A metal–organic framework with chiral nanochannels for enantioselective fluorescence switching of amino alcohols

Abstract

The origin of chirality in metal–organic frameworks (MOFs) from achiral linkers remains largely unpredictable, as it mainly stems from the intrinsic arrangement of structural components within the framework. To date, only a handful of reports have explored the achiral ligands for chiral MOF synthesis; their potential for chiral molecular recognition remains a fascinating area of research. Here, we have synthesised a 3-D Co-bpy MOF with chiral nanopores using an achiral linker, which undergoes spontaneous chirality induction through asymmetric crystallization. The MOF crystallizes in a P4₁2₁2 chiral space group, featuring distinctive 4-fold helical chains generating chiral nanochannels along the c-axis. Remarkably, this structural arrangement enables Co-bpy to exhibit enantioselectivity among chiral amino alcohols by “turn-off” and “turn-off–on” type fluorescence responses for each, with a high enantioselectivity factor.