Comments on the Electrostatic Minimum Potential (Vmin) as a Measure of the Electron-Donating Power of PZ₃

In a recent publication, Suresh and Koga suggested that the molecular electrostatic potential minimum (V(min)) could be used as a quantitative measure of the "sigma donating power" of substituted phosphorus(III) ligands. In support of this assertion, they showed linear correlations between a number of physicochemical properties and V(min). Our examination of the analyses of the sets of experimental data used to support this assertion shows unequivocally that the variations in the properties cannot be described by a single parameter. Therefore, the utility of V(min) as a measure of the "sigma donating power" of substituted phosphorus(III) ligands remains unsubstantiated.