Synthesis, X-ray Structure and Biological Studies of New Self-Assembled Cu(II) Complexes Derived from s -Triazine Schiff Base Ligand.

The two ligands 2-(1-(2-(4,6-dimorpholino-1,3,5-triazin-2-yl)hydrazono)ethyl)aniline ( DMAT ) and 2-(1-(2-(4,6-dimorpholino-1,3,5-triazin-2-yl)hydrazono)ethyl)phenol ( DMOHT ) were used to synthesize three heteroleptic Cu(II) complexes via a self-assembly technique. The structure of the newly synthesized complexes was characterized using elemental analysis, FTIR and X-ray photoelectron spectroscopy (XPS) to be [Cu(DMAT)(H 2 O)(NO 3 )]NO 3 .C 2 H 5 OH ( 1 ), [Cu(DMOT)(CH 3 COO)] ( 2 ) and [Cu(DMOT)(NO 3 )] ( 3 ). X-ray single-crystal structure of complex 1 revealed a hexa-coordinated Cu(II) ion with one DMAT as a neutral tridentate NNN -chelate, one bidentate nitrate group and one water molecule. In the case of complex 2 , the Cu(II) is tetra-coordinated with one DMOT as an anionic tridentate NNO -chelate and one monodentate acetate group. The antimicrobial, antioxidant and anticancer activities of the studied compounds were examined. Complex 1 had the best anticancer activity against the lung carcinoma A-549 cell line (IC 50 = 5.94 ± 0.58 µM) when compared to cis -platin (25.01 ±2.29 µM). The selectivity index (SI) of complex 1 was the highest (6.34) when compared with the free ligands (1.3-1.8), and complexes 2 (0.72) and 3 (2.97). The results suggested that, among those compounds studied, complex 1 is the most promising anticancer agent against the lung carcinoma A-549 cell line. In addition, complex 1 had the highest antioxidant activity (IC 50 = 13.34 ± 0.58 µg/mL) which was found to be comparable to the standard ascorbic acid (IC 50 = 10.62 ± 0.84 µg/mL). Additionally, complex 2 showedbroad-spectrum antimicrobial action against the microbes studied. The results revealed it to possess the strongest action of all the three complexes against B. subtilis . The MIC values found are 39.06, 39.06 and 78.125 μg/mL for complexes 1 - 3 , respectively.