Instigating the Anticancer Activity of New Pyridine-Thiazole-Based Co(III), Mn(II), and Ni(II) Complexes: Synthesis, Structure, DFT, Docking, and MD Simulation Studies.

The perchlorate salt of (4-(4-methoxy phenyl)-2-(2-(1-pyridine-2-yl)ethylidene)hydrazinyl)thiazole () and its metal perchlorate derivatives, namely, [Co()]ClO (), [Mn()](ClO) (), and [Ni()](ClO) (), have been synthesized and characterized through single X-ray crystallography and spectroscopic methods. The ligand crystallizes in a space group 2/ in a nearly planar structure. The overall geometry of the complex salts is described as a distorted octahedron with a MN chromophore. The ligand ( behaves as a neutral ,,-tridentate donor toward the "soft" Mn(II) and Ni(II) centers, whereas the deprotonated ligand stabilizes the "hard" Co(III) center. The DNA binding constant () values of , , , and are determined using the UV-vis spectroscopic method, and the values are 9.29 × 10, 7.11 × 10, 8.71 × 10, and 7.82 × 10 mol, respectively, indicating the intercalative mode of interactions with CT-DNA. All the derivatives show effective antiproliferative activity against U-937 human monocytic tumor cells with IC values 4.374 ± 0.02, 5.583 ± 0.12, 0.3976 ± 0.05, and 11.63 ± 0.01 μM for , , , and , respectively. The best apoptosis mode of cell death is shown by followed by and at an equivalent concentration of IC values. The combined molecular docking and dynamics simulation study evaluates the binding energies of anticancer agents, providing groove binding property with DNA. The 20 ns molecular dynamics simulation study reveals the maximum DNA binding stability of corroborating the experimental results. The new class of metal derivatives of pyridine-thiazole can be used for advanced cancer therapeutics.