Co-solvent effects on the redox potentials of manganese-substituted alpha-Keggin-type silicon polyoxotungstate K6SiW11O39Mn(H2O): First electrochemical generation of the manganese(V) redox system in an aqueous environment

In the electrochemistry of the manganese-substituted alpha-Keggin silicon t ungstate [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 amoun t of organic co-solvents. The organic solvents stabilize the more highly ox idized complex. By use of this stabilization, the generation of the pentava lent manganese-substituted silicon polyoxotungstate could be detected elect rochemically for the first time.