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Selective isomerization of terminal olefins to afford new internal olefins is an atom economic reaction that is usually catalysed by metal catalysts. Here, we present a tris(pentafluorophenyl)borane [B(C6F5)3]-catalysed isomerization of olefins. Linear α-olefins are converted to 2-olefins in high yields with unsatisfactory stereoselectivity under the applied reaction conditions. At the same time, the biorelevant phenylpropenoid products can be obtained with high regio- and stereoselectivity from the isomerization of allylbenzenes. [ABSTRACT FROM AUTHOR]

We have successfully prepared a metal–organic-framework (MOF) derived In2O3 flower-like hierarchical architecture sensor using a near room-temperature template-free strategy and a subsequent accurate annealing process. The In2O3 flower-like hierarchical architecture sensor exhibits good sensitivity to trimethylamine. The fabricated sensor has a relatively low working temperature of 140 °C, a response of 35.2 for 20 ppm trimethylamine, a response time as fast as 2 s, and good selectivity and stability. In addition, the sensor exhibits good conductivity. The sensor's enhanced gas sensing performance can be attributed to the synergistic effect of its unique flower-like hierarchical architecture, porous hierarchical morphology and abundant oxygen vacancies. Furthermore, the possible growth mechanism and the gas sensing mechanism are also discussed in detail. [ABSTRACT FROM AUTHOR]

Urease is a nickel-containing oligomer that can be used to catalyze the decomposition of urea. Free urease is unstable and prone to inactivation, whereas the immobilization of urease improves its resistance to environmental changes. A green and harmless cyclodextrin polymer (CDP) that has a network structure and excellent modifiability was selected for the immobilization of urease. Citric acid cross-linked CDP (CACDP) is oxidized by sodium periodate to obtain the aldehyde-functionalized dialdehyde CDP (DACDP). Urease is covalently bound to the CDP through a Schiff base reaction between the amino groups and aldehyde groups on DACDP to obtain urease-immobilized CDP (UrCDP). A series of characterization methods and urea-removal experiments confirmed the successful immobilization of urease on the polymer and thus the good removal effect. The maximum removal capacities of UrCDP34-6, UrCDP34-4, and UrCDP34-2 for urea are 145.7 mg g−1, 242.9 mg g−1 and 291.1 mg g−1, respectively. Urea-removal experiments at different temperatures and pH values proved that UrCDP maintains its catalytic activity in response to environmental changes. At the same time, a simple continuous-flow treatment device proved that UrCDP has the clear ability to continuously remove urea. This effective urease-immobilization and urea-removal method is experimentally proven and envisions potential applications in medical and wastewater treatment. [ABSTRACT FROM AUTHOR]

Mg and Al dual-metal functionalized nanoscale porous carbon materials (MgAl@NC) with highly ordered mesoporous structures and mixed active sites were successfully prepared using a simple one-pot synthesis method. The catalytic properties of the resultant MgAl@NC catalysts were investigated for the synthesis of ethyl methyl carbonate (EMC) in a fixed bed reactor. The catalysts exhibited remarkably high activity, selectivity and stability for the transesterification of diethyl carbonates (DEC) with dimethyl carbonates (DMC) even under high LHSV conditions. A 50.0% DEC conversion and a 99.2% EMC selectivity could be obtained at 103 °C and an LHSV = 7.8 h−1. The catalyst maintained a high product yield with almost no decrease in catalytic performance after 360 h. The well-dispersed magnesium aluminate spinel and α-cristobalite formed neighboring acid–base sites, while the synergistic catalytic effects of the mixed active sites should be critical for activation of the reactants. It may also be the reason for the efficient production of EMC under very high LHSV conditions. [ABSTRACT FROM AUTHOR]

Herein, small Co nanoparticles (NPs) encapsulated in N-doped double-shelled carbon nanocages grafted with thin carbon nanotubes (Co@CNTs@DSCNCs) were synthesized from yolk–shell bimetallic zeolitic imidazolate framework (BMZIF). For HER electrocatalysis, they exhibit higher activity (η10 = 214 mV) and more favorable kinetics than Co@CNTs@PC (PC = porous carbon) with thick CNTs and large Co NPs derived from solid BMZIF cubes. [ABSTRACT FROM AUTHOR]

A new ratiometric fluorescent probe, namely TPE-RNS, has been developed for detecting intracellular HClO/ClO− in living cells and discriminating cancer cells from normal cells. Based on the ratiometric fluorescence properties conferred by the AIE and DTBET effects, this probe has excellent sensitivity and specificity for the HCIO response. [ABSTRACT FROM AUTHOR]

Lithium–sulfur batteries are promising energy storage systems because of their high energy density and cost-effectiveness. However, their practical application is hampered due to rapid capacity degradation and low areal capacity induced by the shuttling of intermediate polysulfides and slow reaction kinetics. The host material plays a critical role in enhancing cycling stability and rate capability. Here, we reported a simple and scalable strategy to construct a rich nitrogen-doped carbon-based host with a three-dimensional (3D) hierarchical porous network and interconnected microchannels. Specifically, both channels and porous structure could be regulated by adjusting the ratio of polyacrylic acid to polyacrylonitrile in the precursor. The nitrogen-doped porous carbon network effectively suppressed the translocation of the polysulfide and triggered fast redox kinetics resulting from the fast charge transfer at the interface between the electrode and electrolyte. Taking advantage of the hierarchical porous architecture design, the nitrogen-doped porous carbon framework/sulfur composite electrode delivered high initial discharge capacity of 1228 mA h g−1 with 81.9% capacity retention and low capacity decay of 0.06% after 300 cycles. Even at a high sulfur loading of 6.5 mg cm−2, the electrode still achieved capacity retention of 65.1% and a lower capacity fading rate of 0.069% per cycle after 500 cycles at 1C. In particular, this hierarchical porous network structure opens a new avenue to develop an electrode with high energy density and long life for electric storage applications. [ABSTRACT FROM AUTHOR]

In this study, we design and synthesize a novel photosensitive polyurethane material as a functional dielectric layer, which can adjust the crystallization of para-hexaphenyl (p-6P). The novel polymer is synthesized with a new monomer 2,2-bis(hydroxymethyl)butyl 4-cyanobenzoate (HM-4-CB), which contains benzene to provide crystal nucleus sites. The grain size and density of the p-6P crystal can be controlled by the content of HM-4-CB in the polymer structure. Therefore, this method can be used to regulate the grain size of semiconductor crystals and then to change the carrier mobility of the device. The results illustrate that with a suitable grain size of the p-6P semiconductor, excellent performance in terms of charge carrier mobility can be obtained. [ABSTRACT FROM AUTHOR]

We report a supersandwich fluorescence in situ hybridization (SFISH) strategy for highly sensitive and selective in situ visualization of mRNA expression patterns at the single-cell level. This strategy uses two fluorophore-labeled signal probes to generate a supersandwich product, which in turn generates numerous signal probes located at the target mRNA position, resulting in the in situ fluorescence signal amplification. [ABSTRACT FROM AUTHOR]

An ambient method for rapid monitoring and quantitation of drugs of abuse in dried blood spots was developed using paper spray tandem mass spectrometry (PS-MS). [ABSTRACT FROM AUTHOR]

We presented a homogeneous heparin-mediated fluorescence anisotropy (FA) assay of antithrombin (AT) based on long-lived luminescent polyethyleneimine capped Mn-doped ZnS (PEI-Mn-ZnS) QDs. The PEI-Mn-ZnS QDs with long lifetime luminescence at 585 nm displayed a very low background of FA value, which was very helpful for FA assaying of large molecules. The medium heparin was crucial for AT determination, and different heparin amounts resulted in different linear range of detection and sensitivity. For example, the limit of detection (LOD) of 0.9 nM AT with a detection linear range from 8.6 nM to 21.5 nM was found when the heparin concentration was 75 μM. The proposed method also exhibited high selectivity over the coexisting or related proteins such as human serum albumin and thrombin. [ABSTRACT FROM AUTHOR]

Transitional metal oxide nanoparticles and carbon composites have attracted tremendous research interest due to their potential as anode materials in next-generation lithium-ion batteries (LIBs). Herein, porous Mn3O4/carbon nanofibers (Mn3O4/CNFs) are designed and synthesized via electrospinning in combination with an in situ growth method followed by subsequent multi-step heat treatments. As an anode for LIBs, Mn3O4/CNFs-2 exhibits good cyclability with high reversible capacity. A reversible capacity of 754 mA h g−1 over 400 cycles at a current density of 0.1 A g−1 is achieved. The presence of CNFs can improve the conductivity of the electrode material and relieve the volume expansion of Mn3O4 during the process of Li+ insertion and extraction. Meanwhile, a small amount of N atom doping can enhance the reaction kinetics and Li+ pseudocapacitive behavior while providing reversible capacity and long cycling performance. Quantitative analysis shows that mixed diffusion-controlled and capactive behavior control mechanisms account for the Li+ storage, wherein the pseudocapacitive behavior can contribute to additional capacity. [ABSTRACT FROM AUTHOR]

The sludge from a sewage treatment plant was used as the raw material, the plant ash was used as the activator, urea was used as the modifier and the sludge was used to prepare the sludge carbon material. Orthogonal tests were designed to determine the best preparation conditions for the samples. The structure and deodorization products of sludge carbon were analyzed by SEM, FT-IR, XPS, specific surface area and pore structure analyses. The results showed that the sludge carbon T550U1.5t60SAC had the best deodorization performance when the pyrolysis temperature was 550 °C, the stucco/drug ratio was 1 : 1.5, and the pyrolysis time was 60 min under N2 atmosphere. The penetration time for hydrogen sulfide and methyl mercaptan reached 200 min and 100 min, respectively. Structural analysis showed that the T550U1.5t60SAC carbon material had a rough surface and wide pore diameter distribution. It not only had oxygen-containing functional groups on the surface, but the concentration of the nitrogen-containing functional groups on the surface also increased with the addition of urea, and the surface alkalinity of the material increased. These factors provided channels and activity points for the adsorption of H2S and CH3SH. The surface area and pore size distribution of the adsorbed T550U1.5t60SAC sludge changed significantly, particularly after the micropores disappeared. This indicated that the deodorization reaction mainly occurred in the micropores, and deodorized products such as elemental sulfur and sulfate appeared. The analysis suggested that the ˙OH radical on the surface of sludge carbon was the main species for the oxidation of H2S and CH3SH. [ABSTRACT FROM AUTHOR]

A new strategy for the rapid construction of functionalized reduced indoles starting from activated methylene isocyanides and 1,5-dielectrophilic 5-oxohepta-2,6-dienoates (and their equivalents) through a [5+1] annulation–isocyanide cyclization cascade under basic conditions has been developed. This strategy allows the synthesis of polysubstituted dihydroindolones and tetrahydroindolones in high to excellent yields under extremely mild conditions in a single step. [ABSTRACT FROM AUTHOR]

A specific resonance light scattering bioassay for homocysteine is developed on the basis of target-involved assembly of polyethyleneimine-capped Ag-nanoclusters. The bioassay permits discriminating homocysteine from cysteine, glutathione and other amino acids, and allows sensitive and selective detection of homocysteine with a detection limit of 42 nM. [ABSTRACT FROM AUTHOR]

Non-polar solvents like hexane allow ionization of insoluble drugs, peptides, nucleotides and phospholipids as solids from paper. Ambient ionization is achieved simply by application of a high voltage to the wet paper. Transport and ionization mechanisms are discussed, including the possibility of field desorption from dendritic structures formed on the paper. [ABSTRACT FROM AUTHOR]

Based on the internal filtration effect between upconversion nanoparticles and square acid-FeIII(SA-FeIII), this method was developed for the rapid identification of total antioxidant capacity of different fruits without complex modification on the surface of upconversion nanoparticles. The near-infrared light excitation of rare-earth upconversion can effectively avoid food fluorescence and the photobleaching effect; thus, the components to be detected in the samples can be monitored real time without a complex extraction process. Due to the instability of the antioxidants at room temperature, the short time required for this reaction (6 min) will facilitate the study of the true antioxidant power of the samples. This method is simple and responds well to the main antioxidants of fruits and vegetables with a detection limit of 0.1 μmol L−1, such as ascorbic acid, polyphenols, and anthocyanin, and it shows good linearity in the concentration range of 0–1.0 mmol L−1. [ABSTRACT FROM AUTHOR]

Surface-enhanced Raman scattering (SERS) on organic–inorganic hybrid perovskites is explored and for the first time the SERS activity (EF ≥ 104) of the nanostructured CH3NH3PbBr3 has been proved. Here, the SERS profile displays high similarity with the normal Raman spectra and the enhancement mechanism is discussed according to the charge transfer contribution. [ABSTRACT FROM AUTHOR]

A general visible-light-induced catalyst-/additive-free strategy was developed for the construction of various aroylated heterocycles (55 examples, up to 95% yield, including modification of pharmaceuticals and natural products) such as thioflavones, benzimidazo[2,1-a]isoquinolin-6(5H)-ones, indolo[2,1-a]isoquinolin-6(5H)ones, quaternary 3,3-dialkyl 2-oxindoles, quinoxalin-2(1H)-ones, and benzo[e][1,2,3]oxathiazine 2,2-dioxides in a green solvent (dimethyl carbonate) under air and room temperature conditions. This practical acylation process was achieved using 4-acyl-1,4-dihydropyridines (acyl-DHPs) as acylating reagents under mild conditions, avoiding the use of catalysts, bases, additional oxidants, and traditional organic solvents. [ABSTRACT FROM AUTHOR]

Herein, we have developed a rhodium-catalyzed C–H functionalization and subsequent intramolecular ring-opening/cyclization of vinylene carbonate with 2-pyrrolyl/indolylanilines, which leads to oxazolidinones in moderate to good yields. In this transformation, vinylene carbonate only eliminates one oxygen atom rather than –CO3 or CO2. Furthermore, some control experiments are conducted to elucidate the reaction mechanism. [ABSTRACT FROM AUTHOR]

Research on highly efficient nitrogen and sulfur co-doped carbon materials is crucial for the development of Fe-based non-noble metal electrocatalysts (NNMEs) as alternatives to platinum-group metal-based electrocatalysts for the oxygen reduction reaction (ORR) in fuel cells. In this work, complexes were derived from iron salt and biomass ligands, subsequently mixed with active carbon nanoparticles (NPs) and pyrolyzed at 800 °C to obtain the resulting electrocatalysts Fe/NSC (800) and Fe/NC (800). Through screening the synthetic parameters, it was found that the N and S co-decorated Fe-based electrocatalyst of Fe/NSC (800) displays better ORR performances in terms of the onset potential (Eonset) and the half-wave potential (E1/2) than those of the Fe-free electrocatalyst of NSC (800) and the N-doped electrocatalyst of Fe/NC (800). The improved ORR activity can be mainly ascribed to the FeN4 active sites, as well as the additional S-doping within the carbon matrixes. Additionally, Fe/NSC (800) displays good durability superior to that of 20 wt% Pt/C in 0.1 M KOH solution. This synthetic approach is beneficial for the synthesis of NNMEs with biomass ligands for boosting the ORR performances in an alkaline solution. [ABSTRACT FROM AUTHOR]

Three kinds of microstructures were prepared for one organic phosphor based on a solution-concentration-controlled self-assembly strategy. These microstructures show different phosphorescence efficiencies, which holds considerable promise for the miniaturized optical device applications of ultralong organic phosphorescence materials. [ABSTRACT FROM AUTHOR]

Convenient reading out and/or determination of ionic strength (IS) is of great significance for both scientific research and real life applications. We presented here a novel method for the rapid and sensitive IS assay based on the electrolyte-induced sensitive wavelength blueshifts of the reflection spectra of polyacrylate capped Fe3O4 magnetic photonic crystals (PA–Fe3O4-MPCs). For HCl, MgSO4 and the common electrolytes corresponding to the salinity of seawater (including NaCl, KCl, MgCl2, CaCl2, Na2SO4 and their mixtures), the PA–Fe3O4-MPCs displayed wavelength blueshifts identical to the total IS of the aqueous solutions, regardless of the kind of above-mentioned electrolytes in the solutions. Besides, the PA–Fe3O4-MPCs exhibited relatively high sensitivity (an average of 294 nm L mmol−1 in the range of 0.05–0.30 mmol L−1, and an even higher value of 386 nm L mmol−1 at 0.05–0.15 mmol L−1) and fast response (within 8 s) to the IS of aqueous solutions. The relative standard deviation (RSD) for IS (NaCl, 0.1 mmol L−1) was 4.4% (n = 5). The developed method was applied to determine the salinity of seawater samples, and the determined results were validated by the traditional standard chlorinity titration and electric conductimetry method. The recoveries were in the range of 92–104%. The proposed PA–Fe3O4-MPCs based reflectometry method would have great potential for IS and salinity assays. [ABSTRACT FROM AUTHOR]

We fabricate a cellulose sponge with stable superoleophobicity (ϑoil ＞ 150°) under water and superhydrophilic wettability (ϑwater≈ 0°) under oil without any further chemical modification for oil–water emulsion separation. The cellulose sponge shows superoleophobicity to various oils under water and possesses stable superoleophobicity in corrosive liquids like strong acid, alkali and salt solution. The sponge is made from the dissolution and regeneration of cellulose powder which is green, low cost, simple and easy to scale up. The natural hydrophilicity of the cellulose ensures its excellent under-water superoleophobicity and antifouling properties. The double layer construction of different pore sizes, which contains a top-layer with a pore size lower than 1 μm and a sub-layer with a pore size larger than 3 μm, ensures that the oil phase is resisted and the water phase easily and quickly permeates the sponge. Our cellulose sponge can separate oil–water mixtures, with ＞99.94% separation efficiency, solely using gravity and has excellent antifouling properties. [ABSTRACT FROM AUTHOR]

Developing green-safe, efficient and recyclable catalysts is crucial for the chemical industry. So far, organic photocatalysis has been proved to be an environmentally friendly and energy-efficient synthetic technology compared with traditional metal catalysis. As a versatile catalytic platform, hyper-crosslinked polymers (HCPs) with large surface area and high stability are easily prepared. In this report, we successfully constructed two porous HCP photocatalysts (TZ-HCPs) featuring s-tetrazine units and surface areas larger than 700 m2 g−1 through Friedel–Crafts alkylation reactions. The rational energy-band structures and coexisting micro- and mesopores endow TZ-HCPs with excellent activities to realize the green synthesis of benzimidazoles (28 examples, up to 99% yield, 0.5–4.0 h) in ethanol. Furthermore, at least 21 iterative catalytic runs mediated by TZ-HCP1D were performed efficiently, with 96–99% yield. This study of TZ-HCPs sheds light on the wide-ranging prospects of application of HCPs as metal-free and green photocatalysts for the preparation of fine chemicals. [ABSTRACT FROM AUTHOR]

A novel copper-catalyzed domino reaction between o-alkenyl aromatic isocyanides and diazo compounds has been developed under mild reaction conditions. Various o-alkenyl aromatic isocyanides were prepared from readily available reactants. The reaction provides a general and efficient method for the synthesis of pyrazolo[1,5-c]quinazolines by the formation of two rings and three new bonds in a single step from readily available acyclic starting materials. A mechanism involving a tandem (3+2) cyclization/elimination/intramolecular aza-addition sequence was proposed. [ABSTRACT FROM AUTHOR]

Grazing-incidence X-ray diffraction and rocking scans have quantified the structure of poly(3-hexylthiophene) and [6,6]-phenyl-C61-butyric acid methyl ester in the active layers of organic solar cells. Our study reveals that the device JSCcorrelates with the local structural development of pure PCBM and, to second order, the extent of out-of-plane P3HT π-stacking. [ABSTRACT FROM AUTHOR]

Correction for 's-Tetrazine-functionalized hyper-crosslinked polymers for efficient photocatalytic synthesis of benzimidazoles' by Wan-Kai An et al., Green Chem., 2021, 23, 1292–1299, https://doi.org/10.1039/d0gc03719b. [ABSTRACT FROM AUTHOR]

Due to its low cytotoxicity, high resistance to enzymatic degradation, and cellular permeability, a DNA tetrahedron-based molecular beacon (DTMB) is designed for tumor-related TK1 mRNA detection in living cells, where the target sequence can induce the tetrahedron from contraction to extension, resulting in fluorescence restoration. [ABSTRACT FROM AUTHOR]

Herein we introduce an enzyme-free and amplified colorimetric detection strategy, which is based on gold nanoparticle (AuNP) aggregation through target-catalytic DNA circuits (HCR and CHA). [ABSTRACT FROM AUTHOR]

Four 1,3-benzenedicarboxylic acid derivatives, with substituted R (OH, COOH, NO2, Me) groups at the 5-position, were employed to explore their effect on the construction of supramolecular assemblies. Four coordination polymers, [Zn(OH2)(5-HO-1,3-BDC)(1,4-bpeb)]n(1), [Zn(1,3,5-HBTC)(1,4-bpeb)]n(2), {[Zn(5-NO2-1,3-BDC)(1,4-bpeb)]·2(H2O)0.5}n(3), and [Zn(5-Me-1,3-BDC)(1,4-bpeb)]n(4) (1,4-bpeb = 1,4-bis[2-(4-pyridyl)ethenyl]benzene, 5-HO-1,3-BDC = 5-hydroxy-1,3-benzenedicarboxylate, 1,3,5-H3BTC = 1,3,5-benzenetricarboxylate, 5-NO2-1,3-BDC = 5-nitro-1,3-benzenedicarboxylate, 5-Me-1,3-BDC = 5-methyl-1,3-benzenedicarboxylate) were prepared by the hydrothermal reactions of Zn(NO3)2·6H2O with 1,4-bpeb and 5-HO-1,3-H2BDC, 1,3,5-H3BTC, 5-NO2-1,3-H2BDC or 5-Me-1,3-H2BDC. All these compounds were characterized by elemental analysis, IR, powder X-ray diffraction, and single-crystal X-ray diffraction. The structure of 1has a 3D H-bonded structure derived from linking 1D comb-like [Zn(OH2)(5-HO-1,3-BDC)(1,4-bpeb)]nchains viaintermolecular H-bonding interactions between the coordinated H2O molecule and 1,4-bpeb or one COO−group and between the OH group and the other COO−group. 2has a 3D H-bonded net based on holding 2D [{Zn2(1,3,5-HBTC)2}4]nlayers through intermolecular H-bonding interactions between 1,4-bpeb and the uncoordinated COOH group. 3could be considered as a 6-fold interpenetrating 3D H-bonded supramolecular framework constructed by linking 2D [Zn4(5-NO2-1,3-BDC)4(1,4-bpeb)4]nnetworks through intermolecular H-bonding interactions between the water solvent molecules and the NO2group. 4has a 3-fold interpenetrating 3D framework in which each 2D (4,4) [Zn4(5-Me-1,3-BDC)4(1,4-bpeb)4]nnetwork is interpenetrated by two other equivalent nets. The Schläfli symbols for the four supramolecular frameworks are 41263, (4·62)2(426687), (63)(658) and 4462, respectively. The thermal stability and photoluminescent properties of 1–4were also investigated. [ABSTRACT FROM AUTHOR]