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Elektronische Stabilisierung durch 7‐π‐Elektronen‐Konjugation in Heterocyclen Kristall‐ und Molekülstruktur eines inerten monocyclischen Radikalkations
Author(s) -
Hausen HansDieter,
Schulz Andreas,
Kaim Wolfgang
Publication year - 1988
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19881211126
Subject(s) - chemistry , steric effects , delocalized electron , radical , crystallography , electron delocalization , crystal structure , molecule , radical ion , stereochemistry , ion , organic chemistry
Electronic Stabilization Through 7‐π Electron Conjugation in Heterocycles. Molecular and Crystal Structure of an Inert Monocyclic Radical Cation The 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 (BPh 4 ). 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.