The formation of [C9H10]+˙ ions by loss of a molecule of water from molecular ions of 3-phenylpropanol with lifetimes of 10−11 to 10−5 s

Field ionization kinetic experiments in conjunction with deuterium labelling have been shown that the molecular ions of 3-phenylpropanol with lifetimes as short as 10^?11s lose a molecule of water via a specific 1,3 elimination. At times > 10^?11s two distinct hydrogen interchange processes in the molecular ions appear to complete with this reaction. One of the intechange processes involves the benzylic and hydroxylic hydrogen atoms and starts to complete with the elimination of water at shorter molecular ion lifetimes than the other interchange process in which the ortho hydrogen atoms also participate. Decomposing [C₉H₁₀]^+˙ ions generated by elimination of water from the molecular ions of 3-phenylpropanol or by direct ionization of various isomeric C₉H₁₀ compounds could not be distinguished adequately, illustrating isomerization either to a common ion structure or to a set of ions with rapidly interconverting structures. A consideration of the energetics of the elimination of water from 3-phenylpropanol suggests that at threshold energies 1-phenylpropene or indane type structures can be formed. Arguments for the latter have been obtained from the observation that a labile fluorine atom is present in the [M – H₂O]^+˙ ions generated from 3-pentafluoro-phenylpropanol.