Helical Stacking Research Articles

Antimicrobial Peptide with a Bent Helix Motif Identified in Parasitic Flatworm Mesocestoides corti

The urgent need for antibiotic alternatives has driven the search for antimicrobial peptides (AMPs) from many different sources, yet parasite-derived AMPs remain underexplored. In this study, three novel potential AMP precursors (mesco-1, -2 and -3) were identified in the parasitic flatworm Mesocestoides corti, via a genome-wide mining approach, and the most promising one, mesco-2, was synthesized and comprehensively characterized. It showed potent broad-spectrum antibacterial activity at submicromolar range against E. coli and K. pneumoniae and low micromolar activity against A. baumannii, P. aeruginosa and S. aureus. Mechanistic studies indicated a membrane-related mechanism of action, and circular dichroism spectroscopy confirmed that mesco-2 is unstructured in water but forms stable helical structures on contact with anionic model membranes, indicating strong interactions and helix stacking. It is, however, unaffected by neutral membranes, suggesting selective antimicrobial activity. Structure prediction combined with molecular dynamics simulations suggested that mesco-2 adopts an unusual bent helix conformation with the N-terminal sequence, when bound to anionic membranes, driven by a central GRGIGRG motif. This study highlights mesco-2 as a promising antibacterial agent and emphasizes the importance of structural motifs in modulating AMP function.

Supramolecular Polymerization as a Tool to Reveal the Magnetic Transition Dipole Moment of Heptazines.

Heptazine derivatives have attracted significant interest due to their small S1-T1 gap, which contributes to their unique electronic and optical properties. However, the nature of the lowest excited state remains ambiguous. In the present study, we characterize the lowest optical transition of heptazine by its magnetic transition dipole moment. To measure the magnetic transition dipole moment, the flat heptazine must be chiroptically active, which is difficult to achieve for single heptazine molecules. Therefore, we used supramolecular polymerization as an approach to make homochiral stacks of heptazine derivatives. Upon formation of the supramolecular polymers, the preferred helical stacking of heptazine introduces circular polarization of absorption and fluorescence. The magnetic transition dipole moments for the S1 ← S0 and S1 → S0 are determined to be 0.35 and 0.36 Bohr magneton, respectively. These high values of magnetic transition dipole moments support the intramolecular charge transfer nature of the lowest excited state from nitrogen to carbon in heptazine and further confirm the degeneracy of S1 and T1.

Influence of ion and hydration atmospheres on RNA structure and dynamics: insights from advanced theoretical and computational methods.

RNA, a highly charged biopolymer composed of negatively charged phosphate groups, defies electrostatic repulsion to adopt well-defined, compact structures. Hence, the presence of positively charged metal ions is crucial not only for RNA's charge neutralization, but they also coherently decorate the ion atmosphere of RNA to stabilize its compact fold. This feature article elucidates various modes of close RNA-ion interactions, with a special emphasis on Mg2+ as an outer-sphere and inner-sphere ion. Through examples, we highlight how inner-sphere chelated Mg2+ stabilizes RNA pseudoknots, while outer-sphere ions can also exert long-range electrostatic interactions, inducing groove narrowing, coaxial helical stacking, and RNA ring formation. In addition to investigating the RNA's ion environment, we note that the RNA's hydration environment is relatively underexplored. Our study delves into its profound interplay with the structural dynamics of RNA, employing state-of-the-art atomistic simulation techniques. Through examples, we illustrate how specific ions and water molecules are associated with RNA functions, leveraging atomistic simulations to identify preferential ion binding and hydration sites. However, understanding their impact(s) on the RNA structure remains challenging due to the involvement of large length and long time scales associated with RNA's dynamic nature. Nevertheless, our contributions and recent advances in coarse-grained simulation techniques offer insights into large-scale structural changes dynamically linked to the RNA ion atmosphere. In this connection, we also review how different cutting-edge computational simulation methods provide a microscopic lens into the influence of ions and hydration on RNA structure and dynamics, elucidating distinct ion atmospheric components and specific hydration layers and their individual and collective impacts.

Mechanochromism and circularly polarized luminescence of chiral cyclometalated platinum(II) complexes with different configurations and aggregated forms

Using a new synthesis method, we have prepared two different coordination configurations of chiral cyclometalated N^C^N-coordinated and C^N-coordinated Pt(II) complexes by controlling the Cl− source. Single-crystal X-ray diffraction determines the tridentate and bidentate structures. All N^C^N-coordinated and C^N-coordinated Pt(II) complexes emit green-yellow light in CH2Cl2 solutions. Square-planar N^C^N-Coordinated complexes (−)-1 and (−)-2 show remarkable aggregation-induced emission behaviors in mixed CH2Cl2/n-hexane solutions with the emission quantum yield (Φem) intensified significantly. In addition, the luminescent color could change from green-yellow to red by varying the volumetric fraction of n-hexane. Complex (−)-2 grafted with long alkyl chains could form helical stacking aggregates, inducing enhanced ECD signals and measurable CPL activity. The yellow and orange solids of complex (−)-1 can be separated, and a high-contrast mechanochromic luminescence is found for the yellow form. Furthermore, the potential utility has been attempted in anti-counterfeiting applications based on the yellow solid of (−)-1. This study provides a new design strategy for the preparation of chiral cyclometalated Pt(II) complexes with specific configurations and aggregated forms that have various optical and electronic properties.

VoroNoodles: Topological Interlocking with Helical Layered 2‐Honeycombs

An approach for modeling topologically interlocked building blocks that can be assembled in a water‐tight manner (space filling) to design a variety of spatial structures is introduced. This approach takes inspiration from recent methods utilizing Voronoi tessellation of spatial domains using symmetrically arranged Voronoi sites. Attention is focused on building blocks that result from helical stacking of planar 2‐honeycombs (i.e., tessellations of the plane with a single prototile) generated through a combination of wallpaper symmetries and Voronoi tessellation. This unique combination gives rise to structures that are both space‐filling (due to Voronoi tessellation) and interlocking (due to helical trajectories). Algorithms are developed to generate two different varieties of helical building blocks, namely, corrugated and smooth. These varieties result naturally from the method of discretization and shape generation and lead to distinct interlocking behavior. In order to study these varieties, finite‐element analyses (FEA) are conducted on different tiles parametrized by 1) the polygonal unit cell determined by the wallpaper symmetry and 2) the parameters of the helical line generating the Voronoi tessellation. Analyses reveal that the new design of the geometry of the building blocks enables strong variation of the engagement force between the blocks.

Covalently Linked Hexakis(m-Phenylene Ethynylene) Macrocycles as Molecular Nanotubes.

The construction of nanotubular structures with non-deformable inner pores is of both fundamental and practical significance. Herein we report a strategy for creating molecular nanotubes with defined lengths. Macrocyclic (MC) units based on shape-persistent hexakis(m-phenylene ethynylene) (m-PE) macrocycle MC-1, which are known to stack into hydrogen-bonded tubular assemblies, are tethered by oligo(β-alanine) linkers to give tubular stacks MC-2 and MC-4 that have two and four MC units, respectively. The covalently linked MC units in MC-2 and MC-4 undergo face-to-face stacking through intramolecular non-covalent interactions that further results in the helical stacks of these compounds. Oligomer MC-4 can form potassium and proton channels across lipid bilayers, with the channels being open continuously for over 60 seconds, which is among the longest open durations for synthetic ion channels and indicates that the thermodynamic stability of the self-assembling channels can be drastically enhanced by reducing the number of molecular components involved. This study demonstrates that covalently tethering shape-persistent macrocyclic units is a feasible and reliable approach for building molecular nanotubes that otherwise are difficult to create de novo. The extraordinarily long lifetimes of the ion channels formed by MC-2 and MC-4 suggest the likelihood of constructing the next-generation synthetic ion channels with unprecedented stability.

Covalently Linked Hexakis(m‐Phenylene Ethynylene) Macrocycles as Molecular Nanotubes

AbstractThe construction of nanotubular structures with non‐deformable inner pores is of both fundamental and practical significance. Herein we report a strategy for creating molecular nanotubes with defined lengths. Macrocyclic (MC) units based on shape‐persistent hexakis(m‐phenylene ethynylene) (m‐PE) macrocycle MC‐1, which are known to stack into hydrogen‐bonded tubular assemblies, are tethered by oligo(β‐alanine) linkers to give tubular stacks MC‐2 and MC‐4 that have two and four MC units, respectively. The covalently linked MC units in MC‐2 and MC‐4 undergo face‐to‐face stacking through intramolecular non‐covalent interactions that further results in the helical stacks of these compounds. Oligomer MC‐4 can form potassium and proton channels across lipid bilayers, with the channels being open continuously for over 60 seconds, which is among the longest open durations for synthetic ion channels and indicates that the thermodynamic stability of the self‐assembling channels can be drastically enhanced by reducing the number of molecular components involved. This study demonstrates that covalently tethering shape‐persistent macrocyclic units is a feasible and reliable approach for building molecular nanotubes that otherwise are difficult to create de novo. The extraordinarily long lifetimes of the ion channels formed by MC‐2 and MC‐4 suggest the likelihood of constructing the next‐generation synthetic ion channels with unprecedented stability.

Synchronous quantitative analysis of chiral mesostructured inorganic crystals by 3D electron diffraction tomography

Chiral mesostructures exhibit distinctive twisting and helical hierarchical stacking ranging from atomic to micrometre scales with fascinating structural-chiral anisotropy properties. However, the detailed determination of their multilevel chirality remains challenging due to the limited information from spectroscopy, diffraction techniques, scanning electron microscopy and the two-dimensional projections in transmission electron microscopy. Herein, we report a general approach to determine chiral hierarchical mesostructures based on three-dimensional electron diffraction tomography (3D EDT), by which the structure can be solved synchronously according to the quantitative measurement of diffraction spot deformations and their arrangement in reciprocal space. This method was verified on two samples—chiral mesostructured nickel molybdate and chiral mesostructured tin dioxide—revealing hierarchical chiral structures that cannot be determined by conventional techniques. This approach provides more precise and comprehensive identification of the hierarchical mesostructures, which is expected to advance our understanding of structural–chiral anisotropy at the fundamental level.

Novel liquid crystals with circularly polarized luminescence induced by tartaric core

This work not only developed series of novel CPL molecules, but also confirmed that the method of designing liquid crystals with chiral core surrounded by peripheral achiral AIEgens was an effective strategy to construct the CPL materials. Three bis-cyanostilbene derivatives bridging by tartaric spacer (TC-5, TC-8 and TC-12) were prepared in yields of 81%-86%. They exhibited the orderly helical molecular stacking in mesophase and emitted the strong fluorescence at aggregated states. They possessed good CD and CPL properties based on the chiral transfer from tartrate core to peripheral cyanostilbene units. The orderly helical self-assembly in mesophase displayed the better CPL emission than the disorderly aggregation in solid films. The alkyl chains made important influence on CPL properties and TC-8 with octyl chain was the optimized structure for producing the best chiral transfer and the strongest CPL signal.

Helical Stacking Assembly of Orderly Silicon Nanowire Multilayers for Ultrastrong Dissymmetrical Amplification of Circularly Polarized Light

AbstractCircularly polarized organic light‐emitting diodes (CP‐OLEDs) are ideal candidates to explore novel applications such as 3D displays, optical storage, and quantum computing. However, the low dissymmetry (g) factor of most chiral organic materials remains as a major challenge for practical applications. In this work, a helical stacking assembly of orderly silicon nanowires (hs‐SiNWs) into a flexible multilayer 3D superstructure is demonstrated to accomplish a strong chiroptical activity. These orderly SiNWs are batch‐fabricated via a low temperature in‐plane solid–liquid–solid growth mechanism, with precisely‐controlled spatial arrangement and mean diameter and length of Dnw = 126 ± 24 nm and Lnw > 100 µm, respectively. To construct such helically‐stacked superstructure, the SiNW arrays are transferred and stacked upon transparent glass or flexible polymer substrates, with incremental rotational angle for each layer, which can strongly augment the circularly polarized electroluminescence (CPEL) from conventional CP‐OLEDs. Strikingly, the dissymmetry factor increases with more stacking layer up to g = ±0.17, which is more than 40 times of magnitude higher than that of the original CPEL, among the highest ones reported for CP‐OLEDs. These results indicate a promising helical‐stacking avenue to boost the chiroptical performance of various CP‐OLEDs for scalable and flexible chiroptical applications.

Dynamically Self-Assembled Supramolecular Probes in Liposomes

Liposomes are artificial vesicles, in which an aqueous inner compartment is separated from its environment by a phospholipid membrane. They have been extensively studied as cell membrane models and offer the possibility to confine molecules and chemical reactions to a small sub-micrometer-sized volume. This short review provides an overview of liposome-encapsulated, dynamically self-assembled, supramolecular structures, in which the assembly and disassembly of the supramolecular structures can be followed by optical spectroscopic methods. This includes self-quenched fluorescent dyes and dye/quencher pairs, helical stacks of guanosine nucleotides, dynamic covalent boronate esters, and supramolecular host–guest complexes. The resulting liposomes are typically used to study membrane transport processes, but the results summarized herein also serve as a potential blueprint for studying dynamic self-assembly in confined spaces by optical spectroscopic methods.Table of content:1 Introduction2 Probes Based on Fluorescence Quenching3 Chirogenic G-Quartet Probes4 Chromogenic Probes Using Dynamic Covalent Bonds5 Self-Assembled Host–Dye Reporter Pairs6 Conclusions and Outlook

Exciton interactions in helical crystals of a hydrogen-bonded eumelanin monomer.

Eumelanin, a naturally occurring group of heterogeneous polymers/aggregates providing photoprotection to living organisms, consist of 5,6-dihydroxyindole (DHI) and 5,6-dihydroxyindole-2-carboxylic acid (DHICA) building blocks. Despite their prevalence in the animal world, the structure and therefore the mechanism behind the photoprotective broadband absorption and non-radiative decay of eumelanin remain largely unknown. As a small step towards solving the incessant mystery, DHI is crystallized in a non-protic solvent environment to obtain DHI crystals having a helical packing motif. The present approach reflects the solitary directional effect of hydrogen bonds between the DHI chromophores for generating the crystalline assembly and filters out any involvement of the surrounding solvent environment. The DHI single crystals having an atypical chiral packing motif (P212121 Sohncke space group) incorporate enantiomeric zig-zag helical stacks arranged in a herringbone fashion with respect to each other. Each of the zig-zag helical stacks originates from a bifurcated hydrogen bonding interaction between the hydroxyl substituents in adjacent DHI chromophores which act as the backbone structure for the helical assembly. Fragment-based excited state analysis performed on the DHI crystalline assembly demonstrates exciton delocalization along the DHI units that connect each enantiomeric helical stack while, within each stack, the excitons remain localized. Fascinatingly, over the time evolution for generation of single-crystals of the DHI-monomer, mesoscopic double-helical crystals are formed, possibly attributed to the presence of covalently connected DHI trimers in chloroform solution. The oligomeric DHI (in line with the chemical disorder model) along with the characteristic crystalline packing observed for DHI provides insights into the broadband absorption feature exhibited by the chromophore.

Theory of Apparent Circular Dichroism Reveals the Origin of Inverted and Noninverted Chiroptical Response under Sample Flipping.

Circular dichroism (CD) finds widespread application as an optical probe for the structure of molecules and supramolecular assemblies. Its underlying chiral light-matter interactions effectively couple between photonic spin states and select quantum-mechanical degrees of freedom in a sample, implying an intricate connection with photon-to-matter quantum transduction. However, effective transduction implementations likely require interactions that are antisymmetric with respect to the direction of light propagation through the sample, yielding an inversion of the chiroptical response upon sample flipping, which is uncommon for CD. Recent experiments on organic thin films have demonstrated such chiroptical behavior, which was attributed to "apparent CD" resulting from an interference between the sample's linear birefringence and linear dichroism. However, a theory connecting the underlying optical selection rules to the microscopic electronic structure of the constituent molecules remains to be formulated. Here, we present such a theory based on a combination of Mueller calculus and a Lorentz oscillator model. The theory reaches good agreement with experimental CD spectra and allows for establishing the (supra)molecular design rules for maximizing or minimizing this chiroptical effect. It furthermore highlights that, in addition to antisymmetrically, it can manifest symmetrically such that no chiroptical response inversion occurs, which is a consequence of a helical stacking of molecules in the light propagation direction.

Biphenyl-Induced Superhelix in l -Phenylalanine-Based Supramolecular Self-Assembly with Dynamic Morphology Transitions

Biphenyl-Induced Superhelix in <scp>l</scp> -Phenylalanine-Based Supramolecular Self-Assembly with Dynamic Morphology Transitions

Suppression of antiferromagnetic order and strong ferromagnetic spin fluctuations in Ca(Co1−xNix)2−yAs2 single crystals

${\mathrm{CaCo}}_{2\ensuremath{-}y}{\mathrm{As}}_{2}$ is a unique itinerant system having strong magnetic frustration. Here, we report the effect of electron doping on the physical properties resulting from Ni substitutions for Co. The single crystals of $\mathrm{Ca}{({\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Ni}}_{x})}_{2\ensuremath{-}y}{\mathrm{As}}_{2}$ were characterized by single-crystal x-ray diffraction, energy-dispersive x-ray spectroscopy, magnetization $M$ versus temperature $T$, magnetic field $H$, time $t$, and heat capacity ${C}_{\mathrm{p}}(H,T)$ measurements. The A-type antiferromagnetic (AFM) transition temperature ${T}_{\mathrm{N}}=52$ K for $x=0$ decreases to 22 K with only 3% Ni substitution and is completely suppressed for $x&gt;0.16$. For $0.11\ensuremath{\le}x\ensuremath{\le}0.52$ strong ferromagnetic (FM) fluctuations develop as revealed by magnetic susceptibility $\ensuremath{\chi}(T)=M(T)/H$ measurements. For $x=0.11$ and 0.16 competing AFM and FM interactions result in a reentrant spin-glass behavior below ${T}_{\mathrm{N}}$, as evidenced by the observations of thermomagnetic hysteresis and magnetic relaxation. Enhanced FM fluctuations are also found for the $x=0.21$ and 0.31 crystals, where ${\ensuremath{\chi}}_{c}$ increases significantly at low $T$. A large $\ensuremath{\chi}$ anisotropy in these compositions where ${\ensuremath{\chi}}_{c}$ is up to a factor of two larger than ${\ensuremath{\chi}}_{ab}$ suggests that the FM spin fluctuations are quasi-1D in nature. Weak ferromagnetic contributions to the magnetization are found at $T=2$ K for $x=0.11$--0.31. Heat-capacity ${C}_{\mathrm{p}}(T)$ measurements reveal the presence of FM quantum spin fluctuations for $0.11\ensuremath{\le}x\ensuremath{\le}0.52$, where a logarithmic $T$ dependence of ${C}_{\mathrm{p}}(T)/T$ is observed at low $T$. The suppression of AFM order by the development of strong FM fluctuations in $\mathrm{Ca}{({\mathrm{Co}}_{1\ensuremath{-}x}{\mathrm{Ni}}_{x})}_{2\ensuremath{-}y}{\mathrm{As}}_{2}$ crystals suggests the presence of a FM quantum-critical point at $x\ensuremath{\approx}0.20$. Our density-functional theory (DFT) calculations confirm that FM fluctuations are enhanced by Ni substitutions for Co in ${\mathrm{CaCo}}_{2\ensuremath{-}y}{\mathrm{As}}_{2}$. The Sommerfeld electronic heat-capacity coefficient is enhanced for $x=0$, 0.21, and 0.42 by about a factor of two compared to DFT calculations of the density of states (DOS) at the Fermi energy, suggesting an enhancement of the DOS from electron-phonon and/or electron-electron interactions. The crystals with $x&gt;0.52$ do not exhibit FM spin fluctuations or magnetic order at $T\ensuremath{\ge}1.8$ K, which was found from the DFT calculations to arise from a Stoner transition. Superconductivity is not observed above 1.8 K for any of the compositions. Neutron-diffraction studies of crystals with $x=0.11$ and 0.16 in the crossover regime $(0.1\ensuremath{\lesssim}x\ensuremath{\lesssim}0.2)$ show no evidence of A-type ordering as observed in the parent compound with $x=0$. Furthermore, no other common magnetic structures, such as ferromagnetic (FM), helical stacking of in-plane FM layers, or in-plane AFM structure, are found with an ordered moment greater than the uncertainty of $0.05\phantom{\rule{0.28em}{0ex}}{\ensuremath{\mu}}_{\mathrm{B}}$ per transition-metal atom.

Toward large-scale CVD graphene growth by enhancing reaction kinetics via an efficient interdiffusion mediator and mechanism study utilizing CFD simulations

BackgroundThe yield rate for the synthesis of large-area and high-quality graphene, based on the chemical vapor deposition (CVD) method, is limited by the reactor size of a tubular furnace. Additionally, the reported methods to achieve a high-throughput process are still challenging. Currently, the rolled-up or vertically stacked configuration setup is applied to increase the loading growth. However, the reported methods limit the kinetic reaction of CVD growth and lead to the degradation of the uniformity and crystallinity of as-grown graphene. MethodsHere, we propose a novel method to produce a high-yield and uniform monolayer graphene film by helical stacking of Cu with highly porous carbon cloth as an efficient interdiffusion mediator. Additionally, computational fluid dynamics (CFD) is applied to simulate the dynamic distribution within the mediator. Significant FindingsThis method allows the rapid synthesis of graphene films of up to 900 cm2 for each batch of growth in a 1-inch furnace. Graphene with optimized conditions exhibits a high crystallinity (ID/IG: 0.16) and electrical conductivity (760 Ω/sq). The comprehensive study on recipe optimization together with the multiphysical simulation suggests that the proposed carbon cloth is an ideal spacing mediator for CVD graphene with a high Cu-loading density. This enhancement is attributed to the homogeneous interdiffusion of reactive gas/species in both the transverse and radial directions, resulting in homogeneous nucleation and equivalent kinetic growth. The capacity could reach 15.56 m2/hour in an 8-inch system. The CFD simulation indicates that the porous mediator can improve gas distribution and balance the pressure between the Cu foils to enhance high-yield graphene synthesis. This method provides an efficient strategy for the synthesis of high-throughput and large-area CVD graphene films, which is beneficial for cost-effective and versatile graphene-based applications.

Resistance-Chiral Anisotropy of Chiral Mesostructured Half-metallic Fe3 O4 Films.

Half-metallic materials are theoretically predicted to be metallic and insulating, which have not been confirmed experimentally, and the predictions are still in doubt. We report the resistance-chiral anisotropy (R-ChA), i.e., chirality-dependent electrical conductivity, in chiral mesostructured Fe3 O4 films (CMFFs) grown on the substrates via a hydrothermal method using amino acids as symmetry-breaking agents. Two levels of chirality exist in the CMFFs: primary distortion of the crystal lattice forms twisted nanoflakes, and secondary helical stacking of nanoflakes forms fan-shaped nanoplates. At temperatures below 30 K, the CMFFs exhibited metallic conductivity and insulation for one handedness and the other, respectively. The chirality-dependent effective magnetic fields were speculated to stabilize the opposite spin in the antipodal chiral frame, which led to the free transport of electrons in one handedness of the chiral structure and immobility for the other handedness.

Resistance‐Chiral Anisotropy of Chiral Mesostructured Half‐metallic Fe3O4 Films

AbstractHalf‐metallic materials are theoretically predicted to be metallic and insulating, which have not been confirmed experimentally, and the predictions are still in doubt. We report the resistance‐chiral anisotropy (R‐ChA), i.e., chirality‐dependent electrical conductivity, in chiral mesostructured Fe3O4 films (CMFFs) grown on the substrates via a hydrothermal method using amino acids as symmetry‐breaking agents. Two levels of chirality exist in the CMFFs: primary distortion of the crystal lattice forms twisted nanoflakes, and secondary helical stacking of nanoflakes forms fan‐shaped nanoplates. At temperatures below 30 K, the CMFFs exhibited metallic conductivity and insulation for one handedness and the other, respectively. The chirality‐dependent effective magnetic fields were speculated to stabilize the opposite spin in the antipodal chiral frame, which led to the free transport of electrons in one handedness of the chiral structure and immobility for the other handedness.

Chiral Mesostructured BiOBr Films with Circularly Polarized Colour Response

AbstractAchieving strong and broadband circularly polarized colour responses in chiral inorganic materials is challenging. Here, we fabricated chiral mesostructured bismuth oxybromide (BiOBr) films (CMBFs) via hydrothermal growth using chiral sugar alcohols as symmetry‐breaking agents. The layered slabs of BiOBr crystals with weak van‐der‐Waals interactions are prone to mismatching due to the chiral driving force, resulting in hierarchically chiral arrangements of fine size. Three levels of chirality exist in the CMBFs: primary, helical distortion crystal lattices of a nanoflake, secondary, helical stacking of nanoflakes to form nanoplates, and tertiary, chiral vortexes arranged by nanoplates. The CMBFs displayed optical activities (OAs) over a wide wavelength range of 350–2500 nm with an anisotropic factor of up to 0.99, which led to a significant chirality‐dependent colour response to circularly polarized light. The high selectivity can be considered as the result of enhanced resonance due to structural‐handedness matching and the synergistic effect of multiple OAs.

X-ray Fiber Diffraction and Computational Analyses of Stacked Hexads in Supramolecular Polymers: Insight into Self-Assembly in Water by Prospective Prebiotic Nucleobases

Aqueous solutions of equimolar mixtures of 2,4,6-triaminopyrimidine (TAP) and carboxylic acid substituted cyanuric acid (CyCo6 or R-4MeCyCo6) monomers self-assemble into gel-forming supramolecular polymers. Macroscopic fibers drawn from these mixtures were analyzed by X-ray diffraction to determine their molecular structures. Computational methods were used to explore the intrinsic intermolecular interactions that contribute to the structure and stability of these assemblies. Both polymers are formed by the stacking of hexameric rosettes, (TAP/CyCo6)3 or (TAP/R-4MeCyCo6)3, respectively, into long, stiff, twisted stacks of essentially planar rosettes. Chiral, left-handed supramolecular polymers with a helical twist angle of -26.7° per hexad are formed when the pure enantiomer R-4MeCyCo6 is used. These hexad stacks pack into bundles with a hexagonal crystalline lattice organization perpendicular to the axis of the macroscopic fiber. Polymers formed from TAP and CyCo6, both of which are achiral, assemble into macroscopic domains that are packed as a centered rectangular lattice. Within these domains, the individual polymers exist as either right-handed or left-handed helical stacks, with twist angles of +15° or -15° per hexad, respectively. The remarkable ability of TAP and cyanuric acid derivatives to self-assemble in water, and the structural features of their supramolecular polymers reported here, provide additional support for the proposal that these heterocycles could have served as recognition units for an early form of nucleic acids, before the emergence of RNA.