Henri E. Audier, Philippe Mourgues, Danielle Leblanc and Steen Hammerum,
Compt. Rends. Acad. Sci. II, 317, 27 (1993)
ionized ketones, where the ketone molecular ions appear to be transformed into isomers (the McLafferty intermediates), in which the incipient enol ion is only loosely bonded to the alkene, and the latter is in turn easily displaced by (different) alkene neutrals;
beta-distonic ions, where the water molecule in the beta-distonic isomer of ethanol is easily displaced by another water molecule (demonstrated by exchange with O-18 labeled water) or by methanol, and the methanol in the beta-distonic isomer of methyl ethyl ether is easily displaced by another methanol; the distonic ions behave as solvated ethylene radical cations;
oxonium ions, where e.g. propylated formaldehyde (the product of alpha-cleavage in dipropyl ether molecular ions) undergoes exchange of propene neutrals, as if the propylated formaldehyde were in fact a loosely bonded complex of propene and protonated formaldehyde.
The experimental observations were made using FT-ICR spectrometry.