Magnetic perturbation of the redox potentials of localized and delocalized mixed-valence complexes

INOR 11

Claude Lapinte, lapinte@univ-rennes1.fr, UMR 6226 "Sciences Chimiques de Rennes", CNRS - Université de Rennes 1, Campus de Beaulieu, Bat 10C, Room 134, Rennes, 35042, France
In mixed-valence complexes electron transfer between the metal centers can be induced thermally or photochemically. Evaluation of the intensity of the coupling between the metal centers can be achieved by the determination of the free energy of comproportionation, ΔGc, which corresponds to the equilibrium of comproportination. Usually, the magnitude of ΔGc can be adequately described by four factors: ΔGs, ΔGe, ΔGi, and ΔGr which represent the statistical distribution, the electrostatic repulsion, the inductive factor and the free energy of resonance exchange. In particular examples, it has also been shown that additional terms to represent the ion pairing energy or the antiferromagnetic interaction must be included. We report here that magnetic exchange interaction plays a key role in mixed-valence systems with a carbon rich bridge between the remote metal ends.