AIE Stereoisomers with Huge Differences in Luminescence Behavior and Biomedical Activity

Stereoisomers that differ only in spatial orientation of their atoms could exhibit distinctive properties and have attracted immense interest in drug development and material science. Herein, a series of AIE-featured stereoisomers with pronounced difference in luminescent and biomedical activities were efficiently synthesized and easily purified. One of the isomers in the E/Z pair is emissive with high fluorescence quantum yield at room temperature, while the other one is nearly non-emissive. As the isomers could transform between each other under UV irradiation, the light-up cell imaging was successfully demonstrated using the non-emissive isomer as a turn-on probe via isomerization process. Analysis of crystal packing patterns illustrated that the contrasts in void space possibly caused the difference in molecular motion and thus led to their distinct luminescence properties. Further, the E/Z isomers displayed remarkable difference in enzymatic conversion rates and cellular toxicities for several cancer cell lines. The distinctive luminescence properties of the isomeric pair provided a powerful tool to image those divergencies in biomedical activity, holding great potential for visualizable drug screening and development.