Lewis base-catalyzed annulations of allenoates have been one of the most powerful synthetic strategies for the synthesis of various valuable cycles,especially in the preparation of biologically active natural products...Lewis base-catalyzed annulations of allenoates have been one of the most powerful synthetic strategies for the synthesis of various valuable cycles,especially in the preparation of biologically active natural products and pharmaceuticals.Generally,the effective Lewis bases mainly include tertiary phosphine,NHC and tertiary amine catalysts,among those catalysis,tertiary amine Lewis bases have proven to be effective catalysts for a range of synthetic transformations.In the past decades,tremendous progress in-volving tertiary amines-promoted cycloaddition of allenoates has been made in the chemoselective con-struction of valuable motifs.This review describes a comprehensive and updated summary of tertiary amine Lewis base-promoted annulation reactions of allenoates.Diverse reactivities,chemoselectivties and detailed reaction mechanisms will be highlighted in this review.展开更多
A Lewis base catalyzed ring expansion of isatin with 2,2,2-trifluorodiazoethane(CF3 CHN2)is developed.It is characterized that the merge of tetramethylethylenediamine and CF3 CHN2 generates reactive triazene intermedi...A Lewis base catalyzed ring expansion of isatin with 2,2,2-trifluorodiazoethane(CF3 CHN2)is developed.It is characterized that the merge of tetramethylethylenediamine and CF3 CHN2 generates reactive triazene intermediates,which construct substituted 3-hydroxy-4-(trifluoromethyl)quinolinones with high efficiency.Synthetic application of the procedure is broadened by 3-trifluormethylpyrazole fused3-hydroxy-4-(trifluoromethyl)quinolinone synthesis.展开更多
Metal/nucleophilic Lewis base dual catalysis has been recognized as a reliable and promising strategy for finishing ideal organic synthesis over the past decades.The new strategy can usually achieve some chemical reac...Metal/nucleophilic Lewis base dual catalysis has been recognized as a reliable and promising strategy for finishing ideal organic synthesis over the past decades.The new strategy can usually achieve some chemical reactions that cannot be realized by the traditionally mono-catalytic system,dramatically expanding the synthetic utility of chemical transformations by leveraging additional activation modes.Thus considerable progress has been made in the synthesis of a wide range of heterocyclic and biologically active compounds by using the combination of diversely metal/nucleophilic Lewis base dual catalysts,including metal/phosphine,metal/N-heterocyclic carbene(NHC)and metal/tertiary amine dual catalysis systems.In this review,we describe a comprehensive and updated advance of metal/nucleophilic Lewis base dual catalytic annualtion reactions,meanwhile,the related mechanism and the application of these annulation strategies in natural product total synthesis will be highlighted in detail.展开更多
Heteroatom-doped carbon has been demonstrated to be one of the most promising non-noble metal catalysts with high catalytic activity and stability through the modification of the electronic and geometric structures.In...Heteroatom-doped carbon has been demonstrated to be one of the most promising non-noble metal catalysts with high catalytic activity and stability through the modification of the electronic and geometric structures.In this study,we develop a novel solvent method to prepare interconnected N,S co-doped three-dimensional（3D）carbon networks with tunable nanopores derived from an asso-ciated complex based on melamine and sodium dodecylbenzene sulfonate（SDBS）.After the intro-duction of silica templates and calcination,the catalyst exhibits 3D networks with interconnected 50-nm pores and partial graphitization.With the increase of the number of Lewis base sites caused by the N doping and change of the carbon charge and spin densities caused by the S doping,the designed N,S co-doped catalyst exhibits a similar electrochemical activity to that of the commercial 20-wt%Pt/C as an oxygen reduction reaction catalyst.In addition,in an aluminum-air battery,the proposed catalyst even outperforms the commercial 5-wt%Pt/C catalyst.Both interconnected porous structures and synergistic effects of N and S contribute to the superior catalytic perfor-mance.This study paves the way for the synthesis of various other N-doped and co-doped carbon materials as efficient catalysts in electrochemical energy applications.展开更多
The Lewis base-supported terminal uranium imido metallocene,[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(dmap)(2),is readily accessible from the reaction of[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)UMe_(2)(...The Lewis base-supported terminal uranium imido metallocene,[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(dmap)(2),is readily accessible from the reaction of[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)UMe_(2)(1)with mesitylNH_(2)in toluene in the presence of 4-dimethylaminopyridine(dmap).With compound 2 in hand,its reactivity towards small molecules was studied in detail.It reacts with terminal alkynes such as PhCuCH to form the amido alkynyl complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[N(mesityl)CHvCHPh](CuCPh)(3)exclusively.In the reaction with thio-ketone Ph_(2)CS,CS_(2),isothiocyanate PhNCS and ketone Ph_(2)CO,the initial[2+2]cycloaddition intermediates are too labile to be isolated,yielding[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U(S_(2)CPh_(2))(dmap)(4)or dimeric sulfido and oxido complexes{[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U}_(2)(μ-E)_(2)(E=S(5),O(6)),respectively.Moreover,complex 2 may also behave as a nucleophile in the reaction with bis(catecholato)diboron(B_(2)cat_(2)),yielding the amido catecholate complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[N(mesityl)B(BO_(2)C_(6)H_(4))O(C_(6)H_(4))O](8).In addition,the imido moiety of 2 may also engage in deprotonation reactions as demonstrated by its reactivity with the carboxamide PhCONH(p-tolyl)and organic nitrile PhCH_(2)CN,obtaining the uranium(IV)bis-amidate complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[OC(Ph)N(p-tolyl)]_(2)(7)and the uranium(IV)iminato amido complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[N(mesityl)vC(CH_(2)Ph)NH](NvCvCHPh)(9),respectively.Furthermore,2 may also participate in single-and two-electron transfer processes.It is singly oxidized by CuI,Ph_(2)S_(2),Ph_(2)Se_(2)and Ph_(3)CN_(3),yielding the uranium(V)imido complexes[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(X)(X=I(12),PhS(13),PhSe(14),and N_(3)(17)),or doubly oxidized by organic azides(RN_(3)),forming the uranium(VI)bis-imido metallocenes[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(vNR)(R=p-tolyl(15),mesityl(16)),respectively.Nevertheless,the addition of 1,2-diphenylhydrazine PhNHNHPh to complex 2 results in deprotonation and ligand elimination processes,yielding the uranium(V)bis-imido complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]U[vNPh]_(2)(dmap)_(3)(11)in the presence of dmap.展开更多
Polyhedral boranes are a class of well-known boron molecular clusters widely used in energy;chemistry;medicine;and materials science because of their unique physical and chemical properties.Great efforts have been mad...Polyhedral boranes are a class of well-known boron molecular clusters widely used in energy;chemistry;medicine;and materials science because of their unique physical and chemical properties.Great efforts have been made in the past decades to find more effective synthetic methods for this important class of boron compounds.However;existing synthetic methods suffer from low efficiency and low selectivity.Herein;we report a facile one-pot synthesis of[(CH_(3))3S]_(2)B_(12)H_(12) with moderate yields at mild conditions.The mechanisms for the multi-step chemoselective synthesis of B_(12)H_(12)^(2-)without other by-products are elucidated based on theoretical results and our previous work.The Lewis base used in B–H bond condensation reaction;which acts as a hydrogen or to balance the newly generated polyhedral borane charges;is proposed and studied in detail.The current study has led to a more effective and selective synthetic method for B_(12)H_(12)^(2-) and has also implicated the syntheses of other new polyhedral boranes.展开更多
Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast d...Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast during the solution-deposited process,resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer.Here,we employed theπ-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks,leading to a compact and uniform perovskite film with large increase in the carrier lifetime.Meanwhile,the introduction of theπ-conjugated systems also retards the permeation of moisture into perovskite crystal,which significantly suppresses the film degradation in air.These benefits contributed to a stabilizing power conversion efficiency(PCE)of 10.1%for the TPSCs and maintained over 90%of its initial PCE after 1000-h light soaking in air.Also,a steady-state efficiency of 9.2%was certified at the accredited test center.展开更多
Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time.Various selenium-containing tetrasubstituted alkenes were readi...Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time.Various selenium-containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities.As the substrates were 1-ethynyl naphthol derivatives,linear selenium-containing tetrasubstituted alkenes were produced via intermolecular oxygen nucleophilic attack in the absence of acid additive;in contrast,cyclic selenium-containing tetrasubstituted alkenes were generated through intramolecular carbon nucleophilic capture with the addition of Brønsted acid.展开更多
In the recent decade, the development and application of organocatalysis for CO_2 transformation into useful chemicals have attracted much attention. Among these organocatalysts, Lewis base-CO_2 adducts(LB-CO_2) were ...In the recent decade, the development and application of organocatalysis for CO_2 transformation into useful chemicals have attracted much attention. Among these organocatalysts, Lewis base-CO_2 adducts(LB-CO_2) were found to be more efficient.The used Lewis base has great effect on the catalytic activity of its CO_2 adduct. This review reports the recent progress in LB-CO_2 adducts catalyzed the cyclization of CO_2 with epoxides or aziridines to afford cyclic carbonates or oxazolidinones,the carboxylation of CO_2 with propargylic alcohols to α-alkylidene cyclic carbonates, and the reduction of CO_2 to methanol,formamides and methylamines, with the focus on the catalytic mechanism.展开更多
It was found that, when the Baylis-Hillman reaction of arylaldehydes withmethyl vinyl ketone was carried out at below - 20℃ in the presence of boron (Ⅲ) tribromide ortitanium (Ⅳ) bromide using a catalytic amount of...It was found that, when the Baylis-Hillman reaction of arylaldehydes withmethyl vinyl ketone was carried out at below - 20℃ in the presence of boron (Ⅲ) tribromide ortitanium (Ⅳ) bromide using a catalytic amount of Lewis base such as amine, the brominated compoundsand the Baylis-Hillman adducts could be obtained as the major products in good yields for variousaryl aldehydes. But at room temperature, the elimination products were the major products. Inaddition, the palladium catalyzed allylic substitution reactions of the e-limination products werealso examined.展开更多
The first asymmetric decarboxylative[3+2]-cycloaddition of ethynyl indoloxazolidones with carboxylic acids has been developed under synergistic catalysis of copper and chiral Lewis base.This protocol provides a direct...The first asymmetric decarboxylative[3+2]-cycloaddition of ethynyl indoloxazolidones with carboxylic acids has been developed under synergistic catalysis of copper and chiral Lewis base.This protocol provides a direct and modular approach to biologically important pyrrolo[1,2-a]indoles bearing two vicinal stereogenic centers with excellent diastereo-and enantioselectivities(up to>20:1 dr and>99%ee).In addition,the utility of this methodology was demonstrated by scaled-up reaction and several synthetic transformations of the cycloadduct.展开更多
Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxi...Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of carbon.Herein, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).展开更多
Lewis acid(LA)and Lewis base(LB)sites on catalyst surfaces play a pivotal role in catalytic reactions.By precisely modulating the type,density,and spatial distribution of these Lewis acid/base sites,catalytic performa...Lewis acid(LA)and Lewis base(LB)sites on catalyst surfaces play a pivotal role in catalytic reactions.By precisely modulating the type,density,and spatial distribution of these Lewis acid/base sites,catalytic performance indicators such as catalytic activity,selectivity,and stability can be effectively optimized.As a result,they become essential parameters that must be considered in the design and development of high-efficiency catalysts.This study proposes a surface engineering method to accurately control the concentration of surface LA and LB sites in defect-laden In_(2)O_(3-x)(OH)_(y)(denoted as N-n%-IO),establishing three types of LB/LA stoichiometric ratios with different photocatalytic CO_(2)hydrogenation performances.It is demonstrated that the LB-rich system(LB/LA>1)shows suppressed activity.In contrast,the balanced stoichiometric ratio system(LB/LA=1)attains an optimal methanol yield(179.79μmol g^(-1)h^(-1))and selectivity(43.67%),while the LA-rich system(LB/LA<1)exhibits the best CO production rate(1913.76μmol g^(-1)h^(-1))and selectivity(94.96%).Systematic experiments disclose that the balanced LB/LA system with adjacent surface frustrated Lewis pairs(SFLPs)can effectively facilitate the adsorption/activation of reactants,stabilize intermediates,and regulate the dynamic behavior of photo-generated carriers.However,the imbalanced LB/LA systems either lack necessary active sites or can only follow an oxygen vacancy-mediated pathway during photocatalytic CO_(2)hydrogenation.This work offers a comprehensive understanding of the crucial functions of surface Lewis acid/base sites in the product distribution of solar-driven CO_(2)reduction.展开更多
To systematically study the effect of Lewis acid sites(LASs)and Lewis base sites(LBSs)in MOF materials for the CO_(2)cycloaddition reaction,four isomorphous copper polyhedron-based MOFs(Cu-PMOFs),JLU-Liu20,JLU-Liu21,J...To systematically study the effect of Lewis acid sites(LASs)and Lewis base sites(LBSs)in MOF materials for the CO_(2)cycloaddition reaction,four isomorphous copper polyhedron-based MOFs(Cu-PMOFs),JLU-Liu20,JLU-Liu21,JLU-Liu22 and JLU-Liu46 with different amounts of LASs and LBSs were selected to investigate their CO_(2)fixation catalytic performance.It is commendable that the catalytic capabilities of the four Cu-PMOFs exceed that of most reported MOF-based catalysts.展开更多
A synthetic route to flapping poly-Lewis acids(PLAs)based on dibenzocyclooctatetraene was developed.The reactivity of tetradentate boron and aluminium containing PLAs towards various Lewis bases(LB)including drugs was...A synthetic route to flapping poly-Lewis acids(PLAs)based on dibenzocyclooctatetraene was developed.The reactivity of tetradentate boron and aluminium containing PLAs towards various Lewis bases(LB)including drugs was investigated in detail.By using different monodentate LBs,the different effective Lewis acidities(eLA)of the respective pairings were determined and compared with each other.The reaction with multidentate LBs yielded a range of adducts,which were analysed in solution by NMR methods,including DOSY NMR spectroscopy,and in the solid state by X-ray diffraction.The adducts include specific oligomers,and coordination polymers constructed via B-P,Al-P and Al-N interactions.The solid-state structures of these coordination polymers have been determined.The results of complexation of bidentate LB by the tetradentate PLA show that LB is preferentially chelated in the binding pockets,which does not impede the flapping movement during chelating complexation.This phenomenon can be attributed to a reduction in entropy when this flapping motion is lost.The aluminium containing PLAs were observed to form a complex with two caffeine molecules,exhibiting remarkable preference for oxygen functions.In contrast,the reaction with theobromine resulted in the degradation of the PLAs due to the presence of acidic protons in theobromine,leading to the formation of a dimeric aluminium containing theobromine derivative.These findings demonstrate the interaction of PLAs with drugs.They provide a foundation for the advancement of PLAs with a tuneable orientation of Lewis acidic functions.展开更多
Rechargeable magnesium batteries(RMBs)are considered the promising candidates for post lithium-ion batteries due to the abundant storage,high capacity,and dendrite-rare characteristic of Mg anode.However,the lack of p...Rechargeable magnesium batteries(RMBs)are considered the promising candidates for post lithium-ion batteries due to the abundant storage,high capacity,and dendrite-rare characteristic of Mg anode.However,the lack of practical electrolytes impedes the development and application of RMBs.Here,through a one-step reaction of LiCl congenital-containing Knochel–Hauser base TMPL(2,2,6,6-tetrame thylpiperidinylmagnesium chloride lithium chloride complex)with Lewis acid AlCl_(3),we successfully synthesized an efficient amino-magnesium halide TMPLA electrolyte.Raman and mass spectroscopy identified that the electrolyte comprises the typical di-nuclear copolymer[Mg_(2)Cl_(3)·6THF]+cation group and[(TMP)2AlCl_(2)]-anion group,further supported by the results of density functional theory calculations(DFT)and the Molecular dynamics(MD)simulations.The TMPLA electrolyte exhibits promising electrochemical performance,including available anodic stability(>2.65 V vs.SS),high ionic conductivity(6.05mS cm^(-1)),and low overpotential(<0.1 V)as well as appropriate Coulombic efficiency(97.3%)for Mg plating/stripping.Both the insertion Mo6S8cathode and conversion Cu S cathode delivered a desirable electrochemical performance with high capacity and good cycling stability based on the TMPLA electrolyte.In particular,when compatible with low cost and easily synthesized Cu S,the Cu S||Mg cell displayed an extremely high discharge capacity of 458.8 mAh g^(-1)for the first cycle and stabilized at 170.2 mAh g^(-1)with high Coulombic efficiency(99.1%)after 50 cycles at 0.05 C.Our work proposes an efficient electrolyte with impressive compatibility with Mg anode and insertion/conversion cathode for practical RMBs and provides a more profound knowledge of the Lewis acid–base reaction mechanisms.展开更多
A new Ce^(3+)modified Dawson-like polyoxometalate cluster(C_(2)H_(8)N)_(12)Na_(2)[H_(10){Ce(H_(2)O)_(5)}_(2)(Te_(2)W_(37)O_(132))]·^(39)H_(2)O was synthesized using pH and temperature-controlled one-pot strategy....A new Ce^(3+)modified Dawson-like polyoxometalate cluster(C_(2)H_(8)N)_(12)Na_(2)[H_(10){Ce(H_(2)O)_(5)}_(2)(Te_(2)W_(37)O_(132))]·^(39)H_(2)O was synthesized using pH and temperature-controlled one-pot strategy.The compound was characterized by single-crystal X-ray structure analysis,IR spectroscopy,thermogravimetric(TG)analysis,X-ray photoelectron spectroscopy(XPS),and electrospray ionization mass spectrometry(ESI-MS).Singlecrystal X-ray structure analysis revealed that there was a new{Te_(2)W_(37)O_(132)}structure and two Ce^(3+)in this compound.Moreover,it is notable that this compound presents excellent Lewis acid-and Lewis base activities in the condensation cyclization of 1,3-diketones with hydrazines/hydrazides or diamines.All the desired products were obtained in moderate to good yields(up to 99%)and with a high turnover number(up to 4347).展开更多
The stacking of multiple defect-rich grain boundaries(GBs)along the long transportation path(~3μm)of charge carriers in printable mesoscopic perovskite solar cells(p-MPSCs)impedes their power conversion efficiency(PC...The stacking of multiple defect-rich grain boundaries(GBs)along the long transportation path(~3μm)of charge carriers in printable mesoscopic perovskite solar cells(p-MPSCs)impedes their power conversion efficiency(PCE).Organic Lewis bases are widely utilized for defect passivation at GBs,but how their passivation efficiency affects energy loss remains unclear.Here we employed triphenylphosphine(TPP)and triphenylphosphine oxide(TPPO)as the model passivators in p-MPSCs.TPPO has a more negatively charged center than TPP,which enables its stronger coordination with one of the most common and detrimental defects at the GBs—undercoordinated lead.When added into the perovskite with the same ratio,TPPO passivates defects more significantly and thus less TPPO remaining inactive compared with TPP.Inactive organic passivators accumulated at the GBs could impose barriers to charge carrier transportation.Indeed,TPPO improves the device performance more significantly with a champion PCE of 20.54%achieved.Besides,the TPPO devices demonstrate excellent stability with 95%of initial PCE remaining after 600 h of maximum power point tracking at(55±5)℃.展开更多
Despite its great potential in supramolecular chemistry to achieve structural complexity and sophisticated functionality,the kinetic control over molecular self-assembly in coordination with supramolecular polymerizat...Despite its great potential in supramolecular chemistry to achieve structural complexity and sophisticated functionality,the kinetic control over molecular self-assembly in coordination with supramolecular polymerization still constitutes a challenge.Herein,the kinetically controlled supramolecular polymerization of porphyrin derivatives was achieved in aqueous media by a seeding method based on a metastable state generated by synergistic metalation and Lewis acid–base complexation.展开更多
The scope of stereochemistry recognition usually occurs near the chiral scaffold of a ligand or catalyst.Remote stereocontrol,which can surpass the limits of stereorecognition of remote prochiral centers,has long been...The scope of stereochemistry recognition usually occurs near the chiral scaffold of a ligand or catalyst.Remote stereocontrol,which can surpass the limits of stereorecognition of remote prochiral centers,has long been a challenging object of great interest in asymmetric catalysis.The current work realized the remote stereocontrol of 1,7-zwitterion intermediates formed from Huang's o-amino aryl MBH carbonates.With simple and easily accessibleβ-ICD as the bifunctional catalyst,multifunctionalized tetrahydroquinoline derivatives could be synthesized via(4+2)cycloadditions with excellent enantioselectivity and diastereoselectivity under mild conditions.The strategy possesses broad substrate scope,and three types of electron-deficient enones are successfully applied.Mechanistic studies disclosed the Lewis base-catalyzed reaction pathway,and H-bonding between the catalyst and enones is crucial for long-range stereocontrol.Scale-up reaction and transformations of the tetrahydroquinoline products demonstrated the potential of this strategy.展开更多
基金the National Natural Science Foundation of China(No.21702189)Key Scientific and Technological Project of Henan Province(No.202102310004)Zhengzhou University(No.JC21253007)of China for financial support.
文摘Lewis base-catalyzed annulations of allenoates have been one of the most powerful synthetic strategies for the synthesis of various valuable cycles,especially in the preparation of biologically active natural products and pharmaceuticals.Generally,the effective Lewis bases mainly include tertiary phosphine,NHC and tertiary amine catalysts,among those catalysis,tertiary amine Lewis bases have proven to be effective catalysts for a range of synthetic transformations.In the past decades,tremendous progress in-volving tertiary amines-promoted cycloaddition of allenoates has been made in the chemoselective con-struction of valuable motifs.This review describes a comprehensive and updated summary of tertiary amine Lewis base-promoted annulation reactions of allenoates.Diverse reactivities,chemoselectivties and detailed reaction mechanisms will be highlighted in this review.
基金financial support from the National Natural Science Foundation of China(No.81602977)the CAMS Innovation Fund for Medical Sciences(Nos.2019-RC-HL-010,2017-I2M-1013)+1 种基金the Science and Technology Development Project of Jilin Province of China(No.20190304050YY)China Association of Chinese Medicine(No.2017QNRC001)。
文摘A Lewis base catalyzed ring expansion of isatin with 2,2,2-trifluorodiazoethane(CF3 CHN2)is developed.It is characterized that the merge of tetramethylethylenediamine and CF3 CHN2 generates reactive triazene intermediates,which construct substituted 3-hydroxy-4-(trifluoromethyl)quinolinones with high efficiency.Synthetic application of the procedure is broadened by 3-trifluormethylpyrazole fused3-hydroxy-4-(trifluoromethyl)quinolinone synthesis.
基金the National Natural Science Foundation of China(No.21702189)the Key Scientific and Technological Project of Henan Province(No.202102310004)+1 种基金Science and Technology Research and Development Plan Joint Fund(cultivation of superior disciplines)Project(No.222301420042)Zhengzhou University(No.JC21253007)of China for financial support of this research.
文摘Metal/nucleophilic Lewis base dual catalysis has been recognized as a reliable and promising strategy for finishing ideal organic synthesis over the past decades.The new strategy can usually achieve some chemical reactions that cannot be realized by the traditionally mono-catalytic system,dramatically expanding the synthetic utility of chemical transformations by leveraging additional activation modes.Thus considerable progress has been made in the synthesis of a wide range of heterocyclic and biologically active compounds by using the combination of diversely metal/nucleophilic Lewis base dual catalysts,including metal/phosphine,metal/N-heterocyclic carbene(NHC)and metal/tertiary amine dual catalysis systems.In this review,we describe a comprehensive and updated advance of metal/nucleophilic Lewis base dual catalytic annualtion reactions,meanwhile,the related mechanism and the application of these annulation strategies in natural product total synthesis will be highlighted in detail.
基金supported by the National Natural Science Foundation of China (51674297)the Natural Science Foundation of Hunan Province (2016JJ2137)the Fundamental Research Funds for the Central Universities of Central South University (2015cx001)~~
文摘Heteroatom-doped carbon has been demonstrated to be one of the most promising non-noble metal catalysts with high catalytic activity and stability through the modification of the electronic and geometric structures.In this study,we develop a novel solvent method to prepare interconnected N,S co-doped three-dimensional（3D）carbon networks with tunable nanopores derived from an asso-ciated complex based on melamine and sodium dodecylbenzene sulfonate（SDBS）.After the intro-duction of silica templates and calcination,the catalyst exhibits 3D networks with interconnected 50-nm pores and partial graphitization.With the increase of the number of Lewis base sites caused by the N doping and change of the carbon charge and spin densities caused by the S doping,the designed N,S co-doped catalyst exhibits a similar electrochemical activity to that of the commercial 20-wt%Pt/C as an oxygen reduction reaction catalyst.In addition,in an aluminum-air battery,the proposed catalyst even outperforms the commercial 5-wt%Pt/C catalyst.Both interconnected porous structures and synergistic effects of N and S contribute to the superior catalytic perfor-mance.This study paves the way for the synthesis of various other N-doped and co-doped carbon materials as efficient catalysts in electrochemical energy applications.
基金National Natural Science Foundation of China(grant no.22271017)Deutsche Forschungsgemeinschaft(DFG)through the Heisenberg program(WA 2513/8)。
文摘The Lewis base-supported terminal uranium imido metallocene,[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(dmap)(2),is readily accessible from the reaction of[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)UMe_(2)(1)with mesitylNH_(2)in toluene in the presence of 4-dimethylaminopyridine(dmap).With compound 2 in hand,its reactivity towards small molecules was studied in detail.It reacts with terminal alkynes such as PhCuCH to form the amido alkynyl complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[N(mesityl)CHvCHPh](CuCPh)(3)exclusively.In the reaction with thio-ketone Ph_(2)CS,CS_(2),isothiocyanate PhNCS and ketone Ph_(2)CO,the initial[2+2]cycloaddition intermediates are too labile to be isolated,yielding[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U(S_(2)CPh_(2))(dmap)(4)or dimeric sulfido and oxido complexes{[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U}_(2)(μ-E)_(2)(E=S(5),O(6)),respectively.Moreover,complex 2 may also behave as a nucleophile in the reaction with bis(catecholato)diboron(B_(2)cat_(2)),yielding the amido catecholate complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[N(mesityl)B(BO_(2)C_(6)H_(4))O(C_(6)H_(4))O](8).In addition,the imido moiety of 2 may also engage in deprotonation reactions as demonstrated by its reactivity with the carboxamide PhCONH(p-tolyl)and organic nitrile PhCH_(2)CN,obtaining the uranium(IV)bis-amidate complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[OC(Ph)N(p-tolyl)]_(2)(7)and the uranium(IV)iminato amido complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U[N(mesityl)vC(CH_(2)Ph)NH](NvCvCHPh)(9),respectively.Furthermore,2 may also participate in single-and two-electron transfer processes.It is singly oxidized by CuI,Ph_(2)S_(2),Ph_(2)Se_(2)and Ph_(3)CN_(3),yielding the uranium(V)imido complexes[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(X)(X=I(12),PhS(13),PhSe(14),and N_(3)(17)),or doubly oxidized by organic azides(RN_(3)),forming the uranium(VI)bis-imido metallocenes[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]_(2)U^(V)N(mesityl)(vNR)(R=p-tolyl(15),mesityl(16)),respectively.Nevertheless,the addition of 1,2-diphenylhydrazine PhNHNHPh to complex 2 results in deprotonation and ligand elimination processes,yielding the uranium(V)bis-imido complex[η^(5)-1,3-(Me_(3)Si)_(2)C_(5)H_(3)]U[vNPh]_(2)(dmap)_(3)(11)in the presence of dmap.
基金supported by the National Natural Science Foundation of China(22171246,U1804253 to X.Chen,and 21773214 to D.Wei)L.S.Wang wishes to thank the US National Science Foundation for support under grant CHE-2403841.
文摘Polyhedral boranes are a class of well-known boron molecular clusters widely used in energy;chemistry;medicine;and materials science because of their unique physical and chemical properties.Great efforts have been made in the past decades to find more effective synthetic methods for this important class of boron compounds.However;existing synthetic methods suffer from low efficiency and low selectivity.Herein;we report a facile one-pot synthesis of[(CH_(3))3S]_(2)B_(12)H_(12) with moderate yields at mild conditions.The mechanisms for the multi-step chemoselective synthesis of B_(12)H_(12)^(2-)without other by-products are elucidated based on theoretical results and our previous work.The Lewis base used in B–H bond condensation reaction;which acts as a hydrogen or to balance the newly generated polyhedral borane charges;is proposed and studied in detail.The current study has led to a more effective and selective synthetic method for B_(12)H_(12)^(2-) and has also implicated the syntheses of other new polyhedral boranes.
基金supported by the National Natural Science Foundation of China(11574199,11674219,11834011)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning+1 种基金National Institute for Materials Science was supported by the New Energy and Industrial Technology Development Organization(NEDO,Japan)the KAKEHI Grant of Japan(18H02078)
文摘Tin-based perovskite solar cells(TPSCs)as the most promising candidate for lead-free PSCs have incurred extensive researches all over the world.However,the crystallization process of tin-based perovskite is too fast during the solution-deposited process,resulting in abundant pinholes and poor homogeneity that cause serious charge recombination in perovskite layer.Here,we employed theπ-conjugated Lewis base molecules with high electron density to systematically control the crystallization rate of FASnI3 perovskite by forming stable intermediate phase with the Sn-I frameworks,leading to a compact and uniform perovskite film with large increase in the carrier lifetime.Meanwhile,the introduction of theπ-conjugated systems also retards the permeation of moisture into perovskite crystal,which significantly suppresses the film degradation in air.These benefits contributed to a stabilizing power conversion efficiency(PCE)of 10.1%for the TPSCs and maintained over 90%of its initial PCE after 1000-h light soaking in air.Also,a steady-state efficiency of 9.2%was certified at the accredited test center.
基金the National Natural Science Foundation of China(Nos.22071149,21871178)the Natural Science Foundation of Shanghai(23ZR1428200)the Program for Professor of Special Appointment(Eastern Scholar)at Shanghai Institutions of Higher Learning for financial support.
文摘Lewis base catalyzed and Brønsted acid controlled chemodivergent electrophilic selenofunctionalizations of alkynes were developed for the first time.Various selenium-containing tetrasubstituted alkenes were readily obtained in moderate to excellent yields with complete E/Z selectivities.As the substrates were 1-ethynyl naphthol derivatives,linear selenium-containing tetrasubstituted alkenes were produced via intermolecular oxygen nucleophilic attack in the absence of acid additive;in contrast,cyclic selenium-containing tetrasubstituted alkenes were generated through intramolecular carbon nucleophilic capture with the addition of Brønsted acid.
基金supported by the National Natural Science Foundation of China(21402021)the Program for Changjiang Scholars and Innovative Research Team in University(IRT13008)
文摘In the recent decade, the development and application of organocatalysis for CO_2 transformation into useful chemicals have attracted much attention. Among these organocatalysts, Lewis base-CO_2 adducts(LB-CO_2) were found to be more efficient.The used Lewis base has great effect on the catalytic activity of its CO_2 adduct. This review reports the recent progress in LB-CO_2 adducts catalyzed the cyclization of CO_2 with epoxides or aziridines to afford cyclic carbonates or oxazolidinones,the carboxylation of CO_2 with propargylic alcohols to α-alkylidene cyclic carbonates, and the reduction of CO_2 to methanol,formamides and methylamines, with the focus on the catalytic mechanism.
文摘It was found that, when the Baylis-Hillman reaction of arylaldehydes withmethyl vinyl ketone was carried out at below - 20℃ in the presence of boron (Ⅲ) tribromide ortitanium (Ⅳ) bromide using a catalytic amount of Lewis base such as amine, the brominated compoundsand the Baylis-Hillman adducts could be obtained as the major products in good yields for variousaryl aldehydes. But at room temperature, the elimination products were the major products. Inaddition, the palladium catalyzed allylic substitution reactions of the e-limination products werealso examined.
基金This work is supported by the National Natural Science Foundation of China(Nos.21901072 and 21772038).
文摘The first asymmetric decarboxylative[3+2]-cycloaddition of ethynyl indoloxazolidones with carboxylic acids has been developed under synergistic catalysis of copper and chiral Lewis base.This protocol provides a direct and modular approach to biologically important pyrrolo[1,2-a]indoles bearing two vicinal stereogenic centers with excellent diastereo-and enantioselectivities(up to>20:1 dr and>99%ee).In addition,the utility of this methodology was demonstrated by scaled-up reaction and several synthetic transformations of the cycloadduct.
基金financial support of the National Natural Science Foundation of China (Grant No. 21263016, 21363015, 51662029, 21863006)the Youth Science Foundation of Jiangxi Province (Grant No. 20192BAB216001)the Key Laboratory of Jiangxi Province for Environment and Energy Catalysis (20181BCD40004)。
文摘Carbon materials have shown remarkable usefulness in facilitating the performance of insulating sulfur cathode for lithium–sulfur batteries owing to their excellent conductivity and porous structure. However,the anxiety is the poor affinity toward polar polysulfides due to the intrinsic nonpolar surface of carbon.Herein, we report a direct pyrolysis of the mixture urea and boric acid to synthesize B/N–codoped hierarchically porous carbon nanosheets(B–N–CSs) as efficient sulfur host for lithium–sulfur battery. The graphene–like B–N–CSs provides high specific surface area and porous structure with abundant micropores(1.1 nm) and low–range mesopores(2.3 nm), thereby constraining the sulfur active materials within the pores. More importantly, the codoped B/N elements can further enhance the polysulfide confinement through strong Li–N and B–S interaction based on the Lewis acid–base theory. These structural superiorities significantly suppress the shuttle effect by both physical confinement and chemical interaction, and promote the redox kinetics of polysulfide conversion. When evaluated as the cathode host, the S/B–N–CSs composite displays the excellent performance with a high reversible capacity up to 772 m A h g–1 at 0.5 C and a low fading rate of ^0.09% per cycle averaged upon 500 cycles. In particular, remarkable stability with a high capacity retention of 87.1% can be realized when augmenting the sulfur loading in the cathode up to 4.6 mg cm^(-2).
基金supported by the National Natural Science Foundation of China(22172086,22105117)the Taishan Scholars Program of Shandong Province(202103064)the Major Basic Research Project of Shandong Province(ZR2021ZD06)。
文摘Lewis acid(LA)and Lewis base(LB)sites on catalyst surfaces play a pivotal role in catalytic reactions.By precisely modulating the type,density,and spatial distribution of these Lewis acid/base sites,catalytic performance indicators such as catalytic activity,selectivity,and stability can be effectively optimized.As a result,they become essential parameters that must be considered in the design and development of high-efficiency catalysts.This study proposes a surface engineering method to accurately control the concentration of surface LA and LB sites in defect-laden In_(2)O_(3-x)(OH)_(y)(denoted as N-n%-IO),establishing three types of LB/LA stoichiometric ratios with different photocatalytic CO_(2)hydrogenation performances.It is demonstrated that the LB-rich system(LB/LA>1)shows suppressed activity.In contrast,the balanced stoichiometric ratio system(LB/LA=1)attains an optimal methanol yield(179.79μmol g^(-1)h^(-1))and selectivity(43.67%),while the LA-rich system(LB/LA<1)exhibits the best CO production rate(1913.76μmol g^(-1)h^(-1))and selectivity(94.96%).Systematic experiments disclose that the balanced LB/LA system with adjacent surface frustrated Lewis pairs(SFLPs)can effectively facilitate the adsorption/activation of reactants,stabilize intermediates,and regulate the dynamic behavior of photo-generated carriers.However,the imbalanced LB/LA systems either lack necessary active sites or can only follow an oxygen vacancy-mediated pathway during photocatalytic CO_(2)hydrogenation.This work offers a comprehensive understanding of the crucial functions of surface Lewis acid/base sites in the product distribution of solar-driven CO_(2)reduction.
基金supported by the National Natural Science Foundation of China(No.21771078 and 21621001)the 111 Project(B17020)the National Key Research and Development Program of China(2016YFB0701100).
文摘To systematically study the effect of Lewis acid sites(LASs)and Lewis base sites(LBSs)in MOF materials for the CO_(2)cycloaddition reaction,four isomorphous copper polyhedron-based MOFs(Cu-PMOFs),JLU-Liu20,JLU-Liu21,JLU-Liu22 and JLU-Liu46 with different amounts of LASs and LBSs were selected to investigate their CO_(2)fixation catalytic performance.It is commendable that the catalytic capabilities of the four Cu-PMOFs exceed that of most reported MOF-based catalysts.
基金funded by the Deutsche Forschungsgemeinschaft(DFG,German Research Foundation)grant MI 477/39-1,project no.424957011the Regional Computing Centre of the University of Cologne(RRZK)for providing computing time and support on the DFG-funded(Funding number:INST 216/512/1FUGG)HPC system CHEOPS.
文摘A synthetic route to flapping poly-Lewis acids(PLAs)based on dibenzocyclooctatetraene was developed.The reactivity of tetradentate boron and aluminium containing PLAs towards various Lewis bases(LB)including drugs was investigated in detail.By using different monodentate LBs,the different effective Lewis acidities(eLA)of the respective pairings were determined and compared with each other.The reaction with multidentate LBs yielded a range of adducts,which were analysed in solution by NMR methods,including DOSY NMR spectroscopy,and in the solid state by X-ray diffraction.The adducts include specific oligomers,and coordination polymers constructed via B-P,Al-P and Al-N interactions.The solid-state structures of these coordination polymers have been determined.The results of complexation of bidentate LB by the tetradentate PLA show that LB is preferentially chelated in the binding pockets,which does not impede the flapping movement during chelating complexation.This phenomenon can be attributed to a reduction in entropy when this flapping motion is lost.The aluminium containing PLAs were observed to form a complex with two caffeine molecules,exhibiting remarkable preference for oxygen functions.In contrast,the reaction with theobromine resulted in the degradation of the PLAs due to the presence of acidic protons in theobromine,leading to the formation of a dimeric aluminium containing theobromine derivative.These findings demonstrate the interaction of PLAs with drugs.They provide a foundation for the advancement of PLAs with a tuneable orientation of Lewis acidic functions.
基金financial support from the National Natural Science Foundation of China(Nos.21975159,2157316)the Shanghai Aerospace Science and Technology Innovation Fund(No.SAST2018-117)the Oceanic Interdisciplinary Program of Shanghai Jiao Tong University(No.WH410260401/006)。
文摘Rechargeable magnesium batteries(RMBs)are considered the promising candidates for post lithium-ion batteries due to the abundant storage,high capacity,and dendrite-rare characteristic of Mg anode.However,the lack of practical electrolytes impedes the development and application of RMBs.Here,through a one-step reaction of LiCl congenital-containing Knochel–Hauser base TMPL(2,2,6,6-tetrame thylpiperidinylmagnesium chloride lithium chloride complex)with Lewis acid AlCl_(3),we successfully synthesized an efficient amino-magnesium halide TMPLA electrolyte.Raman and mass spectroscopy identified that the electrolyte comprises the typical di-nuclear copolymer[Mg_(2)Cl_(3)·6THF]+cation group and[(TMP)2AlCl_(2)]-anion group,further supported by the results of density functional theory calculations(DFT)and the Molecular dynamics(MD)simulations.The TMPLA electrolyte exhibits promising electrochemical performance,including available anodic stability(>2.65 V vs.SS),high ionic conductivity(6.05mS cm^(-1)),and low overpotential(<0.1 V)as well as appropriate Coulombic efficiency(97.3%)for Mg plating/stripping.Both the insertion Mo6S8cathode and conversion Cu S cathode delivered a desirable electrochemical performance with high capacity and good cycling stability based on the TMPLA electrolyte.In particular,when compatible with low cost and easily synthesized Cu S,the Cu S||Mg cell displayed an extremely high discharge capacity of 458.8 mAh g^(-1)for the first cycle and stabilized at 170.2 mAh g^(-1)with high Coulombic efficiency(99.1%)after 50 cycles at 0.05 C.Our work proposes an efficient electrolyte with impressive compatibility with Mg anode and insertion/conversion cathode for practical RMBs and provides a more profound knowledge of the Lewis acid–base reaction mechanisms.
基金Natural Science Foundation of China(21501010,21231002,21671019)the 111 Project(B07012)for financial support.
文摘A new Ce^(3+)modified Dawson-like polyoxometalate cluster(C_(2)H_(8)N)_(12)Na_(2)[H_(10){Ce(H_(2)O)_(5)}_(2)(Te_(2)W_(37)O_(132))]·^(39)H_(2)O was synthesized using pH and temperature-controlled one-pot strategy.The compound was characterized by single-crystal X-ray structure analysis,IR spectroscopy,thermogravimetric(TG)analysis,X-ray photoelectron spectroscopy(XPS),and electrospray ionization mass spectrometry(ESI-MS).Singlecrystal X-ray structure analysis revealed that there was a new{Te_(2)W_(37)O_(132)}structure and two Ce^(3+)in this compound.Moreover,it is notable that this compound presents excellent Lewis acid-and Lewis base activities in the condensation cyclization of 1,3-diketones with hydrazines/hydrazides or diamines.All the desired products were obtained in moderate to good yields(up to 99%)and with a high turnover number(up to 4347).
基金financial support from the National Natural Science Foundation of China(Grant numbers 22439001,52172198,51902117)the China Postdoctoral Science Foundation(Grant number BX20240123)the Fundamental Research Funds for the Central Universities(Grant number HUST:2024JYCXJJ043)。
文摘The stacking of multiple defect-rich grain boundaries(GBs)along the long transportation path(~3μm)of charge carriers in printable mesoscopic perovskite solar cells(p-MPSCs)impedes their power conversion efficiency(PCE).Organic Lewis bases are widely utilized for defect passivation at GBs,but how their passivation efficiency affects energy loss remains unclear.Here we employed triphenylphosphine(TPP)and triphenylphosphine oxide(TPPO)as the model passivators in p-MPSCs.TPPO has a more negatively charged center than TPP,which enables its stronger coordination with one of the most common and detrimental defects at the GBs—undercoordinated lead.When added into the perovskite with the same ratio,TPPO passivates defects more significantly and thus less TPPO remaining inactive compared with TPP.Inactive organic passivators accumulated at the GBs could impose barriers to charge carrier transportation.Indeed,TPPO improves the device performance more significantly with a champion PCE of 20.54%achieved.Besides,the TPPO devices demonstrate excellent stability with 95%of initial PCE remaining after 600 h of maximum power point tracking at(55±5)℃.
基金supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Education(2020R1F1A1067763).
文摘Despite its great potential in supramolecular chemistry to achieve structural complexity and sophisticated functionality,the kinetic control over molecular self-assembly in coordination with supramolecular polymerization still constitutes a challenge.Herein,the kinetically controlled supramolecular polymerization of porphyrin derivatives was achieved in aqueous media by a seeding method based on a metastable state generated by synergistic metalation and Lewis acid–base complexation.
基金the National Natural Science Foundation of China(Nos.82073997 and 22001024)the Science&Technology Department of Sichuan Province(Nos.2021YFS0044 and 2021YJ0402)+1 种基金Innovation Team and Talents Cultivation Program of National Administration of Traditional Chinese Medicine(No.ZYYCXTD-D-202209)Xinglin Scholar Research Promotion Project of Chengdu University of TCM.
文摘The scope of stereochemistry recognition usually occurs near the chiral scaffold of a ligand or catalyst.Remote stereocontrol,which can surpass the limits of stereorecognition of remote prochiral centers,has long been a challenging object of great interest in asymmetric catalysis.The current work realized the remote stereocontrol of 1,7-zwitterion intermediates formed from Huang's o-amino aryl MBH carbonates.With simple and easily accessibleβ-ICD as the bifunctional catalyst,multifunctionalized tetrahydroquinoline derivatives could be synthesized via(4+2)cycloadditions with excellent enantioselectivity and diastereoselectivity under mild conditions.The strategy possesses broad substrate scope,and three types of electron-deficient enones are successfully applied.Mechanistic studies disclosed the Lewis base-catalyzed reaction pathway,and H-bonding between the catalyst and enones is crucial for long-range stereocontrol.Scale-up reaction and transformations of the tetrahydroquinoline products demonstrated the potential of this strategy.
