Molecular Engineering to Achieve AIE-active Fluorophore with Near-infrared (NIR) Emission and Temperature-sensitive Property.

Near-infrared organic small molecule luminescent materials have the advantages of easy modification, high quantum efficiency, good biological affinity, and color adjustability; thus, have promising application prospects in the fields of photoelectric devices, sensitive detection, photodynamic therapy, and biomedical imaging. However, traditional organic luminescent molecules have the problems of short emission wavelength, aggregation-causing emission quenching, and low quantum yield. Herein, we successfully synthesized four D-π-A-D light-emitting molecules based on electron-withdrawing malonitrile group and different electron-donating arylamine groups. These compounds showed satisfactory solvatochromism, aggregation-induced emission, red and near-infrared fluorescence, high photoluminescence quantum efficiency and temperature response properties. This successful example of molecular engineering provides a valuable reference for the development of advanced NIR materials with AIE and temperature-sensitive properties.