Electrochemical study of the nitroxyl radical derivatives built in the π-conjugated poly(phenylenevinylene) skeleton

The electrochemical oxidation and reduction of the stable neutral nitroxyl radical gave the oxoaminium salt and hydroxylamine or nitroxyl anion, respectively. The electrochemical behavior of the N-butylnitroxyl radicals or N-butylhydroxylamines built in to various phenylenevinylene species were discussed in connection with its developed π-conjugated structure based on cyclic voltammetric measurements. The aromatic nitroxyl radical showed two pairs of oxidation-reduction waves, but the acidic proton (hydroxylamine) changed its cathodic peak to a broad one with a shift to the anodic side. The π-conjugated poly(phenylenevinylene) backbone and mobile proton of the hydroxylamine unstabilized the nitroxyl radical by retaining the energy gap.