Different oxidation mechanisms of Mn^II(polyphosphate)_n by the radicals and

The kinetics and mechanisms of the oxidation of (Formula presented.) and of (Formula presented.) by the biological relevant radicals (Formula presented.) and (Formula presented.) were studied. The rate constants of the oxidations by both radicals are faster for the (Formula presented.) complexes than for the (Formula presented.) complexes, though the redox potentials predict the reverse order of reactivity. Surprisingly, the results point out that these two radicals react via different mechanisms. Thus, the increase in the concentration of the ligands decreases the rate constants of the oxidations by (Formula presented.) , whereas it increases the rate constants of the oxidation by (Formula presented.). These results point out that these radicals behave differently though both are inner-sphere oxidants. The plausible mechanisms of reaction of these radicals are discussed.