Novel heteroleptic ruthenium complexes incorporating 6,7-dichloro-2,3-di(pyridine-2-yl)quinoxaline as polypyridyl bridging ligand: Synthesis, characterization, photophysical, electrochemistry, in vitro biological activity and molecular docking studies

•Synthesis of novel mononuclear and homodinuclear Ru(II) complexes.•Synthesis of novel mixed trinuclear Ru(II)/Ru(III) complex.•Sstructures elucidateion the by UV-Vis, Near InfraRed spectroscopy, NMR, ESI-Mass and cyclic voltammetry techniques.•Investigating phrancological performance of the complexes.•Performing molecular docking studies on the DNA-interaction with the complexs. Three new heteroleptic ruthenium(II) complexes with mixed ligands were prepared: [Ru(bpy)2(Cl2dpq)]Cl2 (1), [Ru(bpy)2(Cl2dpq)Ru(bpy)2]Cl4 (2), and [Ru(bpy)2(Cl2dpq)RuCl2(Cl2dpq)Ru(bpy)2]Cl5 (3), in which Cl2dpq = 6,7-dichloro-2,3-di(pyridin-2-yl)quinoxaline; bpy = 2,2′-bipyridine. Various physicochemical tools were used to characterize the new complexes, such as elemental analysis, infrared, 1H-NMR and ESI-MS. The complexes were investigated for their Photochemical properties by studying their UV-Vis, luminescence, and NIR spectra. Additionally, cyclic voltammetry studies were performed to evaluate the electrochemical behavior of the complexes. Investigation of the new complexes’ interaction with calf thymus DNA (CT-DNA) was carried out using various spectroscopic techniques and the experimental data were corroborated against molecular docking studies. Furthermore, the complexes' in vitro cytotoxicity against DPPH radicals and their scavenging effects against HeLa and MCF-7 cell lines were assessed. [Display omitted]