Theoretical studies on the electronic substituent effects

Abstract

There have been many attempts to separate the electronic effects of the substituents into the field(inductive) effects and resonance effects. To mention they are : Swain``s (F,R), Taft``s ($σ_I$, $σ_R$) and Charton``s ($σ_L$, $σ_D$). These field constants and resonance constants have a fairly good orthogonality each other. We carried out; i) factor analysis with orthogonality condition for ($σ_m$, $σ_p$, F, R) data set and confirmed the self consistency in this method. ii) two independent methods for predicting the field effect and resonance effect. First method is the one which predict the field constants fromthe result of MO calculations and the second method is the one which can obtain the resonance constants, from the orthogonality condition. It is found that the second method is consistent with the factor analysis with orthogonality condition.