Effects of the reaction environment on gas-phase proton-induced nucleophilic displacement at saturated carbon. Part 3

The H2O and D2O chem.-ionization mass spectra of MeF and MeCl were investigated at source temps. of 330-500 K and total pressures of 0.1-1.1 Torr. H3O+ ions, the reactant species formed that predominates in the source under the above conditions, promoted gas-phase nucleophilic substitution on the halogenated substrate by H2O, giving MeOH2+(H2O)n (n = 0-2) ions. These substitutions were prevented under ion-cyclotron-resonance conditions, providing direct evidence for contrasting ion reactivities under different exptl. conditions