Prediction of n-octanol/water partitioning coefficients for selected metabolites of polybrominated diphenyl ethers by DFT method

A quantum chemical method has been developed to estimate the n -octanol/water partitioning coefficient (log K ow ) of metabolites of polybrominated diphenyl ethers (PBDEs). The data set covers 19 hydroxylated-PBDEs (HO-PBDEs) and 15 methoxylated PBDEs (MeO-PBDEs), with log K ow values varying from 4.63 to 7.67. The optimized ground-state geometries were calculated using density functional theory to quantify six quantum chemical descriptors. The resultant regression model through multiple linear regression had a correlation coefficient r 2 = 0.941 and a root-mean-square error rmse = 0.198. The polarizability and the most negative atomic partial Mulliken charge on a hydrogen atom were the most important parameters affecting the partitioning of the PDBEs between n -octanol and water. Simulated external validation and leave-10%-out cross-validation demonstrate the statistical robustness and prediction power of the derived model, which could be applied to predict log K ow values of HO-PBDE and MeO-PBDE congeners.