排序方式: 共有73条查询结果,搜索用时 15 毫秒
41.
以均苯四甲酸二酰亚胺和1,5-萘二酚为基本结构单元,设计合成了一种不对称的37-冠-10 (1), 解析了其晶体结构,进而采用紫外和核磁等手段研究了其与一些阳离子的键合行为. 结果表明,冠醚1存在分子内的电荷转移相互作用,导致的较小空腔对锂离子表现出较强的键合能力. 相似文献
42.
A supramolecular porous nanosphere is constructed from amphiphilic cholic acid-modified cyclodextrin triggered by guest sodium 1-naphthylamino-4-sulfonate and is comprehensively characterized by nuclear magnetic resonance (NMR), light scattering, transmission electron microscopy, and gas adsorption experiments. The results obtained show that the porous nanosphere with the radius of 25-35 nm has moderate nitrogen adsorption ability. Further NMR, circular dichroism, and the fluorimetric titrations on the self-assembling behavior in aqueous solution reveal that the substituting group of the guest molecule and pH values are the key to induce the formation of the porous nanosphere. 相似文献
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二氧化碳作为温室气体中最重要的组成部分,其含量的变化将直接影响全球气候变化,在燃烧后气体中选择性捕获CO2,对减缓因CO2浓度过高引发的环境问题具有十分重要的意义.本文采用第一性原理计算的方法,研究了V2CO2 MXene材料对CO2的选择性吸附性能.首先研究了不同官能团V2CTX MXene材料的结构和性质,发现V2CO2具有良好的稳定性.后研究了V2CO2对CO2的吸附行为,结果表明,当CO2被水平吸附时,V2CO2对CO2气体分子的吸附能力较强且均满足在高性能吸附剂表面吸附CO2的理想值(-0.42 eV-0.82 eV),可以适用于探测/捕获CO2气体分子.此外,进一步研究了相同条件下V<... 相似文献
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Sun JX Zhao XY Fu XF Yu HY Li X Li SM Ruan HL 《Chemical & pharmaceutical bulletin》2012,60(6):785-789
Phytochemical investigations of the root bark of Juglans cathayensis DODE. led to the isolation of three new naphthalenyl glycosides, Jugnaphthalenoside A-C (1-3). Their structures were elucidated on the basis of extensive analysis of spectroscopic data. The cytotoxicities of the three new compounds were also evaluated. 相似文献
46.
Zhang ZJ Zhang HY Wang H Liu Y 《Angewandte Chemie (International ed. in English)》2011,50(46):10834-10838
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An acceptor-donor-acceptor-type linear molecule 1(2+) containing one electron-rich naphthoxy (NP) unit and two monocharged viologen (MCV) units was synthesized. Through the noncovalent interaction of cucurbit[8]uril (CB[8]) with one NP and one MCV in 1(2+), we first obtained a [2]pseudorotaxane ([1(2+)]?CB[8]), and the excess CB[8] included simultaneously the two bare MCV units of two [2]pseudorotaxanes to form a [5]pseudorotaxane ([1(2+)](2)?[CB[8]](3)). Its transformation to [3]pseudorotaxane was achieved through detaching the two axle molecules in the presence of acid, and then the addition of base may result in a reversible switch between two different pseudorotaxanes. This novel methodology elongating reversibly linear molecules by noncovalent interactions will benefit the development of stimuli-responsive functional molecular devices. 相似文献
48.
A[3]rotaxane 1 involving two naphtho-21-crown-7(N21C7) rings and a dumbbell-shaped component 4 was synthesized.The dumbbell-shape molecule 4 contains one viologen nucleus,two secondary alky] ammonium sites and two phenyl stoppers.After threading the N21C7 ring with the thread-like ammonium guest 3,the copper(1)-catalyzed Huisgen alkyne-azide 1,3-dipolar cycloaddition(CuAAC "click" reaction),was performed to connect the pseudorotaxanes with viologen unit 2 and generate 1. Through treating the[3]rotaxane by the base and acid circularly,the two N21C7 rings can make shuttling motion along the axle.Meanwhile the distance between the electron-deficient viologen unit and the electron-rich naphthol group can be adjusted precisely along with a remarkable intramolecular charge-transfer (CT) behavior. 相似文献
49.
In continuation of our interest in the synthesis of glycosidase inhibitors, we report herein an efficient synthesis of three new polyhydroxylated amino cyclohexane derivatives (aminocyclitols) that may potentially possess important biological activities. The key step involved the highly stereoselective dihydroxylation of protected azido cyclohexene derivatives 5, 9, and 15, which were easily red from D-(-)-quinic acid. The subsequent hydrogenation step was conducted under acidic conditions to provide the target molecules in an efficient manner with high overall yields. 相似文献
50.
Two beta-cyclodextrin (beta-CD) derivatives bearing steroid groups (1 and 2) were synthesized by the condensation of mono(6-aminoethylamino-6-deoxy)-beta-CD with cholic acid and deoxycholic acid, respectively, and their original conformations and binding behavior to the organic anion of naphthalenesulfonate derivatives were investigated by using 1H NMR spectroscopy and spectrofluorometric titration in combination with computational methods. The 2D NMR experiments reveal that the steroid groups attached to the beta-CD rim could be deeply embedded in the beta-CD cavity to form the intramolecular (for 1) or intermolecular (for 2) inclusion complexes in aqueous solution. Upon complexation with naphthalenesulfonate derivatives, modified beta-CDs display two obviously different binding modes, that is, the competitive inclusion mode and the induced-fit inclusion mode, which is consistent with the results of molecular modeling study. The two modes and the strict size/shape fitting relationship between the hosts and guests reasonably explain the different binding behaviors and molecular selectivity of host beta-CDs 1 and 2 toward the naphthalenesulfonate guests. Therefore, the cholic acid- or deoxycholic acid-modified beta-CDs could effectively recognize the size/shape of guest molecules as compared with the parent beta-CD, giving good molecular selectivity up to 24.9 for the disodium 2,6-naphthalenedisulfonate/disodium 1,5-naphthalenedisulfonate pair by the host 1. 相似文献