Supramolecular electron donor–acceptor complexes formed by perylene diimide derivative and conjugated phenazines

Abstract

Novel electron acceptors are synthesized through methylation of dipyrido[3,2-a:2′,3′-c]-7-aza-phenazine and dibenzo[a,c]-7-aza-phenazine. Absorption and fluorescence titration experimental results suggest that these phenazine derivatives may bind to aspartic acid modified perylene diimide (PASP) with moderate apparent association constant K_a (2.94 × 10⁴ to 1.30 × 10⁶ M⁻¹). Solvent polarity, electron accepting ability and the phenazine derivative substituents all have an important effect on the binding strength of the PASP–phenazine complex. Photoinduced electron transfer from PASP to phenazine derivatives is confirmed by electrochemical, electron paramagnetic resonance (EPR) and time-resolved fluorescence experiments. The PASP–phenazine may form needle-like or rod-like nanostructures with lengths from 100 to 400 nm depending on their interaction model.