New zinc(II) complexes of the Non-steroidal Anti-Inflammatory Drug (indomethacin) and various nitrogen donor ligands. Synthesis, characterization and biological activity

A series of complexes of Zn(II), [Zn-2(Indo)(4)] 1, [Zn-2(indo)(4)(pico)(2)] 2, [Zn(indo)(2)(apy)(2)] 3, [Zn(indo)(2) (ampy)] 4, [Zn(indo)(2)(phen)] 5, [Zn(indo)(2)(dmph)] 6, [Zn(indo)(2)(admp)(2)] 7, (indo = indomethacin, apy = 2-amino pyridine, dmph = 2,9-dimethyl-1,10-phenanthroline, pico = 3-picoline, ampy = 2-amino-methyl pyridine, phen = 1,10-phenanthroline, admp = 2-amino-4,6-dimethylpyrimidine) were synthesized and characterized using IR, UV-Vis, (HNMR)-H-1, C-13{H-1}NMR spectroscopic techniques in order to examine their binding coordination modes in addition to their biological activity. The crystal structures of complex 2 was determined by single crystal X-ray diffraction, showing binuclear complex with two 3-picoline groups one for each Zn(II) center, and four indomethacin molecules, two of them were bidentate chelating, one was bidentate bridging, and the other was monodentate terminal bridging. In-vitro anti-bacterial activities of the complexes were screened using agar diffusion method against two gram-positive bacteria (Staphylococcus aureus, Listeria monocytogenes) and two gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa). Most of the complexes showed anti-bacterial effects against P. aeruginosa, and S. aureus while they were inactive toward E. coli and L monocytogenes. Complexes 1-4 showed higher activity upon complexation against P. aeruginosa and S. aureus than their parent ligands. Complex 5 showed decreased activities upon complexation against all tested bacteria except against P. aeruginosa were it was inactive. Complex 6 showed decreased activity against S. aureus, but its activity was not affected by complexation against P. aeruginosa. Complex 7 showed higher activity against S. aurens, and no activity against P. aeruginosa. 2016 Elsevier Ltd. All rights reserved.