Rank correlation of AM1 and PM3 derived molecular electrostatic potentials (RACEL) with Hammett σp-parameters

Abstract

Spearman non-parametric correlation coefficients obtained by comparison of the rank order of Hammett σ_p-parameters and the value of AM1 and PM3 derived molecular electrostatic potentials calculated for a range of para-substituted benzoic acids and amines show a chemically significant three-dimensional spatial distribution; the correlation is best for PM3, is improved for carboxylic acids by the inclusion of a solvent water molecule and is substantially decreased if point-charge derived electrostatic potentials are employed.