synthesis and difluorination of hypervalent tetraaryltellurium(iv)

ICHAC-XI, International Conference on Heteroatom Chemistry
Caen (France), 14-19 June 2015
SYNTHESIS AND DIFLUORINATION OF HYPERVALENT
TETRAARYLTELLURIUM(IV) BEARING
DIMETHYLAMINOPHENYL LIGANDS
Number
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Kotona HAYAKAWA, Sho KOBAYASHI, Mao MINOURA*
Department of Chemistry, College of Science, Rikkyo University,
3-34-1 Nishiikebukuro, Toshima-ku, Tokyo 171-8501, Japan
e-mail: minoura@rikkyo.ac.jp
Hypervalent group 16 element compounds bearing all carbon ligands are less explored
due to their instability. Tetraorganotellurium(IV) having electron-donating ligands have also
been known as unstable compound compared with the electron-withdrawing ligands.
In this paper, we report the synthesis and characterization of tetraaryltellurium,
[Ar4Te, Ar = (H3C)2N-C6H4-] and oxidative difluorination with XeF2. The synthesis of
Ar4Te(IV) was achieved by the reaction of TeCl4 and ArLi which was prepared as yellow solid.
The Ar4Te was isolated as pale yellow crystals and easily reacted with moisture to give the
corresponding telluronium salt. The oxidative difluorination of Ar4Te(IV) was proceeded by the
reaction Ar4Te with XeF2 at -40 °C.
The systematic structural comparison of Ar4Te [Ar = R-C6H4, R = F3C, H, H3C,
(H3C)2N] and 125Te-19F coupling constants of Ar4TeF2 will be discussed.
NMe2
NMe2
Li
TeCl4
NMe2
Et2O
Me2N
Te
XeF2 / MeCN
Me2N
Te
THF
Me2N
F
F
Me2N
NMe2
NMe2