ION-NEUTRAL REORIENTATION AND UNIMOLECULAR LOSS OF ALKANES FROM ORGANIC IONS IN THE GAS-PHASE

The loss of alkanes from ionized aliphatic alkanes alcohols, ketones, ethers or amines takes place by a 1,2-elimination involving a C-C bond cleavage and th specific rearrangement of a hydrogen atom to the incipient radical. This reaction should normally occur within a limited distance between the reactant sites. This condition is accomplished with most probability during a concerted (or quasi-concerted) mechanism, before the completion of the C-C bond cleavage. The same reaction may also occur, however, in ion-neutral complexes, i.e. by a non-concerted mechanism, after the C-C bond cleavage is completed, provided that the probability is large enough for ion-neutral complexes to adopt suitable reactant configurations. This depends essentially on the proportion of possible reacting sites in the whole molecular ion.