DNA Interactions, Antimicrobial, In Vitro Cytotoxicity, Molecular Docking, Cell Cycle Analysis, and Apoptosis Assay Efficiency of Newly Nano-Sized Tridentate Cu(II), Ni(II), Pd(II), and Pt(II) Chelates of (E)-5-Fluoro-2-(((5-(2-fluorophenyl)-furan-2-yl)methylene)amino)benzenethiol

Nano-sized tridentate transition metal(II) chelates, specifically [M(FONS)Cl] with H-FONS = ligand and M = Cu(II) (C1), Ni(II) (C2), Pd(II) (C3), and Pt(II) (C4), underwent synthesis and subsequent characterization. The HOMO–LUMO energy gaps (ΔE) were used to create theoretical models for the structure and confirmation barriers in molecular systems for the ligand (H-FONS) and metal chelates. It was found that the Cu(II), Ni(II), Pd(II), and Pt(II) chelates have lower values for HOMO–LUMO energy gaps (ΔE), indicating that they are more stable than the H-FONS 1igand.The metal formed four coordinated with the tridentate NOS donor Schiff base to form square-planar geometry chelates. The results of TEM, EDX, AFM, and x-ray diffraction calculations for the bivalent metal chelates indicated sharp and intense diffraction peaks, confirming their crystalline nature and nanoscale particle size. The interaction between calf thymus DNA (CT-DNA) and the chelates was examined utilizing the UV–Vis spectroscopic method, revealing their capacity to bind with CT-DNA via intercalation mode. Nano-sized metal(II) chelates show a higher viscous nature than H-FONS. The cytotoxicity of H-FONS and its metal(II) chelates in nano form against the liver cancer cell line (HepG2) was evaluated by studying in vitro cell proliferation using the MTT assay. The findings demonstrated that all compounds exhibited anticancer properties, displaying a dose-dependent response. Our flow cytometry data indicate significant levels of cell cycle arrest in the liver cancer cell line. By molecular docking study, it was found that the Cu(II) chelate (C1) showed the highest and better binding affinity (−8.2 and −8.7 kcal/mol) than other 1igand (H-FONS) and comp1exes (C2–C4) for the BCL2 and PBP3 proteins central activities.