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首页> 外文学位 >A. Theoretical study of ion-headgroup interactions in dodecyl sulfate micelles. B. Fluorine hyperfine splittings in the ESR spectra of aromatic radicals. An experimental and theoretical investigation .
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A. Theoretical study of ion-headgroup interactions in dodecyl sulfate micelles. B. Fluorine hyperfine splittings in the ESR spectra of aromatic radicals. An experimental and theoretical investigation .

机译：A.十二烷基硫酸盐胶束中离子头基相互作用的理论研究。 B.芳香族基团的ESR光谱中的氟超细分裂。实验和理论研究。

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A. The presence of counterions in the headgroup region of ionic micelles is crucial for their existence. Although experiments can provide valuable insight into the nature of ion binding to micelles, they are not devoid of limitations and model assumptions. Also, theoretical study of ionic micelles has received relatively little attention compared to other polyelectrolytes. In this work we address this issue with a combination of molecular modeling tools using a well-known example, dodecyl sulfate. First, the Poisson-Boltzmann and Monte Carlo methods are employed to analyze the distribution of monovalent counterions in the vicinity of a static atomic model of dodecyl sulfate micelle in a dielectric continuum. The latter approach is also applied to the practically important case of micellar catalysis and provides a simpler and more consistent kinetic description than other methods. The next level of sophistication are molecular dynamics simulations of micelle solutions where the solvent is modeled explicitly. It is found that simple monovalent ions favor direct coordination to headgroup(s) and this tendency is much more pronounced compared to a methyl sulfate solution. Structural information on ion-headgroup contact pairs obtained from classical molecular dynamics simulations is found to correlate with the results of quantum mechanical calculations on small clusters.; B. Fluorine hyperfine coupling constants (hfccs) in aromatic radicals are of significance in the elucidation of their electronic structure. However, experimental ESR data on fluorinated anion and polyacene radicals in general are lacking in the literature and to date there has not been a systematic study of fluorine hfccs in molecules of this size using modern methods of electronic structure calculation. This work reports ESR spectra and hfccs of anion radicals of 1,2,3,4-tetrafluoronaphthalene, 1,2,3,4-tetrafluoroanthracene, and 9,10-perfluoroanthraquinone. For these and other fluorinated aromatic ion-radicals density functional (B3LYP) calculations of F-hfccs with the EPR-III basis set give the best agreement with experiment (15%). It is also possible to correlate the experimental fluorine hfccs with the calculated π-electron spin populations in the C-F fragment, thus supporting the generally accepted view of the separation of σ- and π-electrons in aromatic molecules.
机译： A 。离子胶束的头基区域中抗衡离子的存在对于它们的存在至关重要。尽管实验可以提供有关离子束与胶束结合的性质的宝贵见解，但它们并非没有局限性和模型假设。而且，与其他聚电解质相比，离子胶束的理论研究受到的关注相对较少。在这项工作中，我们使用著名的例子十二烷基硫酸盐结合分子建模工具来解决这个问题。首先，采用Poisson-Boltzmann方法和Monte Carlo方法分析介电连续体中十二烷基硫酸盐胶束的静态原子模型附近的单价抗衡离子的分布。后一种方法也适用于胶束催化的实际重要案例，并且比其他方法提供了更简单，更一致的动力学描述。复杂性的下一个层次是胶束溶液的分子动力学模拟，其中对溶剂进行了显式建模。发现简单的一价离子有利于直接与头基配位，并且与硫酸甲酯溶液相比，这种趋势更为明显。从经典分子动力学模拟获得的离子头基接触对的结构信息被发现与小团簇的量子力学计算结果相关。 B 。芳香族基团中的氟超精细偶合常数（hfccs）在阐明其电子结构方面具有重要意义。然而，文献中通常缺乏关于氟化阴离子和多并苯自由基的实验ESR数据，并且迄今为止，还没有使用现代电子结构计算方法对这种大小的分子中的氟hfcc进行系统的研究。这项工作报告了1,2,3,4-四氟萘，1,2,3,4-四氟蒽和9,10-全氟蒽醌的阴离子自由基的ESR谱和hfcc。对于这些以及其他带有EPR-III基集的F-hfccs的氟化芳族离子自由基密度泛函（B3LYP）计算，与实验（15％）具有最佳一致性。还可以将实验氟hfcc与C-F片段中计算出的π电子自旋种群相关联，从而支持芳香族分子中σ和π电子分离的公认观点。

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