Acidities of strong neutral Bronsted acids in different media

作者：Raamat Elin; Kaupmees Karl; Ovsjannikov Gea; Trummal Aleksander; Kuett Agnes; Saame Jaan; Koppel Ivar; Kaljurand Ivari; Lipping Lauri; Rodima Toomas; Pihl Viljar; Koppel Ilmar A; Leito Ivo^*

来源：Journal of Physical Organic Chemistry, 2013, 26(2): 162-170.

DOI：10.1002/poc.2946

• acidity
• solvent effects
• solvation
• superacids
• pKa

Acidities of different families of acids are examined in media of different physical and chemical nature: water, acetonitrile (AN), 1,2-dichloroethane (DCE) and the gas phase, with special emphasis on strong acids. Included are OH (carboxylic acids, alcohols, and phenols), NH (sulfonamides, imides), and CH (phenylmalononitriles, etc.) acids as well as HCl, HBr, and HI. Dependence of the acidity trends on moving from water to the gas phase on the nature of the acidity center, and the molecular structure are analyzed. The acidity orders are different in water, AN, DCE, and the gas phase. In some cases the differences are dramatic. AN and DCE display similar acidity order in the set of the investigated acids. It is demonstrated that the decisive factor for the behavior of the acids when transferring between different media is the extent of charge delocalization in the anion and that the recently introduced weighted average positive sigma parameter in spite of its simplicity enables interpretation of the trends in the majority of cases.

• 出版日期2013-2