二英分子结构-水溶解度相关性密度泛函理论研究

运用密度泛函理论,在B3LYP/6-311G^**水平上,对多氯二苯并对二英(PCDDs)和多氯二苯并呋喃(PCDFs)的电子结构进行了优化,相应量子化学参数,即平均分子极化率(α)、熵(S)、极化率和四极矩的张量分量(α_xx、α_yy、α_zz和Q_xx、Q_yy、Q_zz)等用于该类化合物水溶解度的定量结构-性质相关性（QSPR）研究;基于内部误差一致的实验值,成功建立了3个QSPRs,其决定系数分别为0 .977、0 .968和0 .961;交叉验证相关系数分别为0 .968、0 .959和0 .946.模型分析表明,水溶解度主要与分子体积有关,而分子间相互作用的影响较小;不同QSPRs预测值间的差异可能与模型中预测变量本身性质和可获取实验值的有限性有关.与新近发展的QSPR相比较,本研究模型性能均有提高,这可能与B3LYP/6-311G^**精确计算电子性质和模型中引入四极矩张量分量有关.

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.