Reaction of a satirically hindered iron(III) porphyrin with peroxyacetic acid: Degradation kinetics

A kinetic analysis of the reaction between peracetic acid (AcOOH), and tetrakis (pentafluorophenyl) - 21H, 23H-porphine iron(III) chloride, Fe(F 2 0 TPP)Cl, in acetonitrile showed that the peracetic acid oxidatively destroys Fe(F 2 0 TPP)Cl. This is in contrast to an assumption that the oxidative degradation of metallo-porphyrins can be prevented by the introduction of electron-withdrawing substituents into the phenyl groups of the porphyrin ligand. A UV-visible spectroscopic study showed a degree of macro cycle destruction of the tetrapyrrole conjucation of the metalloporphyrin. The degradation takes place via oxoperferryl species. The first step of the reaction mechanism is the reversible formation of an adduct 'X' (k 1 /k - 1 ) between Fe(F 2 0 TPP)Cl and peracetic acid, followed by an irreversible step (k 2 ) for the formation of oxoperferryl species.