Ion-molecule reactions in alkyl cyanides: Identification of reactive hydrogen in precursor ions

The relative abundance of M + H]⁺ ions in the spectra of different nitriles depends on the nature of the nitrile. A new method for the identification of ion-molecule reactions has been applied, by determining the M + D]⁺ ion intensity with respect to the M + H]+ ion intensity in the spectra of partially deuteriated alkyl cyanides. This intensity ratio is correlated with the hydrogen-deuterium content of the suspected primary ions. In addition not only the reacting primary ions, but also the reactive hydrogen atom in the primary ion could be indicated. There is clear evidence that the proton attached to the nitrogen atom in the H₂C?C?N⁺˙? H rearrangement ion is transferred to the nitrile molecule.