Synthetic procedure for various selenium-containing electron donors of the bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) type.
Six selenium variants of BEDT-TTF have been successfully synthesized by a newly developed synthetic method that involves a combination of two key reactions for the construction of two kinds of heterocyclic rings: the first is a one-pot formation of 1,3-dichalcogenole-2-chalcogenones from a common starting material, THP-protected 2-(ethynylthio)ethanol, leading to the inner five-membered rings, and the other is the annelation of the outer six-membered heterocyclic ring onto the inner ring by an intramolecular transalkylation reaction on a chalcogen atom. This method turned out to be widely applicable to the syntheses of the electron donors of bis(ethylenedithio)- and bis(ethyleneselenothio)-substituted types. However, synthetic attempts to form analogous donors of the bis(ethylenediseleno)-substituted type from THP-protected 2-(ethynylseleno)ethanol were unsuccessful. This is attributable to the predominance of side-reactions via a seleniranium (episelenonium) salt over the desired six-membered ring formation by transalkylation via a seleninium salt.
Takimiya
Kazuo
K
Department of Applied Chemistry, Graduate School of Engineering, Hiroshima University, Higashi-Hiroshima 739-8527, Japan. ktakimi@hiroshima-u.ac.jp
Jigami
Tetsuya
T
Kawashima
Minoru
M
Kodani
Mie
M
Aso
Yoshio
Y
Otsubo
Tetsuo
T