Aromaticity: A new Multilinear Approach

Six equations obtained by multiple regression analysis were developed to characterize aromaticity of alternant and nonalternant hydrocarbons. Three equations are applicable to alternant systems, three to nonalternant systems. The quantities used in the equations are the various experimental and theoretical (HMO and SCF-MO) data reflecting aromatic behavior of delocalized π–electron systems. The aromaticity index, AI, is given as a numerical value and the equations can be used to predict aromaticity of various compounds on a quantitative basis.