Predicting the logKow of PCDFs with PM3 Quantum Chemical Descriptors

Restricted by experimental determination means，the establishment of quantitative structure-properties relationship（QSPR） from the existing n-Octanol/water partition coefficient（lgKow） experimental values of PCDFs. The geometrical optimization on 135 polychlorinated dibenzofurans（PCDFs）and dibenzofuran have been performed with the PM3 method included in G98W package. Job control is #p PM3 opt freq scf （conver=9）. The calculated molecular orbital energies and mulliken atomic charges of carbon atoms are used as structural descriptors for PCDFs. A quantitative equation between the logKow and the structural descriptors has been established with the multiple linear regression method. The best multiple regression coefficient is 0.9507，and the standard deviation is 0.737. The robustness of the model is verified to be excellent. The logKow of 85 PCDFs without experimental values is predicted with the model.