Anticancer evaluation of Co(III) complex derived from 1-isonicotinoyl-4-(4-nitrophenyl)-3-thiosemicarbazide: Structural characterization, photophysical, and Hirshfeld studies

Abstract

A new cationic complex, [Co((intph)(en)2]Cl, derived from the 1-isonicotinoyl-4-(4-nitrophenyl)-3-thiosemicarbazide (H2intph), is reported. The synthesized ligand and its corresponding Co(III) complex were successfully characterized by applying FT-IR and UV–visible spectroscopic techniques and single crystal ray diffraction data. Molecular geometries of the ligand and its Co(III) complex were accurately determined from their respective X-ray crystallographic analysis. The ligand and [Co((intph)(en)2]Cl crystallize in Triclinic and monoclinic systems with space groups P-1 and P 21/n, respectively. The crystal structures of H2intph and [Co((intph)(en)2]Cl are stabilized by weak C-H⋯O, N-H⋯O, and C-H⋯Cl hydrogen bonding interactions. Hirshfeld surface analysis was accomplished to investigate intermolecular hydrogen bonding interactions found in ligand H2intph and [Co((intph)(en)2]Cl. The cytotoxicity of the ligand and the complex [Co((intph)(en)2]Cl was assessed for their anticancer potential against human glioblastoma (U87) and Dalton lymphoma (DL) cell lines. The complex exhibited IC50 values of 100 μg/mL for U87 cells and 120 μg/mL for DL cells, indicating the concentration at which 50 % of cell viability was inhibited. In comparison, the ligand was less effective in the MTT assay against both U87 and DL cells. These results suggest that the complex [Co((intph)(en)2]Cl significantly reduces glioblastoma cell viability. Treatment with the complex induced cell death through both apoptotic and necrotic pathways, as evidenced by Hoechst/PI double staining. Additionally, there was an increase in intracellular reactive oxygen species (ROS), highlighting the role of oxidative stress in the anticancer activity of the [Co((intph)(en)2]Cl complex. Furthermore, fluorescence studies were carried out which revealed the order of fluorescence behaviors between the ligand and the Co(III) complex to be Co(III) complex > H2intph.