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

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(2)O (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 CuN2O2+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 CuN2O2+O chromophore. The Cu-II 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 1 and 2 on the rate of hydrolysis of bis(p-nitrophenyl) phosphate (BNPP) have been examined in aqueous methanol solution at 70 degrees C and pH 7.4. Copyright (C) 1996 Elsevier Science Ltd