L. C. B. O.: An Easy Method to Predict Valence Ionization Energies. Application to Substituted Benzenes

Abstract

Abstract The linear combination bond orbitals (L.C.B.0.) MO treatment has been used to reproduce the π ionization energies of several ortho-, meta-and para-disubstituted benzenes. The Coulomb integral of the substituent π orbitals and their resonance integrals with the ring π orbitals have been obtained from the spectra of the corresponding monosubstituted benzenes, using the same procedure for all the compounds under examination. The ring Coulomb integrals have been chosen taking, as an internal standard, the experimental ionization energy value of the π[a2) orbital, non interacting by symmetry in the monosubstituted and in the para-disubstituted compounds. An application of this simple method to conformational analysis and to electron affinities is also shown.