Visualization of enantiorecognition by excited-state conformation modulation

Chiral purity is crucial in life sciences, emphasizing the importance of precise enantiomeric identification and the development of analytical techniques. Here, we design functional dyes with visual chiral recognition capabilities by introducing recognition units 2-amino-1,2-diphenylethanol into vibration-induced emission molecules. The unambiguous differentiation in luminescent colors upon binding to enantiomers facilitates the efficient recognition of enantiomers and the analysis of enantiomeric excess. The chiral recognition process originates from co-assembly under charge-aided hydrogen bonding interactions, which is significantly impacted by the steric hindrance effect, and further affects the planarization of the excited state conformation of the dye. This co-assembly process precisely amplifies the dynamics at the molecular level into macroscopic observable signals for real-time, highly sensitive recognition. Furthermore, we establish a sophisticated optical analysis system by correlating Red-Green-Blue values and CIE coordinates to analyze the enantiomeric excess of chiral molecules. This work opens a distinct avenue for visual chiral recognition and inspires the development of advanced optical materials in chiral sensing chemistry. Techniques for determining chiral purity are important, but can be challenging to achieve by eye. Here, the authors report the development of dyes with visual chiral recognition capabilities by changes in the coassembly process and therefore variable steric hindrance.