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The photorefractive effect in photoconductive ferroelectric liquid crystals that contain photoconductive chiral compounds was investigated. Ter-thiophene compounds with chiral structures were chosen as the photoconductive chiral compounds, and they were mixed with an achiral smectic C liquid crystal. The mixtures exhibit the ferroelectric chiral smectic C phase. The photorefractivity of the mixtures was investigated by two-beam coupling experiments. It was found that the ferroelectric liquid crystals containing the photoconductive chiral compound exhibit a large gain coefficient of over 1200 cm-1 and a fast response time of 1 ms. Real-time dynamic amplification of an optical image signal of over 30 fps using the photorefractive ferroelectric liquid crystal was demonstrated. [ABSTRACT FROM AUTHOR]

Various fascinating optical characteristics in organisms encourage scientists to develop biomimetic synthesis strategies and mimic their unique microstructure. Inspired by the Chameleon's skin with tunable color and superior flexibility, this work designs the evaporated‐induced self‐assembly technique to synthesize the chiral photonic crystal film. Ultrasonic‐intensified and additive‐assisted techniques synergistically optimize the film properties, on the aspects of optic and mechanic. The film shows considerable rigidity and superior flexibility, which can undergo multiple mechanical deformations. Without destroying the chiral nematic structure, the ultimate strain approaches 50%, which exceeds most cellulose‐derived film materials. It also integrates excellent optical performance. The film color can cover the total visible region by tuning the photonic bandgap and has angle‐dependent properties. It can make the response to humidity and solvents, and chromaticity variation reflects the degree of stimulation. Importantly, this structural‐dependent color change is reversible. Lastly, the photonic crystal materials with excellent mechanics and unique optics have been applied in the security. The anti‐counterfeiting material design contains photonic crystal ink, repeatable writing paper, information‐hiding film, and color‐changing labels, with the features of environmentally friendly, economical, non‐destructive, and convenient for authentication. [ABSTRACT FROM AUTHOR]

Front cover: In establishing the left‐right axis of the body in Drosophila, a torsion‐like deformation of the cell occurs (cell chirality). Two myosin Is, Myo1D and Myo1C, are thought to be involved in this process, producing right‐handed and left‐handed cell chirality, respectively. A paper published in the May issue of this journal (Utsunomiya et al. (2024) Genes Cells 29: 380‐396, DOI: 10.1111/gtc.13110) reported that when these myosin Is were expressed in macrophages to observe their interactions with the membrane at the single‐molecule level, Myo1D exhibited mobility consistent with free diffusion, whereas Myo1C showed notably lower mobility. This picture, depicting two vortices in a strait, aptly illustrates their differences. Compared to the fast currents that produce the right‐handed vortex in the back, the currents of the left‐handed vortex in the foreground are docile. Designed by TRAIS Co., Ltd. (Kobe, Japan). [ABSTRACT FROM AUTHOR]

In a paper addressing the problem that the majority of chiral compounds crystallize as racemates instead of conglomerates, Jack Dunitz coined the expression 'Wallach's Rule'. The paper gives credit to Wallach's publication in Liebigs Annalen der Chemie in 1895, in which, among other work, a comparison of crystal density of racemates and their homochiral analogues was reported. Of the nine compounds investigated, eight showed higher densities for the racemates. Although Wallach was the only author of the Annalen paper, it was not Otto Wallach, but Theodore Liebisch, Wallach's colleague from the mineralogy institute in Göttingen at that time, who performed the experiments and reported these results. Short overviews about the CVs of the contemporaries Wallach and Liebisch, as well as Liebisch's postdoc Sommerfeld, are presented. It is discussed whether Wallach or Liebisch had the idea to study crystal densities and which one of the two scientists should be properly credited with proposing 'Wallach′s Rule'. [ABSTRACT FROM AUTHOR]

An elliptical chiral split‐ring‐resonator‐based bilayer thin metasurface is introduced in this paper. The proposed metasurface realizes strong electromagnetic (EM) activity with asymmetric transmission in the K‐band of the microwave regime. The efficiency is more than 80% over a range of frequencies from 18.6 to 20.8 GHz. Angular stability up to 60° makes the structure robust for practical applications. The structure also exhibits a negative refractive index for circularly polarized wave due to the strong chirality factor. Polarization azimuth rotation angle of 90° and ellipticity of 0° reveal the pure EM/optical activity. Furthermore, the simulation and measured results also affirmed orthogonal pure linear polarization transformation. The proposed chiral metasurface finds applications in radar and satellite belonging to K‐band. [ABSTRACT FROM AUTHOR]

Comprehensive Summary: The 21st century has witnessed a continuous evolution in the development of boron‐stereogenic chemistry. Since the 1990s, various innovations for the synthesis of tetracoordinate boron‐stereogenic compounds, which exhibited great potential applications, have been demonstrated by synthetic chemists. This paper reviews the significant progress and recent advances towards the assembly of enantioenriched boron‐stereogenic compounds, and hopes to shed light on new perspectives and inspire further research in this emerging field. [ABSTRACT FROM AUTHOR]

Protein misfolding and amyloid formation are implicated in the protein dysfunction, but the underlying mechanism remains to be clarified due to the lack of effective tools for detecting the transient intermediates. Sum frequency generation vibrational spectroscopy (SFG‐VS) has emerged as a powerful tool for identifying the structure and dynamics of proteins at the interfaces. In this review, we summarize recent SFG‐VS studies on the structure and dynamics of membrane‐bound proteins during misfolding processes. This paper first introduces the methods for determining the secondary structure of interfacial proteins: combining chiral and achiral spectra of amide A and amide I bands and combining amide I, amide II, and amide III spectral features. To demonstrate the ability of SFG‐VS in investigating the interfacial protein misfolding and amyloid formation, studies on the interactions between different peptides/proteins (islet amyloid polypeptide, amyloid β, prion protein, fused in sarcoma protein, hen egg‐white lysozyme, fusing fusion peptide, class I hydrophobin SC3 and class II hydrophobin HFBI) and surfaces such as lipid membranes are discussed. These molecular‐level studies revealed that SFG‐VS can provide a unique understanding of the mechanism of interfacial protein misfolding and amyloid formation in real time, in situ and without any exogenous labeling. [ABSTRACT FROM AUTHOR]

Chiroptical response, demonstrating chiral interaction between optical vortex and chiral structure, plays an important role in variety of fields like optics and material science. However, the flexibility and efficiency of chiral structure fabrication are limited due to mask requirement and a point‐by‐point constructing strategy. In this paper, a novel chiral lithography method is proposed that utilizes optical vortex phase beam shaping to achieve chiral structure processing with high efficiency and flexibility. By programming topological charges of the vortex phase, chiral structures with adjustable appearance, rotation, and chirality can be produced using femtosecond laser single pulse exposure. Transmittance measurements of fabricated chiral structures array confirm a 66% helical dichroism that is predicted by simulation. Moreover, with the aid of convolutional neural networks (CNN), an accuracy of 98% in Orbital Angular Momentum (OAM) recognition can be achieved. This chiral lithography method provides an alternative for chiral structure fabrication and holds promise in the development of chiral optics, optical communications, and next‐generation optical devices. [ABSTRACT FROM AUTHOR]

Fundamental studies of the interaction of chiral light with chiral matter are important for the development of techniques that allow handedness‐selective optical detection of chiral organic molecules. One approach to achieve this goal is the creation of a Fabry–Pérot cavity that supports eigenmodes with a desired electromagnetic handedness. This paper theoretically studies chiral Fabry–Pérot cavities with mirrors comprising 1D photonic crystal slabs made of van der Waals As2S3, a material with one of the highest known in‐plane anisotropies. By utilizing the anisotropy provided by As2S3, Fabry–Pérot cavities with constitutional and configurational chiralities are designed. It is demonstrated that in cavities with constitutional chirality, electromagnetic modes of left or right handedness exist due to the chirality of both mirrors, often referred to as handedness preserving mirrors in the literature. At the same time, cavities with configurational chirality support modes of both handednesses due to the chiral morphology of the entire structure, set by the twist angle between the optical axes of the upper and lower non‐chiral anisotropic mirrors. The developed chiral Fabry–Pérot cavities can be tuned to any distance between the mirrors by properly twisting them, making such systems a prospective platform for the coupling of chiral light with chiral matter. [ABSTRACT FROM AUTHOR]

In this paper, an ultra‐wideband chirality selective metastructure absorber is proposed that enables differential absorption and reflection of circularly polarized waves in the terahertz (THz) range. The structure achieves circular dichroism (CD) by using asymmetrically split metal rings as fundamental meta‐atoms. Most critically, the high impedance surface and air‐resonant cavities are inserted separately in the meta‐atoms and dielectric substrate to enhance CD and broaden the bandwidth of absorption. The metastructure absorber can achieve more than 90% absorption of right circularly polarized waves at 0.675–1.244 THz, and it can maintain more than 90% reflection of left circularly polarized waves at 0.607–1.229 THz without changing the direction of rotation. Besides, its CD can reach more than 80% at 0.687–1.213 THz with a relative bandwidth of 55.3%. Spin‐selective absorption, which is closely related to breaking chiral symmetry, is investigated through power loss distribution, wide‐angle incidence, and scan parameter optimization. The proposed strategy is further validated in the THz band, and the polarization selection and manipulation techniques can be applied to chiral sensing/radio‐thermometry, circular polarization detectors/lasers, and molecular spectroscopy. [ABSTRACT FROM AUTHOR]

Recently, the application of magnetic fields to chiral chemical systems has been rewarding. In a forward‐looking 1986 paper, 'Chiral Metals?', Wallis, Karrer, and Jack D. Dunitz forecast 'that the limitation to proper symmetry elements in a chiral conductor could be associated with the emergence of new properties, those connected with interactions between applied electric and magnetic fields and their internal counterparts.' This was a prescient remark, but it has become manifest in ways that would not have been foreseen in its details by the authors. Here are reviewed the development of chiral conductors broadly imagined by Dunitz and coworkers, based on enantiopure tetrathiafulvalene derivatives that restrict space groups to those that have only symmetry operations of the first kind, as well as the new emergent properties associated with the transport of electrons when magnetic fields are applied to chiral crystals among other systems. These include electrical magnetochiral anisotropy (eMChA), inverse electrical magnetochiral anisotropy (ieMChA), helimagnetism and chirality induced spin selectivity (CISS). The conclusion discussing the circumstances under which achiral TTF crystals becomes chiral, only seems to introduce an oxymoron. [ABSTRACT FROM AUTHOR]

The recently discovered ferroelectric nematic (NF) liquid crystals (LCs) with over 0.04 C m−2 ferroelectric polarization and 104 relative dielectric constants, coupled with sub‐millisecond switching, offer potential applications in high‐power super capacitors and low voltage driven fast electro‐optical devices. This paper presents electrical, optical, and electro‐optical studies of a ferroelectric nematic LC material doped with commercially available chiral dopants. While the NF phase of the undoped LC is only monotropic, the chiral NF phase is enantiotropic, indicating a chirality induced stabilization of the polar nematic order. Compared to undoped NF material, a remarkable improvement of the electro‐optical switching time is demonstrated in the chiral doped materials. The color of the chiral mixtures that exhibit a selective reflection of visible light in the chiral NF phase, can be reversibly tuned by 0.02–0.1 V µm−1 in‐plane electric fields, which are much smaller than typically required in full‐color cholesteric LC displays and do not require complicated driving scheme. The fast switchable reflection color at low fields has potential applications for LC displays without backlight, smart windows, shutters, and e‐papers. [ABSTRACT FROM AUTHOR]

The use of hierarchically structured materials as catalysts has been finding increasing application in the past years. For these catalytic systems, not only the nano‐scale matters: a high degree of order across multiple length scales, along with its control and analytical assessment, is of paramount importance to obtain innovative properties that can find application in catalysis. Most reviews dealing with hierarchically structured materials are concerned with the "bottom‐up" transfer of structural information along the different length scales, with special emphasis on the transmission of chirality. Due to their mesoscale size together with their complex behaviour, these systems are often susceptible to feel the effects of macroscopic forces, that can exert a "top‐down" control of their catalytic properties, so that an external stimulus, acting at the level of the supramolecular architecture of the catalyst, can ultimately determine the outcome of the catalyzed reaction at the molecular level. We review in this paper some recent reports that deal with the experimental implementation of this concept, either by using a mechanical force in a full range direct transmission to the reaction coordinate, or by means of a stepwise relay transmission from the macroscopic level (purely supramolecular chirality) to the nanoscopic one. We focus in this review on these multi‐length scale communication control effects, identifying the different mechanisms that are affecting the catalytic activity. [ABSTRACT FROM AUTHOR]

The reaction of trans‐[Pt(DMSO)2MeCl] with 2‐alkylsubstituted pyridines pyR affords a series of complexes of the type [Pt(pyR)(DMSO)MeCl]. These complexes are rare examples of organometallic square‐planar complexes having four different ligands. Of the three possible geometric isomers, only the trans(N,S)‐[Pt(pyR)(DMSO)MeCl] was observed in solution and isolated in the solid state. However, the lack of chirality typical to square planar geometry can be resolved in several ways one of which is described in this paper. 1H NMR studies reveal diastereotopicity of the DMSO methyls, as well as the CH2 protons in the ethyl‐ and neopentyl‐pyridine complexes and the methyls in the isopropyl‐pyridine derivative. This observation can be ascribed to restricted rotations around the Pt−N bond, thus resulting in the presence of planar chirality for these complexes. Additionally, large downfield shifts in the 1H NMR spectra of the α C−H protons in the pyridine substituents suggested the presence of Pt⋯H−C interactions, confirmed via single crystal X‐ray studies in the case of the isopropyl complex [Pt(pyip)(DMSO)MeCl] (4), which shows an apical Pt⋯H interaction with a short 2.585 Å distance. DFT calculations shed light into the stability of these complexes and the influence of the pyridine‐substituent on their chiral configuration. [ABSTRACT FROM AUTHOR]

This paper presents an all‐dielectric chiral metasurface composed of an array of two‐layer distorted square structures with nanoholes. This metasurface can simultaneously generate dual‐band opposite chiral responses, which can be attributed to the bound states in the continuum (BICs) and the distorted chiral structure. By combining the BICs with chirality, a dual‐band chiral nonlinear metasurface and a chiral‐sensing method are proposed. The simulated results show that the third harmonic generation (THG) conversion efficiency can reach the order of 10−4 for two peaks with a peak‐pump intensity of approximately 5.3 GW cm−2 in the near‐infrared region. Moreover, the third‐harmonic circular dichroism for each peak can reach up to 0.99 and ‐0.94, respectively. Furthermore, it is theoretically demonstrated that this metasurface can be used for chiral sensing with high sensitivities. These results provide new insights for linear and nonlinear spin‐dependent applications. [ABSTRACT FROM AUTHOR]

Based on a CSD search, a meta‐analysis of 1179 structures of 19 natural amino acids H3NCαH(R)C′(O)O and their derivatives H3NCαH(R)C′(O)O(H/R/M), protonated, esterified, or coordinated at the carboxylic group, shows that the chirality chain with its two steps, established in the preceding paper for alanine, can be extended to natural amino acids. High diastereoselectivities are observed in the induction from the L configuration at Cα to the −ψ and +ψ conformations, which in turn distort the planar carboxylic group CαC′(Ocis)Otrans to asymmetric flat tetrahedra, showing that the chirality chain is an integral part of natural amino acids. [ABSTRACT FROM AUTHOR]

Supramolecular structures of organic molecules on planar nanocarbon surfaces, such as highly oriented pyrolytic graphite (HOPG), have been extensively studied and the factors that control them are generally well‐established. In contrast, the properties of supramolecular structures on curved nanocarbon surfaces like carbon nanotubes remain challenging to predict and/or to understand. This paper reports an investigation into the first study of the supramolecular structures of 5,15‐bisdodecylporphyrin (C12P) on chiral, concentrated single‐walled carbon nanotubes (SWNTs; with right‐handed helix P‐ and left‐handed helix M‐) surfaces using STM. Furthermore, the study is the first of its kind to experimentally assign the absolute‐handedness chirality of SWNTs, as well as to understand their effect on the supramolecular structures of organic molecules on their surfaces. Interestingly, these SWNT enantiomers resulted in supramolecular structures of opposite chirality based on the handedness chirality. With molecular modelling, we predicted the absolute‐handedness chirality of SWNTs, before demonstrating this experimentally. By using the STM imaging technique, the single‐walled carbon nanotube (SWNT) absolute‐handedness of chirality has been experimentally investigated using supramolecular structures of porphyrin derivatives (C12P). Two opposite chiral supramolecular structures have been observed based on the SWNT enantiomers handedness of chirality (see figure). [ABSTRACT FROM AUTHOR]

Chirality has become an important research subject. The research areas associated with chirality are under substantial development. Meanwhile, graphene is a rapidly growing star material and has hard‐wired into diverse disciplines. Rational combination of graphene and chirality undoubtedly creates unprecedented functional materials and may also lead to great findings. This hypothesis has been clearly justified by the sizable number of studies. Unfortunately, there has not been any previous review paper summarizing the scattered studies and advancements on this topic so far. This overview paper attempts to review the progress made in chiral materials developed from graphene and their derivatives, with the hope of providing a systemic knowledge about the construction of chiral graphenes and chiral applications thereof. Recently emerging directions, existing challenges, and future perspectives are also presented. It is hoped this paper will arouse more interest and promote further faster progress in these significant research areas. [ABSTRACT FROM AUTHOR]

Deep understanding of structure–property relationship between packing of chiral building units and their chiroptical behaviors would significantly facilitate the rational design and fabrication of the emerging chiroptical materials such as circularly polarized luminescence (CPL) emissive materials. In this paper, we unveil the universal existence of supramolecular tilt helical superstructures in self‐assembled π‐conjugated amino acid derivatives. A series of coded amino acid methyl esters were conjugated to anthracene segments at N‐terminus, which afforded 21 and 31 symmetry supramolecular tilt chirality in solid‐states. Helical assemblies enabled diversified Cotton effects and CPL performances, which were in accordance with the tilted chirality between anthracene segments. Such correlation shows fine universality, whereby the chiroptical prediction could be realized. Furthermore, on top of charge‐transfer complexation, manipulation of CPL emission colors and handedness were realized. [ABSTRACT FROM AUTHOR]

This paper describes the syntheses of [2]rotaxanes comprising 23‐ and 26‐membered biphenyl crown ethers as the macrocyclic components and secondary ammonium ions as the dumbbell‐shaped components, and the locking of the dynamic axial chirality of the biphenyl moieties in these structures. Chiral high‐performance liquid chromatography (HPLC) revealed that our [2]rotaxane featuring the 26‐membered crown ether racemized at room temperature, but the racemization of the [2]rotaxane featuring the 23‐membered crown ether did not proceed at room temperature over a period of three days. After separation of the enantiomers of the [2]rotaxane incorporating the 23‐membered crown ether through chiral HPLC, we studied its racemization at elevated temperature. The rate of stereoinversion in dimethylsulfoxide (a polar solvent) was faster than that in o‐dichlorobenzene (a nonpolar solvent), and herein we discuss these kinetic parameters. [ABSTRACT FROM AUTHOR]

In common with other hindered structures containing two aromatic rings linked by a short tether, diarylamines may exhibit atropisomerism (chirality due to restricted rotation). Previous examples have principally been tertiary amines, especially those with cyclic scaffolds. Little is known of the structural requirement for atropisomerism in structurally simpler secondary and acyclic diarylamines. In this paper we describe a systematic study of a series of acyclic secondary diarylamines, and we quantify the degree of steric hindrance in the ortho positions that is required for atropisomerism to result. Through a detailed experimental and computational analysis, the role of each ortho‐substituent on the mechanism and rate of conformational interconversion is rationalised. We also present a simple predictive model for the design of configurationally stable secondary diarylamines. [ABSTRACT FROM AUTHOR]

Supramolecular capsules can be used to change the activity and selectivity of a catalyst through the influence of the second coordination sphere, reminiscent of how enzymes control the selectivity of their processes. In enzymes, this approach is used to also control the enantioselectivity of reactions in which the active catalytic site is often not chiral but the second coordination sphere is. We are interested in the possibility to generate a chiral second coordination sphere around an otherwise achiral transition metal complex for asymmetric catalysis. In this paper we show that the ligand template approach can be used to generate a chiral second coordination sphere around a rhodium complex, which is used in asymmetric hydroformylation. [ABSTRACT FROM AUTHOR]

The detection and separation of medetomidine enantiomers from the complex biological matrices poses a great analytical challenge, especially in the field of forensic toxicology and pharmacology. Couple of researchers reported resolution of medetomidine using protein‐based chiral columns, but the reported method is quiet challenging and tedious to be employed for routine analysis. This research paper reported a method that enables the enantio‐separation of medetomidine by using polysaccharide cellulose chiral column. The use of chiralcel OJ‐3R column was found to have the highest potential for successful chiral resolution. Ammonium hydrogen carbonate was the ideal buffer salt for chiral liquid chromatography (LC) with electrospray ionization (ESI)+ mass spectrometry (MS) detection for the successful separation and detection of racemic compound. The method was linear over the range of 0 to 20 ng/mL in equine plasma and the inter‐day precisions of levomedetomidine, dexmedetomidine were 1.36% and 1.89%, respectively. The accuracy of levomedetomidine was in the range of 99.25% to 101.57% and that for dexmedetomidine was 99.17% to 100.99%. The limits of quantification for both isomers were 0.2 ng/mL. Recovery and matrix effect on the analytes were also evaluated. Under the optimized conditions, the validated method can be adapted for the identification and resolution of the medetomidine enantiomers in different matrices used for drug testing and analysis. [ABSTRACT FROM AUTHOR]

CNFET devices are preferred over CMOS devices for designing high‐speed digital circuits. This paper introduces a new technique Dual Chirality High‐speed Domino Logic (DCHSDL) for implementing low power and high‐speed domino circuits in CNFET technology. Simulations are carried out for 32 nm Stanford CNFET model in HSPICE for 2, 4, 8 and 16 input domino OR gates at a clock frequency of 200 MHz on a DC supply voltage of 0.9 V. The proposed domino technique shows maximum power reduction of 82.55% and maximum delay reduction of 57.97% compared to CPVT technique in CNFET technology at a frequency of 200 MHz. The proposed circuit shows maximum power reduction of 97.90% compared to its analogous circuit in CMOS technology for a 2‐input domino OR gate. The proposed technique shows maximum improvement of 1.05× to 1.63× in unity noise gain (UNG) compared to various existing techniques in CNFET technology at a frequency of 200 MHz. The 1‐bit Full Adder designed using the proposed technique shows a power reduction of 16.91% and a delay reduction of 23.64% compared to standard FDL 1‐bit Full Adder. [ABSTRACT FROM AUTHOR]

This paper describes the first diastereoselective synthesis of cyclic α‐aminophosphonic and α‐amino phosphonic acids from glycyl‐l‐proline 2,5‐diketopiperazine (S)‐6 prepared according to the usual peptide coupling procedures. The highlights of this contribution is the chemoselective reduction of the carbamate‐imide activated carbonyl group in the N‐Boc 2,5‐diketopiperazine (S)‐11 to generate the unstable hemiaminals (1R,8aS)‐12 and (1S,8aS)‐13, followed by the highly diastereoselective nucleophilic addition of trimethyl phosphite or dimethyl phenylphosphonite to the chiral carbenium ion (S)‐5. Acid hydrolysis of the phosphonate and phosphinate functionalities with simultaneous cleavage of the tert‐butyl carbamate protecting group led to the target compounds. The high diastereoselectivity in the nucleophilic addition of trivalent phosphorus to the chiral carbenium ion (S)‐5 is in agreement with our precedent reports. [ABSTRACT FROM AUTHOR]

Carbon‐based nanomaterials have catalyzed breakthroughs across various scientific and engineering disciplines. The key to unlocking a new generation of tailor‐made nanomaterials based on single‐walled carbon nanotubes (SWCNTs) lies in the precise sorting of raw material into individual chiralities, each possessing unique properties. This can be achieved using conjugated polymer extraction (CPE), but to a very limited extent since the process generates only a few chirality‐enriched suspensions. Therefore, it is imperative to comprehend the mechanism of the wrapping of SWCNTs by polymers to unleash CPE's full potential. However, the lack of a diverse palette of chirality‐selective polymers with varying macromolecular parameters has hindered a comprehensive understanding of how the nature of the polymer affects the performance and selectivity of SWCNT isolation. To address this gap, multiple batches of such polymers are synthesized to elucidate the impact of molecular weight and dispersity on the purity and concentrations of the generated SWCNT suspensions. The obtained results explain the inconsistent outcomes reported in the literature, greatly improving the application potential of this promising SWCNT sorting approach. Concomitantly, the discovered significant influence of the macromolecular characteristics of conjugated polymers on the SWCNT isolation efficacy sheds considerable insight into the unresolved mechanism of this sorting technique. [ABSTRACT FROM AUTHOR]

The conceptual difference between the chiral and nonreciprocal magnetoelectric effects is clarified in the present communication. The conclusions bear a strong effect on the message of a recent paper by Krowne in this journal. © 1998 John Wiley & Sons, Inc. Microwave Opt Technol Lett 18: 312–314, 1998. [ABSTRACT FROM AUTHOR]

Two independent statistical models for evaluating the certainties of configurational assignments of compounds based on nuclear magnetic resonance (NMR) data are evaluated and compared. Both methods yield weights or probabilities with which two or more structure models (constitutional or configurational isomers or even conformers) could be differentiated based on experimental parameters. Although this paper focusses on the use of residual dipolar couplings (RDCs) for the differentiation of diastereomers, the concept can be expanded to any set of experimental NMR‐derived parameters. It is demonstrated that highly reliable configurational assignments crucially must depend on thorough statistical analysis, which is frequently neglected in the literature. [ABSTRACT FROM AUTHOR]

This paper describes the synthesis and characterization of 21 chiral monodentate ligands L, assembled of three building blocks utilizing amide bonds: a metal binding triphenylphosphine, a chiral cyclic diamine and an additional substituent for fine‐tuning the steric and/or electronic properties. Cis square‐planar metal complexes of RhI and PtII with ML2 stoichiometry have been prepared and characterized by spectroscopic methods (NMR, IR, UV‐Vis, CD) and DFT calculations. A key feature of the metal complexes is a prochiral metal coordination sphere and "backdoor induction" of chirality from a distant chiral source via an outer‐coordination sphere, well‐defined by aromatic stacking and hydrogen‐bonding. The rhodium complexes were used as catalysts in asymmetric hydrogenation of α,β‐dehydroamino acids with excellent yield and selectivity (up to 97 % ee), strongly supporting the "backdoor induction" hypothesis. Chiral information is transmitted from a distant chiral source to the prochiral coordination sphere by means of noncovalent interactions, resulting in up to 97 % ee in asymmetric hydrogenations. [ABSTRACT FROM AUTHOR]

The separation of chiral compounds is an interesting and important topic of research because these compounds are involved in some biological processes, fundamentally in human health. Among the various application fields where enantiomers are remarkable, drug analysis has to be considered. Most of the drugs contain enantiomers and very often one of the two isomers could be pharmacologically more active or even dangerous. Therefore, the separation of these compounds is very important. Among the different analytical techniques usually employed, capillary electrochromatography has demonstrated great capability in enantiomers resolution. The great potential of this electromigration technique stands mainly in its high efficiency due to the use of an electrosmotic flow (flat flow profile) and on the high selectivity because of the use of a stationary phase. Chiral separation can be obtained utilizing several chiral stationary phases including a polysaccharide derivative. The aim of this review paper is to summarize the main features of capillary electrochromatography and polysaccharide derivatives of chiral stationary phase. It also report examples of practical applications utilizing this approach. [ABSTRACT FROM AUTHOR]

The paper moves from a technological process developed in previous works to produce chiral honeycombs made of thin composite laminates. Such approach is applied in this work to manufacture the morphing ribs for a variable camber wing-box. The specifications for such components are obtained by developing a finite element model of a demonstrator, which is designed taking into account aeroelastic performances, structural, and technological issues. In the first part of the paper, the design of such a demonstrator is presented and the role of composite chiral ribs with auxetic behavior is outlined. Production, testing, and numerical studies of manufacturing trials are performed to assess the technological process applied to small-sized chiral units made of different materials, to investigate their mechanical properties, and to validate a numerical approach for design and analysis. A complete chiral composite rib is then produced and tests are carried out to verify the overall structural response and to validate the numerical approach. [ABSTRACT FROM AUTHOR]

Chiral (ILs) have drawn more and more attention in separation science; however, only a few papers focused on the application of chiral ILs as chiral ligands in LE-CE. In this article, a novel amino acid ionic liquid (AAIL), tetramethylammonium L-hydroxyproline ([TMA][L-OH-Pro]), was first applied as a chiral ligand to evaluate its towards several aromatic in ligand-exchange (LE-CE) and ligand-exchange micellar electrokinetic capillary chromatography (LE-MEKC). In the LE-CE system, excellent separations were achieved for tryptophan (Rs = 3.03) and 3, 4-dihydroxyphenylalanine (DOPA) (Rs = 4.35). Several parameters affecting the enantioseparation were systematically investigated, including AAIL concentration, type and concentration of central metal ion, buffer pH, as well as applied voltage. The optimum separation was obtained with 60 mM AAIL containing 30 mM Cu (II) at pH 4.5. Additionally, an LE-MEKC system was established to further study the of [TMA][L-OH-Pro] towards selected analytes. As observed, the separations of the enantiomers of tryptophan, phenylalanine, and histidine were all improved compared to the LE-CE system. The results indicated that the application of AAILs as chiral ligands is a promising method in chiral separation science. Chirality 27:58-63, 2015. © 2014 Wiley Periodicals, Inc. [ABSTRACT FROM AUTHOR]

Chiral polymers and chiral polymeric particles have emerged as a new and exciting field of research in recent years mainly due to their possibly applications in chiral chemistry. This paper reviews the present state of the art regarding production techniques for the synthesis and applications of chiral polymeric particles. The main methods for preparing of chiral polymeric particles such as: direct polymerization, emulsion, precipitation, and suspension polymerization of chiral monomers, are reviewed. Moreover, in this article we also present the use of chiral polymers as chiral templates for the synthesis of chiral mesoporous materials. In this review we highlighted the properties and parameters involved in the preparation of these chiral polymeric materials. The present review focuses mainly on the use of chiral polymer and chiral polymeric particles for enantioselective crystallization and enantioseparation. References of the most relevant literature published by various research groups are provided. Anyway, it is clear that chiral polymeric particles are a distinctive type of chiral nanomaterials that can find many new application in other fields like, chiral drug delivery systems, enantioselective catalysis. We hope that this review article will inspired new researchers in this field and will boost the research dealing on chiral polymeric particles especially in their implementation in new areas in chiral chemistry. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the peculiar co‐assembly supramolecular polymerization behavior of triphenylamine trisamide derivatives with d‐alanine (T‐ala) or glycine (T‐gly) moieties. Concentration and temperature‐dependent circular dichroism (CD) spectroscopy revealed that the heating curves of co‐assemblies obtained at various molar ratios of T‐ala to T‐gly exhibited two distinct transition temperatures. The first transition was due to the transformation from coiled helical bundles to single helical fibers without handedness. The second was due to a change from typical elongation to nucleation. These phenomena were confirmed by solvent‐dependent decoiling of coiled helical structures and concentration‐dependent morphological analysis. The two transitioning temperatures were dependent on the concentration of T‐ala in the co‐assemblies, suggesting that T‐ala concentration plays an important role in the formation of coiled helical bundles. Our study demonstrated the first observation of two distinct transition temperatures in supramolecular polymers. [ABSTRACT FROM AUTHOR]

SUMMARY Because the permittivity, permeability, and chirality parameters of chiral metamaterials (CMMs) are frequency dependent, the wave equations that describe the characters of electromagnetic wave propagation in CMMs are presented and discretized on the basis of auxiliary differential equation technique in finite-difference time-domain method. The total-field/scattered-field, Mur's first-order absorbing and dielectric boundary conditions for CMMs slab are discussed in the paper. Numerical results show that the cross-polarized reflected coefficient of the CMMs slab is zero. Negative index of refraction phenomenon and optical property of giant optical activity in CMMs slabs are illustrated with 1D auxiliary differential equation-finite-difference time-domain method. The effects to positive or negative phase velocity caused by media parameters of CMMs are studied. Copyright © 2013 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

This paper extends the concept of entangled vector vortex beams as a form of Majorana‐like photons. Majorana photon quasi particles are introduced and attributed to a class of entangled vector beams and show higher transmission. These photons and the antiphotons are identical. A Majorana photon has within itself both right and left handed twists. These majorana beams travel at speeds other than speed of light, c in free space. Light transmission of Majorana photon vortex beams with orbital angular momentum (OAM) are investigated in a mouse brain at different local regions showing enhanced transmission and properties of being entangled. This work is new interpretation of our past paper of mixed photon beam states. The transmission change observed with Majorana structured light other than linear polarization is attributed to the nonseparable and mixed nature of radial and azimuthal polarizations with OAM and the handedness of the light passing through chiral brain media. These mixed nonhomogeneous beams are entangled in OAM and polarization. Majorana photons may play an important role in the future for quantum and optical computing and sub and super luminal speeds due to its traversal wave vector, k. [ABSTRACT FROM AUTHOR]

In this paper, we have studied the chiroptical properties of a family of o-oligo(phenyleneethynylene) ( o-OPE) derivatives with different steric hindrance. Experimental results show high dissymmetry factors (gabs and glum up to 1.1 × 10−2) and very similar electronic circular dichroism (ECD) and circularly polarized luminescence (CPL) for all the derivatives that make this basic o-OPE scaffold a robust pure organic emitter. Vibrational circular dichroism spectra are used to characterize conformational properties in solution. Density functional theory and time-dependent density functional theory calculations support experimental results also proving that ECD and CPL are almost exclusively linked to helical moiety and not to size or conformation of substituents. As chiroptical properties of these emitters are independent of substituents, this OPE scaffold can be used as basic skeleton for the design of sensing probes with high CPL efficiencies. [ABSTRACT FROM AUTHOR]

Chiral nematic mesoporous organosilica (CNMO) films are functionalized with a mixture of hydrophobic silanes and spiropyran compounds to create freestanding photochromic films that can be used for reversible photo­patterning. The mesoporosity and interconnected pore structure of the films imparted by the cellulose nanocrystal template enables a large cross-section of the material to be functionalized. Thus, the materials show intense absorption spectra from the tethered spiropyran and rapid color changes when the porous films are irradiated with UV or white light. The spiropyran-bound CNMO films behave as reversible sensors where metal binding to the spiropyran results in visible color changes detectable by the naked eye. These metals can be removed in the presence of ethanol and white light, regenerating the metal-free film. The proof-of-concept demonstrated in this paper may help to develop new photochromic displays, security features, and patterns. [ABSTRACT FROM AUTHOR]

Choosing the optimal catalyst for a new transformation is challenging because the ideal molecular requirements of the catalyst for one reaction do not always simply translate to another. Large groups at the 3,3′ positions of the binaphthol rings are important for efficient stereoinduction but if they are too large this can lead to unusual or poor results. By applying a quantitative steric assessment of the substituents at the 3,3′ positions of the binaphthol ring, we have systematically studied the effect of modulating this group on enantioselectivity for a wide range of reactions involving imines, and verified this analysis using ONIOM calculations. We have shown that in most reactions, the stereochemical outcome depends on both proximal and remote sterics. Summarising detailed calculations into a simple qualitative model identifies and explains the steric features required for high selectivity. This model is consistent with seventy seven papers reporting reactions (over 1000 transformations in total), and provides a straightforward decision tree for selecting the best catalyst. [ABSTRACT FROM AUTHOR]

Carbon nanotubes (CNTs) are of interest in various industries owing to their high aspect ratio, electrical conductivity, and other properties. By maximizing the number of CNTs in their solvents or matrices, the electrical and mechanical performance in applications such as batteries, sensors, and transistors can be enhanced. However, the hydrophobicity of CNTs' surface induces aggregation that adversely impacts their performance. To overcome this obstacle, many researchers have been designing novel dispersants with performances exceeding that of existing commercial dispersants. This article reviews contemporary studies on CNT dispersants from 2015 to 2022, along with the comprehensive features of CNTs depending on their chirality, number of walls, synthesis methods, and functionalization. Studies of CNT dispersants are primarily organized according to whether aqueous or organic solvents are used. This review article provides a clear perspective of CNT dispersants development today and how to design new CNT dispersants depending on the solvents. A conclusion is given to identify major challenges to the implementation of CNT dispersion and an outlook on future avenues of research. [ABSTRACT FROM AUTHOR]

With the adsorption of larger molecules being increasingly tackled by surface scientists, the aspect of chirality often plays a role. This paper gives a topical review of molecular chirality at surfaces and gives a phenomenological overview of different aspects of adsorption and self-assembly of chiral and prochiral molecules and the principles of mirror-symmetry breaking at a surface. After a brief introduction into the history of molecular chirality and the important role it played for understanding the spatial structure of molecules, definitions of chirality are presented. Topics treated here are principle ways to create single chiral adsorbates, chiral ensembles, and monolayers by achiral molecules, adsorption of intrinsically chiral molecules at achiral and chiral surfaces, long-range symmetry breaking in two-dimensional (2D) crystals due to additional chiral bias, chiral restructuring of solid surfaces under the influence of chiral molecules, switching the handedness of adsorbates, and chirality at the liquid/air interface. An outlook onto further potential research directions and recommendations for further reading, including nonsurface-related sources of chiral topics completes this paper. [ABSTRACT FROM AUTHOR]

Given a small number of structure factors of a known chiral structure of unknown hand, it is shown that the hand can be determined from the sign of the contrast difference of two reflections in a suitably oriented convergent-beam electron diffraction (CBED) pattern. A simple formula for this difference, which takes into account all the significant second-order scattering, is derived using the series expansion of Cowley and Moodie for n-beam diffraction. The reason for the success of a three-beam interpretation is investigated. The method is applied to patterns from thin crystals in which a mirror projection symmetry can be found and its validity is demonstrated by agreement with experiment using samples of known hand. The advantages of recording patterns near major zone axes are discussed as well as some other experimental aspects of chiral determination using CBED. [ABSTRACT FROM AUTHOR]

Optically active 1-α-methylbenzyl-3-p-tolylurea (MBTU) shows diverse plant physiological properties. Gramineae plants exhibit enantioselective root growth inhibition byR/S-MBTU. In the present paper, the dose–growth response (DGR) towards the optically active MBTUs was examined in the tribe Triticeae plants, includingHordeum vulgareL.,Secale cerealeL.,Triticum aestivumL. andAegilops cylindricaHost., and compared with those of the genusBromus(B. inermisLeyss), which is classified into the tribe Bromeae, and the genusOryza. In spite of their phylogenetic difference, the Triticeae plants responded homogeneously in their chiral recognition. Of particular interest, is the result of the dichotomic enantioselective response of tested Gramineae plants. Only the genusOryzaresponds toR-MBTU, and the tribes Triticeae (Triticum,Aegilops,SecaleandHordeum) and Bromeae (Bromus) preferentially respond to theS-enantiomer. The tetrazolium–phenazine methosulfate–formazan (TPF) assay was demonstrated to measure redox activity of root tips of the MBTU-treatedOryza sativaandT. aestivum, which are the typical dichotomic, enantioselective-responsive plants. InOryzaandTriticumroot tips, enantioselective responses of reduction activity in TPF assays were strongly related to those of root growth inhibition in DGR assays, suggesting aggressive participation of the MBTU in the generation of the reducing mechanism in mitochondria. [ABSTRACT FROM AUTHOR]

Helical architectures with controllable helical sense bias have recently attracted considerable interest for mimicking biological helices and developing novel chiral materials. Coordination polymers (CPs), composed of metal ion nodes and organic linkers, are intriguing systems showing tunable structures and functions. However, CPs with helical morphologies have rarely been explored so far. Particularly, chirality inversion through external stimulus has not been achieved in helical CPs. In this work, we carried out an in‐depth investigation on the self‐assembly of 1D gadolinium(III) phosphonate CPs using GdX3 (X=Cl, Br, I) and Gd(RSO3) (R=CH3, C6H5, CF3) as metal sources and R‐(1‐phenylethylamino)methyl phosphonic acid (R‐pempH2) as ligand. Superhelices were formed by precise control of the interchain interactions through different intercalated anions. Furthermore, the twisting direction of superhelices could be controlled by synergistic effect of anions and pH. This study may provide a new route to fabricate helical nanostructures of CPs with a desirable chiral sense and help understand the inner mechanism of the self‐assembly process of macroscopic helical structures of molecular systems. [ABSTRACT FROM AUTHOR]

In spite of the many resolution techniques available to separate enantiomers, diastereomeric resolution still remains the most widely used technique in industry. However, drawbacks of this technique are the limited yield of the desired enantiomer and the expensive enantiopure resolving agent that is required. We show here for the first time that a combination of diastereomeric resolution with Viedma ripening using a racemic resolving agent can also provide a single stereoisomer when using an excess of the racemic resolving agent, without the need for the resolving agent to racemize. The requirements of this process are, like for an enantiomeric system, that the compound crystallizes as a racemic conglomerate and that at least one chiral center in the target molecule is racemizable. In addition, owing to the presence of the racemization reaction, substantial improvement in the yield can be obtained. We here demonstrate this approach using a metastable conglomerate salt of rac‐2‐phenylglycinamide with rac‐N‐acetyl tryptophan. [ABSTRACT FROM AUTHOR]

Enantiodivergent one‐pot synthesis of biaryls was developed using a catalytic amount of a single chiral source. A domino organocatalyst‐mediated enantioselective Michael reaction and aldol condensation provided centrally chiral dihydronaphthalenes with excellent enantioselectivity, from which an enantiodivergent chirality conversion from central‐to‐axial chirality was achieved. Both enantiomers of biaryls were obtained with excellent enantioselectivity. All transformations can be conducted in a single reaction vessel. A plausible reaction mechanism for the enantiodivergence is proposed. [ABSTRACT FROM AUTHOR]

This article discloses a study on a chiral bis‐phosphorylated‐helical ligand in the palladium‐catalyzed Tsuji‐Trost allylation. The use of 2,15‐bisphosphinite‐[6]‐helicenes revealed a remarkable ligand effect, in which the (R) and (S) isomeric products can be selectively formed as a direct function of the amount of ligand introduced. Investigation of the organometallic species involved through 31P NMR spectroscopic analysis of a model complex and X‐Ray diffraction analysis together with DFT calculations shed light on this phenomenon. [ABSTRACT FROM AUTHOR]

Tailoring of enzyme toward α‐tetralones, a class of bulky‐bulky ketones, is still a challenge. In this work, the mutants of carbonyl reductase BaSDR1 with improved catalytic performance toward α‐tetralone 1 a were obtained by adjusting the steric hindrance and hydrophobicity of the residues that affect the approach of α‐tetralone with the catalytic residues. The designed mutants also showed enhanced catalytic performance toward halogenated α‐tetralones 2 a–6 a. Remarkably, the activity of the mutant Q237V/I291F toward 7‐fluoro‐α‐tetralone 5 a was 16.3‐fold higher than the wildtype enzyme with improved stereoselectivity (98.8 % ee). More notably, the mutants Q139S and Q139S/V187S exhibited decreased or reversed stereoselectivity toward α‐tetralone 1 a, 5‐bromo‐α‐tetralone 2 a, 7‐fluoro‐α‐tetralone 5 a and 7‐chloro‐α‐tetralone 6 a, while the relatively high ee values were obtained in the presence of 6‐chloro‐α‐tetralone 3 a and 6‐bromo‐α‐tetralone 4 a as substrates. Further analysis showed the larger size of the substrates was beneficial for the substrates binding to the active cavity with a more specific binding mode, which endows the reaction with higher stereoselectivity. Moreover, the recombinant E. coli expressing the variant Q237V/I291F successfully catalyzed the reduction of a high concentration 7‐fluoro‐α‐tetralone 5 a. These results not only offered a potential tool for chiral α‐tetralols, but also provided guiding information for the enzyme engineering toward bulky‐bulky ketones. [ABSTRACT FROM AUTHOR]

The {Fe2Dy2} butterfly systems can show single molecule magnet (SMM) behaviour, the nature of which depends on details of the electronic structure, as previously demonstrated for the [Fe2Dy2(μ3‐OH)2(Me‐teaH)2(O2CPh)6] compound, where the [N,N‐bis‐(2‐hydroxyethyl)‐amino]‐2‐propanol (Me‐teaH3) ligand is usually used in its racemic form. Here, we describe the consequences for the SMM properties by using enantiopure versions of this ligand and present the first homochiral 3d/4 f SMM, which could only be obtained for the S enantiomer of the ligand for [Fe2Dy2(μ3‐OH)2(Me‐teaH)2(O2CPh)6] since the R enantiomer underwent significant racemisation. To investigate this further, we prepared the [Fe2Dy2(μ3‐OH)2(Me‐teaH)2(O2CPh)4(NO3)2] version, which could be obtained as the RS‐, R‐ and S‐compounds. Remarkably, the enantiopure versions show enhanced slow relaxation of magnetisation. The use of the enantiomerically pure ligand suppresses QTM, leading to the conclusion that use of enantiopure ligands is a "gamechanger" by breaking the cluster symmetry and altering the intimate details of the coordination cluster's molecular structure. [ABSTRACT FROM AUTHOR]