Three-State Switchable Chiral Stationary Phase Based on Helicity Control of an Optically Active Poly(phenylacetylene) Derivative by Using Metal Cations in the Solid State

Stimuli-responsive synthetic helical polymers

Synthetic dynamic helical polymers (supramolecular and covalent) and foldamers share the helix as a structural motif. Although the materials are different, these systems also share many structural properties, such as helix induction or conformational communication mechanisms. The introduction of stimuli responsive building blocks or monomer repeating units in these materials triggers conformational or structural changes, due to the presence/absence of the external stimulus, which are transmitted to the helix resulting in different effects, such as assymetry amplification, helix inversion or even changes in the helical scaffold (elongation, J/H helical aggregates). In this review, we show through selected examples how different stimuli (e.g., temperature, solvents, cations, anions, redox, chiral additives, pH or light) can alter the helical structures of dynamic helical polymers (covalent and supramolecular) and foldamers acting on the conformational composition or molecular structure of their components, which is also transmitted to the macromolecular helical structure.

Unraveling Dynamic Helicity Inversion and Chirality Transfer through the Synthesis of Discrete Azobenzene Oligomers by an Iterative Exponential Growth Strategy

Unraveling the chirality transfer mechanism of polymer assemblies and controlling their handedness is beneficial for exploring the origin of hierarchical chirality and developing smart materials with desired chiroptical activities. However, polydisperse polymers often lead to an ambiguous or statistical evaluation of the structure-property relationship, and it remains unclear how the iterative number of repeating units function in the helicity inversion of polymer assemblies. Herein, we report the macroscopic helicity and dynamic manipulation of the chiroptical activity of supramolecular assemblies from discrete azobenzene-containing oligomers (azooligomers), together with the helicity inversion and morphological transition achieved solely by changing the iterative chain lengths. The corresponding assemblies also differ from their polydisperse counterparts in terms of thermodynamic properties, chiroptical activities, and morphological control.

Thermo-responsive chiral micelles as recyclable organocatalyst for asymmetric Rauhut-Currier reaction in water

Developing eco-friendly chiral organocatalysts with the combined advantages of homogeneous catalysis and heterogeneous processes is greatly desired. In this work, a family of amphiphilic one-handed helical polyisocyanides bearing phosphine pendants is prepared, which self-assembles into well-defined chiral micelles in water and showed thermo-responsiveness with a cloud point of approximately 38.4 °C. The micelles with abundant phosphine moieties at the interior efficiently catalyze asymmetric cross Rauhut-Currier reaction in water. Various water-insoluble substrates are transferred to target products in high yield with excellent enantioselectivity. The yield and enantiomeric excess (ee) of the product generated in water are up to 90% and 96%, respectively. Meanwhile, the yields of the same R-C reaction catalyzed by the polymer itself in organic solvents is <16%, with an ee < 72%. The homogeneous reaction of the chiral micelles in water turns to heterogeneous at temperatures higher than the cloud point, and the catalyst precipitation facilitates product isolation and catalyst recovery. The polymer catalyst is recycled 10 times while maintaining activity and enantioselectivity.

Construction of metallo-helicoids with high antimicrobial activity via intermolecular coordination

Metallo-helicoids are constructed by intermolecular coordination interactions between covalent linear polymer and tritopic/hexatopic molecular templates. These metallo-polymers with helicoidal conformation exhibit high antimicrobial activities against both Gram-positive and Gram-negative pathogens.

Recent advances of optically active helical polymers as adsorbents and chiral stationary phases for chiral resolution

Chiral resolution is very important and still a big challenge due to different biological activity and same physicochemical property of one pair (R)- and (S)-isomer. There is no doubt that chiral selectors are essentially needed for chiral resolution, which can stereoselectively interact with a pair of isomers. To date, a large amount of optically active helical polymers as chiral selectors have been synthesized via two strategies. First, the target helical polymers are derived from natural polysaccharide such as cellulose and amylose. Second, they can be synthesized by polymerization of chiral monomers. Alternatively, an achiral polymer is prepared first followed by static or dynamic chiral induction. Furthermore, a part of them is harnessed as chiral stationary phases for chromatographic chiral separation and as chiral adsorbents for enantioselective adsorption/crystallization, resulting in good enantioseparation efficiency. In summary, the present review will focus on recent progress of the polymers with optical activity for chiral resolution, especially the literature published in the past 10 years. In addition, development prospects and future challenges of optically active helical polymers will be discussed in detail.

Screw sense excess and reversals of helical polymers in solution

The helix reversal is a structural motif found in helical polymers in the solid state, but whose existence is elusive in solution. Herein, we have shown how the photochemical electrocyclization (PEC) of poly(phenylacetylene)s (PPAs) can be used to determine not only the presence of helix reversals in polymer solution, but also to estimate the screw sense excess. To perform these studies, we used a library of well folded PPAs and different copolymers series made by enantiomeric comonomers that show chiral conflict effect. The results obtained indicate that the PEC of a PPA will depend on the helical scaffold adopted by the PPA backbone and on its folding degree. Then, from these studies it is possible to determine the screw sense excess of a PPA, highly important in applications such as chiral stationary phases in HPLC or asymmetric synthesis.

Asymmetric Polymerization-Induced Crystallization-Driven Self-Assembly of Helical, Rod-Coil Poly(aryl isocyanide) Block Copolymers

Polymerization-induced crystallization-driven self-assembly (PI-CDSA) is combined, for the first time, with helical, rod-coil block copolymer (BCP) self-assembly to enable scalable and controllable in situ synthesis of chiral nanostructures of variable shape, size, and dimensionality. Herein, we report newly developed asymmetric PI-CDSA (A-PI-CDSA) methodologies in the synthesis and in situ self-assembly of chiral, rod-coil BCPs composed of poly(aryl isocyanide) (PAIC) rigid-rod and poly(ethylene glycol) (PEG) random-coil components. Using PEG-based nickel(II) macroinitiators, the construction of PAIC-BCP nanostructures with variable chiral morphologies is accomplished at solids contents ranging 5.0-10 wt %. At low core-to-corona ratios for PAIC-BCPs, we demonstrate the scalable formation of chiral one-dimensional (1D) nanofibers via "living" A-PI-CDSA whose contour lengths can be tuned through alterations to unimer-to-1D seed particle ratio. At high core-to-corona ratios, A-PI-CDSA was implemented for the rapid fabrication of molecularly thin, uniform hexagonal nanosheets via spontaneous nucleation and growth aided by vortex agitation. Investigations into 2D seeded, living A-PI-CDSA revealed a brand-new paradigm in the context of CDSA where hierarchically chiral, M helical spirangle morphologies (i.e., hexagonal helicoids) are size-tuned in three dimensions (i.e., heights and areas) via alterations to unimer-to-seed ratio. These unique nanostructures are formed in situ at scalable solids contents up to 10 wt % via rapid crystallization about screw dislocation defect sites in an enantioselective fashion. The liquid crystalline nature of PAIC blocks dictates the hierarchical assembly of these BCPs, with chirality translated across length scales and in multiple dimensions affording large amplifications in chiroptical activity with g-factors reaching -0.030 for spirangle nanostructures.

Visible Helicity Induction and Memory in Polyallene toward Circularly Polarized Luminescence, Helicity Discrimination, and Enantiomer Separation

Inspired by biological helices (e.g., DNA), artificial helical polymers have attracted intense attention. However, precise synthesis of one-handed helices from achiral materials remains a formidable challenge. Herein, a series of achiral poly(biphenyl allene)s with controlled molar mass and low dispersity were prepared and induced into one-handed helices using chiral amines and alcohols. The induced one-handed helix was simultaneously memorized, even after the chiral inducer was removed. The switchable induction processes were visible to naked eye; the achiral polymers exhibited blue emission (irradiated at 365 nm), whereas the induced one-handed helices exhibited cyan emission with clear circularly polarized luminescence. The induced helices formed stable gels in various solvents with helicity discrimination ability: the same-handed helix gels were self-healing, whereas the gels of opposite-handed helicity were self-sorted. Moreover, the induced helices could separate enantiomers via enantioselective crystallization with high efficiency and switchable enantioselectivity.

Diastereomeric multi-chiral pendant groups: Their key role in stimuli-responsive polymeric responses

Chiral information transmission in helical polymers bearing multi-chiral pendant groups is usually determined by the absolute configuration of the first chiral center. The second chiral residue usually has low-to-null influence in the macromolecular handedness of the polymer, due to its remote position respect to the polyene main chain. Here, we demonstrate how the stimuli responsive properties of diastereomeric polymers, obtained by changing the absolute configuration of the second chiral center, are different due to the unlike properties of diastereoisomers.

Switchable Separation Strategy via Host-Guest Locks

Universal separation strategies are the ultimate goal in separation science. However, there is always a tradeoff between universality and selectivity due to the negative influence among different recognition domains. With the goal of universal separation in mind, an unprecedented, switchable, and versatile separation strategy using reversible supramolecular host-guest interactions has been developed. These adjustable separation mediums were prepared using surface-grafted cationic cyclodextrin to firmly bind negatively charged adamantane derivatives. By changing guest structures, the surface functionality of the separation medium can be precisely regulated to be selective for a variety of substrates including chiral or achiral molecules, thus producing satisfactory single-column universality. This method offers a new approach to move beyond conventional separation methodologies and should stimulate the design of switchable functional materials.

Self-Assembly of Helical Nanofibrous Chiral Covalent Organic Frameworks

Despite significant progress on the design and synthesis of covalent organic frameworks (COFs), precise control over microstructures of such materials remains challenging. Herein, two chiral COFs with well-defined one-handed double-helical nanofibrous morphologies were constructed via an unprecedented template-free method, capitalizing on the diastereoselective formation of aminal linkages. Detailed time-dependent experiments reveal the spontaneous transformation of initial rod-like aggregates into the double-helical microstructures. We have further demonstrated that the helical chirality and circular dichroism signal can be facilely inversed by simply adjusting the amount of acetic acid during synthesis. Moreover, by transferring chirality to achiral fluorescent molecular adsorbents, the helical COF nanostructures can effectively induce circularly polarized luminescence with the highest luminescent asymmetric factor (g_lum ) up to ≈0.01.

Full Control of the Chiral Overpass Effect in Helical Polymers: P/M Screw Sense Induction by Remote Chiral Centers After Bypassing the First Chiral Residue

In helical polymers, helical sense induction is usually commanded by teleinduction mechanism, where the largest substituent of the chiral residue directly attached to the main chain is the one that commands the helical sense. In this work, different helical structures with different helical senses are induced in a helical polymer [poly-(phenylacetylene)] when the conformational composition of two different dihedral angles of a pendant group with more than two chiral residues is tamed. Thus, while the dihedral angle at chiral residue 1 [(R)- or (S)-alanine], attached to the backbone, produces an extended or bent conformation in the pendant resulting in two scaffolds with different stretching degree, the second dihedral angle at chiral residue 2 [(R)- or (S)-methoxyphenylacetamide] places the substituents of this chiral center in a different spatial orientation, originating opposite helical senses at the polymer that are induced through a total control of the "chiral overpass effect".

Photostability and Dynamic Helical Behavior in Chiral Poly(phenylacetylene)s with a Preferred Screw‐Sense

Helical polymers such as poly(phenylacetylene)s (PPAs) are interesting materials due to the possibility of tuning their helical scaffold (sense and elongation) once they have been prepared and by the presence of external stimuli. The main limitation in the application of PPAs is their poor photostability. These polymers degrade under visible light exposure through a photochemical electrocyclization process. In this work, it was demonstrated, through a selected example, how the photochemical degradation in PPAs is directly related to their dynamic helical behavior. Thus, while PPAs with dynamic helical structures show poor photostability under UV/Vis light exposure, poly‐(R)‐1, bearing an enantiopure sulfoxide group as pendant group and designed to have a quasi‐static helical behavior, shows a large photostability due to the restricted conformational composition at the polyene backbone, needed to orient the conjugated double bonds prior to the photochemical electrocyclization process and the subsequent degradation of the material.

Helix Induction and Inversion of Polymeric Foldamer Regulated by the Single Enantiomers

In general, a single enantiomer can induce a foldamer into a preferred-handed helix, while another condition is required for the helical inversion. In this work, it is found that the helix induction and subsequent inversion of the poly(m-phenylene diethynylene)-based foldamer bearing aza-18-crown-6 pendants (Poly-1) can be realized by increasing the concentration of sterically hindered L-amino acid perchlorate salts. When the amount of chiral enantiomers is small, one enantiomer tends to complex with two non-adjacent aza-18-crown-6 rings via three N⁺ -H···O hydrogen bonds in a sandwich mode. Notably, the transition dipole moment is perpendicular to aza-18-crown-6 ring, so that the induced helical chirality in Poly-1 main chain is opposite to the chirality of enantiomers. When the amount of chiral enantiomers is large enough, each aza-18-crown-6 is occupied by one enantiomer, which causes the transition dipole moment in a parallel direction to aza-18-crown-6 ring. In this case, the increased steric hindrance can facilitate the inversion of screw sense of Poly-1 main chain, which is directed by chiral center of enantiomers. As a result, a helix inversion has been achieved successfully. This work not only provides a novel strategy for regulating the two-stage folded helical conformations by the single enantiomers, but opens a window to develop chiral recognition materials. This article is protected by copyright. All rights reserved.

Solvent-dependent helix inversion in optically active poly(diphenylacetylene)s and their chiral recognition abilities as chiral stationary phases for high-performance liquid chromatography

We report the first example of solvent-dependent helix inversion in poly(diphenylacetylene) (PDPA) derivatives. Asymmetrically substituted PDPAs bearing optically active substituents linked through amide bonds formed preferred-handed helical conformations because of the optically active substituents in the pendants, whose helix-senses were inverted upon thermal annealing in polar solvents such as N,N-dimethylformamide and dimethylsulfoxide and in nonpolar solvents such as tetrachloroethane. Unlike the solvent-dependent helix inversion reported for other dynamic helical polymers, the macromolecular helicity induced in the polymer backbone of these PDPAs upon thermal annealing was stably maintained at room temperature, independent of the solvent polarity. These diastereomeric PDPAs with opposite helix-senses generated almost mirror-imaged left- and right-handed circularly polarized light in the same solvent at room temperature. Taking advantage of this unique solvent-dependent helix inversion property, the diastereomeric PDPAs with opposite helix-senses were coated on macroporous silica gel and applied to chiral stationary phases for high-performance liquid chromatography. Despite having the same optically active substituents on the pendant phenyl rings, they showed completely different chiral recognition abilities toward many racemates depending on the helix-sense of the polymer backbone, and the elution order of the enantiomers was reversed for some racemates. The combination of the helix-sense of the polymer backbone and the chirality of the pendants, which afforded a higher chiral recognition ability, differed depending on the racemates.

Effect of pendant stereostructure on backbone conformation and enantioseparation ability of helical polyacetylene-based chiral stationary phases

Six proline-derived acetylene monomers bearing either two stereocenters (S-mR, S-mS, R-mS, Rac-mS and S-mRac) or one stereocenter (S-mBn) were obtained from commercially available N-(tert-butoxycarbonyl)-prolinal. Under the catalysis of Rh-diene complex, they were converted to the corresponding optically active helical polymers, S-pR, S-pS, R-pS, Rac-pS, S-pRac, and S-pBn. The correlations between configuration and position of stereocenters in pendants with the polymer conformation as well as chiral resolution performance were systematically explored by a combination of nuclear magnetic resonance (NMR), Raman, UV-Vis absorption, electronic/vibration circular dichroism spectroscopies, high-performance liquid chromatography (HPLC), and computational simulation. The configuration of the stereocenter adjacent to polymer mainchain determined the sense of helical conformation and the elution order of analytes, while that of the remote one affected the arrangement of pendants and the scope of analytes that could be discriminated. Among 18 aromatic analytes selected, S-pR could discriminate 10, while S-pS recognized 12. The racemization of adjacent or remote stereocenters greatly reduced the scope of analytes that could be resolved. Based on computer simulations, S-pS had larger recognition space than S-pR, favoring the steric fit with the racemates containing axial chirality. The strength and number of intermolecular hydrogen bondings between enantiomers and CSPs predominantly determined the chiral discrimination.

Recent advances in helical polyacetylene derivatives used as coated chiral stationary phases for enantioseparation

The development of helical polyacetylene derivatives bearing different kinds of chiral pendants and the enantioseparation based on these helical polymers as coated CSPs for HPLC will be described.

Recent Advances in Polyallenes: Preparation, Self-Assembly, and Stimuli-Responsiveness

Polyallenes, as a typical type of reactive polymers, are of great significance and have aroused widespread interest because they contain double bonds that can be post-modified into other functionalities to afford varieties of functional materials. This Minireview firstly highlights the recent advances in the preparation of polyallenes, including preparation of helical polyallenes through directly polymerization of chiral allene monomers or helix-sense-selective polymerization (HSSP) of achiral allene monomers, synthesis of 1,2-regulated polyallenes and 2,3-regulated polyallenes via selective polymerization of allene monomers, polymerization of allene monomers catalyzed by Ni(II)-terminated poly(3-hexylthiophene) (P3HT), and so on. Then, latest progress on the self-assembly and stimuli-responses of polyallene-based diblock, ABA and ABC triblock copolymers is summarized. We hope this Minireview will inspire more interest in developing polyallenes and encourage further advances in functional materials.

Macromolecular helicity induction and static helicity memory of poly(biphenylylacetylene)s bearing aromatic pendant groups and their use as chiral stationary phases for high-performance liquid chromatography

Two novel poly(biphenylylacetylene)s (PBPAs) bearing achiral alkylphenyl groups at the 4'-position of the biphenyl pendant through ester linkers with different sequences were synthesized by the rhodium-catalyzed polymerization of the corresponding monomers. The influence of the alkylphenyl pendants and the ester sequences on the macromolecular helicity induction and subsequent static helicity memory was investigated. In addition, the chiral recognition ability as chiral stationary phases for high-performance liquid chromatography of the helicity-memorized PBPAs was also examined. Both polymers formed almost perfect right- and left-handed helical conformations through noncovalent chiral interactions with enantiomeric alcohols, and their induced macromolecular helicities were completely retained ("memorized") after removal of the helix inducer. A PBPA bearing a 4-n-butylphenoxycarbonyl pendant group with a static helicity memory showed a remarkably high chiral recognition ability toward a wide variety of chiral aromatics, including simple point chiral compounds, axially chiral biaryls, a chiral spiro compound, helicenes, and planar chiral cyclophanes, particularly under the reversed-phase conditions.

Recent progress in the development of chiral stationary phases for high-performance liquid chromatography

Separations and analyses of chiral compounds are important in many fields, including pharmaceutical production, preparation of chemical intermediates, and biochemistry. High-performance liquid chromatography using a chiral stationary phase is regarded as one of the most valuable methods for enantiomeric separation and analysis because it is highly efficient, is broadly applicable, and has powerful separation capability. The focus for development of this method is the identification of novel chiral stationary phases with superior recognition performance and good stability. The present article reviews recent progress in the development of new chiral stationary phases for high-performance liquid chromatography between January 2018 and June 2021. These newly reported chiral stationary phases are divided into three categories: small organic molecule-based (cyclodextrin and its derivatives, macrocyclic antibiotics, cinchona alkaloids, and other low molecular weight chiral molecules), macromolecule-based (cellulose and amylose derivatives, chitin and chitosan derivatives, and synthetic helical polymers) and chiral porous material-based (chiral metal-organic frameworks, chiral covalent organic frameworks, and chiral inorganic mesoporous silicas). Each type of chiral stationary phase is discussed in detail.

Stimuli-Responsive Chiroptical Switching

"Chirality" governs many fundamental properties in chemistry and biochemistry. While early investigations on stereochemistry are primarily dedicated to static chirality, there is an increasing interest in the field of dynamic chirality (chiral switches). These chiral switches are essential in controlling the directionality in molecular motors. Dynamic chiralities are equally crucial in switchable stereoselectivity, switchable asymmetric catalysis and enantioselective separation. Herein, we limit our discussion to recent advances on stimuli-induced chiroptical switching of axial, helical, and planar chirality in response to external stimuli. We also discuss a few examples of applications of the switchable chirality.

Polysaccharides as separation media for the separation of proteins, peptides and stereoisomers of amino acids

Reliable separation of peptides, amino acids and proteins as accurate as possible with the maximum conformation and biological activity is crucial and essential for drug discovery. Polysaccharide, as one of the most abundant natural biopolymers with optical activity on earth, is easy to be functionalized due to lots of hydroxyl groups on glucose units. Over the last few decades, polysaccharide derivatives are gradually employed as effective separation media. The highly-ordered helical structure contributes to complex, diverse molecular recognition ability, allowing polysaccharide derivatives to selectively interact with different analytes. This article reviews the development, application and prospects of polysaccharides as separation media in the separation of proteins, peptides and amino acids in recent years. The chiral molecules mechanism, advantages, limitations, development status and challenges faced by polysaccharides as separation media in molecular recognition are summarized. Meanwhile, the direction of its continued development and future prospects are also discussed.

Protected amino acids as a nonbonding source of chirality in induction of single-handed screw-sense to helical macromolecular catalysts

Chiral nonbonding interaction with N-protected amino acid methyl esters used as chiral additives in achiral solvents allows dynamic induction of single-handed helical conformation in poly(quinoxaline-2,3-diyl)s (PQX) bearing only achiral substituents. Ac-l-Pro-OMe, for instance, allows induction of energy preference of 0.16 kJ mol-1 per monomer unit for the M-helical structure over the P-helix in t-butyl methyl ether (MTBE). With this new mode of screw-sense induction, homochiral screw-sense has been induced in virtually achiral poly(quinoxaline-2,3-diyl)s 1000-mer containing phosphine pendants (PQXphos). Use of PQXphos as a helically dynamic ligand along with Ac-Pro-OMe (l or d) as a chiral additive in MTBE allowed a highly enantioselective Suzuki-Miyaura coupling reaction with up to 95% enantiomeric excess.

Photochemical Electrocyclization of Poly(phenylacetylene)s: Unwinding Helices to Elucidate their 3D Structure in Solution

Photochemical electrocyclization of poly(phenylacetylene)s (PPAs) is used for the structural elucidation of a polyene backbone. This method not only allows classification of PPAs in cis-cisoidal (ω₁ <90°) or cis-transoidal structures (ω₁ >90°), but also approximating ω₁ . A PPA solution is illuminated with visible light and monitoring the photochemical electrocyclization of the PPA helix by measuring the ECD spectra at different times. PPAs with a cis-cisoidal structure show a reduction of the ECD signal of at least 50 % before 30 min of irradiation, while cis-transoidal helices need much longer time because the transoidal bond must be isomerized. The different cis-cisoidal and cis-transoidal helices require different times to decrease their ECD signal by 50 % (t_1/2 ), depending on the degree of compression or stretching of the helix, establishing a relationship between the secondary structure adopted by PPA (ω₁ ) and the time required to lose the ECD vinylic signal by light irradiation.

Synthesis of Stereoregular Telechelic Poly(phenylacetylene)s: Facile Terminal Chain-End Functionalization of Poly(phenylacetylene)s by Terminative Coupling with Acrylates and Acrylamides in Rhodium-Catalyzed Living Polymerization of Phenylacetylenes

Various α,β-unsaturated carbonyl compounds, such as acrylates and acrylamides, were quantitatively introduced to the terminal chain end of poly(phenylacetylene)s by C-C bond formation with terminal organorhodium(I) species formed in the living polymerization of phenylacetylenes with a rhodium-based multicomponent catalytic system that we have recently developed, when these carbonyl compounds were used as terminating reagents. This enables the facile and versatile synthesis of stereoregular telechelic poly(phenylacetylene)s with various functional groups at both the initial and terminal chain ends because the components of aryl boronic acid derivatives used as initiators in our multicomponent catalytic system are quantitatively introduced to the initiating end of the resulting polymer.

Racemic Monomer-Based One-Handed Helical Polymer Recognizes Enantiomers through Auto-Evolution of Its Helical Handedness Excess

A racemic monomer-based optically inactive polyacetylene folds into a one-handed helix assisted by a nonracemic alcohol, which can separate various enantiomers as a chiral stationary phase in chromatography. The chiral-resolving power is virtually identical to that of the enantiopure monomer-based one-handed helical polyacetylene. Because of its unique static memory of the induced helicity, the original racemic polyacetylene expresses an auto-evolution of its helical handedness over time, and at the same time, chirality of the nonracemic alcohol is discriminated accompanied by successive enhancement of its optical purity enantioselectively adsorbed on the helical polyacetylene owing to the chiral filter effect as directly monitored by NMR, which contributes to further enhancing the helix-sense-excess of the helical polyacetylene.

Enantioseparation by high-performance liquid chromatography on proline-derived helical polyacetylenes

The nature, size, and position of the substituent on the phenyl ring remarkably influence the enantioseparation performance of polyacetylene-based CSPs.

Helical polymer self-assembly and chiral nanostructure formation

This review surveys recent progress towards robust chiral nanostructure fabrication techniques using synthetic helical polymers, the unique inferred properties that these materials possess, and their intricate connection to natural, biological chirality.

Advances of enantioselective solid membranes

Rosy prospects of chiral membranes are proposed with novel and robust materials.