Metal–Metal Bonds in Chains of Three or More Metal Atoms: From Homometallic to Heterometallic Chains

Abstract

Extended metal atom chains (EMACs) have attracted attention for their unique structural and bonding features. They allow for a systematic study of metal–metal bonding in discrete, oligomeric, polymetallic one-dimensional molecules. Because of their shape and bonding patterns, these complexes are often considered potential molecular wires for molecular electronic applications. As such, the electronic structure of the simplest EMACs, i.e., those that consist of three metals linked together, the ligand systems that have been used to support EMACs, and preliminary work on the conductance of EMACs at the molecular level are discussed. New heterometallic EMACs have also been recently synthesized and are discussed here. While these molecules may be of interest in molecular electronic applications, they also serve as a testing ground for studying the nature of heterometallic electronic effects.