Synthesis, characterization and DNA-binding studies of chiral ruthenium(II) complexes with 2-(5-nitrofuran-2-yl)-1 H-imidazo[4,5- f][1,10]phenanthroline

Two new chiral ruthenium(II) complexes Δ-[Ru(bpy) ₂(nfip)] ²⁺ and Λ-[Ru(bpy) ₂(nfip)] ²⁺ (in which bpy = 2,2'-bipyridine, nfip = 2-(5-nitrofuran-2-yl)-1 H-imidazo[4,5- f][1,10]phenanthroline) have been synthesized and characterized by elemental analysis, ES-MS, ¹H NMR and CD spectra. The binding properties of two chiral complexes with calf thymus DNA have been investigated by different spectrophotometric methods and viscosity measurements. A subtle but detectable difference was observed in the interaction of both enantiomer with CT-DNA, Δ enantiomer binds with DNA more strongly than Λ enantiomer. Viscosity experiments provided evidence that both Δ-[Ru(bpy) ₂(nfip)] ²⁺ and Λ-[Ru(bpy) ₂(nfip)] ²⁺ bound to DNA by intercalation.