Synthesis, characterization and biological activity of novel complexes of zinc(II) diclofenac with nitrogen based ligands

A series of novel complexes of Zn(II) [Zn(diclo)2(H2O)2] (1), [Zn(diclo)2(apy)2] (2), [Zn(diclo)2(dmph)]2 (3), [Zn2(diclo)4(pico)2] (4), [Zn(diclo)2(ampy)] (5), [Zn(diclo)2(phen)] (6), [Zn(diclo)2(admp)2] (7) (diclo = diclofenac, apy = 2-amino pyridine, dmph = 2,9-dimethyl-1,10-phenanthroline, pico = 3-picoline, ampy = 2-aminomethyl pyridine, phen = 1,10-phenanthroline, admp = 2-amino-4,6-dimethylpyrimidine) were synthesized and characterized using IR, UV–Vis, 1H NMR, 13C{1H} NMR spectroscopic techniques as well as single crystal X-ray diffraction were used to characterize complexes (1), (2) and (3).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, but they were inactive toward E. coli and L. monocytogenes. Complexes (1), (2), (4), (5) and (7) showed higher activity upon complexation against P. aeruginosa, and S. aureus than their parent ligands. Complex (3) showed decreased activity against S. aureus upon complexation, but their activity against P. aeruginosa was not affected. Complex (6) showed decreased activity upon complexation against all tested bacteria; except P. aeruginosa where it was inactive.

Graphical abstractThis work reports synthesis and spectroscopic characterization of mixed ligand Zn(II) complexes of diclofenac and aromatic nitrogen based ligands. The crystal structures of complexes 1, 2 and 3 were determined using single-crystal X-ray diffraction.In vitro anti-bacterial activity of the prepared complexes and their parent ligands were investigated against different Gram-positive and Gram-negative bacteria using agar diffusion method.Figure optionsDownload full-size imageDownload as PowerPoint slide