Dipole-Mediated\nRectification of Intramolecular Photoinduced\nCharge Separation and Charge Recombination

Abstract

Controlling charge transfer at a\nmolecular scale is critical for\nefficient light harvesting, energy conversion, and nanoelectronics.\nDipole-polarization electrets, the electrostatic analogue of magnets,\nprovide a means for “steering” electron transduction\nvia the local electric fields generated by their permanent electric\ndipoles. Here, we describe the first demonstration of the utility\nof anthranilamides, moieties with ordered dipoles, for controlling\nintramolecular charge transfer. Donor–acceptor dyads, each\ncontaining a single anthranilamide moiety, distinctly rectify both\nthe forward photoinduced electron transfer and the subsequent charge\nrecombination. Changes in the observed charge-transfer kinetics as\na function of media polarity were consistent with the anticipated\neffects of the anthranilamide molecular dipoles on the rectification.\nThe regioselectivity of electron transfer and the molecular dynamics\nof the dyads further modulated the observed kinetics, particularly\nfor charge recombination. These findings reveal the underlying complexity\nof dipole-induced effects on electron transfer and demonstrate unexplored\nparadigms for molecular rectifiers.