Correlation of Hammett's sgr;hyphen;Values with Electron Densities Calculated by Molecular Orbital Theory

摘要

It is shown that Hammett's &sgr;‐values can be correlated with electron densities calculated by the MO LCAO method. Since Coulomb and exchange integrals for atoms other than carbon are not accurately known, an absolute calculation of &sgr;'s is not possible. Nevertheless, &sgr;‐values permit derivation of a self‐consistent and reasonable set of parameters which can be used to calculate reasonable values for absorption frequencies, mesomeric moments, and orienting power of the substituents.