Mechanistic studies of NO reduction reactions involving copper complexes: encouragement of DFT calculations.

The reduction of nitrogen oxides (NO), which is mainly mediated by metalloenzymes and metal complexes, is a critical process in the nitrogen cycle and environmental remediation. This Frontier article highlights the importance of density functional theory (DFT) calculations to gain mechanistic insights into nitrite (NO) and nitric oxide (NO) reduction reactions facilitated by copper complexes by focusing on two key processes: the reduction of NO to NO by a monocopper complex, with special emphasis on the concerted proton-electron transfer, and the reduction of NO to NO by a dicopper complex, which involves N-N bond formation, NO isomerization, and N-O bond cleavage. These findings underscore the utility of DFT calculations in unraveling complicated reaction mechanisms and offer a foundation for future research aimed at improving the reactivity of transition metal complexes in NO reduction reactions.