Synthesis, DNA binding and photocleavage, and cellular uptake of an alkyl chain-linked dinuclear ruthenium(II) complex

•A dinuclear Ru(II) complex is newly synthesized and characterized.•The complex avidly binds to DNA through a threading bis-intercalative mode.•The complex acts as an efficient DNA photocleaver.•The complex acts as a low-cytotoxic luminescent cytoplasmic stain for HeLa cells.

A dinuclear ruthenium(II) complex [(bpy)2Ru(L1)Ru(bpy)2]Cl4 {bpy = 2,2′-bipyridine, L1 = 1,6-bis(3-(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)-9H-carbazol-9-yl)hexane} was synthesised and characterized. The calf thymus DNA (ct-DNA) binding properties of the complex were investigated by means of UV–Visible absorption and emission spectrophotometric titrations, ethidium bromide competitive binding, steady-state emission quenching with ferrocyanide, DNA viscosity measurements, and DNA thermal denaturation. The results indicated that the complex avidly binds to ct-DNA most probably through a threading bis-intercalative mode. The complex was also evidenced to act as an efficient DNA photocleaver, and an effective luminescent stain for cytoplasmic of HeLa cells with low cytotoxicity.

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