Associative return electron transfer.A bond-coupled electron transfer in the photoreactions of cyclopropylamines

摘要

The dynamics of the geminate radical-ions paris formed by electron transfer to the excited states of cyanoanthracenes from 2-phenylcyclopropylamines are dominated by exothermic bond cleavage of the amine radical cations.Quantitative studies of product formation as a function of the energetics of the photochemical and corresponding thermal reactions provide support for a novel mechanism in which return electron transfer in the geminate pair occurs in concert with bond formation from the ring-opened radical cations this bond-coupled electron tansfer process is freerred to as an associative return electon transfer reactin.The important features of the associative electron trransfer process that explain the experimental observations sre described in terms of potential energy surfaces and compoetition between adiabatic and non-adiabatic deactivation paths.