Binuclear copper(II) complexes of tolfenamic: synthesis, crystal structure, spectroscopy and superoxide dismutase activity

The synthesis and characterization of copper(II) complexes with a potent non-steroidal anti-inflammatory drug, tolfenamic acid, Htolf, with formula [Cu(tolf) 2L] 2 (where L is H 2O or DMF, N, N-dimethylformamide) were investigated. The crystal and molecular structure of [Cu(tolf) 2(DMF)] 2 was reported. Crystallographic data are as follows: monoclinic system, space group P2 1/ n with cell constants a=9.068(2) Å, b=14.514(3) Å, c=22.826(4) Å, V=2948.9(10) Å 3 and Z=2. The crystal structure consists of binuclear, quadruply bridged neutral molecule with a Cu–Cu bond length of 2.6075(19) Å. The complex is self-assembled via C–H–π intermolecular stacking interactions. Spectroscopic and electrochemical studies were reported. The superoxide dismutase activity is measured and compared with those of superoxide dismutase enzyme, SOD, the free ligand and related copper complexes with non-steroidal anti-inflammatory drugs, NSAIDs. IC 50 value was measured by the Fridovich test (1.97±0.17 μM), which showed that [Cu(tolf) 2L] 2 is a good superoxide scavenger.