Supramolecular gelators enabling chiral organogels for naked-eye enantiodifferentiation with wide accessibility and applicability

Abstract

Techniques to acquire chiral information from molecules are essential for deciphering important biological processes and improving the performance of industrial chiral materials. Herein, we report novel supramolecular gelators that enable widely accessible chiral supramolecular organogels for simple naked-eye enantiodifferentiation of specific enantiomers (left- or right-handedness) for wide-range substances. The supramolecular gelators featuring multiple hydrogen-bonding sites and large π-π conjugated groups are produced by complexing commercially available chiral tartaric acids and achiral 1-naphthylmethylamine. The highly polar and insoluble acid-amine complexes drive the aggregation of the supramolecular gelators, which further form chiral nanofibers due to chirality transfer from tartaric acid to the supramolecular nanofibers through multiple hydrogen-bonding between the hydroxyl groups of chiral tartaric acids and π-π stacking between 1-naphthylmethylamine molecules. At high concentrations, physical crosslinking of the chiral nanofibers creates a chiral gel structure that facilitates interactions between its chirally and non-covalently associated components and enantiomers, making the gel system particularly sensitive to specific types of enantiomers. Consequently, sensitive naked-eye detection of specific enantiomers of diverse substances is achieved via observing “gel-to-micelle” transitions, which occurs when the enantiomers generate complexes that disrupt chirality transfer in the co-assembly and destroy the hierarchical structures.