Chiral recognition remains a central challenge in chemistry and materials science, with important implications for pharmaceuticals, agrochemical, and fine chemical industries, where an unwanted enantiomer can have significant adverse effects within living organisms. Metal-organic frameworks (MOFs), with their structural tunability and porous environments, have gained significant traction as a promising platform for new enantioselective sensing. Hydrogenated BINOL (H₈-BINOL) offers a versatile chiral building block for constructing fluorescent chiral MOF. Yet while a growing number of chiral fluorescent MOF sensors have been reported, the mechanism underlying their chiral recognition remains largely unexplored.
Conventional understanding attributes chiral recognition to chiral-chiral interactions, in which two chiral molecules transiently form diastereomers with differing spectroscopic properties. These interactions display chiral inversion, where the two enantiomeric hosts show opposite selectivity: if the (R)-host preferentially recognises one analyte enantiomer, the (S)-host preferentially recognises the other. A rarer and less understood phenomenon is chiral non-inversion, where both (R)- and (S)-hosts preferentially recognise the same analyte. Our work addresses this gap by introducing the concept of structural-chiral interactions: enantioselectivity that arises from structural features such as pore chemistry and framework topology rather than from conventional chiral-chiral interactions. This strategy reframes how enantioselectivity can be engineered, thereby broadening the range of materials available for enantioselective applications.