Full theoretical protocol for the design of metal-free organic electron donor-spacer-acceptor systems.

A user-friendly (time-dependent) density functional theory based algorithm is proposed to design new donor-spacer-acceptor systems for electron transfer reactions. This algorithm is focused on metal-free organic compounds, most of which contain aromatic or alkene moieties. The oxidation and reduction potentials are calculated, together with the excited-state energy difference including the zero-point energy and the structural properties required to calculate an electron transfer Gibbs free energy change. The proposed algorithm has been tested on well-known systems, while two new compounds are suggested for photoinduced intramolecular electron transfer reactions using this scheme. The methodology here presented is intended to be a tool for synthetic physical-chemists, allowing them to evaluate the properties of hypothetical systems before the synthesis, enabling the study of limitless combinations of donor-spacer-acceptor arrangements.