Chemical ionization and collisional activation spectra of α,β‐unsaturated nitriles

A study of the chemical ionization (CI) and collisional activation (CA) spectra of a number of α, β‐unsaturated nitriles has revealed that the even‐electron ions such as [MH] + and [MNH 4 ] + produced under chemical ionization undergo decomposition by radical losses also. This results in the formation of M + ˙ ions from both [MH] + and [MNH 4 ] + ions. In the halogenated molecules losses of X˙ and HX compete with losses of H˙ and HCN. Elimination of X˙ from [MH] + is highly favoured in the bromoderivative. The dinitriles undergo a substitution reaction in which one of the CN groups is replaced with a hydrogen radical and the resulting mononitrile is ionized leading to [M CN + 2H] + under CI(CH 4 ) or [M CN + H + NH 4 ] and [M CN + H + N 2 H 7 ] + under CI(NH 3 ) conditions.