{'fraction_non_alphanumeric': 0.06129807692307692, 'fraction_numerical': 0.015625, 'mean_word_length': 4.238993710691824, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 1, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Concerted chain isomerization in protonated alkylbenzenes

The first step in the unimolecular reaction of metastable protonated alkylbenzenes is the stretching of the C(benzene)−C(α) bond. Therefore, the intermediacy of a π-complex [C 6 H 6 , alkyl + ] has often been proposed. In this work, the kinetic energy releases associated with the [tert-alkyl] + product were measured for a large number of [C 6 H 6 −C n H 2n+1 + ] (n > 3) ions. At least for β-branched alkylbenzenes, it is shown that the chain isomerization which occurs prior to dissociation involves neither the [C 6 H 6 , C n H 2n+1 + ] π-complex nor a [C 6 H 7 + , alkene] ion-neutral complex. The data are explained by a concerted process in which the stretching of the C(benzene)−C(α) bond is accompanied by the migration of the tertiary β-hydrogen from C(β) to C(α)