共查询到20条相似文献,搜索用时 31 毫秒
1.
Yoshio Okamoto 《Journal of polymer science. Part A, Polymer chemistry》2009,47(7):1731-1739
In 1979, the formation of one‐handed helical poly(triphenylmethyl methacrylate) (PTrMA) was found through the helix‐sense‐selective polymerization of methacrylate using chiral anionic initiators, and the existence of a stable helical polymer without chiral side chains was proved. The chiral polymer exhibited unexpected high chiral recognition of various racemic compounds when used as the chiral packing material (CPM) for HPLC, which was commercialized in 1982 as the first chiral column based on an optically active polymer. This success encouraged us to develop further useful commercial chiral packing materials (CPMs) based on polysaccharides, cellulose, and amylose. By using these polysaccharide‐based CPMs, particularly phenylcarbamate derivatives, nearly 90% of chiral compounds can be resolved not only analytically but also preparatively, and several chiral drugs have been produced using the CPMs. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1731–1739, 2009 相似文献
2.
This note explains the relationship (as well as the absence of a relationship) between chiral space groups and chiral molecules (which have absolute configurations).For a chiral molecule,which must crystallize in a chiral space group,the outcome of the absolute configuration determination must be linked to some other properties of the chiral crystal such as its optical activity for the observation to the relevant. 相似文献
3.
LIYan-yun CHENJian-shan YANGChuan-bo DONGZhen-rong LIBao-zhu ZHANGHui GAOJing-xing TAKAOIkariya 《高等学校化学研究》2004,20(2):180-184
The efficient chiral Ru3(CO)12 systems were prepared in situ from Ru3(CO)12 and various chiral diiminoor diamino-diphosphine tetradentate ligands. The systems have been used for the asymmetric transfer hydrogenation of propiophenone in 2-propanol, leading to 1-phenyl-1-propanol in a 98% yield and 96% e.e. The IR study suggests that the carbonyl hydride anion [HRu3(CO)11]^- most probably exists as a principal species under the reaction conditions. The high chiral efficiency may be due to the synergetic effect produced by the neighboring ruthenium atoms and a special chiral micro-environment involving the polydentate ligand and the Ru3 framework. 相似文献
4.
Florian Ostler Dr. Dariusz G. Piekarski Tobias Danelzik Prof. Dr. Mark S. Taylor Prof. Dr. Olga García Mancheño 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(7):2315-2320
Halogen bonding represents a powerful tool in the field of noncovalent interactions. However, applications in enantioselective recognition and catalysis remain almost nonexistent, due in part to the distinct features of halogen bonds, including long covalent and noncovalent bond distances and high directionality. Herein, this work presents a novel chiral tetrakis-iodo-triazole structure as a neutral halogen bond donor for both chiral anion-recognition and enantioinduction in ion-pair organocatalysis. NMR-titration studies revealed significant differences in anion affinity between the halogen bonding receptor and its hydrogen bonding parent. Selective recognition of chiral dicarboxylates and asymmetric induction in a benchmark organocatalytic reaction were demonstrated using the halogen bond donor. Inversions in the absolute sense of chiral recognition, enantioselectivity, and chiroptical properties relative to the related hydrogen donor were observed. Computational modeling suggested that these effects were the result of distinct anion-binding modes for the halogen- versus hydrogen-bond donors. 相似文献
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6.
测定手性有机酸对映体纯度的新试剂 总被引:2,自引:0,他引:2
用NMR技术测定微量手性化合物的对映体纯度,已有多种方法。其中,加手性镧化物位移试剂法适用面最广,但对有机酸,结果常不理想。另一种使用较广的方法是加手性试剂,将样品中两对映体转变成非对映异构体,然后比较非对映基因NMR信号的强度,确定原样品中对映体的组成比例。国外已出售的手性试 相似文献
7.
Xiaopeng Feng Dr. Bowen Shen Bo Sun Dr. Jehan Kim Xin Liu Prof. Myongsoo Lee 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(28):11451-11455
Although considerable effort in recent years has been devoted to the development of two-dimensional nanostructures, single-layered chiral sheet structures with a lateral assembly of discrete clusters remain elusive. Here, we report single-layered chiral 2D sheet structures with dual chiral void spaces in which discrete clusters of planar aromatic segments are arranged with in-plane AB order in aqueous methanol solution. The chirality of the sheet is induced by the slipped-cofacial stacks of rectangular plate-like aromatic segments in the discrete clusters which are arranged laterally with up and down packing, resulting in dual chiral void spaces. The chiral nanosheets function as superfast enantiomer separation nanomaterials, which rapidly absorb a single enantiomer from a racemic mixture with greater than 99 % ee. 相似文献
8.
报道了一种手性金属有机笼[Cu12(LPA)12(H2O)12](PA=L-苯丙氨酸, MOC-PA)作为毛细管电泳分离新型固定相的研究. 采用X射线粉末衍射仪、 红外光谱、 热重分析和扫描电子显微镜对该材料进行了表征, 结果表明该手性金属有机笼具有良好的热稳定性和空间结构. 利用该材料制备的毛细管色谱柱具有良好的手性识别能力, 可拆分1,2-二苯基乙二醇、 佐匹克隆、 4-甲基二苯基甲醇和茴香偶姻等手性药物, 也能拆分位置异构体硝基苯酚. 通过对拆分1,2-二苯基乙二醇、 佐匹克隆、 4-甲基二苯基甲醇和茴香偶姻进行最佳条件的探究, 得出电压、 缓冲溶液浓度及pH值在毛细管电泳中对手性样品分离度的影响. 采用佐匹克隆进行毛细管柱的重现性研究表明, 用该材料制备的毛细管电泳色谱柱具有一定的稳定性和重现性. 可见, 金属有机笼是一种良好的毛细管电泳手性固定相, 有一定的手性拆分能力, 在色谱分离中有较好的发展前景. 相似文献
9.
Dr. Lu Zheng Yulin Zhan Lin Ye Dan Zheng Dr. Ying Wang Prof. Kun Zhang Prof. Hua Jiang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(62):14162-14168
Two pentameric foldamers, Q5 and Q5C-S , containing a C−F bond were synthesized based on quinoline oligamide foldamers for the measurement of enantiomeric excess and for the determination of absolute configuration of chiral amines, diamines, amino alcohols, and α-amino acid esters. Chiral induction of Q5 was triggered in situ when the chiral analytes reacted with the C−F bond in Q5 by a N-nucleophilic substitution reaction, leading to a linear correlation between the CD amplitude at the region of quinoline chromophores and the ee values of the chiral analytes, which can be used for the ee determination of chiral analytes. Furthermore, the CD intensity of Q5C-S containing a chiral motif at its C-terminus enhances via remote, favorable chiral communication when the chiral induction was triggered in situ by chiral analytes at the N-terminus matches the original helicity of Q5C-S , but decreases via remote, conflicted chiral communication when the chiral induction is triggered in situ by chiral molecules at the N-terminus mismatches the original one. The system can thus be used for determination of the absolute configuration of chiral analytes, given that the chirality of the chiral motif at the C-terminus of Q5C-S is known. 相似文献
10.
采用高效液相色谱法,在自制的纤维素-三(3,5-二甲基苯基氨基甲酸酯)(ATEO-OD)、纤维素-三(4-甲基苯基氨基甲酸酯)(ATEO-OG)和纤维素-三(4-甲基苯基甲酸酯)(ATEO-OJ)3种手性柱上对16种不同结构的手性化合物进行了拆分和比较.试验结果表明:16个手性样品在这3种手性固定相上分别获得了不同程度的拆分,A TEO-OD对所分析样品具有更好的手性识别能力,ATEO-OG和ATEO-OJ的手性识别能力相当. 相似文献
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12.
Yanqing Fan Jing He Lin Liu Guoqin Liu Shengzhu Guo Zhe Lian Xiaonan Li Weijie Guo Xuebo Chen Ying Wang Hua Jiang 《Angewandte Chemie (International ed. in English)》2023,62(28):e202304623
We report the synthesis and chiroptical properties of novel chiral carbon nanorings S p-/Rp-[12]PCPP containing a planar chiral [2.2]PCP unit, and demonstrate that S p-/Rp-[12]PCPP can not only host crown ether 18-Crown-6 to form ring-in-ring complexes with a binding constant 3.35×103 M−1, but also accommodate the complexes of 18-Crown-6 and S/R-protonated amines to form homochiral S @Sp -/ R @Rp - and heterochiral S @Rp -/ R @Sp - ternary complexes, displaying significantly larger binding constants of up to 3.31×105 M−1 depending on the chiral guests. Importantly, homochiral S @Sp -/ R @Rp - ternary complexes exhibit an enhanced CD signal, while the heterochiral S @Rp -/ R @Sp - ones have a constant CD signal compared with the chiral carbon nanorings, respectively, which suggests that homochiral S @Sp -/ R @Rp - ternary complexes display a highly narcissistic chiral self-recognition for S/R-protonated chiral amines, respectively. Finally, the chiral ternary complexes can be further applied to determine the ee values of chiral guests. The findings highlight a new application of carbon nanorings in supramolecular sensors, beyond the common recognition of π-conjugated molecules. 相似文献
13.
Dr. Shixin Fa Kouichi Egami Keisuke Adachi Dr. Kenichi Kato Prof. Tomoki Ogoshi 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(46):20533-20536
Chirality transfer is widely observed in life processes, and many artificial chiral transfer systems have been developed. In these systems, chiral information is transferred from chiral inducers to chiral acceptors by a direct chiral induction process and a direct chiral memorization process. We have developed ternary nondirect chiral transfer systems based on pillar[5]arenes, in which a third factor was introduced as a regulator. The planar chirality of an acceptor was induced and memorized by a chiral inducer with precise control by a regulator. In the chiral induction period, the feed sequence of the chiral inducer and regulator affected the chiral induction behavior of the chiral acceptor. The chiral memory ability of the acceptor was substantially improved by the combined action of the chiral inducer and regulator. 相似文献
14.
Triptycene‐Based Chiral Macrocyclic Hosts for Highly Enantioselective Recognition of Chiral Guests Containing a Trimethylamino Group
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Geng‐Wu Zhang Peng‐Fei Li Zheng Meng Han‐Xiao Wang Ying Han Prof. Chuan‐Feng Chen 《Angewandte Chemie (International ed. in English)》2016,55(17):5304-5308
A new class of chiral macrocyclic arene composed of three chiral 2,6‐dihydroxyltriptycene subunits bridged by methylene groups was designed and synthesized. Structural studies showed that the macrocyclic molecule adopts a hex‐nut‐like structure with a helical chiral cavity and highly fixed conformation. Efficient resolution was achieved through the introduction of chiral auxiliaries to give a couple of enantiopure macrocycles, which exhibited high enantioselectivity towards three pairs of chiral compounds containing a trimethylamino group. 相似文献
15.
手性有机酸保留指数的手性指数及原子类型电拓扑指数模型 总被引:8,自引:0,他引:8
基于手性碳原子的取代基次序规则,提出分子手性指数(wj),结合原子类型电拓扑指数(En)研究18种手性羟基酸和氨基酸的薄层色谱保留指数(RM)的定量关系(QSRR).经最佳变量子集回归建立最佳四元数学模型,传统的相关系数(R2)为0.969,留一法(LOO)的交互验证系数(Q2)为0.943,结果证明具有良好的稳健性及预测能力.根据进入该模型的4个结构参数(wj,E13,E16,E17)可知,影响手性有机酸保留指数的主要因素是分子的二维结构特征(如襒O,—OH,—NH2)和分子的手性特征.综上所述,新建wj及En对手性有机酸的保留指数表征具有合理性与有效性,为预测手性有机酸的保留指数提供一种有效方法. 相似文献
16.
Theoretical clues are desirable to help uncover the origin of bio‐homochirality in life, as well as the mechanisms for the asymmetric production of functional chiral substances. Here, an open‐to‐matter reaction network based on a model proposed by Plasson et al. is studied. In the extended model, the statistical fluctuations lead the system to break chiral symmetry autonomously, that is, without any initial enantiomeric excess or external influence. In the stability diagrams, we observe regions of parameter space that correspond to racemic, homochiral, chiral oscillatory, and, to our knowledge, for the first time in a chiral model, chaotic regimes. The dependencies of the final concentrations of chiral substances on the parameters are determined analytically and discussed for both the racemic and homochiral regimes. 相似文献
17.
Xiaopeng Feng Bowen Shen Bo Sun Jehan Kim Xin Liu Myongsoo Lee 《Angewandte Chemie (International ed. in English)》2020,59(28):11355-11359
Although considerable effort in recent years has been devoted to the development of two‐dimensional nanostructures, single‐layered chiral sheet structures with a lateral assembly of discrete clusters remain elusive. Here, we report single‐layered chiral 2D sheet structures with dual chiral void spaces in which discrete clusters of planar aromatic segments are arranged with in‐plane AB order in aqueous methanol solution. The chirality of the sheet is induced by the slipped‐cofacial stacks of rectangular plate‐like aromatic segments in the discrete clusters which are arranged laterally with up and down packing, resulting in dual chiral void spaces. The chiral nanosheets function as superfast enantiomer separation nanomaterials, which rapidly absorb a single enantiomer from a racemic mixture with greater than 99 % ee. 相似文献
18.
本文综述了近年来不对称Diels-Alder反应中手性催化剂研究的进展,对各类手性催化剂的性能和特点作了简要介绍. 相似文献
19.
Chirality is a unique phenomenon in nature. Chiral interactions play an important role in biological and physiological processes, which provides much inspiration for scientists to develop chiral materials. As a breakthrough from traditional materials, biointerface materials based on chiral polymers have attracted increasing interest over the past few years. Such materials elegantly combine the advantages of chiral surfaces and traditional polymers, and provide a novel solution not only for the investigation of chiral interaction mechanisms but also for the design of biomaterials with diverse applications, such as in tissue engineering and biocompatible materials, bioregulation, chiral separation and chiral sensors. Herein, we summarize recent advances in the study of chiral effects and applications of chiral polymer-based biointerface materials, and also present some challenges and perspectives. 相似文献
20.
Yuquan Guo Xiaoxiao Cheng Zixiang He Zhenyang Zhou Dr. Tengfei Miao Prof. Wei Zhang 《Angewandte Chemie (International ed. in English)》2023,62(52):e202312259
The construction of chiral superstructures through the self-assembly of non-chiral polymers usually relies on the interplay of multiple non-covalent bonds, which is significantly limited by the memory ability of induced chirality. Although the introduction of covalent crosslinking can undoubtedly enhance the stability of chiral superstructures, the concurrent strong constraining effect hinders the application of chirality-smart materials. To address this issue, we have made a first attempt at the reversible fixation of supramolecular chirality by introducing dynamic covalent crosslinking into the chiral self-assembly of side-chain polymers. After chiral induction, the reversible [2+2] cycloaddition reaction of the cinnamate group in the polymer chains can be further controlled by light to manipulate inter-chain crosslinking and decrosslinking. Based on this photo-programmable and dynamic chiral fixation strategy, a novel pattern-embedded storage mechanism of chiral polymeric materials was established for the first time. 相似文献