QSPR models for physicochemical properties of polychlorinated diphenyl ethers

Partial least squares regression together with 17 theoretical molecular structural descriptors was successfully used to develop QSPR models on sub-cooled liquid vapor pressures (P_L), n-octanol/water partition coefficients (K_OW) and sub-cooled liquid water solubilities (S_W,L) of polychlorinated diphenyl ethers (PCDEs). Only a few theoretical molecular descriptors were included in the QSPR models, including average molecular polarizability, molecular weight, total energy and standard heat of formation, which implies that intermolecular dispersive forces play an important role in governing the magnitude of P_L and K_OW. The models were tested as acceptable for prediction of P_L and K_OW by validation set. The consistency between observed and predicted values for P_L is the best, followed by K_OW and S_W,L. The Q_cum² values of the PLS models obtained are higher than 0.95, indicating high robustness of the models. Since P_L, K_OW and S_W,L values for many PCDE congeners are not available, the developed models can be used for estimation.