Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.De...Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.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
Based on the density functional theory, we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons. ...Based on the density functional theory, we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons. Descriptors including global softness, Fukui function, local softness and local mulliken charge were calculated at SVWN/DN＊ level of DFT with PC Spartan Pro. Nucleophilicity and basicity of 28 selected compounds were classified based on intensity. BP algorithm of artificial neural network （ANN） was employed to study the relationship between the descriptors and nucleophilicity/basicity. Cross-validation was carried out to avoid the over-fitting in training of ANN. A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons. The results show that the prediction based on the network matches with the experimental results well. The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity. The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.展开更多
High nucleophilicity of formate toward polyhalofluoroalkenes under acidic condition is described. This reaction offers a convenient method for the synthesis of E-α,β-unsaturated polyhalofluorocarboxylic acids.
Pseudomonas aeruginosa is an opportunistic pathogen responsible for severe nosocomial infections.This multidrug-resistant bacterium can cause pneumonia and cystic fibrosis,both of which are associated with high morbid...Pseudomonas aeruginosa is an opportunistic pathogen responsible for severe nosocomial infections.This multidrug-resistant bacterium can cause pneumonia and cystic fibrosis,both of which are associated with high morbidity and mortality rates.The lipopolysaccharide of P.aeruginosa serves as an attractive target for the development of effective glycoconjugate vaccines.In this article,we report the first chemical synthesis of the highly challenging tetrasaccharide repeating unit of the P.aeruginosa serotype O3 O-antigen using a two-directional[1+(2+1)]glycosylation strategy.The synthesis is particularly challenging due to the poor nucleophilicity of the axial C4 hydroxyl group of l-galactose and the steric hindrance imposed by the 3S-hydroxybutyryl(Hb)chain.Furthermore,the presence of an acetyl group at the ortho position relative to the glycosylation site on l-galactose can lead to undesirable acetyl migration.Additionally,it is noteworthy that the selective removal of a 2-naphthylmethyl ether(Nap)during the late stages of synthesis,particularly in the presence of multiple benzyl groups,can be somewhat challenging to predict.Through the careful selection of synthetic strategies,building blocks,and optimized reaction conditions,we achieved the stereoselective glycosylations,selective oxidation of primary alcohols,remarkable enhancement of acceptor activity,and efficient introduction of the 3S-Hb group.The synthetic methodology presented in this work serves as a valuable reference for the preparation of structurally related oligosaccharides.By incorporating an aminopropyl linker,the target tetrasaccharide facilitates glycan microarray preparation and in vivo immunological assessments,thereby accelerating progress toward a synthetic glycoconjugate vaccine for P.aeruginosa.展开更多
High-nickel cathode,LiNi0.8Co0.1Mn0.1O_(2)(NCM811),and sulfide-solid electrolyte are a promising combination for all-solid-state lithium batteries(ASSLBs).However,this combination faces the issue of interfacial instab...High-nickel cathode,LiNi0.8Co0.1Mn0.1O_(2)(NCM811),and sulfide-solid electrolyte are a promising combination for all-solid-state lithium batteries(ASSLBs).However,this combination faces the issue of interfacial instability between the cathode and electrolyte.Given the surface alkalinity of NCM811,we propose a strategy to construct a solid-polymer-electrolyte(SPE)interphase on NCM811 surface by leveraging the surface alkaline residues to nucleophilically initiate the in-situ ring-opening polymerization of cyclic organic molecules.As a proof-of-concept,this study demonstrates that the ring-opening copolymerization of 1,3-dioxolane and maleic anhydride produces a homogeneous,compact,and conformal SPE layer on NCM811 surface to prevent the cathode from contact and reaction with Li6PS5Cl solid-state electrolyte.Consequently,the SPE-modified-NCM811 in ASSLBs exhibits high capacities of 193.5 mA h g^(-1) at 0.2 C,160.9 mA h g^(-1) at 2.0 C and 112.3 mA h g^(-1) at 10 C,and particularly,excellent long-term cycling stabilities over 11000 cycles with a 71.95%capacity retention at 10 C at 25℃,as well as a remained capacity of 117.9 mA h g^(-1) after 8000 cycles at 30 C at 60℃,showing a great application prospect.This study provides a new route for creating electrochemically and structurally stable solid-solid interfaces for ASSLBs.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
A novel approach for the efficient synthesis of 2-phosphinoylindoles has been devised through P-centered anion nucleophilic addition to 2-isocyanobenzaldehydes,followed by cascade cyclization.This method uniquely empl...A novel approach for the efficient synthesis of 2-phosphinoylindoles has been devised through P-centered anion nucleophilic addition to 2-isocyanobenzaldehydes,followed by cascade cyclization.This method uniquely employs base-promoted activation without requiring metals,light,or electrical energy,thereby offering a metal-free strategy for constructing phosphine-functionalized indoles.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
A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electroph...A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,6-dinitrobenzofuroxan.The global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,6-dinitrobenzofuroxan.Evaluating the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are preserved.Comparing the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,6-dinitrobenzofuroxan.This approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are reacting.The local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,6-dinitrobenzofuroxan.The atoms selected by this procedure provide valuable information about the local reactivity of the indoles.We further show that this information about the most reactive atoms on each reactant,combined with the spatial distribution of the nucleophilic and electrophilic Fukui functions of both reactants,allows one to propose non-trivial candidates of starting geometries for the search of the transition state structures present in these reactions.展开更多
The nucleophilic displacement reaction of n-bromooctane and potassium iodide in ionic liquid based on cyclic guanidinium cation(2) was investigated. The kinetic reasult shows that the rate of the reaction is enhanced ...The nucleophilic displacement reaction of n-bromooctane and potassium iodide in ionic liquid based on cyclic guanidinium cation(2) was investigated. The kinetic reasult shows that the rate of the reaction is enhanced in ionic liquid (2). The same reaction in [bmim][PF6](1)(where bmim=1-butyl-3-methylimidazolium) was also studied. It was found that as a reaction medium ionic liquid (2) is better than (1) for nucelophilic displacement reactions.展开更多
The rate constants of the nucleophilic reactions between amines and benzhydrylium ions were calculated using first-principles theoretical methods. Solvation models including PCM, CPCM, and COSMORS, as well as differen...The rate constants of the nucleophilic reactions between amines and benzhydrylium ions were calculated using first-principles theoretical methods. Solvation models including PCM, CPCM, and COSMORS, as well as different types of atomic radii including UA0, UAKS, UAHF, Bondi, and UFF, and several single-point energy calculation methods （B3LYP, B3P86, B3PW91, BHANDH, PBEPBE, BMK, M06, MP2, and ONIOM method） were examined. By comparing the correlation between experimental rate constants and the calculated values, the ONIOM（CCSD（T）/6-311＋＋G（2df,2p）：B3LYP/6-311＋＋G（2df,2p））//B3LYP/6- 31G（d）/PCM/UFF） method was found to perform the best. This method was then employed to calculate the rate constants of the reactions between diverse amines and diarylcarbenium ions. The calculated rate constants for 65 reactions of amines with diarylcarbenium ions are in agreement with the experimental values, indicating that it is feasible to predict the rate constant of a reaction between an amine and a diarylcarbenium ion through ab initio calculation.展开更多
Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions....Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.展开更多
Biothiols,including cysteine(Cys),homocysteine(Hey),and glutathione(GSH) play important roles in physiological processes,and the detection of thiol using fluorescent probes has attracted attention due to their high se...Biothiols,including cysteine(Cys),homocysteine(Hey),and glutathione(GSH) play important roles in physiological processes,and the detection of thiol using fluorescent probes has attracted attention due to their high sensitivity and selectively and invasive on-time imaging.However,the similar structures and reactivity of these biothiols present great challenges for selective detection.This review focused on the the "aromatic nucleophilic substitution-rearrangement(SNAr-rearrangement) mechanism",which provided a powerful tool to design fluorescent probes for the discrimination between biothiols.We classify the fluorescent probes according to types of fluorophores,such as difluoroboron dipyrromethene(BODIPY),nitrobenzoxadiazole(NBD),cyanine,pyronin,naphthalimide,coumarin,and so on.We hope this review will inspire exploration of new fluorescent probes for biothiols and other relevant analytes.展开更多
MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still chal...MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still challenges in modifying the surface functional groups of MXene to further improve the electrochemical performance and increase the structure variety for MXene-based sulfur host.Herein,we report an efficient and flexible nucleophilic substitution(S_(N))strategy to modify the Ti_(3)C_(2)T_(x) surface terminations and purposefully designed Magnolol-modified Ti_(3)C_(2)T_(x)(M-Ti_(3)C_(2)T_(x))as powerful cathode host materials.Benefiting from more C-Ti-O bonds forming and diallyl groups terminations reducing after the dehalogenation and nucleophilic addition reactions,the given M-Ti_(3)C_(2)T_(x) electrode could effectively suppress the lithium polysulfides shuttling via chemisorption and C—S covalent bond formation.Besides,the Magnolol-modified Ti_(3)C_(2)T_(x) significantly accelerates polysulfide redox reaction and reduces the activation energy of Li_(2) S decomposition.As a result,the as-prepared M-Ti_(3)C_(2)T_(x) electrode displays an excellent rate capability and a high reversible capacity of 7.68 mAh cm^(-2)even under 7.2 mg cm^(-2)S-loaded with a low decay rate of 0.07%(from 2 nd cycle).This flexible surface-modified strategy for MXene terminations is expected to be extended to other diverse MXene applications.展开更多
基金National Science & Technology Major Project of China(Grant No.2009ZX09501-002)National Natural Science Foundation of China(Grant No.20802006).
文摘Based on the density functional theory,we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons.Descriptors including global softness,Fukui function,local softness and local mulliken charge were calculated at SVWN/DN~* level of DFT with PC Spartan Pro.Nucleophilicity and basicity of 28 selected compounds were classified based on intensity.BP algorithm of artificial neural network(ANN) was employed to study the relationship between the descriptors and nucleophilicity/basicity.Cross-validation was carried out to avoid the over-fitting in training of ANN.A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons.The results show that the prediction based on the network matches with the experimental results well.The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity.The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.
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Foundation items： National Science ＆ Technology Major Project of China （Grant No. 2009ZX09501-002）, National Natural Science Foundation of China （Grant No. 20802006）.
文摘Based on the density functional theory, we described here a method to investigate the quantitative relationship between nucleophilicity/basicity and HSAB-theory-based properties of compounds with lone-pair electrons. Descriptors including global softness, Fukui function, local softness and local mulliken charge were calculated at SVWN/DN＊ level of DFT with PC Spartan Pro. Nucleophilicity and basicity of 28 selected compounds were classified based on intensity. BP algorithm of artificial neural network （ANN） was employed to study the relationship between the descriptors and nucleophilicity/basicity. Cross-validation was carried out to avoid the over-fitting in training of ANN. A BP network was trained to quantify the relationship between HSAB-theory-based properties and nucleophilicity/basicity of compounds with lone-pair electrons. The results show that the prediction based on the network matches with the experimental results well. The local softness and Fukui function have a better relationship with nucleophilicity and local mulliken charge than with the basicity. The trained BP network could be utilized for predicting the nucleophilicity/basicity of compounds or functional groups with lone-pair electrons.
文摘High nucleophilicity of formate toward polyhalofluoroalkenes under acidic condition is described. This reaction offers a convenient method for the synthesis of E-α,β-unsaturated polyhalofluorocarboxylic acids.
基金the National Key R&D Program of China(No.2023YFC2308000)the National Natural Science Foundation of China(Nos.22478153,22477046,22177041)+2 种基金the Max Planck Society International Partner Group Programthe China Scholarship Council(CSC)the Fundamental Research Funds for the Central Universities for funding.
文摘Pseudomonas aeruginosa is an opportunistic pathogen responsible for severe nosocomial infections.This multidrug-resistant bacterium can cause pneumonia and cystic fibrosis,both of which are associated with high morbidity and mortality rates.The lipopolysaccharide of P.aeruginosa serves as an attractive target for the development of effective glycoconjugate vaccines.In this article,we report the first chemical synthesis of the highly challenging tetrasaccharide repeating unit of the P.aeruginosa serotype O3 O-antigen using a two-directional[1+(2+1)]glycosylation strategy.The synthesis is particularly challenging due to the poor nucleophilicity of the axial C4 hydroxyl group of l-galactose and the steric hindrance imposed by the 3S-hydroxybutyryl(Hb)chain.Furthermore,the presence of an acetyl group at the ortho position relative to the glycosylation site on l-galactose can lead to undesirable acetyl migration.Additionally,it is noteworthy that the selective removal of a 2-naphthylmethyl ether(Nap)during the late stages of synthesis,particularly in the presence of multiple benzyl groups,can be somewhat challenging to predict.Through the careful selection of synthetic strategies,building blocks,and optimized reaction conditions,we achieved the stereoselective glycosylations,selective oxidation of primary alcohols,remarkable enhancement of acceptor activity,and efficient introduction of the 3S-Hb group.The synthetic methodology presented in this work serves as a valuable reference for the preparation of structurally related oligosaccharides.By incorporating an aminopropyl linker,the target tetrasaccharide facilitates glycan microarray preparation and in vivo immunological assessments,thereby accelerating progress toward a synthetic glycoconjugate vaccine for P.aeruginosa.
基金supported by the National Key R&D Program of China(2021YFB3800300).
文摘High-nickel cathode,LiNi0.8Co0.1Mn0.1O_(2)(NCM811),and sulfide-solid electrolyte are a promising combination for all-solid-state lithium batteries(ASSLBs).However,this combination faces the issue of interfacial instability between the cathode and electrolyte.Given the surface alkalinity of NCM811,we propose a strategy to construct a solid-polymer-electrolyte(SPE)interphase on NCM811 surface by leveraging the surface alkaline residues to nucleophilically initiate the in-situ ring-opening polymerization of cyclic organic molecules.As a proof-of-concept,this study demonstrates that the ring-opening copolymerization of 1,3-dioxolane and maleic anhydride produces a homogeneous,compact,and conformal SPE layer on NCM811 surface to prevent the cathode from contact and reaction with Li6PS5Cl solid-state electrolyte.Consequently,the SPE-modified-NCM811 in ASSLBs exhibits high capacities of 193.5 mA h g^(-1) at 0.2 C,160.9 mA h g^(-1) at 2.0 C and 112.3 mA h g^(-1) at 10 C,and particularly,excellent long-term cycling stabilities over 11000 cycles with a 71.95%capacity retention at 10 C at 25℃,as well as a remained capacity of 117.9 mA h g^(-1) after 8000 cycles at 30 C at 60℃,showing a great application prospect.This study provides a new route for creating electrochemically and structurally stable solid-solid interfaces for ASSLBs.
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.
基金Project supported by the National Natural Science Foundation of China(Nos.22301160,21702121,21602123)the Programme of Introducing Talents of Discipline to Universities(111 Project,No.D20015)+3 种基金the Natural Science Foundation of Hubei Province(Nos.2025AFA116,2025AFD270,2023AFB026)the China Postdoctoral Science Foundation(No.2023M742043)the Hubei Three Gorges Laboratory Foundation(Nos.SC240014,SC232008,SC213008)the Foundation of Hubei Key Laboratory of Natural Products Research and Development(Nos.2024NPRD08,2022NPRD04)。
文摘A novel approach for the efficient synthesis of 2-phosphinoylindoles has been devised through P-centered anion nucleophilic addition to 2-isocyanobenzaldehydes,followed by cascade cyclization.This method uniquely employs base-promoted activation without requiring metals,light,or electrical energy,thereby offering a metal-free strategy for constructing phosphine-functionalized indoles.
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UOV was supported in part by Conacyt through a doctoral fellowship. JLG thanks Conacyt for grant 237045, and AV thanks Conacyt for grant Fronteras 867.
文摘A global and local charge transfer partitioning model,based on the cornerstone theory developed by Robert G.Parr and Robert G.Pearson,which introduces two charge transfer channels(one for accepting electrons(electrophilic) and another for donating(nucleophilic)),is applied to the reaction of a set of indoles with 4,6-dinitrobenzofuroxan.The global analysis indicates that the prevalent electron transfer mechanism in the reaction is a nucleophilic one on the indoles,i.e.,the indoles under consideration transfer electrons to 4,6-dinitrobenzofuroxan.Evaluating the reactivity descriptorswith exchange-correlation functionals including exact exchange(global hybrids) yields slightly better correlations than those obtained with generalized gradient-approximated functionals;however,the trends are preserved.Comparing the trend obtained with the number of electrons donated by the indoles,and predicted by the partitioning model,with that observed experimentally based on the measured rate constants,we propose that the number of electrons transferred through this channel can be used as a nucleophilicity scale to order the reactivity of indoles towards 4,6-dinitrobenzofuroxan.This approach to obtain reactivity scales has the advantage of depending on the intrinsic properties of the two reacting species;therefore,it opens the possibility that the same group of molecules may show different reactivity trends depending on the species with which they are reacting.The local model allows systematic incorporation of the reactive atoms based on the their decreasing condensed Fukui functions,and the correlations obtained by increasing the number of reactive atoms participating in the local analysis of the transferred nucleophilic charge improve,reaching an optimal correlation,which in the present case indicates keeping three atoms from the indoles and two from 4,6-dinitrobenzofuroxan.The atoms selected by this procedure provide valuable information about the local reactivity of the indoles.We further show that this information about the most reactive atoms on each reactant,combined with the spatial distribution of the nucleophilic and electrophilic Fukui functions of both reactants,allows one to propose non-trivial candidates of starting geometries for the search of the transition state structures present in these reactions.
文摘The nucleophilic displacement reaction of n-bromooctane and potassium iodide in ionic liquid based on cyclic guanidinium cation(2) was investigated. The kinetic reasult shows that the rate of the reaction is enhanced in ionic liquid (2). The same reaction in [bmim][PF6](1)(where bmim=1-butyl-3-methylimidazolium) was also studied. It was found that as a reaction medium ionic liquid (2) is better than (1) for nucelophilic displacement reactions.
文摘The rate constants of the nucleophilic reactions between amines and benzhydrylium ions were calculated using first-principles theoretical methods. Solvation models including PCM, CPCM, and COSMORS, as well as different types of atomic radii including UA0, UAKS, UAHF, Bondi, and UFF, and several single-point energy calculation methods （B3LYP, B3P86, B3PW91, BHANDH, PBEPBE, BMK, M06, MP2, and ONIOM method） were examined. By comparing the correlation between experimental rate constants and the calculated values, the ONIOM（CCSD（T）/6-311＋＋G（2df,2p）：B3LYP/6-311＋＋G（2df,2p））//B3LYP/6- 31G（d）/PCM/UFF） method was found to perform the best. This method was then employed to calculate the rate constants of the reactions between diverse amines and diarylcarbenium ions. The calculated rate constants for 65 reactions of amines with diarylcarbenium ions are in agreement with the experimental values, indicating that it is feasible to predict the rate constant of a reaction between an amine and a diarylcarbenium ion through ab initio calculation.
文摘Cross-linked poly（diallyldimethylammonium chloride） and its derivative copolymers were synthesized and used as phase transfer catalyst in the nucleophilic substitution reaction especially halogen exchange reactions.In addition,the effect of hydrophilic-hydrophobic character of the polymers in the nucleophilic reactions was investigated.
基金financially supported by the National Natural Science Foundation of China (No. 21525206)
文摘Biothiols,including cysteine(Cys),homocysteine(Hey),and glutathione(GSH) play important roles in physiological processes,and the detection of thiol using fluorescent probes has attracted attention due to their high sensitivity and selectively and invasive on-time imaging.However,the similar structures and reactivity of these biothiols present great challenges for selective detection.This review focused on the the "aromatic nucleophilic substitution-rearrangement(SNAr-rearrangement) mechanism",which provided a powerful tool to design fluorescent probes for the discrimination between biothiols.We classify the fluorescent probes according to types of fluorophores,such as difluoroboron dipyrromethene(BODIPY),nitrobenzoxadiazole(NBD),cyanine,pyronin,naphthalimide,coumarin,and so on.We hope this review will inspire exploration of new fluorescent probes for biothiols and other relevant analytes.
基金the support from CNPC Innovation Found(2021DQ02-1001)Liao Ning Revitalization Talents Program(XLYC1907144)Xinghai Talent Cultivation Plan(X20200303)。
文摘MXene-based materials have gained considerable attention for lithium-sulfur(Li-S)batteries cathode materials due to their superior electric conductivity and high affinitive to polysulfides.However,there are still challenges in modifying the surface functional groups of MXene to further improve the electrochemical performance and increase the structure variety for MXene-based sulfur host.Herein,we report an efficient and flexible nucleophilic substitution(S_(N))strategy to modify the Ti_(3)C_(2)T_(x) surface terminations and purposefully designed Magnolol-modified Ti_(3)C_(2)T_(x)(M-Ti_(3)C_(2)T_(x))as powerful cathode host materials.Benefiting from more C-Ti-O bonds forming and diallyl groups terminations reducing after the dehalogenation and nucleophilic addition reactions,the given M-Ti_(3)C_(2)T_(x) electrode could effectively suppress the lithium polysulfides shuttling via chemisorption and C—S covalent bond formation.Besides,the Magnolol-modified Ti_(3)C_(2)T_(x) significantly accelerates polysulfide redox reaction and reduces the activation energy of Li_(2) S decomposition.As a result,the as-prepared M-Ti_(3)C_(2)T_(x) electrode displays an excellent rate capability and a high reversible capacity of 7.68 mAh cm^(-2)even under 7.2 mg cm^(-2)S-loaded with a low decay rate of 0.07%(from 2 nd cycle).This flexible surface-modified strategy for MXene terminations is expected to be extended to other diverse MXene applications.
