Engineering Isomeric AIEgens Containing Tetraphenylpyrazine for Dual Memory Storage

Tetraphenylpyrazine (TPP) is a promising heterocycle-based aggregation-induced emission luminogen (AIEgen) which has sparked multiple applications in organic light-emitting diodes, sensors, and biotherapy. However, the utility of it in developing information storage materials is relatively rare. Moreover, TPP is mostly employed as an electronic acceptor in molecular design, while the consideration of it as an electronic donor is attractive in studies which may provide a full understanding of its property to tailor the materials. In this work, we synthesize three TPP-based molecules by decorating it with acrylonitrile and isomeric pyridine units, which show AIE behavior by property inheritance from their parent unit. Interestingly, the effective intramolecular charge transfer takes place from the TPP electronic donor to the acrylonitrile and pyridine electronic acceptor, therefore inducing a remarkable solvatochromic effect as the solvent polarity improves. Moreover, it is revealed that the isomeric effect of the nitrogen atom in the pyridines may pose an influence on the absorption, solvatochromism, and AIE behavior. In addition, the acrylonitrile and pyridine groups are reactive to light and acid-base stimuli with irreversible and reversible responses, respectively. Combined with the high light-harvesting ability of these AIEgens, they show great potential in the stimuli-responsive materials for dual information storage.