Interaction of Λ- and Δ-[Ru(bpy)2(pbmz)](PF6)2 with the oligonucleotide duplex d(CGCGAATTCGCG)2

Synthesis, characterization, DNA-binding and spectral properties of complexes [Ru(L)4(dppz)]2+ (L=Im and MeIm)

“…Since these two Ru(II) complexes have the same intercalated ligand dppz, the obvious differences of CD signal of CT-DNA in the presence of complexes 1 and 2 should come from the effect of the different ancillary ligands. For complex 1, besides the intercalation, the H linking to N atom of the ancillary ligand imidazole, may result in hydrogenbonding with N or O atoms located on the edges of DNA base pairs [27,[58][59][60], and further result in the change in the base stacking, and thus result in the obvious changes of the CD signals. However, for complex 2, there is only intercalative binding between complex 2 and DNA, and no such a hydrogen bond effect of co-ligand exists.…”

“…Upon intercalation, the imidazole ligands could be expected to be involved in less hindrance than some polypyridyl ancillary ligands. Moreover, the H linking to N atom of co-ligand imidazole, may form hydrogen-bonding with the functional groups located on the edges of DNA to favor intercalation of the main ligand, and thus such co-ligands make DNA-binding affinity of the complex strengthen [27].…”