When zero-valent iron(ZVI)is prepared and applied under neutral conditions,it is easy to form oxides or hydroxides on its surface,which hinders the electron release of ZVI.To this end,a nucleophile was introduced into...When zero-valent iron(ZVI)is prepared and applied under neutral conditions,it is easy to form oxides or hydroxides on its surface,which hinders the electron release of ZVI.To this end,a nucleophile was introduced into the ZVI system to inhibit the precipitation of iron ions,improve the conductivity of the solution,and promote the removal efficiency of electrophilic functional groups in organic compounds.In this study,the addition of nucleophiles such as ethylenediamine,methylamine and dimethylamine to the ZVI/H_(2)O_(2)system resulted in an enhanced removal efficiency of tetracycline(TC)under neutral condition,while electrophiles such as EDTA-2Na and oxalic acid dihydrate impeded the removal of TC.Experimental results demonstrated that the presence of nucleophiles could effectively promote the release of iron ions and increase the proportion of ferrous in both aqueous solution and solid surface of ZVI.Experimental and theoretical calculation results revealed that the electrophilic functional group was eliminated in the TC molecule,and the toxicity of the treated solution was reduced significantly.Overall,this work provides a selection of the conditions and pollutants applicable to ZVI under neutral pH conditions.展开更多
A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead o...A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with a piperazine's derivatives, which proceeds with very high regioselectivity.展开更多
A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine＇s derivatives were nucleophiles in this reaction. The yields of the produ...A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine＇s derivatives were nucleophiles in this reaction. The yields of the products 2a-f are good and the regioselectivity are excellent.展开更多
The asymmetric desymmetrization of cyclic anhydrides via the addition of carbon-based nucleophiles has been the focus of considerable levels of interest because it leads to optically active products. Over the past 20 ...The asymmetric desymmetrization of cyclic anhydrides via the addition of carbon-based nucleophiles has been the focus of considerable levels of interest because it leads to optically active products. Over the past 20 years, a variety of different catalytic asymmetric alkylation reactions have been developed for the desymmetrization of cyclic anhydrides using different metal reagents as nucleophiles and using chiral ligands. The purpose of this review is to provide an overview of significant developments in this field. ~ 2013 Fen-Er Chen. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.展开更多
We have demonstrated the direct substitution of 9H-xanthen-9-ol with different nucleophilic reagents such as thiazoles, triazoles, tetrazoles, hydrazines and hydrazinecarboxamides in good to high yields. This reaction...We have demonstrated the direct substitution of 9H-xanthen-9-ol with different nucleophilic reagents such as thiazoles, triazoles, tetrazoles, hydrazines and hydrazinecarboxamides in good to high yields. This reaction catalyzed by ferric hydro- gensulfate as a heterogeneous acid catalyst in ethanol through SN1 type reaction of pyrylium with a nucleophilic reagent afforded the heterocycle- and aromatic-N-substituted xanthene derivatives as simple marked molecules in short reaction times.展开更多
A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones w...A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.展开更多
P-stereogenic compounds play pivotal roles in natural products,pharmaceuticals,bioactive molecules,and catalysts/ligands,making their synthesis a highly researched area.Current studies have predominantly concentrated ...P-stereogenic compounds play pivotal roles in natural products,pharmaceuticals,bioactive molecules,and catalysts/ligands,making their synthesis a highly researched area.Current studies have predominantly concentrated on fully carbon-substituted P-stereogenic species,despite the fact that many therapeutically relevant compounds feature P-O,P-N,or P-S bonds.The catalytic and stereoselective nucleophilic substitution at the P-center is acknowledged as a highly efficient and straightforward approach for constructing high-value P-stereogenic compounds,offering significant potential for further development.This review provides an overview of advancements in the construction of P-stereogenic centers based on Pcentered nucleophilic substitution,highlighting key challenges,breakthroughs,and future opportunities in the field.展开更多
Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free m...Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free method by a complexmediated nucleophilic aromatic substitution of aryl nitriles with amines.The method can lead to rich D-A type aggregation-induced emission luminogens(AIEgens)with tunable properties.They emit from deep-blue to yellow-green and possess high photoluminescence quantum yields up to 70.5%in the aggregate state.Interestingly,the suppression of intramolecular flapping is proved to play an indispensable role in the AIE behavior,which is different from the mechanism met in other AIEgens.Moreover,the biocompatible AIEgens possess specific staining of lipid droplets in HeLa cells and the superiority of identifying fatty liver over traditional Oil Red O staining is exhibited.展开更多
Herein,a metal-free electrochemical demethoxyl-cyanation of methoxyarenes via aromatic nucleophilic substitution(S_(N)Ar) using TMSCN as a cheap cyanide source under mild conditions has been presented.This transformat...Herein,a metal-free electrochemical demethoxyl-cyanation of methoxyarenes via aromatic nucleophilic substitution(S_(N)Ar) using TMSCN as a cheap cyanide source under mild conditions has been presented.This transformation utilizes commercially available reagents,cheap electrodes,and simple equipment.Diverse aryl nitriles were successfully obtained in a direct and efficient way with broad substrate scope,excellent functional group tolerance,and selective C-O bond cleavage.Furthermore,late-stage modification of biorelevant compounds and gram-scale synthesis highlighted the potential application of the strategy.Mechanistic investigations suggest that the arene cation radical was considered as the key intermediate for the transformation,and undergoing the followed S_(N)Ar process.展开更多
Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding pro...Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding proton trap 2,6-di-tert-butylpyridine(DTBP),and the controlled initiation of DCC was confirmed by ^(1)H nuclear magnetic resonance(^(1)H-NMR)spectroscopy and matrix-assisted laser desorption ionization time-offlight mass(MALDI-TOF-MS)spectrometry.The polymerization kinetics were analyzed to for optimizing the polymerization rate.Allyl-telechelic PSTOs(allyl-PSTO-allyl)with molecular weight(Mn)range of 3540–7800 g/mol and narrow molecular weight dispersity(Mw/Mn)about 1.25 were prepared through nucleophilic substitution with allyltrimethylsilane(ATMS)at approximately 40%monomer conversion.The experimental results indicate that the substitution efficiency of ATMS increased with higher ATMS concentration,temperature,and extended reaction time.Nearly unity ally-functionality for allyl-PSTO-allyl was achieved by adding sufficient SnCl_(4) prior to the substitution.展开更多
Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge...Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge under mild conditions.And their complex multi-step transformations may also hinder mechanistic understanding.Herein,we perform theoretical calculations and experimental studies to explore the C_(sp3)-H bonds activation and acylation mechanisms of toluene/thioether using the relatively weak base LDA.A synergistic"main and auxiliary"model was revealed involving dual lithium metal by LDA dimers,and the aryl dilithium species as an intermediate base can facilitate C_(sp3)-H activation.This model not only aids in understanding the acidity of unactivated C_(sp3)-H bonds and the nucleophilicity of their conjugate bases for their kinetic control through cooperative interactions,but also predicts unusual kinetic isotope effects(KIE)for newly designed 2-(methylthio)naphthalene that are experimentally validated.This research is expected to provide a crucial scenario for the cleavage and transformation of unactivated C_(sp3)-H bonds and the development of new functionalities for alkali metal reagents.展开更多
Condensation of methyl 7-methylcoumarin-4-acetate(2)with primary amines and with an- thranilic acid gave 7-methyl-2-oxo-N-aryl-2H-[1]-benzopyran-4--acetamide(4a—d)and(7),respectively. Compound 7 underwent cyclization...Condensation of methyl 7-methylcoumarin-4-acetate(2)with primary amines and with an- thranilic acid gave 7-methyl-2-oxo-N-aryl-2H-[1]-benzopyran-4--acetamide(4a—d)and(7),respectively. Compound 7 underwent cyclization to give 2-(7-methyl-2-oxo-2H-[1]-benzopyran-4-yl)-methyl-4H-3,1- benzoxazin-4-one(3).The reaction of 3 with aromatic amines gave the corresponding quinazolone derivatives 5 which tautomerises to the thermodynamically more stable isomer 6,whereas its reaction with Grignard reagents and aromatic aldehydes gave 8a,8b,and 9a,9b,respectively.展开更多
The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its...The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.展开更多
Seawater splitting into hydrogen,a promising technology,is seriously limited by the durability and tolerance of electrocatalysts for chlorine ions in seawater at large current densities due to chloride oxidation and c...Seawater splitting into hydrogen,a promising technology,is seriously limited by the durability and tolerance of electrocatalysts for chlorine ions in seawater at large current densities due to chloride oxidation and corrosion.Here,we present a robust and weak-nucleophilicity nickel-iron hydroxide electrocatalyst with excellent selectivity for oxygen evolution and an inert response for chlorine ion oxidation which are key and highly desired for efficient seawater electrolysis.Such a weak-nucleophilicity electrocatalyst can well match with strong-nucleophilicity OH-compared with the weak-nucleophilicity Cl^(-),resultantly,the oxidation of OH-in electrolyte can be more easily achieved relative to chlorine ion oxidation,confirmed by ethylenediaminetetraacetic acid disodium probing test.Further,no strongly corrosive hypochlorite is produced when the operating voltage reaches about 2.1 V vs.RHE,a potential that is far beyond the thermodynamic potential of chlorine ion oxidatio n.This concept and approach to reasonably designing weaknucleophilicity electrocatalysts that can greatly avoid chlorine ion oxidation under alkaline seawater environments can push forward the seawater electrolysis technology and also accelerate the development of green hydrogen technique.展开更多
Zincophilic property and high electrical conductivity are both very important parameters to design novel Zn anode for aqueous Zn-ion batteries(AZIBs).However,single material is difficult to exhibit zincophilic propert...Zincophilic property and high electrical conductivity are both very important parameters to design novel Zn anode for aqueous Zn-ion batteries(AZIBs).However,single material is difficult to exhibit zincophilic property and high electrical conductivity at the same time.Herein,originating from theoretical calculation,a zincophilic particle regulation strategy is proposed to address these limitations and carbon coated Na_(3)V_(2)(PO_(4))_(3)is taken as an example to be a protective layer on zinc metal(NVPC@Zn).Na_(3)V_(2)(PO_(4))_(3)(NVP)is a common cathode material for Zn-ion batteries,which is zincophilic.Carbon materials not only offer an electron pathway to help Zn deposition onto NVPC surface,but also enhance the zinc nucleophilicity of Na_(3)V_(2)(PO_(4))_(3).Hence,this hybrid coating layer can tune zinc deposition and resist side reactions such as hydrogen generation and Zn metal corrosion.Experimentally,a symmetrical battery with NVPC@Zn electrode displays highly reversible plating/stripping behavior with a long cycle lifespan over 1800 h at2 mA cm^(-2),much better than carbon and Na_(3)V_(2)(PO_(4))_(3)solely modified Zn electrodes.When the Na_(3)V_(2)(PO_(4))_(3)is replaced with zincophobic Al2O3or zincophilic V2O3,the stability of the modified zinc anodes is also prolonged.This strategy expands the option of zincophilic materials and provides a general and effective way to stabilize the Zn electrode.展开更多
Nucleophilic phosphine and amine catalyst-switched chemodivergent[4+1]and[3+3]annulations of allenyl imides andβ,γ-enones have been developed,furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives...Nucleophilic phosphine and amine catalyst-switched chemodivergent[4+1]and[3+3]annulations of allenyl imides andβ,γ-enones have been developed,furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives in moderate to excellent yields.Two plausible reaction mechanisms involving two different ketene intermediates have been proposed to explain the observed chemoselectivity.Moreover,by virtue of theα,β-enone substructure of the[4+1]adducts,1,3-dipolar cycloaddition of nitrile imines has been studied in one-pot to provide various fused pyrazoline derivatives.展开更多
An efficient method for the synthesis of α-phenylcinnamates via silver catalyzed C—C bond activation reaction of cyclopropenone and alcohol was developed.This protocol features a simple reaction system,specific regi...An efficient method for the synthesis of α-phenylcinnamates via silver catalyzed C—C bond activation reaction of cyclopropenone and alcohol was developed.This protocol features a simple reaction system,specific regioselectivity,good functional group compatibility and good yields.It is of great significance for the later modification of natural products.展开更多
The propargylation of various nucleophiles including indoles,phenol,anisole,enoxysilanes,and alcohols was rapidly achieved using catalytic copper(Ⅱ)triflate.The reaction conditions are mild,allowing for quick reactio...The propargylation of various nucleophiles including indoles,phenol,anisole,enoxysilanes,and alcohols was rapidly achieved using catalytic copper(Ⅱ)triflate.The reaction conditions are mild,allowing for quick reactions in an undried solvent and under atmospheric air.The desired products are obtained with good yields.展开更多
We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of d...We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.展开更多
Lithium sulfur batteries(LSBs)show great promise as next-generation batteries due to their high energy density.However,commercialization is hindered by limited cycle life,fast capacity decay and poor sulfur utilizatio...Lithium sulfur batteries(LSBs)show great promise as next-generation batteries due to their high energy density.However,commercialization is hindered by limited cycle life,fast capacity decay and poor sulfur utilization,primarily due to the intricate phase evolution during battery operation and insulating characteristics of sulfur,leading to uncontrollable sulfur and polysulfide distribution and inefficient conversion kinetics.Therefore,the incorporation of metal and covalent organic frameworks(MOFs and COFs)has been widely employed in LSBs to serve as hosts,enabling the regulation of conversion and diffusion behavior of vip species,including lithium ions,sulfur and polysulfides,within their well-defined nanosized cavities.Nevertheless,pristine frameworks often fail to meet the requisite standards,and framework functionalization offers unique opportunities to tailor desired attributes and facilitate selective host-vip interactions in LSBs.However,a thorough understanding on how to precisely customize the nano-channels with functional groups to promote such interactions remains largely unexplored.In this review,we provide a systematic discussion on how the grafting of functional groups containing various active sites can play a role in host-vip chemistry,and focus on the latest advancements in engineering functionalized MOFs and COFs as charged-species regulators to tackle the problems causing poor LSB electrochemical performance.The concepts of electrophilic and nucleophilic effects are proposed,uncovering the mechanisms of framework functionalization in LSBs and serving as guidance for future developments.展开更多
基金financial support from Sichuan Science and Technology Program(No.2023NSFSC0345)the Fundamental Research Funds for the Central Universities(Southwest Minzu University,No.ZYN2022002)+1 种基金the Innovation Scientific Research Program for Graduates of Southwest Minzu University(Southwest Minzu University,No.3300222156)the China Scholarship Council(No.202008510077)。
文摘When zero-valent iron(ZVI)is prepared and applied under neutral conditions,it is easy to form oxides or hydroxides on its surface,which hinders the electron release of ZVI.To this end,a nucleophile was introduced into the ZVI system to inhibit the precipitation of iron ions,improve the conductivity of the solution,and promote the removal efficiency of electrophilic functional groups in organic compounds.In this study,the addition of nucleophiles such as ethylenediamine,methylamine and dimethylamine to the ZVI/H_(2)O_(2)system resulted in an enhanced removal efficiency of tetracycline(TC)under neutral condition,while electrophiles such as EDTA-2Na and oxalic acid dihydrate impeded the removal of TC.Experimental results demonstrated that the presence of nucleophiles could effectively promote the release of iron ions and increase the proportion of ferrous in both aqueous solution and solid surface of ZVI.Experimental and theoretical calculation results revealed that the electrophilic functional group was eliminated in the TC molecule,and the toxicity of the treated solution was reduced significantly.Overall,this work provides a selection of the conditions and pollutants applicable to ZVI under neutral pH conditions.
文摘A new rhodium catalyzed ring opening reaction of oxabenzonorbornadienes and its derivatives was described. This reaction forms a new carbon-nitrogen bond via an intermolecular allylic displacement of the bridgehead oxygen with a piperazine's derivatives, which proceeds with very high regioselectivity.
文摘A rhodium-catalyzed ring opening reaction of N-Boc-azabenzonorbornadiene with heteroatom nucleophiles was described. Piperidine and piperazine＇s derivatives were nucleophiles in this reaction. The yields of the products 2a-f are good and the regioselectivity are excellent.
文摘The asymmetric desymmetrization of cyclic anhydrides via the addition of carbon-based nucleophiles has been the focus of considerable levels of interest because it leads to optically active products. Over the past 20 years, a variety of different catalytic asymmetric alkylation reactions have been developed for the desymmetrization of cyclic anhydrides using different metal reagents as nucleophiles and using chiral ligands. The purpose of this review is to provide an overview of significant developments in this field. ~ 2013 Fen-Er Chen. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.
基金Department of Chemistry,Ferdowsi University of Mashhad,for financial support(49-P-24-01- 89)
文摘We have demonstrated the direct substitution of 9H-xanthen-9-ol with different nucleophilic reagents such as thiazoles, triazoles, tetrazoles, hydrazines and hydrazinecarboxamides in good to high yields. This reaction catalyzed by ferric hydro- gensulfate as a heterogeneous acid catalyst in ethanol through SN1 type reaction of pyrylium with a nucleophilic reagent afforded the heterocycle- and aromatic-N-substituted xanthene derivatives as simple marked molecules in short reaction times.
文摘A new gold self-relay catalytic annulation/nucleophilic substitution cascade of 1,3-enyne acetates with cyclic ether acetals is reported,enabling highly diastereoselective access to cyclic etherified cyclopentenones with cyclic quaternary centers in moderate to good yields and>19∶1 dr.This catalysis enables the direct construction of two types of carboncyclic skeletons by adjusting the olefin types of 1,3-enyne acetates.When 1,3-enyne acetates bearing a cyclic alkene unit were used,5~6 fused bicarbocyclic products were diastereoselectively synthesized,whereas the reaction of acyclic 1,3-enyne acetates resulted in five-memebered carbocyclic framework.Notably,cyclic ether acetals are commonly used as protecting groups in traditional multistep organic syntheses,and in this reaction,such reagents serve as electrophilic cyclic ether precursors,achieving new uses for old reagents.The current method demonstrates good functional group compatibility,a broad substrate scope and high diastereoselectivity,providing a new synthetic strategy toward functionalized cyclopentenones.
基金financial support from the National Natural Science Foundation of China(Nos.22171187 and 22001173)the Project of Department of Education of Guangdong Province(No.2020KTSCX116)+3 种基金the Shenzhen Science and Technology Foundation(Nos.20200812202943001 and KQJSCX20180328100401788)Frontiers Science Center for Asymmetric Synthesis and Medicinal Molecules,Department of Education,Guizhou Province(No.Qianjiaohe KY(2020)004)the Central Government Guides Local Science and Technology Development Fund Projects(Nos.Qiankehezhongyindi(2024)007,(2023)001)Singapore National Research Foundation under its NRF Competitive Research Program(No.NRFCRP22–2019–0002)。
文摘P-stereogenic compounds play pivotal roles in natural products,pharmaceuticals,bioactive molecules,and catalysts/ligands,making their synthesis a highly researched area.Current studies have predominantly concentrated on fully carbon-substituted P-stereogenic species,despite the fact that many therapeutically relevant compounds feature P-O,P-N,or P-S bonds.The catalytic and stereoselective nucleophilic substitution at the P-center is acknowledged as a highly efficient and straightforward approach for constructing high-value P-stereogenic compounds,offering significant potential for further development.This review provides an overview of advancements in the construction of P-stereogenic centers based on Pcentered nucleophilic substitution,highlighting key challenges,breakthroughs,and future opportunities in the field.
基金supported by the National Natural Science Foundation of China(22275072 and 62105184)the Natural Science Foundation of Guangdong Province(2020A1515010622)+1 种基金the Project of Science and Technology of Guangzhou(2024A04J3712)the Teli Young Scholar Program of Beijing Institute of Technology.
文摘Donor-acceptor(D-A)compounds are particularly important in optoelectronic and biological applications.However,they are normally synthesized in the presence of transition metal catalysts.Herein,we report a metal-free method by a complexmediated nucleophilic aromatic substitution of aryl nitriles with amines.The method can lead to rich D-A type aggregation-induced emission luminogens(AIEgens)with tunable properties.They emit from deep-blue to yellow-green and possess high photoluminescence quantum yields up to 70.5%in the aggregate state.Interestingly,the suppression of intramolecular flapping is proved to play an indispensable role in the AIE behavior,which is different from the mechanism met in other AIEgens.Moreover,the biocompatible AIEgens possess specific staining of lipid droplets in HeLa cells and the superiority of identifying fatty liver over traditional Oil Red O staining is exhibited.
基金Financial support from National Key R&D Program of China(No.2023YFA1507203)National Natural Science Foundation of China(Nos.22371149,22188101)+2 种基金the Fundamental Research Funds for the Central Universities(No.63224098)Frontiers Science Center for New Organic Matter,Nankai University(No.63181206)the Haihe Laboratory of Sustainable Chemical Transformations for financial support。
文摘Herein,a metal-free electrochemical demethoxyl-cyanation of methoxyarenes via aromatic nucleophilic substitution(S_(N)Ar) using TMSCN as a cheap cyanide source under mild conditions has been presented.This transformation utilizes commercially available reagents,cheap electrodes,and simple equipment.Diverse aryl nitriles were successfully obtained in a direct and efficient way with broad substrate scope,excellent functional group tolerance,and selective C-O bond cleavage.Furthermore,late-stage modification of biorelevant compounds and gram-scale synthesis highlighted the potential application of the strategy.Mechanistic investigations suggest that the arene cation radical was considered as the key intermediate for the transformation,and undergoing the followed S_(N)Ar process.
基金financially supported by the National Natural Science Foundation of China(No.52373011)。
文摘Living cationic polymerization of 4-acetoxystyrene(STO)was conducted in CH_(2)Cl_(2) at-15℃ using a dicumyl chloride(DCC)/SnCl_(4)/nBu_(4)NBr initiating system.Impurity moisture initiation was inhibited by adding proton trap 2,6-di-tert-butylpyridine(DTBP),and the controlled initiation of DCC was confirmed by ^(1)H nuclear magnetic resonance(^(1)H-NMR)spectroscopy and matrix-assisted laser desorption ionization time-offlight mass(MALDI-TOF-MS)spectrometry.The polymerization kinetics were analyzed to for optimizing the polymerization rate.Allyl-telechelic PSTOs(allyl-PSTO-allyl)with molecular weight(Mn)range of 3540–7800 g/mol and narrow molecular weight dispersity(Mw/Mn)about 1.25 were prepared through nucleophilic substitution with allyltrimethylsilane(ATMS)at approximately 40%monomer conversion.The experimental results indicate that the substitution efficiency of ATMS increased with higher ATMS concentration,temperature,and extended reaction time.Nearly unity ally-functionality for allyl-PSTO-allyl was achieved by adding sufficient SnCl_(4) prior to the substitution.
基金the National Key Research and Development Program of China(No.2021YFA1500100)the National Natural Science Foundation of China(Nos.92156017 and 21890722)+1 种基金“Frontiers Science Center for New Organic Matter”,Nankai University(No.63181206)Haihe Laboratory of Sustainable Chemical Transformation of Tianjin(No.24HHWCSS00019)for generous financial support。
文摘Mechanistic studies of the cleavage and transformation of unactivated C_(sp3)-H bonds are a significant field of chemistry.Overcoming the inherent low acidity of C-H bonds to activate the inert substrates is challenge under mild conditions.And their complex multi-step transformations may also hinder mechanistic understanding.Herein,we perform theoretical calculations and experimental studies to explore the C_(sp3)-H bonds activation and acylation mechanisms of toluene/thioether using the relatively weak base LDA.A synergistic"main and auxiliary"model was revealed involving dual lithium metal by LDA dimers,and the aryl dilithium species as an intermediate base can facilitate C_(sp3)-H activation.This model not only aids in understanding the acidity of unactivated C_(sp3)-H bonds and the nucleophilicity of their conjugate bases for their kinetic control through cooperative interactions,but also predicts unusual kinetic isotope effects(KIE)for newly designed 2-(methylthio)naphthalene that are experimentally validated.This research is expected to provide a crucial scenario for the cleavage and transformation of unactivated C_(sp3)-H bonds and the development of new functionalities for alkali metal reagents.
文摘Condensation of methyl 7-methylcoumarin-4-acetate(2)with primary amines and with an- thranilic acid gave 7-methyl-2-oxo-N-aryl-2H-[1]-benzopyran-4--acetamide(4a—d)and(7),respectively. Compound 7 underwent cyclization to give 2-(7-methyl-2-oxo-2H-[1]-benzopyran-4-yl)-methyl-4H-3,1- benzoxazin-4-one(3).The reaction of 3 with aromatic amines gave the corresponding quinazolone derivatives 5 which tautomerises to the thermodynamically more stable isomer 6,whereas its reaction with Grignard reagents and aromatic aldehydes gave 8a,8b,and 9a,9b,respectively.
文摘The reactions of 1,3-dinitro-2-chloro-5-trifluorotoluene(DNCTT)(1)and its bridged com- pounds with bidentate nucleophiles have been investigated.Primary or secondary diamines and diethylene glycol react with 1 and its bridged derivatives by replacing the substituent grouppara to CF_3, whereas ethanedithiol reacts either by replacing the substituent group para to CF_3 or by displacing both groups and a nitro group.The results have been rationalized in terms of electronic effects and nucleophilicity of the nucleophiles.
基金supported by the National Natural Science Foundation of China(NSFC,No.22078052)the Fundamental Research Funds for the Central Universities(DUT22ZD207,DUT22LAB612)。
文摘Seawater splitting into hydrogen,a promising technology,is seriously limited by the durability and tolerance of electrocatalysts for chlorine ions in seawater at large current densities due to chloride oxidation and corrosion.Here,we present a robust and weak-nucleophilicity nickel-iron hydroxide electrocatalyst with excellent selectivity for oxygen evolution and an inert response for chlorine ion oxidation which are key and highly desired for efficient seawater electrolysis.Such a weak-nucleophilicity electrocatalyst can well match with strong-nucleophilicity OH-compared with the weak-nucleophilicity Cl^(-),resultantly,the oxidation of OH-in electrolyte can be more easily achieved relative to chlorine ion oxidation,confirmed by ethylenediaminetetraacetic acid disodium probing test.Further,no strongly corrosive hypochlorite is produced when the operating voltage reaches about 2.1 V vs.RHE,a potential that is far beyond the thermodynamic potential of chlorine ion oxidatio n.This concept and approach to reasonably designing weaknucleophilicity electrocatalysts that can greatly avoid chlorine ion oxidation under alkaline seawater environments can push forward the seawater electrolysis technology and also accelerate the development of green hydrogen technique.
基金financially supported by the National Key Research and Development Program of China(2022YFB3803600)the Fundamental Research Funds for the Central Universities(30106200463 and CCNU22CJ017)+1 种基金the National Natural Science Foundation of China(U20A20246)the Graduate Education Innovation Grant from Central China Normal University,China(20210407032)。
文摘Zincophilic property and high electrical conductivity are both very important parameters to design novel Zn anode for aqueous Zn-ion batteries(AZIBs).However,single material is difficult to exhibit zincophilic property and high electrical conductivity at the same time.Herein,originating from theoretical calculation,a zincophilic particle regulation strategy is proposed to address these limitations and carbon coated Na_(3)V_(2)(PO_(4))_(3)is taken as an example to be a protective layer on zinc metal(NVPC@Zn).Na_(3)V_(2)(PO_(4))_(3)(NVP)is a common cathode material for Zn-ion batteries,which is zincophilic.Carbon materials not only offer an electron pathway to help Zn deposition onto NVPC surface,but also enhance the zinc nucleophilicity of Na_(3)V_(2)(PO_(4))_(3).Hence,this hybrid coating layer can tune zinc deposition and resist side reactions such as hydrogen generation and Zn metal corrosion.Experimentally,a symmetrical battery with NVPC@Zn electrode displays highly reversible plating/stripping behavior with a long cycle lifespan over 1800 h at2 mA cm^(-2),much better than carbon and Na_(3)V_(2)(PO_(4))_(3)solely modified Zn electrodes.When the Na_(3)V_(2)(PO_(4))_(3)is replaced with zincophobic Al2O3or zincophilic V2O3,the stability of the modified zinc anodes is also prolonged.This strategy expands the option of zincophilic materials and provides a general and effective way to stabilize the Zn electrode.
基金the financial support for this investigation from the National Natural Science Foundation of China(No.22072111the Fundamental Research Funds for the Central Universities(No.2023IVA055).
文摘Nucleophilic phosphine and amine catalyst-switched chemodivergent[4+1]and[3+3]annulations of allenyl imides andβ,γ-enones have been developed,furnishing highly substituted 2-cyclopentenone and 2-pyranone derivatives in moderate to excellent yields.Two plausible reaction mechanisms involving two different ketene intermediates have been proposed to explain the observed chemoselectivity.Moreover,by virtue of theα,β-enone substructure of the[4+1]adducts,1,3-dipolar cycloaddition of nitrile imines has been studied in one-pot to provide various fused pyrazoline derivatives.
基金Project supported by the National Natural Science Foundation of China(No.21702160)the State Key Laboratory of Fine Chemicals,Dalian University of Technology(No.KF2311)。
文摘An efficient method for the synthesis of α-phenylcinnamates via silver catalyzed C—C bond activation reaction of cyclopropenone and alcohol was developed.This protocol features a simple reaction system,specific regioselectivity,good functional group compatibility and good yields.It is of great significance for the later modification of natural products.
文摘The propargylation of various nucleophiles including indoles,phenol,anisole,enoxysilanes,and alcohols was rapidly achieved using catalytic copper(Ⅱ)triflate.The reaction conditions are mild,allowing for quick reactions in an undried solvent and under atmospheric air.The desired products are obtained with good yields.
文摘We analysed the photooxidation reaction in the electro-(1O2) and nucleophilic (O2•−) reaction of 2-pyridone azo derivatives. First, we calculated the energy (enthalpies) of tautomers formation, which is a measure of durability and the probability of their formation. We performed the light fastness calculations of the monoazopyridone dyes. Using the semi-empirical methods of quantum chemistry AM1 and PM3, the reactivity indicators of superdelocalisability (SrE(N)) and the electron density distribution in ground state on the highest occupied HOMO orbital and the lowest unoccupied excited state LUMO in 2-pyridone phenylazo derivatives were calculated. Superdelocalisability coefficients enable the stability to oxidising agents of various chemical molecules depending on the tautomeric forms in which they may occur. The results of the electron density calculations at the HOMO and LUMO boundary orbitals allow to determine the tendency to electrophilic attack with singlet oxygen 1O2 or nucleophilic attack of the superoxide anion O2•−on a specific atom in the molecule. The structure of the dyes was optimised with MM+, MD and AM1 or PM3 until a constant energy value was achieved with a convergence criterion of 0.01 kcal/mol.
基金supported by the Singapore Ministry of Education,and the National Research Foundation(NRF)for research conducted at the National University of Singapore(CRP NRF-CRP26-2021-0003).
文摘Lithium sulfur batteries(LSBs)show great promise as next-generation batteries due to their high energy density.However,commercialization is hindered by limited cycle life,fast capacity decay and poor sulfur utilization,primarily due to the intricate phase evolution during battery operation and insulating characteristics of sulfur,leading to uncontrollable sulfur and polysulfide distribution and inefficient conversion kinetics.Therefore,the incorporation of metal and covalent organic frameworks(MOFs and COFs)has been widely employed in LSBs to serve as hosts,enabling the regulation of conversion and diffusion behavior of vip species,including lithium ions,sulfur and polysulfides,within their well-defined nanosized cavities.Nevertheless,pristine frameworks often fail to meet the requisite standards,and framework functionalization offers unique opportunities to tailor desired attributes and facilitate selective host-vip interactions in LSBs.However,a thorough understanding on how to precisely customize the nano-channels with functional groups to promote such interactions remains largely unexplored.In this review,we provide a systematic discussion on how the grafting of functional groups containing various active sites can play a role in host-vip chemistry,and focus on the latest advancements in engineering functionalized MOFs and COFs as charged-species regulators to tackle the problems causing poor LSB electrochemical performance.The concepts of electrophilic and nucleophilic effects are proposed,uncovering the mechanisms of framework functionalization in LSBs and serving as guidance for future developments.
