Quantitative structure–property relationships for octanol–air partition coefficients of polychlorinated biphenyls

Based on nine quantum chemical descriptors computed by PM3 Hamiltonian, using partial least squares analysis, a significant quantitative structure–property relationship for the logarithm of octanol–air partition coefficients (log K OA) of polychlorinated biphenyls (PCBs) was obtained. The cross-validated Q 2 cum value of the model is 0.962, indicating a good predictive ability. The intermolecular dispersive interactions and thus the size of the PCB molecules play a key role in governing log K OA. The greater the size of PCB molecules, the greater the log K OA values. Increasing E LUMO (the energy of the lowest unoccupied molecular orbital) values of the PCBs leads to decreasing log K OA values, indicating possible interactions between PCB and octanol molecules. Increasing Q Cl + (the most positive net atomic charges on a chlorine atom) and Q C − (the largest negative net atomic charge on a carbon atom) values of PCBs results in decreasing log K OA values, implying possible intermolecular electrostatic interactions between octanol and PCB molecules.