Synthesis, crystal structures and characterizations of three new copper(II) complexes including anti-inflammatory diclofenac.

Three new diclofenac-based copper(II) complexes, namely tetrakis{μ-2-[2-(2,6-dichloroanilino)phenyl]acetato-κO:O'}bis(methanol-κO)copper(II), [Cu(μ-dicl)(CHOH)] (1), bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κO,O'}bis(1-vinyl-1H-imidazole-κN)copper(II), [Cu(dicl)(vim)] (2), and bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-κO,O'}bis(1H-imidazole-κN)copper(II), [Cu(dicl)(im)] (3) [dicl is diclofenac (CHClNO), vim is 1-vinylimidazole (CHN) and im is imidazole (CHN)], have been synthesized and characterized by elemental analysis, FT-IR spectroscopy, thermal analysis and single-crystal X-ray diffraction. X-ray diffraction analysis shows that complex 1 consists of dimeric units in which the dicl ligand exhibits a bidentate syn,syn-μ coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)L] (L is vim or im) in which the Cu ions are octahedrally coordinated by two L and two dicl chelating ligands. The L and dicl ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of dicl in the title complexes were revealed by Fourier transform IR (FT-IR) spectroscopy. The spin matching between the copper(II) centres in the dimeric [Cu(μ-dicl)(CHOH)] units was also confirmed by magnetic data to be lower than the spin-only value and electron paramagnetic resonance (EPR) spectra. The thermal properties of the complexes were investigated by thermogravimetric (TG) and differential thermal analysis (DTA) techniques.