Substituent Effect on the Structure of the Phenonium Ion

Abstract

An ab initio MO calculation is made for the substituent (X) effect on the phenonium ion, X-C6H4C2H4+ and C6H5C2H4-n(-Me)n+. The electron-donating group X on para position strengthens the bridge bond, while the electron-withdrawing group weakens it. The trend is interpretable in terms of the C6H4X+ → C2H4 back charge transfer. The methyl groups attached to the C2H4 site deform considerably the structure. They give the intermediate geometries in the “symmetric bridge-asymmetric open” spectrum. © 1986, The Chemical Society of Japan. All rights reserved.