Synthesis and characterization of copper-ibuprofenate complexes with 2, 2′-bipyridine and 1, 10-phenanthrolines and their hydrolytic activities in phosphate diester cleavage

Abstract

A synthetic investigation of copper (II) ibuprofenate (Ibup) addition compounds with 2, 2′-bipyridine (bpy), 1, 10-phenanthroline (phen) and 2, 9-dimethyl-1, 10-phenanthroline (dmph) has led to the isolation of dinuclear adducts of the forms [Cu(Ibup) 2(bpy)] 2·4H 2O ( 1) and [Cu(Ibup) 2(phen)] 2 ( 2) and a mononuclear adduct Cu(Ibup) 2(dmph) ( 3). Spectroscopic data for adducts 1 and 2 are consistent with a dinuclear structure with two CuN 2O 2+O chromophors. Each copper is coordinated with two ibuprofenate bridges, a terminal diimine molecule and a monodentate ibuprofenate group complete five-coordination at each metal atom. Spectroscopic data for adduct 3 are consistent with a mononuclear structure having a very distorted square-pyramidal CuN 2O 2+O chromophore. The Cu II atom is coordinated to two nitrogen atoms from a chelating dmph ligand, two car☐ylic oxygens of a bidentate ibuprofenate ion and an oxygen atom of a monodentate car☐ylic group of a second ibuprofenate ion. The reduction of adduct ( 3) by ascorbic acid produced stable red copper(I) complex of the form [Cu(dmph) 2] (Ibup) ( 4). Spectral data of this adduct indicated that the cation has distorted tetrahedral geometry about the copper atom. The effect of 1 and 2 on the rate of hydrolysis of bis( p-nitrophenyl) phosphate (BNPP) have been examined in aqueous methanol solution at 70°C and pH 7.4.