Mononuclear and binuclear copper(II) complexes of the antiinflammatory drug ibuprofen : synthesis, characterization , and catecholase-mimetic activity

Abstract

Two mononuclear coppeI(II) ibuprofenate adducts with imidazole or 2-methylimidazole and two binuclear coppeI(II) ibuprofenate adducts with metronidazole or caffeine have been prepared and characterized. Elemental analyses, UV-VIS, IR, EPR, and magnetic moment data for imidazole or 2-methylimidazole adducts are consistent with mononuclear square planar complexes that contain two ibuprofenato ligands and two N-containing imidazole ligands to give essentially a Cu02N2 chromophore. The above data for metronidazole or caffeine adducts are consistent with a binuclear structure as found for coppeI(II) acetate monohydrate and other coppeI(II) carboxylate dimers. In these complexes four carboxylate groups are bridging two coppeI(II) atoms, and two added bases coordinated at axial positions to form Cu04N chromophore around each copper. The catecholase-mimetic catalytic activities of the complexes have been determined by monitoring the formation of o-quinone from catechol. The catalytic activities of the mononuclear complexes are lower than those of the binuclear coppeI(II) ibuprofenate or its metronidazole or caffeine mono-adducts.