Monohomocyclooctatetraene or cyclononatetraene anion radical

Abstract

The anion radicals of c/.s-bicyclo[6.1.0]nona-2,4,6-triene (I), rranj-bicyclo[6.1.0]nona-2,4,6-triene (II), and cw4-cyclononatetraene (III) have been prepared and their esr spectra measured. Comparison of the esr spectral data shows that I and III yield a species which is a nonclassical nine -electron, monohomocyclooctatetraene, while II produces an anion radical which is a classical seven -electron hexatrienyl system.Various homoaromatic species such as the trishomocyclopropyl cation (IV),3•4 the monohomotropylium cations (V),3•6 1,3-bishomocyclopentadienide anion (VI),3•6 and bicyclo[3.2.2]nonatrienyl anion (VII)3'7 with delocalized two, six, and eight -electron systems have been reported and discussed.Generally, in the field of electron spin resonance of organic paramagnetic species, attention has been focused on investigations of anionic, cationic, and neutral radicals of classical and systems. Prior to this work,1 the use of electron spin resonance spectroscopy as a tool in observation and investigation of the phenomenon of homoconjugation in odd electron systems had not been reported. The electron spin resonance investigation of the radical anions of certain seven and(1) Portions of this work have been published as communications:

Versuche zur Synthese von Nonafulvenen und von Nonaheptafulvalen

“…Rabinovitz & Gazit [13] sowie Gurratt & Knapp [14] isolierten einige hochanellierte Nonaheptafulvalene, die jedoch keine Ruckschliisse auf die Grundzustandseigenschaften des unbekannten Grundkorpers 5 erlauben. Anastassiou et al [18]: Der gemessene Wert von 246 nm bestatigt die cis-Arnordnung der Substituenten am Bruckenkopf von 10d.…”