ELECTROCHEMICAL STUDY OF THE TRANSFER OF UNCOUPLERS ACROSS THE ORGANIC AQUEOUS INTERFACE

Ion-transfer electrochemistry at the polarizable nitrobenzene/water interface of four uncouplers of oxidative phosphorylation: picric acid, 2,4-dinitrophenol, carbonylcyanide p-trifluoromethoxyphenyl-hydrazine (FCCP), and 3,5-di(tert-butyl)-4-hydroxybenzylidenemalononitril (SF6847) is studied using potential step chronoamperometry (normal pulse voltammetry) and cyclic voltammetry. The voltammograms are interpreted in terms of the facilitated transfer of protons from the water to the nitrobenzene phase by the dissociated form the uncouplers present in the nitrobenzene phase for all the four compounds and of the simple transfer of the dissociated forms from the nitrobenzene to water phase for the first two compounds, depending on the pH of the water phase. Some physicochemical properties of the uncouplers relevant to the facilitated transfer of protons at the interface between organic and aqueous phases are presented.