The 1,2,4,7-cyclooctatetraenyl radical (C8 H7 ) has been synthesized for the very first time via the bimolecular gas-phase reaction of ground-state carbon atoms with 1,3,5-cycloheptatriene (C7 H8 ) on the triplet surface under single-collision conditions. The barrier-less route to the cyclic 1,2,4,7-cyclooctatetraenyl radical accesses exotic reaction intermediates on the triplet surface, which cannot be synthesized via classical organic chemistry methods: the triplet non-aromatic 2,4,6-cyclooctatriene (C8 H8 ) and the triplet aromatic 1,3,5,7-cyclooctatetraene (C8 H8 ). Our approach provides a clean gas-phase synthesis of this hitherto elusive cyclic radical species 1,2,4,7-cyclooctatetraenyl via a single-collision event and opens up a versatile, unconventional path to access this previously largely obscure class of cyclooctatetraenyl radicals, which have been impossible to access through classical synthetic methods.
Keywords: gas-phase chemistry; mass spectrometry; reaction dynamics; reaction intermediates; single-collision conditions.
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