Concepts of sterically hindered resonance and buttressing effect: gas-phase acidities of methyl-substituted benzoic acids and basicities of their methyl esters
作者:Michele Decouzon、Peter Ertl、Otto Exner、Jean Francois Gal、Pierre Charles Maria
DOI:10.1021/ja00078a052
日期:1993.12
Two classical terms «Steric Hindrance to Resonance» and «Buttressing Effect» are revisited on the basis of the gas-phase acidities of nine methyl-substituted benzoic acids and of the gas-phase basicities of their methyl esters, measured using FT-ICR spectrometry. By combining these data with published heats of formation of the neutrals and by using the principle of isodesmic reactions, relative enthalpies
根据使用 FT-ICR 光谱法测量的九种甲基取代苯甲酸的气相酸度及其甲酯的气相碱度,重新审视了两个经典术语“共振位阻”和“支撑效应” . 通过将这些数据与已公布的中性形成热相结合,并利用等分反应原理,分别评估酸分子、它们的阴离子(去质子化)和质子化阳离子(被质子化形式取代)的相对形成焓。相应的甲酯)。所有物种的能量也在半经验水平 (AM1) 计算