Synthesis and antimicrobial activity of novel chalcone derivatives

A series of novel 3-[N, N-bis(2-hydroxyethyl)-amino]-chalcone derivatives 3a–3j were synthesized by the aldol condensation of [N, N-bis(2-hydroethyl)-3-amino]-acetophenone 2 with aromatic aldehydes. Their structures were further confirmed by ESI-HRMS, ¹H NMR, IR and elemental analysis. X-ray analysis reveals crystal 3b is a monoclinic system with P2₁/n space group. The antimicrobial activities of the newly synthesized chalcones in vitro were evaluated and the results indicated that most compounds presented moderate to good antimicrobial activities, especially the antifungal capability. Compounds 3a, 3d, 3f and 3g revealed obvious potency against Candida albicans with MIC values of 32 μg/mL, which were better compared with others.     

Mechanism for nucleation and growth of electrochemical deposition of palladium(II) on a platinum electrode in hydrochloric acid solution

Palladium(II)and chloride ions tend to form complexes in aqueous solution.Both theoretical and experimental(by UV spectrum)results indicate that there are four complexes formed in aqueous solution containing 3 mol/L hydrochloric acid and 20mmol/L PdCl2.This work evaluates the kinetics of electrochemical deposition of palladium on a Platinum electrode.For this purpose,palladium electrodeposition was investigated by means of cyclic voltammetry(CV),potentiostatic current-time transients(CTTs)and Tafel curve.By CTTs curves,the regions corresponding to the charge transfer control,mixed control and diffusion control were identified.In the diffusion control region,palladium electrodeposition mechanism was characterized as progressive nucleation with three-dimensional(3D)growth under diffusion control;as for the mixed control region,an adsorption(IAds),ion transfer(IIT),and nucleation and growth(ING)model were proposed to analyze the current-time transients quantitatively,which could separate the IAds,IIT and ING perfectly.     

Sequential Hydroformylation/Diels–Alder Processes: One‐Pot Synthesis of Polysubstituted Cyclohexenes,Cyclohexadienes, and Phthalates from Alkynes

A novel, one‐pot hydroformylation/Diels–Alder sequence for the synthesis of multisubstituted cyclohexenes, cyclohexadienes, and phthalates has been developed. Various alkynes were efficiently converted into the corresponding products in good yields and with excellent diastereoselectivity through palladium‐catalyzed hydroformylation followed by an AAD‐type reaction (AAD: Amides–Aldehydes–Dienophiles). In view of the availability of the substrates, the atom‐efficiency of the overall process, and the convenient introduction of substituents in the cyclohexene ring, this method complements current methods for the preparation of polysubstituted cyclohexane derivatives.     

Visualization and In Situ Ablation of Intracellular Bacterial Pathogens through Metabolic Labeling

Protected by the host cells, the hidden intracellular bacteria are typically difficult to kill by common antibiotics and cannot be visualized without complex cellular pretreatments. Herein, we successfully developed a bacteria‐metabolizable dual‐functional probe TPEPy‐d ‐Ala, which is based on d ‐alanine and a photosensitizer with aggregation‐induced emission for fluorescence turn‐on imaging of intracellular bacteria in living host cells and photodynamic ablation in situ. Once metabolically incorporated into bacterial peptidoglycan, the intramolecular motions of TPEPy‐d ‐Ala are inhibited, leading to an enhanced fluorescent signal, which allows the clear visualization of the intracellular bacteria. Moreover, TPEPy‐d ‐Ala can effectively ablate the labeled intracellular bacteria in situ owing to covalent ligation to peptidoglycan, yielding a low intracellular minimum inhibitory concentration (MIC) of 20±0.5 μg mL^?1, much more efficient than that of a commonly used antibiotic, vancomycin.     

Quantitative Design of Bright Fluorophores and AIEgens by the Accurate Prediction of Twisted Intramolecular Charge Transfer (TICT)

Inhibition of TICT can significantly increase the brightness of fluorescent materials. Accurate prediction of TICT is thus critical for the quantitative design of high‐performance fluorophores and AIEgens. TICT of 14 types of popular organic fluorophores were modeled with time‐dependent density functional theory (TD‐DFT). A reliable and generalizable computational approach for modeling TICT formations was established. To demonstrate the prediction power of our approach, we quantitatively designed a boron dipyrromethene (BODIPY)‐based AIEgen which exhibits (almost) barrierless TICT rotations in monomers. Subsequent experiments validated our molecular design and showed that the aggregation of this compound turns on bright emissions with ca. 27‐fold fluorescence enhancement, as TICT formation is inhibited in molecular aggregates.     

Rational Design of a Two‐Photon Fluorogenic Probe for Visualizing Monoamine Oxidase A Activity in Human Glioma Tissues

Monoamine oxidases have two functionally distinct but structurally similar isoforms (MAO‐A and MAO‐B). The ability to differentiate them by using fluorescence detection/imaging technology is of significant biological relevance, but highly challenging with available chemical tools. Herein, we report the first MAO‐A‐specific two‐photon fluorogenic probe ( F1 ), capable of selective imaging of endogenous MAO‐A enzymatic activities from a variety of biological samples, including MAO‐A‐expressing neuronal SY‐SY5Y cells, the brain of tumor‐bearing mice and human Glioma tissues by using two‐photon fluorescence microscopy (TPFM) with minimal cytotoxicity.     

Systematic Research and Evaluation Models of Nanomotors for Cancer Combined Therapy

Limited tumor permeability of therapeutic agents is a great challenge faced by current cancer therapy methods. Herein, a kind of near infrared light (NIR)‐driven nanomotor with autonomous movement, targeted ability, hierarchical porous structure, multi‐drugs for cancer chemo/photothermal therapy is designed, prepared and characterized. Further, we establish a method to study the interaction between nanomotors and cells, along with their tumor permeability mechanism, including 2D cellular models, 3D multicellular tumor spheroids and in vivo models. In vivo tumor elimination results verify that the movement behaviour of the nanomotors can greatly facilitate them to eliminate tumor through multiple therapeutic methods. This work tries to establish systematic research and evaluation models, providing strategies to understand the relationship between motion behaviour and tumor permeation efficiency of nanomotors in depth.     

Pebax‐Based Membrane Filled with Two‐Dimensional Mxene Nanosheets for Efficient CO2 Capture

Mixed matrix membranes (MMMs) made from inorganic fillers and polymers is a kind of promising candidate for gas separation. In this work, two‐dimensional MXene nanosheets were synthesized and incorporated into a polyether‐polyamide block copolymer (Pebax) matrix to fabricate MMM for CO₂ capture. The physicochemical properties of MXene nanosheets and MXene/Pebax membranes were studied systematically. The introduction of MXene nanosheets provided additional molecular transport channels and meanwhile enhanced the CO₂ adsorption capacity, thereby enhancing both the CO₂ peremance and CO₂/N₂ selectivity of Pebax membrane. The optimized MXene/Pebax membrane with a MXene loading of 0.15 wt % displayed a high separation performance with a CO₂ permeance of 21.6 GPU and a CO₂/N₂ selectivity of 72.5, showing potential application in CO₂ capture.     

2020 Roadmap on Carbon Materials for Energy Storage and Conversion

Carbon is a simple, stable and popular element with many allotropes. The carbon family members include carbon dots, carbon nanotubes, carbon fibers, graphene, graphite, graphdiyne and hard carbon, etc. They can be divided into different dimensions, and their structures can be open and porous. Moreover, it is very interesting to dope them with other elements (metal or non‐metal) or hybridize them with other materials to form composites. The elemental and structural characteristics offer us to explore their applications in energy, environment, bioscience, medicine, electronics and others. Among them, energy storage and conversion are extremely attractive, as advances in this area may improve our life quality and environment. Some energy devices will be included herein, such as lithium‐ion batteries, lithium sulfur batteries, sodium‐ion batteries, potassium‐ion batteries, dual ion batteries, electrochemical capacitors, and others. Additionally, carbon‐based electrocatalysts are also studied in hydrogen evolution reaction and carbon dioxide reduction reaction. However, there are still many challenges in the design and preparation of electrode and electrocatalytic materials. The research related to carbon materials for energy storage and conversion is extremely active, and this has motivated us to contribute with a roadmap on ‘Carbon Materials in Energy Storage and Conversion’.     

Gd0.2Ce0.8O1.9纳米颗粒对固体氧化物电解池La0.6Sr0.4Co0.2Fe0.8O3-δ阳极 析氧反应的影响

化石燃料的使用排放了大量CO2,对气候和环境造成了日益严重的危害.固体氧化物电解池(SOEC)能够利用可再生能源产生的电能将CO2高效转化成CO,降低CO2排放的同时,又能减少化石燃料的使用,近年来受到研究者的广泛关注.相比于低温液相CO2电还原,SOEC高的运行温度保证了其较高的反应速率,即较高的电流密度.典型的SOEC单电池由多孔阴极、致密电解质和多孔阳极以三明治的方式组装而成.CO2分子在阴极得到两个电子解离成CO和一个O2–;生成的O2–通过致密电解质传导至阳极,在阳极失去四个电子发生析氧反应(OER)生成一个O2.相比于两电子的阴极反应,阳极四电子的析氧反应更难进行,可能是整个电极过程的速控步,因此开发高性能的阳极材料有望显著提高SOEC的CO2电还原性能.La0.6Sr0.4Co0.2Fe0.8O3-δ(LSCF)因具有较高的混合离子-电子导电性而被用作SOEC阳极材料,但受LSCF-气体两相界面的限制,其OER性能较低.研究表明,LSCF-掺杂的CeO2-气体所构成的三相界面相比于LSCF-气体两相界面具有更高的电化学反应活性,即OER反应更易在三相界面进行.因此,本文将Gd0.2Ce0.8O1.9(GDC)纳米颗粒浸渍到SOEC LSCF阳极来提高其OER活性,考察了纳米颗粒浸渍量(3,5,10和20 wt%)对SOEC电化学性能的影响.结果表明,SOEC的电化学性能随浸渍量的增加而逐渐升高,当GDC纳米颗粒浸渍量为10 wt%时(10GDC/LSCF),SOEC的电化学性能达到最高,在800 oC和1.6 V的电流密度为0.555 A cm–2,是LSCF阳极SOEC性能的1.32倍.继续增加浸渍量到20 wt%,电化学性能反而开始下降.电化学阻抗谱测试结果表明,GDC纳米颗粒的加入减小了SOEC的极化电阻.对应的弛豫时间分布函数解析结果表明10GDC/LSCF阳极上的OER由四个基元反应构成.电镜和O2-程序升温脱附结果表明,GDC纳米颗粒的加入显著增加了10GDC/LSCF阳极三相界面和表面氧空位的数量以及体相氧的流动性,从而促进了OER四个基元反应的反应速率,降低了这几个过程的极化电阻,因而降低了OER反应的极化电阻,提高了SOEC电还原CO2的电化学性能.