Mechanistic pathways of aromatic nucleophilic substitution in conventional solvents and ionic liquids

Abstract

Solvation effects on the reaction mechanism of the title reactions have been kinetically evaluated in 21 conventional solvents and 17 ionic liquids. Solvent polarity affects the catalyzed and non-catalyzed SNAr pathways differently. The ambiphilic character of water and formamide, which act as a hydrogen bond donor/acceptor, induces nucleophilic activation at the nitrogen center of the nucleophile. The ionic liquid EMIMDCN appears to be the best solvent for the SNAr route probably due to the high polarizability of the dicyanamide anion.