Substituent constants for predicting aromatic molecular quadrupole moments

Work in our group has shown a direct relationship between arene–cation binding enthalpies and the aromatic quadrupole moment (Θzz); the more negative the Θzz value, the greater the arene–cation binding enthalpy. The ability to predict aromatic Θzz values from the aromatic substitution pattern would therefore allow for the simultaneous prediction of the arene–cation binding enthalpy. Substituent constants were developed for the accurate prediction of Θzz values for mono-, di-, tri- and tetra-substituted aromatics. The Θzz values predicted from the developed substituent constants perform very well in determining relative arene–cation binding enthalpies.