Metallophilic Interaction-Mediated Hierarchical Assembly and Temporal-Controlled Dynamic Chirality Inversion of Metal-Organic Supramolecular Polymers

Chirality-enhanced 2D conductive polymer for flexible electronics and chiral sensing applications

Chiral two-dimensional (2D) conductive polymers, encompassing chiral, 2D, flexible, and conductive properties, constitute a novel class of material that remains largely unexplored. The infusion of chirality into 2D conductive polymers taps into the unique characteristics associated with chirality, presenting opportunities to enhance or tailor the electronic, optical, and structural properties of materials for specific technological applications. In this study, we synthesized a chiral 2D PEDOT:PMo11V nanofilm through interfacial polymerization, effectively integrating a chiral monolayer, conductive polymer, and inorganic cluster. The inclusion of inorganic cluster serves to enhance the conductivity of the resulting chiral nanofilm. Furthermore, we demonstrated the chiral nanofilm as a capable electrochemical sensor for detecting drug enantiomers. The inherent flexibility of the chiral nanofilm also lays the groundwork for the development of chiral flexible/wearable devices.

pH-Modulated 1D Hierarchical Self-Assembly of a Brush-Like Poly-Para-Phenylene Homopolymer

The controllable self-assembly of conjugated homopolymers, especially homopolymers without other segments (a prerequisite for phase separation), which can afford chances to achieve tunable optical/electronic properties, remains a great challenge due to their poor solubility and has remained rarely documented. Herein, a conjugated homopolymer (DPPP-COOH) is synthesized, which has a unique brush-like structure with a conjugated dendritic poly-para-phenylene (DPPP) backbone and alkyl-carboxyl side chains at both edges of the backbone. The introduction of carboxyl makes the brush-like homopolymer exhibit pH-modulated 1D hierarchical self-assembly behavior in dilute solution, and allows for flexible morphological regulation of the assemblies, forming some uncommon superstructures including ultralong nanowires (at pH 7), superhelices (at pH 10) and "single-wall" nanotubes (at pH 13), respectively. Furthermore, the good aqueous dispersibility and 1D feature endow the superstructures formed in a high-concentration neutral solution with high broad-spectrum antibacterial performance superior to that of many conventional 1D materials.

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.

An Encyclopedic Compendium on Chemosensing Supramolecular Metal-Organic Gels

Chemosensing, an interdisciplinary scientific domain, plays a pivotal role ranging from environmental monitoring to healthcare diagnostics and (inter)national security. Metal-organic gels (MOGs) are recognized for their stability, selectivity, and responsiveness, making them valuable for chemosensing applications. Researchers have explored the development of MOGs based on different metal ions and ligands, allowing for tailored properties and sensitivities, and have even demonstrated their applications as portable sensors such as paper-based test strips for practical use. Herein, several studies related to MOGs development and their applications in the chemosensing field via UV-visible or luminance along with electrochemical approach are presented. These papers explored MOGs as versatile materials with their use in sensing bio or environmental analytes. This review provides a foundational understanding of key concepts, methodologies, and recent advancements in this field, fostering the scientific community.

Biomimetic Chiral Nanomaterials with Selective Catalysis Activity

Chiral nanomaterials with unique chiral configurations and biocompatible ligands have been booming over the past decade for their interesting chiroptical effect, unique catalytical activity, and related bioapplications. The catalytic activity and selectivity of chiral nanomaterials have emerged as important topics, that can be potentially controlled and optimized by the rational biochemical design of nanomaterials. In this review, chiral nanomaterials synthesis, composition, and catalytic performances of different biohybrid chiral nanomaterials are discussed. The construction of chiral nanomaterials with multiscale chiral geometries along with the underlying principles for enhancing chiroptical responses are highlighted. Various biochemical approaches to regulate the selectivity and catalytic activity of chiral nanomaterials for biocatalysis are also summarized. Furthermore, attention is paid to specific chiral ligands, materials compositions, structure characteristics, and so on for introducing selective catalytic activities of representative chiral nanomaterials, with emphasis on substrates including small molecules, biological macromolecule, and in-site catalysis in living systems. Promising progress has also been emphasized in chiral nanomaterials featuring structural versatility and improved chiral responses that gave rise to unprecedented chances to utilize light for biocatalytic applications. In summary, the challenges, future trends, and prospects associated with chiral nanomaterials for catalysis are comprehensively proposed.

Photoisomerization and thermal reconstruction induced supramolecular chirality inversion in nanofiber determined by minority isomer

Here, amphiphile GCH based on glutamide-cyanostilbene is designed and synthesized, it is found that it can assembly in acetonitrile, and shows circular dichroism signals. After Z-E isomerizaition by UV irradiation, the CD signal of the assembly can be inverted. Unexpectedly, after another heating and cooling process, the circular dichroism signals can be totally inverted even though the E-isomers are in minority. Finally, the molecular dynamics (MD) simulations deeply elucidate the supramolecuar chirality inversion mechanism. This work brings some new insights into the control of chirality inversion, which may provide a perspective for the smart chiroptical materials construction.

Achiral substituent- and stoichiometry-controlled inversion of supramolecular chirality and circularly polarized luminescence in ternary co-assemblies

Handedness inversion of supramolecular chirality and circularly polarized luminescence (CPL) in assembled systems containing more than two components with higher complexity is of prominent importance to simulate biological multicomponent species and design advanced chiral materials, but it remains a considerable challenge. Herein, we have successfully developed ternary co-assembly systems based on aromatic amino acids, vinylnaphthalene derivatives and 1,2,4,5-tetracyanobenzene with effective chirality transfer. Notably, the handedness of supramolecular chirality and CPL can be readily inverted by changing the residues of amino acids, the substituents of achiral vinylnaphthalene derivatives, or by adjusting the stoichiometric ratio. The hydrogen bonds, charge transfer interactions, and steric hindrance are proved to be the crucial factors for the chirality inversion. This flexible control over chirality not only offers insights into developing multicomponent chiral materials with desirable handedness from simple molecular building blocks, but also is of practical value for use in chiroptics, chiral sensing, and photoelectric devices.

Hierarchical Self-Assembly Molecular Building Blocks as Intelligent Nanoplatforms for Ovarian Cancer Theranostics

Hierarchical self-assembly from simple building blocks to complex polymers is a feasible approach to constructing multi-functional smart materials. However, the polymerization process of polymers often involves challenges such as the design of building blocks and the drive of external energy. Here, a hierarchical self-assembly with self-driven and energy conversion capabilities based on p-aminophenol and diethylenetriamine building blocks is reported. Through β-galactosidase (β-Gal) specific activation to the self-assembly, the intelligent assemblies (oligomer and superpolymer) with excellent photothermal and fluorescent properties are dynamically formed in situ, and thus the sensitive multi-mode detection of β-Gal activity is realized. Based on the overexpression of β-Gal in ovarian cancer cells, the self-assembly superpolymer is specifically generated in SKOV-3 cells to achieve fluorescence imaging. The photothermal therapeutic ability of the self-assembly oligomer (synthesized in vitro) is evaluated by a subcutaneous ovarian cancer model, showing satisfactory anti-tumor effects. This work expands the construction of intelligent assemblies through the self-driven cascade assembly of small molecules and provides new methods for the diagnosis and treatment of ovarian cancer.

Self-Assembly of Functionalized Twistarenes into Supramolecular Assemblies with Chiroptical Property and Photoconductive Behavior

A pair of novel chiral 1-phenylethylamine-modified twistarenes (4 and 11; compound 4 = 9,14-di-tert-butyl-7,16-diphenyl-2-(1-phenylethyl)-1H-benzo[8',9']triphenyleno[2',3':6,7]fluoreno[2,1,9-def]isoquinoline-1,3(2H)-dione) have been synthesized and characterized, and how the solvent component affects the chirality transfer of their self-assembled processes is investigated in mixtures with THF and H2O. The ordered assembly of 11 exhibits circular dichroism response. In addition, both 11a and 11b display positive photoconducting behavior.

Full-Color Circularly Polarized Luminescence of Supramolecular Polymers with Handedness Inversion Regulated by Anion and Temperature

Constructing full-color circularly polarized luminescence (CPL) materials with switchable handedness in the solid state is an appealing yet considerably challenging task, especially for supramolecular polymer films assembled from homochiral monomers. Herein, supramolecular polymers with full-color CPL and inverted handedness are realized through the coassembly of a homochiral cholesterol derivative (PVPCC), metal ions (Zn2+), and achiral fluorescent dyes. The obtained coassembled systems show anion-directed supramolecular chirality inversion by exchanging the anions of NO3-, ClO4-, BF4-, and Cl-. For instance, the negative CD and right-handed CPL are detected in the PVPCC/Zn(NO3)2 aggregates, which convert into positive CD and left-handed CPL after introducing Cl-, corresponding to the transformation from nanorods to nanofibers. Furthermore, the tunable CPL color and handedness inversion of the coassembly system of PVPCC/Zn(NO3)2 and achiral fluorescent dyes can be established by alternately changing the assembling temperature of 298 and 273 K. Importantly, the full-color CPL polymeric materials are then constructed by doping the PVPCC/Zn(NO3)2/dyes complexes into poly(methyl methacrylate) (PMMA) film, which maintains the handedness inversion and shows the enhanced CPL performance. The work not only deepens the understanding of chirality inversion in supramolecular chemistry but also helps to construct full-color CPL materials with switchable handedness from homochiral building blocks in materials science.

Multicolor circularly polarized luminescence inversion of metal-organic supramolecular polymers

Metal-organic supramolecular polymers (MOSPs) with multicolor circularly polarized luminescence (CPL) and handedness inversion were constructed from the coordination-driven assembly of pyridine-cyanostilbene-cholesterol and metal salts by modulating the treatment modes, solvents, and metal ions.

Polymer-Enabled Assembly of Au Nanoclusters with Luminescence Enhancement and Macroscopic Chirality

The construction of macroscopic chiral luminescent aggregates with well-defined structures not only contributes to the development of functional materials but also has significant implications for analyzing chiral transfer and amplification in biological systems and self-assembly systems. Meanwhile, achieving water-soluble chiral metal nanoclusters (NCs) with high photoluminescence (PL) intensity through a convenient method remains a challenge. Herein, we reported the enhanced luminescence of gold nanoclusters stabilized by D-/L-penicillamine (D-/L-AuNCs) induced by poly(allylamine hydrochloride) (PAH) through supramolecular self-assembly strategies. FT-IR spectra and zeta potential measurements revealed that supramolecular assembly was driven by the synergistic effect of hydrogen bonds and electrostatic interactions, which effectively limited the intramolecular vibration and rotation of the ligand and reduced nonradiative relaxation, thus improving the luminescence properties of nanoclusters. Interestingly, during the slow solvent evaporation process, chiral entanglement of assemblies was enhanced, forming macroscopic wheat-shaped superstructures. This study enriches the understanding of the self-assembly mechanism of nanoclusters and provides a pathway for constructing NC-based chiroptical materials.

Solvent-Directed Hierarchical Self-Assembly of Tetraphenylpyrazine-Cholesterol with Amplified Circularly Polarized Luminescence

It is important to identify the effect of assembly and aggregation on the chirality transfer and energy transmission in supramolecular polymer system, since the unordered aggregation is insufficient to promote luminescence enhancement and chirality transfer, even causing the negative effect. Another key issue is to identify the solvent effect on hierarchically chiral self-assembly. Herein, we designed an AIE-core based building block, tetraphenylpyrazine-cholesterol (TPP-Chol), to explore how the solvent component influences chirality transfer and energy transmission of its aggregates and/or assemblies. Interestingly, the hierarchical assembly behavior was realized in the mixture of MeOH/CHCl3 highly dependent on the MeOH content. During the solvent-directed hierarchical assembly, the morphologic transformations, such as nanoribbons with a width of 150 nm, twisted nanoribbons with helical pitch of 420 nm, nanoribbon clusters, and microflowers with an average diameter of 5.5 μm, were realized with obvious chirality amplification for both circular dichroism (CD) and circularly polarized luminescence (CPL) measurements. The hierarchical assembly of TPP-Chol was also demonstrated by a time-dependent CD test. The work points out the complexity and dynamic of hierarchically chiral self-assembly regulated by the solvent effect, which would be helpful for the development of supramolecular materials with enhanced CPL performance and dynamic chirality.

Cascade energy transfer boosted near-infrared circularly polarized luminescence of nanofibers from an exclusively achiral system

We constructed chiral supramolecular nanofibers for light harvesting based on symmetry-breaking, and these can generate near-infrared circularly polarized luminescence (CPL) with high dissymmetry factor (g_lum) through a synergistic energy transfer and chirality transfer process. Firstly, the achiral molecule BTABA was assembled into a symmetry-breaking assembly using a seeded vortex strategy. Subsequently, the chiral assembly can endow the two achiral acceptors, Nile Red (NR) and Cyanine 7 (CY7), with supramolecular chirality, as well as chiroptical properties. CY7 can reach an excited state and emit near-infrared light through a cascade energy transfer process from BTABA to NR and then to CY7, but cannot directly acquire energy from the excited BTABA. Significantly, the near-infrared CPL of CY7 can be obtained with a boosted g_lum value of 0.03. This work will provide a deep insight into the preparation of materials with near-infrared CPL activity from an exclusively achiral system.