ESR.-Untersuchungen an Radikal-Anionen des 1, 6-Imino-[10]annulens und seines N-Methyl-Derivats |
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Authors: | F. Gerson J. Heinzer E. Vogel |
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Abstract: | The ESR.-spectrum of the radical anion of 1,6-imino-[10]annulene (II) has been recorded. Its hyperfine structure reflects the reduced symmetry (Cs) of the molecule, as compared with that (C2v) of 1,6-methano- and 1,6-oxido-[10]annulenes (I and III, resp.). The coupling constants of the ring protons in II? are intermediate between the corresponding values of I? and III?. The ESR.-spectrum of the radical anion of 1,6-methylimino-[10]annulene (IV) has also been obtained, but not analysed in detail. The relative stabilities of the radical anions of the four bridged [10]annulenes are: I??II? > III? > IV?. The main secondary product identified by ESR.-spectroscopy after the decay of II?, III? and IV? is the naphthalene radical anion. A remarkable exception is IV, when reduced with sodium in 1,2-dimethoxyethane: in this case the ESR.-spectrum of the azulene radical anion is observed. |
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