Tridentate Amido Carbene Ligands in Early-Transition-Metal Coordination Chemistry

Coordination of the new tridentate N-heterocyclic carbene ligand precursor ( p -Me-C 6 H 4 NHCH 2 CH 2 ) 2 N 2 C 3 H 2 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.