Proton-Coupled Electron Transfer in DNA−Acrylamide Complexes

Abstract

A theoretical study of proton-coupled electron transfer (PCET) in the radical anionic thymine−acrylamide complex is presented. This study is based on a multistate continuum theory, in which the solute is represented by a multistate valence bond model, the solvent is described by a dielectric continuum, and the transferring hydrogen nucleus is represented by a quantum mechanical wave function. In this application, the ground and excited electronic states are calculated with the complete active space self-consistent-field (CASSCF) method, the electronic coupling for the electron transfer reaction is calculated with the generalized Mulliken−Hush method, and the solvation properties are calculated with the frequency-resolved cavity model. The influence of neighboring DNA base pairs is determined by studying solvated DNA−acrylamide models in addition to the solvated thymine−acrylamide complex. The calculations indicate that the final product corresponds to single electron transfer (ET) for the solvated thymine...