RUTHENIUM COMPLEXES AS LUMINESCENT REPORTERS OF DNA

Coordination chemistry provides a wealth of characteristics that may be exploited in probing nucleic acids. Structurally and stereochemically well-defined transition metal complexes have been designed to probe nucleic acid structure and the recognition process. Reactive transition metal complexes have been tethered onto DNA-binding moieties to report sensitively on their recognition characteristics. This chapter discusses coordination complexes that have been remarkably useful as spectroscopic tags. in particular, it describes the application of ruthenium complexes to probe nucleic acid structure and recognition. Polypyridyl complexes of ruthenium(II) and their derivatives possess several features that may be exploited in developing spectroscopic probes for nucleic acids. The complexes possess an intense metal-toligand charge transfer (MLCT) transition in the visible region which yields a luminscent excited state; the excited state characteristics of these complexes have been amply characterized. Most importantly, this transition is perturbed on binding to DNA. The complexes are coordinatively saturated. They are inert to substitution and are stable in aqueous solution. Because the complexes are octahedral and possess three bidentate ligands, the complexes are chiral. © 1993 Academic Press, Inc.