An investigation on catalytic nitrite reduction reaction by bioinspired CuII complexes

Catalytic nitrite reductions by CuII complexes containing anionic Me2Tp, neutral Me2Tpm, or neutral iPrTIC ligands in the presence of l-ascorbic acid, which served as an electron donor and proton source, were investigated. The results showed that auxiliary ligands are important for copper-mediated catalytic nitrite reduction. Furthermore, the electronic effects of the ligand govern the nitrite reduction efficiency, which should be considered at two control points: one is the susceptibility of the LCuI-nitrite species to protonation and the other is the susceptibility of LCuII to reduction giving LCuI. In addition, an external strong acid leads to the production of nitrous acid, which may suggest that the reactivity of nitrous acid toward the LCuI species is a third control point.