取代苯胺和苯酚类化合物土壤吸收系数的定量预测

Quantitative prediction of soil sorption coefficients of substituted anilines and phenols

基于定量结构-性质(QSPR)研究取代苯胺和苯酚的性质具有重要意义。对36种取代苯胺和苯酚类化合物进行DFT-B3LYP/6-311G**水平全优化计算。从中获得分子最高占用和最低空轨道能(E_(HOMO)和E_(LUMO))、分子次最高占用和次最低空轨道能(E_(NHOMO)和E_(NLUMO))、分子总能量(E_T)、氢原子所带的最高正电荷(q_H^+)、最负非氢原子的静电荷(Q^-)、分子偶极矩(μ)和分子体积(V)等描述符。结合文献中标题化合物的土壤吸收系数(log K_(oc))和疏水性系数(log K_(ow)),由多元线性回归方法建成QSAR模型,采用内外双重验证的办法,深入分析和检验模型的稳健性。最佳模型的复相关系数(R^2),去一法(LOO)交替检验复相关系数(R_(cv)~2),外部预测样本复相关系数(R_(ext)~2)分别为0.930,0.929和0.915,故所建QSPR模型的稳定性和预测能力良好。模型结果表明:标题化合物的log K_(oc)与疏水性系数(log K_(ow))、最负非氢原子的静电荷(Q^-)、分子次最低空轨道能(E_(NLUMO))和分子最高占用轨道能(E_(HOMO))的相关性较好。

Study on quantitative structure-property relationship （QSPR） of substituted anilines and phenols would be helpful in researching for their property. The DFT-B3LYP method, with the basis set 6-311G＊＊, was employed to calculate the molecular geometries and electronic structures of 36 substituted anilines and phenols. EHOMO, ELUMOo, ENHOMO, ENLUMO, ET, Qn＋, Q-, μ and V were selected as structural descriptors. The soil sorption coefficients （log Koc） of these compounds along with hydrophobicity described by log Kow, the above nine structural parameters, was used to established the quantitative structure-property relationships （QSPR） by multiple linear regression. The estimation stability and generalization ability of the model was strictly analyzed by both internal and external validation. The correlation coefficient （R2）, leave-one-out （LOO） cross validation R2cv, predicted values versus experimental ones of external samples R2ext of established the best model are 0.930, 0.929 and 0.915, respectively. These show that the QSAR model has both favorable estimation stability and good prediction capability. The results indicate that there is a good multivariate linear relationship between the soil sorption coefficients （log Koc） of substituted anilines and phenols and log Kow, Q-, ENLUMO, EHOMO.