Ionization of a series of p-halogen-substituted phenylethyl chlorides la-c under stable ion conditions gave via phenyl participation the corresponding 4-halo-a-ethylenebenzenium ions 2a-c. The stability of ions 2a-c is affected by the halogen atoms through their “back donation”. Similarly, ionization of 9-(2-fluoroethyl)-10-bromoanthracene (7) gave 9-(a- ethylene)-lO-bromoanthracenium ion 6 by similar anthryl group participation. Ionization of ...
