FRAGMENTATION OF SOME EVEN-ELECTRON NITROAROMATIC IONS - QUESTION OF NITROTROPYLIUM ION

The behavior of the even‐electron mass 150 ions, (presumably nitrobenzoyl cations) generated by simple α‐cleavage of m‐ and p‐nitrobenzoic acid derivatives, undergo two competing secondary fragmentations to yield odd‐electron ions by the expulsion of NO and NO2. Expulsion of NO from the mass 150 ions from p‐nitro compounds is far greater than expulsion of NO from those generated from m‐nitro compounds. In addition, the behavior of the even‐electron mass 136 ions, generated from m‐ and p‐nitrobenzyl compounds, was compared to that of the mass 150 ions and they were found to decompose in a similar fashion. From our results we conclude that the decomposing mass 136 ions produced from either the m‐ or p‐nitrobenzyl compounds, or both, do not have the nitropylium structure; our data are more consistent with the decomposing ions having nitrobenzyl structures. Copyright © 1969 John Wiley & Sons, Ltd.