基于密度泛函理论计算的多氯联苯毒性的定量结构-性质关系研究

Quantitative Structure-Property Relationship for Polychlorinated Biphenyls: Toxicity and Structure by Density Functional Theory

多氯联苯(PCBs)是一类人工合成的难降解有机物,疏水亲油、毒性大,引起了人们普遍关注.通过密度泛函理论(DFT)计算获得PCBs苯环上的负电荷密度(Q)、最低空轨道能量(ELUMO)、亲电指数(ω)等结构参数,并分析了PCBs毒性与其苯环间的共平面性、氯原子取代数(NCl)、Q以及ω等结构参数之间的关系.采用SPSS17统计软件分析了上述结构参数与PCBs毒性表征量正辛醇-水分配系数(KOW)的关联度,并构建lg KOW的多元线性回归方程.采用"交叉检验"方法检验所构建的lg KOW定量结构-性质关系(QSPR)方程的稳定性,并用于预测PCBs的毒性.由NCl和ω构造出的QSPR方程简单实用、可靠,PCBs的lg KOW计算值与实验结果吻合良好.

Polychlorinated biphenyls（PCBs） with hydrophobicity,lipophilicity and high toxicity,are a group of synthetic persistent organic contaminants,and have caused people widespread concern.In this work,density functional theory（DFT） was employed to calculate some structural parameters of PCBs,such as the negative charge density of the benzene ring（Q）,ELUMO,electrophilicity index（ω）,and the relationship of toxicity of PCBs with coplanarity,the number of substituted chlorines（NCl）,Q,and ω was also investigated.Using SPSS17 program,the relevancy of these structural parameters with n-octanol-water partition coefficients（KOW） was analyzed,and multiple linear regression equations of lg KOW for PCBs were constructed.Tests of these quantitative structure-property relationship（QSPR） equations were performed to ensure the stability using cross-validation method,and those equations were also used to predict the toxicity of PCBs.The established QSPR equation based on NCl and ω is simple and reliable,and the predicted lg KOWvalues of PCBs agree well with experimental results.