QUANTITATIVE STRUCTURE–PROPERTY RELATIONSHIPS ON DISSOLVABILITY OF PCDD/Fs USING QUANTUM CHEMICAL DESCRIPTORS AND PARTIAL LEAST SQUARES

The environmental fate of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) has become a major issue in recent decades. Quantitative structure–property relationship (QSPR) modeling is a powerful approach for predicting the properties of environmental organic pollutants from their structure descriptors. In this study, QSPR models were established for estimating water solubility (- log SW) and n-octanol/water partition coefficient ( log KOW) of PCDD/Fs. Quantum chemical descriptors computed with density functional theory at the B3LYP/6-31G(d) level and partial least squares (PLS) analysis with an optimizing procedure were used to generate QSPR models for - log SWand log KOWof PCDD/Fs. Optimized models with high correlation coefficients (R2> 0.983) were obtained for estimating - log SWand log KOWof PCDD/Fs. Both the internal cross validation test [Formula: see text] and external validation test (R2> 0.965) results showed that the obtained models had high-precision and good prediction capability. The - log SW} and log KOWvalues predicted by the obtained models are very close to those observed. The PLS analysis indicated that PCDD/Fs with larger electronic spatial extent (Re), lower molecular total energy (ET), and smaller energy gap between the lowest unoccupied and the highest occupied molecular orbitals (ELUMO-EHOMO) tend to be less soluble in water but more lipophilic.