共查询到16条相似文献,搜索用时 62 毫秒
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采用密度泛函理论的B3LYP方法在6-311+G(d,p)基组上,对河豚毒素(TXX)进行了理论计算,得到了它的分子构型、热力学函数、偶极矩、脂水分配系数、红外光谱、核磁共振光谱、福井函数和前线轨道等信息,并对分子的IR谱和1HNMR谱进行了指认。模拟结果表明,TTX为一热力学非常稳定的弱极性且疏水性分子;福井函数和前线轨道计算表明,胍基N和H原子很可能是其发挥药理活性的亲电和亲核反应中心。 相似文献
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经不对称氨羟基化反应合成多西紫杉醇及其衍生物的新方法研究 总被引:5,自引:0,他引:5
首次用取代肉桂酸酯和叔丁氧基碳酰胺为原料,经改进的Sharphless不对称氨羟基化反应一步得到了多西紫杉醇及其衍生物的侧链,并最终得到了多西紫杉醇和新型抗癌化合物3,4-亚甲二氧基取代多西紫杉醇,该方法是目前合成多西紫杉醇及其衍生物的最简化和较高收率的路线。研究发现Sharphless不对称氨羟基化反应中手性配体、催化剂的用量和比例对原料的转化率、产物的产率等都有影响,当催化剂K2OsO2(OH)4、手性配体(DHQ)2PHAL的摩尔分数分别为原料的4%和5%时更倾向于生成多西紫杉醇衍生物侧链。所有新化合物及其结构均经过^1HNMR、^13CNMR、IR、MS、旋光度和元素分析等给予确证。3,4-OCH2O取代多西紫杉醇的初步药理活性显示具有较好的抗癌活性。 相似文献
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采用密度泛函理论的DFT/B3LYP/6-311+G(d,p)方法和基组,对甲基苯丙胺的UV-Vis光谱,IR光谱,1HNMR光谱和荧光光谱进行了理论模拟和指认。自然电荷计算表明,胺基N和H原子很可能是其发挥药理活性的亲电和亲核反应中心。 相似文献
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Since the discovery of a series of Au-based catalysts by Haruta et al. considerable progress has been made in understanding
the active role of Au in CO oxidation catalysis. This review provides a summary of recent theoretical work performed in this
field; in particular it addresses DFT studies of CO oxidation catalysis over free and supported gold nanoparticles. Several
properties of the Au particles have been found to contribute to their unique catalytic activity. Of these properties, the
low-coordination state of the Au atoms is arguably the most pertinent, although other properties of the Au cluster atoms,
such as electronic charge, cannot be ignored. The current consensuses regarding the mechanism for CO oxidation over Au-based
catalysts is also discussed. Finally, water-enhanced catalysis of CO oxidation on Au clusters is summarized. 相似文献
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为了从原子尺度上研究双金属的作用机理,采用基于密度泛函理论的第一性原理方法研究了甲烷在Ni-Pt和Ni-Pd双金属催化剂上的脱氢过程。计算结果表明,在Ni催化剂中引入Pt或Pd会大大减弱表面C原子的吸附,从而提高催化剂的抗积炭能力,而且甲烷第一步脱氢活化能会有所提高,反应活性略有降低。 相似文献
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The density functional theory, simplified by the local density approximation and mean-field approximation, is applied to study the surface properties of pure non-polar fluids. A reasonable long rang correction is adopted to avoid the truncation of the potential. The perturbation theory is applied to establish the equation for the phase equilibrium, in which the hard-core chain fluid is as the reference fluid and the Yukawa potential is used as the perturbation term. Three parameters, elk, d and ms, are regressed from the vapor-liquid equilibria, and the surface properties, including density profile, surface tension and local surface tension profile are predicted with these parameters. 相似文献