The expulsion of alkyl radicals from the methyliumylaminomethyl radical cation, ^.CH₂NH₂CH₃⁺, and related distonic ions

The dissociation of metastable ^.CH₂NH₂CH₃⁺ ions into CH₃^. and CH₂=NH₂⁺ is accompanied by a remarkably high translational energy release, demonstrating that the addition of a methyl radical to the N-terminus of CH₂=NH₂⁺ has an appreciable energy barrier. Isotope labelling shows the reaction to be highly specific. Alkyl radical loss from a number of substituted α-distonic ions was also examined; the kinetic energy release accompanying loss of ethyl radicals from N-ethyl α-distonic ions, CH₃CH₂N⁺H₂ĊHR, varies with the nature of R. The energy barrier for dissociation and the relative energies of the five C₂H₇N^.+ isomers was examined with the G2(MP2) and CBS-Q composite theoretical methods.