Disentangling Potential Inversion and Electron Transfer Kinetics in Two-Electron Systems Using Convolution Voltammetric Analysis

High Resolution Image Download MS PowerPoint Slide Two-electron electrochemical systems with potential inversion often yield a single voltammetric wave, obscuring the individual thermodynamic and kinetic parameters of each electron transfer step. While such systems are well described under Nernstian conditions, kinetic interference renders them intrinsically underdetermined when classical Butler–Volmer laws applies. Here, we demonstrate that deviations from linear activation–driving force relationships enable parameter extraction using convolution voltammetry. A formulation of the cyclic voltammogram for chemically reversible two-electron systems without disproportionation is proposed, and strategies are developed to determine the average standard potential of the two one-electron systems and apparent rate constants under kinetic control. By analyzing limiting cases and invoking Marcus–Hush–Levich kinetics, we show that individual standard potentials and reorganization energies can be disentangled. The methodology is validated through simulations and applied to the transition-metal complexes [Pt(dmpe) 2 ](BPh 4 ) 2 and [Rh(phen)(Cp*)Cl](Cl). In both cases, kinetic curvature reveals the rate-determining step and enables quantitative estimation of electron-transfer parameters. DFT calculations confirm that geometric changes upon reduction of both complexes are likely responsible for the observed potential inversion.