Epoxidation activities of mononuclear ruthenium–oxo complexes with a square planar 6,6′-bis(benzoylamino)-2,2′-bipyridine and axial ligands

Some ruthenium complexes, [RuII(babp)(dmso)(L)], with a square planar ligand, H2BABP, and axial ligands, L (L=dmso, imidazole, or pyridine derivatives), have been prepared as catalysts for oxygen-transfer reactions. The catalytic activity and selectivity of the metal–oxo species derived from these complexes and PhIO have been affected by the axial ligands L, in which active species has been interpreted in terms of contribution of both characters of Ru(V)O and Ru(IV)O·.