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 (lbup) addition compounds with 2,2'-bipyridine (bpy), 1,10-phenanthroline (phen) and 2,9-dimethyl-l,10-phenanthroline (dmph) has led to the isolation of dinuclear adducts of the forms [Cu(Ibup)2(bpy)]z'4H20 (1) and [Cu(Ibup)2(phen)]2 (2) and a mononuclear adduct Cu(lbup)2(dmph) (3). Spectroscopic data for adducts 1 and 2 are consistent with a dinuclear structure with two CuN202+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 CuN202+O chromophore. The Cu H atom is coordinated to two nitrogen atoms from a chelating dmph ligand, two carboxylic oxygens of a bidentate ibuprofenate ion and an oxygen atom of a monodentate carboxylic 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 I 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