A kinetically stabilized stannanetellone, a tin-tellurium double-bonded compound

Article abstract of DOI:10.1021/om0604627

A kinetically stabilized stannanetellone was synthesized by the telluration of an extremely hindered stannylene with (n-Bu)₃P=Te. The structure of the stannanetellone was determined by X-ray crystallographic analysis.

Full text of DOI:10.1021/om0604627

3552
Organometallics 2006, 25, 3552-3553
A Kinetically Stabilized Stannanetellone, a Tin-Tellurium
Double-Bonded Compound
Tomoyuki Tajima, Nobuhiro Takeda, Takahiro Sasamori, and Norihiro Tokitoh*
Institute for Chemical Research, Kyoto UniVersity, Gokasho, Uji, Kyoto 611-0011, Japan
ReceiVed May 26, 2006
Chart 1
Summary: A kinetically stabilized stannanetellone was synthe-
sized by the telluration of an extremely hindered stannylene with
(n-Bu)3PdTe. The structure of the stannanetellone was deter-
mined by X-ray crystallographic analysis.
Compounds containing a double bond between heavier group
14 and 16 elements,1-4 i.e., heavier congeners of a ketone (called
“heaVy ketones”), are fascinating synthetic targets. We have
already reported the syntheses and isolations of the kinetically
stabilized heavy ketones Tbt(Ar)SidX and Tbt(R)GedX (Ar
) Dip, Tip; R ) Tip, Dis; X ) S, Se, Te) by taking advantage
of an efficient steric protection substituent, the Tbt group.1a-c,h,i
In Chart 1 these abbreviations are defined. Although we have
reported the attempted synthesis of a lead-sulfur double-bonded
compound protected by the Tbt group, Tbt2PbdS, it was found
that the plumbanethione could be generated and trapped at low
temperature but underwent ready isomerization to the corre-
sponding plumbylene (Tbt(TbtS)Pb:) via the migration of the
Tbt group at ambient temperature.5 Therefore, it should be of
great interest whether the compounds having an SndX (X )
S, Se, Te) bond have real existence in a ketone form (R2SndX)
or a stannylene form (R(RX)Sn:). To date, some examples of
thermodynamically stabilized SndX systems such as 1-33 have
been reported (Chart 2), but they are highly perturbed by the
electron donation from the neighboring nitrogen atoms, as
evidenced by their high-field chemical shifts in their 119Sn NMR
spectra. On the other hand, we recently reported the synthesis
Chart 2
and isolation of the kinetically stabilized stannanechalcogenones
Tbt(Ditp)SndS4c and Tbt(Ditp)SndSe4b,c (Chart 1), examples
of the intrinsic nature of tin-chalcogen double-bond com-
pounds. To extend this chemistry, we became interested in the
synthesis of an as yet unknown, kinetically stabilized tin-
tellurium double-bonded compound (stannanetellone). The
elucidation of properties of a stannanetellone is important for
the systematic understanding of the heavy ketones.
We present here the synthesis and isolation of a stable
stannanetellone by taking advantage of the kinetic stabilization
afforded by the combination of 2,6-bis[bis(trimethylsilyl)-
methyl]-4-[tris(trimethylsilyl)methyl]phenyl (Bbt) and 2,2′′,4,4′′-
tetraisopropyl-m-terphenyl-2′-yl (Titp) substituents on the tin
atom, together with a crystallographic structural analysis.
Stannylene 5, a possible precursor for the synthesis of a stable
stannanetellone, was readily obtained by the reduction of the
corresponding dibromostannane 4 with KC8 in benzene at room
temperature (Scheme 1).6 Stannylene 5 was isolated as air- and
moisture-sensitive deep purple crystals in 52% yield. The 119Sn
NMR spectrum of 5 in C6D6 showed only one signal at 1657
ppm relative to tetramethylstannane (δ 0), which is a charac-
teristic chemical shift of a divalent organotin compound.7 The
molecular structure of 5 was determined by X-ray crystal-
lographic analysis (Figure S1, Supporting Information).
The telluration of 5 using (n-Bu)3PdTe as a tellurium
source1c,8 was achieved at -40 °C. Stannanetellone 6 was
isolated as light green crystals by recrystallization from hexane
in 73% yield (Scheme 1). Stannanetellone 6 was very sensitive
toward moisture but surprisingly stable toward light, in sharp
* To whom correspondence should be addressed. E-mail: tokitoh@
boc.kuicr.kyoto-u.ac.jp.
(1) For reviews, see: (a) Tokitoh, N.; Okazaki, R. AdV. Organomet.
Chem. 2001, 47, 121. (b) Okazaki, R.; Tokitoh, N. Acc. Chem. Res. 2000,
33, 625. (c) Tokitoh, N.; Matsumoto, T.; Okazaki, R. Bull. Chem. Soc. Jpn.
1999, 72, 1665. (d) Escudie´, J.; Ranaivonjatovo, H. AdV. Organomet. Chem.
1999, 44, 113. (e) Tokitoh, N.; Okazaki, R. In The Chemistry of Organic
Silicon Compounds; Rappoport, Z., Apeloig, Y., Eds.; Wiley: New York,
1998; Vol. 2, p 1063. (f) Barrau, J.; Rima, G. Coord. Chem. ReV. 1998,
178-180, 593. (g) Baines, K. M.; Stibbs, W. G. AdV. Organomet. Chem.
1996, 39, 275. For the silanetellone and germanetellone: (h) Tokitoh, N.;
Sadahiro, T.; Hatano, K.; Sasaki, T.; Takeda, N.; Okazaki, R. Chem. Lett.
2002, 31, 34. (i) Tokitoh, N.; Matsumoto, T.; Okazaki, R. J. Am. Chem.
Soc. 1997, 119, 2337.
(2) Other double-bonded compounds between group 14 and 16 ele-
ments: (a) Ding, Y.; Roesky, H. W.; Noltemeyer, M.; Schmidt, H.-G. J.
Am. Chem. Soc. 2001, 124, 8542. (b) Pineda, L. W.; Jancik, V.; Roesky,
H. W.; Herbst-Irmer, R. Angew. Chem., Int. Ed. 2004, 43, 5534. (c) Saur,
I.; Garcia, A.; Barrau, J. Appl. Organomet. Chem. 2005, 19, 414.
(3) (a) Kuchta, M. C.; Parkin, G. J. Am. Chem. Soc. 1985, 107, 8272.
(b) Leung, W.-P.; Kwok, W.-H.; Law, L. T. C.; Zhou, Z.-Y.; Mak, T. C.
W. J. Chem. Soc., Chem. Commun. 1996, 505. (c) Kuchta, M. C.; Parkin,
G. Coord. Chem, ReV. 1998, 176, 323. (d) Leung, W.-P.; Kwok, W.-H.;
Zhou, Z.-Y.; Mak, T. C. W. Organometallics 2000, 19, 296. (e) Chivers,
T.; Schatte, G. Chem. Commun. 2004, 2264. (f) Chivers, T.; Clark, T. J.;
Krahn, M.; Parvez, M.; Schatte, G. Eur. J. Inorg. Chem. 2003, 1857. (g)
Chivers, T.; Eisler, D. J. Angew. Chem., Int. Ed. 2004, 43, 6686. (h) Chivers,
T.; Eisler, D. J.: Ritch, J. S. Z. Anorg. Allg. Chem. 2004, 630, 1941.
(4) (a) Matsuhashi, Y.; Tokitoh, N.; Okazaki, R. Organometallics 1993,
12, 2573. (b) Saito, M.; Tokitoh, N.; Okazaki, R. J. Am. Chem. Soc. 1997,
119, 11124. (c) Saito, M.; Tokitoh, N.; Okazaki, R. J. Am. Chem. Soc.
2004, 126, 15572.
(6) Reduction of dibromostannanes: (a) Saito, M.; Tokitoh, N.; Okazaki,
R. Organometallics 1995, 14, 3620.
(7) (a) Saito, M.; Tokitoh, N.; Okazaki, R. J. Am. Chem. Soc. 1993, 115,
2065. (b) Kira, M.; Yauchibara, R.; Hirano, R.; Kabuto, C.; Sakurai, H. J.
Am. Chem. Soc. 1991, 113, 7785. (c) Zilm, K. W.; Lawless, G. A.; Merrill,
R. M.; Millar, J. M.; Webb, G. G. J. Am. Chem. Soc. 1987, 108, 7236. (d)
Weidenbruch, M.; Schlaefke, J.; Scha¨fer, A.; Peters, K.; von Schnering, H.
G.; Marsmann, H. Angew. Chem., Int. Ed. 1994, 33, 1846. (e) Simons, R.
S.; Pu, L.; Olmstead, M. M.; Power, P. P. Organometallics 1997, 16, 1920.
(5) Kano, N.; Tokitoh, N.; Okazaki, R. Organometallics 1997, 16, 2748.
10.1021/om0604627 CCC: $33.50 © 2006 American Chemical Society
Publication on Web 06/17/2006

Communications
Organometallics, Vol. 25, No. 15, 2006 3553
Scheme 1
contrast to the carbon analogues, telluroketones, which are
known to be extremely labile even under fluorescent light.9 The
UV-vis spectrum of 6 in hexane showed two absorption
maxima at 436 (ꢀ ) 1400) and 646 nm (ꢀ ) 80), which were
assigned to the π-π* and n-π* electron transitions for the
SndTe chromophore, respectively.10 The λmax value of 646 nm
for the n-π* transition is larger than those for any of the other
corresponding heavy ketones, Tbt(Ar)MdX (M ) Si, Ge; X )
S, Se, Te) and Tbt(Ar)SndX (X ) S, Se), and this result is
consistent with the tendency that the n-π* absorptions of heavy
ketones are systematically red-shifted with increasing atomic
number of the group 14 and 16 elements.1
Figure 1. ORTEP drawing of Bbt(Titp)SndTe (6) with thermal
ellipsoid plots (50% probability). Hydrogen atoms and a hexane
molecule are omitted for clarity.
The NMR spectra of stannanetellone 6 displayed the char-
acteristic features expected of a tin-tellurium double-bond
compound. That is, the 119Sn NMR spectrum showed only one
broad signal at 282 ppm,11 which could be assigned to the sp2
tin atom of the stannanetellone 6. In contrast to the case for 1c
and 2c (-350 and -397 ppm),3d,h the low-field chemical shift
of 6 was characteristic of a double-bonded compound containing
a tin atom.12 The 125Te NMR spectrum of 6 showed a singlet
signal at 1007 ppm, similar to those of germanetellones reported
earlier (1143 and 1009 ppm in C6D6).2
Scheme 2
The structural parameters of stannanetellone 6 were defini-
tively determined by X-ray crystallographic analysis at -170
°C (Figure 1).13 One can see that the SndTe bond of 6 is
effectively protected by the o-CH(SiMe3)2 units of the Bbt group
and an o-isopropyl group of the Titp group. The Sn1-Te1 bond
distance (2.5705(6) Å) is shorter by about 6.5% than the average
for Sn-Te single bonds14 and is in good agreement with the
calculated SndTe bond length of Ph2SndTe (2.589 Å). The
length of the SndTe bond of 6 was slightly shorter than those
of 1c and 2c (2.618(1) and 2.603(1) Å, respectively).3d,h The
tin atom of 6 was found to have a completely trigonal planar
geometry (the sum of the angles being 359.68°), indicating the
structural similarity to the carbonyl carbon atoms of ketones.
Stannanetellone 6 was found to undergo some addition
reactions with small molecules (Scheme 2). Hydrolysis of 6 gave
dihydroxystannane 8, most probably via intermediate 7. Mesito-
nitrile oxide reacted as a 1,3-dipole reagent with 6 to give the
expected [2 + 3] cycloadduct 9. The reaction of 6 with dimethyl
acetylenedicarboxylate (DMAD) resulted in the formation of
the corresponding [2 + 2] cycloadduct 10. The reaction mode
of 6 was found to be similar to those of other heavy ketones.1,4
(8) For recent examples of the use of (n-Bu)3PdTe as a tellurium source,
see: (a) Sasamori, T.; Mieda, E.; Takeda, N.; Tokitoh, N. Angew. Chem.,
Int. Ed. 2005, 44, 3717. (b) Zhang, T.; Piers, W. E.; Parvez, M. Can. J.
Chem. 2002, 80, 1524. (c) Knight, L. K.; Piers, W. E.; McDonald, R. Chem.
Eur. J. 2000, 6, 4322.
(9) Minoura, M.; Kawashima, T.; Okazaki, R. J. Am. Chem. Soc. 1993,
115, 7019.
(10) Assignments of the observed two absorption maxima for 6 are
reasonably supported by the TDDFT(B3LYP) calculations for Ph2SndTe
(406 (π-π*) and 612 nm (n-π*)). (Figure S4, Supporting Information).
(11) Although the coupling constant between 119Sn and 125Te is thought
to be diagnostic of the degree of the multiple-bond character, it was not
observed by 119Sn and 125Te NMR spectroscopy.
(12) SndSn: (a) Goldberg, D. E.; Harris, D. H.; Lappert, M. F.; Thomas,
K. M. J. Chem. Soc., Chem. Commun. 1976, 261. (b) Wiberg, N.; Lerner,
H.-W.; Vasisht, S.-K.; Wagner, S.; Karaghiosoff, K.; No¨th, H.; Poikwar,
W. Eur. J. Inorg. Chem. 1999, 1211. SndC: (c) Meyer, H.; Baum, G.;
Massa, W.; Berger, S.; Berndt, A. Angew. Chem., Int. Ed. Engl. 1987, 26,
546. (d) Anselme, G.; Ranaivonjatovo, H.; Escudie´, J.; Couret, C.; Satge´,
J. Organometallics 1992, 11, 2748. (e) Mizuhata, Y.; Takeda, N.; Sasamori,
T.; Tokitoh, N. Chem. Commun. 2005, 5876. SndSi: (f) Sekiguchi, A.;
Izumi, R.; Lee, V. Y.; Ichinohe, M. J. Am. Chem. Soc. 2002, 124, 14822.
SndGe: (g) Chaubon, M. A.; Escudie´, J.; Ranaivonjatovo, H.; Satge, J. J.
Chem. Soc., Chem. Commun. 1996, 2621. (h) Sekiguchi, A.; Izumi, R.;
Lee, V. Y.; Ichinohe, M. Organometallics 2003, 22, 1483. (i) Scha¨fer, A.;
Saak, W.; Weidenbruch, M. Organometallics 2003, 22, 215. SndP: (j)
Couret, C.; Escudie´, J.; Satge´, J.; Raharinirina, A.; Andrriamizaka, J. D. J.
Am. Chem. Soc. 1985, 107, 8280. (k) Ranaivonjatovo, H.; Escudie´, J.;
Couret, C.; Satge´, J. J. Chem. Soc., Chem. Commun. 1992, 1047. SndN:
(l) Ossig, G.; Meller, A.; Freitag, S.; Herbst-Irmer, R. J. Chem. Soc., Chem.
Commun. 1993, 497.
Acknowledgment. This work was partially supported by
Grants-in-Aid for Scientific Research (Nos. 12CE2005, 14078213,
14204064, 16000754, and 17GS0207), the 21st Century COE
on Kyoto University Alliance for Chemistry (Novel Organic
Materials Creation & Transformation Project), and the Nano-
technology Support Project from the Ministry of Education,
Culture, Sports, Science, and Technology of Japan. T.T. is
grateful for Research Fellowships of the Japan Society for the
Promotion of Science for Young Scientists.
Supporting Information Available: Text, tables, and figures
giving experimental details, theoretical calculations, and 1H NMR
spectra for 5, 6, 9, and 10 and CIF files giving X-ray structural
data for 5, 6, 8, and 10. This material is available free of charge
via the Internet at http://pubs.acs.org.
(13) Crystallographic data for 6: C66H118Si7SnTe, Mr ) 1354.52,
OM0604627
monoclinic, space group P21/c, a ) 13.871(4) Å, b ) 22.050(6) Å, c )
23.776(6) Å, â ) 90.492(3)°, V ) 7272(3) Å3, Z ) 4, Dc ) 1.237 g cm-3
,
µ ) 0.895 cm-1, R1 ) 0.0362, wR2(all data) ) 0.1142. GOF ) 1.244,
largest diff peak and hole 1.718 and -0.996 e Å-3 (around the Te atom).
(14) The average of Sn-Te single bonds in X-Sn-Te-X systems (26
examples) is 2.751 Å (Cambridge Structural Database).