中文摘要：

用30种硝基芳烃化合物DFT—B3LYP／6—311G＊＊全优化计算结构参数：最高占有和最低未占分子轨道能级（EHOMO和ELUMO）、次最高占有和次最低未占分子轨道能级（ENHOMO和ENLUMO）、前线轨道能级差（△E=ELUMO-EHOMO）、分子的总能量（ET）、硝基和硝基碳上净电荷（QNO2和QC-NO2）、与卤素相连碳原子上的净电荷（QC-X）、分子偶极矩（μ）和分子体积（V），结合文献中的疏水性参数（log Kow），按取代基类型和数目分类进行其对梨形四膜虫急性毒性（-log IC50）的定量构效关系（QSARs）研究．结果表明，前线轨道能级对硝基芳烃毒性作用有重要贡献，硝基芳烃对梨形四膜虫的毒性作用主要以与生物分子发生电子转移等化学反应为主，单硝基芳烃的毒性作用还与疏水性有关．卤素的存在增加了硝基芳烃化合物的毒性，卤素易被亲核取代．对30种标题物作多元线性回归，所得模型（-log IC50=18．037＋10．446QNO2，-41．323AE-20．471ENLUMO＋24．989ENHOMO，n=30，R=0．962，SE=0．185，F=78．640，Sig．=0．000）具有较高毒性预测作用．

英文摘要：

The DFT-B3LYP method, with the basis set 6-311G＊＊, was employed to calculate the molecular geometries and electronic structures of 30 nitroaromatics. EHOMO, ELUMO, ENHOMO, ENLUMO, △E, ET, QNO2, QC-NO2, QC-X, μ and V were selected as structural descriptors. According to the type and number of substituents, the acute toxicity （-log IC50） of such nitroaromatics to Tetrahymena pyriformis along with hydrophobicity quantified by the 1-octanol/water partition coefficient （log Kow） and the above eleven structural parameters, was used to establish the quantitative structure-activity relationships （QSARs）. The results indicate that the frontier orbital energies have important contributions to the toxicity of those nitroaromatics, and the electronic transfer interactions between the chemicals and biological molecules are the chiefly toxic actions of the nitroaromatics to the Tetrahymena pyriformis. For mononitro derivatives, their toxicities were correlated to log Kow too. The existence of halogen substituent may enhance the toxicities of such nitroaromatics. A highly predictive model was obtained for all objective compounds： -log IC50= 18.037＋ 10.446QNO2 -41.323△E-20.471ENLUMO＋24.989ENHOMO with n=30, R=0.962, SE=0.185, F=78.640, Sig.=0.000.