SUBSTITUENT AND SOLVATION EFFECTS ON GAS-PHASE ACIDITIES
SUBSTITUENT AND SOLVATION EFFECTS ON GAS-PHASE ACIDITIES
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DOI：
10.1021/ja00514a031
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发表时间：
1979-01-01
影响因子：
15
通讯作者：
MCIVER, RT
中科院分区：
文献类型：
--
作者：
BARTMESS, JE;SCOTT, JA;MCIVER, RT
多种溴系酸的结构与其固有的气相酸度有关。极性是气相中所有取代基对阴离子中心的影响的一个主要因素，通常逆转了由给电子和吸电子基团的溶液反应性所分配的“极性”效应。甲基通过极性、极化性和超共轭相互作用与阴离子中心相互作用。偶极非质子溶剂的溶剂化导致相对酸的压缩很小，但水作为溶剂将许多取代基效应压缩到其内在值的四分之一。阐明结构与反应活性之间的关系一直是物理有机化学的主要目标。尽管现代结构概念为分析取代基和反应位点之间的分子内相互作用提供了一个很好的框架，但并没有给出，因此，溶剂化在这一努力中的作用一直是不确定的
The structure of a wide variety of Br^ nsted acids is related to their intrinsic gas-phase acidity. Polarizability is a major factor in the gas phase in the effect of all substituents on anionic centers, often reversing the “polar” effect assigned from solution phase reactivities of both electron-donating and electron-withdrawing groups. Methyl groups interact with anionic centers by a mixture of polar, polarizability, and hyperconjugative interactions. Solvation by dipolar aprotic solvents results in little compression of relative acidities, but water as solvent compresses many substituent effects to one-quarter oftheir in-trinsic value.Elucidation of the relationship between structure and re-activity has long been a chief goal of physical organic chem-istry. The role of solvation in this endeavor has been an un-certain one, since modern structural concepts, though they provide a good framework for analysis of intramolecular interactions between substituent and reactive site, donot give