Datong Wu

A pair of redox-active 1D CCOFs were synthesized through imine-based condensation and effectively employed for the enantioselective recognition of various chiral carboxylic acids, regardless of whether they contain electroactive functional groups.

Core–shell structured mesoporous chiral SiO ₂ @nanosized MnO ₂ is prepared, which can be used for colorimetric discrimination of penicillamine enantiomers.

To date, the application of chiral covalent organic frameworks (CCOFs) as membranes has encountered considerable challenges in attaining high enantioselectivity. In this study, a pair of charged CCOFs, constructed from pyridinium units serving as the framework linkages, was synthesized via a bottom-up synthetic strategy. The incorporation of these irreversible bonds confers substantial stability, particularly under aqueous conditions. These porous chiral materials were subsequently incorporated into a polytetrafluoroethylene membrane, which functioned as the supporting substrate for membrane separation. The resulting membrane exhibited pronounced enantioselectivity toward mandelic acid, tryptophan, and phenylalanine. Enantioseparation analyses revealed that the (S)-CCOF possessed a strong affinity for l-enantiomers, facilitated by multiple intermolecular interactions. Notably, the ionic-pairing effect enhanced the retention of l-enantiomers within the membrane's cavity channels, thereby allowing d-enantiomers to permeate more readily through the porous structure. This separation strategy achieved a maximum enantiomeric excess of 96.2 ± 0.5%. Furthermore, the membrane demonstrated satisfactory reproducibility. In brief, these findings underscore the considerable potential of charged CCOFs to enhance functional performance in membrane-based enantioseparation processes.

A clamp-shaped chiral organic small molecule is designed as a fluorescent probe for discrimination and detection of tyrosine enantiomers.

Over the last twenty years, covalent organic frameworks (COFs) have emerged as a significant class of porous materials, garnering considerable attention due to their broad applicability in catalysis, separation processes,...

The fabrication of chiral covalent organic frameworks (CCOFs) with electrochemiluminescence (ECL) properties tailored for enantioselective sensing remains challenging. This study employs a post‐synthetic modification strategy to synthesize ionic CCOFs with pronounced ECL behavior. First, an achiral covalent organic framework is constructed via imine condensation. Subsequently, the imidazolyl group in the COF is covalently functionalized with optically pure, chlorine‐substituted chiral reagents, forming an imidazolium moiety. Within this engineered architecture, the imidazolium and pyrenyl units serve as the electron acceptor and donor components, respectively. The obtained ionic CCOFs exhibit strong ECL activity. When applied as chiral sensors, the achieved ECL‐active CCOFs demonstrate a consistent recognition pattern: ( S )‐CCOFs exhibit deeper ECL quenching toward ( S )‐analytes. The ECL intensity ratios between the ( R )‐ and ( S )‐analytes range from 1.6–13.1. Moreover, a robust correlation is observed between analyte concentration (or enantiomeric composition) and ECL intensity.

Chiral hollow polymer microspheres are synthesized and used for spectroscopic chiral discrimination of naproxen isomers.

Considering that numerous studies have shown pyridinium salts can be reduced electrochemically to form cationic radicals, we wonder whether these cationic radicals can further react with co-reactants to create excited-state species that display electrogenerated chemiluminescence (ECL). Herein, four tripyridinium salts were synthesized using a simple method, achieving relatively high yields of over 87%. Optical and electrochemical analyses revealed that these tripyridinium salts, which feature a large conjugated system, demonstrated notable electrochemical and photoluminescent properties. Most importantly, when paired with potassium persulfate as a co-reactant, distinct ECL behavior was observed even in water, with emissions detected at around 478 nm. The maximum ECL efficiency (Φ_ECL) of the synthesized salts, using Ru(bpy)₃ ²⁺ as a reference, was found to be 10.2%. Furthermore, we conducted a detailed investigation into the luminous mechanism behind ECL generation from the tripyridinium salts.

A surface molecularly imprinted chiral sensor is designed for colorimetric resolution of cysteine (Cys) enantiomers by utilizing oxidase mimicking of Mn₂O₃ and reducing capacity of Cys. As the templates, l-Cys is anchored to the Mn₂O₃ nanozymes through Mn-S bonds, and the resultant Mn₂O₃-l-Cys is coated by the rigid silicon dioxide (SiO₂) imprinting layer. After the l-Cys templates are removed by calcination, molecularly imprinted SiO₂@Mn₂O₃ (MI-SiO₂@Mn₂O₃) is obtained. Owing to the oxidase mimicking of Mn₂O₃, colorless 3,3',5,5'-tetramethylbenzidine (TMB) can be converted into blue oxidized TMB (oxTMB) by the MI-SiO₂@Mn₂O₃; while the blue colored oxTMB can be reduced to colorless TMB by the reductive Cys. Due to the higher affinity of MI-SiO₂@Mn₂O₃ for l-Cys, more d-Cys is left in the solution after the Cys enantiomers are respectively incubated with the MI-SiO₂@Mn₂O₃, which can make the fading of oxTMB easier. Therefore, colorimetric resolution of the Cys enantiomers can be achieved by the developed molecularly imprinted chiral sensor.