The present investigation has been aimed to prepare and characterize, several cupper complexes containing [Cu(dafone)2(H2O)2]Cl (1), [Cu(dafone)2(en)]Cl2 (2) and [Cu(dafone)2(opd)]Cl2 (3) using FT-IR, UV–Vis techniques and elemental analysis. To understand the interaction of Cu(II) compounds with FS-DNA, different spectral methods have been employed. The binding constant (Kb) was determined by UV–Vis spectroscopy. The effective binding ability of metal compounds to DNA has been proved by the obtained results. The data related to fluorescence were achieved with the purpose of evaluating the binding and thermodynamic interaction parameters of copper (II) compounds with FS-DNA, at three various temperatures. According to the thermodynamic factors (∆S°, ∆H°, ∆G°), the major interaction concerning DNA- Cu(II) complexes are hydrogen bonding and van der Waals forces. Additionally, the binding constant (Kb) and the Stern–Volmer quenching constant (Ksv) of synthesized compounds and DNA were estimated. Measuring specific viscosity of FS-DNA showed no alterations considerably, whereas the concentration of copper(II) complexes enhanced. The groove binding mode is advocated by the viscosity data and circular dichroism. The synthesized compounds were further investigated against cancerous A549 (human lung adenocarcinoma), oral squamous carcinoma C152 (KB) cell lines and normal human umbilical vein endothelial (HUVEC) cells. Compounds 1 and 2 showed a good cytotoxicity activity against cancer cell lines while the IC50 values for normal cell line was about three times higher. The interaction mode of target compounds in DNA active site was investigated and confirmed the groove binding.
