Positive and negative ion mass spectra of Aryl‐ONN‐azoxy compounds containing electron withdrawing groups

Abstract

AbstractThe positive and negative ion mass spectra, at 70 eV, of p‐RC6H4N(O)NCOOCH3 (RH, Cl, Br, NO2), C6H5N(O)NCOOC2H5, p‐RC6H4N(O)NCONH2 (RH, Cl, Br, NO2) and p‐RC6H4N(O)NCOC6H5 (RH, Cl, Br, NO2) are reported. The azoxyester derivatives show abundant molecular ions and a number of weak fragment and rearrangement ions in the positive ion mass spectra, whereas weak molecular ions and abundant low mass fragment ions are present in the negative ion mass spectra. Similar behaviour is observed in the mass spectra of the azoxyamides. Conversely, for the azoxycarbonyl compounds the positive molecular ion is absent. A ready cleavage of the NCO bond occurs and only few fragments of low diagnostic value are formed, whereas the negative molecular ion is the base peak for all these compounds with the exception of the p‐NO2 derivative, where [MO]−⋅ is the base peak and [M]−⋅ is the second major ion. The behaviour under electron impact of these classes of compounds is compared with that of azoxycyanides reported previously.