Regulation and application of supramolecular gel with circularly polarized luminescence

Supermolecular gel is a three-dimensional network structure assembled by small molecules or polymers in solvents through noncovalent interaction.The emergence of system complexity occurs spontaneously during the molecular self-assembly process.A multitude of chiral molecular self-assembly systems have been engineered,facilitating the achievement of circularly polarized luminescence(CPL)through the amalgamation of chiral entities with fluorophores.Hydrogen bonding,π-πstacking,and noncovalent forces,such as host-guest interactions and Van der Waals'forces,confer upon supramolecular gels the capacity to react to diverse stimuli.Due to the flexibility of supramolecular assembly,the CPL properties of supramolecular gels have rich controllability and can be used in various applications.In this review,we summarized the examples of CPL-active supramolecular gel assembly,and further summarized the assembly environment factors and external stimuli.Furthermore,the versatility of CPL applications in supramolecular gels is demonstrated,ranging from optical devices,information encryption,biosensing and chemical sensing,and other practical applications.In conclusion,the study provides insights into the multicultural factors influencing CPL in supramolecular gels,describes their applications in various domains,and presents future perspectives in the field.

Organoboron luminophores with extremely strong dual-phase emissions

Developing efficient dual-phase emission emitters upon organoboron luminophores remains a formidable challenge due to the ubiquitous self-absorption and deleterious π-π interactions from aromatic structure.Here, a new family of benzothiazole-enolate-based organoboron luminophores(HN1-4) with effective dual-phase emission was constructed. HN4 showed almost the highest quantum yield(QY) among this type of compound so far. The three-ring-fused rigid skeleton and moderate intramolecular charge transfer(ICT) effect ensured that HN4 could give rise to extremely strong emission in any solution(QY up to 99%). X-ray crystallographic analysis showed that the twisted core structure constructed by the boronic coordination of two penta-fluorobenzene of HN4 was responsible for intense emission in the solid state(QY up to 68%). Besides, HN4 exhibited a unique response to mechanical force accompanied by a reversible change of the QY. We believe that this strategy provides beneficial inspiration and methodology to design materials with high emissive quantum yield that can be used in a variety of luminescent events.

Luminescent properties and recent progress in applications of lanthanide metal-organic frameworks

Lanthanide metal-organic frameworks(Ln-MOFs), which is composed of organic bridging ligands and Ln3+ions/clusters, is an important component of luminescent MOFs. Compared with transition metal ions,lanthanide ions have a higher coordination number and abundant coordination geometry. Moreover, LnMOFs have special characteristics such as good porosity, topological diversity, high surface area and highly adjustable structure. The energy transfer(ET) process in Ln-MOFs could be easily affected by the interaction between host framework and guest, resulting in the change of luminescence intensity or color. Over the past few decades, the features of Ln-MOFs open the door to a range of incredibly important applications. However, there are few reviews on systemic summary of the various applications of Ln-MOFs. In this paper, we summarized the latest progress of Ln-MOFs applications, including the Ln-MOFs in chemical and biological sensors, optical information devices and catalysis, respectively, and discussed design mechanism. The possible problems in current research are briefly prospected, hoping to provide some helpful guidance for the future development of Ln-MOF materials.

Achieving purely organic room temperature phosphorescence in aqueous solution

Purely organic room temperature phosphorescence(RTP)materials have aroused increasing interests in recent years and have been widely applied in anticounterfeiting,biological imaging,sensing,etc.Currently,these materials can be efficiently developed in crystalline states and amorphous polymer-doped systems.However,achieving organic RTP in solution,especially in water solution,is still a formidable challenge.Recently,reports on aqueous phase RTP have been increasing and some feasible design strategies have been proposed;however,related investigations are still limited and there is a lack of systematic reviews.Therefore,we summarized the recent cases of aqueous phase organic RTP emission with primarily focusing on the RTP properties and efficient design strategies(e.g.,forming nanoparticles from phosphorescent molecules and macrocyclic supramolecular assembly).Moreover,promising applications of the aqueous phase organic RTP emission in bio-imaging and sensing were discussed.Some detailed perspectives concerning materials design and application were provided with the hope to provide inspiration for the future development of aqueous phase organic RTP.

Au(Ⅰ)-BSA nanocomposites with assembling-induced excitation-dependent multicolor emission for dynamic cell imaging

Excitation wavelength dependent(Ex-De) luminescent materials have attracted intense attention due to their great potential in multicolor bioimaging,dynamic anti-counterfeiting,and light emitting devices.However,it remains a formidable challenge to construct an Ex-De luminescent biomaterial with green starting materials,excellent biocompatibility,good water solubility,and multiple color emission for dynamic cell imaging.In this work,nanocomposites based on the facile self-assembly strategy of bovine serum albumin(BSA) and Au(Ⅰ)-complex are rationally designed and synthesized to simultaneously present Ex-De fluorescence(429–516 nm) and decent phosphorescence(~615 nm) in a dilute aqueous solution.Combinatory analyses of spectroscopic and microscopic results reveal that the luminescent mechanism of Au(Ⅰ)-BSA nanocomposites is cluster-induced Ex-De fluorescence and metal-to-ligand charge transition(MLCT) based phosphorescence.Importantly,based on the excellent biocompatibility,water-solubility and color-tunable emission over the entire visible region(360–800 nm),the Au(Ⅰ)-BSA nanocomposites are successfully used for cell imaging with multiple and switchable colors on demand.What is more,the solid tablets of Au(Ⅰ)-BSA nanoparticles showed pressure-responsive luminescence and decent room temperature phosphorescence.This work provides an assembling-induced emission strategy for the design of water-soluble,non-cytotoxic,and color-tunable luminescent biomaterials based on the composite of protein and Au nanoparticles.

Chitin oligosaccharides for the food industry:production and applications

Chitin oligosaccharides(CHOS),high-value-added oligomers linked by N-acetyl-d-glucosamine(GlcNAc,NAG),and a small amount of d-glucosamine(GlcN,GA),have aroused increasing interest due to their excellent biological properties,including antibacterial,anti-inflammatory,and immunoprotective activities,and intestinal regulation.The efficient production and utilization of CHOS with high performance can solve problems from chitin as biowaste.However,the large-scale production of well-defined CHOS has not been fully accomplished due to the limited biotechnology and separation methods,thus impeding the research on their biological functions as well as their accurate applications.In this review,we comprehensively summarize the current preparation methods of CHOS,including the chemical,physical,enzymatic and biosynthetic methods.The advantages and disadvantages of the methods are discussed in terms of efficiency,economy,and environmental effects.Furthermore,the applications of CHOS in the food industry and their contributions to human health based on their excellent bioactivities are expounded.It is hoped that this review will help in providing new insights into the production of CHOS with high precision,and support the application of CHOS in serving the food industry as nutritional supplements or foods for special medical purposes.

Magnetostrictive properties and detection efficiency of TbDyFe/FeCo composite materials for nondestructive testing

In order to develop a highly sensitive material for nondestructive testing(NDT),(Tb_(0.3) Dy_(0.7))Fe_(1.95) thin films were deposited on FeCo substrates at room temperature by magnetron sputtering and annealed.The magnetostrictive properties and the detection efficiency of the composite films were investigated.Results demonstrate that the detection efficiency roughly shows regular consistency with the magnetostrictive strain of the TbDyFe films. Heat treatment has a great effect on the crystalline state and the magnetostrictive strain of the composite materials. The as-deposited(Tb_(0.3) Dy_(0.7))Fe_(1.95) films are amorphous, and the saturation magnetostriction(ls) is only 90 ppm. However, the nanostructured crystalline REFe2 is partially separated out in amorphous matrix after annealing at 600C for 1 h, and the ls increases to 265 ppm. Simultaneously, the detection efficiency of the composite materials is obviously improved compared to that of the as-deposited films. The detection signal of traditional FeCo strip is0.4 V at the excitation power of 1.0 P and frequency of 128 kHz and that of the strip increases significantly by depositing one layer of(Tb_(0.3) Dy_(0.7))Fe_(1.95) film. The detection signal of the composite material annealed at 600C is the best, even reaching saturation value of 2.5 V(1.0 P, 128 kHz). The results may provide us with a method for preparing new materials for NDT.

Small-molecule based thermally activated delayed fluorescence materials with dual-emission characteristics

Organic thermally activated delayed fluorescence(TADF)emitters have attracted increasing concerns,owing to their atypical photophysical features that can pave the way to the innovative engineering applications.As cutting-edge type of luminescent molecules,however,most of them only exert a single-wavelength emission from the lowest excited state,according to Kasha’s rule.To develop their potential applications in multicolor luminescence and multi-functional luminescent probes for biological imaging,researchers have begun to turn their attention to design organic TADF molecules with dual-emission characteristics,by employing an additional fluorescence,phosphorescence,or TADF signal within a single-component system.We herein summarized the design principles as well as the luminescence mechanism of organic donor-acceptor TADF compounds with dual-emission characteristics,the superiority of which can cover unique material applications in modern luminescencerelated fields.

Synthesis and Bioactivities Evaluation of Novel Anthranilic Diamides Containing N-(tert-Butyl)benzohydrazide Moiety as Potent Ryanodine Receptor Activator

Anthranilic diamides have been proven to be a class of efficacious and safe insecticides targeting ryanodine receptors (RyRs) during the last decade. In order to develop innovative scaffolds with high insecticidal activity, two series of N-pyridylpyrazole derivatives containing N-(tert-butyl)benzohydrazide substructures were designed and synthesized. Their insecticidal activities against oriental armyworm (Mythimna separata) and diamondback moth (Plutella xylostella) were evaluated. Preliminary bioassay results revealed that some of the new compounds exhibited good insecticidal activity against the oriental armyworm and diamondback moth. The mode of action of these compounds were verified using calcium-imaging technique and the results showed that some new compounds could effectively modulate the insect cytosolic Ca^2+ level, and break the cellular calcium homeostasis, indicating some of these compounds were potent activators of the RyRs.

The unusual physicochemical properties of azulene and azulene-based compounds

Azulene,an isomer of naphthalene,has become one of hot chemical structures in the research field of functional materials,due to its anti-Kasha's rule emissions and unusual physicochemical properties(e.g.,photophysical,electrochemical,and photoelectrochemical properties).In the past,the synthesis of azulene-based compounds is relatively inconvenient.Recently,there have been more and more reports about the synthesis strategies of the azulene-based compounds for finely tuning the physicochemical properties.In this article,we introduce several synthetic methods for kinds of azulene-based compounds which has unusual physicochemical properties.With these convenient methods and unique physicochemical properties,azulene-based compounds can be applied into many fields such as specific bioimaging,advanced molecular switches,organic field-effect transistor(OFET),organic light emitting diode(OLED),solar cells,and so forth.And these properties are also summarized here.

Visualizing Material Processing via Photoexcitation-ControlledOrganic-Phase Aggregation-Induced Emission

Aggregation-induced emission(AIE)has been much employed for visualizing material aggregation and self-assembly.However,water is generally required for the preparation of the AIE aggregates,the operation of which limits numerous material processing behaviors.Employing hexathiobenzene-based small molecules,monopolymers,and block copolymers as different material prototypes,we herein achieve AIE in pure organic phases by applying a nonequilibrium strategy,photoexcitationcontrolled aggregation.This strategy enabled a dynamic change of molecular conformation rather than chemical structure upon irradiation,leading to a continuous aggregation-dependent luminescent enhancement(up to~200-fold increase of the luminescent quantum yield)in organic solvents.Accompanied by the materialization of the nonequilibrium strategy,photoconvertible self-assemblies with a steady-state characteristic can be achieved upon organic solvent processing.The visual monitoring with the luminescence change covered the whole solution-to-film transition,as well as the in situ photoprocessing of the solid-state materials.

Self-twisting for macrochirality from an achiral asterisk molecule with fluorescence-phosphorescence dual emission

Understanding of the role of supramolecular chirality for tuning material optoelectronic properties has been restricted by the limited number of cases. A particular challenge is to impose supramolecular chirality onto multicolor luminescent systems that can emit in aggregation state. Here we present a self- assembly strategy from a well-selected asterisk molecule for generating supramolecular chirality with fluorescence-phosphorescence dual emission. The work takes advantages of （1） achiral chemical structure dependent peculiar self-assembly that can spontaneously undergo symmetry breaking to produce macrochirality, and （2） the assembly process can be monitored by time which due to the crystallization-driven self-assembly by self-twisting, allowing a self-progressing chiral amplification. A multicolor luminescence induced by the fluorescence-phosphorescence dual emission along with such a self-assembly behavior was also observed at a single solution system versus the time. The self-twisting chiral self-assembly fashion provides new prospects for understanding the establishment of nanochirality from achiral molecular building blocks.

High-contrast flicker luminescence on dynamic covalent structure based nanoaggregates

In nanoscience, molecular switches have played a significant role to deliver different control abilities to practical functions,whereas high-contrast luminescence switchable manipulation at nanoscale is still limited. Since the tuning for emission behavior with high contrast ratio strongly connects to numerous visualized sensing and optoelectronic applications, we here report that autonomous p H control can be enrolled to address a high-contrast molecular emission change at the nanoaggregated level, for gaining a flicker luminescence performance in aqueous media. Employing a BODIPY contained dynamic covalent dye, we find its luminescent signal and nanoaggregate size can be spontaneously adjusted in water. On this basis, high-contrast luminescence switching of the material can be achieved upon the alternate introduction of base and acid into the aggregation state. Such a behavior can be attributed to a p H triggered photo-induced electron transfer regulation process. The dye aggregates can be well endocytosed for bioimaging and its luminescent variation can be autonomously displayed as a flicker effect. These results provide new visions for the design and development of smart materials with a dynamic luminescence behavior.

Microfluidic-directed magnetic controlling supraballs with multi-responsive anisotropic photonic crystal structures

The design and fabrication of anisotropic photonic crystal supraballs with multiple responses are highly desirable for versatile environmental sensing and flexible displaying.Herein,we developed an available strategy to construct a series of multi-responsive magnetic colloidal photonic crystal(CPC)supraballs with Janus and molecular-analogue structures.Initially,the humidity and temperature sensitive CPC supraballs were obtained via immobilization of polyacrylamide(PAM)and polyisopropylacrylamide(PNIPAM)hydrogels into the CPC structure,respectively,and CdTe/ZnS quantum dots endow the supraballs fluorescent signal under UV light.Furthermore,Fe_(3)O_(4) nanoparticles(NPs)were served as a magnetic hemisphere to construct CPC Janus supraballs which can be subsequently assembled into three different molecular-shaped cluster particles that integrate more response types via Fe_(3)O_(4) NPs hemisphere coalescence to a magnetic coupling center,recognizing multiple responses simultaneously that correspond the environmental altering.In addition,2D polychromatic patterns with sensitive CPC pixels printed by automatic printing system were demonstrated,which could monitor the changes of temperature and humidity.The multi-responsive magnetic controlling supraballs and 2D patterns reveal the promising applications in environmental sensing,anti-counterfeiting and displaying.

Topochemical polymerization of diphenyldiacetylene-based materials and the relevant application in photocatalysis

The diphenyldiacetylene （DPDA） and the corresponding polymers has become one of hot research topics in the field of functional materials, due to its highly π-conjugated system and outstanding electrochemical properties. Compared with routine polydiacetylenes, polydiphenyldiacetylene （PDPDA） has wider π-extension within the whole polymer structure and a larger internlolecular stacking tendency. Since the preorganization of monomers is essential for the topochemical polymerization, we here introduce several self-assembled methods and external-templated methods for the proper alignment of DPDA. From the perspective of morphology, the monomer structures and external templates are two of the important factors towards polymerization. Based on its structure, PDPDA can become a promising intelligent material for various optoelectical applications, and specifically we summarize the application of PDPDA as an effective phtocatalyst in organic pollutants degradation

Virtual special issue:Organic and polymer materials for electronics

Welcome to this virtual special issue focusing on organic and polymer materials for electronics published in Chinese Chemical Letters since 2017. For more than a century, people have always believed that organic compounds cannot be well employed for electronic conducting. Till 2000,Heeger,MacDiarmid and Shirakawa were acknowledged by the Nobel Prize of chemistry for