Red-emissive quinoxaline-based BODIHY: Aggregation-induced emission and multi-responsive properties

Two new BODIHY-based AIEgens DQB1 and DQB2 including quinoxaline and benzothiazole scaffold have been synthesized and characterized. Comprehensive photophysical properties of the compounds in solution and aggregated/solid state have been investigated and fine-tuned via structural modifications. These display quite high Stokes shift (≥5991 cm−1) in solution and aggregated/solid state. Further, these derivatives display faint emission in solution (THF), while bright yellow [λem; 560 nm (DQB1) and intense red λem; ∼650 nm (DQB2)] in aggregated state with good quantum yield [Φf; 17.5 (DQB1) and 23.2 (DQB2)], and represent a family of dye with good AIE characteristics. Both the systems display superior solid state emission and crystallization-induced red-shifted emission. It has been shown that the compounds under study exhibit multi-responsive characteristics toward external stimuli, particularly significant color tuning in solid state due to mechanical stress and acid/base vapors. Crystal structure analyses for both DQB1 and DQB2 revealed efficient J-type aggregation and vital role of the intermolecular interactions toward AIE and multi-responsive properties.