Co-solvent effects on the redox potentials of manganese-substituted a-Keggin-type silicon polyoxotungstate k6siw11o39mn(h2o): First electrochemical generation of the manganese(v) redox system in an aqueous environment

Abstract

In the electrochemistry of the manganese-substituted α-Keggin silicon tungstate [K6SiW11O39Mn(II)(H2O)] in phosphate buffer, co-solvents influence the redox potential of the manganese incorporated in the heteropolyanion. Thus, the redox potentials of SiW11O39Mn(III/II)(H2O) and SiW11O39 Mn[(IV)(OH)/(III) (H2O)] shift to more negative potentials on increasing the amount of organic co-solvents. The organic solvents stabilize the more highly oxidized complex. By use of this stabilization, the generation of the pentavalent manganese-substituted silicon polyoxotungstate could be detected electrochemically for the first time.