Reversible Local Protonation-Deprotonation: Tuning Stimuli-Responsive Circularly Polarized Luminescence in Chiral Hybrid Zinc Halides for Anti-Counterfeiting and Encryption

Precise control over the organic composition is crucial for tailoring the distinctive structures and properties of hybrid metal halides. However, this approach is seldom utilized to develop materials that exhibit stimuli-responsive circularly polarized luminescence (CPL). Herein, we present the synthesis and characterization of enantiomeric hybrid zinc bromides: biprotonated ((R/S)-C12H16N2)ZnBr4 ((R/S-LH2)ZnBr4) and monoprotonated ((R/S)-C12H15N2)2ZnBr4 ((R/S-LH1)2ZnBr4), derived from the chiral organic amine (R/S)-2,3,4,9-Tetrahydro-1H-carbazol-3-amine ((R/S)-C12H14N2). These compounds showcase luminescent properties; the zero-dimensional biprotonated form emits green light at 505 nm, while the monoprotonated form, with a pseudo-layered structure, displays red luminescence at 599 and 649 nm. Remarkably, the reversible local protonation-deprotonation behavior of the organic cations allows for exposure to polar solvents and heating to induce reversible structural and luminescent transformations between the two forms. Theoretical calculations reveal that the lower energy barrier associated with the deprotonation process within the pyrrole ring is responsible for the local protonation-deprotonation behavior observed. These enantiomorphic hybrid zinc bromides also exhibit switchable circular dichroism (CD) and CPL properties. Furthermore, their chloride counterparts were successfully obtained by adjusting the halogen ions. Importantly, the unique stimuli-responsive CPL characteristics position these hybrid zinc halides as promising candidates for applications in information storage, anti-counterfeiting, and information encryption.

Pathway-directed recyclable chirality inversion of coordinated supramolecular polymers

It remains challenging to elucidate the fundamental mechanisms behind the dynamic chirality inversion of supramolecular assemblies with pathway complexity. Herein, metal coordination driven assembly systems based on pyridyl-conjugated cholesterol (PVPCC) and metal ions (Ag+ or Al3+) are established to demonstrate pathway-directed, recyclable chirality inversion and assembly polymorphism. In the Ag(I)/PVPCC system, a competitive pathway leads Ag-Complex to form either kinetically controlled supramolecular polymer (Ag-SP I) or thermodynamically favored Ag-SP II, accompanied by reversible chiroptical inversion. Conversely, the Al(III)/PVPCC system displays a solvent-assisted consecutive pathway: the Al-Complex initially forms ethanol-containing Al-SP II, and subsequently converts into ethanol-free Al-SP I with opposite chiroptical performance upon thermal treatment. Moreover, stable chirality inversion in the solid state enables potential dynamic circularly polarized luminescence encryption when Ag(I)/PVPCC is co-assembled with thioflavin T. These findings provide the guidance for the dynamic modulation of chirality functionality in supramolecular materials for applications in information processing, data encryption, and chiral spintronics.

Chiral nanoenzymes: synthesis and applications

Chiral nanoenzymes are a new type of material that possesses both chiral nanostructures and enzymatic catalytic activity. These materials exhibit selectivity in their catalytic activity towards organisms due to the introduction of chiral features in nanomaterials and have inherent chiral discrimination in organisms. As synthetic enzymes, chiral nanoenzymes offer significant advantages over natural enzymes. Due to their unique chiral structure and distinctive physicochemical properties, chiral nanoenzymes play an important role in various fields, including biology, medicine, and environmental protection. Their strong stereospecificity and biocompatibility make them useful in disease therapy, biosensing, and chiral catalysis, setting them apart from conventional and natural enzymes. In recent years, the design of synthetic methods and biological applications of chiral nanoenzymes has received significant attention and extensive research among scientists. This paper provides a systematic review of the research progress in the discovery, development, and application of chiral nanoenzymes in the last decade. Additionally, it presents various applications of chiral nanoenzymes, such as disease therapy, biosensing, and chiral catalysis. Finally, the challenges and future prospects of chiral nanoenzymes are discussed.

Supramolecular gels: a versatile crystallization toolbox

Supramolecular gels are unique materials formed through the self-assembly of molecular building blocks, typically low molecular weight gelators (LMWGs), driven by non-covalent interactions. The process of crystallization within supramolecular gels has broadened the scope of the traditional gel-phase crystallization technique offering the possibility of obtaining crystals of higher quality and size. The broad structural diversity of LMWGs allows crystallization in multiple organic and aqueous solvents, favouring screening and optimization processes and the possibility to search for novel polymorphic forms. These supramolecular gels have been used for the crystallization of inorganic, small organic compounds of pharmaceutical interest, and proteins. Results have shown that these gels are not only able to produce crystals of high quality but also to influence polymorphism and physicochemical properties of the crystals, giving rise to crystals with potential new bio- and technological applications. Thus, understanding the principles of crystallization in supramolecular gels is essential for tailoring their properties and applications, ranging from drug delivery systems to composite crystals with tunable stability properties. In this review, we summarize the use of LMWG-based supramolecular gels as media to grow single crystals of a broad range of compounds.

Chiral Co-assembly Based on a Stimuli-Responsive Polymer towards Amplified Full-Color Circularly Polarized Luminescence

Stimuli-responsive circularly polarized luminescence (CPL) materials have been attaching wide attention in the field of optical information storage and encryption, while still facing the challenge of the realization of high luminescence dissymmetry factors (glum). This work presents a pair of stimuli-responsive chiral co-assemblies P7R3 and P7S3 by combining polymer PFIQ containing iso-quinoline units with chiral inducers. The obtained chiral co-assemblies can reversibly undergo significant modification in CPL behavior under trifluoroacetic acid (TFA) fumigation and annealing treatment, with the |glum| values exhibiting a reversible shift between 0.2 and 0.3. Moreover, the chiral co-assemblies before TFA fumigating can effectively induce achiral emitters to generate intense full-color CPL signals through CPL energy transfer (CPL-ET), with the corresponding |glum| values larger than 0.2. Moreover, information encryption and decryption as well as a multi-level logic gates application are achieved by leveraging the reversible stimuli-responsive CPL activity of the chiral co-assembly. This work provides a new perspective for the construction of stimuli-responsive chiral luminescent materials with large |glum| values and the activation of CPL behavior in achiral emitters.

Ratiometric Chemosensors That Are Capable of Quantifying Hydrostatic Pressure Stimulus: A Case of Porphyrin Tweezers

Investigating chemosensors that are capable of quantifying pressure in solution, particularly hydrostatic pressure, which is one of the mechanical forces, is an attractive challenge in chemistry from the viewpoint of "mechano"-science. Herein, we report the investigation of chiral porphyrin tweezers, Por-Cy and Por-DPhEt, comprising different flexible linkers; Por-Cy and Por-DPhEt displayed distinct ratiometric signaling by using the higher excited S2 state with a standard excited S1 level. A novel operative mechanism using the S1/S2 fluorescence ratio was revealed using hydrostatic pressure-ultraviolet/visible (UV/vis), fluorescence/excitation, circular dichroism spectroscopy, and lifetime measurements, which can be further controlled by the open-closed conformational change inherent in the tweezer skeleton. Furthermore, the fluorescent chiral tweezers exhibited a promising |g lum| of 2.9 × 10-3, indicating that they are potential candidates for sensory applications in chiral environments. This study provides opportunities for the development of smart pressure-responsive chemosensors.

Multiple Chirality Switching of a Dye-Grafted Helical Polymer Film Driven by Acid & Base

A stimuli-responsive multiple chirality switching material, which can regulate opposed chiral absorption characteristics, has great application value in the fields of optical modulation, information storage and encryption, etc. However, due to the rareness of effective functional systems and the complexity of material structures, developing this type of material remains an insurmountable challenge. Herein, a smart polymer film with multiple chirality inversion properties was fabricated efficiently based on a newly-designed acid & base-sensitive dye-grafted helical polymer. Benefited from the cooperative effects of various weak interactions (hydrogen bonds, electrostatic interaction, etc.) under the aggregated state, this polymer film exhibited a promising acid & base-driven multiple chirality inversion property containing record switchable chiral states (up to five while the solution showed three-state switching) and good reversibility. The creative exploration of such a multiple chirality switching material can not only promote the application progress of current chiroptical regulation technology, but also provide a significant guidance for the design and synthesis of future smart chiroptical switching materials and devices.

Recent Advances of Organic Cocrystals in Emerging Cutting-Edge Properties and Applications

Organic cocrystals, representing one type of new functional materials, have gathered significant interest in various engineering areas. Owing to their diverse stacking modes, rich intermolecular interactions and abundant functional components, the physicochemical properties of organic cocrystals can be tailored to meet different requirements and exhibit novel characteristics. The past few years have witnessed the rapid development of organic cocrystals in both fundamental characteristics and various applications. Beyond the typical properties like ambipolarity, emission tuning ability, ferroelectricity, etc. that are previously well demonstrated, many novel, impressive and cutting-edge properties and applications of cocrystals are also emerged and advanced recently. Especially during the nearest five years, photothermal conversion, room-temperature phosphorescence, thermally activated delay fluorescence, circularly polarized luminescence, organic solid-state lasers, near-infrared sensing, photocatalysis, batteries, and stimuli responses have been reported. In this review, these new properties are carefully summarized. Besides, some neoteric architecture and methodologies, such as host-guest structures and machine learning-based screening, are introduced. Finally, the potential future developments and expectations for organic cocrystals are discussed for further investigations on multiple functions and applications.

Multi-Stimuli-Responsive Network of Multicatalytic Reactions using a Single Palladium/Platinum Catalyst

Given her unrivalled proficiency in the synthesis of all molecules of life, nature has been an endless source of inspiration for developing new strategies in organic chemistry and catalysis. However, one feature that remains thus far beyond chemists' grasp is her unique ability to adapt the productivity of metabolic processes in response to triggers that indicate the temporary need for specific metabolites. To demonstrate the remarkable potential of such stimuli-responsive systems, we present a metabolism-inspired network of multicatalytic processes capable of selectively synthesising a range of products from simple starting materials. Specifically, the network is built of four classes of distinct catalytic reactions-cross-couplings, substitutions, additions, and reductions, involving three organic starting materials-terminal alkyne, aryl iodide, and hydrosilane. All starting materials are either introduced sequentially or added to the system at the same time, with no continuous influx of reagents or efflux of products. All processes in the system are catalysed by a multifunctional heteronuclear PdII/PtII complex, whose performance can be controlled by specific additives and external stimuli. The reaction network exhibits a substantial degree of orthogonality between different pathways, enabling the controllable synthesis of ten distinct products with high efficiency and selectivity through simultaneous triggering and suppression mechanisms.

A photoactivated chiral molecular clamp rotated by selective anion binding

Developing chiral molecular platforms that respond to external fields provides opportunities for designing smart chiroptical materials. Herein, we introduce a molecular clamp whose chiral properties can be turned on by photoactivation. Selective anion binding achieves rational tuning of the conformations and chiroptical properties of the clamp, including circular dichroism and circularly polarized luminescence. Cyanostilbene segments were conjugated to chiral amines with a rotatable axis. Negligible chiroptical signals were significantly enhanced through a light illumination-induced isomerization. Binding with halide ions (F-, Cl- and Br-) enables chiroptical inversion and subsequent amplification of the resulting opposite handedness state by photo treatment. In contrast, the larger I- and NO3 - ions failed to achieve chiroptical inversion. Also the handedness inversion was hampered in conformationally locked amines. Density-functional theory-based computational studies and experimental results reveal a structural transformation that proceeds from a butterfly-like open geometry to a closed V-shaped state initiated by four hydrogen bonds and the rotatable axis. This work illustrates design protocols for use in smart chiroptical molecular platforms mediated by photo treatment and anion binding.

A Double Twisted Nanographene with a Contorted Pyrene Core

The mature synthetic methodologies enable us to rationally design and produce chiral nanographenes (NGs), most of which consist of multiple helical motifs. However, inherent chirality originating from twisted geometry has just emerged to be employed in chiral NGs. Herein, we report a red-emissive chiral NG constituted of orthogonally arranged two-fold twisted π-skeletons at a contorted pyrene core which contributes to optical transitions of S0→S1 and vice versa. The thus-obtained NG exhibited a robustness on its redox properties through 2e- uptake/release. The chemical oxidation generated stable radical cation whose absorption covers near-infrared I and II regions. Overall, the contorted pyrene core governs electronic nature of the chiral NG. The twist operation on NGs would be, therefore, a design strategy to alter conventional chirality induction on NGs.

Amplification and Attenuation of Asymmetry via Kinetically Controlled Seed-Induced Supramolecular Polymerization

The amplification of asymmetry in supramolecular polymers has recently garnered significant attention. While asymmetry amplification has predominantly been explored under thermodynamic conditions, the kinetic aspect of this process unveils intriguing observations, yet is scarcely reported in the literature. Herein, drawing inspiration from macromolecular systems, we propose a novel strategy for enhancing asymmetry in supramolecular polymers through a seed-induced supramolecular polymerization approach under kinetic conditions, employing a naphthalene diimide-derived monomer (ANSG) for template-induced supramolecular polymerization, utilizing adenosine triphosphate (ATP) and pyrophosphate (PPi) as templates. A chiral seed comprising [ANSG-ATP]S effectively amplifies the overall supramolecular asymmetry when exposed to a mixture of achiral templates (PPi) and monomers (ANSG), owing to its efficient seeding characteristics under kinetic conditions. As a result of efficient co-operativity, conversely, employing an achiral seed [ANSG-PPi]S in a mixture of chiral templates (ATP) and monomers (ANSG) results in the attenuation of asymmetry, highlighting the effective modulation achievable through the seeding approach, an unprecedented observation in the field. Exploiting the efficient aggregation-induced emission enhancement (AIEE) of the resultant supramolecular polymers further extends the amplification and attenuation of circularly polarized luminescence (CPL) as a potential function.

Modulating Helix-Preference of an Axially-Twisted Molecular Scaffold Through Diastereomeric Salt Formation with Tartaric Acid Stereoisomers

Herein, we designed a chiral, axially-twisted molecular scaffold (ATMS) using pyridine-2,6-dicarboxamide (PDC) unit as pivot, chiral trans-cyclohexanediamine (CHDA) residues as linkers, and pyrene residues as fluorescent reporters. R,R-ATMS exclusively adopted M-helicity and produced differential response in UV-vis, fluorescence, and NMR upon addition of tartaric acid (TA) stereoisomers allowing naked-eye detection and enantiomeric content determination. Circular dichroism (CD) profile of R,R-ATMS underwent unique changes during titration with TA stereoisomers - while loss of CD signal at 345 nm was observed with equimolar D-TA and meso-TA, inversion was seen with equimolar L-TA. Temperature increase weakened these interactions to partially recover the original CD signature of R,R-ATMS. 2D NMR studies also indicated the significant structural changes in R,R-ATMS in the solution state upon addition of L-TA. Single crystal X-ray diffraction (SCXRD) studies on the crystals of the R,R-ATMS⊃D-TA salt revealed the interacting partners stacked in arrays and ATMS molecules stabilized by π-π stacking between its PDC and pyrene residues. Contrastingly, tightly-packed supramolecular cages comprised of four molecules each of R,R-ATMS and L-TA were seen in R,R-ATMS⊃L-TA salt, and the ATMS molecules contorted to achieve CH-π interactions between its pyrene residues. These results may have implications in modulating the helicity of topologically-similar larger biomolecules.

Strong coupling of an epsilon-near-zero mode to a chiral plasmon

The reconfigurable chiroptical effect is highly desirable for spin photonics, chiral spectroscopy, and photocatalysis due to its merits for dynamic and broadband applications. The coupling of an epsilon-near-zero (ENZ) mode to a chiral plasmon is expected to enable active and effective manipulation of the chiroptical effect but remains unexplored. Here we, for the first time to our knowledge, propose and demonstrate the strong coupling of an ENZ mode to a chiral plasmon by using a hybrid system composed of two identical vertically placed gold nanorods and an in-between ENZ film. An analytical three-oscillator model combined with numerical simulations is established to study the coupling mechanism, which predicts a Rabi splitting up to 240 meV with an ENZ film thickness of 60 nm in circular dichroism.

Multidimensional Dynamic Control of Supramolecular Phthalocyanine Gear: A Self-Assembly System Responding to Solvent, Temperature, and Hydrostatic Pressure

Smart supramolecular materials that respond toward various external stimuli hold great promise for various applications in molecular memories, logic gates, and drug delivery systems. In this study, the active control over the self-assembly of phathalocyanine gear was achieved by combining temperature and hydrostatic pressure stimuli with a dynamic solvent. Eventually, we found that the supramolecular gear can behave as a logic gate; "engaged" (+1) or "not" (0) state is switchable by solvent, temperature, and hydrostatic pressure. This paper describes not only new aspects for the rational design of smart stimuli-responsive supramolecular materials but also the significance of multidimensional dynamic control.

Lighting Up Bispyrene-Functionalized Chiral Molecular Muscles with Switchable Circularly Polarized Excimer Emissions

Aiming at the further extension of the application scope of traditional molecular muscles, a novel bispyrene-functionalized chiral molecular [c2]daisy chain was designed and synthesized. Taking advantage of the unique dimeric interlocked structure of molecular [c2]daisy chain, the resultant chiral molecular muscle emits strong circularly polarized luminescence (CPL) attributed to the pyrene excimer with a high dissymmetry factor (glum) value of 0.010. More importantly, along with the solvent- or anion- induced motions of the chiral molecular muscle, the precise regulation of the pyrene stacking within its skeleton results in the switching towards either "inversed" state with sign inversion and larger glum values or "down" state with maintained handedness and smaller glum values, making it a novel multistate CPL switch. As the first example of chiral molecular muscle-based CPL switch, this proof-of-concept study not only successfully widens the application scopes of molecular muscles, but also provides a promising platform for the construction of novel smart chiral luminescent materials for practical applications.

Switchable Dual Circularly Polarized Luminescence in Through-Space Conjugated Chiral Foldamers

Organic materials with switchable dual circularly polarized luminescence (CPL) are highly desired because they can not only directly radiate tunable circularly polarized light themselves but also induce CPL for guests by providing a chiral environment in self-assembled structures or serving as the hosts for energy transfer systems. However, most organic molecules only exhibit single CPL and it remains challenging to develop organic molecules with dual CPL. Herein, novel through-space conjugated chiral foldamers are constructed by attaching two biphenyl arms to the 9,10-positions of phenanthrene, and switchable dual CPL with opposite signs at different emission wavelengths are successfully realized in the foldamers containing high-polarizability substitutes (cyano, methylthiol and methylsulfonyl). The combined experimental and computational results demonstrate that the intramolecular through-space conjugation has significant contributions to stabilizing the folded conformations. Upon photoexcitation in high-polar solvents, strong interactions between the biphenyl arms substituted with cyano, methylthio or methylsulfonyl and the polar environment induce conformation transformation for the foldamers, resulting in two transformable secondary structures of opposite chirality, accounting for the dual CPL with opposite signs. These findings highlight the important influence of the secondary structures on the chiroptical property of the foldamers and pave a new avenue towards efficient and tunable dual CPL materials.

Handedness-Inverted and Stimuli-Responsive Circularly Polarized Luminescent Nano/Micromaterials Through Pathway-Dependent Chiral Supramolecular Polymorphism

The precise manipulation of supramolecular polymorphs has been widely applied to control the morphologies and functions of self-assemblies, but is rarely utilized for the fabrication of circularly polarized luminescence (CPL) materials with tailored properties. Here, this work reports that an amphiphilic naphthalene-histidine compound (NIHis) readily self-assembled into distinct chiral nanostructures through pathway-dependent supramolecular polymorphism, which shows opposite and multistimuli responsive CPL signals. Specifically, NIHis display assembly-induced CPL from the polymorphic keto tautomer, which become predominant during enol-keto tautomerization shifting controlled by a bulk solvent effect. Interestingly, chiral polymorphs of nanofiber and microbelt with inverted CPL signals can be prepared from the same NIHis monomer in exactly the same solvent compositions and concentrations by only changing the temperature. The tunable CPL performance of the solid microbelts is realized under multi external physical or chemical stimuli including grinding, acid fuming, and heating. In particular, an emission color and CPL on-off switch based on the microbelt polymorph by reversible heating-cooling protocol is developed. This work brings a new approach for developing smart CPL materials via supramolecular polymorphism engineering.

An enzymolysis-induced energy transfer co-assembled system for spontaneously recoverable supramolecular dynamic memory

The continuing growth of the digital world requires new ways of constructing memory devices to process and store dynamic data, because the current ones suffer from inefficiency, limited reads, and difficulty to manufacture. Here we propose a supramolecular dynamic memory (SDM) strategy based on an enzymolysis-induced energy transfer co-assembly derived from a naphthalene-based cationic monomer and organic dye sulforhodamine 101, enabling the construction of spontaneously recoverable dynamic memory devices. Benefitting from the large exciton migration rate (4.48 × 1015 L mol-1 s-1) between the monomer and sulforhodamine 101, the energy transfer process between the two is effectively achieved. Since alkaline phosphatase can selectively hydrolyze adenosine triphosphate, leading to the disruption of the co-assemblies, an enzyme-mediated time-dependent fluorochromic system is realized. On this basis, a SDM system featuring spontaneous recovery and enabling the memory of dynamic information in optical and electrical modes is successfully constructed. The current study represents a promising step in the nascent development of supramolecular materials for computational systems.

Enantiomerically Resolvable Inherent Chirality Induced by Strong Para-Steric Hindrance in Cycloparaphenylene-Based Carbon Nanohoops

The chemical modification of the achiral carbon nanohoops to break the symmetry will result in inherently chiral structures with interesting optical properties. Herein, we report two novel π-extended chiral macrocycles, cyclo[10]paraphenylene-pyrene ([10]CPP-2Pyrene) and cyclo[10]paraphenylene-hexa-peri-hexabenzocoronene ([10]CPP-2HBC). The large substituents on the nanohoop peripheries effectively prevented free rotation and the racemization process. The conformation of each enantiomer is stable enough to be resolved by recycling HPLC.

Photon Upconversion Cooperates with Downshifting in Chiral Systems: Modulation, Amplification, and Applications of Circularly Polarized Luminescence

Circularly polarized luminescence (CPL)-active materials are increasingly recognized for their potential applications such as 3D imaging, data storage, and optoelectronic devices. Typically, CPL materials have required high-energy (HE) photons for excitation to emit low-energy (LE) circularly polarized light, a process known as downshifting CPL (DSCPL). However, the emergence of upconverted CPL (UCCPL), where the absorption of multi LE photons results in the emission of a single HE photon with circular polarization, has recently attracted considerable attention. This minireview highlights the intricate relationship between upconversion and CPL phenomena. During upconversion, the dissymmetry factor (glum) value can be improved in certain systems. Additionally, the integration of both LE and HE photons in upconversion-downshifting-synergistic systems offers avenues for dual-excitation or dual-emission CPL functionalities. More in detail, the emerging UCCPL based on various photon upconversion mechanisms and their synergy with DSCPL are introduced. Additionally, several examples that demonstrate the applications of UCCPL are presented to highlight the future opportunities.

Cholesterol-substituted spiropyran: Photochromism, thermochromism, mechanochromism and its application in time-resolved information encryption

Organic multi-stimulus-responsive materials are widely used in anti-counterfeiting and information encryption due to their unique response characteristics and designability. However, progress in obtaining multi-stimulus-responsive smart materials has been very slow. Herein, a spiropyran derivative is constructed, which shows photochromic, thermochromic and mechanical photochromic properties, and has reversible absorption/luminescence adjustment ability. By introducing non-covalent interactions such as van der Waals force and hydrogen bond, this new molecule is more sensitive to external stimuli and exhibits better photochromic, mechanochromic and thermochromic properties with rapid speed and high contrast. Furthermore, these three stimulus responses can be completely restored to the initial state under white light irradiation. The reversible multiple response characteristics of this molecule make it possible to provide dynamic anti-counterfeiting and advanced information encryption capabilities. To demonstrate its application in advanced information encryption, powders treated with different stimuli are combined with fluorescent dyes to encrypt complex digital information. This work puts forward a new time-resolved encryption strategy, which provides important guidance for the development of time-resolved information security materials.

When quantum dots meet blue phase liquid crystal elastomers: visualized full-color and mechanically-switchable circularly polarized luminescence

Polymer-based circularly polarized luminescence (CPL) materials with the advantage of diversified structure, easy fabrication, high thermal stability, and tunable properties have garnered considerable attention. However, adequate and precise tuning over CPL in polymer-based materials remains challenging due to the difficulty in regulating chiral structures. Herein, visualized full-color CPL is achieved by doping red, green, and blue quantum dots (QDs) into reconfigurable blue phase liquid crystal elastomers (BPLCEs). In contrast to the CPL signal observed in cholesteric liquid crystal elastomers (CLCEs), the chiral 3D cubic superstructure of BPLCEs induces an opposite CPL signal. Notably, this effect is entirely independent of photonic bandgaps (PBGs) and results in a high glum value, even without matching between PBGs and the emission bands of QDs. Meanwhile, the lattice structure of the BPLCEs can be reversibly switched via mechanical stretching force, inducing on-off switching of the CPL signals, and these variations can be further fixed using dynamic disulfide bonds in the BPLCEs. Moreover, the smart polymer-based CPL systems using the BPLCEs for anti-counterfeiting and information encryption have been demonstrated, suggesting the great potential of the BPLCEs-based CPL active materials.

Accelerating Cellular Uptake with Unnatural Amino Acid for Inhibiting Immunosuppressive Cancer Cells

Targeting immunosuppressive metastatic cancer cells is a key challenge in therapy. We recently have shown that a rigid-rod aromatic, pBP-NBD, that responds to enzymes and kill immunosuppressive metastatic osteosarcoma (mOS) and castration resistant prostate cancer (CRPC) cells in mimetic bone microenvironment. However, pBP-NBD demonstrated moderate efficacy against CRPC cells. To enhance activity, we incorporated the unnatural amino acid L- or D-4,4'-biphenylalanine (L- or D-BiP) into pBP-NBD, drastically increasing cellular uptake and CRPC inhibition. Specifically, we inserted BiP into pBP-NBD to target mOS (Saos2 and SJSA1) and CRPC (VCaP and PC3) cells with overexpressed phosphatases. Our results show that the D-peptide backbone with an aspartate methyl diester at the C-terminal offers the highest activity against these immunosuppressive mOS and CRPC cells. Importantly, imaging shows that the peptide assemblies almost instantly enter the cells and accumulate primarily within the endoplasmic reticulum of Saos2, SJSA1, and PC3 cells and at the lysosomes of VCaP cells. By using BiP to boost cellular uptake and self-assembly within cancer cells, this work illustrates an unnatural hydrophobic amino acid as a versatile and effective residue to boost endocytosis of synthetic peptides for intracellular self-assembly.

Amplified Circularly Polarized Luminescence Behavior in Chiral Co-assembled Liquid Crystal Polymer Films via the Strategic Manipulation of Chiral Inducers

One of the most important factors for the future application of circularly polarized luminescence (CPL) materials is their high dissymmetry factors (gem), and more and more studies are working tirelessly to focus on increasing the gem value. Herein, we chose an achiral liquid crystal polymer (LC-P) and two chiral binaphthyl-based inducers (R/S-3 and R/S-6) with different substitution positions (3,3' positions for R/S-3 and 6,6' positions for R/S-6) to construct chiral co-assemblies and explored their induced amplification CPL behaviors. Interestingly, after the thermal annealing treatment, this kind of chiral co-assembly (R/S-3)0.05-(LC-P)0.95 can emit a superior CPL signal (|gem| = 0.31 and λem = 424 nm), which achieves about 13-fold signal amplification in the spin-coated film, compared to (R/S-6)0.1-(LC-P)0.9 (|gem| = 0.023 and λem = 424 nm). This is because (R/S-3)0.05-(LC-P)0.95 could further co-assemble to form a more ordered arrangement LC state and generate regular helix nanofibers than that of (R/S-6)0.1-(LC-P)0.9. This work provides an efficient method for synthesizing high-quality CPL-active materials through the strategic manipulation of the structure of chiral binaphthyl-based inducers in chiral co-assembled LCP systems.

Synthesis and Photophysical Properties of a Chiral Carbon Nanoring Containing Rubicene

Herein we report the construction of an inherently chiral carbon nanoring, cyclo[7]paraphenylene-2,9-rubicene ([7]CPPRu2,9), by combining rubicene with a C-shaped synthon through the Suzuki-Miyaura coupling reaction. The structure was fully confirmed by high-resolution mass spectroscopies (HR-MS) and various NMR techniques. The photophysical properties were investigated by UV-vis absorption and fluorescence spectroscopy as well as the time-resolved fluorescence decay. Moreover, two enantiomers (M)/(P)-[7]CPPRu2,9 were successfully resolved by recyclable HPLC and studied by CD and CPL spectra.

Construction of a pillar[5]arene-based supramolecular chiral polymer linked to aminophosphine salt for chiral recognition of enantiomers of mandelic acid

In recent years, supramolecular chirality has been greatly developed in asymmetric synthesis, chiral sensing and other research fields, but its application in molecular chiral recognition has not been extensively studied. In this paper, L-Boc-tyrosine methoxyester and phosphorus chloride salts were introduced into the framework of pillar[n]arene, and a pillar[5]arene-based supramolecular chiral polymer L-TPP-P was constructed. The supramolecular polymer had stable supramolecular chiral properties and could be used as a chiral solvation reagent for chiral recognition of mandelic acid MA. The molar ratio method and Scatchard plot showed that the complexation ratio of L-TPP-P (pillar[5]arene monomer as the reference object) and MA was 1 : 1, and the complexation constants of L-TPP-P with R-MA and S-MA were 4.51 × 105 M-1 and 6.5 × 104 M-1, respectively. The significant affinity difference of L-TPP-P for different enantiomers of MA showed the excellent chiral recognition and stereoselectivity of pillar[5]arene-based supramolecular polymers for MA. This study provides a new idea for a novel supramolecular polymer chiral recognition reagent or chiral recognition method.

Switchable supramolecular helices for asymmetric stereodivergent catalysis

Despite recent developments on the design of dynamic catalysts, none of them have been exploited for the in-situ control of multiple stereogenic centers in a single molecular scaffold. We report herein that it is possible to obtain in majority any amongst the four possible stereoisomers of an amino alcohol by means of a switchable asymmetric catalyst built on supramolecular helices. Hydrogen-bonded assemblies between a benzene-1,3,5-tricarboxamide (BTA) achiral phosphine ligand coordinated to copper and a chiral BTA comonomer are engaged in a copper-hydride catalyzed hydrosilylation and hydroamination cascade process. The nature of the product stereoisomer is related to the handedness of the helices and can thus be directed in a predictable way by changing the nature of the major enantiomer of the BTA comonomer present in the assemblies. The strategy allows all stereoisomers to be obtained one-pot with similar selectivities by conducting the cascade reaction in a concomitant manner, i.e. without inverting the handedness of the helices, or sequentially, i.e. by switching the handedness of the supramolecular helices between the hydrosilylation and hydroamination steps. Supramolecular helical catalysts appear as a unique and versatile platform to control the configuration of molecules or polymers embedding several stereogenic centers.

Ultrasensitive Solvatochirochromism of Single Benzene Chromophores

Solvents influence the structure, aggregation and folding behaviors of solvatochromic compounds. Ultrasensitive solvent mediated chiroptical response is conducive to the fabrication of molecular platform for sensing and recognition, which however, remains great challenges in conceptual or applicable design. Here we report a cysteine-based single benzene chromophore system that shows ultrasensitivity to solvents. Compared to the ratiometrically responsive systems, the chiroptical activities could be triggered or inverted depending on the substituents of chiral entities with an ultralow solvent volume fraction (<1 vol %). One drop of dipolar solvents shall significantly induce the emergence or inversion of chiroptical signals in bulky phases. Based on the experimental and computational studies, the ultrasensitivity is contributed to the intimate interplay between solvents and chiral compounds that anchors the specific chiral conformation. It illustrates that structurally simple organic compounds without aggregation or folding behaviors possess pronounced solvatochiroptical properties, which sheds light on the next-generation of chiroptical sensors and switches.

Temperature-Induced Sign Inversion of Circularly Polarized Luminescence of Binaphthyl-Bridged Tetrathiapyrenophanes

D2-symmetric (R)-binaphthyl-bridged pyrenophanes containing thioether bonds were synthesized. The pyrenophanes exhibited the temperature-induced sign inversion of circularly polarized luminescence (CPL) while maintaining the emission wavelength and reversibility. The Δglum value reached 0.02, and the FL quenching by heat was negligible. The sign inversion of CPL originates from the inversion of intramolecular excimer chirality associated with excitation dynamics. The two pyrenes form a kinetically trapped left-handed twist excimer at low temperatures, while they form a thermodynamically favored right-handed twist excimer at high temperatures. The thioether linkers can impart flexibility suitable for the inversion of chirality of the excimers.

Light-Driven Sign Inversion of Circularly Polarized Luminescence Enabled by Dichroism Modulation in Cholesteric Liquid Crystals

Stimuli-responsive circularly polarized luminescence (CPL) materials show great promise in applying information encryption and anticounterfeiting. Herein, light-driven CPL sign inversion is achieved by combining a photoresponsive achiral negative dichroic dye (KG) and a static achiral positive dichroic dye (NR) as dopants at the 0.5:0.5 weight ratio into the cholesteric liquid crystal (CLC) host. The side chains of KG undergo trans/cis isomerization after 365 nm UV light irradiation, leading to the dichroism (SF) decrease. The |glum| value of CLC doping with KG (CLC-KG) weakens from 0.67 to 0.28 in response to the order degree change. Taking advantage of its unique CPL response property, the light-driven CPL sign inversion is achieved (from -0.20/0.14 to 0.02/-0.04) by incorporating NR (0.5:0.5) into the CLC-KG with helical superstructure static. Based on the synergistic use of circular polarization and responsiveness state as cryptographic primitives, the multidimensional information encryption CLC system can be realized.

Reversible chirality inversion of an AuAgx-cysteine coordination polymer by pH change

Responsive chiral systems have attracted considerable attention, given their potential for diverse applications in biology, optoelectronics, photonics, and related fields. Here we show the reversible chirality inversion of an AuAgx-cysteine (AuAgx-cys) coordination polymer (CP) by pH changes. The polymer can be obtained by mixing HAuCl4 and AgNO3 with L-cysteine (or D-cysteine) in appropriate proportions in H2O (or other surfactant solutions). Circular dichroism (CD) spectrum is used to record the strong optical activity of the AuAg0.06-L-cys enantiomer (denoted as L0.06), which can be switched to that of the corresponding D0.06 enantiomer by alkalization (final dispersion pH > 13) and can be switched back after neutralization (final dispersion pH <8). Multiple structural changes at different pH values (≈9.6, ≈13) are observed through UV-Vis and CD spectral measurements, as well as other controlled experiments. Exploration of the CP synthesis kinetics suggests that the covalent bond formation is rapid and then the conformation of the CP materials would continuously evolve. The reaction stoichiometry investigation shows that the formation of CP materials with chirality inversion behavior requires the balancing between different coordination and polymerization processes. This study provides insights into the potential of inorganic stereochemistry in developing promising functional materials.

Photocontrolled chiroptical switch based on the self-assembly of azobenzene-bridged bis-tryptophan enantiomers

Chirality dynamic tuning plays fundamental roles in chemistry, material science and biological system. Herein, a pair of azobenzene-bridged bis-tryptophan enantiomers (Azo-di-d/l-Trp) were designed and synthesized via simple reactions. With the fuel of glucono-δ-lactone (GdL), releasing protons during its hydrolysis, the alkaline solution of Azo-di-d/l-Trp gradually self-assembled into contrast chiral helical structures and displayed magnitude and mirror image of circular dichroism (CD) signals. While the chiral helices converted to CD silent nanoparticles when the azobenzene moiety isomerized from trans- to cis-form under UV irradiation. More importantly, this chiroptical switch, displaying reversible interconversion between chiral amplification and silent, can be smartly controlled via photoirradiation at various wavelengths.

Circularly polarized luminescence and high photoluminescence quantum yields from rigid 5,10-dihydroindeno[2,1-a]indene and 2,2'-dialkoxy-1,1'-binaphthyl conjugates and copolymers

5,5,10,10-Tetramethyl-5,10-dihydroindeno[2,1-a]indene (COPV1(Me)) was installed into either the 3,3'- or 6,6'-positions of chiral 2,2'-dioctyloxy-1,1'-binaphthyl to afford 2 : 1 conjugates (monomeric compounds) and 1 : 1 copolymers. These compounds showed high photoluminescence quantum yields of >0.95 whilst also exhibiting circular dichroism (CD) and circularly polarized luminescence (CPL). The dissymmetry factors of CPL (gCPL) for the 3,3'- and 6,6'-monomeric compounds in THF were 6.6 × 10-4 and 3.3 × 10-4, respectively. The 3,3'-isomer has a higher g value than the 6,6'-isomer, which was attributed to the difference in the extent of π-conjugation and the angle between electronic and magnetic transition moments. The gCPL values of the 3,3'-linked and 6,6'-linked copolymers were 1.1 × 10-3 and 6.8 × 10-4, respectively. The structural rigidity of the COPV units is beneficial to achieve relatively high g values whilst maintaining a photoluminescence quantum yield that is close to unity by using a single type of fluorophore.

Multiple hydrogen bonding driven supramolecular architectures and their biomedical applications

Supramolecular chemistry combines the strength of molecular assembly via various molecular interactions. Hydrogen bonding facilitated self-assembly with the advantages of directionality, specificity, reversibility, and strength is a promising approach for constructing advanced supramolecules. There are still some challenges in hydrogen bonding based supramolecular polymers, such as complexity originating from tautomerism of the molecular building modules, the assembly process, and structure versatility of building blocks. In this review, examples are selected to give insights into multiple hydrogen bonding driven emerging supramolecular architectures. We focus on chiral supramolecular assemblies, multiple hydrogen bonding modules as stimuli responsive sources, interpenetrating polymer networks, multiple hydrogen bonding assisted organic frameworks, supramolecular adhesives, energy dissipators, and quantitative analysis of nano-adhesion. The applications in biomedical materials are focused with detailed examples including drug design evolution for myotonic dystrophy, molecular assembly for advanced drug delivery, an indicator displacement strategy for DNA detection, tissue engineering, and self-assembly complexes as gene delivery vectors for gene transfection. In addition, insights into the current challenges and future perspectives of this field to propel the development of multiple hydrogen bonding facilitated supramolecular materials are proposed.

P/M Macromolecular Switch Based on Conformational Control Exerted by an Achiral Side Chain within an Axially Chiral Locked Pendant

Molecular switches, supramolecular chemistry, and polymers can be combined to create stimuli-responsive multichiral materials. Therefore, by acting on the extended/bent conformational composition of an achiral arm, it is possible to create a macromolecular gear, where different supramolecular interactions can be activated/deactivated to control the helical sense of a polymer containing up to five different chiral axial motifs. For this, a chiral allene with a flexible achiral arm was introduced as a pendant in poly(phenylacetylene). Through flexible arm control between extended and bent conformations, it is possible to selectively induce either a P or M helical sense in the polymer, while the relative spatial distribution of the substituents in the allene remains unaltered in two perpendicular planes (configurationally locked). These results show that complex dynamic multichiral materials can be obtained by the polymerization of appropriate monomers that combine chirality, switching properties, and the ability to generate chiral supramolecular assemblies.

Enhancing the Circularly Polarized Luminescence of Europium Coordination Polymers by Doping a Chromophore Ligand into Superhelices

Lanthanide-based molecular materials showing efficient circularly polarized luminescence (CPL) activity with a high quantum yield are attractive due to their potential applications in data storage, optical sensors, and 3D displays. Herein we present an innovative method to achieve enhanced CPL activity and a high quantum yield by doping a chromophore ligand into a coordination polymer superhelix. A series of homochiral europium(III) phosphonates with a helical morphology were prepared with the molecular formula S-, R-[Eu(cyampH)3-3n(nempH)3n]·3H2O (S/R-Eu-n, n = 0-5%). The doping of chromophore ligand S- or R-nempH2 into superhelices of S/R-Eu-0% not only turned on the CPL activity with the dissymmetry factor |glum| on the order of 10-3 but also increased the quantum yield by about 14-fold. This work may shed light on the development of efficient CPL-active lanthanide-based coordination polymers for applications.

Modulation of the assembly fashion among metal-organic frameworks for enantioretentive epoxide activation

Highly enantioretentive alcoholysis of epoxides is an important way to synthesize enantiopure β-alkoxy alcohols, which are irreplaceable intermediates demanded by biomedicines, fine chemicals and other industries. In this report, we exploit a series of Zr-based metal-organic frameworks (Zr-MOFs) as the catalysts to achieve high activity and enantioretentivity in the alcoholysis of styrene oxide via modulating their assembly fashions. It is explored that hcp-UiO-66 not only exhibits a ∼10 fold improved catalytic activity than both hxl-CAU-26 and fcc-UiO-66 of varied assemblies but also maintains superior product enantioretentivity. Theoretic calculations together with experimental proof discloses the origin of distinct catalytic activity caused by different assembly fashions. This assembly modulation strategy offers a potential protocol for seeking high-performance catalysts among MOFs by virtue of their rich polymorphisms.

Substituent alkyl-chain-dependent supramolecular chirality, tunable chiroptical property, and dye adsorption in azobenzene-glutamide-amphiphile based hydrogel

Controlling the supramolecular chirality of a self-assembly system by molecular structure design and external stimuli in aqueous solution is significant but challenging. Here, we design and synthesize several glutamide-azobenzene-based amphiphiles with different length alkyl chains. The amphiphiles can form self-assemblies in aqueous solution and show CD signals. As the number of the alkyl chain of amphiphiles increases, the CD signals of the assemblies can be enhanced. However, the long alkyl chains conversely restrict the isomerization of the azobenzene and the corresponding chiroptical property. Moreover, the alkyl length can determine the nanostructure of the assemblies and exert critical influence on the dye adsorption efficiency. This work exhibits some insights into the tunable chiroptical property of the self-assembly by delicate molecular design and external stimuli, and emphasizes the molecular structure can determine the corresponding application.

Platinum(II) terpyridine-based supramolecular polymer gels with induced chirality

Metal-ligand binding plays a crucial role in regulating the photophysical properties of supramolecular gels. In this study, we designed 1-Pt complexes comprising a central benzene-1,3,5-tricarboxamide unit functionalized with three terpyridines, which can form supramolecular gels with Pt(II). The resulting supramolecular gel of 1-Pt exhibited strong orange emission, which was attributed to the metal-to-metal ligand charge transfer during gel formation. Furthermore, the temperature-dependent absorption spectrum changes of the supramolecular polymer 1-Pt exhibited a nonsigmoidal transition, following a cooperative pathway involving a nucleation-elongation mechanism. Additionally, the strategy for the co-assembling system involving 1-Pt with chiral molecules (D-form and L-form) induced the helical arrangement of 1-Ptvia chiral additives in supramolecular metallogels.

Parallel Chirality Inductions in Möbius Zn(II) Hexaphyrin Transformation Networks

Networked chemical transformations are key features of biological systems, in which complex multicomponent interactions enable the emergence of sophisticated functions. Being interested in chirality induction phenomena with dynamic Möbius π-systems, we have designed a pair of Möbius [28]hexaphyrin ligands in order to investigate mixtures rather than isolated molecules. Thus, a hexaphyrin bearing a chiral amino arm was first optimized and found to bind a ZnOAc moiety, triggering an impressive quasi-quantitative chirality induction over the Möbius π-system. Second, this amino-type hexaphyrin was mixed with a second hexaphyrin bearing a chiral carboxylate arm, affording at first ill-defined coordination assemblies in the presence of zinc. In contrast, a social self-sorting behavior occurred upon the addition of two exogenous achiral effectors (AcO- and BuNH2), leading to a well-defined 1:1 mixture of two Möbius complexes featuring a sole Möbius twist configuration (parallel chirality inductions). We next successfully achieved compartmentalized switching, i.e., a single-component transformation from such a complex mixture. The BuNH2 effector was selectively protected with Boc2O, owing to a lower reactivity of the arm's NH2 function intramolecularly bound to zinc, and subsequent addition of BuNH2 restored the initial mixture, retaining parallel chirality inductions (five cycles). By changing the nature and twist configuration of only one of the two complexes, at initial state or by switching, this approach enables a "two-channel" tuning of the chiroptical properties of the ensemble. Such multiple dynamic chirality inductions, controlled by selective metal-ligand recognition and chemical reactivity, set down the basis for Möbius-type stereoselective transformation networks with new functions.

Enabling Stereochemical Communication and Stimuli-Responsive Chiroptical Properties in Biphenyl-Capped Cyclodextrins

Chiroptical materials are gaining increasing interest due to their innovative character and their applications in optoelectronics and data encryption technologies. Fully harnessing the potential of building blocks from the "chiral pool", such as native cyclodextrins (CDs), as they often lack chromophores suitable for the construction of materials with significant chiroptical properties. Here, we present the synthesis and characterization of a two-level molecular stack consisting of a point-chiral element (CD) and an axially chiral element (biphenyl), capable of effectively translating the overall stereochemical information contained in CDs into stimuli-responsive chiroptical properties. α- and β-permethylated CDs were efficiently capped with two different 2,2'-difunctionalized 1,1'-biphenyl units. In CD derivatives containing the rigid 2,2'-dihydroxy-1,1'-biphenyl cap, two intramolecular hydrogen bonds act synergistically as stereoselective actuators, enabling effective communication between the two levels and the transfer of nonchromophoric stereochemical information from the cyclic-oligosaccharide to the atropoisomeric cap. The chiroptical properties can be finely tuned by external stimuli such as temperature and solvent. The way chirality is transferred from the CD platform to the biphenyl cap was revealed thanks to crystallographic and computational analyses, together with electronic circular dichroism (ECD) studies.

Nature-Inspired Chiral Structures: Fabrication Methods and Multifaceted Applications

Diverse chiral structures observed in nature find applications across various domains, including engineering, chemistry, and medicine. Particularly notable is the optical activity inherent in chiral structures, which has emerged prominently in the field of optics. This phenomenon has led to a wide range of applications, encompassing optical components, catalysts, sensors, and therapeutic interventions. This review summarizes the imitations and applications of naturally occurring chiral structures. Methods for replicating chiral architectures found in nature have evolved with specific research goals. This review primarily focuses on a top-down approach and provides a summary of recent research advancements. In the latter part of this review, we will engage in discussions regarding the diverse array of applications resulting from imitating chiral structures, from the optical activity in photonic crystals to applications spanning light-emitting devices. Furthermore, we will delve into the applications of biorecognition and therapeutic methodologies, comprehensively examining and deliberating upon the multifaceted utility of chiral structures.

In Situ Photoisomerization of an Azobenzene-Based Triple Helicate with a Prolonged Thermal Relaxation Time

The phosphate-coordination triple helicates A2 L3 (A=anion) with azobenzene-spaced bis-bis(urea) ligands (L) have proven to undergo a rare in situ photoisomerization (without disassembly of the structure) rather than the typically known, stepwise "disassembly-isomerization-reassembly" process. This is enabled by the structural self-adaptability of the "aniono" assembly arising from multiple relatively weak and flexible hydrogen bonds between the phosphate anion and bis(urea) units. Notably, the Z→E thermal relaxation rate of the isomerized azobenzene unit is significantly decreased (up to 20-fold) for the triple helicates compared to the free ligands. Moreover, the binding of chiral guest cations inside the cavity of the Z-isomerized triple helicate can induce optically pure diastereomers, thus demonstrating a new strategy for making light-activated chiroptical materials.

A Smart Single-Fluorophore Polymer: Self-Assembly Shapechromic Multicolor Fluorescence and Erasable Ink

A novel smart fluorescent polymer polyethyleneimine-grafted pyrene (PGP) is developed by incorporating four stimuli-triggers at molecular level. The triggers are amphiphilicity, supramolecular host-guest sites, pyrene fluorescence indicator, and reversible chelation sites. PGP exhibits smart deformation and shape-dependent fluorescence in response to external stimuli. It can deform into three typical shapes with a characteristic fluorescence color, namely, spherical core-shell micelles of cyan-green fluorescence, standard rectangular nanosheets of yellow fluorescence, and irregular branches of deep-blue fluorescence. A quasi-reversible deformation between the first two shapes can be dynamically manipulated. Moreover, driven by reversible coordination and the resulting intramolecular photoinduced electron transfer, PGP can be used as an aqueous fluorescence ink with erasable and recoverable properties. The fluorescent patterns printed by PGP ink on paper can be rapidly erased and recovered by simple spraying a sequence of Cu2+ and ethylene diamine tetraacetic acid aqueous solutions. This erase/recover transformation can be repeated multiple times on the same paper. The multiple stimulus responsiveness of PGP makes it have potential applications in nanorobots, sensing, information encryption, and anticounterfeiting.

Macroscopic handedness inversion of terbium coordination polymers achieved by doping homochiral ligand analogues

Inspired by natural biological systems, chiral or handedness inversion by altering external and internal conditions to influence intermolecular interactions is an attractive topic for regulating chiral self-assembled materials. For coordination polymers, the regulation of their helical handedness remains little reported compared to polymers and supramolecules. In this work, we choose the chiral ligands R-pempH2 (pempH2 = (1-phenylethylamino)methylphosphonic acid) and R-XpempH2 (X = F, Cl, Br) as the second ligand, which can introduce C-H⋯π and C-H⋯X interactions, doped into the reaction system of the Tb(R-cyampH)3·3H2O (cyampH2 = (1-cyclohexylethylamino)methylphosphonic acid) coordination polymer, which itself can form a right-handed superhelix by van der Waals forces, and a series of superhelices R-1H-x, R-2F-x, R-3Cl-x, and R-4Br-x with different doping ratios x were obtained, whose handedness is related to the second ligand and its doping ratio, indicating the decisive role of interchain interactions of different strengths in the helical handedness. This study could provide a new pathway for the design and self-assembly of chiral materials with controllable handedness and help the further understanding of the mechanism of self-assembly of coordination polymers forming macroscopic helical systems.

Chiroptical switching in the azobenzene-based self-locked [1]rotaxane by solvent and photoirradiation

Because of its dynamic reversible nature and simple regulation properties, rotaxane systems provided a good route for the construction of responsive supramolecular chiral materials. Here, we covalently encapsulate the photo-responsive guest molecule azobenzene (Azo) in a chiral macrocycle β-cyclodextrin (β-CD) to prepare self-locked chiral [1]rotaxane [Azo-CD]. On this basis, the self-adaptive conformation of [Azo-CD] was manipulated by solvent and photoirradiation; meanwhile, dual orthogonal regulation of the [1]rotaxane chiroptical switching could also be realized.

Dual-Responsive Fe3O4@Polyaniline Chiral Superstructures for Information Encryption

Incorporating stimuli-responsive mechanisms into chiral assemblies of nanostructures offers numerous opportunities to create optical materials capable of dynamically modulating their chiroptical properties. In this study, we demonstrate the formation of chiral superstructures by assembling Fe3O4@polyaniline hybrid nanorods by using a gradient magnetic field. The resulting superstructures exhibit a dual response to changes in both the magnetic field and solution pH, enabling dynamic regulation of the position, intensity, and sign of its circular dichroism peaks. Such responsiveness allows for convenient control over the optical rotatory dispersion properties of the assemblies, which are further integrated into the design of a chiroptical switch that can display various colors and patterns when illuminated with light of different wavelengths and polarization states. Finally, an optical information encryption system is constructed through the controlled assembly of the hybrid nanorods to showcase the potential opportunities for practical applications brought by the resulting responsive chiral superstructures.

Electron spin polarization in supramolecular polymers with complex pathways

Mastering the manipulation of the electron spin plays a crucial role in comprehending the behavior of organic materials in several applications, such as asymmetric catalysis, chiroptical switches, and electronic devices. A promising avenue for achieving such precise control lies in the Chiral Induced Spin Selectivity (CISS) effect, where electrons with a favored spin exhibit preferential transport through chiral assemblies of specific handedness. Chiral supramolecular polymers emerge as excellent candidates for exploring the CISS effect due to their ability to modulate their helical structure through noncovalent interactions. In this context, systems capable of responding to external stimuli are particularly intriguing, sometimes even displaying chirality inversion. This study unveils spin selectivity in chiral supramolecular polymers, derived from single enantiomers, through scanning tunneling microscopy conducted in scanning tunneling spectroscopy mode. Following two distinct sample preparation protocols for each enantiomer, we generate supramolecular polymers with opposite handedness and specific spin transport characteristics. Our primary focus centers on chiral π-conjugated building blocks, with the aim of advancing novel systems that can inspire the organic spintronics community from a supramolecular chemistry level.

Logical gates in ensembles of proteinoid microspheres

Proteinoids are thermal proteins which swell into microspheres in aqueous solution. Ensembles of proteinoids produce electrical spiking activity similar to that of neurons. We introduce a novel method for implementing logical gates in the ensembles of proteinoid microspheres using chronoamperometry. Chronoamperometry is a technique that involves applying a voltage pulse to proteinoid microspheres and measuring their current response. We have observed that proteinoids exhibit distinct current patterns that align with various logical outputs. We identify four types of logical gates: AND, OR, XOR, and NAND. These gates are determined by the current response of proteinoid microspheres. Additionally, we demonstrate that proteinoid microspheres have the ability to modify their current response over time, which is influenced by their previous exposure to voltage. This indicates that they possess a capacity for learning and are capable of adapting to their environment. Our research showcases the ability of proteinoid microspheres to perform logical operations and computations through their inherent electrical properties.