Chem. Soc. 1998, 120, 433.
[7] N. Tokitoh, Y. Arai, R. Okazaki, S. Nagase, Science 1997, 277, 78.
[8] T. Sasamori, N. Takeda, N. Tokitoh, J. Phys. Org. Chem. 2003, 16,
450.
Experimental Section
=
4: Addition of nBu3P Te (33 mg, 0.10 mmol) to a solution of 1
(70.4 mg, 0.05 mmol) in benzene (2 mL) at room temperature, led to
the immediate precipitation of an orange powder. After the reaction
mixture had been left to stand for 2 h, telluradistibirane 4 was
separated by filtration, and then further purified by GPLC (40 mg,
0.025 mmol, 50%). 4: orange crystals, m.p. 1618C (decomp);
1H NMR (300 MHz, [D6]benzene): d = 0.33 (s, 54H), 0.36 (s, 36H),
0.37 (s, 36H), 2.87 (s, 4H), 6.96 ppm (s, 4H); 13C NMR (75 MHz,
[D6]benzene): d = 2.09 (q), 2.28 (q), 5.65 (q), 22.21 (s), 37.69 (d),
126.90 (d), 138.33 (s), 145.83 (s), 150.88 ppm (s); 125Te NMR (94 MHz,
[D8]toluene): d = À622.3 ppm; UV/Vis (hexane): lmax (e) = 458 (680),
390 (3100), 346 nm (8500); HRMS (FAB): m/z: 1619.4440([M+H]+),
calcd for C60H135121Sb2Si14130Te ([M+H]+): 1619.4472; elemental
analysis calcd (%) for C60H134Sb2Si14Te: C 44.48, H 8.34; found: C
44.23, H 8.23.
[9] M. Yoshifuji, K. Shibayama, N. Inamoto, Chem. Lett. 1984, 603.
[10] N. Tokitoh, T. Sasamori, R. Okazaki, Chem. Lett. 1998, 725.
1
[11] 3: dark-green crystals, m.p. 238.6–240.08C (decomp); H NMR
=
5: nBu3P Te (23 mg, 0.06 mmol) was added to a solution of 2
(300 MHz, [D6]benzene): d = 0.34 (s, 72H), 0.35 (s, 54H), 3.05 (s,
4H), 7.05 ppm (s, 4H); 125Te NMR (94 MHz, [D6]benzene): d =
328.7 ppm; HRMS (FAB): m/z: 1505.5448 ([M+H]+), calcd for
C60H135Si14128Te130Te 1505.5443; elemental analysis calcd (%) for
C60H134Si14Te2: C 47.91, H 8.98; found: C 48.20, H 9.05; the X-ray
crystallographic analysis of 3 will be described elsewhere.
[12] For example, the synthesis of an alkylidenetelluragermirane
derivative with tributylphosphine telluride has been reported;
see: K. Kishikawa, N. Tokitoh, R. Okazaki, Organometallics
1997, 16, 5127.
(49.0 mg, 0.03 mmol) in benzene (2 mL) at room temperature. The
color of the reaction mixture immediately changed to dark brown.
After the resulting suspension had been stirred for 2 h, the reaction
mixture was filtered, and the residue was washed with hexane
(20 mL) to afford brown crystals of telluradibismirane 5 (23.3 mg,
0.013 mmol, 43%). 5: brown crystals, m.p. 1568C (decomp); 1H NMR
(400 MHz, [D6]benzene): d = 0.33 (s, 36H), 0.34 (s, 54H), 0.36 (s,
36H), 2.29 (s, 4H), 7.20 ppm (s, 4H); 13C NMR (100 MHz, [D6]ben-
zene): d = 2.31 (q), 2.41 (q), 5.65 (q), 22.10 (s), 43.15 (d), 126.54 (d),
145.08 (s), 151.68 (s), 161.38 ppm (s); UV/Vis (hexane): lmax (e) = 521
(2100), 450 (3200), 338 nm (18700); HRMS (FAB): m/z: 1795.6004
([M+H]+), calcd for C60H135Bi2Si14130Te ([M+H]+): 1795.6004; ele-
mental analysis calcd (%) for C60H134Bi2Si14 Te: C 40.16, H 7.53;
found: C 40.12, H 7.48.
[13] Treatment of 1 with S8 in benzene afforded the corresponding
1,3,2,4-dithiadistibolane,
1,2,4,3,5-trithiadistibolane,
and
1,2,3,5,4,6-tetrathiadistibinane derivatives; see: T. Sasamori, E.
Mieda, N. Takeda, N. Tokitoh, Chem. Lett. 2004, 33, 104.
[14] Crystal data for 4 (C60H134Sb2Si14Te): Mr = 1620.03, T= 103(2) K,
monoclinic, C2/c (no. 15), a = 38.348(3), b = 9.2753(5), c =
Received: September 27, 2004
Revised: December 12, 2004
Published online: May 20, 2005
47.689(3) ꢀ, b = 92.732(3)8, V= 16943.2(18) ꢀ3, Z = 8, 1calcd
=
1.270 gcmÀ3, m = 1.205 mmÀ1, l = 0.71070 ꢀ, 2qmax = 50.0, 51832
measured reflections, 13961 independent reflections, 793 refined
parameters, GOF = 1.159, R1 = 0.0658 and wR2 = 0.1420 [I >
2s(I)], R1 = 0.0757 and wR2 = 0.1480 (for all data), largest
difference peak and hole 3.312 and À2.129 eꢀÀ3, respectively,
(around Sb and Te atoms); crystal data for 5 (C60H134Bi2Si14Te):
Mr = 1794.49, T= 103(2) K, monoclinic, C2/c (no. 15), a =
39.199(2), b = 9.2798(3), c = 47.120(2) ꢀ, b = 92.517(2)8, V=
17123.9(13) ꢀ3, Z = 8, 1calcd = 1.392 gcmÀ3, m = 4.666 mmÀ1, l =
0.71070 ꢀ, 2qmax = 51.0, 69668 measured reflections, 15682
independent reflections, 819 refined parameters, GOF = 1.121,
R1 = 0.0381 and wR2 = 0.0717 [I > 2s(I)], R1 = 0.0433 and wR2 =
0.0736 (for all data), largest difference peak and hole 2.230 and
À1.456 eꢀÀ3, respectively, (around Bi and Te atoms). CCDC-
Keywords: chalcogenides · heterocycles · multiple bonds ·
.
strained molecules · X-ray diffraction
[1] For a review of three-membered heterocycles, see: Comprehen-
sive Heterocyclic Chemistry II (Eds.: A. R. Katritzky, C. W. Rees,
E. F. Scriven), Vol. 1A (Ed.: A. Padwa), Pergamon, Oxford,
1996.
[2] We have recently reported the synthesis and structures of the
heavier analogues of a cyclopropabenzene, sila- and germa
cyclopropabenzenes and bis(silacyclopropa)benzenes, unprece-
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Communications
249239 (4) and -249238 (5) contains the supplementary crystallo-
graphic data for this paper. These data can be obtained free of
charge from the Cambridge Crystallographic Data Centre via
www.ccdc.cam.ac.uk/data_request/cif. The intensity data were
collected on a Rigaku/MSC Mercury CCD diffractometer. The
structure was solved by direct methods (SHELXS-97) and
refined by full-matrix least-squares procedures on F2 for all
reflections (SHELXL-97).
[15] Structural optimization for 6 and 7 was carried out by using the
Gaussian 98 program with density functional theory at the
B3LYP level. The triple zeta basis sets ([3s3p]) for Sb and Bi, and
double zeta basis sets ([2s2p]) for Te were used with effective
core potentials; the 6-31G* basis set was used for C and H.
À
À
[16] Sb Sb and Bi Bi bond lengths are reported as 2.837 and
À
2.990 ꢀ, respectively, in Ph2E EPh2, see: H. Bꢂrger, R. Eujen,
G. Becker, O. Mundt, M. Westerhausen, C. Witthauer, J. Mol.
Struct. 1983, 98, 265; F. Calderazzo, R. Poli, G. Pelizzi, J. Chem.
Soc. Dalton Trans. 1984, 11, 2365; a few examples of compounds
À
containing an E Te bond (E = Sb, Bi) have been reported to
À
date; Sb Te bond lengths observed in a cluster compound are in
the range of 2.75 – 72.78 ꢀ, see: S. S. Dhingra, R. C. Haushalter,
À
J. Am. Chem. Soc. 1994, 116, 3651; Bi Te bond lengths observed
in (Dis2Bi)2Te (Dis = CH(SiMe3)2) are 2.872 and 2.889 ꢀ, see:
H. J. Breunig, I. Ghesner, E. Lork, J. Organomet. Chem. 2002,
664, 130.
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