Sodium ion batteries (SIBs) have been regarded as a very suitable electrochemical energy storage technology for large-scale energy storage due to its low cost and high safety. Suitable anode material is one of the keys to boosting the commercialization process of SIBs. Significantly, hard carbon (HC) anode is considered as the most practical anode material for SIBs due to its rich natural sources, low cost, non-toxic, environmentally friendly, and low sodium storage voltage. However, hard carbon anode also faces the problems of low initial Columbic efficiency, insufficient long cycle stability and poor rate performance, which restrict its practical application in SIBs. In recent years, extensive investigations have been done to improve the performance of hard carbon anode, herein, this review discusses the recent progress of performance optimization strategies of hard carbon anode from four aspects, including structure control, morphology design, interface manufacture, and electrolyte optimization and conducts an analysis of the merits and demerits of each optimization method. Moreover, this review also discusses the bottlenecks and challenges in the process of practical application of hard carbon anode for sodium ion batteries.

Azulene is a nonalternant and nonbenzenoid hydrocarbon with bright blue color and a dipole moment of 1.08 D, and has received increasing attention due to its unique electronic structure and physicochemical properties. Herein, we report the design and synthesis of two types of azulene-based [4]helicene 1a/1b and 2 that contain isoelectronic B—N and C=C units at the electron-rich 1-position of azulene unit, respectively. Formation of the helical scaffolds is executed by the introduction of boron and alkyne to flexible biaryl precursors, where the Lewis acidic boron and alkyne were employed as “glue” to join two subunits into fully fused scaffolds via electrophilic boronation and platinum-catalyzed cycloisomerization of alkyne at the 1-position of azulene unit, respectively. All of azulene-based helicenes were investigated by ultraviolet visible (UV-vis) absorption spectra, cyclic voltammetry (CV) measurements and density functional theory (DFT) calculations. Additionally, 1a was further characterized by single crystal structure analysis. The results suggest that the introduction of B—N unit changed the electronic structure of the conjugated aromatic framework, leading to a narrow HOMO-LUMO gap. Moreover, the B—N unit also affects the aromaticity of the π-system as revealed by nucleus-independent chemical shift (NICS) via time-dependent density functional theory (TD-DFT) calculation. The single crystal structure analysis demonstrates that 1a has a helically twisted framework and Plus (P)/Minus (M) enantiomers. However, the Gibbs activation energy (ΔG^≠(T)) of the enantiomerization at room temperature is too low to separate two enantiomers by chiral high performance liquid chromatography (HPLC). Furthermore, the B—N unit exhibits partial double bond character and the BN-containing six-membered ring shows weak aromaticity. 1a with a phenyl group exhibits the deboronization upon addition of trifluoroacetic acid (TFA) as well as a specific sensing behavior to fluoride ion. However, 1b shows no deboronization upon addition of TFA and no sensing behavior to fluoride ion due to its steric hindered mesityl (Mes) group, but has a reversible stimuli-responsiveness with acid and base, this proton-responsiveness is similar to all-carbon analogue 2.

Photocatalytic reduction of CO₂ to valuable chemicals is an essential but still remains challenging. Metal-organic frameworks (MOFs) featuring high special surface area, large CO₂ adsorption uptakes, adjustable structures and function, have become a kind of promising porous materials for photocatalytic CO₂ reduction. However, MOFs often suffer from problems like short light harvesting range, rapid recombination of photogenerated carriers, resulting in lower activity. Here, graphene quantum dots (GQD) were supported on the Fe-based nano-sized MOFs, NH₂-MIL-88B(Fe), via electrostatic self-assembly strategy. GQDs were prepared by electrolysis of graphite rod in pure water firstly, and then centrifuged to remove the large species. Transmission electron microscope (TEM) reveals that ultrafine GQDs with 3 nm were obtained. Atomic force microscope (AFM) further demonstrates that the thickness of GQDs is around 0.34—1.5 nm (1—4 stacked layers). The MOFs, NH₂-MIL-88B(Fe), were synthesized with traditional solvothermal method, with a nano spindle shape of 250 nm×40 nm. The amino groups on MOFs provide strong electrostatic force with the carboxylic groups on GQDs, making the composite very stable and efficient electron transfer. High resolution transmission electron microscope (TEM) reveals that the nano MOFs were surrounded by tiny GQDs firmly. The bandgap of composite was determined by solid ultraviolet visible diffuse reflectance spectroscopy (UV-Vis DRS) and Mott-Schottky measurement, which indicate that it is thermodynamically appropriate for photocatalytic CO₂ reduction. Photocurrent experiments further demonstrate the composite is beneficial for the photogenerated electron-hole separation. Thus, the resulting GQD/NH₂-MIL-88B(Fe) composite showed much enhanced CO production rate (4 times) compared with the parent NH₂-MIL-88B(Fe), reaching 590 μmol/g under 10 h visible light irradiation with triethanolamine (TEOA) as sacrificial agent. The hugely improved photoreduction activity benefits from both the high CO₂ adsorption of MOFs and the enhanced separation of photogenerated electrons and holes. This work provides an avenue for preparation of MOFs based materials with high CO₂ photoreduction activity.

Photoredox catalysis is a practical and efficient synthetic technique that enables previously challenging or even impossible chemical transformations proceeding effectively. As one of the most prominent contribution to green chemistry, it provides a sustainable platform to the generation of high reactive radical species under mild reaction conditions. On the other hand, β-fluoro α-amino acids are significant structural units present in enzyme inhibitors, drugs and probes. Catalytic β-C(sp³)―H fluorination of α-amino acid represents a direct synthetic approach, but the harsh reaction conditions and the limited substrate scopes lead to high difficulty for these methodologies to being generalized to industrial application. Here, we report a novel and modular protocol that is via photoredox catalytic radical coupling. By using a dicyanopyrazine-derived chromophore (DPZ) as the photoredox catalyst, two readily accessible starting substrates, that are N-aryl glycine esters and α-fluoro-aryl acetic acid-derived redox-active esters (RAEs), can undergo single-electron oxidation and reduction, respectively. The resulting ester-substituted α-amino radicals and α-fluoro benzylic radicals then experience cross coupling, a highly reactive process in radical chemistry. As a result, a series of β-fluoro-α-amino acid derivatives were obtained in high yields. In this transition metal-free catalytic system, no extra oxidant or reductant is required, representing a redox neutral platform. General procedure for the synthesis of β-fluoro-α-amino acid derivatives is: to a flame dried Schlenk tube was sequentially added N-aryl substituted glycine esters 1 (0.4 mmol), RAEs 2 (0.2 mmol), DPZ (0.004 mmol, 1.42 mg), tetra-n-butyl- ammonium bromide (0.04 mmol, 12.9 mg), sodium dihydrogen phosphate (0.40 mmol, 48 mg) and cyclopentyl methyl ester (CPME) (4 mL). Then degassed three times by freeze-pump-thaw method. The reaction mixture was stirred under an argon atmosphere at 25 ℃ irradiated by a 3 W blue LED for 48 h. After completion of the reaction, the reaction mixture was directly loaded onto a short basified silica gel column, followed by gradient elution with petroleum ether/ethyl acetate (V/V, 8/1). Removing the solvent in vacuo, afforded products.

Coupling or condensation reagents that could be used to promote the condensation of carboxylic acids with amines to furnish amide bonds play crucial roles in solid phase peptide synthesis (SPPS) of peptides and peptide-based derivatives. Compared with traditional coupling reagents used in SPPS such as 1-hydroxy-7-azabenzotriazole (HOAt) and 1-hydroxybenzotriazole (HOBt), the novel N,N'-diisopropylcarbodiimide (DIC)/ethyl 2-cyano-2-(hydroxyimino) acetate (Oxyma) condensation system has advantages of inexpensiveness, safety, high coupling efficiency, low racemic rate, and compatibility with manual and automatic peptide synthesis represented by microwave-assisted SPPS. However, the effects of different reaction temperatures (e.g. 28, 50, and 75 ℃) on the coupling efficiency of DIC/Oxyma and on the easily oxidized amino acids such as methionine (Met) remain to be further investigated. The transient receptor potential ankyrin 1 (TRPA1) channel plays an important role in temperature perception, auditory perception, and inflammatory pain. As a novel non-covalently TRPA1-specific agonist, Wasabi Receptor Toxin (WaTx) that consists of 33 amino acid residues and two pairs of disulfide bonds is considered as an important molecular tool to study the opening mechanism and function of TRPA1. In this study, 2-(6-chloro-1H-benzotriazole-1-yl)-1,1,3,3-tetramethylaminiumhexa-fluorophosphate (HCTU)/N,N'-diisopropyl- ethylamine (DIEA) and DIC/Oxyma condensation systems were separately utilized to explore the synthetic efficiency of linear WaTx and the oxidative degree of Met residues at different temperatures. The robustness of DIC/Oxyma condensation system was validated by the rapid manual synthesis of linear WaTx. The one-step and two-step oxidative folding strategies were separately applied for the construction of two pairs of disulfide bridges, affording the active WaTx, which was further confirmed by circular dichroism and calcium fluorescence assay. In this study, a moderate, efficient synthesis and renaturation folding method of WaTx was established. Moreover, the effects of different reaction temperatures on the synthetic efficiency of DIC/Oxyma and on amino acid residues oxidization were compared for the first time. From the aspects of reaction efficiency (represented by the timescale of the overall Fmoc deprotection-washing-amino acid coupling SPPS cycle), amino acid residues oxidization and synthetic cost, n(Fmoc-amino acid):n(DIC):n(Oxyma)=3:6:3 under 50 ℃ should be the ideal reaction condition. This work provides both an imperative complement for SPPS and a particularly useful strategy for the manual efficient synthesis of disulfide-containing peptides with easily oxidized groups.

Allylic chiral centers are widely present in natural products and pharmaceutically active molecules, and play a vital role in the construction of organic compounds through pericyclic reactions, oxidations or reductions and other transformations. The transition metal-catalyzed asymmetric addition or coupling reaction using alkenyl metal nucleophiles is one of the most attractive strategies for the synthesis of these structures. Among the many metal catalysts, earth-abundant transition metals such as iron, cobalt, nickel and copper have been used to replace precious metals such as rhodium and palladium, and have gained attention for use in enantioselective alkenylations. Indeed, remarkable advances have been achieved with these catalysts due to their unique catalytic activity, low toxicity and environmentally friendliness. The earth-abundant transition metals are known to undergo facile one electron oxidation state changes. In the reaction process, the earth-abundant transition metals have the ability to undergo two-electron transfer and single-electron transfer processes, therefore they have more valence changes and catalytic pathways which can be exploited. Based on this, this article will review the latest research in earth-abundant metal-catalyzed enantioselective alkenylation using alkenyl metal reagents. It is divided into four sections consisting of cobalt-catalyzed enantioselective alkenylations using alkenyl metal reagents, nickel-catalyzed enantioselective alkenylations using alkenyl metal reagents, copper-catalyzed enantioselective alkenylations using alkenyl metal reagents, and other earth-abundant transition metals catalyzed enantioselective alkenylations using alkenyl metal reagents.

The worldwide outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has resulted in the infection even death of people all over the world, which has gravely affected our daily life. Globalization of trade and convenient transportation immensely accelerate the propagation of the epidemic, which brings severe difficulties to prevent the epidemic. Therefore, rapid and accurate diagnosis of infected persons and screening of asymptomatic persons play an important role. At present, the most widely used method for the detection of SARS-CoV-2 is reverse transcription-polymerase chain reaction (RT-PCR), which still has some problems including complicated sample storage and transportation, complex operations and so on. These shortcomings cause the hindrances to achieve fast, simple, efficient diagnostic testing under the normalization of the epidemic. In the past few years, with the development of nanotechnology, bio-sensing methods based on nano photonics have become a research hotspot. Label-free optical methods have been widely explored for bio-sensing including virus detection, such as surface plasmon resonance (SPR), surface enhanced Raman scattering (SERS), whispering gallery mode (WGM) and colorimetry. These approaches offer available alternatives to improve the speed, sensitivity, and accuracy of optical bio-sensing, owing to the enhanced interaction between the nanostructure and the biomarkers. This review summarizes these nano photonics-based bio-sensing technologies for the detection of SARS-CoV-2. Moreover, the detection mechanism of biomarkers by nano photonics is explained, and the further development trends are discussed. In view of the difficulties in manufacturing nano photonics structures, a new strategy of large-area preparation of nano photonics structures using nano green printing technology is proposed, which provides theoretical and technical support for accurate and effective prevention and control of the epidemic diseases.

²¹¹At, with a half-life of 7.2 h, is an excellent radionuclide being investigated for use in targeted alpha therapy as the result of very high linear energy transfer. However, the production of ²¹¹At is limited by ²¹⁰At, because ²¹⁰At decays to produce long half-life (138.4 d) extremely toxic daughter ²¹⁰Po. The production of ²¹¹At via ²⁰⁹Bi(α,2n) nuclear reaction and ²¹⁰At via ²⁰⁹Bi(α,3n) nuclear reaction, as the energy of incident α-particle increases, the ratio of N(²¹⁰At)/N(²¹¹At) increases. In this research, the α-particle is provided by the Chinese Accelerator Driven Sub-critical System (ADS) Front-end Demo Linac at Institute of Modern Physics, Chinese Academy of Sciences. The technical process of ²¹¹At produced was studied systematically, including accelerator irradiation, separation by dry distillation method, quality analysis, and monoclonal antibody labeling. The bismuth targets were irradiated with α-particle by 28.18, 28.34, 28.48 28.92 MeV, and the target chamber adopts an inclined target with water cooling to improve the cooling effect. The dry distillation separation was carried out at a high temperature of 850 ℃, oxygen as the carrier gas, chloroform and ethanol as eluent, and the chloroform solution containing ²¹¹At was blow dry with nitrogen. The results showed that the total recovery of dry distillation separation of ²¹¹At reached 78.53%. After separation, the quality analysis of ²¹¹At was performed using a high-purity Ge-detector, alpha energy spectrometer, and mass spectrometer. The obtained solid ²¹¹At had high specific activity, radionuclide purity and chemical purity, where the content of impurity elements Bi, Cu, Zn, and Al was less than 100 ng/GBq, and the ratio of N(²¹⁰At)/N(²¹¹At) was less than 10^–5 when the incident particle energy is below 28.2 MeV. Finally, the labeling of ²¹¹At-nimotuzumab was realized through N-succinimidyl-3-(trimethylstannyl)benzoate, and the labeling rate was 94.86%. Based on this research, a set of simple and efficient separation methods was established, which laid a good foundation for the subsequent production and application of ²¹¹At in China.

With the advance of industrialization of human society, fossil energy has been overconsumed, and excessive carbon dioxide has been discharged into the atmosphere, resulting in energy crisis and environmental issues. The preparation of high value-added fine chemicals by electrocatalytic reduction of carbon dioxide is one of the directions to explore the establishment of artificial carbon cycle, which has attracted extensive attention in fundamental research and industrial applications. Structural design and preparation of electrocatalysts with high activity, selectivity and stability are of great significance to achieve efficient catalytic performance for carbon dioxide reduction. In recent years, many studies have reported the structural design ideas and application cases of catalyst and electrode materials, and remarkable progress has been made. In this review, the regulation strategies of catalyst structure and electrode structure are summarized from four aspects: size effect, surface characteristics, defect engineering and multi-stage structure, and the development of electrocatalytic carbon dioxide reduction is prospected.

The synthesis of stable single-metal site catalysts with high catalytic activity and selectivity with a controllable coordination environment is still challenging. Due to the different electronegativity of different coordination atoms (N, P, S, etc.), adjusting the coordination atom type of the active metal center is an effective and wise strategy to break the symmetry of the electron density. We adopted a cation exchange strategy to synthesize two Cu single-atom catalytic materials with different coordination structures. This strategy can change the coordination environment of Cu single atom by changing the different organics wrapped around Cu-CdS. This strategy mainly relies on the anion skeleton of sulfide and the N-rich polymer shell to produce a large number of S and N defects during the high-temperature annealing process, and the precise synthesis of a single-metal Cu site catalyst material with rich edge S and N double modification. In these two materials, one single Cu atom has double coordination of sulfur (S) and nitrogen (N), and the other single Cu atom has only a single S coordination. The first shell coordination number of Cu central atom is 4, the structure of Cu-S/N-C is Cu-S₁N₃, and the structure of Cu-S-C is Cu-S₄. The results show that the catalytic performance of Cu-S/N-C in the hydrogenation of nitrobenzene compounds is much better than that of Cu-S-C, that is, the Cu monoatomic materials with S and N double-modified metal sites has better hydrogenation activity than single S-modified metal sites. After 20 min of reaction, under the catalysis of Cu-S/N-C, the conversion rate of nitrobenzene reached 100%, and the activity did not decrease significantly after being recycled for 5 times. It shows that the Cu-S/N-C catalytic material with a single-atom structure we synthesized has good stability. This discovery not only provides a feasible method for adjusting the coordination environment of the central metal to improve the performance of single-atom catalytic materials, but also provides an understanding of the catalytic performance of heteroatom modification.

Radiotherapy is a traditional treatment method that utilizes high-energy radiation to inhibit cancer cells and has been widely used in the treatment of malignant tumors. However, high-energy radiation can not only cause damage to tumors, but also cause side effects to normal tissues. Although some small-molecule radioprotection agents have been used in clinics, their short blood circulation time and faster metabolism greatly reduce the protective effects. In the last twenty years, with the rapid development of nanotechnology in biomedicine, radioprotection nano-agents have provided new candidates for improving the protective effect. Rational design of radioprotection nano-agents is demanded to solve the drawbacks of existing small-molecule radioprotection agents. In view of the many advantages of nanomaterials for radioprotection, this review summarized the common design strategies of nanometer radioprotection materials, and analyzed the pathogenic mechanism of common radiation-induced diseases as well as the treatment of various radiation-induced diseases by radioprotection nano-agents. In addition, this review also discussed the challenges and future prospects of nanomaterial-mediated radioprotection during radiotherapy.

In view of the importance of sulfonyl groups in organic molecules, the introduction of sulfonyl groups and the synthesis of sulfonyl compounds have been widely reported. Among them, the synthesis of sulfonylhydrazides has attracted much attention because of their biological activities in antitumor and antibacterial activities. Here, we developed a photoinduced reaction of potassium alkyltrifluoroborates, DABCO•(SO₂)₂ (1,4-Diazabicyclo[2.2.2]octane, DABCO), and aroylhydrazides under visible light irradiation, which obtained N'-acyl-N-alkylsulfonylhydrazides in moderate to good yields in one-pot. This reaction works in a green and mild way with a broad substrate scope. Mechanistic study shows that after giving rise to N-acyldiazenes via the oxidation of aroylhydrazides, the transformation is initiated by alkyl radicals generated in situ from potassium alkyltrifluoroborates in the presence of photocatalyst. The subsequent insertion of sulfur dioxide and alkylsulfonylation of N-acyldiazenes with alkylsulfonyl radical intermediates afford the corresponding N'-acyl-N-alkylsulfonyl- hydrazides. General procedure for visible-light photocatalytic alkylsulfonylation of aroylhydrazides with alkylsulfonyl radicals: to a solution of aroylhydrazides 1 (0.2 mmol) and K₂CO₃ (0.3 mmol) in MeCN (2.0 mL) was added I₂ (0.12 mmol). The reaction was stirred for 3 h at room temperature, then quenched with sat. aq. Na₂S₂O₃ (15 mL). The layers were separated and the aqueous layer extracted with dichloromethane (DCM) (15 mL×3). The combined organic layers were then washed with brine (15 mL), and dried over Na₂SO₄. Evaporation of the solvent under reduced pressure afforded the crude N-acyldiazenes, which was used in the subsequent transformation without further purification. The crude N-acyldiazenes were combined with potassium alkyltrifluoroborates 2 (0.24 mmol), DABCO•(SO₂)₂ (0.2 mmol) and 9-mesityl-10-methylacridinium perchlorate ([Mes-Acr]ClO₄) (0.004 mmol) in a tube. The tube was evacuated and backfilled with N₂ three times before the addition of MeCN (2.0 mL). The mixture was then placed around blue light emitting diodes (LEDs) (30 W) with a distance of 10 cm, and was stirred under blue light irradiation for overnight at room temperature. After completion of reaction as indicated by thin layer chromatography (TLC), the solvent was evaporated and the residue was purified directly by flash column chromatography (V(n-hexane)/V(ethyl acetate)=5∶1—2∶1) to give the N'-acyl-N-sulfonylhydrazides 3.

Amines have a wide variety and are readily available. Due to the larger C—N bond energy of amines, C—N bond of amines generally needs to be activated before cleavage. In recent years, a variety of activation methods of amino groups have been developed. Among the activation methods, converting amines into quaternary ammonium salts has certain advantages of easy preparation and stable storage. In last decade, quaternary ammonium salts derived from aromatic amines and benzylamines have made great progress in the study of constructing various C—X bonds via cleavage of C—N bond. This review mainly discusses the formation of C—X bonds of quaternary ammonium salts via cleavage of C—N bond with or without transition metal catalysts over the past few years. Via C—N bond breakage, quaternary ammonium salts can construct C—B bond, C—C bond, C—N bond, C—O bond, C—Si bond, C—P bond, C—S bond, C—Se bond, and so on. And thus borates, aromatics, alkanes, ethers, amines, silanes, phosphines, thioethers, disulfides, selenoethers, diselenides and other compounds are synthesized. Moreover, if the quaternary ammonium salts derived from chiral benzylamines are adopted, a variety of highly enantiopure chiral organic compounds are obtained. The chiralities of quaternary ammonium salts are excellently kept in the products, and S_N2 type configuration reversal occurs for all of the reported reactions.

During the past 170 years, organic small molecular fluorescent dyes had been widely applied in fluorescence labeling, fluorescence probes and bioimaging. And their structures and performances continually evolved with development of synthetic method and application. However, the emerging super-resolution imaging put forward higher requirements at brightness, stability and switching performance of organic small molecular fluorescent dyes, which also offers new opportunity for developing novel dyes at the same time. So, chemists presently pay more attentions on brightness and photostability. Twisted intramolecular charge transfer (TICT), the major nonradiative decay channel in organic small molecular fluorescent dyes, seriously decrease brightness and photostability. Therefore, inhibiting TICT has became the crucial strategy to develop organic small molecular fluorescent dyes towards super-resolution imaging. This review will firstly demonstrate mechanism and development of TICT and emphatically introduce the progress in improving organic small molecular fluorescent dyes based on inhibiting TICT.

Bacterial infection and resistance have threatened public health and it is necessary to develop a novel and efficient antibacterial agent. Metal-organic frameworks (MOFs) have been widely studied and applied in the antibacterial field. The porous carbon frameworks could provide intrinsic conditions to avoid the agglomeration and avail the stabilization of metal nanoparticles, which may be some synergies. Herein, a novel kind of AgNPs@ZIF-67 composite nanoparticles was prepared by a green, rapid, and cost-effective method, during which zeolitic imidazolate framework-67 (ZIF-67) acted as a template and small silver nanoparticles (AgNPs) could be facilely prepared in situ by the reduction of silver ions with fresh sodium borohydride (NaBH₄). Specifically, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images confirmed the existence of as-prepared AgNPs with average diameters of (7.05±0.09) nm and the introduction of AgNPs did not alter the size and rhombic dodecahedron-type morphology of ZIF-67. Energy-dispersive X-ray spectroscopy (EDS) elemental mapping revealed that AgNPs@ZIF-67 mainly contained uniformly dispersed C, N, O, Co and Ag elements. And the loading ratio of Ag weight content was 0.98% in it. The X-ray diffraction (XRD) pattern of the AgNPs@ZIF-67 sample showed a series of typical and sharp diffraction peaks in the (011), (002), (112), and (222) planes but no obvious peaks attributed to the AgNPs, which exhibited the formation of phase-pure ZIF-67 and well-dispersed of metallic Ag in ZIF-67. Zeta potentials showed a higher potential of ZIF-67 (+25.6 mV) than AgNPs@ZIF-67 (+17.7 mV), indicating the load of negative charged AgNPs and good stability of the as-obtained AgNPs@ZIF-67. Furthermore, Staphylococcus aureus (S. aureus) (ATCC 6538) was used in the antibacterial assay and the bacterial concentration was regarded as 1×10⁸ CFU• mL^–1 when the OD₆₀₀ value of the suspensions was 0.1. The in vitro minimum inhibitory concentration (MIC) of AgNPs@ZIF-67, ZIF-67 were 300, 350 µg•mL^–1, respectively. The antibacterial efficiency of AgNPs@ZIF-67, ZIF-67, and AgNPs at 24 h were 99.889%, 57.192%, and 26.433%, respectively. It was illustrated that the decoration of AgNPs could significantly improve the antibacterial ability of ZIF-67 nanomaterials. Moreover, SEM images of S. aureus showed that AgNPs@ZIF-67 did more serious damage to the cell membrane than ZIF-67. This work provided a facile method to fabricate the AgNPs@ZIF-67 composite nanoparticles, which was demonstrated as a promising antibacterial material based on the synergistic effect of AgNPs and ZIF-67.

Electrochemical production of H₂O₂ from O₂ via the two-electron reduction reaction (2e-ORR) is a green and safe process that is being heavily investigated. Zeolitic imidazolate frameworks (ZIF) as a subclass of metal-organic frameworks (MOFs) have attracted enormous scientific interests due to their high porosity, excellent mechanical stability, tunable surface properties, and exceptional chemical and thermal stabilities. Herein, a series of pyrolyzed ZIF catalysts (p-ZIF) were synthesized by treating 2-methylimidazole zinc salt (ZIF-8) at high temperatures (900, 950 and 1000 ℃). During pyrolysis, zinc was vaporized, leaving the metal-free nitrogen-doped porous graphitic carbon materials. The effects of the pyrolysis temperature on the structure and catalytic performance of the p-ZIF catalysts in 2e-ORR were systematically studied. In 2e-ORR in an acidic electrolyte, the p-ZIF catalysts displayed low overpotential, low Tafel slope, and negligible activity loss after 3000 cycles of accelerated durability testing (ADT). In particular, the p-ZIF-950 catalyst possessed the highest H₂O₂ partial current of 0.185 mA at 0 V vs. RHE, followed by the p-ZIF-900 (0.146 mA) and p-ZIF-1000 (0.135 mA) catalysts. The H₂O₂ selectivity over the p-ZIF-950 catalyst was also constantly higher than those over the other two p-ZIF catalysts across the potential range investigated and maximized at 89.2%. Highly efficient and durable H₂O₂ production was demonstrated on the p-ZIF-950 catalyst by the linear accumulation of H₂O₂ to 522 mmol•g_cat^-1 within 6 h, translating to an H₂O₂ production rate of 87 mmol•g_cat^-1•h^-1. The morphology, composition, carbon defect, texture, and surface chemical state were characterized by techniques such as transmission electron microscopy (TEM), elemental analysis, Raman spectroscopy, N₂ physisorption, and X-ray photoelectron spectroscopy (XPS). The p-ZIF catalysts not only nicely carried over the regular rhombic dodecahedral morphology of ZIF-8, but also possessed abundant amount of nitrogen, high specific surface area, and hierarchical pore structure. According to the characterization results, the specific surface area and carbon defect are unlikely the key factors that determine the catalytic performance, while the evolutions of the average pore size and surface content of graphitic N mimicked those of the H₂O₂ partial current and selectivity on the p-ZIF catalysts. In light of the literature works, the large pore size is proposed to facilitate the in-diffusion of O₂ and out-diffusion of H₂O₂, while the graphitic N is able to enhance the activation of O₂ and desorption of H₂O₂, both of which are beneficial to the kinetics of the 2e-ORR reaction.

Nowadays, under the background of energy shortage and “double carbon”, clean and efficient utilization of energy is very important. Zeolite catalyst is an important means to improve the output and quality in the process of energy processing, and has become a research hotspot in this field. From natural zeolites to artificial zeolites, from three-dimensional (3D) zeolites to two-dimensional (2D) zeolites, with the further study of zeolites, their properties and structures are gradually clear, and they are widely used in catalysis, adsorption, separation and other industries. Especially the 2D zeolites with unique crystal structure (or morphology), their lamellar structures not only reduce the molecular transmission path, but also provide more active sites for the catalytic reaction system and reduce the carbon deposition rate, which have great application potential in the future. When it comes to 2D zeolites, structure directing agent plays a very important role, the types of 2D zeolites can be broadened by changing the structure of directing agent structure, and in this way, the structural change elasticity of zeolites can be increased, which meets the industrial requirements and has a wide range of adaptability. Here, this paper summarizes the development process of 3D and 2D molecular sieves, focuses on the catalytic efficiency of zeolites, expounds their structure-activity relationship in different fields such as coal tar catalytic conversion, C1 chemical industry and biomass catalytic conversion, as well as the preparation path of 2D zeolites, summarizes the conversion mechanism, and analyzes the advantages of 2D zeolites in specific surface area and active site accessibility, it provides a reference for the application of 2D zeolite molecular sieves in industry.

Ring-opening metathesis polymerization (ROMP) is a strategy in which monocyclic or polycyclic olefins undergo ring-opening polymerization to form functionalized polymers. ROMP has been recognized as a powerful synthetic strategy for the synthesis of advanced polymeric materials. Recently, star polymers are receiving intense interests in materials science and nanotechnology in both academic and industrial fields due to the unique structure and property. In this review, the applications of ROMP in the synthesis of star polymers are discussed in terms of methods of polymerization, monomers, initiators and crosslinking agents. Moreover, the application fields and prospects of the ROMP synthesized star polymers, and the advantages and limitations of various ROMP methods are also presented. This work aims to promote development of ROMP in the synthesis of star-shaped polymers, provide a new scientific research approach for the synthesis of functionally complicated star-shaped polymers, and contribute to the acceleration of the commercialization of star-shaped polymer materials.

Diarylmethine structure units are widely present in natural products and pharmaceuticals with important physiological and pharmacological activities. The enantioselective control of its stereogenic center, which is the most unique in this structure unit, has often become a difficulty and challenge during the research of total synthesis of natural products. Therefore, this field has attracted great interest to many organometallic chemists and synthetic organic chemists. In recent years, the construction methods of this stereocenter developed rapidly, and new reactions and reagents have emerged one after another. Some highly efficient catalysts have been invented, exhibiting unique catalytic activity and selectivity. In this review, according to the difference of reaction types, these methods can be divided into six types, such as asymmetric conjugate addition reaction (asymmetric 1,4-addition reactions involving aryl boronic acids, asymmetric 1,4-addition reactions involving aryl borates, enantioselective organocatalytic 1,4-addition reactions, asymmetric 1,4-conjugate addition induced by Evans chiral imide and asymmetric 1,6-conjugate addition of para-quinone methides), asymmetric allylation or propargylation of aromatic rings, transition metal-catalyzed asymmetric cross-coupling reaction, transition metal-catalyzed asymmetric C―H bond activation and functionalization, three-component reactions for asymmetric synthesis of 1,1-diaryl alkanes, asymmetric hydrogenation reactions for 1,1-diaryl alkanes, etc. This review aims to collect and summarize the asymmetric construction methods of diarylmethine stereogenic centers, and their applications in the total synthesis of natural products in the past decade. Finally, from the perspective of total synthesis, we further summarize and analyze the future development trend for the construction of diarylmethine chiral stereogenic centers, and encourage young generation to develop new methods and reagents that can avoid use of precious metals/catalysts and therefore are more efficient and environmentally friendly. More importantly, we hope that the developments of these practical methodologies can be further applied to asymmetric total synthesis of natural products and medicines, and eventually solve the source problem of these “useful molecules” with potential medicinal value.

Neptunium (Np) and plutonium (Pu) are two important actinides in nuclear industry. They can be generated through neutron capture of uranium (U) in reactors or decay from other transuranic elements. Representative isotopes of Np and Pu such as ²³⁷Np and ²³⁹Pu have long half-lives and possess high radiotoxicity, therefore may impose great hazard to biological system if they are released into the environment. The rich redox chemistry of Np and Pu further adds complexity of their chemical behavior in the environment. The coordination chemistry of Np and Pu in aqueous solution is of great significance to help understand and control their speciation distribution and migration behaviors in aqua environment. This article reviews the advances in coordination chemistry of Np and Pu with several common inorganic anions (OH^–, $CO_3^{2-}$, $SO_4^{2-}$, Cl^–, $NO_3^-$, F^–, $PO_4^{3-}$) in aqueous solution, especially the speciation and coordination thermodynamics between Np/Pu in different oxidation states and these anions. In general, Np and Pu ions in the same oxidation state exhibit similar coordination behavior (species, structure, stability constants, etc.) when coordinating with the same anion. The coordination strength for Np/Pu ions in different oxidation states with the same anion ligand is roughly in the order of IV>III, VI>V. For the coordination of Np/Pu ions with different anions, the strength sequences are OH^–>F^–> ${H_2}PO_4^-$> $NO_3^-$>Cl^– for monovalent anions and $CO_3^{2-}$> $HPO_4^{2-}$> $SO_4^{2-}$ for divalent anions. Factors such as instability of Np/Pu ions in some oxidation states, weak complexation, and low solubility of the complexes in the aqueous solution cause difficulties in obtaining precise and reliable coordination parameters for these ions experimentally. Moreover, the coordination parameters determined by different methods may vary with each other. To obtain more reliable parameters for the coordination of Np/Pu ions with these anions in the future, the use of more advanced characterization methods and the assistance of theoretical computation may provide strong support.

Photonic synapse transistors have attracted growing attention due to their salient advantages in information transmission/processing and good potentials for analog neural computing. Currently, most synapse transistors are rigid devices with the limitations in flexible and highly photosensitive semiconductor channel layers. To achieve high-performance flexible photonic synapse transistors, it is essential to develop stimuli-responsive organic semiconductor thin-films to broaden the photo-response range of devices and accelerate separation of photoinduced carriers for improving synaptic performances. Here, poly(3-hexylthiophene) (P3HT) and poly(indacenodithiophene-co-benzothiadiazole) (PIDT-BT) materials with complementary optical absorption have been used to fabricate a bulk composite film of organic semiconductor heterostructures by a solution-processing method. The surface structures and optoelectronic properties of the PIDT-BT:P3HT film and their single component films are studied. By using the PIDT-BT:P3HT heterostructure film as a novel photoactive channel layer, flexible low-voltage photonic synapse transistors have been designed and fabricated with the combination of polyelectrolyte-based dielectrics. The effects of different optical stimulation conditions on the performance of synapse transistors are investigated with insightful discussion on the semiconductor mechanisms. The flexible synapse transistors based on the PIDT-BT:P3HT film exhibit higher excitatory postsynaptic currents than devices with the single component semiconductor layers at the same optical stimulation. The synaptic response of the PIDT-BT:P3HT-based device is also evaluated under different stimulus variables including the optical spike wavelength, duration and frequency. As results, good synaptic characteristics are observed including the high excitatory postsynaptic current, paired-pulse facilitation, and frequency-dependent properties with the tunable synaptic plasticity. It is found that the response in excitatory postsynaptic current of the synaptic device stimulated by two beams (520 nm green laser and 685 nm red laser) together is greater than the sum of the responses stimulated by each beam alone. These results are useful for the design of high-performance photoresponsive semiconductor films and photonic synapse transistors, which are conducive to the development of low-power flexible optoelectronic devices, artificial synapses and beyond.

In the past decades, the polyolefin industry has been booming, and the synthesis of polyolefin with unique structure and property has been the constant pursuit of polymer chemists. Until now, scientists have been able to synthesize various polyolefins by regulating monomer structure, catalyst central metal, ligand structure and polymerization conditions. Among the various polyolefins, those with aliphatic rings in the main chain have been widely concerned because of their excellent thermal stability and transparency. The coordination polymerization of α,ω-diolefin is a very efficient approach to obtain polymers containing aliphatic rings in backbone. This method has some advantages, such as easy availability and modification of monomers, and the effective regulation of polymer microstructure by catalysts. Polymers with pendant double bonds or aliphatic rings or crosslinked gel can be obtained according to the different double bond that inserts into the intermediate generating after the first insertion reaction. According to the relative orientation of two branched chains in the ring, the polymers are divided into cis and trans isomers. By the relative configuration of the rings, there are isotactic and syndiotactic structures. Due to the 1,2-insertion or 2,1-insertion of the first insertion reaction between the catalyst and the monomer, the resultant polymers contain ring units with monomethylene or dimethylene. Under the catalyzation of complexes with different absolute configurations, chiral polymers with the same optical rotation and opposite direction can be obtained. The microstructure of these polymers should have a significant influence on their aggregation state, thermodynamics and mechanical properties, which can be finely regulated by changing the central metal and ligand structure of the catalyst. This review focuses on the microstructure of polymers of α,ω-diolefins, and emphatically introduces how to regulate the polymer structure by varying the catalyst structure. Besides, the possible development direction of this field is predicted, so as to promote the rapid development of structure-performance relationship and practical application of these polymers.

Chiral amines are valuable constituents of many natural products, pharmaceuticals and functional materials, they are also widely utilized as versatile building blocks and important chiral catalysts as well as chiral auxiliaries in organic synthesis. Therefore, it is of great scientific significance and application value to develop efficient methods for the synthesis of structurally diverse chiral amines and chiral amine scaffolds. In 1993, Petasis and co-workers reported an efficient synthesis of allylic amines through a Mannich-type reaction of vinylboronic acids with secondary amines and paraformaldehyde, where the organoboron reagents served as the nucleophilic component. Since then, this three-component Petasis reaction of organoboron reagents with amines and carbonyl derivatives has been developed as an appealing and concise method to access various amines. The asymmetric Petasis reaction provides a facile and efficient route to optically active amines and thus has attracted much attention over the past two decades. In this review, we summarize the recent progress achieved in the synthesis of chiral amines by asymmetric Petasis reaction and provide an overview on the methods applied for stereochemical control. The strategies that have been employed for accessing enantioenriched amines, including various chiral substrate-based diastereoselective induction approaches and several recent developments of enantioselective catalysis. In a large number of asymmetric Petasis reaction cases, good to high levels of stereoselectivities can be achieved relying on the utilization of chiral amine source, chiral carbonyl substrates, and chiral organoboron reagents. In particular, chiral amines such as α-methylbenzylamines and chiral α-hydroxy aldehyde analogues have emerged as a broadly applicable class of substrates for asymmetric Petasis reaction. The most promising advance has been the success of catalytic asymmetric Petasis reaction for enantioselective synthesis of chiral amines in the last few years. Chiral bifunctional thioureas and binaphthols have been demonstrated to be effective organocatalysts. Finally, the perspectives on the relevant challenges and future directions in this field are also discussed.

Discotic liquid crystal consisting of polycyclic aromatic hydrocarbon (PAH) core and peripheral alkyl chains is a kind of soft organic materials showing semiconductivity and fluorescence, and it can be fabricated into opto-electronic devices by solution process or printing technique, with low-cost advantage. We report benzo[g]chrysene unsymmetrical functional discotic liquid crystals, which were synthesized by Suzuki-Miyaura cross-coupling reaction and Scholl oxidative annulation. Five new π-extended compounds containing ester, anhydride, imide and benzoimidazole unit were synthesized and characterized. Their liquid crystalline property was fully characterized by differential scanning calorimetry (DSC), polarized optical microscopy (POM) and small-angle X-ray scattering (SAXS), these compounds showed ordered columnar hexagonal (Col_hex) mesophase with broad mesophase range as wide as 206 ℃. The functional groups have essential impact on the phase transition temperatures. The ultraviolet-visible (UV-Vis) absorption and photoluminescent property were studied, they displayed fluorescent quantum yield as high as 34% in solution, and the emission spectra can be tuned from blue, green to red by functional group and π-conjugation extension. Density functional theory (DFT) computation results explained these physical properties. We anticipate that more π-extended functional molecules can be developed from naphthalic anhydride by our method.

The development of high-efficiency, green and energy-saving material separation and purification technology is of great significance, and gas separation has a wide range of applications in the fields of industry, energy, medical treatment and technology. Since traditional polymer membranes still face many challenges in achieving high-efficient gas separation, the development of new separation membrane materials has become the current hotspot and difficult issue. As an emerging porous coordination polymer, metal-organic frameworks (MOFs) materials have attracted great attention due to their unique, designable topological structures and tunable functionalities. In order to overcome the problem that bulk or powder MOFs are difficult to be used for gas separation efficiently, it is of great significance and a challenging task to develop MOFs membranes for separation. As a representative MOF material, MOF HKUST-1 is widely used to prepare membranes for gas separation due to its advantages of high stability, economic raw material and hierarchical pore structure. The preparation methods and gas separation performances of the HKUST-1 membrane in the past ten years are summarized, and some viewpoints and the research prospect on this research area are described.

Solution small-angle scattering (SAS) is a powerful tool for elucidating the structural properties of soft matter systems. SAS includes X-ray scattering (SAXS) and Neutron scattering (SANS) techniques which allow determination of the material’s properties at a scale ranging from few Angstroms to hundreds of nanometers. Wide time scales ranging from real time (milliseconds) to several minutes can be also covered by these techniques. In recent years, solution SAS techniques have had versatile applications in several research fields, especially in structural biology and in probing self-assembling nanomaterials. Probing the structure of materials at micro- and nano-scales provide an insight on the macroscopic properties of the material. The high throughput and fast time resolution offered by SAXS in combination with the neutron penetrating ability in SANS can offer a great potential to cover different soft-matter systems and processes (i.e. probing the kinetic of self-assembly). Here we review the solution SAS (both synchrotrons and Neutron Sources) capabilities which have been established in mainland China, and cover scattering theoretical developments. Recent advances in solutions SAS used in soft matter will also be discussed. Given the potential offered by the next generation X-ray and Neutron sources, further developments in this field are expected, with a proliferation of solution SAS applications.

Although enzyme catalysis has many advantages such as green, high efficiency and so on, the industrial application of enzyme is often hampered by a lack of long-term operational stability and difficult to re-use. These drawbacks can generally be overcome by immobilization of the enzyme on a solid carrier. However, the immobilized enzyme reactor often can not remain all the initial catalytic activity due to the enzyme shedding during reuse, change of conformation and the difficulty for substrates to access the active site of enzyme in the carrier, etc. The contradiction between catalytic activity and stability of biological enzyme molecules supported on solid phase carriers has become a bottleneck in the design and preparation of immobilized enzyme reactors. Therefore, it is a challenging task to construct an immobilized enzyme reactor with both high catalytic activity and high stability. In this work, aluminum-based metal-organic framework (Al-MOF)-derived hierarchical porous Al₂O₃ (MHAl₂O₃) was prepared by the self-sacrificial template strategy and functionally modified with “polydopamine (PDA)” bionic membrane for entrapping horseradate peroxidase (HRP). The pore size was regulated by changing the calcination temperature of precursor. The influence of channel confinement effect of the carrier on the catalytic activity of the enzyme reactor was discussed, and the thermal stability and reusability of the HRP@PDA@MHAl₂O₃ was significantly improved. After 1 h at 70 ℃, 98.5% of the catalytic activity of HRP@PDA@MHAl₂O₃ could be maintained. After 10 times of reuse, 90.9% of the catalytic activity was still maintained. In order to analyze the structure-activity relationship of the enzyme reactor, the interaction between enzyme and substrate in the reaction catalyzed by HRP@PDA@MHAl₂O₃ was studied by means of enzyme kinetics and thermodynamic parameters, which showed that the affinity and specificity of the enzyme to the substrate were improved. When the enzyme reactor was applied to the catalytic degradation of aniline aerofloat in simulated wastewater, the degradation rate of 40 mg•L^-1 substrate in 30 min reached 82.7% under the best reaction conditions.

The rise in global demand for green chemistry and sustainable development have driven immense research in the fundamental science of catalysis. Metal-free catalysis, serves as an ideal industrial technology, has emerged as a new frontier and hot point in modern catalysis science due to its green and sustainable properties. As a new carbonaceous material, graphene exhibits high surface area, excellent stability, unique mechanical and electronic properties. Its physical and chemical properties can be further modulated by modification and functionalization. Graphene derivatives have been successfully employed in a variety of chemical transformations recently, showing them to be promising metal-free organocatalysts. This review highlights the recent advancements of graphene-derived materials as metal-free carbocatalysts and their application in organic reactions, such as oxidation, reduction or hydrogenation, coupling, substitution, etc. The possible structure-performance relationships of graphene-based carbocatalysts and metal-free organocatalytic mechanisms are also emphasized.

Organic solar cells (OSCs) are among the most promising photovoltaic technologies to solve energy and environmental problems. To achieve highly efficient OSCs, controlling over electrode interfacial layers is greatly important for improving charge transportation and collection. Here, ternary metal oxide semiconductor films of Mg-doped NiO (NiMgO) have been prepared via a sol-gel method, and further optimized by several post-treatment strategies. The structures, properties and energy levels of different NiMgO films have been investigated to explore the influence of various post-treatment strategies. Incorporating the ternary NiMgO films as a novel type of hole transport layers (HTLs), non-fullerene OSCs have been fabricated based on a promising bulk-heterojunction of PM6:M36. Their photovoltaic performances and mechanisms of device physics are also investigated. When the sol-gel derived NiMgO film without post-treatment is used as an HTL, the OSCs show a relatively low power conversion efficiency (PCE) of 5.90%. By contrast, after simple ultraviolet-ozone (UVO) post-treatment on the NiMgO HTL, the resulted OSCs exhibit greatly enhanced photovoltaic performances, with an increased open-circuit voltage (V_OC) of 0.87 V and an improved PCE of 12.67%. More importantly, a new dual post-treatment combining surface rinse with UVO treatment has been demonstrated to further optimize NiMgO HTLs and improve device performances. The rinse process can remove excess impurities and flatten the surface of NiMgO films as well as increase the transmittance, while the UVO treatment process is beneficial for reducing surface defects of the ternary oxide films. Benefit-ing from such an efficient dual post-treatment on NiMgO HTLs, the OSCs afford a high PCE of 13.17% with a retained V_OC of 0.87 V, an increased short-circuit current density of 23.48 mA•cm^–2, and an improved fill factor of 64.29%. These results provide an effective way for surface post-treatment and property optimization of semiconducting metal oxide films, and contribute to the development of high-performance optoelectronic devices.

Pd single site catalysts (Pd SSCs) are recognized to be efficient for CO esterification to a valuable product, dimethyl carbonate (DMC), but the tendency of reduction to Pd nanoparticles in CO atmosphere under reaction process leads to a reduced selectivity and limits the industrial application. Hence, the development of appropriate supports to stabilize Pd single sites is of great importance. Metal-organic frameworks (MOFs) are expected to become one of the most ideal choices for supporting SSCs due to their large specific surface area, good stability, and ease of modification. Herein, a stable and highly modifiable MOF, UiO-66-NH₂, has been selected as the support. The pyridine-2-formaldehyde is grafted to UiO-66-NH₂ by post-synthetic modification, connecting to the skeleton of UiO-66-NH₂ via amine aldehyde condensation. In this way a pair of adjacent N atom sites are created to jointly chelate Pd(II) species, yielding Pd^II-UiO-66-X%. The Pd SSCs exhibit high DMC selectivity (>98%) in the CO esterification reaction. Moreover, Pd^II-UiO-66-X% shows excellent stability and more than 85% DMC selectivity can be maintained in 70 h continuous test, thanks to the good dispersion and strong interaction of Pd(II) species and the MOF support. As a control, the Pd(II) species is supported on ZrO₂ to give Pd^II/ZrO₂. Obviously, it is difficult for ZrO₂ to disperse Pd(II) species and to strongly interact with them due to the absence of binding groups. As a result, Pd^II/ZrO₂ is rapidly reduced by CO during the reaction, resulting in decreased DMC selectivity. In addition, the signals of key intermediates are detected and the reaction mechanism on Pd^II-UiO-66-X% is proposed based on in-situ diffuse reflectance infrared Fourier transform (in-situ DRIFT) spectra. The successful fabrication of Pd^II-UiO-66-X% with high selectivity and stability provides great opportunity for CO esterification to DMC.

The relevance of low-valent iron complexes bearing sulfur-containing ligands with the reactive iron intermediates in enzymatic dinitrogen fixation has stimulated great synthetic efforts toward them. Low-valent iron thiolate complexes have been mostly known for the thiolate-bridged diiron(I) carbonyl compounds. In contrast, isolable mononuclear iron(I) thiolate complexes are exceedingly rare. Herein, we report the synthesis and characterization of a mononuclear iron(I) complex [(IMes)Fe(SAr*)] (1, IMes=1,3-bis(mesityl)imidazole-2-ylidene, Ar*=2,6-(2',4',6'-Prⁱ₃C₆H₂)₂C₆H₃) as well as its catalytic performance in dinitrogen silylation reaction. Complex 1 was synthesized from the reaction of (IMes)₂FeBr with KSAr* in Et₂O in 81% isolated yield. Single-crystal X-ray diffraction studies revealed that the thiolate ligand in 1 is coordinating to the iron center in an σ:η⁶-fashion via the sulfur atom and one of the flanking Prⁱ₃C₆H₂ ring with the Fe—S distance of 0.2228(1) nm and the Fe—C(Trip) distances ranging from 0.2076(2) to 0.2205(2) nm. Zero-field ⁵⁷Fe Mössbauer spectrum at 80 K (δ=0.56 mm•s^-1; ΔE_Q=0.98 mm•s^-1) and X-band electron paramagnetic resonance data (g=[2.20, 2.03, 1.99]) at 103 K of 1 point to its low-spin iron(I) nature (S=1/2). These data are comparable with those of Holland's iron(I) thiolate complex K[(2-S-1,3-(6-F-3-(2,4,6-Prⁱ₃C₆H₂)C₆H₂)₂C₆H₄)Fe] (Nature 2015, 526, 96). Density functional theory studies support the S=1/2 ground spin-state for 1 and reveal that the interaction between the iron atom and the sulfur atom is essentially σ-bonding in character. In addition, π- and δ-type interactions between the iron atom and the η⁶-Prⁱ₃C₆H₂ ring in 1 also exist. Complex 1 can catalyze the reaction of N₂ with KC₈ and Me₃SiCl in Et₂O at room temperature, affording N(SiMe₃)₃ with a turn-over number up to 73 in 24 h and 87 in 48 h. The reaction employing (IMes)₂FeBr as catalyst has a turn-over number up to 73 in 24 h and elongating the reaction time to 48 h does not lead to further increase of the turn-over number. The fine catalytic performance with 1 over (IMes)₂FeBr implies that the thiolate ligand in 1 might render the catalytically active intermediate a relatively long lifetime.

The study of phosphine-protected gold nanocluster can be dated back to 1969, however, the RP-Au-PR motif has not been reported until now. Meanwhile, its analogue RS-Au-SR motif was often reported in thiolated gold nanoclusters, being of multiple functions (e.g., enhancing the luminescence). Herein, we successfully synthesized a monodisperse gold-silver nanocluster: [Au₁₀Ag₄(Dppp)₅Cl₄]Cl₂ (Au₁₀Ag₄ NC, where the Dppp represents 1,3-diphenylphosphine propane, and NC represents nanocluster) by introducing the reducing agent (NaBH₄) in an dichloromethane-ethanol solution of chloroauric acid, silver nitrate and 1,3-diphenylphosphine propane. Hydrochloric acid was added to promote the nanocluster size-focusing. Au₁₀Ag₄ NC is unstable in dichloromethane and will be transformed into another nanocluster [Au₉Ag₄(Dppp)₄Cl₄]Cl (Au₉Ag₄ NC). The structures and compositions of Au₁₀Ag₄ and Au₉Ag₄ NCs have been determined by single crystal X-ray crystallography and electrospray ionization mass spectrometry (ESI-MS). Au₁₀Ag₄ NC possesses an ico sahedral Au₉Ag₄ core, which is protected by a special RP-Au-PR motif, diphosphine and halogen ligands; Au₉Ag₄ NC has an icosahedral Au₉Ag₄ metal core protected by bisphosphine and halogen ligands, thus the major structural difference between Au₁₀Ag₄ and Au₉Ag₄ NCs is the RP-Au-PR motif. The motif can be self-vanished in Au₁₀Ag₄ NC when dichloromethane acts as the solvent, resulting in the formation of Au₉Ag₄ NC as mentioned above; on the other hand, the motif can self-bear in Au₉Ag₄ NC when the solvent is ethanol instead of dichloromethane, resulting in the formation of Au₁₀Ag₄ NC_. The two nanoclusters showed similar ultraviolet-visible-near infrared (UV/Vis/NIR) absorption spectra except for slight shift of the profile, indicating that the RP-Au-PR motif has no essential influence on the electronic structure of nanocluster, which was supported by density functional theory (DFT) calculations. However, the photoluminescence quantum yield of Au₁₀Ag₄ NC (10.32%) is 19 times higher than that of Au₉Ag₄ NC (0.52%), ascribing to the enhancement of charge transfer and structure rigidity induced by the motif. This work provides new views to the structure and photoluminescence of gold-silver nanocluster, has important implications for the structure-property understanding and the property improvement.

Organic semiconductor optoelectronic devices have made rapid development and progress in both research and industrial applications. The related directions have become a mature and emerging field. However, the organic materials in such devices usually are extremely sensitive to water vapor or oxygen existed in ambient air, which seriously affects the long-term stability of the devices. In addition to interface engineering, selecting appropriate charge (holes or electrons) transport layers and interfacial materials to improve the water and oxygen tolerance of the device and packing the device with robust encapsulation are all effective strategies to isolate the device from the water and oxygen in ambient air. Among various encapsulation technologies, atomic layer deposition (ALD) is an almost perfect encapsulation approach, which could deposit thin films in the layer-by-layer growth mode at low-temperature, with the characteristics of accurate and controllable thickness, high repeatability, excellent uniformity and high density. These characteristics make ALD to be widely used in semiconductor industry. Here, we review the progress of the applications of the ALD encapsulation techniques in organic light emitting diode (OLED) and provide further discussions on the enlightening significance of ALD encapsulation techniques in organic photovoltaics (OPV) and perovskite solar cell (PSC) encapsulations.

Cucurbit[n]uril (Q[n]) is a relatively new supramolecular macrocyclic compound, which has a unique structure comprised of a hydrophobic cavity with intermediate potential, two carbonyl portals with negative potential, and an outer surface with positive potential. Cyclohexyl-substituted Q[n]s have also attracted a lot of attention as the first member of the Q[n] family that can be dissolved in organic solvents and water. In this paper, the interaction modes between the symmetric dicyclohexanocucurbit[6]uril (CyH₂Q[6]) as a host and nicotinic hydrazide (NH) as a guest were investigated by nuclear magnetic resonance spectroscopy (¹H NMR), isothermal titration calorimetry (ITC), matrix assisted laser desorption ionization time of flight (MALDI-TOF) mass spectrometry, and single-crystal X-ray diffraction. The ¹H NMR spectrum results showed that the proton peaks shift to the downfield, indicating that NH is located at the portal of CyH₂Q[6]. ITC experiment results showed that the binding constant (K_a) of NH@CyH₂Q[6] is (1.019±0.118)×10³ L•mol^-1, the host-guest binding ratio is 0.954±0.013, and the enthalpy value is ΔH=(–48.21±0.35) kJ•mol^-1 and entropy value TΔS=(–31.04±0.52) kJ•mol^-1. The MALDI-TOF mass spectrum also showed that the molecular ion peak m/z is 1242.4542 (theoretical value: 1242.1603), which is attributed to [CyH₂Q[6]•HNH]⁺. These experimental results showed that CyH₂Q[6] formed a stable 1∶1 exclusion complex with NH in an aqueous solution. In addition, the host CyH₂Q[6], ZnCl₂ and the guest NH were added to HCl aqueous solution, and the complex single-crystal structure was obtained by evaporation and standing. The single-crystal structure of the complex showed that there are ion-dipole interactions and hydrogen bonds between the carbonyl oxygen of CyH₂Q[6] and NH, and there are ion-dipole interactions between the outer surface of CyH₂Q[6] and [ZnCl₄]^2-. These weak interactions are the driving forces of the multi-dimensional and multi-level supramolecular framework formed by the complex.

11-Chloro-1,1'-di-n-propyl-3,3,3',3'-tetramethyl-10,12-trimethyleneindatricarbocyanine iodide (IR-780) is a near infrared (NIR) photosensitizer for cancer treatment. Under NIR irradiation, IR-780 efficiently generates singlet oxygen or other reactive oxygen species (ROS) in lesion position that ultimately cause cell apoptosis and necrosis. However, biomedical application of IR-780 was limited by its poor water solubility. In this work, we designed a water-soluble IR-780 polymer (Poly-IR) for mitochondria-targeted photodynamic therapy via condensation polymerization. The results of dynamic light scattering (DLS) and transmission electron microscope (TEM) displayed that Poly-IR was self-assembled into nanoparticles in water. And ROS detection experiments demonstrated that Poly-IR quickly and efficiently generated ROS under NIR irradiation in solution and cells. The cellular distribution of the Poly-IR was monitored by confocal laser scanning microscopy (CLSM). Colocalization experiments with mitochondrial stain revealed a high degree of colocalization between Poly-IR and mitochondria, which illustrated that Poly-IR selectively accumulated in mitochondria. Furthermore, we explored the photodamages of Poly-IR to mitochondria through monitoring the change of mitochondrial membrane potential that was stained by JC-1 probe. In the dark, red fluorescence emerged with Poly-IR treated A549 cells. Under NIR irradiation, the red fluorescence was disappeared and green fluorescence was generated in Poly-IR treated cells, which confirmed the photodamage of Poly-IR to mitochondria. The cytotoxicity of Poly-IR was measured by MTT assay (MTT=3-(4,5-dimethylthiazol- 2-yl)-2,5-diphenyltetrazolium bromide). The IC₅₀ values of Poly-IR for A549 cells and MCF-7 cells were 9.13 and 10.98 μg/mL respectively in the dark. At the same time, the IC₅₀ values of Poly-IR for A549 cells and MCF-7 cells were 4.57 and 0.22 μg/mL respectively under NIR irradiation. The cytotoxicity of Poly-IR for MCF-7 cells treated with NIR exposure was significantly increased 50 times compared to without irradiation. Live/dead cell staining experiments also verified that Poly-IR had more phototoxicity. Meanwhile, cytotoxicity on tumor cells was also detected by flow cytometry apoptosis assay according to the typical Annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) double staining principle. These results suggested that Poly-IR promoted tumor cells apoptosis under near-IR irradiation, which expanded ideas in mi-tochondria-targeted photodynamic therapy in cancer treatment.

Red emitter is one of the three primary materials for display, which is widely used in full-color display, biosensing and photodynamic therapy due to the advantages of small emission energy, strong penetrating ability and low background fluorescence interference. At present, the main bottlenecks for the development of red emitters are as follows. (1) The narrow energy gaps of red emitters often lead to serious non-radiative transition and low quantum efficiency. (2) The largely conjugated structure of red emitters results in strong π-π stacking for emission quenching. (3) Molecular design requires greater conjugation, which is difficult in molecular synthesis. Red thermally activated delayed fluorescence (TADF) materials, as a new type of red emitters, can use triplet excitons to release fluorescence through reverse intersystem crossing process, which greatly improves the quantum efficiency. Therefore, red TADF materials have become a hot topic in recent years. Because of the structural advantages, quinoxaline and its derivative are promising building blocks for the construction of red TADF emitters. The research progress of the quinoxaline-based red TADF materials in recent years is summarized, the influence of molecular structure on the properties of materials is discussed, and the prospect is also provided.

Organic light-emitting transistor (OLET) is a kind of revolutionary miniaturized optoelectronic device which integrates the functions of an organic field-effect transistor and an organic light-emitting diode in a single device. This unique integrated architecture of OLET makes it show great potential for studies of fundamental properties of organic materials, applications in fields of novel organic flexible display/lighting technology, organic electrically-pumped lasers as well as on-chip optoelectronic systems. To realize the full potential of these technologies, the development of key materials and optimization of device fabrication techniques including device structures and processing conditions are highly required. Based on the comprehensive study of the development and basic scientific problems in the OLET field, in the past five years, the authors' research group and collaborators carried out systematical exploratory researches with focuses on the development of high mobility emissive organic semiconductors and construction of high performance OLETs with line- and area-feature emission. Up to now, a series of achievements have been obtained. For instance, we developed a series of anthracene- and fluorene-based high mobility emissive organic semiconductors from the origin of molecular design innovation, which overcomes the science bottleneck of impossibility for integrating high charge carrier mobility and strong emission in the same molecule. Furthermore, this molecular design concept also shows a certain feasibility for the development of other small molecular systems and high mobility emissive conjugated polymers. Moreover, with the mind of integrating the advantages of area-emission of vertical OLET and good gate-tunability and stability of planar OLET, we propose a new area-emission planar OLET architecture, which exhibits a large aperture ratio of over 80% due to the arbitrary tunability of device structure. These preliminary experimental researches and results will provide valuable guidelines for future research of OLETs and their related fields.

Environmental pollution is one of the most severe problems facing the earth today, including water pollution and the greenhouse effect caused by the indiscriminate discharge of organic dyes and abundant carbon dioxide emissions (CO₂), respectively. Therefore, removing dyes from water and eliminating CO₂ in the atmosphere is an urgent issue that needs to be solved. Among them, with low cost and high adsorption efficiency, porous materials have become one of the most common materials to adsorb organic dyes and uptake CO₂. Covalent organic frameworks (COFs), as a burgeoning class of crystalline porous polymers, present a promising application potential in many areas, such as gas adsorption and separation, heterogeneous catalysis, semiconductors and sensors due to their regular pores, modifiable frameworks, extensive specific areas and excellent stability. Especially the introduction of the functional groups to the skeleton of COFs provides abundant active sites to adsorb specific dyes and uptake gases. Inspired by this, we report a microporous COF (JUC-603, JUC=Jilin University China) decorated with sulfonic acid group. This COF was successfully synthesized through β-ketoenamine based Michael addition-elimination reaction of 1,3,5-tris(3-dimethylamino-1-oxoprop-2-en-yl)benzene (TDOEB) and p-phenylenediamine (PPDA). A series of characterizations proved that JUC-603 had high crystallinity, opening microporous pore and excellent stability. Nitrogen adsorption-desorption isotherm revealed a high Brunauer-Emmett-Teller (BET) surface area (774 m²/g) and large pore size (1.6 nm). Moreover, we studied the adsorption of JUC-603 on dyes from aqueous solutions by ultraviolet- visible spectrophotometry and the uptake capacity through CO₂ adsorption-desorption. These results showed that JUC-603 could selectively adsorb cationic dyes such as crystal violet and methylene blue as well as uptake CO₂ effectively (52 cm³/g at 273 K and 0.1 MPa). The ideal performance was attributed to the modulation of active sulfonic acid sites on the framework of JUC-603. This research thus indicates that the COF as a promising functionalized porous material has great potential in environmental remediation.

Hypervalent iodine reagents, as a type of environmentally friendly and economical oxidants, have received extensive attention from synthetic chemistry in recent years. There are two kinds of common hypervalent iodine reagents: iodine(III) and iodine(V) reagents. Among various iodine(V) based reagents, 2-iodoxybenzoic acid (IBX) is one of the most commonly used oxidants in organic chemistry and has been widely used in selective oxidation of phenols, alcohols, thioethers and many other compounds. Although the IBX can efficiently oxidize electron-rich phenols to obtain o-quinones, which have important applications in catalysis and materials science, the synthesis of electron-deficient o-quinones is still challenging and remains an unsolved problem. Recently, a novel bidentate nitrogen-ligated iodine(V) reagent has been found to efficiently and selectively promote the oxidative dearomatization of electron-deficient phenols to o-quinones. The bidentate-nitrogen ligand has been demonstrated to play a crucial role in the successful oxidative dearomatization of electron-deficient phenols. To understand the origin of the effect of bidentate-nitrogen ligand on oxidative dearomatization, we herein conducted a detailed mechanistic study on the oxidative dearomatization of phenols promoted by iodine(V) reagents with different ligands by using density functional theory (DFT). Geometry optimizations and frequency calculations were carried out at the M06-2X/[6-31G(d,p)+LANL2DZ(I)] level of theory. To obtain more accurate electronic energies, single-point energy were calculated at the M06-2X/[6-311+G(2d,p)+def2-TZVPP(I)] level of theory. The solvation model based on density (SMD) was used to account for the solvation effect of chloroform, the solvents used in the experiment. Calculations revealed that the bidentate-nitrogen ligand not only enhances the reactivity of iodine(V) reagent but also acts as a base to neutralize the strong acid generated in the reaction to prevent product degradation. The insights into the effect of the bidentate-nitrogen ligand on the reactivity of hypervalent iodine reagent obtained from this study would facilitate the future design of novel ligand- regulated hypervalent iodine reagents for new reactions.