Stereochemical effects on intervalence charge transfer

Recent work has revealed the first observation of stereochemical effects on intervalence charge transfer (IVCT) in di- and trinuclear mixed-valence complexes. The differential IVCT characteristics of the diastereoisomers of polypyridyl complexes of ruthenium and osmium offer a new and intimate probe of the fundamental factors that govern the extent of electronic delocalization and the barrier to electron transfer. These findings challenge prior assertions that the inherent stereochemical identity of such complexes would have no influence on the intramolecular electron-transfer properties of polymetallic assemblies. This article provides a brief review of the past 40 years of mixed-valence research and looks at recent progress in stereochemical effects on IVCT. The implications of the findings are considered within the context of the existing theoretical and experimental framework for IVCT.