- 2,2'-Bitellurophene and 2,2':5',2''-Tertellurophene as Novel High Homologues of Tellurophene
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The title heterocycles were prepared from tellurophene, and their spectroscopic and electrochemical properties were systematically compared together with those of other chalcogenophene congeners.Their electropolymerizations gave poly(bitellurophene) and poly(tertellurophene) as black films, which both had higher electrical conductivities than poly(tellurophene) similarly obtained.
- Inoue, Shinobu,Jigami, Tetsuya,Nozoe, Hiroshi,Otsubo, Tetsuo,Ogura, Fumio
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- Syntheses, spectroscopic properties, and polymerizations of 2,2'- bitellurophene, 2,2':5',2'',-tertellurophene, and related hybrid terchalcogenophenes
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2,2'-Bitellurophene, 2,2':5',2''-tertellurophene, and related hybrid terchalcogenophenes have been synthesized as a novel extended series of tellurophene homologues. The molecular and crystal structures of 2,2'- bitellurophene were elucidated by an X-Ray crystallographic analysis and compared with those of 2,2'-bithiophene and 2,2'-biselenophene. The molecular structure adopts an almost completely planar transoid conformation, as seen for the other bichalcogenophenes, but the crystal structure is quite different, comprising a unique herringbone-type of molecular packing with heteroatomic interactions of tellurium. The electronic absorption spectra of the tellurophenes are characterized by strong π-π* transitions which appear in the longer wavelength region than those of thiophene and selenophene analogues and are systematically red-shifted with the increasing number of the conjugated tellurophene units. On the other hand, the emission spectra suffer marked extinction owing to a heavy atom effect of tellurium, and only the extended tertellurophene shows weak fluorescence in the visible region. The elevation of the HOMO levels of the tellurophenes is suggested by low oxidation potentials in the cyclic voltammograms. Consequently, ready electrolytic and chemical oxidative coupling reactions are liable to occur to give filmy or powdered polytellurophenes, whose conductivities are wide- ranging with the order of 10-3-10-9 S cm-1, depending on the original tellurophene species and the polymerization conditions.
- Inoue, Shinobu,Jigami, Tetsuya,Nozoe, Hiroshi,Aso, Yoshio,Ogura, Fumio,Otsubo, Tetsuo
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p. 159 - 170
(2007/10/03)
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