In this paper, (-)menthyl methacrylate((-)MnMA) was polymerized at 78C in toluene with three types of anionic catalysts, which were complexes of fluorenyllithium with (-)sparteine - ((-)-Sp) , (S, S)-(+)-2, 3-dimethox...In this paper, (-)menthyl methacrylate((-)MnMA) was polymerized at 78C in toluene with three types of anionic catalysts, which were complexes of fluorenyllithium with (-)sparteine - ((-)-Sp) , (S, S)-(+)-2, 3-dimethoxy-1, 4-bis(dimethylamino)butane((+)DDB) and N,N,N,N-tetra- methylethylenediamine(TMEDA), and the chiral optical property of the obtained polymer was studied. The circular dichroism (CD) spectrum of the polymer showed negative Cotton effect.展开更多
The fluorescence spectra of the poly (N-vinylcarbazole) in solution obtained with chirally organic salts or acid as catalyst or initiator [ (-)Sp: (-)-Sparteine, (+)CSA: D- (+)Camphor-10-sulfonic acid)], respectively,...The fluorescence spectra of the poly (N-vinylcarbazole) in solution obtained with chirally organic salts or acid as catalyst or initiator [ (-)Sp: (-)-Sparteine, (+)CSA: D- (+)Camphor-10-sulfonic acid)], respectively, have been investigated. It is found that the two emission peaks at the longer wavelength (lambda max, ca, 415nm) and the shorter wavelength (lambda max, ca, 370nm) are assigned to the sandwich excimer and second excimer (partial overlap) fluorescence, respectively. The sandwich excimer and partially overlapped excimer are attributed to a fully overlapped structure of neighbouring carbazole chromophores in a totally elipsed conformation of the isotactic sequence, and partially overlapped structure of the syndiotactic sequence. The estimated values of I-415/I-370 and isotactic sequence content by using the fluorescence spectra are in the order: (-)Sp(+) (+)CSA(-)> (+)CSA(-)> (-)Sp(+)ClO(4)(-) (no peak at 415nm for AIBN).展开更多
Chiral-polymers with metal-coordination ability showgreat potential formediating asymmetric reactions.However,the synthesis of structurally diverse chiral polymers remains a great challenge,especially doing so efficie...Chiral-polymers with metal-coordination ability showgreat potential formediating asymmetric reactions.However,the synthesis of structurally diverse chiral polymers remains a great challenge,especially doing so efficiently.Herein,four types of Cucatalyzed multicomponent asymmetric polymerizationswere developed using a flexible combination of OBoc-alkyne.展开更多
The structure and properties of poly(N-vinylcarbazole) (PVCZ) obtained via asymmetrically stereoselective polymerization have been studied by using **1H NMR spectra, UV spectra, DSC analysis and GPC. The steric micro...The structure and properties of poly(N-vinylcarbazole) (PVCZ) obtained via asymmetrically stereoselective polymerization have been studied by using **1H NMR spectra, UV spectra, DSC analysis and GPC. The steric microstructure i.e. the content of isotactic sequences was found to be increased by using AIBN to ( minus )Sp***** plus ( plus )CSA***** minus as the initiators or catalysts and the mole extinction coefficient to be decreased. Bimodal molecular weight distribution (MWD)s of the obtained PVCZs were caused by two propagating species of the free ions and the ion-pairs associated with the organic salts during polymerization. (Author abstract) 19 Refs.展开更多
基金the National Natural Science Foundation of China for financial support
文摘In this paper, (-)menthyl methacrylate((-)MnMA) was polymerized at 78C in toluene with three types of anionic catalysts, which were complexes of fluorenyllithium with (-)sparteine - ((-)-Sp) , (S, S)-(+)-2, 3-dimethoxy-1, 4-bis(dimethylamino)butane((+)DDB) and N,N,N,N-tetra- methylethylenediamine(TMEDA), and the chiral optical property of the obtained polymer was studied. The circular dichroism (CD) spectrum of the polymer showed negative Cotton effect.
文摘The fluorescence spectra of the poly (N-vinylcarbazole) in solution obtained with chirally organic salts or acid as catalyst or initiator [ (-)Sp: (-)-Sparteine, (+)CSA: D- (+)Camphor-10-sulfonic acid)], respectively, have been investigated. It is found that the two emission peaks at the longer wavelength (lambda max, ca, 415nm) and the shorter wavelength (lambda max, ca, 370nm) are assigned to the sandwich excimer and second excimer (partial overlap) fluorescence, respectively. The sandwich excimer and partially overlapped excimer are attributed to a fully overlapped structure of neighbouring carbazole chromophores in a totally elipsed conformation of the isotactic sequence, and partially overlapped structure of the syndiotactic sequence. The estimated values of I-415/I-370 and isotactic sequence content by using the fluorescence spectra are in the order: (-)Sp(+) (+)CSA(-)> (+)CSA(-)> (-)Sp(+)ClO(4)(-) (no peak at 415nm for AIBN).
基金supported by the National Science Foundation of China(No.21978039)Special Funds of the Central Government Guiding Local Science and Technology Development(Nos.2021JH6/10500148 and 2021JH6/10500146)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20211100)and the Fundamental Research Funds for the Central Universities(Nos.DUT20YG120 and DUT21YG133).
文摘Chiral-polymers with metal-coordination ability showgreat potential formediating asymmetric reactions.However,the synthesis of structurally diverse chiral polymers remains a great challenge,especially doing so efficiently.Herein,four types of Cucatalyzed multicomponent asymmetric polymerizationswere developed using a flexible combination of OBoc-alkyne.
基金Project 29774039 was supported by the National Natural Science Foundation of China
文摘The structure and properties of poly(N-vinylcarbazole) (PVCZ) obtained via asymmetrically stereoselective polymerization have been studied by using **1H NMR spectra, UV spectra, DSC analysis and GPC. The steric microstructure i.e. the content of isotactic sequences was found to be increased by using AIBN to ( minus )Sp***** plus ( plus )CSA***** minus as the initiators or catalysts and the mole extinction coefficient to be decreased. Bimodal molecular weight distribution (MWD)s of the obtained PVCZs were caused by two propagating species of the free ions and the ion-pairs associated with the organic salts during polymerization. (Author abstract) 19 Refs.
