Visualized 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 of salicylaldehyde 4-butoxyaniline Schiff base ( SBA ) was deliberately designed and facilely synthesized, which exhibits unique self-recovery property from semi-ordered structure to ordered structure alongwith significant fluorescence change after grinding. The monitoring of the fluorescence change provides rich kinetic information including kinetic order, rate constants, half-life and apparent activation energy of the spontaneous molecular directed motion process. Unlike instrumental analytical methods such as PXRD and AFM, which only give the information of a stable state of samples, the fluorescence method provided a new perspective to real-time visualize spontaneous molecular directed motion in situ in solid state.