Charge transfer of 1,3,4‐oxadiazole derivative, its functional polymers and study of their different aggregation‐induced emission enhancement behaviors

Abstract In this study, a symmetrical D‐π‐A‐π‐D initiator ViOXD, based on substituted amino donor (D) and 1,3,4‐oxadiazole acceptor (A), with rigid stilbene π‐bridge was synthesized. The photophysical investigation of ViOXD in solution and aggregate state showed its solvatochromic and aggregation‐caused quenching characteristics, because of its strong charge transfer and the formation of H‐aggregates, respectively. The introduction of peripheral polystyrene or carbazole‐containing PVPCz chains via atom transfer radical polymerization not only recovered the fluorescence of the ViOXD core, but also tuned its maximum emission wavelength in aggregate state, due to the stronger electron‐donating ability and better conjugation of PVPCz chains than polystyrene chains. On the other hand, the large conjugation length and symmetrical charge transfer from the ends to the cores of ViOXD facilitated the electronic delocalization and bestowed the end‐functionalized polymers with good fluorescence in aggregate state, which we have applied in cellular imaging by preparation of their fluorescent nanoparticles.