对30种硝基芳烃化合物进行DFT-B3LYP/6-311G**水平全优化计算,据所得量子化学参数分类建立了硝基苯类和硝基苯胺类化合物对圆腹雅罗鱼急性毒性(-lgEC50)的定量构效关系(QSARs)模型 。结果表明,硝基苯类化合物的毒性主要由硝基基团的电荷(Q-NO2)和前线轨道能级差(△E)决定;硝基苯胺类化合物的毒性则由分子最低未占轨道能级(ELUMO)和△E决定 。苯环上取代基的类型、数目和取代位置直接影响到标题化合物的毒性大小,强吸电子基如硝基会降低Q-NO2和ELUMO大小,使化合物毒性增强,且邻对位硝基取代的毒性高于间位取代;相反,给电子基团氨基的存在则会使化合物的毒性降低 。总之,硝基是这两类化合物致毒的主要基团,将硝基包覆或还原为氨基应为此类化合物解毒的重要途径 。最后以1,4-二硝基苯为例,模拟了其活性亚硝基中间产物与蛋白质中还原性巯基间的反应,并将其与硝基苯和1,3-硝基苯的反应活化能进行了比较,讨论了不同取代基数目和位置对分子活性的影响,结果与QSAR模型分析一致,进一步验证了硝基芳烃化合物的致毒历程,研究结果对品优高能炸药的分子设计也有助益 。
The DFT-B3LYP method, with the basis set 6-311G**, was employed to calculate the molecular geometries and electronic structures of 30 nitroaromatics. E)touo, ELtJMO, EN)tOMO, ENLUMO, △E, Q-NO2, Qc(-NO2), Q-NH2, Qc(-NH2),μ and V were selected as quantum chemical descriptors. According to the type of substituents, the acute toxicity (-lg EC50) of these compounds to golden orfe fish along with the above descriptors was used to establish the quantitative structure-activity relationships (QSAR). The results indicate that the type and number of the substituents affect the toxicity of these compounds directly. A nitro group substitution increases the toxicity of the compounds, and on the contrary, an amido group substitution decreases their toxicity. For multi-nitrobenzenes, the toxicity of the o- or p-substituted nitrobenzene is bigger than that of the m-substituted one. In conclusion, the nitro group is the main toxic group for both nitrobenzenes and nitroanilines. Wrapping or reducing the nitro groups will decrease the toxicity of the subject chemicals. Finally, the reactions between the reactive nitroso intermediates of nitrobenzene, 1,3-dinitrobenzene, and 1,4-dinitrobenzene and a protein sulphydryl group were simulated, and the toxic action processes of nitroaromatics were pointed out concretely, The influence of different numbers and different positions of the substituents on the molecular activity was discussed. The results are consistent with QSAR analysis. This study will also be beneficial to the molecular design of high energetic explosives.