Site of Protonation in Aniline and Substituted Anilines in the Gas Phase: A Study via the Local Hard and Soft Acids and Bases Concept

Abstract

In this paper we address the long standing problem regarding the site for gas-phase protonation in aniline and substituted anilines. Our study reveals that DFT-based reactivity descriptors can reproduce the experimentally observed preferable protonation sites. However, it is found that the quantity / , termed “relative nucleophilicity” and a measure of “local polarizability”, produces more reliable results than the local softness, . The problem which sometimes arises in taking / as the reactivity descriptor is also discussed.