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Electrochemical and Chemical Oxidation of Dithia-, Diselena-, Ditellura-, Selenathia-, and Tellurathiamesocycles and Stability of the Oxidized Species

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posted on 19.03.2010, 00:00 by Dennis H. Evans, Nadine E. Gruhn, Jin Jin, Bo Li, Edward Lorance, Noriko Okumura, Norma A. Macías-Ruvalcaba, Uzma I. Zakai, Shao-Zhong Zhang, Eric Block, Richard S. Glass
The diverse electrochemical and chemical oxidations of dichalcogena-mesocycles are analyzed, broadening our understanding of the chemistry of the corresponding radical cations and dications. 1,5-Diselenocane and 1,5-ditellurocane undergo reversible two-electron oxidation with inverted potentials analogous to 1,5-dithiocane. On the other hand, 1,5-selenathiocane and 1,5-tellurathiocane undergo one-electron oxidative dimerization. The X-ray crystal structures of the Se−Se dimer of the 1,5-selenathiocane one-electron oxidized product and the monomeric two-electron oxidized product (dication) of 1,5-tellurathiocane are reported. 1,5-Dithiocanes and 1,5-diselenocanes with group 14 atoms as ring members undergo irreversible oxidation, unlike the reversible two-electron oxidation of the corresponding silicon-containing 1,5-ditellurocanes. These results demonstrate the chemical consequences of the dication stabilities Te+−Te+ > Se+−Se+ > S+−S+, as well as Se+−Se+ > Se+−S+ and Te+−Te+ > Te+−S+.