Dissociation and Dioxygen Formation in Hydroxide Solutions of Tris (2,2- bipyridyl) Iron (III) and Tris (1,10-phenanthroline) Iron (III): Rates and Stoichiometry

The fast redox reactions of the title Fe(II1) complexes in basic solutions give the Fe(I1) complexes and coordinated ligand N-oxide as primary products. Further reactions by parallel paths include dissociation to give the free ligand N-oxide and catalysis by hydroxy Fe(II1) complexes leading to dioxygen. No O2 is produced when dissociation of tns(2,2’-bipyridyl)iron(III) is suppressed by addition of excess ligand; the dependence of the O2 yield on the degree of dissociation of this complex can be reproduced by using the rate constants for the parallel catalyzed and uncatalyzed decay of the first product.