Nitrogen elimination in the mass spectra of diphenyl and triphenyl‐v‐triazoles

The mass spectra of seven v‐triazoles (I to VII), having two or three phenyl substituents in 1, 4 and 5 positions, are described. Differences in the rate of nitrogen elimination from themolecular ions of I to III and IV to V are explained by the statement that this reaction requires a higher energy of activation for the transition state in IV to V than in I to III. At high electron voltages the relative intensities of fragment ions and metastable ions are very similar in the mass spectra of 1,4,5 triphenyl‐v‐triazole (I) and the ketenimine (VIII). Differences in the low electron voltage spectra of I and VIII, and energy measurements, however, show that probably an azirine ion IX is involved in the formation of the [M‐N2]+ ion from I. It is shown that production of the rearrangement ion m/e 165 (C13H9) isa high energy process.