Estimation of n-Octanol/water Partition Coefficients (lgK_(ow)) and the Aqueous Solubility (-lgS_w) of all PCDF Congeners by Density Functional Theory

摘要

Optimized calculation of dibenzofuran (DF) and 135 polychlorinated diben-zofurans (PCDFs ) was carried out at the B3LYP/6-31G~* level in GAUSSIAN 98 program. Based on the theoretical linear solvation energy relationship (TLSER) model, the obtained structural parameters were taken as theoretical descriptors to establish the novel quantitative structure-property relationship (QSPR) model for predicting n-octanol/water partition coefficients (lgK_(ow)) of PCDFs. The new model of lgK_(ow) achieved in this work contains three variables: energy of the highest occupied molecular orbital (E_(HOMO)), the most negative atomic partial charge (q~-) and average molecular polarizability (α), of which R~2= 0.9011 and SD = 0.17 with larger t values. In addition, the variation inflation factors (VIF) of variables in the present model are all less than 5.5, suggesting high accuracy of the lgK_(ow) model. And the results of cross-validation test (q~2 = 0.8688) and method validation also show this model exhibits optimum stability and better predictive power than semi-empirical method. At the same time, it is found that the aqueous solubility (-lgS_w) has high relative correlation with constant volume molar heat capacity (C_v~0), of which R~2 = 0.9777 and SD = 0.22. Moreover, lgK_(ow) and -lgS_w values of all PCDF congeners were predicted respectively.