Redox and substitution reactions of <i>trans</i>-(diaqua)(N, N'-ethylenebis(salicylideneaminato)cobalt(lll) with hexacyanoferrate(ll, lll): A proton coupled electron transfer reaction

Abstract

The electron transfer between <i>trans-</i>[Co(Salen)(OH₂)₂]⁺ (Salen N, N'-ethylenebis(salicylideneaminato) and (Fe(CN)₆]^4- involved a binuclear species, [(OH₂)Co^lll(Salen)- (NCFe^IlCN₅)]^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°C (<i>I </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.