Because of their unique structural and chemical properties,buckybowl molecules have attracted considerable attention in a wide range of scientific disciplines.The importance and utility of buckybowl molecules signific...Because of their unique structural and chemical properties,buckybowl molecules have attracted considerable attention in a wide range of scientific disciplines.The importance and utility of buckybowl molecules significantly increases once they acquire largerπ-surface area and/or heteroatoms.The fusion of buckybowl molecules has emerged as a new strategy to extend theπ-surface of polycyclic aromatic compounds;however,theπ-extension of heteroatom-embedded buckybowls by the fusion strategy is still rare.Here we report the synthesis and propeties of a fused azacorannulene dimer bearing a C62N2 core(1a),which can also be regarded as a double aza[5]helicene.Due to the steric repulsion between two azapentabenzocorannulene moieties,this molecule shows a rigid S-shaped structure where the two azacorannulene bowls face in opposite directions.Stepwise chemical oxidation of 1a resulted in the formation of the corresponding radical cation(1a^(+))and dication(1a^(2+)),providing an important insight into their aromaticity.The fusion of heteroatom-embedded buckybowls provides a powerful way to synthesizeπ-extended polycyclic aromatic molecules.展开更多
Regio-and stereoselective 1,3-dipolar cycloadditions of C-(3-indolyl)-N-phenylnitrone(10)were carried out with different mono-substituted,disubstituted and cyclic dipolarophiles under mono-mode microwave irradiation t...Regio-and stereoselective 1,3-dipolar cycloadditions of C-(3-indolyl)-N-phenylnitrone(10)were carried out with different mono-substituted,disubstituted and cyclic dipolarophiles under mono-mode microwave irradiation to obtain substituted 3-(indol-30-yl)-N-phenyl-isoxazolidines(16–22).Reactions of nitrone(10)with allenic esters under similar conditions afforded,via a domino process,bis-indole derivatives(23a–c)along with compounds 24 and 25.Similarly,reactions of C-(3-pyridyl)-N-phenylnitrone(26)with mono-substituted,disubstituted and cyclic dipolarophiles were carried out in refluxing dry toluene to obtain substituted 3-(30-pyridyl)-Nphenylisoxazolidines(27–34).Some of the compounds(16f,18b,23a,23c,27c and 29f)display significant cytotoxicity against a number of human cancer cell lines.展开更多
A highly efficient and mild method for[3 t 2]cycloaddition ofβ-sulfonyl-α,β-unsaturated ketones with terminal allenoates was well-explored and developed.The reactions were successfully performed by applying multifu...A highly efficient and mild method for[3 t 2]cycloaddition ofβ-sulfonyl-α,β-unsaturated ketones with terminal allenoates was well-explored and developed.The reactions were successfully performed by applying multifunctional chiral phosphine P6 which was screened from eight chiral phosphorus reagents to finally result in a variety of enantioenriched sulfone-substituted cyclopentenes with two chiral centers(up to 81%yield with 94%ee).Moreover,2.5 mol%catalytic equivalents were proved to be feasible when this reaction was performed on a 10 mmol scale.展开更多
In the presence of room temperature ionic liquids based on 1 butyl 3 methylimidazolium salt and butylpyridinium salt, cycloaddition of propylene oxide and carbon dioxide without any additional organic solvents was inv...In the presence of room temperature ionic liquids based on 1 butyl 3 methylimidazolium salt and butylpyridinium salt, cycloaddition of propylene oxide and carbon dioxide without any additional organic solvents was investigated. It was found that both cations and anions of the room temperature ionic liquids have strong influence on the catalytic activity. The better catalytic performance was achieved with 1 butyl 3 methylimidazolium tetrafluoroborate as a catalyst. A suitable CO 2/propylene oxide molar ratio is needed for the reaction, and the conversion of propylene oxide increases with the increase of reaction temperature. The ionic liquid as a catalyst for such reaction can be recycled.展开更多
In the presence of Dawson-type polyoxotungstate, α 2-[(n-C 4H 9) 4] (11-n)P 2W 17O 61(M n+·Br)[abbreviated as P 2W 17M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(n-C 4H 9) 4N] 6P 2W 18O 62(abbreviated as...In the presence of Dawson-type polyoxotungstate, α 2-[(n-C 4H 9) 4] (11-n)P 2W 17O 61(M n+·Br)[abbreviated as P 2W 17M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(n-C 4H 9) 4N] 6P 2W 18O 62(abbreviated as P 2W 18), cycloaddition reaction of carbon dioxide to propylene oxide were studied under moderate reaction conditions without any additional organic solvents. The experimental results indicated that the synthesis of propylene carbonate was completed in 98% yield and 100% selectivity by using {P 2W 17Co·Br} as the catalyst, while the P 2W 18 complex showed the lowest catalytic activity with less than 1% yield of propylene carbonate. The dependency of the catalytic activity on transition metal of mono-substituted polyoxometalate, P 2W 17M·Br, as well as the nucleophilicity of the bromide ion was concluded from the process analysis.展开更多
A modified silicon-containing arylacetylene resin with a well-defined organic-inorganic POSS functionality was successfully synthesized by Huisgen azide-alkyne 1,3-dipolar cycloaddition. The POSS hybridized resin exhi...A modified silicon-containing arylacetylene resin with a well-defined organic-inorganic POSS functionality was successfully synthesized by Huisgen azide-alkyne 1,3-dipolar cycloaddition. The POSS hybridized resin exhibits excellent thermal properties which were characterized by differential scanning calorimetry （DSC） and thermogravimetric analyses （TGA）. Scanning electron microscope （SEM） was used to characterize fracture surface of the hybridized polymer. The results show that phase separation occurs. The POSS moieties are aggregated each other in the polymer to form 200-400 nm domains.展开更多
The aim of ＂green chemistry＂ and ＂atom economy＂ is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts inclu...The aim of ＂green chemistry＂ and ＂atom economy＂ is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts including organic bases, ionic liquids, supported catalysts, organic copolymers and carbon materials for the synthesis of cyclic carbonates by the cycloaddition of carbon dioxide to epoxides are reviewed. Recent advances in the design of the catalysts and the understanding of the reaction mechanism are summarized and discussed. The synergistic effects of organic bases and hydrogen bond donors, organic bases and nucleophilic anions, hydrogen bond donors and nucleophilic anions and active components and supports are highlighted. The challenge is to develop metal-free catalysts suitable for carbon dioxide capture and fixation. The ultimate goal is to synthesize cyclic carbonates in a flow reactor directly using carbon dioxide from industrial flue gas at ambient temperature and atmospheric pressure. By using synergetic effects, a multi-functional approach can meet the design strategy of metal-free catalysts for carbon dioxide adsorption and activation as well as epoxide ring opening.展开更多
Global warming and climate change due to anthropogenic carbon dioxide(CO_(2))have aroused significant concerns at the global scale due to rapid economic growth in industries and other fields.Therefore,CO_(2)capture,us...Global warming and climate change due to anthropogenic carbon dioxide(CO_(2))have aroused significant concerns at the global scale due to rapid economic growth in industries and other fields.Therefore,CO_(2)capture,use,and storage have become particularly important.In this review,general background and methods for CO_(2)capture and separation,in particular,on ionic liquids(ILs)-based solvents and materials,are discussed.Comprehensive surveys of ILs for CO_(2)absorption are presented,which focused mainly on experimental researches,and then the concept is extended to functionalized absorbents and recent developments for CO_(2)capture.Major advantages and disadvantages of amines-based and ILs-based absorbents are discussed in this review.Solutions of traditional amines(MEA,MDEA,DEA,AMP,PZ,etc.)and ILs(conventional ILs,functionalized ILs,etc.)are summarized.Moreover,research progresses on CO_(2)separation are also introduced focusing mainly on amines and ILs-based membranes(e.g.supported amines membranes,SILMs).Futhermore,the fixation of CO_(2)into cyclic carbonates catalyzed by ILs(pure ILs,complex catalyst system with ILs,supported ILs,etc.)is summarized,clearly explaining the mechanism of CO_(2)fixation with ILs.Finally,exploration of some recent studies about CO_(2)capture and conversion by ILs and challenges for further progress are presented and related suggestions are put forward.展开更多
文摘Because of their unique structural and chemical properties,buckybowl molecules have attracted considerable attention in a wide range of scientific disciplines.The importance and utility of buckybowl molecules significantly increases once they acquire largerπ-surface area and/or heteroatoms.The fusion of buckybowl molecules has emerged as a new strategy to extend theπ-surface of polycyclic aromatic compounds;however,theπ-extension of heteroatom-embedded buckybowls by the fusion strategy is still rare.Here we report the synthesis and propeties of a fused azacorannulene dimer bearing a C62N2 core(1a),which can also be regarded as a double aza[5]helicene.Due to the steric repulsion between two azapentabenzocorannulene moieties,this molecule shows a rigid S-shaped structure where the two azacorannulene bowls face in opposite directions.Stepwise chemical oxidation of 1a resulted in the formation of the corresponding radical cation(1a^(+))and dication(1a^(2+)),providing an important insight into their aromaticity.The fusion of heteroatom-embedded buckybowls provides a powerful way to synthesizeπ-extended polycyclic aromatic molecules.
文摘Regio-and stereoselective 1,3-dipolar cycloadditions of C-(3-indolyl)-N-phenylnitrone(10)were carried out with different mono-substituted,disubstituted and cyclic dipolarophiles under mono-mode microwave irradiation to obtain substituted 3-(indol-30-yl)-N-phenyl-isoxazolidines(16–22).Reactions of nitrone(10)with allenic esters under similar conditions afforded,via a domino process,bis-indole derivatives(23a–c)along with compounds 24 and 25.Similarly,reactions of C-(3-pyridyl)-N-phenylnitrone(26)with mono-substituted,disubstituted and cyclic dipolarophiles were carried out in refluxing dry toluene to obtain substituted 3-(30-pyridyl)-Nphenylisoxazolidines(27–34).Some of the compounds(16f,18b,23a,23c,27c and 29f)display significant cytotoxicity against a number of human cancer cell lines.
基金The authors are grateful to NSFC(Nos.21971066 and 21772042)for financial support.Special thanks to profJunliang Zhang(Fudan University)for his kind suggestion on this[3 t 2]cycloaddition reaction.
文摘A highly efficient and mild method for[3 t 2]cycloaddition ofβ-sulfonyl-α,β-unsaturated ketones with terminal allenoates was well-explored and developed.The reactions were successfully performed by applying multifunctional chiral phosphine P6 which was screened from eight chiral phosphorus reagents to finally result in a variety of enantioenriched sulfone-substituted cyclopentenes with two chiral centers(up to 81%yield with 94%ee).Moreover,2.5 mol%catalytic equivalents were proved to be feasible when this reaction was performed on a 10 mmol scale.
文摘In the presence of room temperature ionic liquids based on 1 butyl 3 methylimidazolium salt and butylpyridinium salt, cycloaddition of propylene oxide and carbon dioxide without any additional organic solvents was investigated. It was found that both cations and anions of the room temperature ionic liquids have strong influence on the catalytic activity. The better catalytic performance was achieved with 1 butyl 3 methylimidazolium tetrafluoroborate as a catalyst. A suitable CO 2/propylene oxide molar ratio is needed for the reaction, and the conversion of propylene oxide increases with the increase of reaction temperature. The ionic liquid as a catalyst for such reaction can be recycled.
文摘In the presence of Dawson-type polyoxotungstate, α 2-[(n-C 4H 9) 4] (11-n)P 2W 17O 61(M n+·Br)[abbreviated as P 2W 17M·Br, M=Co(Ⅱ), Mn(Ⅲ), Cu(Ⅱ)] and saturated [(n-C 4H 9) 4N] 6P 2W 18O 62(abbreviated as P 2W 18), cycloaddition reaction of carbon dioxide to propylene oxide were studied under moderate reaction conditions without any additional organic solvents. The experimental results indicated that the synthesis of propylene carbonate was completed in 98% yield and 100% selectivity by using {P 2W 17Co·Br} as the catalyst, while the P 2W 18 complex showed the lowest catalytic activity with less than 1% yield of propylene carbonate. The dependency of the catalytic activity on transition metal of mono-substituted polyoxometalate, P 2W 17M·Br, as well as the nucleophilicity of the bromide ion was concluded from the process analysis.
文摘A modified silicon-containing arylacetylene resin with a well-defined organic-inorganic POSS functionality was successfully synthesized by Huisgen azide-alkyne 1,3-dipolar cycloaddition. The POSS hybridized resin exhibits excellent thermal properties which were characterized by differential scanning calorimetry （DSC） and thermogravimetric analyses （TGA）. Scanning electron microscope （SEM） was used to characterize fracture surface of the hybridized polymer. The results show that phase separation occurs. The POSS moieties are aggregated each other in the polymer to form 200-400 nm domains.
基金supported by the National Science and Technology Support Project of China(2013BAC11B03)the National Natural Science Foundation of China(21401054,21476065,21273067)the Graduate Student Scientific Research Innovation Fund Project of Hunan Province(CX2015B082)~~
文摘The aim of ＂green chemistry＂ and ＂atom economy＂ is to utilize carbon dioxide and replace harmful reactants such as CO and phosgene for the production of cyclic carbonates. In this paper, metal-free catalysts including organic bases, ionic liquids, supported catalysts, organic copolymers and carbon materials for the synthesis of cyclic carbonates by the cycloaddition of carbon dioxide to epoxides are reviewed. Recent advances in the design of the catalysts and the understanding of the reaction mechanism are summarized and discussed. The synergistic effects of organic bases and hydrogen bond donors, organic bases and nucleophilic anions, hydrogen bond donors and nucleophilic anions and active components and supports are highlighted. The challenge is to develop metal-free catalysts suitable for carbon dioxide capture and fixation. The ultimate goal is to synthesize cyclic carbonates in a flow reactor directly using carbon dioxide from industrial flue gas at ambient temperature and atmospheric pressure. By using synergetic effects, a multi-functional approach can meet the design strategy of metal-free catalysts for carbon dioxide adsorption and activation as well as epoxide ring opening.
基金the Key Research and Development Project of Ningxia(2018BDE02057)the National Natural Science Foundation of China(219911100,219911101)for this work.
文摘Global warming and climate change due to anthropogenic carbon dioxide(CO_(2))have aroused significant concerns at the global scale due to rapid economic growth in industries and other fields.Therefore,CO_(2)capture,use,and storage have become particularly important.In this review,general background and methods for CO_(2)capture and separation,in particular,on ionic liquids(ILs)-based solvents and materials,are discussed.Comprehensive surveys of ILs for CO_(2)absorption are presented,which focused mainly on experimental researches,and then the concept is extended to functionalized absorbents and recent developments for CO_(2)capture.Major advantages and disadvantages of amines-based and ILs-based absorbents are discussed in this review.Solutions of traditional amines(MEA,MDEA,DEA,AMP,PZ,etc.)and ILs(conventional ILs,functionalized ILs,etc.)are summarized.Moreover,research progresses on CO_(2)separation are also introduced focusing mainly on amines and ILs-based membranes(e.g.supported amines membranes,SILMs).Futhermore,the fixation of CO_(2)into cyclic carbonates catalyzed by ILs(pure ILs,complex catalyst system with ILs,supported ILs,etc.)is summarized,clearly explaining the mechanism of CO_(2)fixation with ILs.Finally,exploration of some recent studies about CO_(2)capture and conversion by ILs and challenges for further progress are presented and related suggestions are put forward.
