An unusual one-donor-two-acceptor interaction in a pair of covalently bridged naphthalenediimide dimers

Abstract

An unusual donor–acceptor (D–A) state is reported in a pair of regioisomeric xylylene-bridged naphthalenediimide (NDI) dimers. The D–A state is characterized by a weak, red-shifted absorbance and a photoluminescence (PL) with a very high quantum efficiency. PL and PL excitation (PLE) spectroscopy reveals the partial charge-transfer character of the D–A state. Disruption of this D–A interaction in the presence of a competing donor, reveals the unique one-donor-two-acceptors stoichiometry. Finally, the effect of intramolecular pi-stacking on the D–A interaction is discussed.