Valence tautomerism in cobalt complexes

Abstract

Valence tautomeric (VT) complexes have attracted considerable attention due to their potential application in molecular electronic devices. This class of complexes exhibits thermally and/or photoinduced rearrangements associated with an intermolecular electron transfer between the redox active ligand and the metal ion forming two isomers of similar energy. The nature of the electroactive ligand and the type of external stimulus (light, temperature, or pressure) are critical to the generation of the two electronic isomers. Although several VT complexes have been described in the literature, the search continues for species with required properties for practical applications. The aim of this article is to present some of the most relevant complexes thus far published, while discussing the main properties that a compound should present in order to become a candidate for the development of molecular devices.