Tridentate amido carbene ligands in early-transition-metal coordination chemistry

Coordination of the new tridentate N-heterocyclic carbene ligand precursor (p-Me-C6H4NHCH2-CH2)(2)N2C3H2 to Zr(IV) generates an [NCN] donor set where the N represents an amido unit and the C corresponds to the N-heterocyclic carbene. This ancillary ligand allows for the isolation and structural characterization of zirconium amido, chloro, and alkyl derivatives; the carbene donor is rendered stable to dissociation because of its central disposition between two anionic amido units.