计算化学辅助有机化学教学——以二嗪异构体的碱性和稳定性比较为例  

Computational Chemistry Aided Organic Chemistry Teaching:A Case of Comparison of Basicity and Stability of Diazine Isomers

作　　者：吕仁庆[1] 王淑涛[1] 王芳[1] 沈国平[1] Renqing Lü;Shutao Wang;Fang Wang;Guoping Shen(College of Chemistry and Chemical Engineering,China University of Petroleum(East China),Qingdao 266580,Shandong Province,China)

机构地区：[1]中国石油大学(华东)化学化工学院,山东青岛266580

出　　处：《大学化学》2025年第3期76-82,共7页University Chemistry

摘　　要：本文采用计算量子化学方法在B3LYP/6-311+g(d,p)水平上比较了气态二嗪三种异构体的碱性强度和稳定性。计算结果表明,三种异构体的碱性强度顺序为哒嗪>嘧啶>吡嗪。同时,通过优化结构单点能的计算,判断三种异构体的稳定性顺序为嘧啶>吡嗪>哒嗪,且其共轭酸的稳定性顺序亦呈现相似趋势,即嘧啶-H>吡嗪-H>哒嗪-H。此外,本文采用前线轨道理论定性解释了哒嗪明显异于嘧啶和吡嗪的特殊热力学性质(燃烧热和标准生成焓)。将计算化学引入到有机物酸碱性和稳定性的教学中,有助于学生深入理解Lewis酸碱性、等键反应、最高已占据分子轨道(HOMO),最低未占据分子轨道(LUMO)、前线轨道能隙值等核心概念和杂化轨道理论,教学效果显著提高,成为提升有机化学教学质量的有效辅助工具。The basicity strength and stability order of three isomers of diazine in the gas phase were compared by using computational quantum chemistry methods at the B3LYP/6-311+g(d,p)level.The calculation results indicate that the order of basicity strength is pyridazine>pyrimidine>pyrazine.Based on single point energy calculations of optimized structures,the stability order of the isomers is pyrimidine>pyrazine>pyridazine.Similarly,the stability of their conjugated acids follows the same trend:pyrimidine-H>pyrazine-H>pyridazine-H.The distinct thermodynamic properties of pyridazine,such as its combustion heat and standard enthalpy of formation,were qualitatively explained using frontier orbital theory.Incorporating computational chemistry into the teaching of organic acid-base properties and stability helps students deeply understand key concepts,such as Lewis acid-base properties,isodesmic reactions,highest occupied molecular orbitals(HOMO),lowest unoccupied molecular orbitals(LUMO),frontier orbital gaps,and hybrid orbital theory.This approach significantly enhances teaching effectiveness and serves as a valuable tool for improving the quality of organic chemistry education.

关 键 词：二嗪 气相碱性 等键反应 计算化学 杂化类型 

分 类 号：G64[文化科学—高等教育学] O6[文化科学—教育学]