A ladder-like structure compound formed by cadmium (II) and anionic nitronyl nitroxide, [Cd2(NITpBA)4(H2O)4] (where NITpBA = 2-(4-carboxyphenyl)4,4,5,5-tetramethyl-4,5-dihydro-imidazol-1-oxyl-3-oxide), has been synthe...A ladder-like structure compound formed by cadmium (II) and anionic nitronyl nitroxide, [Cd2(NITpBA)4(H2O)4] (where NITpBA = 2-(4-carboxyphenyl)4,4,5,5-tetramethyl-4,5-dihydro-imidazol-1-oxyl-3-oxide), has been synthesized and characterized. X-ray analysis reveals that the compound 1 crystallizes in the monoclinic P21/c (No. 14) space group, and [Cd2(NITpBA)4(H2O)4] units are linked into infinite chains by radical bridging ligands.展开更多
The optically active polymers of (-) menthyl methacrylate were obtained by anionic, group transfer polymerization(GTP) and radical polymerization methods. The influences of different polymerization methods on specific...The optically active polymers of (-) menthyl methacrylate were obtained by anionic, group transfer polymerization(GTP) and radical polymerization methods. The influences of different polymerization methods on specific rotation, yield and stereoregularity of polymers were studied. In the fluorene lithium and ( S,S ) (+) 2,3 dimethoxy 1,4 bis(dimethylamino)butane complex initiative system, the specific rotation values rise slightly with the increase of molecular weight. There is no obvious difference in the specific rotation values of PMnMAs obtained by different polymerization methods, but there is an obvious variation in stereoregularity of the polymers. And the change of the optical activity of PMnMA is slight as compared with the variation of the stereoregularity. The tacticity of polymers is mainly syndiotactic.展开更多
The precise synthesis of polymer with narrow molecular weight distribution(?)and well-defined architectures is very essential to exploring the functions and properties of polymer materials.Here,a universal polymerizat...The precise synthesis of polymer with narrow molecular weight distribution(?)and well-defined architectures is very essential to exploring the functions and properties of polymer materials.Here,a universal polymerization method capable of low?and reactive hydrogen compatibility is reported by introducing super-Grignard reagents(R_(2)Mg?Li Cl)into polymer chemistry.Under mild conditions,various monomers,including nonpolar polystyrene and 4-methoxystyrene that cannot be initiated by Grignard reagents,and polar methacrylate,are successfully polymerized with full monomer conversion and low?.This approach is amenable to wide varieties of initiators,polymerization temperature,and feed ratio,which makes it attractive for applications in polymer synthesis.By adding methanol and water during the polymerization process,the reactive hydrogen compatibility of this method is confirmed,which makes this method avoid the rigorous restriction on polymerization conditions of anionic polymerization.Moreover,chain extension polymerization and block copolymerization are achieved and demonstrate the livingness of chain propagation,enabling the facile synthesis of well-defined macromolecular architectures.This work therefore expands the methodology libraries of living polymerization,which may cause inspirations to polymer science.展开更多
Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene) oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as in...Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene) oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as initiator. Then the PS-CH2CH2OCOCCl3 (PS-Cl-3) or P(S-b-B)-CH2CH2O-COCCl3 (PSB-Cl-3) was used as the macroinitiator in the polymerization of(meth)acrylates in the presence of CuX/bpy. AB diblock and ABC triblock copolymers were prepared by the integrated living anionic polymerization (LAP)-atom transfer radical polymerization (ATRP). The structures of the PSB-Cl-3 and the P(S-b-MMA) were identified by FTIR and H-1-NMR spectrum, respectively. A new way to design block copolymers (the combination of LAP and ATRP) was developed.展开更多
A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The...A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The synthetic approach involves the coupling reaction of polystyrene(PS) backbone bearing 1,1-diphenylethene(DPE) pendant groups,produced by ATRP and Wittig reaction,with living polystyryllithium(PSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMR,IR,SEC,SLS,and DSC measurements.展开更多
文摘A ladder-like structure compound formed by cadmium (II) and anionic nitronyl nitroxide, [Cd2(NITpBA)4(H2O)4] (where NITpBA = 2-(4-carboxyphenyl)4,4,5,5-tetramethyl-4,5-dihydro-imidazol-1-oxyl-3-oxide), has been synthesized and characterized. X-ray analysis reveals that the compound 1 crystallizes in the monoclinic P21/c (No. 14) space group, and [Cd2(NITpBA)4(H2O)4] units are linked into infinite chains by radical bridging ligands.
文摘The optically active polymers of (-) menthyl methacrylate were obtained by anionic, group transfer polymerization(GTP) and radical polymerization methods. The influences of different polymerization methods on specific rotation, yield and stereoregularity of polymers were studied. In the fluorene lithium and ( S,S ) (+) 2,3 dimethoxy 1,4 bis(dimethylamino)butane complex initiative system, the specific rotation values rise slightly with the increase of molecular weight. There is no obvious difference in the specific rotation values of PMnMAs obtained by different polymerization methods, but there is an obvious variation in stereoregularity of the polymers. And the change of the optical activity of PMnMA is slight as compared with the variation of the stereoregularity. The tacticity of polymers is mainly syndiotactic.
基金funding support from National Natural Science Foundation of China(NSFC,Nos.22271286 and 21971236)the Haixi Institute of CAS(No.CXZX-2017-P01)。
文摘The precise synthesis of polymer with narrow molecular weight distribution(?)and well-defined architectures is very essential to exploring the functions and properties of polymer materials.Here,a universal polymerization method capable of low?and reactive hydrogen compatibility is reported by introducing super-Grignard reagents(R_(2)Mg?Li Cl)into polymer chemistry.Under mild conditions,various monomers,including nonpolar polystyrene and 4-methoxystyrene that cannot be initiated by Grignard reagents,and polar methacrylate,are successfully polymerized with full monomer conversion and low?.This approach is amenable to wide varieties of initiators,polymerization temperature,and feed ratio,which makes it attractive for applications in polymer synthesis.By adding methanol and water during the polymerization process,the reactive hydrogen compatibility of this method is confirmed,which makes this method avoid the rigorous restriction on polymerization conditions of anionic polymerization.Moreover,chain extension polymerization and block copolymerization are achieved and demonstrate the livingness of chain propagation,enabling the facile synthesis of well-defined macromolecular architectures.This work therefore expands the methodology libraries of living polymerization,which may cause inspirations to polymer science.
基金The Project is supported by the National Natural Science Foundation of China (Grant No. 29634010-2), Shanghai Education Development Foundation Shuguang Program (Project SG97008) and Research Institute of Beijing Yanshan Petrochemical Corporation.
文摘Alpha-trichloroacetoxy terminated polystyrene oligomer (PS-CH2CH2OCOCCl3) and poly-(styrene-b-butadiene) oligomer [P(S-b-B)-CH2CH2OCOCCl3)] were synthesized by living anionic polymeri-zation using n-butyllithium as initiator. Then the PS-CH2CH2OCOCCl3 (PS-Cl-3) or P(S-b-B)-CH2CH2O-COCCl3 (PSB-Cl-3) was used as the macroinitiator in the polymerization of(meth)acrylates in the presence of CuX/bpy. AB diblock and ABC triblock copolymers were prepared by the integrated living anionic polymerization (LAP)-atom transfer radical polymerization (ATRP). The structures of the PSB-Cl-3 and the P(S-b-MMA) were identified by FTIR and H-1-NMR spectrum, respectively. A new way to design block copolymers (the combination of LAP and ATRP) was developed.
基金Supported by the National Natural Science Foundation of China (Grant No. 20304005)Senior Foundation of Key Laboratory in Fudan University
文摘A well-defined,A2B-type,centipede-like copolymer of styrene and methyl methacrylate(PS-PS-PMMA) was synthesized by the combination of living anionic polymerization and atom transfer radical polym-erization(ATRP) . The synthetic approach involves the coupling reaction of polystyrene(PS) backbone bearing 1,1-diphenylethene(DPE) pendant groups,produced by ATRP and Wittig reaction,with living polystyryllithium(PSLi) ,and subsequent polymerization of the resulting 1,1-diphenylmethyl anions with methy methacrylate. The centipede-like copolymer was characterized by 1H NMR,IR,SEC,SLS,and DSC measurements.
