Homochiral Zeolitic Imidazolate Framework with Defined Chiral Microenvironment for Electrochemical Enantioselective Recognition

Abstract

The recognition and separation of chiral molecules with similar structure are of great industrial and biological importance. Development of highly efficient chiral recognition systems is crucial for the precise application of these chiral molecules. Herein, a homochiral zeolitic imidazolate frameworks (c‐ZIF) functionalized nanochannel device that exhibits an ideal platform for electrochemical enantioselective recognition is reported. Its distinct chiral binding cavity enables more sensitive discrimination of tryptophan (Trp) enantiomer pairs than other smaller chiral amino acids owing to its size matching to the target molecule. It is found that introducing neighboring aldehyde groups into the chiral cavity will result in an inferior chiral Trp recognition due to the decreased adsorption‐energy difference of D‐ and L‐Trp on the chiral sites. This study may provide an alternative strategy for designing efficient chiral recognition devices by utilizing the homochiral reticular materials and tailoring their chiral environments.

Pure Covalent-Organic Framework Membrane as a Label-Free Biomimetic Nanochannel for Sensitive and Selective Sensing of Chiral Flavor Substances

“…It is worth noting that one of the important bases of chiral recognition is surface-charge-governed ion transport . When the KCl electrolyte concentration was less than 0.01 M, the ionic transmembrane conductance of the COF membrane significantly deviates from the volume value (the ionic conductance of the bulk KCl electrolyte) (Figure S7c, black dashed line), indicating that the prepared COF membrane had the characteristic of the surface-charge-governed ion transport with the concentration of KCl no less than 0.01 M (Figure S7c).…”

“…The gating ratio of the S -flavor enantiomers was greater than that of the R -flavor enantiomers for each pair of enantiomers. Meanwhile, the selectivity values for R / S -propanediol, R / S -methylbutyric acid, and R / S -butanol were 1.33, 2.52, and 2.34, respectively, suggesting that the developed pure COF nanochannel platform was generally suitable for sensing other chiral flavor enantiomers . Moreover, the developed pure COF membrane nanochannel platform was successfully applied to sensing flavor substances with the enantiomer excess (ee) values of 55.2% (propanediol) and 72.4% (limonene) and the low detection limits of 36 (limonene) and 71 (propanediol) ng L –1 (Table ).…”

“…It is worth noting that one of the important bases of chiral recognition is surface-charge-governed ion transport. 55 When the KCl electrolyte concentration was less than 0.01 M, the ionic transmembrane conductance of the COF membrane significantly deviates from the volume value (the ionic conductance of the bulk KCl electrolyte) (Figure S7c, black dashed line), indicating that the prepared COF membrane had the characteristic of the surface-charge-governed ion transport with the concentration of KCl no less than 0.01 M (Figure S7c). Meanwhile, the nanochannel size of the prepared COF membrane was much smaller than the Debye length in 1 μM KCl, suggesting that the prepared pure COF membrane nanochannel was fully negatively charged and had the characteristic of the surface-charge-governed ion transport.…”

Chiral Discrimination of Penicillamine Enantiomers: The Role of Aggregation-Caused Quenching in Achieving High Selectivity

“…Chiral metal–organic frameworks (CMOFs) offer a unique advantage with their abundant metal coordination sites and tailored three-dimensional pores for specific guest molecules adsorption. – This allows for chemo-, regio-, and even enantioselectivity at the atomic level, a feat that is not possible with conventional chiral materials. However, the potential of CMOFs for specific racemic analytes in chiral ECL analysis has remained largely unexplored.…”

Enantioselective Target Transport-Mediated Nanozyme Decomposition for the Identification of Reducing Enantiomers in Asymmetric Nanochannel Arrays

“…In recent years, the development of enantioselective sensors to recognize different enantiomers has provided alternative options for chiral identification and determination. − Among them, nanochannel sensing systems for signal transduction, as emerging electrochemical platforms, have shown promising chiral sensing potential based on ionic transport properties. , Their main working principle involves an efficient regulation of the (i) surface charge, (ii) steric hindrance, and (iii) wettability properties of nanochannels through chiral sensing or its induced interfacial interactions . The above changes can be directly evaluated by measuring the current–voltage ( I – V ) properties.…”