Physico-Chemical and Catalytic Studies on Complexation Behaviour of Polystyrene-1,10-phenanthrolino-5,6-bis-4',5-dihydroxyimino-7-methoxy Isoflavone with Some Transition Metals

Abstract

A novel polymeric ligand (PS-PDMI) has been synthesized from the reaction of 5,6-diamino-1,10-phenanthroline with 4',5-dihydroxy-7-methoxy isoflavone and then polymerized with chloromethylated polystyrene unit. Metal complexes of 3d (VO²⁺, Cr³⁺), 4d (Mo⁶⁺, Ru³⁺, Rh⁴⁺) and 5d (Os³⁺, Ir⁴⁺) series were prepared and characterized by elemental, spectroscopic, conductance and magnetic techniques. Coordination was found to be through the nitrogen (C=N), oxygen (O-H) and oxygen (lactone) in an octahedral environment. Ru(III)-chelate was found to be an effective catalyst for the oxidation of benzyl alcohol and cyclohexanol to benzaldehyde and cyclohexanone, respectively in the presence of co-oxidant N-methyl morpholine- N-oxide (NMO). Protonation constants of the ligand and the overall formation constants of the complexes have also been calculated from potentiometric data using the program TITFIT.