[DFT study on the relationship between the structure and water solubility of dioxin compounds]

With DFT method of quantum chemistry, the electronic structures of all polychlorinated dibenzo-p-dioxins (PCDDs) and dibenzofurans (PCDFs) were fully optimized at the level of B3LYP/6-311G**, and the corresponding quantum parameters, viz. the mean polarizability(alpha), entropy(S) as well as the tensor components of polarizability and quadrupole moment (alpha(xx), alpha(yy), alpha(zz) and Q(xx), Q(yy), Q(zz)) and so on were used to the study on quantitative structure-property relationship (QSPR) of water solubility. And three QSPRs were successfully proposed on the basis of the internally consistent experimental values. The determination coefficients are 0.977, 0.968 and 0.961 respectively and the cross-validated correlation coefficients are 0.968, 0.959 and 0.946 respectively. It is indicated that water solubility of PCDD/Fs should mainly be related to the molecular volume, but much less influenced by the molecular interactions. And the differences of predicted values of QSPRs for the whole dioxins are probably related to the limited available experimental values and the characteristics of introduced variables. In comparison with the newly developed QSPR, the performance of QSPRs in this study is improved, which may attribute to both the precise calculations of electronic properties of PCDD/Fs by B3LYP/6-311G** and the introduction of tensor components of quadrupole moment into models.