SNS pincer type Pd(II), Ni(II), and Fe(II) complexes: Synthesis, structural characterization, cytotoxic activity studies, molecular docking and simulation studies

Abstract

A novel SNS pincer-type ligand, 2,6-bis[[(2-chlorophenyl)thio]carbonyl]pyridine (L), along with its metal complexes (L-Ni, L-Pd, L-Fe), were synthesized and examined through a variety of analytical techniques, including X-ray crystallography (for the ligand), NMR spectroscopy, UV–Vis spectroscopy, FT-IR spectroscopy, molar conductivity, and elemental analysis methods. X-ray single crystal structure determination was employed to characterize the molecular structure of ligand (L). A four-coordinated square planar shape characterizes the Pd complex, in contrast to the five-coordinate distorted trigonal bipyramidal geometry seen in the molecular structures of Fe and Ni complexes around their metal centers. The L-Pd pincer complex is bidentate, while the L-Fe, and L-Ni pincer complexes are tridentate. Within the scope of this study, the synthesized ligand and its palladium, nickel, and iron complexes were tested against two different human cancer cell lines for 48 and 96 h. According to the results obtained, the nickel and iron complex together with the ligand has a cytotoxic effect against both cancer cell lines tested. Consequently, the nickel complex (L-Ni) was identified as the most effective compound on the lung cancer cell line in the experiments. The binding potential of the synthesized compounds to 3Dpol was explored through molecular modeling as some compounds with similar scaffolds were reported to be inhibitors of this target. The docking study disclosed that the compounds could bind to the 3Dpol structure. The molecular dynamics (MD) simulation study disclosed that compound L formed a stable complex with the target structure and could remain inside its binding site during the simulation time. © 2025 Elsevier B.V., All rights reserved.