Synthesis of Ruthenium Complexes Bearing PCP-Type Pincer Ligands and Their Application to Direct Synthesis of Imines from Amines and Benzyl Alcohol

Ruthenium complexes bearing N-heterocyclic carbene- and phosphine-based PCP-type pincer ligands are synthesized and characterized by X-ray crystallography. The ruthenium–PCP complexes have catalytic activity toward direct synthesis of imines from reactions of amines and benzyl alcohol. The lifetime of the ruthenium complex bearing the PCP pincer ligand is longer than that of the ruthenium complex bearing a pyridine-based PNP-type pincer ligand.