Abstract: | Qualitative 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. |