The coordination of azepine to transition-metal complexes: A DFT analysis

DFT calculations with full geometry optimizations have been carried out on a series of real and hypothetical compounds of the CpM(C6NH7) and (CO)3M(C6NH7) (M = transition-metal) type. A rationalization of the bonding in all the known compounds and in hypothetical complexes is provided. Depending on the electron count and the nature of the metal, the azepine ligand can bind to the metal through the η1, η2, η4, η6, or η7 coordination mode.