Asymmetric Synthesis of Anti-tuberculosis-specific Drug TBAJ-876 through Synergistic Li/Li Catalysis

TBAJ-876, developed by TB Alliance, a novel anti-tuberculosis-specific drug, has entered Phase II clinical trials. Herein, the first asymmetric synthesis of TBAJ-876 has been realized using synergistic Li/Li catalysis with excellent yield of 95% and 88 : 12 er (99.6 : 0.4 er, 10 : 1 dr after simple recrystallization). Furthermore, DFT calculations and 7Li-NMR analysis illustrated the mechanism of the synergistic reaction: a chiral Li-complex activates the nucleophile to control the stereoselectivity, while the other achiral Li-complex activates the electrophile to catalyze the carbonyl addition reaction. Additionally, this protocol has been successfully carried out at 5 gram-scale, showing its industrial potential.

Construction of Synergistic Co and Cu Diatomic Sites for Enhanced Higher Alcohol Synthesis

Higher alcohol synthesis(HAS)from syngas could efficiently alleviate the dependence on the traditional fossil resources.However,it is still challenging to construct high-performance HAS catalysts with satisfying selectivity,space–time yield(STY),and stability.Herein,we designed a diatomic catalyst by anchoring Co and Cu sites onto a hierarchical porous N-doped carbon matrix(Co/Cu–N–C).The Co/Cu–N–C is efficient for HAS and is among the best catalysts reported.With a COconversion of 81.7%,C2+OHselectivity could reach 58.5%with an outstanding C2+OH STY of 851.8 mg/g·h.We found that the N4–Co1 and Cu1–N4 showed an excellent synergistic effect.The adsorption of CO occurred on the Co site,and the surrounding nitrogen sites served as a hydrogen reservoir for the CO reduction reactions to form CHxCo.Meanwhile,the Cu sites stabilized a CHOCu species to interact with CHxCo,facilitating a barrier-free formation of C2 species,which is responsible for the high selectivity of higher alcohols.

Amide Ionic Liquids(AILs)/L-Proline Synergistic Catalyzed Asymmetric Mannich Reactions

Amide ionic liquids （MLs）/L-proline synergistic catalyzed Mannich reactions of isovaleraldehyde, methyl ketones, and aromatic amines were carried out in moderate to high yields （ up to 96% ） and high stereo selectivities （ 〉99% e. e. ）. The products were easily isolated by extraction; and the catalyst system was readily recycled at least thrice without significant loss of efficiency. The scope of the substrates was studied and the interpretation of the manifest improvement of the reaction rates and enantio-selectivity of the novel catalyst system was speculated.

Fischer–Tropsch synthesis over iron catalysts with corncob-derived promoters

A sustainable strategy for Fischer–Tropsch iron catalysts is successfully achieved by embedding of synergistic promoters from a renewable resource, corncob. The iron-based catalysts, named as 'corncob-driven'catalysts, are composed of iron species supported on carbon as primary active components and various minerals(K, Mg, Ca, and Si, etc.) as promoters. The corncob-driven catalysts are facilely synthesized by a one-pot hydrothermal treatment under mild conditions. The characterization results indicate that the formation of iron carbides from humboldtine is clearly enhanced and the morphology of catalyst particles tends to be more regular microspheres after adding corncob. It is observed that the optimized corncob-driven catalyst exhibits a higher conversion than without promoters' catalyst in Fischer–Tropsch synthesis(ca. 73% vs. ca. 49%). More importantly, a synergistic effect exists in multiple promoters from corncob that can enhance heavy hydrocarbons selectivity and lower CO_2 selectivity, obviously different from the catalyst with promoters from chemicals. The proposed synthesis route of corncob-driven catalysts provides new strategies for the utilization of renewable resources and elimination of environmental pollutants from chemical promoters.

Green rapid synthesis of Cu_(2)O/Ag heterojunctions exerting synergistic antibiosis

Semiconductor-noble metal composite has become a research focus due to its superior performance compared with its respective component.Although various methods have been developed to synthesize semiconductor-noble metal heterostructures,most of them are relatively complex multistep and use toxic reactants of high cost and risk.In this work,a series of Cu_(2)O/Ag heterojunctions were quickly prepared in one step via simple microwave-assisted green route.XRD,SEM,TEM,EDS,XPS,etc.were used to characterize obtained products,and the results indicate a Cu_(2)O/Ag metal-semiconductor heterojunction in micro-nano size was fabricated successfully.In addition,antibacterial behavior of Cu_(2)O/Ag heterojunctions against E.coli and S.aureus were investigated.Owing to the synergistic effect of Cu_(2)O and Ag,the heterojunction exhibits much better antibacterial performance than the pristine Cu_(2)O does.This work provides new insights into the green design and fabrication of surface-modified Cu_(2)O hybrid multifunctional materials for antibacterial applications.

Realization of high-purity 1T-MoS_(2)by hydrothermal synthesis through synergistic effect of nitric acid and ethanol for supercapacitors

Phase engineering of molybdenum disulfide(MoS_(2))can achieve phase transformation from the semiconducting phase(2H-MoS_(2))with poor conductivity to the metallic phase(1T-MoS_(2))with superior electrochemical properties.Therefore,it is desirable to prepare high concentration 1T-MoS_(2)by simple and facile methods.In this work,MoS_(2)with high concentration of 1T phase is successfully prepared by one-pot hydrothermal synthesis through the synergistic effect of HNO_(3)and CH_(3)CH_(2)OH,which is stable for more than half of a year.The as-synthesized MoS_(2)shows high capacitance of 392Fg^(-1)at 1A g^(-1)as used for supercapacitors electrodes,and displays excellent capacitance retention(83%after 10,000 cycles).Asymmetric supercapacitors(ASCs)devices assembled by the as-synthesized MoS_(2)and MnO_(2)on carbon cloths,exhibit high energy and power densities(0.194 m Wh cm^(-2)and 13.466 mW cm^(-2)).These results shed a light to realize 1T phase MoS_(2)through the synergistic effect in hydrothermal processing.

Synergistic Copper and Chiral Lewis Base Catalysis for the Asymmetric Synthesis of Pyrrolo[1,2-a]indoles

The first asymmetric decarboxylative[3+2]-cycloaddition of ethynyl indoloxazolidones with carboxylic acids has been developed under synergistic catalysis of copper and chiral Lewis base.This protocol provides a direct and modular approach to biologically important pyrrolo[1,2-a]indoles bearing two vicinal stereogenic centers with excellent diastereo-and enantioselectivities(up to>20:1 dr and>99%ee).In addition,the utility of this methodology was demonstrated by scaled-up reaction and several synthetic transformations of the cycloadduct.

Stereodivergent synthesis ofα-fluoroα-azaarylγ-butyrolactones via cooperative copper and iridium catalysis

The development of stereodivergent synthetic methods to access all four stereoisomers of biologically importantα-fluoroγ-butyrolactones containing vicinal stereocenters is of great importance and poses a formidable challenge owing to ring strain and steric hindrance.Herein,a novel asymmetric[3+2]annulation ofα-fluoroα-azaaryl acetates with vinylethylene carbonate was successfully developed through Cu/Ir-catalyzed cascade allylic alkylation/lactonization,affording a variety of enantioenrichedα-fluoroγ-butyrolactones bearing vicinal stereogenic centers with high reaction efficiency and excellent levels of both stereoselectivity and regioselectivity(up to 98%yield,generally>20:1 dr and>99%ee).Notably,all four stereoisomers of these pharmaceutically valuable molecules could be accessed individually via simple permutations of two enantiomeric catalysts.In addition,other azaaryl acetates bearingα-methyl,α-chlorine orα-phenyl group were tolerated well in this transformation.Reaction mechanistic investigations were conducted to explore the process of this bimetallic catalysis based on the results of reaction intermediates,isotopic labelling experiments,and kinetic studies.

Synergistic effect of Co and Co_(6)Mo_(6)C for electroreduction of nitrate to ammonia on Co-MOF derived Co_(6)Mo_(6)C/Co/NC

Electrocatalytic nitrate reduction reaction(e-NO_(3)RR)offers a promising alternative method for nitrogen cycling and ammonia(NH3)production under ambient conditions.However,the method is still in the dilemma of lowering the reaction overpotential and increasing the reaction activity.We successfully developed the composition-adjustable Co_(6)Mo_(6)C/Co/N-doped carbon(NC)catalysts by in situ carbonization of Co-based metal-organic framework(MOF)with the constrained phosphomolybdic acid.After adjusting the ratio of Co0 and Co_(6)Mo_(6)C,Co_(6)Mo_(6)C/Co/NC-3 could satisfy both NO_(3)−conversion at low potential and NH_(x)hydrogenation,and synthesize ammonia efficiently through the synergistic effect of Co0 and Co_(6)Mo_(6)C.It achieved an ammonia yield rate as 1233.2μg·h^(−1)·mgcat^(−1)and Faradaic efficiency of NH4+93.6%at−0.33 V vs.reversible hydrogen electrode(RHE).Importantly,density functional theory(DFT)calculations and experimental results have demonstrated for the first time the excellent adsorption of nitrite(NO_(2)^(−))by the Mo sites of Co_(6)Mo_(6)C during e-NO_(3)RR,avoiding the undesirable accumulation of NO_(2)^(−).

Diatomic Pd catalyst with conjugated backbone for synergistic electrochemical CO_(2)reduction

Double-site catalysts have attracted widespread attention in the field of electrocatalysis due to their high metal loading,adjustable active centres,and electronic valence states.However,the development of bimetallic sites catalysts that coordinate with definite atoms is still in the exploratory stage.Here,we designed and synthesized a bimetallic palladium complex(BPB-Pd_(2))with conjugated backbone.The supported BPB-Pd_(2)was applied to electrochemical CO_(2)reduction reaction(CO_(2)RR)for the first time.The as-obtained BPB-Pd_(2)gives an exceptional Faradaic efficiency of CO(FECO)of 94.4%at−0.80 V vs.reversible hydrogen electrode(RHE),which is significantly superior to monoatomic palladium catalyst(BPB-Pd1).The density functional theory(DFT)calculations revealed that the essential reason for the outstanding activity of BPB-Pd_(2)toward CO_(2)RR was that the electronic effect between diatomic palladium reduces the free energy change for CO_(2)RR process.Thus,BPB-Pd_(2)exhibits moderate free energy change to form COOH*intermediate,which was beneficial for the generation of CO in CO_(2)RR.

TabHLH95-TaNF-YB1 module promotes grain starch synthesis in bread wheat

Starch is the most abundant substance in wheat(Triticum aestivum L.)endosperm and provides the major carbohydrate energy for human daily life.Starch synthesis-related(SSR)genes are believed to be spatiotemporally specific,but their transcriptional regulation remains unclear in wheat.Here,we investigate the role of the basic helix-loop-helix(bHLH)transcription factor TabHLH95 in starch synthesis.TabHLH95 is preferentially expressed in the developing grains in wheat and encodes a nucleus localized protein without autoactivation activity.The Tabhlh95 knockout mutants display smaller grain size and less starch content than wild type,whereas overexpression of TabHLH95 enhances starch accumulation and significantly improves thousand grain weight.Transcriptome analysis reveals that the expression of multiple SSR genes is significantly reduced in the Tabhlh95 mutants.TabHLH95 binds to the promoters of ADP-glucose pyrophosphorylase large subunit 1(AGPL1-1D/-1B),AGPL2-5D,and isoamylase(ISA1-7D)and enhances their transcription.Intriguingly,TabHLH95 interacts with the nuclear factor Y(NF-Y)family transcription factor TaNF-YB1,thereby synergistically regulating starch synthesis.These results suggest that the TabHLH95-TaNF-YB1 complex positively modulates starch synthesis and grain weight by regulating the expression of a subset of SSR genes,thus providing a good potential approach for genetic improvement of grain productivity in wheat.

One-step synthesis and electromagnetic absorption properties of high entropy rare earth hexaborides(HE REB6)and high entropy rare earth hexaborides/borates(HE REB6/HE REB03)composite powders

Considering the emergence of severe electromagnetic interference problems,it is vital to develop electromagnetic(EM)wave absorbing materials with high dielectric,magnetic loss and optimized impedance matching.However,realizing the synergistic dielectric and magnetic losses in a single phase material is still a challenge.Herein,high entropy(HE)rare earth hexaborides(REB6)powders with coupling of dielectric and magnetic losses were designed and successfully synthesized through a facial one-step boron carbide reduction method,and the effects of high entropy borates intermedia phases on the EM wave absorption properties were investigated.Five HE REB6 ceramics including(Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6,(Ce0.2Hu0.2Sm0.2Er0.2Yb0.2)B6,(Ce0.2Y0.2Eu0.2Er0.2Yb0.2)B6,(Ce0.2Ya2Sm0.2Eu0.2Yb0.2)B6,and(Nd0.2Y0.2Sm0.2Eu0.2Yb0.2)B6 possess CsCl-type cubic crystal structure,and their theoretical densities range from 4.84 to 5.25 g/cm^(3).(Ce02Y0.2Sm0.2Er0.2Yb02)B6 powders with the average particle size of 1.86 jim were found to possess the best EM wave absorption properties among these hexaborides.The RLmin value of(Ce0.2Y0.2Sm0.2Er0.2Yb0.2)B6 reaches-33.4 dB at 11.5 GHz at thickness of 2 mm;meanwhile,the optimized effective absorption bandwidth(EAB)is 3.9 GHz from 13.6 to 17.5 GHz with a thickness of 1.5 mm.The introduction of HE REB03(RE=Ce,Y,Sm,Eu,Er,Yb)as intermediate phase will give rise to the mismatching impedance,which will further lead to the reduction of reflection loss.Intriguingly,the HEREB6/HEREB03 still possess wide effective absorption bandwidth of 4.1 GHz with the relative low thickness of 1.7 mm.Considering the better stability,low density,and good EM wave absorption properties,HE REB6 ceramics are promising as a new type of EM wave absorbing materials.

Synergistic Catalysis with Azomethine Ylides

Azomethine ylides are useful intermediates for the rapid construction of chiral N-containing compounds.However,its synthetic potential has not been fully developed due to the limited reaction models.In combination with synergistic catalysis and azomethine ylide chemistry,we have developed several types of novel catalytic system including Cu/Pd,Cu/Ir and PTC/Ir catalysis;which can convert readily-available azomethine ylides to various high-valued molecules such as unnatural a-amino acids,homoallylic amines and N-heterocycles.Compared with the traditional mono-catalysis,the synergistic catalyst system exhibits enhanced catalytic efficiency and chiral induction ability in many cases.In addition,we have demonstrated that these strategies could be applied in the construction of bioactive compounds and natural products.

CdS/石墨烯纳米复合光催化剂的可控合成及其性能研究

光催化技术是一种在能源和环境领域有着重要应用前景的绿色技术。为提高光催化效率,利用简单的“自下而上”法合成了尺寸可控,具有中空内核且核与壳之间有一定间隙层的中空蛋黄壳结构型CdS/石墨烯复合光催化剂Hollow CdS@void@GR。采用多晶粉末X-射线衍射仪(XRD),扫描电镜(SEM),透射电镜(TEM),傅立叶变换红外光谱仪(FT-IR)和比表面积测定(BET)表征样品的晶体结构、微观形貌、元素组成和孔结构。采用光催化降解罗丹明B(RhB),采用紫外-可见漫反射光谱仪(DRS)和电感耦合等离子体质谱仪(ICP)测定Cd^(2+)浓度,分析该材料的光催化性能及抗光腐蚀性能。结果表明:Hollow CdS@void@GR的结构大小可通过PS模板大小、S/Cd比例、超声反应时间及TEOS量进行调控。在强光照射下,由于多级中空结构,中空CdS内核与中空GR外壳之间的协同效应,Hollow CdS@void@GR纳米复合材料表现出较强的光催化活性、优异的光催化稳定性和良好的抗光腐蚀作用。

Synthesis,Configuration Judgment and Potentiation Activity of (2S,3S,E)-4-(3,4-Dihydroxybenzylidene)-3-(3,4-dihydroxyphenyl)-5-oxotetrahydrofuran-2-carboxylic Acid

The title compound（2S,3S,E）-4-（3,4-dihydroxybenzylidene）-3-（3,4-dihydroxyphenyl）-5-oxotetrahydrofuran-2-carboxylic acid was synthesized and the 2D structure was characterized by ^1H-NMR ^13C-NMR and LCMS. The absolute configuration was determined by single-crystal X-ray diffraction of the key intermediate（2S,3S,E）-ethyl 4-（3,4-dimethoxybenzylidene）-3-（3,4-dimethoxyphenyl）-5-oxotetrahydrofuran-2-carboxylate. The crystal belongs to tetragonal system, space group P41 with a = 13.0665（2）, b = 13.0665（2）, c = 13.4735（2）A, V = 2300.4（6） A^3, Z = 4, Dc = 1.278 g/cm^3, μ（CuKα） = 0.801 mm^-1, F（000） = 936, S = 1.050, R = 0.0364 and wR（I 〉 2σ（I）） = 0.1071. X-ray diffraction results showed that the molecular structure is stabilized totally by Van der Waals force. The antibacterial activity tests showed that the title compound possesses slight synergistic effect against MRSA and Acinetobacter baumanii.

Synthesis and evaluation of poly(N-vinyl caprolactam)-co-tert-butyl acrylate as kinetic hydrate inhibitor

Low dosage kinetic hydrate inhibitors(KHIs)are a kind of alternative chemical additives to high dosage thermodynamic inhibitors for preventing gas hydrate formation in oil&gas production wells and transportation pipelines.In this paper,a new KHI,poly(N-vinyl caprolactam)-co-tert-butyl acrylate(PVCapco-TBA),was successfully synthesized with N-vinyl caprolactam(NVCap)and tert-butyl acrylate.The kinetic inhibition performances of PVCap-co-TBA on the formations of both structureⅠmethane hydrate and structureⅡnatural gas hydrate were investigated by measuring the onset times of hydrate formation under different conditions and compared with commercial KHIs such as PVP,PVCap and inhibex 501.The results indicated that PVCap-co-TBA outperformed these widely applied inhibitors for both structureⅠand structureⅡhydrates.At the same dosage of KHI,the maximum tolerable degree of subcooling under which the onset time of hydrate formation exceeded 24 hours for structureⅠhydrate was much lower than that for structureⅡhydrate.The inhibition strength increased with the increasing dosage of PVCap-co-TBA;The maximum tolerable degree of subcooling for the natural gas hydrate is more than10 K when the dosage was higher than 0.5%(mass)while it achieved 12 K when that dosage rose to0.75%(mass).Additionally,we found polypropylene glycol could be used as synergist at the dosage of 1.0%(mass)or so,under which the kinetic inhibition performance of PVCap-co-TBA could be improved significantly.All evaluation results demonstrated that PVCap-co-TBA was a very promising KHI and a competitive alternative to the existing commercial KHIs.

氢解脱苄反应钯基合金催化剂研究进展

氢解脱苄反应是有机合成较为关键的一步工艺。然而,贵金属钯(Pd)的使用以及使用过程中不可避免的流失,极大地增加了产品的成本。为此,开发高性能、长寿命、低成本氢解催化剂成为提升产品竞争力的核心技术。其中,Pd基合金催化剂由于协同效应、高稳定性和非贵金属部分替代而成为更具发展潜力的策略。因此,从氢解脱苄催化反应机理入手,综述近年来氢解脱苄反应Pd基合金催化剂取得的研究进展,讨论Pd基合金催化剂的设计原则、制备方法和合金效应,结合工业化氢解脱苄反应的特征,对Pd基合金催化剂的设计、制备、应用、回收作出总结和展望。

磷化锡作为锂/钠离子电池高性能负极的设计合成及性能提升策略

磷化锡(Sn_(4)P_(3))作为新型锂/钠离子电池(LIBs/SIBs)的负极材料,具有高理论容量和适宜的工作电位等突出优点。但常规结构的Sn_(4)P_(3)在循环过程中存在导电性差、体积变化剧烈、Sn团聚粗化等缺陷,会导致倍率性能差、容量衰减快、循环寿命短等问题,阻碍其实际应用。本文基于对近期研究文献的系统总结,归纳了提升Sn_(4)P_(3)负极性能的3种合成方法,即机械球磨法、溶剂热法和低温磷化法,以及3种增效策略,即纳米化与多级结构构筑、碳基材料复合和异质元素掺杂,并对目前面临的挑战及未来的发展前景进行了展望。

聚合物半导体光催化合成过氧化氢:光氧化还原中心的空间分离和协同利用

以地表丰富的水和/或氧气为原料,以太阳能为能量来源的光催化合成过氧化氢是面向碳中和的一个颇具吸引力的路径。近年来,以能带、活性位点、组成等可调的聚合物半导体为光催化剂,开展光合成过氧化氢的研究进入了新的高峰期。当前,该研究主要面临两大关键挑战:1)由于材料性质固有的限制,光氧化还原中心通常难以分离,导致光生电荷复合严重,使得光催化合成过氧化氢的活性较差;2)氧化还原中心的利用率低,多数情况下,只有氧化端或还原端参与过氧化氢的合成,另一侧则与牺牲剂反应消耗。对此,本文聚焦光氧化还原中心的空间分离和协同利用来阐述聚合物半导体光催化合成过氧化氢的最新进展。光氧化还原中心空间分离的关键是在聚合物中设计电子给体和供体单元,例如在聚合物框架中引入原子级金属,构建金属-有机给吸电子体系,或构建全有机给吸电子体系。根据氧化还原中心的光催化行为,协同利用主要分为以下三种模型:1)氧还原耦合有机分子氧化;2)水氧化耦合有机分子还原,3)氧还原耦合水氧化。在此基础上,本文详细探讨了针对上述两个关键挑战的调控模式、特性、催化机制和反应途径。最后,我们阐述了光催化合成过氧化氢的潜在应用,并展望了光催化合成过氧化氢中理性设计氧化还原中心协同利用模式的机遇和挑战。

赛克改性三聚氰胺甲醛树脂的合成及协效阻燃作用

采用固相合成法,通过六羟甲基三聚氰胺(HMM)与赛克醚化和缩聚合成了赛克改性三聚氰胺甲醛树脂(简称赛改树脂),并通过红外光谱和固体13C NMR表征了其结构。其较佳的合成条件:n(HMM)∶n(赛克)=1∶2.50,反应温度130℃,反应时间4 h。在此条件下,产品的质量产率为86.2%,水溶性为0.177 g·(100 mL)^(-1)水;赛克树脂的初始热稳定性、成炭能力和对聚丙烯(PP)的协效阻燃作用均好于HMM和赛克,例如HMM、赛克和赛改树脂的T5%分别为149、245和291℃,750℃时的残余率分别为9.48%、0.30%和12.14%,阻燃PP达到V-0级时,聚磷酸铵(APP)/赛改树脂、APP/HMM和APP/赛克的最小添加量分别为24%、34%和26%。PP/APP/赛改树脂的耐水性也明显好于PP/APP/赛克。