Homochiral porous nanosheets for enantiomer sieving

Abstract

Protein pores are highly specific in binding to chiral substrates and in catalysing stereospecific reactions, because their active pockets are asymmetric and stereoselective. Chiral binding materials from molecular-level pores with high specificity have not been achieved because of problems with pore deformation and blocking . A promising solution is the self-assembly of single sheets where all pores are exposed to the environment, for example as metal-organic frameworks , polymers or non-covalent aromatic networks, but, typically, the pores are distant from the internal cavities with chirality. Here, we report the synthesis of homochiral porous nanosheets achieved by the 2D self-assembly of non-chiral macrocycles, with open/closed pore switching. Pore chirality is spontaneously induced by a twisted stack of dimeric macrocycles. The porous 2D structures can serve as enantiomer sieving membranes that exclusively capture a single enantiomer in a racemic mixture solution, with uptake capacity greater than 96%. Moreover, the entrapped guests inside the pores can be pumped out by pore closing triggered by external stimuli. This strategy could provide new opportunities for controlled molecule release, as well as for artificial cells.

Morphological Transformation between Orthogonal Dynamic Covalent Self‐Assembly of Imine‐Boroxine Hybrid Polymer Nanocapsules and Thin Films via Linker Exchange

“…The control over their precise structure and morphology is important because the practical properties of materials depend on their morphology. Polymer nanocapsules (NCs) with a hollow interior and thin films have drawn significant attention for various potential applications, including drug delivery, imaging, probe, filtration and separation, and molecular recognition 4–8. Developing methods for fabricating these nanomaterials is of utmost importance to broaden the structural foundation.…”

Fluorescence Turn‐on Synthetic Lipid Rafts on Supramolecular Sheets and Hierarchical Concanavalin A Assembly

“…For example of synthetic membranes, the lateral association of the aromatic rods in amphiphilic molecules leads into supramolecular 2D membrane structures . Aromatic macrocycles with oligoether dendron at the center of the aromatic plane self‐assemble into the porous 2D structures . The synthetic membranes based on aromatic amphiphiles showed significant fluorescence changes in response to guests or salts through the different supramolecular interactions in aqueous solutions.…”

“…[22] Aromatic macrocyclesw ith oligoether dendron at the centero ft he aromatic plane self-assemble into the porous 2D structures. [23,24] The synthetic membranes based on aromatic amphiphiles showed significant fluorescence changes in response to guests or salts through the different supramolecular interactions in aqueous solutions. Therefore, the controlled self-assembly of synthetic aromatic amphiphilesi sb ecoming more and more a laboratory tool for sophisticated constructionso ff unctional nanostructures.…”

Supramolecular assembly of bent dinuclear amphiphilic alkynylplatinum(ii) terpyridine complexes: diverse nanostructures through subtle tuning of the mode of molecular stacking

“…Among the nanostructures reported, ordered porous networks, which are considered as one of the most important structures in nanotechnology, have found their utility in catalysis, 31 enantiomer sieving, 31 molecular recognition, 31,32 surface adsorption, 32 membrane channels 33 and lithium storage 34 by rational molecular design. 31 Therefore, exploring ways of producing ordered porous networks and manipulating pore sizes to perform a certain function are of paramount signicance. One of the approaches to fabricating regular porous networks is by breath gure, 35 in which water droplets condense onto a substrate containing a solution capable of stabilizing the water droplets and facilitate the formation of an array of pores before evaporating.…”

“…36 Another strategy is by molecular stacking, which makes use of molecules of rationally designed shapes and angles to form the desired porous network structure. 31,32 For instance, rigid hexagonal macrocycles and bent molecules have been used to form porous network through dimeric stacks, 31 or through electrostatic spreading of pre-assembled macrocycles. 32 There have also been reports where metal coordination plays a role to assist formation of monomeric pores before aggregation to form a porous network by molecular stacking.…”