Investigation of the pronounced medium effects observed in the voltammetry of the highly charged lacunary anions [α-SiW11O 39]8- and [α-PW11O39] 7-

Abstract

A detailed study is reported of the influence of protons, metal cations, and media on the redox chemistry of lacunary anions [α-SiW 11O39]8- and [α-PW11O 39]7- of high formal negative charge. Each anion displayed a single chemically reversible one-electron reduction process in carefully dried aprotic CH3CN solution. This process was detected at very negative potentials just prior to the solvent limit. Addition of 0.3 equiv of acid gave rise to a new reduction process at considerably less negative potentials, which is attributed to formation of the protonated species [SiW 11O38(OH)]7- and [PW11O 38(OH)]6-. Voltammograms derived from simulations based on a double-square scheme are in excellent..