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1.
用差紫外光谱滴定法考察了新型猪去氧胆酸分子钳1~6对苯胺、对甲氧基苯胺、对硝基苯胺等中性分子的识别性能,测定了主客体间的结合常数(Ka)和自由能变化(△G°)。结果表明,分子钳主体对所考察的客体分子显示良好的识别作用,主客体间形成1∶1型超分子配合物,最大结合常数可达3123.46L.mol-1,识别作用的主要推动力为氢键,范德华力等的协同作用。讨论了主体与客体的识别模式以及客体间形状、大小匹配和几何互补等因素对形成超分子配合物的影响,并利用核磁共振氢谱与计算分子模拟作为辅助手段对实验结果与现象进行了解释。  相似文献   

2.
手性芳酰胺类分子钳对氨基酸衍生物的对映选择性识别   总被引:1,自引:0,他引:1  
在微波辐射条件下,以联苯二甲酸为间隔基,L-氨基酸甲酯为手臂,合成了3个新型芳酰胺手性分子钳。这些化合物的结构经1HNMR,IR,MS和元素分析确证。利用差紫外光谱滴定法考察了其与D/L氨基酸甲酯的对映选择性识别性能。结果表明,分子钳2a~2c对所考察的氨基酸甲酯均具有识别能力,其对D-氨基酸甲酯的识别优于对L-氨基酸甲酯的识别。从主客体间的大小形状匹配及几何互补关系等方面对这些受体的识别能力及对映选择性进行了讨论。  相似文献   

3.
以脱氧胆酸为spacer,通过三光气桥连各种芳胺,合成了新的氨基甲酸酯型分子钳受体1~4,这些化合物的结构经IR,^1HNMR和元素分析所证实。利用差光谱滴定法考察了其与D/L氨基酸甲酯的对映选择性识别性能。结果表明,分子钳1~4对所考察的氨基酸甲酯均具有识别能力,其对D-氨基酸甲酯的识别优于对L-氨基酸甲酯的识别。从主客体间的大小形状匹配及几何互补关系等方面对这些受体的识别能力及对映选择性进行了讨论。  相似文献   

4.
新型鹅去氧胆酸分子钳的设计合成和分子识别性质研究   总被引:2,自引:0,他引:2  
以鹅去氧胆酸为隔离基, 芳香族化合物为手臂设计合成了一类新型的分子钳, 其结构经1H NMR, IR, MS及元素分析确证. 利用紫外光谱滴定法考察了其与D/L氨基酸甲酯的对映选择性识别性能. 结果表明, 分子钳3a3e对所考察的氨基酸甲酯均具有识别能力, 其对L-氨基酸甲酯的识别优于对D-氨基酸甲酯的识别. 从主客体的大小形状匹配及几何互补关系等方面对这些受体的识别能力及对映选择性进行了讨论.  相似文献   

5.
芳酰胺分子钳对阴离子的识别研究   总被引:2,自引:0,他引:2  
利用差紫外光谱法考察了新的分子钳1~4对阴离子的识别性能,测定了25 ℃下,在CHCl3中主客体间的结合常数(Ka)和自由能变化(ΔG°). 结果表明,所有分子钳主体对所考察的客体分子显示良好的识别作用,主客体间形成1∶ 1型超分子配合物.识别作用的主要推动力为多重氢键作用.并利用核磁共振氢谱与计算机模拟作为辅助手段对实验结果进行了解释.  相似文献   

6.
氨基甲酸酯型脱氧胆酸分子钳对中性分子的识别性能研究   总被引:3,自引:0,他引:3  
利用差紫外光谱法考察了新型分子钳16对苯胺、对硝基苯胺、对甲氧基苯胺等中性分子的识别性能, 测定了25 ℃下, 在CHCl3中主客体间的结合常数(Ka)和自由能变化(ΔG0). 结果表明, 所有分子钳主体对所考察的客体分子显示良好的识别作用, 主客体间形成1∶1型主客体络合物. 识别作用的主要推动力为多重氢键和π-π重叠等的作用. 讨论了主客体间形状、大小匹配和几何互补及识别模式等因素对识别能力的影响, 并利用核磁共振氢谱与计算机模拟作为辅助手段对实验结果进行了解释.  相似文献   

7.
王健 《应用化学》2009,26(5):501-506
摘要 以α-猪去氧胆酸为隔离基,在3位桥联不同的D,L-氨基酸甲酯作手性臂,合成了具有不同手性中心和裂穴的新型分子钳受体。结构均经1H NMR、IR及元素分析确证,并考察了其对D/L-氨基酸甲酯的识别性能。初步研究表明,这类分子钳对D/L-氨基酸甲酯具有良好的识别性能,其结合常数(Ka)可达5.24 × 103 L•mol-1。  相似文献   

8.
赵志刚  刘兴利  李晖  唐晓丽 《有机化学》2008,28(7):1233-1237
以刚性的脱氧胆酸甲酯为隔离基, 在其3位连接苯甲酰基, 12位连接手性不对称脲, 设计合成了一类新型的手性分子钳. 其结构均经1H NMR, IR, MS和元素分析确证, 并且考察了其对中性分子和D/L-氨基酸甲酯的识别性能. 实验结果表明, 这类分子钳人工受体不仅对中性有机小分子具有良好的识别能力, 而且对D/L-氨基酸甲酯亦具有优良的对映选择性识别性能.  相似文献   

9.
胆甾类分子钳对氨基酸衍生物的对映选择性识别   总被引:8,自引:0,他引:8  
用差紫外光谱滴定法考察了以脱氧胆酸作spacer的手性分子钳1~3对一系列α-氨基酸甲酯的对映选择性识别性能。结果表明,分子钳1和2与客体氨基酸甲酯形成1:1型超分子配合物,并显示较好的手性识别能力。分钳3对所考察的氨基酸甲酯均没有明显的识别作用。讨论了主-客体间尺寸/形状匹配、几何互补等因素对形成超分子配合物的影响,并利用计算机模拟作辅助手段对实验结果和现象进行了解释。  相似文献   

10.
α-猪去氧胆酸类分子钳的设计合成   总被引:9,自引:2,他引:7  
以α-猪去氧胆酸为隔离基,芳香族化合物为手臂设计合成了一类新型的酯键 型分子钳,结构均经^1H NMR,IR,MS及元素分析所确证,并且考察了其对芳香胺类 化合物和D/L-氨基酸甲酯的识别性能.初步研究结果表明,这类分子钳受体不但 对中性小分子具有识别性能,而且对D/L-氨基酸甲酯具有对映选择性识别性能.  相似文献   

11.
本文应用分子模拟途径研究了系列反应物丙烯基羟基乙烯酮二硫代乙缩醛在有、无分子筛催化条件下Thio-Claisen重排。我们证实Sreekumar等人实验在有、无分子筛催化条件下的Thio-Claisen重排结果可分别通过分子筛-分应物之间相互作用的能学和反应物的空间能计算得到合理解释。本文的方法能成功地识别一个给定Thio-Claisen重排在有、无分子筛催化条件下的优化产物。  相似文献   

12.
尹屹梅  林祥钦 《化学进展》2001,13(5):337-342
研制分子计算机也许是突破传统半导体电子计算机发展极限的唯一出路。本文简述了最近十年分子计算机的研究进展, 重点讨论了DNA 计算机和生物分子计算机的研究成果, 并对可能为人类提供思考和尝试范本的生物活细胞中蛋白质的各种计算机制的研究给予了充分的关注。引用了43篇文献。  相似文献   

13.
The search for the lowest energy conformation of complex {β-cyclodextrin (β-CD)+chlorambucil} were carried out by molecular mechanics method. Theoretical calculations of molecular interactions of complex were carried out using the molecular orbital method. The correlation between energy changes and molecular structures are discussed. The large interaction energies calculated by the molecular orbital method bears out the inclusion phenomenon.  相似文献   

14.
1 INTRODUCTION Zeolites have attracted much attention in both scientific and industrial areas for their special characteristics and multiple uses. Zeolites are composed of TO4 (T = Si, Al, Ga, P, etc.) tetrahedra which are connected with each other by sharing oxygen atoms to produce a complex and repetitive three-dimensional atom network with regular molecular dimension cavities joined by channels. Shape selectivity is the most important property of zeolites. Combined with the possib…  相似文献   

15.
Hydrogen-bonded cluster analysis of liquid D-methanol data at room and elevated temperatures was carried out and nature of molecular association was extracted. The analysis, based on a choice of suitable centre structure corresponding to an effective pair potential, hardsphere plus a square-well ledge, determines if the H-bonded clusters are broken with the rise in temperature. It is shown that clusters present at room temperature are more or less preserved at elevated temperatures. At low Q (Q being the scattering vector), Ornstein–Zernike behaviour is produced extremely well. The analysis enables the extraction of atom–atom distribution functions, such as g OO(r), g OD(r) and g DD(r), the variation of which with temperature confirm the same observation.  相似文献   

16.
银纳米粒子表面油酸盐吸附的分子模拟   总被引:3,自引:0,他引:3  
采用分子力学方法模拟了油酸盐分子在银纳米粒子(111)表面的两种主要吸附形态: 双键吸附和羧基吸附, 计算了不同溶剂环境中油酸盐分子的吸附能和振动频率. 结果表明: 作为银纳米粒子保护剂的油酸盐能够稳定地存在于极性和非极性溶剂环境中, 与银表面的作用方式随溶剂极性的改变而改变, 水相中以双键吸附为主, 而在有机相中主要是羧基吸附. 这与红外光谱实验的推论基本吻合. 从而在分子水平上为实验结果提供了有价值的理论支持和微观信息.  相似文献   

17.
This work was focused on the influence of match degree of structure parameters i.e. molecular size, volume and polarity (denoted as Rd, Vd and Pd) between imprinted cavities in Qu-MIP and Xn on the adsorption selectivity. The results presented that the influence of Rd on the adsorption selectivity was the largest and the most regular, while the influence of Pd was the smallest and the most irregular. Besides, the influence degree of Vd was decreased in general with the increase of Rd. However, as Rd was in the threshold of [0.99, 1.02], Vd would rise to the major influence factor. Furthermore, utilizing data obtained from experiment, the influence authority of Rd, Vd and Pd on the adsorption selectivity was calculated theoretically through multiple linear regression and principal component analysis of IBM SPSS Statistics 20, and results showed the authority order was Rd, Vd and Pd at any circumstance despite the value was different, which was in accordance with the result we directly inducted from the experiment.  相似文献   

18.
This paper presents a computational study on the formation of a molecular necklace formed by specific threading of cyclodextrins (CDs) on block copolymers. Structural as well as energetic principles for the selective complexation of - and -cyclodextrin with poly(ethylene oxide)–poly(propylene oxide) block copolymers (PEO–PPO) are elucidated considering a diblock copolymer of equimolecular composition (PEO)4–(PPO)4 as guest. A non-statistical distribution of CDs, i.e. -CDs primarily located on the PEO chain and -CDs on PPO blocks of the polymer, is based on a variety of structural features and energetic preferences considering both potential as well as solvation energies. This selectivity becomes already obvious considering 1:1 complexes between PEO and PPO monomers and the two CDs, but is increasingly evident when calculating higher order ensembles. Besides the host–guest interaction, docking between CDs themselves is an important, also non-statistical, prerequisite for the self-assembly of highly ordered tubes. The formation of intermolecular hydrogen bonds between adjacent CDs in a tubular aggregate gives an important contribution to the overall stability of the molecular necklace. The net effect, based on the preferential interaction between host and guest as well as between the host molecules themselves, results in the formation of a stable, highly ordered macromolecular, multicomponent aggregate.  相似文献   

19.
We have performed classical molecular dynamics simulations and quantum‐chemical calculations on molecular crystals of anthracene and perfluoropentacene. Our goal is to characterize the amplitudes of the room‐temperature molecular displacements and the corresponding thermal fluctuations in electronic transfer integrals, which constitute a key parameter for charge transport in organic semiconductors. Our calculations show that the thermal fluctuations lead to Gaussian‐like distributions of the transfer integrals centered around the values obtained for the equilibrium crystal geometry. The calculated distributions have been plugged into Monte‐Carlo simulations of hopping transport, which show that lattice vibrations impact charge transport properties to various degrees depending on the actual crystal structure.  相似文献   

20.
分子识别是生物体系的基本特征,并在生命活动中起中心作用。生物酶高效专一地催化生化反应,抗体与抗原的结合,蛋白质分子与DNA序列的相互作用等都源于精确的分子识别[1,2]。利用合成的人工受体与适当底物之间的分子识别以建立仿生仿酶模型的研究,已成为生物有机化学前沿富有挑战性的领域。分子裂缝作为一类新型的人工受体,以其灵活的结构以及易于将功能团聚集在受体与底物结合的活性部位上等优点,引起了人们的广泛关注[3-5]。胆甾因其具有刚性的凹面结构和天然的手性,是构筑分子裂缝人工受体的理想结构单元。我们曾报道3α-OH和7α-OH同…  相似文献   

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