Benzyl viologen cation radical: First example of a perfectly selective anion ionophore of the carrier type

Abstract

Measurements were made of the effect of dicationic (oxidized) and monocationic radical (reduced) forms of benzyl viologen (BV) and methyl viologen (MV) on the ion conductance across planar phospholipid bilayers under conditions of constant voltage. BV + at 60 μM greatly increased ion conductance whereas BV 2+, MV + and MV 2+ did not. Ion permeability ratios relative to nitrate were determined in the BV + system. BV + appears to be the first example of a perfectly anion-selective ionophore of the carrier type. BV + probably functions both as an electron carrier and ionophore for nitrate while catalyzing the dithionite-nitrate reductase reaction in Paracoccus denitrificans .