Structural Studies of Λ- and Δ-[Ru(phen)_2dppz]^(2+)Bound to d(GTCGAC)_2: Characterization of Enantioselective Intercalation

^1H and ^(31)P NMR have been applied in characterizing the enantioselective interactions between Λ- and Δ-[Ru(phen)_2dppz]^(2+) and the hexamer oligonucleotide d(GTCGAC)_2. Both isomers intercalate into the helix, and intermolecular NOEs place the Δ-isomer in the major groove. The NMR results indicate that Ru(phen)_2dppz^(2+) isomers bind to the DNA helix with a population of intercalative geometries and therefore extend earlier structural models based upon luminescence studies