Evidence for stereospecific binding of tris(1,10-phenanthroline)-ruthenium(II) to DNA is provided by electronic dichroism

Electronic dichroism measurements on a solution of DNA and enantiomeric Ru(phen)32+(phen = 1,10-phenanthroline) have revealed that the Δ- and Λ-isomers of Ru(phen)32+ are bound to DNA stereospecifically with their three-fold symmetry axes approximately parallel and vertical to the helical axis of DNA stereospecifically with their three-fold symmetry axes approximately parallel and vertical to the helical axis of DNA, respectively.