Electrochemical reduction of 3,3′-bi(2-R-5,5-dimethyl-4-oxopyrrolinylidene)-1,1′-dioxides in water and its binary mixtures with acetonitrile

It has been shown by cyclic voltammetry for the first time for nitrons that the first step of electrochemical reduction of 3,3′-bi(2-R-5,5-dimethyl-4-oxopyrrolinylidene)-1,1′-dioxides in water and its binary mixtures with acetonitrile is a reversible one-electron process. The potentials of the first one-electron reduction peaks shift toward less negative values with an increase in the water content in the binary mixture, being in water equal to −0.14, −0.09, −0.08, and +0.19 V vs. saturated calomel electrode for dinitrons with R = Me, Ph, Bu^t, and CF₃, respectively. Such very low reduction potentials allow one to use derivatives of these dinitrons as redox-active labels in applied bioorganic electrochemistry. Dedicated to the memory of Academician N. N. Vorozhtsov on the 100th anniversary of his birth. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1227–1229, June, 2007.