Solvent effects on chemical reactivity

Abstract

Typical examples for different types of solvent effects on chemical reactivity are given, e. g. solvent effects on reaction rates, on the position of chemical equilibria, on competitive reaction mechanisms, on dichotomic reaction paths, on chemoselectivity, and on stereoselectivity. According to their solvent sensitivity, most organic reactions can be classified into dipolar transition-state reactions, isopolar transition-state reactions, and free-radical transition-state reactions, typical examples of which are given. Attempts to describe the solvation capability by virtue of empirical parameters of solvent polarity are mentioned. Particular attention is merited by the ET(30)-parameter, an empirical parameter derived from a negatively solvatochromic pyridinium-N-phenolate betaine dye as reference compound. Some examples of the application of this ET(30)-scale to solvent-sensitive chemical reactions are given. © 1982, Walter de Gruyter. All rights reserved.