Finding a new pathway for acid-induced nitrite reduction reaction: formation of nitric oxide with hydrogen peroxide.

Here, we report a new pathway for nitrite reduction chemistry, formation of cobalt-nitrosyl ({CoII-NO}8) with H2O2 in the reaction of a CoII-nitrito complex with a one-fold acid (H+) via the formation of a CoII-nitrous acid intermediate ({CoII-ONOH}). Mechanistic investigations using 15N-labeled-15NO2- revealed that the N-atom in the {CoII-NO}8 complex is derived from the nitrito ligand, and H2O2 came from the homolysis of the ON-OH moiety. Spectral evidence supporting the formation of the CoII-ONOH intermediate and the generation of H2O2 is also presented.