The spectroscopy, dynamics, and electronic structure of pyrenyl–dU nucleosides: Pradical dot+/dUradical dot− charge transfer state photophysics

Various spectroscopies including UV–vis absorbance, emission, and emission quantum yield are combined with a variety of kinetics measurements including time resolved emission and nanosecond, picosecond, and femtosecond transient absorbance (TA) to systematize the Pradical dot+/dUradical dot− charge transfer (CT) state dynamics of a variety of pyrenyl–dU nucleoside conjugates in several solvents of varying polarity. These results are then analyzed further by means of electronic structure computations in vacuum and using two different solvent models. Finally, the excess electron dynamics of a number of DNA duplex structures substituted with two different pyrenyl–dU nucleosides and 5-XdU, where X=Br or F, electron traps are discussed in terms of achieving high yields of long-lived photoinduced CT products in DNA.