Nucleophilic substitution of chlorobis(4-methoxyphenyl)methane: reactivity of carbenium ions in ILs-trifluoroethanol mixtures

The ionization of chlorobis(4-methoxyphenyl)methane (1-Cl) was performed in 1:1 mixtures of TFE/ILs (ILs = [emim][Tf2N], [bmim][Tf2N], [bpy][Tf2N]), and TFE/CH3CN. The decay of the immediately formed carbenium ion 1+ was followed by stopped flow, showing that the lifetime of this intermediate significantly decreases on going from CH3CN to [emim][Tf2N]. Ab initio calculations suggest an increase in the electrophilicity of the carbenium ion in ILs.