Electrooxdation of Tricarbonyl(N,N‐Diphenylcyclohexadienecarboxamide)Iron Complexes. Reversibility of Electron Transfer and Free Energy Change

Abstract

AbstractQualitative and quantitative criteria of irreversibility of electron transfer in cyclic voltammetry (CV) of tricarbonyl(N,N‐diphenylcyclohexadienecarboxamide)iron complexes were investigated. The measurement of the heterogeneous rate constants for electron transfer according to CV data over an extended range of free energy change ( ΔG) for these complexes are described. Kinetic analyses of the electrochemical technique demonstrates that when the applied potential exceeds the standard potential E°, the experimental rate constant ke represents an accurate measurement of the intrinsic rate constant k1 for electron transfer. However, as the applied potential is less than E°, the reversibility of the electron‐transfer process becomes increasingly more important, and the rate constants for reverse electron transfer k‐t and decomposition k2 of the electrogenerated intermediate have to be taken into account.