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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]

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]

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]

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]

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]

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]