The work presents the synthesis and characterization of amidated pectin(AP) based polymer electrolyte membranes(PEM) crosslinked with glutaraldehyde(GA).The prepared membranes are characterized by Fourier transform in...The work presents the synthesis and characterization of amidated pectin(AP) based polymer electrolyte membranes(PEM) crosslinked with glutaraldehyde(GA).The prepared membranes are characterized by Fourier transform infrared spectroscopy(FTIR),organic elemental analysis,X-ray diffraction studies(XRD),thermogravimetric analysis (TGA) and impedance spectroscopy.Mechanical properties of the membranes are evaluated by tensile tests.The degree of amidation(DA),molar and mass reaction yields(Y_M and K_N) are calcu...展开更多
A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]py...A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.展开更多
The amide moiety plays an important role as a powerful bioactive backbone,and as the synthetic chemistry community moves toward more sp^(3)-rich scaffolds,alkyl halides have become the feedstock of choice for obtainin...The amide moiety plays an important role as a powerful bioactive backbone,and as the synthetic chemistry community moves toward more sp^(3)-rich scaffolds,alkyl halides have become the feedstock of choice for obtaining carbonylation products.With the development of photoredox catalysis,several aminocarbonylation systems for alkyl halides were developed which usually require transition metal catalysis.Considering the demands for green sustainable chemical synthesis,here we report a metal-free,exogenous catalyst-free aminocarbonylation reaction of alkyl iodides under atmospheric pressure of carbon monoxide.Through a combination of EDA and XAT strategies,the reaction occurs efficiently under only light irradiation at room temperature.展开更多
The development of innovative and sustainable catalytic strategies for organic synthesis is a pivotal aspect of advancing material science and chemical engineering.This research presents a new catalytic method for the...The development of innovative and sustainable catalytic strategies for organic synthesis is a pivotal aspect of advancing material science and chemical engineering.This research presents a new catalytic method for the aminoacylation of N-sulfonyl ketimines by utilizing a potassium-doped graphite-like carbon nitride(g-C_(3)N_(4))framework.This method not only enhances the catalytic efficiency and broadens the light absorption spectrum of g-C_(3)N_(4)but also significantly reduces the recombination rate of electronhole pairs,thereby increasing the reaction yield and selectivity.Importantly,our approach facilitates the synthesis of aminoacylated N-heterocycles,expanding the applicability of potassium-modified g-C_(3)N_(4)in photocatalytic organic synthesis.A notable accomplishment of this study is the unprecedented generation of carbamoyl radicals via heterogeneous photocatalysis,which can be easily recycled after reaction.This advancement highlights the capability of potassium-doped g-C_(3)N_(4)(namely K-CN)as an advanced heterogeneous photocatalyst for the formation of complex organic compounds.展开更多
The safety and performance of lithium-ion batteries(LIBs)largely depend on the structural design and performance characteristics of the separator.Commercial polyolefin separators suffer from problems such as poor ther...The safety and performance of lithium-ion batteries(LIBs)largely depend on the structural design and performance characteristics of the separator.Commercial polyolefin separators suffer from problems such as poor thermal stability,insufficient porosity,and inferior electrolyte wettability,which not only easily lead to battery safety issues but also significantly affect the ionic conductivity and energy density of the batteries.Herein,we have designed a facile,efficient and controllable methodology to develop a high-porosity poly(m-phenylene isophthalamide)(PMIA)separator with both excellent wettability and superior thermal resistance by a vapor-induced phase separation technique.Specifically,the PMIA separator undergoes a thermal shrinkage of less than 1%even after being treated at 200℃ for one hour,which greatly enhances the thermal safety of the battery.In addition,a continuous and interconnected high-porosity structure(porosity of 69%)is formed by utilizing a stable and controllable solvent exchange rate,thereby constructing abundant channels for the transportation of ions within the battery.Moreover,the amide groups in the PMIA molecular structure further confer the separator with excellent wettability,enabling it to possess outstanding electrolyte absorption capacity(electrolyte absorption rate of 270%).As a result,the Li||LFP full cell with PMIA separator exhibits excellent capacity and cycling stability,maintaining a reversible specific capacity of 105.6 mAh g^(-1)after 600 cycles at 5 C.And Li||NCM811 full cell with PMIA separator show no significant degradation(168.1 mAh g^(-1)at 0.5 C)after long-cycle at high temperature.These results indicate the potential of the PMIA separator for high thermal stability and high energy battery,and the scalability of this technology also provides new ideas and directions for the preparation of separators with superior comprehensive performance.展开更多
A visible light-promoted fast photochemical Wolff rearrangement was developed toward synthesis ofα-substituted amides in continuous flow with the use of a photochemical oscillatory flow reactor(POFR).The control expe...A visible light-promoted fast photochemical Wolff rearrangement was developed toward synthesis ofα-substituted amides in continuous flow with the use of a photochemical oscillatory flow reactor(POFR).The control experiment indicates that a fast process of the Wolff rearrangement(<40 s)is involved.Notably,this protocol does not require excess use of any reactants,and the resultingα-substituted amides could be isolated by recrystallization in good to excellent yields.展开更多
Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In ...Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.展开更多
Photocatalytic conversion of CO_(2) is pivotal for mitigating the global greenhouse effect and fostering sustainable energy development.Nowadays,polymeric carbon nitride(PCN)has gained widespread application in CO_(2)...Photocatalytic conversion of CO_(2) is pivotal for mitigating the global greenhouse effect and fostering sustainable energy development.Nowadays,polymeric carbon nitride(PCN)has gained widespread application in CO_(2) solar reduction due to its excellent visible light response,suitable conduction band position,and good cost-effectiveness.However,the amorphous nature and low conductivity of PCN limit its photocatalytic efficiency by leading to low carrier concentrations and facile electron–hole recombination during photocatalysis.Addressing this bottleneck,in this study,potassium-doped PCN(KPCN)/copper(Ⅱ)-complexed bipyridine hydroxyquinoline carboxylic acid(Cu(Ⅱ)(bpy)(H_(2)hqc))composite catalysts were synthesized through a multistep microwave heating process.In the composite,the formation of an S-scheme junction facilitates the enrichment of more negative electrons on the conduction band of KPCN via intermolecular electron–hole recombination between Cu(Ⅱ)(bpy)(H_(2)hqc)(CuPyQc)and KPCN,thereby promoting efficient photoreduction of CO_(2) to CO.Microwave heating enhances the amidation reaction between these two components,achieving the immobilization of homogeneous molecular catalysts and forming amidation chemical bonds that serve as key channels for the S-scheme charge transfer.This work not only presents a new PCN-based catalytic system for CO_(2) reduction applications,but also offers a novel microwave-practical approach for immobilizing homogeneous catalysts.展开更多
A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible ...A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups.The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.展开更多
Identifying chemical structures inhuman-derived samples presents significant challenges due to limited structural data obtained from untargeted metabolomics studies.When the chemical structures of molecules are closel...Identifying chemical structures inhuman-derived samples presents significant challenges due to limited structural data obtained from untargeted metabolomics studies.When the chemical structures of molecules are closely related to the phenotypic status of human ecosystems,it becomes invaluable to devise a method for efficiently and systematically determining structures that correlate with the pathophysiological status of humans in a high-throughput approach.展开更多
Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membr...Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.展开更多
Catalytic Michael addition reaction represents a fundamental importance in organic synthetic chemistry.Whereas corresponding conversions toward intrinsically low reactive enamide remains an ongoing challenging.We here...Catalytic Michael addition reaction represents a fundamental importance in organic synthetic chemistry.Whereas corresponding conversions toward intrinsically low reactive enamide remains an ongoing challenging.We herein report a copper-catalyzed conjugate addition of allenes toβ-substituted alkenyl amides,one of the most challenging Michael acceptors.The present method utilizes readily available allenes as the latent carbon-based nucleophiles and simple,commonβ-substituted alkenyl amides as starting materials,unlike previous methods that usually preinstall an activating group to improve the reactivity of amide or uses highly reactive stoichiometric quantities of organometallics.Hence,this approach shows good functional group compatibility and can be implemented under mild reaction conditions with excellent level of chemo-and regioselectivities.展开更多
Selective molecular recognition in water is routine for bioreceptors,but remains challenging for synthetic hosts.This is principally because noncovalent interactions are usually less efficient in aqueous environments....Selective molecular recognition in water is routine for bioreceptors,but remains challenging for synthetic hosts.This is principally because noncovalent interactions are usually less efficient in aqueous environments.By mimicking the cavity feature of bioreceptors,Prof.Wei Jiang proposed and clarified the concept of“endo-functionalized cavity”.Through situating polar binding sites into a deep hydrophobic cavity,we designed and synthesized several macrocyclic hosts,among which amide naphthotubes are the most representative.The hosts can selectively recognize various polar molecules including organic micropollutants,drug molecules,and chiral molecules in water by employing the hydrophobic effect and shielded hydrogen bonding.In addition,these biomimetic hosts have been applied in spectroscopic analysis,adsorptive separation and self-assembly.In this review,we provide an overview of recent advances on amide naphthotubes with special emphasis on the efforts of Jiang's group.We are convinced that these biomimetic macrocycles will make further contributions to supramolecular chemistry and beyond.展开更多
Colorectal cancer is a common cancer worldwide.Traditional chemotherapeutic drugs often face limitations such as poor aqueous solubility and high systemic toxicity,which can lead to adverse side effects and limited th...Colorectal cancer is a common cancer worldwide.Traditional chemotherapeutic drugs often face limitations such as poor aqueous solubility and high systemic toxicity,which can lead to adverse side effects and limited therapeutic efficacy.In this study,a library of one kind of biodegradable and biocompatible polymer,leucine based-poly(ester amide)s(Leu-PEAs)was developed and utilized as drug carrier.The structure of Leu-PEAs can be tuned to alter their physicochemical properties,enhancing drug loading capacity and delivery efficiency.Leu-PEAs can self-assemble into nanoparticles by nanoprecipitation and load paclitaxel(PTX)with the diameter of~108 nm and PTX loading capacity of~8.5%.PTX-loaded Leu-PEAs nanoparticles(PTX@Leu-PEAs)demonstrated significant inhibition of CT26 cell growth in vitro.In vivo,these nanoparticles exhibited prolonged tumor accumulation and antitumor effects,with no observed toxicity to normal organs.Furthermore,blank Leu-PEAs nanoparticles also showed antitumor effects in vitro and in vivo,which may be attributed to the activation of the mammalian target of rapamycin(m TOR)pathway by leucine.Consequently,this biocompatible Leu-PEAs nano-drug delivery system shows potential as a promising strategy for colorectal cancer treatment,warranting further investigation.展开更多
An atom economicβ-C(sp^(3))−H chlorination of amide derivatives has been developed.This mild protocol employs CuCl_(2) instead of palladium catalysts with atom-economic HCl as chlorine sources and enables the late-st...An atom economicβ-C(sp^(3))−H chlorination of amide derivatives has been developed.This mild protocol employs CuCl_(2) instead of palladium catalysts with atom-economic HCl as chlorine sources and enables the late-stage functionalization of medicine derivatives.Mechanism studies suggest a plausible visible light triggered ligand-to-metal charge transfer(LMCT)/1,4-hydrogen atom transfer(HAT)cascade.展开更多
The pursuit of incorporating eco-friendly reinforcing agents in polymer composites has accentuated the exploration of various natural biomass-derived materials.The burgeoning environmental crisis spurred by the discha...The pursuit of incorporating eco-friendly reinforcing agents in polymer composites has accentuated the exploration of various natural biomass-derived materials.The burgeoning environmental crisis spurred by the discharge of synthetic dyes into wastewater has catalyzed the search for effective and sustainable treatment technologies.Among the various sorbent materials explored,biochar,being renewable,has gained prominence due to its excellent adsorption properties and environmental sustainability.It has also emerged as a focal point for its potential to replace other conventional reinforcing agents,viz.,fumed silica,aluminum oxide,treated clays,etc.This study introduces a novel class of polymer nanocomposites comprising of lignin-based biochar particles and poly(ester amide urethane)matrix via a feasible method.The structural evaluation of these nanocomposites was accomplished using Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,and powder X-ray diffraction.The polymer nanocomposites exhibited superior mechanical properties with an increment in tensile strength factor by 45%in comparison to its pristine matrix,along with an excellent toughness value of 90.22 MJm^(−3)at a low loading amount of only 1 wt%.The composites showed excellent improvement in thermal properties with a sharp rise in the glass transition temperature(Tg)value from−28.15℃to 84℃,while also championing sustainability through inherent biodegradability attributes.Beyond their structural prowess,these polymer nanocomposites demonstrated excellent potential as adsorbents,displaying efficient removal of malachite green and tartrazine dyes from aqueous systems with a removal efficiency of 87.25%and 73.98%,respectively.The kinetics study revealed the pseudo second order model to be the precision tool to assess the dye removal study.Complementing this,the Langmuir adsorption isotherm provided a framework to assess the sorption features of the polymer nanocomposites.Overall,these renewable biochar integrated polymer matrices boast remarkable recovery capabilities up to seven cycles of usage with an excellent dye recovery percentage of 95.21%for the last cycle,thereby defining sustainability as well as economic feasibility.展开更多
Aim To synthesize the tripepide Weinreb amide Boc Asp(OBzl) β Ala Asp(OBzl) N(OMe)Me (7) as a useful precursor of aspartyl peptide aldehyde derivatives; Methods DCC, IBCF method was used for preparation of ...Aim To synthesize the tripepide Weinreb amide Boc Asp(OBzl) β Ala Asp(OBzl) N(OMe)Me (7) as a useful precursor of aspartyl peptide aldehyde derivatives; Methods DCC, IBCF method was used for preparation of Weinreb amide; N hydroxysuccinimide activated ester was used in peptide synthesis; and Boc as N protecting group of amino acid. Results Boc Asp(OBzl) N(OMe)Me (3), Boc β Ala Asp(OBzl) N(OMe)Me (5), and Boc Asp(OBzl) β Ala Asp(OBzl) N(OMe)Me (7) were synthesized successfully. Conclusion An useful precursor of tripeptide aspartyl aldehydes was synthesized.展开更多
文摘The work presents the synthesis and characterization of amidated pectin(AP) based polymer electrolyte membranes(PEM) crosslinked with glutaraldehyde(GA).The prepared membranes are characterized by Fourier transform infrared spectroscopy(FTIR),organic elemental analysis,X-ray diffraction studies(XRD),thermogravimetric analysis (TGA) and impedance spectroscopy.Mechanical properties of the membranes are evaluated by tensile tests.The degree of amidation(DA),molar and mass reaction yields(Y_M and K_N) are calcu...
文摘A trinuclear copper complex [Cu_(3)(L2)_(2)(SO_(4))_(2)(H_(2)O)_(7)]·8H_(2)O(1)(HL2=1-hydroxy-3-(pyrazin-2-yl)-N-(pyrazin-2-ylmethyl)imidazo[1,5-a]pyrazine-8-carboxamide) with a multi-substituted imidazo[1,5-a]pyrazine scaffold was serendipitously prepared from the reaction of the pro-ligand of H_(2)L1(N,N'-bis(pyrazin-2-ylmethyl)pyrazine-2,3-dicarboxamide) with CuSO_(4)·5H_(2O) in aqueous solution at room temperature.Complex 1 was characterized by IR,single-crystal X-ray analysis,and magnetic susceptibility measurements.Single-crystal X-ray analysis reveals that the complex consists of three Cu(Ⅱ) ions,two in situ transformed L2~-ligands,two coordinated sulfates,seven coordinated water molecules,and eight uncoordinated water molecules.Magnetic susceptibility measurement indicates that there are obvious ferromagnetic coupling interactions between the adjacent Cu(Ⅱ) ions in 1.CCDC:1852713.
基金supported by National Key R&D Program of China(No.2023YFA1507500)the International Partnership Program of Chinese Academy of Sciences(No.028GJHZ2023045FN)。
文摘The amide moiety plays an important role as a powerful bioactive backbone,and as the synthetic chemistry community moves toward more sp^(3)-rich scaffolds,alkyl halides have become the feedstock of choice for obtaining carbonylation products.With the development of photoredox catalysis,several aminocarbonylation systems for alkyl halides were developed which usually require transition metal catalysis.Considering the demands for green sustainable chemical synthesis,here we report a metal-free,exogenous catalyst-free aminocarbonylation reaction of alkyl iodides under atmospheric pressure of carbon monoxide.Through a combination of EDA and XAT strategies,the reaction occurs efficiently under only light irradiation at room temperature.
基金financial support from the National Natural Science Foundation of China(No.22171249)the Science&Technology Innovation Talents in Universities of Henan Province(No.23HASTIT003)。
文摘The development of innovative and sustainable catalytic strategies for organic synthesis is a pivotal aspect of advancing material science and chemical engineering.This research presents a new catalytic method for the aminoacylation of N-sulfonyl ketimines by utilizing a potassium-doped graphite-like carbon nitride(g-C_(3)N_(4))framework.This method not only enhances the catalytic efficiency and broadens the light absorption spectrum of g-C_(3)N_(4)but also significantly reduces the recombination rate of electronhole pairs,thereby increasing the reaction yield and selectivity.Importantly,our approach facilitates the synthesis of aminoacylated N-heterocycles,expanding the applicability of potassium-modified g-C_(3)N_(4)in photocatalytic organic synthesis.A notable accomplishment of this study is the unprecedented generation of carbamoyl radicals via heterogeneous photocatalysis,which can be easily recycled after reaction.This advancement highlights the capability of potassium-doped g-C_(3)N_(4)(namely K-CN)as an advanced heterogeneous photocatalyst for the formation of complex organic compounds.
基金supported by the National Natural Science Foundation of China(52273059,52403046)the Science and Technology Plans of Tianjin(22JCYBJC01030)+1 种基金the Tianjin Research Innovation Project for Postgraduate Students(2022BKY145)partially supported by financial contributions from Yantai Tayho Advanced Materials Co.,Ltd。
文摘The safety and performance of lithium-ion batteries(LIBs)largely depend on the structural design and performance characteristics of the separator.Commercial polyolefin separators suffer from problems such as poor thermal stability,insufficient porosity,and inferior electrolyte wettability,which not only easily lead to battery safety issues but also significantly affect the ionic conductivity and energy density of the batteries.Herein,we have designed a facile,efficient and controllable methodology to develop a high-porosity poly(m-phenylene isophthalamide)(PMIA)separator with both excellent wettability and superior thermal resistance by a vapor-induced phase separation technique.Specifically,the PMIA separator undergoes a thermal shrinkage of less than 1%even after being treated at 200℃ for one hour,which greatly enhances the thermal safety of the battery.In addition,a continuous and interconnected high-porosity structure(porosity of 69%)is formed by utilizing a stable and controllable solvent exchange rate,thereby constructing abundant channels for the transportation of ions within the battery.Moreover,the amide groups in the PMIA molecular structure further confer the separator with excellent wettability,enabling it to possess outstanding electrolyte absorption capacity(electrolyte absorption rate of 270%).As a result,the Li||LFP full cell with PMIA separator exhibits excellent capacity and cycling stability,maintaining a reversible specific capacity of 105.6 mAh g^(-1)after 600 cycles at 5 C.And Li||NCM811 full cell with PMIA separator show no significant degradation(168.1 mAh g^(-1)at 0.5 C)after long-cycle at high temperature.These results indicate the potential of the PMIA separator for high thermal stability and high energy battery,and the scalability of this technology also provides new ideas and directions for the preparation of separators with superior comprehensive performance.
基金financial support from the National Natural Science Foundation of China(No.22208279)Financial support from the Fuzhou University(No.0041/511095)。
文摘A visible light-promoted fast photochemical Wolff rearrangement was developed toward synthesis ofα-substituted amides in continuous flow with the use of a photochemical oscillatory flow reactor(POFR).The control experiment indicates that a fast process of the Wolff rearrangement(<40 s)is involved.Notably,this protocol does not require excess use of any reactants,and the resultingα-substituted amides could be isolated by recrystallization in good to excellent yields.
文摘Chiral N-substituted amino amides and esters are ubiquitous scaffolds in pesticides and pharmaceutical chemicals,but their asymmetric synthesis remains challenging especially for those with multiple chiral centers.In this study,IR104 from Streptomyces aureocirculatus was identified from 157 wild-type imine reductases for the synthesis of(S)-2-((R)-2-oxo-4-propylpyrrolidin-1-yl)butanamide(antiepileptic drug Brivaracetam)via dynamic kinetic resolution reductive amination from ethyl 3-formylhexanoate and(S)-2-aminobutylamide with high diastereoselectivity.To further improve the catalytic efficiency of IR104,its mutant D191E/L195I/E253S/M258A(M3)was identified by saturation mutagenesis and iterative combinatorial mutagenesis,which exhibited a 102-fold increase in the catalytic efficiency relative to that of wild-type enzyme and high diastereoselectivity(98:2 d.r.).Crystal structural analysis and molecular dynamics simulations provided some insights into the molecular basis for the improved activity of the mutant enzyme.The imine reductase identified in this study could accept chiral amino amides/esters as amino donors for the dynamic kinetic resolution reductive amination of racemicα-substituted aldehydo-esters,expanding the substrate scope of imine reductases in the dynamic kinetic resolution-reductive amination.Finally,IR104-M3 was successfully used for the preparation of Brivaracetam at gram scale.Using this mutant,various N-substituted amino amides/esters with two chiral centers were also synthesized with up to 99:1 d.r.and 96%yields and subsequently converted intoγ-andδ-lactams,providing an efficient protocol for the synthesis of these important compounds via enzymatic dynamic kinetic resolution-reductive amination from simple building blocks.
基金supported by the National Natural Science Foundation of China(Nos.22106105 and 22201180)the Innovation Program of Shanghai Municipal Education Commission(No.2019-01-07-00-E00015)+2 种基金Shanghai Science and Technology Innovation Program(No.21DZ1206300)the Central Local Science and Technology Development Guidance Fund(No.YDZX20213100003002)Shanghai Science and Technology Commission Program(No.20060502200).
文摘Photocatalytic conversion of CO_(2) is pivotal for mitigating the global greenhouse effect and fostering sustainable energy development.Nowadays,polymeric carbon nitride(PCN)has gained widespread application in CO_(2) solar reduction due to its excellent visible light response,suitable conduction band position,and good cost-effectiveness.However,the amorphous nature and low conductivity of PCN limit its photocatalytic efficiency by leading to low carrier concentrations and facile electron–hole recombination during photocatalysis.Addressing this bottleneck,in this study,potassium-doped PCN(KPCN)/copper(Ⅱ)-complexed bipyridine hydroxyquinoline carboxylic acid(Cu(Ⅱ)(bpy)(H_(2)hqc))composite catalysts were synthesized through a multistep microwave heating process.In the composite,the formation of an S-scheme junction facilitates the enrichment of more negative electrons on the conduction band of KPCN via intermolecular electron–hole recombination between Cu(Ⅱ)(bpy)(H_(2)hqc)(CuPyQc)and KPCN,thereby promoting efficient photoreduction of CO_(2) to CO.Microwave heating enhances the amidation reaction between these two components,achieving the immobilization of homogeneous molecular catalysts and forming amidation chemical bonds that serve as key channels for the S-scheme charge transfer.This work not only presents a new PCN-based catalytic system for CO_(2) reduction applications,but also offers a novel microwave-practical approach for immobilizing homogeneous catalysts.
基金financial support from the National Natural Science Foundation of China(No.82003585)the Program for Science&Technology Innovation Talents in Universities of Henan Province(No.24HASTIT069)+5 种基金the Technical Innovation Team of Henan Normal University(No.2022TD03)the Special Project for Fundamental Research in University of Henan Province(No.23ZX009)the Henan Science and Technology Program(No.232102310364)the Key Project of Henan Educational Committee(No.22A150041)Excellent Youth Foundation of Henan Scientific Committee(No.222300420012)the Young Core Instructor Training Program of Xinyang Agriculture and Forestry University(2023)。
文摘A transition-metal-and oxidant-free amination/cyclization reaction to access 1,2,4-triazolo[1,5-a]pyridines was realized in water by using amino diphenylphosphinate as amino source.A broad array of readily accessible N-(pyridyl)amides could be converted into the products featuring a diverse set of functional groups.The sustainable methodology was successfully applied to the late-stage functionalization of natural products and drugs.
基金supported by the National Natural Science Foundation of China(Nos.81930109 and 82321005)。
文摘Identifying chemical structures inhuman-derived samples presents significant challenges due to limited structural data obtained from untargeted metabolomics studies.When the chemical structures of molecules are closely related to the phenotypic status of human ecosystems,it becomes invaluable to devise a method for efficiently and systematically determining structures that correlate with the pathophysiological status of humans in a high-throughput approach.
基金finically supported by the National Natural Science Foundation of China(22075055)the Guangxi Science and Technology Project(AB16380030)。
文摘Transition metal-nitrogen-carbon(M-N-C)as a promising substitute for the conventional noble metalbased catalyst still suffers from low activity and durability for oxygen reduction reaction(ORR)in proton exchange membrane fuel cells(PEMFCs).To tackle the issue,herein,a new type of sulfur-doped ironnitrogen-hard carbon(S-Fe-N-HC)nanosheets with high activity and durability in acid media were developed by using a newly synthesized precursor of amide-based polymer with Fe ions based on copolymerizing two monomers of 2,5-thiophene dicarboxylic acid(TDA)as S source and 1,8-diaminonaphthalene(DAN)as N source via an amination reaction.The as-synthesized S-Fe-N-HC features highly dispersed atomic Fe Nxmoieties embedded into rich thiophene-S doped hard carbon nanosheets filled with highly twisted graphite-like microcrystals,which is distinguished from the majority of M-N-C with soft or graphitic carbon structures.These unique characteristics endow S-Fe-N-HC with high ORR activity and outstanding durability in 0.5 M H_(2)SO_(4).Its initial half-wave potential is 0.80 V and the corresponding loss is only 21 m V after 30,000 cycles.Meanwhile,its practical PEMFC performance is a maximum power output of 628.0 mW cm^(-2)and a slight power density loss is 83.0 m W cm^(-2)after 200-cycle practical operation.Additionally,theoretical calculation shows that the activity of Fe Nxmoieties on ORR can be further enhanced by sulfur doping at meta-site near FeN_(4)C.These results evidently demonstrate that the dual effect of hard carbon substrate and S doping derived from the precursor platform of amid-polymers can effectively enhance the activity and durability of Fe-N-C catalysts,providing a new guidance for developing advanced M-N-C catalysts for ORR.
基金the financial support from the National Natural Science Foundation of China(NSFC,Nos.22171042,21831002,and 22193012)the Jilin Province Natural Science Foundation(No.20160520140JH)+1 种基金the Fundamental Research Funds for the Central Universitiesthe Ten Thousand Talents Program for generous financial support。
文摘Catalytic Michael addition reaction represents a fundamental importance in organic synthetic chemistry.Whereas corresponding conversions toward intrinsically low reactive enamide remains an ongoing challenging.We herein report a copper-catalyzed conjugate addition of allenes toβ-substituted alkenyl amides,one of the most challenging Michael acceptors.The present method utilizes readily available allenes as the latent carbon-based nucleophiles and simple,commonβ-substituted alkenyl amides as starting materials,unlike previous methods that usually preinstall an activating group to improve the reactivity of amide or uses highly reactive stoichiometric quantities of organometallics.Hence,this approach shows good functional group compatibility and can be implemented under mild reaction conditions with excellent level of chemo-and regioselectivities.
基金the National Natural Science Foundation of China(Nos.22174059 and 22201128)Hunan Provincial Natural Science Foundation of China(Nos.2022JJ40363 and 2022JJ40365)+1 种基金the Young Science and Technology Innovation Program of Hunan Province(No.2022RC1230)China Postdoctoral Science Foundation(No.2022M721542)for financial support。
文摘Selective molecular recognition in water is routine for bioreceptors,but remains challenging for synthetic hosts.This is principally because noncovalent interactions are usually less efficient in aqueous environments.By mimicking the cavity feature of bioreceptors,Prof.Wei Jiang proposed and clarified the concept of“endo-functionalized cavity”.Through situating polar binding sites into a deep hydrophobic cavity,we designed and synthesized several macrocyclic hosts,among which amide naphthotubes are the most representative.The hosts can selectively recognize various polar molecules including organic micropollutants,drug molecules,and chiral molecules in water by employing the hydrophobic effect and shielded hydrogen bonding.In addition,these biomimetic hosts have been applied in spectroscopic analysis,adsorptive separation and self-assembly.In this review,we provide an overview of recent advances on amide naphthotubes with special emphasis on the efforts of Jiang's group.We are convinced that these biomimetic macrocycles will make further contributions to supramolecular chemistry and beyond.
基金support of the National Natural Science Foundation of China(Nos.52173150,52073313)the Guangzhou Science and Technology Program City-University Joint Funding Project(No.2023A03J0001)the Shenzhen Science and Technology Program(No.KCXFZ 202002011010232)。
文摘Colorectal cancer is a common cancer worldwide.Traditional chemotherapeutic drugs often face limitations such as poor aqueous solubility and high systemic toxicity,which can lead to adverse side effects and limited therapeutic efficacy.In this study,a library of one kind of biodegradable and biocompatible polymer,leucine based-poly(ester amide)s(Leu-PEAs)was developed and utilized as drug carrier.The structure of Leu-PEAs can be tuned to alter their physicochemical properties,enhancing drug loading capacity and delivery efficiency.Leu-PEAs can self-assemble into nanoparticles by nanoprecipitation and load paclitaxel(PTX)with the diameter of~108 nm and PTX loading capacity of~8.5%.PTX-loaded Leu-PEAs nanoparticles(PTX@Leu-PEAs)demonstrated significant inhibition of CT26 cell growth in vitro.In vivo,these nanoparticles exhibited prolonged tumor accumulation and antitumor effects,with no observed toxicity to normal organs.Furthermore,blank Leu-PEAs nanoparticles also showed antitumor effects in vitro and in vivo,which may be attributed to the activation of the mammalian target of rapamycin(m TOR)pathway by leucine.Consequently,this biocompatible Leu-PEAs nano-drug delivery system shows potential as a promising strategy for colorectal cancer treatment,warranting further investigation.
基金support from the University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province(No.UNPYSCT-2017124).
文摘An atom economicβ-C(sp^(3))−H chlorination of amide derivatives has been developed.This mild protocol employs CuCl_(2) instead of palladium catalysts with atom-economic HCl as chlorine sources and enables the late-stage functionalization of medicine derivatives.Mechanism studies suggest a plausible visible light triggered ligand-to-metal charge transfer(LMCT)/1,4-hydrogen atom transfer(HAT)cascade.
文摘The pursuit of incorporating eco-friendly reinforcing agents in polymer composites has accentuated the exploration of various natural biomass-derived materials.The burgeoning environmental crisis spurred by the discharge of synthetic dyes into wastewater has catalyzed the search for effective and sustainable treatment technologies.Among the various sorbent materials explored,biochar,being renewable,has gained prominence due to its excellent adsorption properties and environmental sustainability.It has also emerged as a focal point for its potential to replace other conventional reinforcing agents,viz.,fumed silica,aluminum oxide,treated clays,etc.This study introduces a novel class of polymer nanocomposites comprising of lignin-based biochar particles and poly(ester amide urethane)matrix via a feasible method.The structural evaluation of these nanocomposites was accomplished using Fourier-transform infrared spectroscopy,X-ray photoelectron spectroscopy,and powder X-ray diffraction.The polymer nanocomposites exhibited superior mechanical properties with an increment in tensile strength factor by 45%in comparison to its pristine matrix,along with an excellent toughness value of 90.22 MJm^(−3)at a low loading amount of only 1 wt%.The composites showed excellent improvement in thermal properties with a sharp rise in the glass transition temperature(Tg)value from−28.15℃to 84℃,while also championing sustainability through inherent biodegradability attributes.Beyond their structural prowess,these polymer nanocomposites demonstrated excellent potential as adsorbents,displaying efficient removal of malachite green and tartrazine dyes from aqueous systems with a removal efficiency of 87.25%and 73.98%,respectively.The kinetics study revealed the pseudo second order model to be the precision tool to assess the dye removal study.Complementing this,the Langmuir adsorption isotherm provided a framework to assess the sorption features of the polymer nanocomposites.Overall,these renewable biochar integrated polymer matrices boast remarkable recovery capabilities up to seven cycles of usage with an excellent dye recovery percentage of 95.21%for the last cycle,thereby defining sustainability as well as economic feasibility.
文摘Aim To synthesize the tripepide Weinreb amide Boc Asp(OBzl) β Ala Asp(OBzl) N(OMe)Me (7) as a useful precursor of aspartyl peptide aldehyde derivatives; Methods DCC, IBCF method was used for preparation of Weinreb amide; N hydroxysuccinimide activated ester was used in peptide synthesis; and Boc as N protecting group of amino acid. Results Boc Asp(OBzl) N(OMe)Me (3), Boc β Ala Asp(OBzl) N(OMe)Me (5), and Boc Asp(OBzl) β Ala Asp(OBzl) N(OMe)Me (7) were synthesized successfully. Conclusion An useful precursor of tripeptide aspartyl aldehydes was synthesized.
