Synthesis and structural characterization of zinc(II) complexes with NSAIDs and picoline derivatives and investigation of anticancer activities

In this study, four coordination compounds were synthesized by using mefenamic acid /niflumic acid which are active drugs in the group of non-steroidal anti-inflammatory drugs (NSAIDs) and picoline derivatives (2-picoline, 3-picoline, 4-picoline). [Zn3(-mef)6(2-pic)2], [Zn3(-mef)6(4-pic)2] complexes were obtained microcrystal form whereas [Zn2(-mef)4(3-pic)2] and [Zn(nif)2(4-pic)2] complexes were obtained single crystal. Structure of complexes was identified by elemental analysis, FT-IR, thermal analysis and 1H NMR techniques. In addition, the structure of single crystal complexes was clarified with single-crystal X-ray diffraction. In [Zn2(-mef)4(3-pic)2], zinc(II) ion demonstrating a square pyramidal geometry whereas in [Zn(nif)2(4-pic)2], zinc(II) ion demonstrating a distorted tetrahedral geometry. Based on X-ray, thermal and elemental analysis data, the complexes were determined to be trinuclear, dinuclear and mononuclear. According to FT-IR data, it was determined that mefenamoto and niflumenato ligands were bound to zinc(II) ions with carboxylate oxygen atoms. The Δν values of the complexes calculated from the FT-IR data are in good agreement with the X-ray diffraction data. 1H NMR studies have shown that microcrystalline complexes are formed in a similar structure and the mef:pic ratio is 3:1. As a result of thermal analysis studies, the final decomposition product was determined as ZnO. In the biological activity studies carried out, all complexes exhibited strong cytotoxic activity on all cancer cells (A-549, HT-29, MCF-7 and MDA-MB-453) and the highest selectivity was displayed against the MDA-MB-453 cells.