Stimuli-Responsive\nPhotoluminescent Molecular Tweezers\nfor Highly Enantioselective Discrimination of Chiral Primary Amines

To\naddress the challenge of chiral recognition in terms\nof efficiency\nand generality, we propose a novel fluorescence sensing approach by\nrationally designing metal-ion-responsive chiral molecular tweezers.\nThe flexible and adaptable molecular tweezers enable facile recognition\nof 31 structurally varied chiral primary amine compounds, including\namino acids, amino acid esters, and chiral amines. Notably, upon stimulation\nby zinc ions, the chiral molecular tweezers demonstrate a higher enantioselective\nfluorescence response. Combined density functional theory calculations\nreveal that the chiral sensing mechanism relies on differential reaction\nrates and potential hydrogen-bonding interactions between the two\nenantiomers and the chiral receptor, which results in one of the enantiomers\nforming a more abundant, stable, and structurally rigid complex with\nthe receptor, resulting in a significant increase in the fluorescence\nintensity and enantioselectivity. The stimuli-responsive molecular\ntweezers approach provides a novel strategy for precise stereocontrol\nand universality of chiral recognition, offering a promising tool\nfor applications in various fields.