A VOLTAMMETRIC STUDY ON THE ONE-ELECTRON REDOX PROCESSES OF THE DAWSON-TYPE HETEROPOLYMOLYBDATE COMPLEXES

The electrochemical behaviors of the Dawson-type heteropolymolybdate anions, [S2Mo18O62]4-, [P2Mo18O62]6-, and [As2Mo18O62]6- were investigated at the glassy carbon (GC) electrode. In CH3CN where no protonation accompanies reduction, the voltammogram of the [S2Mo18O62]4- anion consists of four one-electron redox waves followed by an ill-defined wave while the [P2Mo18O62]6- and [As2Mo18O62]6- anions exhibit two one-electron redox waves; the one-electron waves are reversible and diffusion-controlled. The Dawson anions undergo successive two-electron reductions under the conditions where protonation can accompany reduction. The effect of the presence of acid on the voltammetric behaviors has also been discussed.