Optical Ligand to Ligand Charge Transfer of Metall Complexes Including Ligand-Based Mixed-Valence Systems

Abstract

The electronic spectra of metal complexes which contain a reducing and an oxidizing ligand (L^a-M-L*,) are characterized by ligand to ligand charge transfer (LLCT) absorptions. A specific form of Lred-M-LOJIcomplexes are ligand-based mixed-valence (LBMV) compounds which contain the same ligand in two different redox states. In this case the ligand—ligand interaction may lead to a partial or even complete electronic &localization between the reduced and oxidized form ol the ligands. As a consequence* the “LLCT’ transition loses its CT character since it takes place between delocalized orbitals. © 1990, Taylor & Francis Group, LLC. All rights reserved.