Chiral Nanochannels of Ordered Mesoporous Silica Constructed by a Pillar[5]arene-Based Host–Guest System

Abstract

The separation of racemic compounds by chiral nanochannels has attracted extensive attention. However, the fabrication of high-performance chiral nanochannels is still a challenge owing to the difficulty in magnifying the weak chiral interaction to macroscopic properties of materials. Herein, by introducing a l-alanine-pillar­[5]­arene host to achiral ordered mesoporous silica (OMS), chiral OMS nanochannels were fabricated, which exhibited excellent selectivity (ee value up to 90.2%) to separate racemic drugs with promising reusability and stability. Besides, it was identified that enantioselective separation took place through a molecular-recognition-adsorbed transport mechanism. This work highlights the great potential of chiral OMS nanochannels as a platform for enantioselective separation.

Chiral Covalent Organic Framework Packed Nanochannel Membrane for Enantioseparation

“…[12] Another strategy was size-matching, by reducing the diameter of transmission channel to 0.1-10 nm. [19,37] In this work, the chiral COF packed nanochannel performs well in the separation of chiral drugs (Table 1). Both strategies provide functionalized nanochannel membranes with a bright prospect in high-selective enantioseparation.…”

“…One efficient strategy is localized introduction of multiple receptors in the nanochannel [12] . Another strategy was size‐matching, by reducing the diameter of transmission channel to 0.1–10 nm [19, 37] . In this work, the chiral COF packed nanochannel performs well in the separation of chiral drugs (Table 1).…”

Super-Assembled Chiral Mesostructured Heteromembranes for Smart and Sensitive Couple-Accelerated Enantioseparation

“…For example, a poly­(vinylidene fluoride) ultrafiltration membrane blending with chiral mesoporous SiO 2 was developed, which exhibited an enhanced enantioseparation performance for d -tryptophan and the enantiomeric excess ( ee , given in %) value up to 55%. In another study, the chiral structure of OMS was prepared using l -alanine-pillar­[5]­arene decorated into the nonchiral OMS, which achieved an enantiomer separation of ( R )-propranolol. Until now, studies on enantioseparation in artificial membranes often modified chiral ligand anchored on the achiral membrane to selectively recognize and transport the target enantiomers. , However, this is still insufficient for sensitive and high-efficiency enantioselective transport owing to the inhomogeneous active sites and binding differences in affinity between enantiomers for the same ligand. − …”

Tailored Chiral Copper Selenide Nanochannels for Ultrasensitive Enantioselective Recognition and Detection

“…[21] Scientists have developed different platforms to study chiral channels as chiral sensors, [22] including cyclodextrin, [23] amino acid, [24] and synthetic chiral pillar[n]arene. [25] Va rious chiral materials and strategies are used in chiral recognition, including chiral metal surfaces [26] chiral frameworks, [27] chiral sheets,a nd membranes. [28] Herein, we constructed al arge-scale heterogeneous membrane system with at ailorable nanopore size and chiral ligands.T he heterogeneous membrane systems were composed of highly ordered negatively charged zero-dimensional Cu 2Àx Se NP arrays and constructed by an interfacial selfassembly technique.N egatively charged L-penicillamine (Lpen) was intercalated into aC u 2Àx Se (L-pen Cu 2Àx Se) membrane;this enabled high ionic rectification and endowed chiral selection.…”