A Model Nucleoside for Electron Injection into DNA: 5-Pyrenyl-2′-Deoxyribose This work was supported by the Deutsche Forschungsgemeinschaft (Wa 1386/7-1, Fi 721/3-1,3-4) and by the Fonds der Chemischen Industrie. N.A. and H.A.W. are grateful to Professor Horst Kessler, Technische Universität München, for the generous support.

Ultrafast intramolecular electron transfer results from the excitation of the pyrene-modified nucleoside 1. The dynamics and pH dependence of this process were investigated by steady-state fluorescence and femtosecond time-resolved transient absorption spectroscopy. These studies suggest that reductive electron transfer through DNA is not coupled to protonation.