Electrochemical synthesis and structural and physical characterization of one- and two-electron-reduced forms of [SMo12O40]2-

Abstract

Isolation of a soluble [NHex4]+ salt has allowed a detailed electrochemical study of the anion α-[SMo12O40]2- to be undertaken. Four reversible one-electron-reduction processes are observed in CH2Cl2 solution. Controlled potential electrolysis led to isolation of tetraalkylammonium salts of the one-electron-reduced anion α-[SMo12O40]3- and the two-electron-reduced anion α-[SMo12O40].4- [SMo12040]3- is stable to disproportionation in dry solvents (Kdis = 10-7.4). EPR and magnetic susceptibility data indicate that [SMo12O40]3- is a simple paramagnet (S = 1/2) while [SMo12O40]4- is paramagnetic with the μeff values decreasing at low temperatures. Solutions of the two-electron-reduced species ar..