Crystal structure, Hirshfeld surface analysis, molecular modeling, electrochemical properties, and potential medicinal activity of a novel binuclear Co(II) complex

Abstract

A quinoxaline‐based ligand, 6,7‐dimethyl‐2,3‐di(2‐pyridyl)quinoxaline (Me 2 dpq), and its unique binuclear Co(II)‐Me 2 dpq complex were prepared and analyzed using single crystal X‐ray diffraction and several spectroscopy techniques. Hirshfeld surface analyses were also used to clarify the Me 2 dpq ligand and the Co(II)‐Me 2 dpq crystal packing. The Co(II)‐Me 2 dpq complex crystallized in triclinic P‐1 space group and exhibited a distorted trigonal bipyramidal geometry around the cobalt(II) ion. Each Co(II) ion coordinated to a Me 2 dpq ligand through two N donor centers from pyridyl and quinoxaline rings along with a terminal Cl and two bridged Cl atoms. The binding properties of the ligand and its complex with CT‐DNA were studied by several techniques, namely UV–Vis spectroscopy, fluorescence quenching, viscosity measurements, thermal denaturation, and gel electrophoresis. The CT‐DNA binding interaction tests demonstrated that both the Co(II)‐Me 2 dpq complex and its parent ligand bind to DNA in an intercalative way. The antioxidant studies of the novel Co(II)‐Me 2 dpq complex illustrated significant activity against DPPH • and radicals. The in vitro cytotoxic effect of Me 2 dpq ligand and its Co(II)‐complex on MCF‐7 and Hep‐G2 tumor cell lines was evaluated by using the MTT assay. The studies showed that the Co(II)‐Me 2 dpq complex had superior activity toward the tested cell lines. Molecular docking studies of synthesized compounds were employed to figure out the way they would associate with a biologically macromolecular target B‐DNA (PDB: 1BNA). Thus, this study is anticipated to provide novel opportunities for the successful utilization of the synthesized compounds in many medical domains.