Utilizing aggregation-induced emission phenomenon to visualize spontaneous molecular directed motion in solid state
The real-time monitoring of spontaneous molecular directed motion is a highly important but very challenging task. In this work, a rod-like aggregation-induced emission (AIE) molecule was carefully designed and facilely synthesized. The AIE molecule, salicylaldehyde 4-butoxyaniline Schiff base (SBA), exhibited unique self-recovery property from semi-ordered structure to ordered structure along with significant fluorescence change after grinding. The fluorescence changes were monitored to obtain important kinetic information regarding the spontaneous molecular directed motion process, including kinetic order, rate constants, half-life, and apparent activation energy. Unlike instrumental analytical methods such as PXRD and AFM, which only give the information of a stable state of samples, the proposed fluorescence method provided a new perspective to real-time visualize spontaneous molecular directed motion in situ in solid state.