Electron spray ionization mass study on dioxygenation process in the reaction of catecholatoiron(III) complexes with molecular oxygen

Dioxygenation process in the reaction of catecholatoiron(III) complexes [Fe(TPA)(Cat)]BPh4 with 18O2 was investigated by means of ESI-MS spectroscopy. The results suggest that the second oxygen atom is incorporated into muconic anhydride through the nucleophilic attack on muconic anhydride by an 18O-oxo-group of the metal center, and that this process competes with dissociation of muconic anhydride from the metal center.