Chemical Reactivity Theory

Abstract

From 1933 ⁴³⁾, several theoretical approaches to the problem of the chemical reactivity of planar conjugated molecules began to appear, mainly by the Hückel molecular orbital theory. These were roughly divided into two groups⁴⁴⁾. The one was called the “static approach” ^43,45–48) and the other, the “localization approach” ^49,50).In 1952, another method which was referred to as the “frontier-electron method” was proposed ⁵¹⁾ and was conventionally grouped ⁵²⁾ together with other related methods ^53,54) as the “delocalization approach”Q.