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

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⁺.