EFFECT OF MOLECULAR STRUCTURE ON IONIC DECOMPOSITION .2. AN ELECTRON-IMPACT STUDY OF 1,3- AND 1,4-CYCLOHEXADIENE AND 1,3,5-HEXATRIENE

Ionization and fragmentation schemes were constructed for 1,3- and 1,4-cyclohexadiene and 1,3,5-hexatriene through the use of energetic and metastable data. A value of 165 kcal/mole was obtained for the proton affinity of benzene from the heat of formation of the C6H7+ ion from the three C6H8 isomers. It was found that the greater part of the M – 1 and M – 2 ions from 1,3,5-hexatriene were of cyclic structure although a small portion of these may be acyclic. The C4H4+ ion from 1,4-cyclohexadiene and 1,3,5-hexatriene had a distinctly lower heat of formation than could be correlated to a linear ion and is suspected of being the cyclobutadiene ion. © 1969, American Chemical Society. All rights reserved.