Shape- and enantioselective interaction of Ru(II)/Co(III) polypyridyl complexes with DNA

This paper presents recent progress in our laboratory on the interaction of Ru(II)/Co(III) polypyridine complexes with DNA. The first part describes the effect on DNA binding of modulating the intercalative ligand and the size of the ancillary ligand of the complex. DNA binding modes and binding affinity can be modulated by ligand design. The second part focuses on the enantioselective DNA binding behavior of the Ru(II) complexes using absorption spectra, emission spectra, viscosity measurements, equilibrium dialysis and CD titrations. The enantiomers of the various Ru(II) complexes show diverse enantioselectivity on binding to DNA. Different equilibrium rates were observed for the enantiomers of the complex in a time-dependent dialysis experiment. The interesting effect of the molecular switch for DNA was observed for several Ru(II) complexes. Their DNA binding properties, together with the possible mechanism involved in the effect, are discussed in the last part. (C) 2001 Elsevier Science B.V, All rights reserved.