Redox and substitution reactions of trans-(diaqua)(N,N'-ethylene-bis(salicylideneaminato)cobalt(III) with hexacyanoferrate(II,III): A proton coupled electron transfer reaction

The electron transfer between trans-[Co(Salen)(OH2)(2)](+) (Salen = N, N'-ethylene-bis(salicylideneaminato) and (Fe(CN)(6)](4-) involved a binuclear species, [(OH2)Co-III(Salen)-((NCFeCN5)-C-II)](3-), as an intermediate. The kinetics of the formation of this binuclear species and the one formed by the reaction of the title complex with [FeCN6](3-) have been studied at 20-35 degrees C (I = 0.5 mol dm(-3)); the data are consistent with the I-d mechanism. Both spontaneous and H+ coupled paths are identified for the electron transfer within the binuclear species of hexacyanoferrate(II) which further undergoes electron transfer with [FeCN6](4-) via a second order path.