Synthesis and Crystal Structure of Ethyl 2-(6-(1,3-Dioxo-4,5,6,7-tetrahydro-1H-isoindol-2(3H)-yl)-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4(3H)-yl) Butanoate

The title compound ethyl 2-（6-（1,3-dioxo-4,5,6,7-tetrahydro-lH-isoindol-2（3H）- yl）-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4（3H）-yl） butanoate 3 was synthesized by the reaction of ethyl 2-（6-amino-7-fluoro-3-oxo-2H-benzo[b][1,4]oxazin-4（3H）-yl） butanoate with 4,5,6,7- tetraydrophthalic anhydride, and its structure was determined by X-ray single-crystal diffraction. The crystal belongs to the monoclinic system, space group P2 1/n with a = 9.3469（2）, b = 16.7715（5）, c = 13.7153（4） A, β= 104.9680（10）°, μ = 0.107 mm^-1, Mr = 430.42, V= 2077.08（10） ,A3, Z= 4, Dc = 1.376 g/cm3, F（000） = 904, T= 296（2） K, R = 0.0508 and wR = 0.1478.

Chemical biology investigation of a triple-action,smart-decomposition antimicrobial booster based-combination therapy against“ESKAPE”pathogens

The global antibiotic resistance crisis necessitates urgent solutions.One innovative approach involves potentiating antibiotics and non-antibiotic drugs with adjuvants or boosters.A major drawback of these membrane-active boosters is their limited biocompatibility,as they struggle to differentiate between prokaryotic and eukaryotic membranes.This study reports the chemical biology investigation of a dual-action oligoamidine(OA1)booster with a glutathione-triggered decomposition mechanism.OA1,when combined with other antimicrobial molecules,exhibits a triple-targeting mechanism including cell membrane disruption,DNA targeting,and intracellular enzyme inhibition.This multi-targeting mechanism not only enhances the in vitro and in vivo eradication of antibiotic-resistant“ESKAPE”pathogens,but also suppresses the development of bacterial resistance.Furthermore,OA1 maintains its activity in bacterial cells by creating an oxidative environment,while it quickly decomposes in mammalian cells due to high glutathione levels.These mechanistic insights and design principles may provide a feasible approach to develop novel antimicrobial agents and effective anti-resistance combination therapies.

Sustainable silicon anodes facilitated via a double-layer interface engineering: Inner SiOx combined with outer nitrogen and boron co-doped carbon

Silicon-based(Si)materials are promising anodes for lithium-ion batteries(LIBs)because of their ultrahigh theoretical capacity of 4200 mA h g^(−1).However,commercial applications of Si anodes have been hindered by their drastic volume variation(∼300%)and low electrical conductivity.Here,to tackle the drawbacks,a hierarchical Si anode with double-layer coatings of a SiOx inner layer and a nitrogen(N),boron(B)co-doped carbon(C-NB)outer layer is elaborately designed by copyrolysis of Si-OH structures and a H3BO_(3)-doped polyaniline polymer on the Si surface.Compared with the pristine Si anodes(7mA h g^(−1) at 0.5 A g^(−1) after 340 cycles and 340 mA h g^(−1) at 5 A g^(−1)),the modified Si-based materials(Si@SiOx@C-NB nanospheres)present su perior cycling stability(reversible 1301 mA h g^(−1) at 0.5 A g^(−1) after 340 cycles)as well as excellent rate capability(690mA h g^(−1) at 5 A g^(−1))when used as anodes in LIBs.The unique double-layer coating structure,in which the inner amorphous SiOx layer acts as a buffer matrix and the outer defect-rich carbon enhances the electron diffusion of the whole anode,makes it possible to de liver excellent electrochemical properties.These results indicate that our double-layer coating strategy is a promising approach not only for the devel opment of sustainable Si anodes but also for the design of multielement-doped carbon nanomaterials.

Selective oxidation of biomass derived 5-hydroxymethylfurfural to 2,5-diformylfuran using sodium nitrite

A mild and simple process for the effective oxidation of 5-hydroxymethylfurfural（HMF） into 2,5-diformylfuran（DFF） has been developed using Na NO2 as the oxidant. Some important reaction parameters were investigated to optimize the oxidation of HMF into DFF. It was found that the reaction solvent was very crucial for this reaction. Trifluoroacetic acid was the best solvent for the oxidation of HMF into DFF by Na NO2.Under the optimal reaction condition, almost quantitative HMF conversion and high DFF yield of 90.4% were obtained after 1 h at room temperature.

Visible light-driven oxidant-free dehydrogenation of alcohols in water using porous ultrathin g-C_(3)N_(4)nanosheets

Graphitic carbon nitride(g-C_(3)N_(4)) is a fascinating photocatalyst for solar energy utilization in photo-catalysis.Nevertheless,it often suffers from moderate photo-catalytic activity due to its low specific surface area and fast recombination rate of photogenerated electrons upon photo-excitation.Herein,we overcome the bottlenecks by constructing a porous g-C_(3)N_(4) nanosheet(PCNS)through a simple thermal oxidation etching method.Benefited from its porous layer structure,the obtained PCNS exhibits large specific surface area,efficient separation of photogenerated charge carriers,as well as high exposure of active sites.As a result,it is robust and universal in visible light-driven dehydrogenation of alcohols in water under oxidant-free condition.Almost quantitative yields(>99%)of various valuable carbonyl compounds were obtained over PCNS,while bulk g-C_(3)N_(4) was far less efficient.Moreover,the photo-catalyst was highly stable and could be facilely recovered from the aqueous system for efficient reuse.The easy preparation and excellent performance made PCNS a promising and competitive photocatalyst for the solar applications.

Fabrication of a solid superacid with temperature-regulated silica-isolated biochar nanosheets

This paper reports a new strategy for the structural reconstruction of biomass carbon sulfonic acid(BCSA)to its solid superacid counterpart.In this approach,a cheap layered biomass carbon(BC)source is chemically exfoliated by cetyltrimethyl ammonium bromide and then converted to silica-isolated carbon nanosheets(CNSs)by a series of conversion steps.The state of the silica-isolated CNSs and the stacking density of their nanoparticles are regulated by the dehydration temperature.Only the highly isolated and non-crosslinked CNSs with loose particle stacking structures obtained upon dehydration at 250℃ can be turned into superacid sites(with stronger acidity than that of 100%H2 SO4)after sulfonation.This is accompanied by the creation of abundant hierarchical slit pores with high external surface area,mainly driven by the strong hydrogen bonding interactions between the introduced sulfonic acid groups.In typical acid-catalyzed esterification,etherification,and hydrolysis reactions,the newly formed superacid exhibits superior catalytic activity and stability compared to those of common BCSA and commercial Amberlyst-15 catalysts,owing to its good structural stability,highly exposed stable superacidic sites,and abundance of mesoporous/macroporous channels with excellent mass transfer rate.This groundbreaking work not only provides a novel strategy for fabricating bio-based solid superacids,but also overcomes the drawbacks of BCSA,i.e.,unsatisfactory structural stability,acidity,and porosity.

Comparative Study of Hypophosphite H2PO2^- Adsorption on Ni（111） and Ag（111） Surfaces by DFT

Surface structures and electronic properties of hypophosphite H2PO2^- on Ni（111） and Ag（111） surfaces were investigated by means of density functional theory at B3LYP/6-31 ＋ ＋G（d,p） level. The most stable structure was that in which the H2PO2^- adsorbs with its two P--O bonds faced to the substrate surface. The results of the Mulliken population analysis showed that because of the subtle difference of electron configuration, the adsorption energy was larger on the Ni surface than on the Ag surface, and the amounts of both donation and back donation were larger on the Ni（111） surface than on the Ag（111） surface. There were more negative Mulliken charge transfer from H2PO2^- to substrate clusters on Ni surface than on Ag surface and more positive Mulliken charges on P atom in Ni4H2PO2^- than in Ag4H2PO2^-, which means that P atom in Ni4H2PO2^- is easily attacked by a nucleophile such as OH . Thus, H2PO2^- is more easily oxidated on Ni（111） surface than on Ag（111） suface. These results indicated that the silver surface is inactive for the oxidation reaction of the hypophosphite anion.

Synthesis and Herbicidal Activity of Novel N-（2-Fluoro-5（3- methyl-2,6-dioxo-4-（trifluoromethyl）-2,3-dihydro-pyrimidin- l（6H）-yl）phenyl）-2-phenoxyacetamide Derivatives

Thirteen novel N-（2-fluoro-5-（3-methyl-2,6-dioxo-4-（trifluoromethy）-2,3-dihydropyrimidin-1（6H）-yl）phenyl）- 2-phenoxy）acetamides were designed and synthesized utilizing 4-fluoro-aniline and ethyl 3-amino-4,4,4-trifluoro-but-2-enoate as starting materials. The chemical structures of all compounds were confirmed by IH NMR, IR, mass spectrum and elemental analyses. Subsequently, the herbicidal activities of the as-prepared compounds were evalu-ated in the greenhouse. Bioassay results indicated that most of compounds had better herbicidal activities against dicotyledonous weeds. Among all the tested compounds, compounds 4a--4i showed good herbicidal activities at both pre-emergence and post-emergence treatment against two or three kinds of dicotyledonous weeds, such as Abutilon theophrasti Medic, Amaranthus ascendens L, and Chenopodium album L at the dosage of 75 g ai/ha.

Electrochemical quartz crystal microbalance study on the two-electrode-system cyclic voltammetric behavior of Prussian blue films

A two-channel electrochemical quartz crystal microbalance (EQCM) was used to investigate the cyclic voltammetric behavior of two Prussian blue (PB) film-modified Au electrodes in a two-electrode con-figuration in aqueous solution. The redox peaks observed in the two-electrode cyclic voltammogram (CV) are assigned to the intrinsic redox transitions among the Everitt's salt, PB, and Prussian yellow for the film itself, the redox process of the Au substrate and the redox process of small-quantity ferri-/ferrocyanide impurities entrapped in the PB film, as also supported by ultraviolet-visible (UV-Vis) spectroelectrochemical data. The profile of the two-electrode solid-state CV for the PB powder sand-wiched between two gold-coated indium-tin oxide (ITO) electrodes is similar to that for two PB-modified Au electrodes in aqueous solution, implying similar origins for the corresponding redox peaks. The two-channel EQCM method is expected to become a highly effective technique for the studies of the two-electrode electrochemical behaviors of many other species/materials.

A piezoelectric spectro- electrochemical study on the structural interconversion for poly(o-phenylenediamine) between its ladder structure with phenazine units and polyaniline-like chains

The combination of reflectance UV-Vis spec- troelectrochemistry with electrochemical quartz crystal microbalance (EQCM) and separate reflectance FTIR char- acterization were used to investigate the structural intercon- version for poly(o-phenylenediamine) (PoPD) between its ladder structure with phenazine units and polyaniline-like linear chains. The poly(o-phenylenediamine) films potentio- statically (0.8 V vs. SCE) grew on Au electrodes from 0.20 mol·L?1 H2SO4 (PoPD1) or 0.40 mol·L?1 NaOH (PoPD2) aque- ous solution containing 0.20 mol·L?1 Na2SO4 + 0.10 mol·L?1 o-phenylenediamine. By considering the mass of deposited PoPD2 film obtained from the EQCM data and the charge consumed under the current peak at ca. 0.6 V vs. SCE for oxidation of -NH2 groups in as-prepared PoPD2 during po- tential cycling in 0.10 mol·L-1 aqueous H2SO4, the molar per- centage of the polyaniline-like chains was estimated to be 19% (relative to total phenylenediamine units), being in agreement with the result obtained from a formaldehyde- combination experiment through the aminocarbonyl reaction. After 40-cycle potential sweeps between 0.2 and 0.8 V vs. SCE the polyaniline-like chains in PoPD2 could be com- pletely converted via intramolecular cyclization into the lad- der structure with phenazine units. However, PoPD1 was found to be perfectly composed of the ladder structure with phenazine units, and after 40-cycle potential sweeps between ?0.4 and 0.1 V vs. SCE only 2.5% in molar percentage of PoPD’s ladder structure could be converted into polyani line-like chains, suggesting that the ladder structure with phenazine units is thermodynamically more stable due to its possessing higher conjugation.

A multisite-binding fluorescent probe for simultaneous monitoring of mitochondrial homocysteine, cysteine and glutathione in live cells and zebrafish

Homocysteine(Hcy), cysteine(Cys) and glutathione(GSH) play crucial roles in redox homeostasis during mitochondria functions. Simultaneous differentiation and visualization of mitochondrial biothiols dynamics are significant for understanding cell metabolism and their related diseases. Herein, a multisitebinding fluorescent probe(MCP) was developed for simultaneous sensing of mitochondrial Cys, GSH and Hcy from three fluorescence channels for the first time. This novel probe exhibited rapid fluorescence turn-on, good water-solubility, high selectivity and large spectral separation for discriminating Cys, GSH and Hcy with 131-, 96-, 748-fold fluorescence increasement at 471, 520, 567 nm through different excitation wavelengths, respectively. Importantly, this probe was successfully applied to simultaneous monitoring of mitochondrial Cys, GSH, and Hcy in live cells and zebrafish from three fluorescence channels,promoting the understanding of the functions of Hcy, Cys and GSH.

Electrochemical quartz crystal microbalance study on Au-supported Pt adlayers for electrocatalytic oxidation of methanol in alkaline solution

Underpotential deposition(UPD) of Cu on an Au electrode followed by redox replacement reaction(RRR) of CuUPD with a Pt source(H2PtCl6 or K2PtCl4) yielded Au-supported Pt adlayers(for short,Pt(CuUPD-Pt4+)n/Au for H2PtCl6,or Pt(CuUPD-Pt2+)n/Au for K2PtCl4,where n denotes the number of UPD-redox replacement cycles).The electrochemical quartz crystal microbalance(EQCM) technique was used for the first time to quantitatively study the fabricated electrodes and estimate their mass-normalized specific electrocatalytic activity(SECA) for methanol oxidation in alkaline solution.In comparison with Pt(CuUPD-Pt2+)n/Au,Pt(CuUPD-Pt4+)n/Au exhibited a higher electrocatalytic activity,and the maximum SECA was obtained to be as high as 35.7 mA ?g?1 at Pt(CuUPD-Pt4+)3/Au.The layer-by-layer architecture of Pt atoms on Au is briefly discussed based on the EQCM-revealed redox replacement efficiency,and the calculated distribution percentages of bare Au sites agree with the experimental results deduced from the charge under the AuOx-reduction peaks.The EQCM is highly recommended as an efficient technique to quantitatively examine various electrode-supported catalyst adlayers,and the highly efficient catalyst adlayers of noble metals are promising in electrocatalysis relevant to biological,energy and environmental sciences and technologies.

Palladium-catalyzed cascade synthesis of spirocyclic oxindoles via regioselective C2-H arylation and C8-H alkylation of naphthalene ring

A simultaneous C2-H arylation and C8-H alkylation of naphthalene ring has been achieved by palladiumcatalyzed cascade reaction of N-(2-halophenyl)-2-(naphthalen-1-yl)acrylamides with aryl iodides,which provides an efficient method for synthesizing various aryl-substituted spirocyclic oxindoles.The protocol enables three C-C bonds formation via an intramolecular Heck reaction and sequentially regioselective C-H bond activation.

Synthesis and cytotoxic activity of 3-phenyl-4-substituted-β-carbolines

A new class of 3-phenyl-4-substituted-β-carbolines via iodine-mediated electrophilic cyclization as key step were synthesized and their inhibitory activity against three tumor cell lines was evaluated in vitro. It was found that some of the tested compounds showed better cytotoxicity against HeLa and MCF-7 cells than harmine.

Copper-catalyzed three-component reaction of imidazo[1,2-a]pyridine with elemental sulfur and arylboronic acid to produce sulfenylimidazo[1,2-a]pyridines

In this work, an efficient copper-catalyzed three-component reaction for the synthesis of sulfenylimidazo [1,2-a]pyridines using elemental sulfur as the sulfenylating agents has been developed. The reaction could proceed smoothly with a high degree of functional group tolerance and provide the desired products in moderate to good yield.

Simple Enzyme-Free Biosensor for Highly Sensitive and Selective Detection of miR-21 Based on Multiple Signal Amplification Strategy

Due to the fact that most microRNAs are small in size,low abundance in biological samples,homologous sequence among family members,and protein enzymes-based strategies display limited practical applications,therefore,we reported a simple enzyme-free DNA sensor for microRNA detection utilizing a multiple signal amplification strategy.The sensing system termed as C-CHA-HCR includes six hairpin DNA reactants that are metastable on account of intramolecular hybridization.The DNA hairpin reactants are opened and hybridized with the corresponding complementary DNA strand in the presence of miR-21 via toehold-mediated CHA,HCR reaction,and circulation between CHA and HCR,resulting in a hugely amplifying signal output.Without introducing external protein enzymes,this sensing system showed highly sensitive and selective on the detection of miR-21.A linear response range of miR-21 from 25 pmol/L to 1 nmol/L with a limit of detection(LOD)of 1.8 pmol/L was obtained.This promising biosensor was successfully applied to the detection of microRNA in human serum samples with acceptable recovery rates,suggesting the potential applications in disease diagnosis,treatment,and prognosis.

Ce^(3+),Cr^(3+)co-doped garnet phosphors with yellow and near-infrared emission for white and near-IR dual-mode pc-LEDs

Cr^(3+)-activated phosphors with adjustable near-infrared(NIR)emission have attracted considerable attention due to their diverse applications across various fields.While modifying the emission wavelength of Cr^(3+)can be achieved by adjusting its coordination environment,the parity-forbidden d-d transition presents a challenge by limiting absorption and resulting in a low external quantum efficiency(EQE)in Cr^(3+)-doped phosphors.Moreover,longer emission wavelengths often coincide with reduced thermal stability.To address these issues,energy transfer from a sensitizer to Cr^(3+)has been proposed as a strategy to enhance both EQE and thermal stability of NIR emission.The selection of an appropriate host structure is crucial.In this study,a garnet structure,Ca_(2)LuMgScSi_(3)O_(12),was identified as a promising candidate for achieving efficient broadband NIR emission under blue light excitation.Specifically,Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+)exhibited a yellow emission with exceptional internal quantum efficiency and EQE of up to 94.6%and 64.8%,respectively.By leveraging efficient energy transfer from Ce^(3+)to Cr^(3+),the Ca_(2)LuMgScSi_(3)-O_(12):Ce^(3+),Cr^(3+)phosphors exhibited tunable yellow to NIR emission.Notable,the highest EQE recorded for Ca_(2)LuMgScSi_(3)O_(12):Ce^(3+),Cr^(3+)was 56.9%,significantly surpassing that of the Cr^(3+)single-doped counterpart.Furthermore,the co-doped phosphor demonstrated thermal stability comparable to that of Ce^(3+)single-doped phosphor.Of particular significance,the developed prototype pc-LED emitted a combination of broadband white and NIR light,demonstrating potential applications in solar-like lighting,food analysis,and biomedical imaging.

Artificial Nucleic Acid Tractor-Directed Simultaneous Depletion of Oncogenic Membrane Proteins Without Hijacking Proteolysis-Specific Actuator

Targeted protein degradation(TPD)is an emerging tool for degrading proteins of interest,which affords an attractive modality for cancer therapy.However,the present TPD technologies must engage a proteolysis-specific actuator to initiate degradation of targeted proteins in the proteasome or lysosome.Herein,we report an artificial tractor that can induce endocytosis-mediated protein depletion without hijacking a proteolysis-specific actuator.In this design,bispecific aptamer chimeras(BSACs)are established,which can bridge human epidermal growth factor receptor 2(ErbB-2),an important biomarker in a common important biomarker in cancer,with membrane proteins of interest.Taking advantage of the property of aptamer-induced endocytosis and digestion of ErbB-2,another membrane protein is translocated into the lysosome in a hitchhike-like manner,resulting in lysosomal proteolysis along with ErbB-2.This strategy frees the TPD from the fundamental limitation of proteolysis-specific actuator and allows simultaneous regulation of the quantity and function of two oncogenic receptors in a cell-type-specific manner,expanding the application scope of TPD-based therapeutics.

Blinking CsPbBr_(3) perovskite nanocrystals for the nanoscopic imaging of electrospun nanofibers

Blinking fluorophore perovskite nanocrystals (NCs) were employed to image the fine structure of the polystyrene (PS) electrospun fibers. The conditions of CsPbBr3 NCs embedded and dispersed into PS were investigated and optimized. The stochastic optical reconstruction microscopy is employed to visualize the fine structure of the resulted CsPbBr3@PS electrospun fibers at sub-diffraction limit. The determined resolution in the reconstructed nanoscopic image is around 25.5 nm, which is much narrower than that of conventional fluorescence image. The complex reticulation and multicompartment in bead sub-diffraction-limited structures of CsPbBr3@PS electrospun fibers were successfully mapped with the help of the stochastic blinking properties of CsPbBr3 NCs. This work demonstrated the potential applications of CsPbBr3 perovskite NCs in super-resolution fluorescence imaging to reconstruct the sub-diffraction-limited features of polymeric material.

Ionic Liquid-assisted Formation of Lanthanide Metal-organic Framework Nano/Microrods for Superefficient Removal of Congo Red

New lanthanide metal-organic framework（MOF） nano/microrods, [C4mim]Cl-Eu-MOF, [C8mim]Cl-Eu- MOF and [C12mim]Cl-Eu-MOF, were conveniently synthesized via an ionic liquid-assisted hydrothermal method and characterized by means of powder X-ray diffraction（XRD）, Fourier transform infrared spectroscopy（FTIR）, thermo- gravimetric analysis（TG） and transmission electron microscopy（TEM）. The obtained nano/microrods with low sur- face areas were efficient for the removal of Congo red（CR） from aqueous solutions. Under the optimum conditions, [C4mim]Cl-Eu-MOF with a specific surface area of 5.1 m^2/g exhibited an ultrahigh adsorption capacity of 2606 mg/g toward CR. Notably, the adsorption efficiency of [C4mim]Cl-Eu-MOF for CR via nano/microscale stacking can be directly demonstrated by TEM. In-depth understanding of CR removal by [C4mim]Cl-Eu-MOF nano/microrods was also supported by FTIR, Raman spectroscopy and zeta potential analyses.