Generation of Arenium Ions by a Self-Protonation Reaction in an Aprotic Molten Salt Medium

Article abstract of DOI:10.1021/ja00536a024

We have examined the reaction behavior of a group of polycyclic aromatic hydrocarbons in the aprotic liquid SbCl3-10 mol percent AlCl3 from 100 to 130 deg C by 1H NMR and by quench and separation techniques.For anthracene, pyrene, 9,10-dimethylanthracene, 9,10-diphenylanthracene, and naphthacene, we have observed a novel arene self-protonation reaction for which the proton source is the condensation-dehydrogenation of a portion of the arene combined with arene oxidation by SbCl3.Naphthalene and phenanthrene, however, do not undergo this reaction.Evidence is presented which indicates that the self-protonation reaction proceeds through the oxidation of the arene to its radical cation by SbCl3, and that the function of AlCl3 is to enhance the oxidizing power of the Sb₃₊/Sb₀ couple.