Hatanaka Masashi
School of Engineering, Tokyo Denki University , 5 Senju-Asahi-cho, Adachi-ku, Tokyo 120-8551, Japan.
J Phys Chem A. 2015 Feb 12;119(6):1074-86. doi: 10.1021/acs.jpca.5b00133. Epub 2015 Feb 3.
Protomeric tautomerism is analyzed in view of the topological charge stabilization rules. Based on Hückel molecular orbital considerations and modern DFT calculations, it was found that the branching of amino or hydroxyl groups significantly contributes to the stability of major species through the first- and second-order perturbations with respect to the isoelectronic hydrocarbon. While amino-imino tautomerism is almost completely dominated by topological charge stabilization, hydroxyl-oxo tautomerism is affected by changes in the resonance integral of C-O/C═O bonds. Nevertheless, apart from side effects such as hydrogen bonds or solvent effects, a quantitative preference rule for the prediction of the tautomeric stability can be developed using topological π-electron energetics. As well as the analyses of simple bases, applications to complex or extended systems are exemplified analyzing purine bases, polyguanide, and polyuret. The present approach can be useful in conjunction with chemical intuition that comes from conventional valence bond theory.
基于拓扑电荷稳定规则分析了原聚体互变异构现象。基于休克尔分子轨道理论和现代密度泛函理论计算发现，氨基或羟基的分支通过相对于等电子烃的一阶和二阶微扰对主要物种的稳定性有显著贡献。虽然氨基-亚氨基互变异构几乎完全由拓扑电荷稳定主导，但羟基-氧代互变异构受C-O/C═O键共振积分变化的影响。然而，除了氢键或溶剂效应等副作用外，利用拓扑π电子能量学可以建立预测互变异构稳定性的定量偏好规则。除了对简单碱的分析外，还通过对嘌呤碱、聚胍和聚脲的分析举例说明了该方法在复杂或扩展体系中的应用。本方法与来自传统价键理论的化学直觉相结合可能会很有用。
