Wiley InterScience Backfile Collection 1832-2000
Chemistry and Pharmacology
Electronic Stabilization Through 7-π Electron Conjugation in Heterocycles. Molecular and Crystal Structure of an Inert Monocyclic Radical CationThe 1,4-diethylpyrazinium (1) and -quinoxalinium (2) cation radicals are more stable than methylviologen and phenazinium radical cations and do not show association in concentrated solution or in the solid, as demonstrated by ESR and by a crystal structure analysis of 1(BPh4). Isolation of these unusually stable radical ions has been accomplished for the first time, their persistence stands in contrast to conventional conceptions of radical stabilization which involve either steric shielding or extensive π electron delocalization over many π centers.
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