Structural study of intermediate ions by kinetic energy release and thermochemical consideration: (C7H8N)+ ions from toluidine derivatives

The structures of the decomposing intermediate ions, [C7H8N]+ generated from a variety of toluidine and aniline derivatives were examined with the aid of kinetic energy release (KER).Among these ions, [C7H8N]+ ions generated from o-, m-, and p-toluidines and from 2, 3-, 3, 4-, and 2,6-xylidines are assigned to aminotropylium ion (a). The ions from o-, m-, and p-ethylanilines are interpreted as the corresponding aminobenzyl ion (b). A methyliminocy-clohexadiene ion structure (c) is postulated for the intermediate ion from N-methyl-o-, m-, and p-toluidines. The ion from N-ethylaniline is elucidated to be anilinomethene ion (d).These are in agreement with the results for the non-decomposing (stable) [C7H8N]+ ions, which were obtained by experimental heats of formation.