Interaction of electron acceptors with bases—III : The absorption spectra of substituted polynitrobenzenes in liquid ammonia

Abstract

The visible region absorption spectra of a series of substituted polynitrobenzenes in liquid ammonia has been measured. It is suggested that the absorption is produced by the respective pentadienyl anion formed by the attachment of the amide ion to the ring carbon atom of the polynitrobenzene which is ortho or para to the maximum number of nitro groups. Such structures have been proposed by Bunnett as intermediates in aromatic nucleophilic substitution reactions. Of the compounds studied primary and secondary aromatic nitro-anilines are exceptional, in that ionization appears to occur by loss of a proton from the amino group.