Electron‐impact‐induced rearrangements of organic ions VI Unimolecular reactions of isomeric[C 8 H 9 ]+ions

Metastable ion spectra and deuterium labelling have been used to investigate a series of gaseous [C 8 H 9 ]+ ions of isomeric structures. The similarity of the intensities of their metastable loss of hydrogen, acetylene and ethylene molecules and metastable reactions of specifically labelled ions, suggests that the [C 8 H 9 ]+ reacting ions, formed initially with different structures, isomerise to a common structure or mixture of structures via deep‐seated rearrangement reactions which render all hydrogen atoms equivalent. The isomerisation process involved is controlled by a conversion of a vinyl bond into an allyl‐type bond, thus destroying the aromatic moiety.