Solvent effects on excited-state electron-transfer rate of pyrene-labeled deoxyuridine: A theoretical study

Highlights: Explicit solvent effects on the excited-state electron-transfer rate constants are presented. Difference between protic and aprotic solvents are shown in detail. Hydrogen bond between solvent and solute causes enhancement of excited-state electron-transfer rate. Combined density functional and classical molecular dynamics simulation results are demonstrated. Excited-state electron-transfer rates are evaluated on the basis of a Marcus theory. Solvent effects on the quenching process from the first excited state of 5-(1-pyrenyl)-2⿲-deoxyuridine (Py-dU) were theoretically examined. Our results suggest that the excited-state electron transfer occurs without the so-called proton-coupled electron transfer process, which supports experimental results. Although there are no remarkable differences observed in the structure and the corresponding S₁ excitation energy between the solutions of MeOH and MeCN within a polarizable continuum model, we report here that hydrogen bonds between the explicit MeOH molecule with the dU moiety, whose structure was frequently found in molecular dynamics simulations, result in an enhancement of the electron-transfer rate constant.