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

Two mononuclear copper(II) ibuprofenate adducts with imidazole or 2-methylimidazole and two binuclear copper(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 CuO2N2 chromophore. The above data for metronidazole or caffeine adducts are consistent with a binuclear structure as found for copper(II) acetate monohydrate and other copper(II) carboxylate dimers. In these complexes four carboxylate groups are bridging two copper(II) atoms, and two added bases coordinated at axial positions to form CuO4N 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 copper(II) ibuprofenate or its metronidazole or caffeine mono-adducts.