The role of the lifetimes of ion–neutral complexes in gas-phase electrophilic aromatic substitution

The gas-phase aromatic substitution occurring in the ion–neutral complex (INC) formed upon addition of arenium ions to proelectrophiles has been investigated by triple quadrupole mass spectrometry (TQMS). From measured cross-sections in experiments involving different arenium ions at various kinetic energy with numerous proelectrophiles, it was possible to ascertain the central role of the lifetime of INCs in dictating the efficiency of the substitution process.