Electron transfer in mixed-valence compounds

Abstract

In mixed-valence compounds where electronic interactions between metal sites are relatively weak, Intervalence Transfer (IT) absorption bands can appear ( e.g. eqn. 1). The properties of IT absorption bands can be understood based on the early work of ▪ Hush and later theoretical developments. Perhaps most important is the information available in IT bands concerning related thermal electron trasfer processes. Experimentally, it has been possible to probe the role of molecular and solvent vibrations and of the distance between redox sites on the energy of the transition. Although a continuum model for the solvent has been successful in some cases, it is clear that specific solvent effects are important in others. In more recent work, it has been possible to explore the relationship between IT and related, excited state transitions, to calculate thermal electron transfer rate constants from the properties of IT bands, and to extend the treatment involved to both metalligand and donor-acceptor charge transfer transitions.