Newly developed palladium complexes featuring ONS donor ligands: synthetic method, characterization, CT-DNA interaction analysis, BSA protein binding study and in vitro cytotoxicity

Abstract

Two new palladium(II) complexes (C1 and C2) were synthesized using imine- and azo-functional ligands, namely, (E)-4-hydroxy-3-(1-((2-(methylthio)phenyl)imino)ethyl)-2H-chromen-2-one (HL¹) and (E)-6-((2-(ethylthio)phenyl)diazenyl)-7-hydroxy-4-methyl-2H-chromen-2-one (HL²). The ligands and their corresponding complexes were comprehensively characterized by NMR, IR, mass spectrometry, and UV-Vis spectroscopy. The molecular structures of the complexes were confirmed using single-crystal X-ray diffraction study. Both complexes exhibited strong interactions with CT-DNA and BSA, demonstrating high binding affinity as confirmed by UV-Vis and fluorescence spectroscopy. Furthermore, the in vitro cytotoxic activity of the complexes was tested on MCF-7 (human breast epithelial adenocarcinoma) and MCF-10A (human breast epithelial) cell lines using clonogenic and nuclear fragmentation assays. Both complexes showed potent anti-proliferative activities, with C2 displaying slightly higher potency than C1.