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Structural Study of Organic Compounds based on the First Principle

基于第一原理的有机化合物结构研究

基本信息

批准号：
10640522
负责人：
YOSHIDA Hiroshi
金额：
$ 2.11万
依托单位：
Hiroshima University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10640522/
关键词：
Density Functional Theory Ab initio MO Conformational Analysis Vibrational Analysis Polarizable Continuum Model 電子相関

项目摘要

Density Functional Study on 1,2-Dimethoxyethane in Aqueous Solution. Conformational behavior of 1,2-dimethoxyethane (DME) in aqueous solution has been attracted in the field of experimental and theoretical structural chemistry for a long time. The conformational stability of DME is known to be strongly affected by solvent environment. In the present study, we have observed the Raman spectra of DME in aqueous solution at various concentrations and have calculated the conformational energies by density functional theory (DFT) via Tomasi's polarizable continuum model (PCM) to understand the conformational stabilization mechanism of DME in aqueous solution. In the gas phase, the TTT conformer is the most stable and the TGG' conformer, as stabilized by an intramolecular 1,5-CH・・・O interaction, is the second. The PCM ealculations show that in aqueous solution the TGT conformer is the most stable and the TGG conformer is the second. The TGG conformer is greatly stabilized in aqueous solution … More because of the dipole moment of this conformer which is much larger than that of the other conformers. The theoretical results are in excellent agreement with the Raman spectroscopic observations. The present study has indicated that the dielectric property of aqueous environment strongly affects the conformational stabilization of DME.Density Functional Studies on Computational Accuracy in Normal Coordinate Analysis for Basic Molecules. Recently, density functional theory has rapidly developed and has shown that it calculates accurate chemical properties in a practical time. For the purpose of examining calculation accuracy in normal coordinate analysis using the density functional method, vibrational calculations were carried out using fundamental molecular observation wavenumbers which were reported in "Tables of Molecular Vibrational Frequencies" (T. Shimanouchi, 1972). The calculated wavenumbers by B3LYP using large basis sets are in good agreement with the observed wavenumbers at the accuracy of about 5%. As for the compounds involving halogens, calculated wavenumbers tend to deviate considerably to the lower wavenumber side. Less

水溶液中1，2-二甲氧基乙烷的密度泛函研究1，2-二甲氧基乙烷(DME)在水溶液中的构象行为长期以来一直受到实验和理论结构化学领域的关注。二甲醚的构象稳定性受溶剂环境的影响很大。在本研究中，我们观察了不同浓度的二甲醚在水溶液中的拉曼光谱，并用密度泛函理论(DFT)和Tomasi的极化连续介质模型(PCM)计算了构象能，以了解DME在水溶液中的构象稳定机理。在气相中，TTT构象最稳定，分子内1，5-CH···O作用稳定的TGG‘构象次之。PCM计算表明，在水溶液中，TGT构象最稳定，TGG构象次之。TGG构象在…水溶液中非常稳定这更多是因为这个构象的偶极矩比其他构象的偶极矩大得多。理论计算结果与拉曼光谱观测结果吻合较好。目前的研究表明，水环境的介电性质强烈影响二甲基甲醚的构象稳定性。碱性分子正坐标分析计算精度的密度泛函研究。近年来，密度泛函理论得到了迅速的发展，并显示出它能在实际时间内计算出准确的化学性质。为了检验用密度泛函方法进行简正坐标分析时的计算精度，用《分子振动频率表》(T.Shimanouchi，1972)中报道的基本分子观测波数进行了振动计算。用大基组B3LYP计算的波数与观测波数吻合较好，精度约为5%。对于含有卤素的化合物，计算的波数往往明显偏离较低的波数侧。较少