Enhancing oxygen reduction through proton transfer: Exploring the catalytic role of ajoene as a proton facilitator

Abstract

The study of the oxygen (O₂) reduction reaction and its underlying mechanisms in the presence of various catalysts is a topic of significant interest for both electrochemists and biochemists, particularly in the context of energy conversion. This theoretical investigation primarily focuses on the protonation of O₂ by the conjugate acids of ajoene ligand. Additionally, it aims to explore the reduction of activated O₂ by weak electron donors, such as ferrocene, at the water/dichloromethane interface. The calculations conducted in this study employ Density Functional Theory (DFT) at the B3LYP level, utilizing the 6-31G, 6-31G*, 6–31 + G* and 6-311G* basis sets in gas and solution state, as well as DFT/M06/6-31G* and Møller-Plesset perturbation theory (MP2) with the 6-31G* basis set. The results indicate that the catalytic reaction can proceed through the direct interaction of O₂ with the most basic conjugate acid, leading to the formation of a proton-bonded complex and an electrophilic cation-diradical.