Substituent effects on thermochemical properties of C-, N-, O-, and S-centered radicals. Physical interpretation of substituent effects

Substituent effects on ionization potentials and electron affinities of C-, N-, O-, and S-centered radicals were analyzed in terms of additive operational atomic contributions. The physical factors governing the estimated operational atomic parameters were analyzed in terms of fundamental atomic properties. The operational atomic parameters were found to depend on the electronegativity and the covalent radius which for each type of radical is described quantitatively by two separate sets of equations for ionization potentials and electron affinities, respectively.