Chiral Metal-Organic Framework Nanostructures for Chiral Channel-Dependent Enantioselective Sensing

Chiral channels or pores are a fundamental feature of chiral metal-organic frameworks (CMOFs). However, the roles of chiral channels and pores have always been overlooked in enantioselective sensing based on the CMOFs. Aiming at the chiral sensing platforms of enantioselectivity with efficient electrochemical recognition, the L-His, L-Glu, and L-Lys have been introduced into the metal-organic framework (MOF) as CMOFs. Taking advantage of postsynthetic modifications (PSM), the resulting CMOFs (MOF-His/MOF-Glu/MOF-Lys) exhibit chiral channel dependence for different amino acid enantiomers. Ascribed to the introduction of chiral linkers, the nanomaterials with chiral channels of different sizes exhibit electrochemical recognition behaviors for electrochemical recognition of glutamate (Glu) enantiomers, tryptophan (Trp) enantiomers, and phenylalanine (Phe) enantiomers, which are evaluated in detail by differential pulse voltammetry (DPV). In addition, ascribed to the regulation of chirality information transmission through introducing chiral molecules of different sizes, the resolved nanomaterials reveal a unique adjustable chiral channel upon the addition of amino acid molecules, leading to passage of amino acid enantiomers of different sizes with excellent recognition efficiency. This work provides not only a design strategy for developing CMOFs with channel tunability but also an idea for the construction of an electrochemical sensing platform.