DFT法研究取代芳烃对发光菌的急毒性

DFT study on substituted aromatic compounds' acute toxicities to Photobacterium

用DFT-B3LYP方法,分别在较高基组6-31G**和6-311G**水平下,全优化计算了24种卤苯、苯酚和苯胺衍生物。从中获得分子最高占用和最低空轨道能(EHOMO和ELUMO)、分子次最高占用和次最低空轨道能(ENHOMO和ENLUMO)、分子总能量(ET)、氢原子所带的最高正电荷(QH+)、最负原子的静电荷(Q-)、分子偶极矩(μ)和分子体积(V)等描述符。结合文献标题物对发光菌的毒性值(-lgEC50),由多元线性回归方法获得令人满意的QSAR模型,复相关系数R2和交叉验证系数Q2分别为0.9604和0.8946。模型结果显示:ELUMO越小,即最低空轨道能量越低,分子越易接受电子与亲核试剂发生反应,化合物对发光菌的毒性越大;分子的体积越大,μ越小,化合物毒性越大。

The DFT-B3LYP method,with the basis sets 6-31G＊＊ and 6-311G＊＊,was employed to calculate the molecular geometries and electronic structures of 24 substituted aromatic compounds,EHOMO,ELUMO,ENHOMO,ENLUMO,ET,QH＋,Q-,μ and V were selected as structural descriptors.The acute toxicity（-lgEC50） of these compounds to Photobacterium along with the above nine structural parameters,was used to established the quantitative structure-activity relationships（QSAR）.The variables were reduced using stepwise multiple regression method,and the statistical results indicate that the correlation coefficient in the multiple linear regression and cross validaton using leave-one-out were 0.9604 and 0.8946,respectively.Results show that the toxicity increases with the increase of molecular volume,and the decrease of the ELUMO and μ.