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

Abstract

Three new diclofenac-based copper(II) complexes, namely tetrakis{mu-2-[2(2,6-dichloroanilino)phenyl]acetato-kappa O-2:O'}bis(methanol-kappa O)copper (II), [Cu-2 (mu-dicl)(4)(CH3OH)(2)] (1), bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-kappa O-2,O'}bis(1-vinyl-1H-imidazole-kappa N-3) copper(II), [Cu(dicl)(2)(vim)(2)] (2), and bis{2-[2-(2,6-dichloroanilino)phenyl]acetato-kappa O-2,O'} bis(1-vinyl-1H-imidazole -kappa N-3)copper (II), [Cu(dicl)(2)(im)(2)] (3) [dicl is diclofenac (C14H10Cl2NO2), vim is 1-vinylimidazole (C5H6N2) and im is imidazole (C3H4N2)], 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 did ligand exhibits a bidentate syn,syn-mu 2 coordination mode linking two copper(II) centres. Complexes 2 and 3 have mononuclear units with the general formula [Cu(dicl)(2)L-2] (L is vim or im) in which the Cu-II ions are octahedrally coordinated by two L and two did chelating ligands. The L and did ligands both occupy the trans positions of the coordination octahedron. The different coordination modes of did 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-2 (mu-dicl)(4)(CH3 OH)(2)] 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.