Studies in mass spectrometry. Part VIII. peri- and ortho-Effects in the mass spectra of some aromatic nitro-compounds

Abstract

The mass spectra of a number of aromatic nitro-compounds in which peri- and ortho-effects have an opportunity to operate have been determined. Interpretation of the spectra has been aided by extensive exact mass measurements and deuterium labelling. 1-Nitronaphthalene eliminates carbon monoxide from its molecular ion. o-Nitrobenzoic acid decarboxylates very readily upon electron impact, whereas the m- and p-isomers do not. The loss of a substituent from a position ortho to a nitro-group, with hydrogen rearrangement, yields C₆H₅NO₂⁺ ions whose structures vary with the nature of the departing substituent.