A nickel-catalyzed C(sp^(2))–H alkynylation of unprotected α-substituted benzylamines is achieved by utilizing a transient directing group. The combination of a TDG with a nickel catalyst significantly improves the ...A nickel-catalyzed C(sp^(2))–H alkynylation of unprotected α-substituted benzylamines is achieved by utilizing a transient directing group. The combination of a TDG with a nickel catalyst significantly improves the reaction step and atom economy. It has been investigated that the 2,4,6-trimethylpyridine ligand was critical to achieve the optimized reactivity. This protocol provides a straightforward route for synthesizing the alkynylated free benzylamines, featuring good substrate compatibility and monoselectivity.展开更多
The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundan...The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundance of hydrocarbon compounds,and the potential for late-stage functionalization of complex organic molecules.The ortho-and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years,however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states.The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds.This review aims to summarize the strategies for controlling para-selective C–H functionalization using the directing group,template engineering,and catalyst/ligand design under transition metals catalysis in recent years.展开更多
The directing mechanisms of liquid directing agents of zeolite Y and zeolite L were studied by means of light transmission, ultracentrifugation, NMR, XRD and “cross-exchange” experiments. It was discovered that not ...The directing mechanisms of liquid directing agents of zeolite Y and zeolite L were studied by means of light transmission, ultracentrifugation, NMR, XRD and “cross-exchange” experiments. It was discovered that not only microcfystals of zeolites, but also cage structures of zeolites play the directing role for crystallization of zeolites.展开更多
In this work,we show for the first time that high-silica zeolites(MFI,TON,MTT,and*MRE)could be synthesized from a combined strategy of both zeolite seeding and alcohol filling in the absence of organic structure-direc...In this work,we show for the first time that high-silica zeolites(MFI,TON,MTT,and*MRE)could be synthesized from a combined strategy of both zeolite seeding and alcohol filling in the absence of organic structure-directing agents(OSDAs).High-silica ZSM-5 zeolites with Si/Al ratios ranging from 38 to 240(TF-Al-ZSM-5)could be synthesized via this route.The key to the success of this technique was the employment of an aluminosilicate precursor with a fully 4-coordinated aluminum species as the initial source,wherein the rearrangement and condensation of the silicate species,rather than the aluminate species,occurred during zeolite crystallization.In addition,heteroatoms,such as Fe and B,could be incorporated into the zeolite frameworks.Catalytic tests for the methanol-to-propylene(MTP)reaction exhibited good catalytic performance for TF-Al-ZSM-5,which was comparable to that of the aluminosilicate ZSM-5 zeolite synthesized with OSDAs.Hence,this method offers viable opportunities for the industrial production and catalytic application of high-silica zeolites in the future.展开更多
Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to ...Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to develop an eco‐friendly and nuisanceless OSDA for zeolite synthesis.Herein,choline is employed as a non‐toxic and green OSDA to synthesize high silica Y zeolite with SiO2/Al2O3 ratios of 6.5–6.8.The prepared Y zeolite samples exhibited outstanding(hydro)thermal stability at ultrahigh temperature owing to the higher SiO2/Al2O3 ratio.The XRF,SEM,29Si‐NMR and 13Na+results suggested that choline plays a structure‐directing role in the synthesis of Y zeolite,while the feed molar fraction of Na+is a crucial determinant for the framework SiO2/Al2O3 ratio and the crystal morphology.展开更多
Zeolite FAU composites with a macro/meso-microporous hierarchical structure were hydrothermally synthesized using macro-mesoporous γ-Al_2O_3 monolith as the substrate by means of the liquid crystallization directing...Zeolite FAU composites with a macro/meso-microporous hierarchical structure were hydrothermally synthesized using macro-mesoporous γ-Al_2O_3 monolith as the substrate by means of the liquid crystallization directing agent(LCDA) induced method. No template was needed throughout the synthesis processes. The structure and porosity of zeolite composites were analyzed by means of X-ray powder diffraction(XRD), scanning electron microscopy(SEM) and N_2adsorption-desorption isotherms. The results showed that the supported zeolite composites with varied zeolitic crystalline phases and different morphologies can be obtained by adjusting the crystallization parameters, such as the crystallization temperature, the composition and the alkalinity of the precursor solution. The presence of LCDA was defined as a determinant for synthesizing the zeolite composites. The mechanisms for formation of the hierarchically porous FAU zeolite composites in the LCDA induced synthesis process were discussed. The resulting monolithic zeolite with a trimodal-porous hierarchical structure shows potential applicability where facile diffusion is required.展开更多
Reported herein is the first example of heterogeneous palladium catalyzed C(sp^(3))-H bonds arylation by a transient-ligand-directed strategy.Using supported palladium(metallic state) na nopariticles as catalyst,a wid...Reported herein is the first example of heterogeneous palladium catalyzed C(sp^(3))-H bonds arylation by a transient-ligand-directed strategy.Using supported palladium(metallic state) na nopariticles as catalyst,a wide range of aryl iodides undergo the coupling with various o-methylbenzaldehyde derivatives to assemble a library of highly selective and functionalized o-benzylbenzaldehydes.The stability of the catalyst was easily recovered four runs without significant loss of activity.The XPS analysis of the catalyst before and after reaction indicated that the reaction might be carried out by a catalytic cycle starting with Pd~0.展开更多
Silicoaluminophosphates SAPO-11 molecular sieves with small particle size and hierarchical pores were synthesized using the directing agent method.The effect of crystallization time on the particle structure,morpholog...Silicoaluminophosphates SAPO-11 molecular sieves with small particle size and hierarchical pores were synthesized using the directing agent method.The effect of crystallization time on the particle structure,morphology,pore structure properties,and acid properties of SAPO-11 molecular sieves were investigated.Unlike the SAPO-11 molecular sieves synthesized with the conventional method,the results of XRD,SEM,BET and NH3-TPD analyses showed that the SAPO-11 molecular sieves synthesized by the directing agent method in a shorter crystallization time exhibited fine and uniform morphology.By increasing the crystallization time,the particle size of SAPO-11 molecular sieve was significantly reduced,and the mesoporous structure(intercrystalline pores)was formed.Furthermore,the external specific surface area and the total specific surface area reached 81.7 m^2/g and 192.0 m^2/g,respectively,which effectively reduced the pore mass transfer resistance and significantly increased the number of acid sites.The results of n-dodecane hydroisomerization revealed that the Pt/SAPO-11 prepared with the novel method exhibited higher catalytic activity and better hydroisomerization selectivity than that synthesized by the conventional hydrothermal method.Thus,the small particle molecular sieve showed a promising industrial application prospect to be used as catalyst support.展开更多
In this review, we highlight the recent development in Ru（II）-catalyzed C-H activations under redox neutral conditions. After a brief introduction of the C-H activations with oxidizing direct group by different tran...In this review, we highlight the recent development in Ru（II）-catalyzed C-H activations under redox neutral conditions. After a brief introduction of the C-H activations with oxidizing direct group by different transition metal catalysts, the examples with Ru（ll） catalyst were classified and introduced according to different internal oxidants used in the system. The features of each methodology will be highlighted and the plausible reaction mechanism will be presented if available.展开更多
Article 1 These regulations are formulated according to the rules of the State Law on foreign investment and the requirements of industrial policies to direct foreign investment, ensuring that it adapts to the program...Article 1 These regulations are formulated according to the rules of the State Law on foreign investment and the requirements of industrial policies to direct foreign investment, ensuring that it adapts to the programmes of China’s national economy and social development and protecting the legal rights and interests of investors.展开更多
Non-surfactant diquaternary ammonium compounds have already been used for obtaining various zeolites in nanocrystalline form. However, facile synthesis of nanocrystals of mordenite (MOR) and beta (BEA) in this way rem...Non-surfactant diquaternary ammonium compounds have already been used for obtaining various zeolites in nanocrystalline form. However, facile synthesis of nanocrystals of mordenite (MOR) and beta (BEA) in this way remains challenging. Here, we present the direct synthesis of nanosized mordernite (MOR) and beta (BEA) zeolites with hexane- and p-xylene-bridged bis-methylpyrrolidinium, -methylpiperidinium and -DABCO diquats, which can be synthesized in a single step from common chemicals. Optimized recipes are presented for nanosized MOR (20–50 nm) and BEA (15–30 nm) zeolites. By investigating the solid products obtained during hydrothermal synthesis, the formation of nanocrystals can be linked to the strong interaction between diquat templates and aluminosilicate species during the induction stage, which limits the amorphous precursor particles to a size below 50 nm. Based on the textural and acidic properties, catalytic performance data are discussed evidencing the clear benefits of these nanosized zeolites over bulk reference samples in Friedel–Crafts reactions and n-alkane hydroconversion.展开更多
Organoboron compounds have garnered significant attention in the fields of organic synthesis,materials science,medicinal chemistry and fine chemicals.In the past few decades,transition metal-catalyzed C–H borylation ...Organoboron compounds have garnered significant attention in the fields of organic synthesis,materials science,medicinal chemistry and fine chemicals.In the past few decades,transition metal-catalyzed C–H borylation has been developed rapidly and efficiently.In recent years,in order to explore eco-friendly,economical and efficient method for constructing C–B bond,chemists are dedicated to developing metalfree BX_(3)-mediated borylation.In this review,we present a systematic and comprehensive overview of the borylation driven by BX_(3) with different directing group auxiliary in the fields of organic synthesis and boron-containing organic materials since 2010,including(1)nitrogen directed C–H borylation,(2)oxygen directed C–H borylation,(3)sulfur directed C–H borylation and(4)phosphorus directed C–H borylation.The methods of borylation processes as well as the substance scopes,limits,and mechanisms of these routes are also discussed.展开更多
Advanced solid-state NMR techniques,including PT-J-HMQC ^(27)Al/^(31)P double-resonance NMR,2D ^(31)P and 1H DQ-SQ MAS NMR experiments,have been used to study the structure-directing effect in the crystallization of t...Advanced solid-state NMR techniques,including PT-J-HMQC ^(27)Al/^(31)P double-resonance NMR,2D ^(31)P and 1H DQ-SQ MAS NMR experiments,have been used to study the structure-directing effect in the crystallization of the molecular sieve AlPO_(4) -11 synthesized by a solvent-free method.展开更多
We report a computational study of the distribution of germanium ions among the double four-membered rings(D4Rs)in SCM-14 germanosilicate and the influence of a structure-directing agent(SDA)on the stability of the as...We report a computational study of the distribution of germanium ions among the double four-membered rings(D4Rs)in SCM-14 germanosilicate and the influence of a structure-directing agent(SDA)on the stability of the as-synthesized material.For the pure zeolite structure,the calculations suggested clustering of Ge ions and the formation of D4Rs populated entirely by Ge heteroatoms,while part of the D4Rs contain only Si as T-atoms.As a general trend,structures with more Ge–O–Ge bridges are more stable.展开更多
Rational design of organic structure-directing agents(OSDAs)is always regarded as a promising strategy to produce ZSM-48 with diverse configurations.However,to date,only OSDAs with alkyl and alkenyl groups have been e...Rational design of organic structure-directing agents(OSDAs)is always regarded as a promising strategy to produce ZSM-48 with diverse configurations.However,to date,only OSDAs with alkyl and alkenyl groups have been employed to produce ^(*)MRE zeolites with different structures.Aromatic heterocyclic groups were rarely considered for the synthesis of ZSM-48 with a unique nanostructure.In this work,a triazine-based bolaform quaternary ammonium bifunctional template was designed for the first time to fabricate nanorod stacked hierarchical ZSM-48(NSH-ZSM-48).Nanorod-stacked ZSM-48 with different SiO_(2)/Al_(2)O_(3) ratios ranging from 100 to 500 was obtained via a conventional procedure,using the synthesized s-triazine based OSDA,and a reasonable formation mechanism was proposed based on geometrical matching.We also demonstrated that the ZSM-48 nanorods piled up to form an ordered bird’s nest-like hollow sphere configuration.The synthesized NSH-ZSM-48 possesses abundant mesopores and a high surface area,attributed to the SDA’s mesopore-forming and nanonrod’s stacking abilities.In contrast to conventional materials,1 wt%Pd/NSH-ZSM-48 experiences a dramatic increase in the conversion(3.59%)and selectivity(95.7%)of a cyclohexanol/cyclohexanone mixture in the selective oxidation of cyclohexane,which are higher than those for silicalite-1 and SBA-15 with the same loading(2.11%/66.1%and 1.76%/68.5%,respectively).展开更多
Fluoroalkoxylated heterocycles,such as indoles,holds significant importance in pharmaceuticals and biology.Herein,we report a copper-mediated C4-H fluoroalkoxylation reaction of indoles via a transient directing group...Fluoroalkoxylated heterocycles,such as indoles,holds significant importance in pharmaceuticals and biology.Herein,we report a copper-mediated C4-H fluoroalkoxylation reaction of indoles via a transient directing group(TDG)strategy.This reaction exhibits excellent regioselectivity and broad functional group compatibility,offering a new approach for the synthesis of fluoroalkoxylated indoles.The reaction also represents an unprecedented example of 3d-transition metal-catalyzed C-H fluoroalkoxylation via a TDG strategy.展开更多
A nickel-catalyzed cascade C(sp^(2))–H alkynylation/hydroamination of unprotectedα-substituted benzylamines is achieved using a transient directing group(TDG).The combination of a TDG with a nickel catalyst signific...A nickel-catalyzed cascade C(sp^(2))–H alkynylation/hydroamination of unprotectedα-substituted benzylamines is achieved using a transient directing group(TDG).The combination of a TDG with a nickel catalyst significantly improves the overall step-and atom-economy.Studies have shown that the p-trifluoromethylbenzoic acid ligand is critical for achieving C(sp^(2))–H alkynylation and subsequent intramolecular hydroamination.This protocol provides a straightforward and efficient route for synthesizing substituted 1H-isoindoles,featuring good substrate compatibility.展开更多
Garlic planting requires a single seed with a scaly bud upward and vertically.In this study,an automatic garlic seed directing device was designed for auxiliary garlic seeding by utilizing a seed placed funnel,a corre...Garlic planting requires a single seed with a scaly bud upward and vertically.In this study,an automatic garlic seed directing device was designed for auxiliary garlic seeding by utilizing a seed placed funnel,a correcting mechanism,and an automatic control system.Three factors influenced device performance:characteristics of garlic seeds,limited notch diameter of the seed placed funnel,and funnel taper of the seed placed funnel.The most optimal structural parameters of the seed placed funnel were determined via theoretical analysis.The research samples of Lanling and Jinxiang garlic were divided into three groups according to their respective sizes.3D design software(Solidworks)was used to simulate the above three factors and analyze their rules of action.The obtained simulation results demonstrated that the suitable range of funnel taper and limited notch diameter of seed placed funnel for the three groups of seed were from 40°to 60°and 6-8 mm,respectively.The bench test showed that when the funnel taper was 60°and the limited notch diameter was 10 mm,the success rates of the three groups’seeds in terms of scaly bud directing were 89.8%,91.6%and 96.6%respectively,which satisfied the agricultural requirements of garlic planting.Accordingly,the corresponding results may promote the study and improvement of garlic intelligent planting equipment.展开更多
Transition-metal catalyzed C--H functionalization of benzaldehydes is of great interest in organic synthesis. Herein, we developed a transient directing group assisted amidation of benzaldehydes catalyzed by rhodium c...Transition-metal catalyzed C--H functionalization of benzaldehydes is of great interest in organic synthesis. Herein, we developed a transient directing group assisted amidation of benzaldehydes catalyzed by rhodium catalyst. With the employment of 10 mol% of 4-trifluoromethyl aniline, the in situ generated imine groups as the directing group efficiently enable this transformation. By using this protocol, a wide range of benzaldehydes were efficiently converted into the corresponding N-（2-formylphenyl）benzamides utilizing dioxazolones as the nitrogen source.展开更多
Acetolactate synthase(ALS)-targeting herbicides are among the most widely used weed-control chemicals globally.Mutations in the ALS gene can confer herbicide resistance in crops,thereby allowing selective elimination ...Acetolactate synthase(ALS)-targeting herbicides are among the most widely used weed-control chemicals globally.Mutations in the ALS gene can confer herbicide resistance in crops,thereby allowing selective elimination of weeds without harming crops.Herbicide-resistant ALS alleles were initially discovered in weeds and subsequently developed through artificial mutagenesis techniques.With the advancement of CRISPR/Cas technologies,various genome-editing tools are now available to introduce these resistant alleles,as well as novel variants,into diverse crop species.Moreover,emerging methodologies,such as directed evolution,enable the generation and screening of large populations of random ALS mutants.Consequently,ALS has become one of the most extensively targeted genes in plant gene evolution.This paper provides a comprehensive overview of both conventional and recently developed strategies for ALS evolution,with particular emphasis on CRISPR/Cas-based genome editing and directed evolution.Future perspectives on technological application are also discussed.By advancing our understanding of herbicide-resistant ALS allele development for crop improvement,these methodologies may also pave the way for their application to the evolution of other agronomically important genes.展开更多
基金supported financially by the Excellent Going Abroad Expert's Training Program in Hebei Province (No. 201940)the Hebei Natural Science Foundation of China (No. H2020208030)the S & T Program of Hebei (No. 22567607H) for financial support。
文摘A nickel-catalyzed C(sp^(2))–H alkynylation of unprotected α-substituted benzylamines is achieved by utilizing a transient directing group. The combination of a TDG with a nickel catalyst significantly improves the reaction step and atom economy. It has been investigated that the 2,4,6-trimethylpyridine ligand was critical to achieve the optimized reactivity. This protocol provides a straightforward route for synthesizing the alkynylated free benzylamines, featuring good substrate compatibility and monoselectivity.
基金support from the National Natural Science Foundation of China(No.21901206)Postdoctoral Science Foundation of China(No.2022M712589)+2 种基金General Key R&D Projects in Shaanxi Province(No.2023-YBGY-321)Natural Science Foundation of Chongqing(No.CSTB2022NSCQ-MSX0826)National&Local Joint Engineering Research Center for mineral Salt Deep Utilization,Huaiyin Institute of Technology(No.SF202407)for financial support。
文摘The transition metal-catalyzed C–H activation have been considered as increasingly useful approach for installing new functional groups onto organic small molecules due to their high step-and atom-economy,the abundance of hydrocarbon compounds,and the potential for late-stage functionalization of complex organic molecules.The ortho-and meta-C-H activation and functionalization of aromatic compounds have been widely explored in recent years,however the distal para-C-H activation and functionalization has remained a significant challenge because of the difficulty in forming energetically favorable metallacyclic transition states.The utilization of appropriate directing groups or templates as well as the meticulous design of catalysts and ligands has proven to be effective in transition-metal-catalyzed remote para-C-H bonds activation and functionalization of aromatic compounds.This review aims to summarize the strategies for controlling para-selective C–H functionalization using the directing group,template engineering,and catalyst/ligand design under transition metals catalysis in recent years.
基金Department of Envirenmental Medicine, Bethune University of Medical Sciences
文摘The directing mechanisms of liquid directing agents of zeolite Y and zeolite L were studied by means of light transmission, ultracentrifugation, NMR, XRD and “cross-exchange” experiments. It was discovered that not only microcfystals of zeolites, but also cage structures of zeolites play the directing role for crystallization of zeolites.
文摘In this work,we show for the first time that high-silica zeolites(MFI,TON,MTT,and*MRE)could be synthesized from a combined strategy of both zeolite seeding and alcohol filling in the absence of organic structure-directing agents(OSDAs).High-silica ZSM-5 zeolites with Si/Al ratios ranging from 38 to 240(TF-Al-ZSM-5)could be synthesized via this route.The key to the success of this technique was the employment of an aluminosilicate precursor with a fully 4-coordinated aluminum species as the initial source,wherein the rearrangement and condensation of the silicate species,rather than the aluminate species,occurred during zeolite crystallization.In addition,heteroatoms,such as Fe and B,could be incorporated into the zeolite frameworks.Catalytic tests for the methanol-to-propylene(MTP)reaction exhibited good catalytic performance for TF-Al-ZSM-5,which was comparable to that of the aluminosilicate ZSM-5 zeolite synthesized with OSDAs.Hence,this method offers viable opportunities for the industrial production and catalytic application of high-silica zeolites in the future.
基金supported by the National Natural Science Foundation of China(Grant No.21802136)~~
文摘Zeolite synthesis in contemporary chemical industries is predominantly conducted using organic structure‐directing agents(OSDAs),which are chronically hazardous to humans and the environment.It is a growing trend to develop an eco‐friendly and nuisanceless OSDA for zeolite synthesis.Herein,choline is employed as a non‐toxic and green OSDA to synthesize high silica Y zeolite with SiO2/Al2O3 ratios of 6.5–6.8.The prepared Y zeolite samples exhibited outstanding(hydro)thermal stability at ultrahigh temperature owing to the higher SiO2/Al2O3 ratio.The XRF,SEM,29Si‐NMR and 13Na+results suggested that choline plays a structure‐directing role in the synthesis of Y zeolite,while the feed molar fraction of Na+is a crucial determinant for the framework SiO2/Al2O3 ratio and the crystal morphology.
基金the financial support from the National Natural Science Foundation of China(No.20973022 and No.11472048)the State Key Laboratory of Catalytic Materials and Reaction Engineering(RIPP,SINOPEC)(Serial No.33600000-14-ZC0607-0006)
文摘Zeolite FAU composites with a macro/meso-microporous hierarchical structure were hydrothermally synthesized using macro-mesoporous γ-Al_2O_3 monolith as the substrate by means of the liquid crystallization directing agent(LCDA) induced method. No template was needed throughout the synthesis processes. The structure and porosity of zeolite composites were analyzed by means of X-ray powder diffraction(XRD), scanning electron microscopy(SEM) and N_2adsorption-desorption isotherms. The results showed that the supported zeolite composites with varied zeolitic crystalline phases and different morphologies can be obtained by adjusting the crystallization parameters, such as the crystallization temperature, the composition and the alkalinity of the precursor solution. The presence of LCDA was defined as a determinant for synthesizing the zeolite composites. The mechanisms for formation of the hierarchically porous FAU zeolite composites in the LCDA induced synthesis process were discussed. The resulting monolithic zeolite with a trimodal-porous hierarchical structure shows potential applicability where facile diffusion is required.
基金financially supported by the National Natural Science Foundation of China(No.21861030)the Program for Young Talents of Science and Technology in Universities of Inner Mongolia Autonomous Region(No.NJYT-17-A22)。
文摘Reported herein is the first example of heterogeneous palladium catalyzed C(sp^(3))-H bonds arylation by a transient-ligand-directed strategy.Using supported palladium(metallic state) na nopariticles as catalyst,a wide range of aryl iodides undergo the coupling with various o-methylbenzaldehyde derivatives to assemble a library of highly selective and functionalized o-benzylbenzaldehydes.The stability of the catalyst was easily recovered four runs without significant loss of activity.The XPS analysis of the catalyst before and after reaction indicated that the reaction might be carried out by a catalytic cycle starting with Pd~0.
基金We thank the National Natural Science Fund of China(2016-Z0030)Natural Science Foundation of Liaoning Province(L2017 LQN008,L2019014).
文摘Silicoaluminophosphates SAPO-11 molecular sieves with small particle size and hierarchical pores were synthesized using the directing agent method.The effect of crystallization time on the particle structure,morphology,pore structure properties,and acid properties of SAPO-11 molecular sieves were investigated.Unlike the SAPO-11 molecular sieves synthesized with the conventional method,the results of XRD,SEM,BET and NH3-TPD analyses showed that the SAPO-11 molecular sieves synthesized by the directing agent method in a shorter crystallization time exhibited fine and uniform morphology.By increasing the crystallization time,the particle size of SAPO-11 molecular sieve was significantly reduced,and the mesoporous structure(intercrystalline pores)was formed.Furthermore,the external specific surface area and the total specific surface area reached 81.7 m^2/g and 192.0 m^2/g,respectively,which effectively reduced the pore mass transfer resistance and significantly increased the number of acid sites.The results of n-dodecane hydroisomerization revealed that the Pt/SAPO-11 prepared with the novel method exhibited higher catalytic activity and better hydroisomerization selectivity than that synthesized by the conventional hydrothermal method.Thus,the small particle molecular sieve showed a promising industrial application prospect to be used as catalyst support.
基金the NSFC(Nos.21372178 and 21572163)for financial supportsupported by the Scientific Innovation Program for College Students of Zhejiang Province(No. 2016R426061)
文摘In this review, we highlight the recent development in Ru（II）-catalyzed C-H activations under redox neutral conditions. After a brief introduction of the C-H activations with oxidizing direct group by different transition metal catalysts, the examples with Ru（ll） catalyst were classified and introduced according to different internal oxidants used in the system. The features of each methodology will be highlighted and the plausible reaction mechanism will be presented if available.
文摘Article 1 These regulations are formulated according to the rules of the State Law on foreign investment and the requirements of industrial policies to direct foreign investment, ensuring that it adapts to the programmes of China’s national economy and social development and protecting the legal rights and interests of investors.
文摘Non-surfactant diquaternary ammonium compounds have already been used for obtaining various zeolites in nanocrystalline form. However, facile synthesis of nanocrystals of mordenite (MOR) and beta (BEA) in this way remains challenging. Here, we present the direct synthesis of nanosized mordernite (MOR) and beta (BEA) zeolites with hexane- and p-xylene-bridged bis-methylpyrrolidinium, -methylpiperidinium and -DABCO diquats, which can be synthesized in a single step from common chemicals. Optimized recipes are presented for nanosized MOR (20–50 nm) and BEA (15–30 nm) zeolites. By investigating the solid products obtained during hydrothermal synthesis, the formation of nanocrystals can be linked to the strong interaction between diquat templates and aluminosilicate species during the induction stage, which limits the amorphous precursor particles to a size below 50 nm. Based on the textural and acidic properties, catalytic performance data are discussed evidencing the clear benefits of these nanosized zeolites over bulk reference samples in Friedel–Crafts reactions and n-alkane hydroconversion.
基金Early-Career Young Scientists and Technologists Project of Jiangxi Province(No.20244BCE52224)Jiangxi Provincial Natural Science Foundation(No.20252BAC200240)+1 种基金the Start-up Funds of Gannan Medical University(No.QD202406)National Key R&D Program of China(No.2023YFC3504100)for financial support。
文摘Organoboron compounds have garnered significant attention in the fields of organic synthesis,materials science,medicinal chemistry and fine chemicals.In the past few decades,transition metal-catalyzed C–H borylation has been developed rapidly and efficiently.In recent years,in order to explore eco-friendly,economical and efficient method for constructing C–B bond,chemists are dedicated to developing metalfree BX_(3)-mediated borylation.In this review,we present a systematic and comprehensive overview of the borylation driven by BX_(3) with different directing group auxiliary in the fields of organic synthesis and boron-containing organic materials since 2010,including(1)nitrogen directed C–H borylation,(2)oxygen directed C–H borylation,(3)sulfur directed C–H borylation and(4)phosphorus directed C–H borylation.The methods of borylation processes as well as the substance scopes,limits,and mechanisms of these routes are also discussed.
基金supported by the National Key Research and Development Program of China (2017YFB0702803)the National Natural Science Foundation of China (91545111, 91634201, 21773296, 21573282 and 21733013).
文摘Advanced solid-state NMR techniques,including PT-J-HMQC ^(27)Al/^(31)P double-resonance NMR,2D ^(31)P and 1H DQ-SQ MAS NMR experiments,have been used to study the structure-directing effect in the crystallization of the molecular sieve AlPO_(4) -11 synthesized by a solvent-free method.
文摘We report a computational study of the distribution of germanium ions among the double four-membered rings(D4Rs)in SCM-14 germanosilicate and the influence of a structure-directing agent(SDA)on the stability of the as-synthesized material.For the pure zeolite structure,the calculations suggested clustering of Ge ions and the formation of D4Rs populated entirely by Ge heteroatoms,while part of the D4Rs contain only Si as T-atoms.As a general trend,structures with more Ge–O–Ge bridges are more stable.
基金financially supported by the National Natural Science Foundation of China(21776311 and 22102215)Taishan Scholar Foundation(tspd20210308)+3 种基金the“111”Program of National College Disciplinary Innovation(B13031)Shandong Provincial Natural Science Foundation,China(ZR2019MB045 and ZR2019MB022)the National Key Technologies R&D Program of China,the Key Projects of Intergovernmental International Innovation Cooperation(2018YFE0118200)the Key Research and Development Project of Shandong province(2019JZZY010506).
文摘Rational design of organic structure-directing agents(OSDAs)is always regarded as a promising strategy to produce ZSM-48 with diverse configurations.However,to date,only OSDAs with alkyl and alkenyl groups have been employed to produce ^(*)MRE zeolites with different structures.Aromatic heterocyclic groups were rarely considered for the synthesis of ZSM-48 with a unique nanostructure.In this work,a triazine-based bolaform quaternary ammonium bifunctional template was designed for the first time to fabricate nanorod stacked hierarchical ZSM-48(NSH-ZSM-48).Nanorod-stacked ZSM-48 with different SiO_(2)/Al_(2)O_(3) ratios ranging from 100 to 500 was obtained via a conventional procedure,using the synthesized s-triazine based OSDA,and a reasonable formation mechanism was proposed based on geometrical matching.We also demonstrated that the ZSM-48 nanorods piled up to form an ordered bird’s nest-like hollow sphere configuration.The synthesized NSH-ZSM-48 possesses abundant mesopores and a high surface area,attributed to the SDA’s mesopore-forming and nanonrod’s stacking abilities.In contrast to conventional materials,1 wt%Pd/NSH-ZSM-48 experiences a dramatic increase in the conversion(3.59%)and selectivity(95.7%)of a cyclohexanol/cyclohexanone mixture in the selective oxidation of cyclohexane,which are higher than those for silicalite-1 and SBA-15 with the same loading(2.11%/66.1%and 1.76%/68.5%,respectively).
基金supported by Natural Science Foundation of Shanghai(No.23ZR1468700)the National Natural Science Foundation of China(No.22371211).
文摘Fluoroalkoxylated heterocycles,such as indoles,holds significant importance in pharmaceuticals and biology.Herein,we report a copper-mediated C4-H fluoroalkoxylation reaction of indoles via a transient directing group(TDG)strategy.This reaction exhibits excellent regioselectivity and broad functional group compatibility,offering a new approach for the synthesis of fluoroalkoxylated indoles.The reaction also represents an unprecedented example of 3d-transition metal-catalyzed C-H fluoroalkoxylation via a TDG strategy.
基金supported by the Excellent Going Abroad Expert's Training Program in Hebei Province(No.201940)S.L.was supported by the S&T Program of Hebei(No.22567607H)+3 种基金D.J.C.was supported by a National Health and Medical Research Council(Australia)Leadership Fellowship(2009564)ARC Centre of Excellence for Innovations in Peptide and Protein Science(CE200100012)L.Y.C.was supported by the CIPPS Parental Leave Momentum Initiative Grant(CE200100012)Advance Queensland Women's AcademicFoundation(WAF-6884942288).
文摘A nickel-catalyzed cascade C(sp^(2))–H alkynylation/hydroamination of unprotectedα-substituted benzylamines is achieved using a transient directing group(TDG).The combination of a TDG with a nickel catalyst significantly improves the overall step-and atom-economy.Studies have shown that the p-trifluoromethylbenzoic acid ligand is critical for achieving C(sp^(2))–H alkynylation and subsequent intramolecular hydroamination.This protocol provides a straightforward and efficient route for synthesizing substituted 1H-isoindoles,featuring good substrate compatibility.
基金Shandong Major Science and Technology Innovation Projects(2018CXGC0203)National Special Vegetable Industry Technology System Project(CARS-24-D-01)Shandong Agricultural University“Double-first-class”Collaborative Innovation Team of Horticultural Machinery Equipment(SYL2017XTTD07).
文摘Garlic planting requires a single seed with a scaly bud upward and vertically.In this study,an automatic garlic seed directing device was designed for auxiliary garlic seeding by utilizing a seed placed funnel,a correcting mechanism,and an automatic control system.Three factors influenced device performance:characteristics of garlic seeds,limited notch diameter of the seed placed funnel,and funnel taper of the seed placed funnel.The most optimal structural parameters of the seed placed funnel were determined via theoretical analysis.The research samples of Lanling and Jinxiang garlic were divided into three groups according to their respective sizes.3D design software(Solidworks)was used to simulate the above three factors and analyze their rules of action.The obtained simulation results demonstrated that the suitable range of funnel taper and limited notch diameter of seed placed funnel for the three groups of seed were from 40°to 60°and 6-8 mm,respectively.The bench test showed that when the funnel taper was 60°and the limited notch diameter was 10 mm,the success rates of the three groups’seeds in terms of scaly bud directing were 89.8%,91.6%and 96.6%respectively,which satisfied the agricultural requirements of garlic planting.Accordingly,the corresponding results may promote the study and improvement of garlic intelligent planting equipment.
基金Acknowledgement We thank National Basic Research Program of China （973 Program） （No. 2015CB856600）, the National Natural Science Foundation of China （Nos. 21632001, 21772002）, National Young Topnotch Talent Support Program, and Peking University Health Science Center （No. BMU20160541） for financial support of this work. We thank Bencong Zhu in this group for reproducing the results of 3b and 4f.
文摘Transition-metal catalyzed C--H functionalization of benzaldehydes is of great interest in organic synthesis. Herein, we developed a transient directing group assisted amidation of benzaldehydes catalyzed by rhodium catalyst. With the employment of 10 mol% of 4-trifluoromethyl aniline, the in situ generated imine groups as the directing group efficiently enable this transformation. By using this protocol, a wide range of benzaldehydes were efficiently converted into the corresponding N-（2-formylphenyl）benzamides utilizing dioxazolones as the nitrogen source.
基金Guangdong Basic and Applied Basic Research Foundation(2023B1515120050,2023A1515110529 and 2024A1515012454)Shenzhen Science and Technology Program(JCYJ20230807145759008 and KJZD20240903100206009).
文摘Acetolactate synthase(ALS)-targeting herbicides are among the most widely used weed-control chemicals globally.Mutations in the ALS gene can confer herbicide resistance in crops,thereby allowing selective elimination of weeds without harming crops.Herbicide-resistant ALS alleles were initially discovered in weeds and subsequently developed through artificial mutagenesis techniques.With the advancement of CRISPR/Cas technologies,various genome-editing tools are now available to introduce these resistant alleles,as well as novel variants,into diverse crop species.Moreover,emerging methodologies,such as directed evolution,enable the generation and screening of large populations of random ALS mutants.Consequently,ALS has become one of the most extensively targeted genes in plant gene evolution.This paper provides a comprehensive overview of both conventional and recently developed strategies for ALS evolution,with particular emphasis on CRISPR/Cas-based genome editing and directed evolution.Future perspectives on technological application are also discussed.By advancing our understanding of herbicide-resistant ALS allele development for crop improvement,these methodologies may also pave the way for their application to the evolution of other agronomically important genes.
