Synthesis and investigation of in vitro cytotoxic activities and thermal stability of novel pyridine derivative platinum (II) complexes vis a vis DFT studies

[Display omitted] Bis(2-amino-5-nitropyridine)dichloroplatinum(II), [PtCl2L12] and bis(3,4-dimethylpyridine)dichloroplatinum(II), [PtCl2L22] complexes were synthesized and characterized via FT-IR, UV–Vis, 1H NMR, 13C NMR spectrometers. Single crystal X-ray diffraction measurements were conducted to determine the crystal structure of the [PtCl2L22] complex. The [PtCl2L22] was crystallized in the monoclinic crystal system with P21/c space group. The crystal parameters were Z = 2, a = 9.5881(5) Å, b = 12.5863(7) Å and c = 13.5363(7) Å. Experimental data are supported by the theoretical calculations. LanL2DZ based DFT/B3LYP method was used determine the molecular structures of the complexes for their probable most stable status. Potential energy distribution analysis was made for to confer the vibrational transitions for the complexes. Molecular electrostatic potential maps, frontier molecular orbitals and Mulliken charge distribution were calculated and the active regions of the molecules were determined. In this study, for to investigate the interaction mechanisms of [PtCl2L12] and [PtCl2L22] complexes with colon cancer protein molecular docking study was performed. The thermal analyses of the complexes were carried out via DTA/TGA/TG combined system. The activation energies of the complexes were calculated to be 134.31–175.40 kJ/mol via Flynn-Wall-Ozawa (FWO) and 132.42–179.41 kJ/mol via Kissenger-Akahira-Sunose (KAS) methods. The cytotoxic effects of the complexes against the colon cancer cell line (DLD-1) were investigated. The complexes were found to be cytotoxic against DLD-1 colon cancer cell lines, A549 human lung cancer cells and Beas-2Bhealthy human lung epithelial cells. The results indicate that the [PtCl2L12] complex, in which amino and nitro groups are bound as ligand on the pyridine ring, have higher cytotoxic effect.