Catalytic efficacy of Schiff-base copper(II) complexes: Synthesis, X-ray structure and olefin oxidation

Abstract

Three copper(II) Schiff-base complexes, [Cu(L 1)(H 2O)](ClO 4) ( 1), [Cu(L 2)] ( 2) and [Cu(L 3)] ( 3) have been synthesized and characterized [where HL 1 = 1-( N- ortho-hydroxy-acetophenimine)-2-methyl-pyridine], H 2L 2 = N, N′-(2-hydroxy-propane-1,3-diyl)-bis-salicylideneimine and H 2L 3 = N, N′-(2,2-dimethyl-propane-1,3-diyl)-bis-salicylideneimine]. The structure of complex 1 has been determined by single crystal X-ray diffraction analysis. In complex 1, the copper(II) ion is coordinated to one oxygen atom and two nitrogen atoms of the tridentate Schiff-base ligand, HL 1. The fourth coordination site of the central metal ion is occupied by the oxygen atom from a water molecule. All the complexes exhibit high catalytic activity in the oxidation reactions of a variety of olefins with tert-butyl-hydroperoxide in acetonitrile. The catalytic efficacy of the copper(II) complexes towards olefin oxidation reactions has been studied in different solvent media.