AIE-active fluorescence emitters containing tetraphenylethylene and α-cyanostilbene with mechanochromism and photo-responsive behaviors

Aggregation induced emission luminogens (AIEgens) as one of the optimal alternatives for designing stimuli-responsive fluorophores for real-life applications have sparked much current interest in smart materials design. Herein, the “Star molecules” in AIEgens of α-cyanostilbene and Tetraphenylethylene (TPE) derivatives were constructed into one molecular, namely DC-TPE-tBu and DC-TPE-CN. Both compounds exhibited significant AIE properties. Moreover, the two compounds could change their luminescent colors and intensities under the stimulation of external mechanical force and UV light, showing excellent mechanochromic luminescent (MCL) and remarkable photo-responsive behaviors, respectively. The stimuli responsive mechanisms were investigated by powder X-Ray diffractometer (PXRD) spectra and density functional theory calculations (DFT). The MLC behaviors were associated with the crystalline-to-amorphous transitions after mechanical grinding. These remarkable features make them suitable for the application of mechano/photo-sensors. The studies provide a useful strategy for developing AIE-active functional materials.