We report excellent correlations between the first negative threshold potentials (VTHs) for electricconduction, electrochemical potentials, and computed lowest unoccupied molecular orbital energies in aseries of phenylene−ethynylene oligomers bearing a sulfur-based anchoring unit and different electroactivesubstituents on the central benzene ring. The theoretical and electrochemical results strongly suggest thatthe peaks observed in the i−V curves have a true molecular origin and are associated with distinctunoccupied molecular levels of the compounds that are strongly localized on the central ring (except forcompound I). This localization might account for the existence of a long-lived radical−anion state thatpermits lateral electron hopping and leads to charge trapping and storage.
