An enantiopure helical coordination polymer AgPF6·（R）-3 as crystalline solid was synthesized by the self-assembly of chiral binaphthyl-based ligand（R）-6,6＇-di[6-（2,2＇-bipyridyl）]-2,2＇-diethoxyl-1,1＇-bin...An enantiopure helical coordination polymer AgPF6·（R）-3 as crystalline solid was synthesized by the self-assembly of chiral binaphthyl-based ligand（R）-6,6＇-di[6-（2,2＇-bipyridyl）]-2,2＇-diethoxyl-1,1＇-binaphthalene [（R）-3] and Ag＋ ion.The single crystal structural analysis indicates that this polymer exhibits an infinite cylindric single-stranded M-helical structure with local Λ configuration at each tetrahedral metal center.However,the extended structure is dissociated into some oligomeric fragments in solution.The 1H NMR spectra of complex AgPF6·（R）-3 show that the ligand possesses a good C2 symmetry,and the chemical shifts of the protons depend on the concentration and temperature.In addition,there are rapid dynamic exchanges among some oligonuclear fragments in the solution of AgPF6·（R）-3.展开更多
A number of salen-metal complexes were prepared and their enantioselective catalytic properties toward the asymmetric iodolactonization of （E）- and （Z）-5-substituted-4-pentenoic acid derivatives were investigated....A number of salen-metal complexes were prepared and their enantioselective catalytic properties toward the asymmetric iodolactonization of （E）- and （Z）-5-substituted-4-pentenoic acid derivatives were investigated. The catalyst system based on salen-Co（II） complex exhibited moderate to good enantioselectivity with the e.e. value ranging from 53% to 74%, as well as high regioselectivity of δ- vs. γ-iodolactones. The salen-Co（II） complex showed the highest enantioselectivity on the asymmetric iodolactonizations of （Z）-5-substituted-4-pentenoic acid derivatives among these reagent-controlled iodolactonization protocols known so far.展开更多
A novel sulfonated diamine monomer, 4,6-bis（4-arninophenoxy）-naphthalene-2-sulfonic acid（BAPNS）, was synthesized. A series of sulfonated polyimide copolymers was prepared from BAPNS, 1,4,5,8-naphthalenetetracarbox...A novel sulfonated diamine monomer, 4,6-bis（4-arninophenoxy）-naphthalene-2-sulfonic acid（BAPNS）, was synthesized. A series of sulfonated polyimide copolymers was prepared from BAPNS, 1,4,5,8-naphthalenetetracarboxylic dianhydride（NTDA） and nonsulfonated diamine 4,4＇-diaminodiphenyl ether（ODA）. Flexible, transparent, and mechanically strong membranes were obtained. The novel sulfonated polyimide（SPI） membranes show higher conductivity, for example, SPI-100 shows a conductivity of 0.0698 S/cm at 80℃（SPI-X： Xrefers to molar fraction of BAPNS）. The membranes exhibit the permeability of methanol from 2.18×10^-7 cm2/s to 2.57×10^-7 cm2/s, which is much lower than that of Nafion（2.00×10 6 cm^2/s）. The copolymers were thermally stable up to 330℃. The sulfonated polyimide copolymers also show reasonable mechanical strength; for example, the maximum tensile strength at break of the sulfonated polyimide copolymer with 100%（molar fraction） BAPNS is 1.35 GPa under high moisture condi- tions. The optimum concentration of BAPNS was found to be 100%（molar fraction） from the view point of proton conductivity, methanol permeability, and membrane stability.展开更多
基金Supported by the National Natural Science Foundation of China(No.20502024)
文摘An enantiopure helical coordination polymer AgPF6·（R）-3 as crystalline solid was synthesized by the self-assembly of chiral binaphthyl-based ligand（R）-6,6＇-di[6-（2,2＇-bipyridyl）]-2,2＇-diethoxyl-1,1＇-binaphthalene [（R）-3] and Ag＋ ion.The single crystal structural analysis indicates that this polymer exhibits an infinite cylindric single-stranded M-helical structure with local Λ configuration at each tetrahedral metal center.However,the extended structure is dissociated into some oligomeric fragments in solution.The 1H NMR spectra of complex AgPF6·（R）-3 show that the ligand possesses a good C2 symmetry,and the chemical shifts of the protons depend on the concentration and temperature.In addition,there are rapid dynamic exchanges among some oligonuclear fragments in the solution of AgPF6·（R）-3.
文摘A number of salen-metal complexes were prepared and their enantioselective catalytic properties toward the asymmetric iodolactonization of （E）- and （Z）-5-substituted-4-pentenoic acid derivatives were investigated. The catalyst system based on salen-Co（II） complex exhibited moderate to good enantioselectivity with the e.e. value ranging from 53% to 74%, as well as high regioselectivity of δ- vs. γ-iodolactones. The salen-Co（II） complex showed the highest enantioselectivity on the asymmetric iodolactonizations of （Z）-5-substituted-4-pentenoic acid derivatives among these reagent-controlled iodolactonization protocols known so far.
文摘A novel sulfonated diamine monomer, 4,6-bis（4-arninophenoxy）-naphthalene-2-sulfonic acid（BAPNS）, was synthesized. A series of sulfonated polyimide copolymers was prepared from BAPNS, 1,4,5,8-naphthalenetetracarboxylic dianhydride（NTDA） and nonsulfonated diamine 4,4＇-diaminodiphenyl ether（ODA）. Flexible, transparent, and mechanically strong membranes were obtained. The novel sulfonated polyimide（SPI） membranes show higher conductivity, for example, SPI-100 shows a conductivity of 0.0698 S/cm at 80℃（SPI-X： Xrefers to molar fraction of BAPNS）. The membranes exhibit the permeability of methanol from 2.18×10^-7 cm2/s to 2.57×10^-7 cm2/s, which is much lower than that of Nafion（2.00×10 6 cm^2/s）. The copolymers were thermally stable up to 330℃. The sulfonated polyimide copolymers also show reasonable mechanical strength; for example, the maximum tensile strength at break of the sulfonated polyimide copolymer with 100%（molar fraction） BAPNS is 1.35 GPa under high moisture condi- tions. The optimum concentration of BAPNS was found to be 100%（molar fraction） from the view point of proton conductivity, methanol permeability, and membrane stability.
