摘要
基于密度泛函理论(density functional theory,DFT)对21种卤代苯化合物进行结构优化,并用最佳变量子集回归分析方法研究它们在鱼体内的生物富集因子(bioconcentration factors,B CF).在DFT方法的较高基组B3LYP/6-311G**(d,p)水平下,计算上述分子的平衡几何构型、前线轨道能、原子Mulliken电荷和热力学性质.研究发现,上述分子的lg B CF和次最低空轨道能(E NLUMO)、配分函数(lg Q)、苯环的第2个碳原子上净电荷(Q2)具有良好的线性关系.经逐一和逐五剔除交互验证,以及A C、K T和tα/2检验,所建构效关系(quantitative structure-activity relationship,QSAR)模型具有良好的稳健性和预测能力.根据所建QSAR模型建议卤代苯分子在鱼体内可能的生物富集机理.经热力学分析,卤代苯类化合物在鱼体内的生物富集过程中的焓变起到主要及正向作用,熵变(主要是疏水性作用)则起次要及负向作用.
The quantitative structure-activity relationship （QSAR） between structures and bioconcentration factors （Bcv） of 21 halogenated benzenes in fish was studied by using both density functional theory （DFT） and leaps-and- bounds regression analysis methods. The equilibrium geometries, the frontier molecular orbital energy, thermody- namic properties and Mulliken charges of atoms in these compounds have been calculated by the DFT method on the basis of the B3LYP/6-311G＊ ＊ （d,p） set. It is found that there are good linear relationships between the experimen- tal lg Bey for the molecules and the calculated parameters such as energy of the next lowest unoccupied molecular or- bital （E^LuMO）, partition function （lg Q）, net charge （Q2） of the second carbon atom in the benzene ring respec- tively. Based on the results of R^v_o2 , R^v_f2 of leave-one and five-out cross-validation, Akaike＇s information criterion （Ac ） and Kubinyi function （Kv） , t~/2, it is discovered that this established QSAR model has good stability and pre- dictability. The possible mechanism for the bioconcentration of halogenated benzenes in fish is thus proposed accord- ing to the QSAR model. On the basis of the thermodynamic analysis, enthalpy change plays a primary and positive role during bioaccumulation of halogenated benzene compounds in fish, however, entropy change （ mainly hydropho-bic interaction） plays a secondary and negative one.
出处
《深圳大学学报（理工版）》
EI
CAS
北大核心
2014年第1期96-102,共7页
Journal of Shenzhen University(Science and Engineering)
基金
国家自然科学基金资助项目(21075138)
环境模拟与污染控制国家重点联合实验室开放基金资助项目(13K02ESPCT)~~
关键词
计算化学
卤代苯
生物富集因子
密度泛函理论
热力学分析
构效关系
computational chemistry
halogenated benzene
bioconcentration factor
density functional theory （DFT）
thermodynamic analysis
quantitative structure-activity relationship （QSAR）
