Synthesis and Catalytic Applications of Ru and Ir Complexes Containing N,O-Chelating Ligand

Abstract A series of monometallic complexes (Ru1-3, Ir1-3) which have N,O-chelating ligand (pyrazine-2-carboxylate (1), pyridine-2-carboxylate (2), quinoline carboxylate(3) and bimetallic complexes (Ru4,5, Ir4,5) bridged by pyrazine-2,3- dicarboxylate (4) and imidazole-4,5-dicarboxylate(5) were synthesized and characterized by 1H-, 13C-NMR, FT-IR, and elemental analysis. The crystal structure of Ir2 was determined by X-ray crystallography. The complexes (Ru1-5, Ir1-5) were applied to investigate the electronic and steric effect of ligand in their catalytic activities in transfer hydrogenation and alpha(α)-alkylation reaction of ketones with alcohols. The activities of iridium complexes (Ir1-5) were much more efficient than ruthenium complexes (Ru1-5). The highest activity for both reactions was observed for the complex (Ir2) with pyridine-2-carboxylate. The Ir hydride species was monitored for both reactions.