Exploring the nitric oxide dioxygenation (NOD) reactions of manganese-peroxo complexes

Here, we report the nitric oxide dioxygenation (NOD) reactions of two Mn-III-peroxo (M-III-O-2(2-)) complexes, [(3PYENMe)Mn-III(O-2(2-))](+) (1) and [(N3PY)Mn-III(O-2(2-))](+) (2), bearing pentadentate ligands. Complexes 1 and 2 give Mn-II-nitrate (Mn-II-NO3-) complexes (3 and 4) when reacted with nitric oxide (NO), respectively. The mechanistic study explored by using 2,4-di-tert-butylphenol (2,4-DTBP) suggested that the NOD reaction of 1 and 2 occurs via a presumed Mn-peroxynitrite ([Mn-PN](+), [Mn-ONOO-](+)) intermediate. Tracking the source of N atoms using (NO)-N-15 revealed that the N-atoms in Mn-II-NO3- (3 and 4) are derived from the (NO)-N-15 moiety. Furthermore, we have explored the M-III-O-2(2-) regeneration from NOD products (3 and 4), and we have observed the formation of M-III-O-2(2-) complexes (1 and 2) upon treatment with KO2 or H2O2/triethylamine (TEA), respectively.