Asymmetric tetraphenyl-substituted butadienes with aggregation-induced emission characteristic: Synthesis, properties and applications

Six asymmetric tetraphenyl-1,3-butadiene derivatives were firstly designed and synthesized. Their photophysical properties showed the six derivatives having aggregation-induced emission (AIE) characteristics. The single crystal structure of indanedione-containing tetraphenyl-1,3-butadiene showed that the distorted structure and a variety of strong intermolecular interactions limited the intramolecular movement to enhance the fluorescence emission. Cyanoacetate-containing tetraphenyl-1,3-butadiene (TPB-NC) and dimethylbarbituric-containing tet-raphenyl-1,3-butadiene (TPB-BC) exhibited typical mechanofluorochromic (MFC) properties. Powder X-ray diffraction and polarizing microscope experiments were carried out to reveal the mechanochemical mechanism, and the results showed that MFC was mainly attributed to a transition from crystalline state to amorphous state. In addition, TPB-NC could selectively respond to butyl cholinesterase (BuChE) and glycyrrhetinic acid (GA) in real-time. The low limit of detection for BuChE and GA were 1.61 mu g/mL and 0.03 mu g/mL according to IUPAC-based approach, respectively. The work has significant role in guiding the design of AIE molecules and enlarging their applications.