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

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 x 10(4) to 1.30 x 10(6) 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.