Borazines. Part V. The mass spectra of some 1,3,5-trialkylborazines

The mass spectra of a series of 1,3,5-trialkylborazines, B3H3N3R3(R = Et, Prn, Pri, Bun, Bu8, Bui, But) are reported and discussed. The dominant feature of the spectra is a group of ions which arise through cleavage of an alkyl radical from the α-carbon atom of an N-substituent in the molecular ion. These fragment species are isoelectronic with the benzyl or tropylium ions observed in the mass spectra of alkyl benzenes. Further fragmentation paths are described and are supported in the case of 1,3,5-triethylborazine by studies on deuteriated derivatives.