EEVA (electronic eigenvalue): A new QSAR/QSPR descriptor for electronic substituent effects based on molecular orbital energies

A new descriptor of molecular structure for use in the derivation of predic tive QSAR and QSPR models, EEVA, is described. EEVA (Electronic Eigen Value ) is a modification of the recently proposed EVA approach, but it is based on computationally derived molecular orbital energies instead of vibrationa l frequencies. Like EVA, it is also invariant to alignment of the structure s concerned. EEVAs performance has been tested in different applications an d its predictive ability was clearly demonstrated. In particular, it seems to be suitable for 'pure' electronic substituent effects i.e., for cases in which both hydrophobic and steric factors are of minor importance.