Theoretical Analysis on substituent effects for Chemical Reactions by using Ab Initio Molecular Orbital Calculations.

使用从头算分子轨道计算理论分析化学反应中取代基的影响。

• 批准号: 09640640
• 负责人: HORI Kenzi
• 金额: $ 1.66万
• 依托单位: YAMAGUCHI UNIVERSITY
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1997
• 资助国家: 日本
• 起止时间: 1997 至 1998
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640640/
• 关键词: Ab initio MO calculations; Substituent effect; Proton Affinity; Yukawa-Tsuno equation; プロトンアフィュティ; 機構変動; プロトンアフィニティ

It was observed that there is a linear relationship between the activation free energies of the Menshutkin reaction (Eq.1) and the proton affinities (deltaPA) relative to the ammonia for corresponding bases with a nitrogen donor. The Ea's are dependent on the hybridization of the nitrogen, i.e., the sp^2 donors make a straight line which is different from that for the sp3 donors.CH_3 I + B * CH_3 B^++GAMMA B (Base with a nitrogen atom) (1)Although N,N-dimethylaniline has an sp^3 nitrogen, its deltaPA deviates from the sp^3 line. The 4-substituted derivatives of the base are not on the line, either. In the present study, ab initio molecular orbital calculations were used to explain why there are the linear relationship between the two energies. It was ascertained that the calculated activation energies (Ea) show a linear relationship with deltaPA.The Ea's also have a similar relationship with the calculated protonation energies.We also compared experimental results of Professor Tsuno's group with the calculated results concerning with the S_n I - S_n2 mechanism transition. It was ascertained that the reaction center is stabilized by the substituents of reactants and nucleophiles. This is the origin of the mechanism transition.In the present study, we investigated how substituents change reactivity and physico-chemical properties of molecules. These results include important informations for experimental chemists and useful for designing new molecules. It becomes, therefore, clear that theoretical chemists have to work together with experimental chemists in order to develop chemistry further.

我们观察到，对于有氮供体的相应碱，Menshutkin反应的激活自由能（Eq.1）与相对于氨的质子亲和（deltaPA）之间存在线性关系。Ea依赖于氮的杂化，也就是说，sp^2给体与sp^ 3给体是一条不同的直线。CH_3 I + B * CH_3 B^++GAMMA B（带氮原子的碱）(1)N，N-二甲基苯胺虽然有sp^3氮，但其δ pa偏离sp^3线。底的4代导数也不在直线上。在本研究中，采用从头算分子轨道计算来解释两种能量之间存在线性关系的原因。计算得到的活化能（Ea）与δ pa呈线性关系。电子能谱与计算出的质子化能也有类似的关系。我们还将Tsuno教授组的实验结果与s_i - S_n2机制跃迁的计算结果进行了比较。确定了反应中心是由取代基和亲核试剂稳定的。这就是机制转变的起源。在本研究中，我们研究了取代基如何改变分子的反应性和物理化学性质。这些结果为实验化学家提供了重要信息，对设计新分子也很有用。因此，很明显，为了进一步发展化学，理论化学家必须与实验化学家一起工作。

项目成果

K.Hori: "Theoretical Study on Decomposition of gamma-halo Allylalkoxide and beta-halo Acrylate ions." Theor.Chem.Account.(in press). (1999)

K.Hori：“γ-卤代烯丙醇盐和 β-卤代丙烯酸根离子分解的理论研究”。

Hori,Kenji: "Theoretical study Alkaline Hydrolysis of Amides in the Gas phase" Tetrahedron. 53. 4317-4330 (1997)

Hori，Kenji：“酰胺在气相中碱性水解的理论研究”四面体。

Hori, Kenji: "Abinitio Molecular Orbital Study on the Mechanism of Amide hydrolysis Dependent on Leaving Groups." Tetrakedron. 53. 4317-4330 (1997)

Hori, Kenji：“依赖于离去基团的酰胺水解机制的从头开始分子轨道研究”。

Hori, Kenji: "Thearetical study on Decomposition of αーhalo allylalkoxide and β-halo Acrylateios" Thearetical Chemistry Secount. (発行予定). (1999)

Hori, Kenji：“α-卤代烯丙基醇盐和 β-卤代丙烯酸酯的分解的理论研究”理论化学 Secount（即将出版）。

Hori,Kenzi: "Strategy for Designing New Le^+ ion specific Receptors.A Combination of Theoreticul Calculations and Experimental Technique" J.Incl Pherom Mol.Regog. 32. 311-329 (1998)

Hori，Kenzi：“设计新Le^离子特异性受体的策略。理论计算和实验技术的结合”J.Incl Pherom Mol.Regog。