HEXAAMINECOBALT ELECTRON-EXCHANGE REACTION

In this paper we present a theoretical study of the extraordinarily slow electron-exchange reaction Co3+(NH3)6 + Co2+(NH3)6Co2+(NH3)6 + Co3+(NH3)6. With the utilization of multiphonon theory fornonadiabatic electron-transfer reactions, ki was expressed as a product of a two-center electron-exchange term, Kif2, and a nuclear Franck-Condon factor, G. Kif 2 was evaluated by invoking the effects of spin-orbit coupling, while G was calculated by incorporating the effects of configurational changes and of frequency changes in the first coordination layer, as well as the Marcus-Levich solvent reorganizationenergy. We demonstrate that both electronic spin multiplicity restrictions and the nuclear reorganization energycontribute significantly to the retardation of the rate of this reaction. The mechanism considered herein is more efficient than the alternative reaction paths which involve thermally excited electronic states. © 1979, American Chemical Society. All rights reserved.