Cover Picture (Angew. Chem. Int. Ed. Engl. 3/1995)

The cover picture shows an intramolecular electron-transfer reaction through duplex DNA. The DNA has been covalently and site-specifically labeled with two different redox-active ruthenium complexes to produce a donor –DNA–acceptor system. After laser excitation, the kinetics of intramolecular electron transfer from Ru^II to Ru^III center through DNA was measured by transient-absorption techniques. This system is designed to delineate the roles of base sequence and π stacking in modulating the rates of long-range electron-transfer reactions. More about this elegant method for providing well-defined model systems to probe the important and topical issue of electron-transfer through DNA is reported by T. J. Meade and J. F. Kayyem on p. 352 ff.