Reactivity Indices Profile: A Companion Tool of the Potential Energy Surface for the Analysis of Reaction Mechanisms. Nucleophilic Aromatic Substitution Reactions as Test Case
Journal of Organic Chemistry, 78 (3):
1091-1097 (2013)DOI: 10.1021/jo3025048
Abstract
We herein report on the usefulness of the reactivity indices profiles along a reaction coordinate. The model is tested to fully describe the reaction mechanism of the title reactions. Group nucleophilicity and electrophilicity profiles help describe the bond-breaking/bond-formation processes and the intramolecular electron density reorganization. The reactivity indices' profile analysis is consistently complemented with hydrogen bonding (HB) effects along the reaction coordinate: the final outcome of the reaction is determined by the stage at which the HB complex can be formed. Transition-state structures located for six reactions studied, including the charged nucleophile thiocyanate, show that the main stabilizing interaction is that formed between the hydrogen atom of the nucleophile and the o-NO2 group. This result discards the role of HB interaction between the nucleophile and the leaving group previously proposed in the literature.