Experimental and density functional theory study of oxygen reduction reaction at liquid-liquid interface by oxidovanadium(IV)-4-methyl salophen complex

Abstract

The catalytic reduction of oxygen (O2) by using oxidovanadium(IV)-4-methyl salophen (VOL) indicated that this complex can efficiently catalyze this reaction in the presence of ferrocene (Fc) as a weak electron donor at the interface between two immiscible electrolyte solutions (ITIES). The oxidovanadium complex has four positions for transferring proton at interface. Proton affinity (PA), gas phase basicity (GB), and pKa for these positions were calculated by using DFT method. Protonated complex (VOL-OH+) is as an active intermediate specie in this catalytic process. The catalytic oxygen reduction by VOL at liquid-liquid interface was also studied by density functional theory (DFT) computations in order to find the effect of structural parameters on this catalytic reaction. Theoretical studies indicated that the oxygen atom of V=O moiety is the most acidic and the best position for transferring proton and electron to the molecular oxygen. The results showed that the catalytic reaction can proceed by direct interaction between molecular oxygen and most acidic position in the structure of VOL.