多环芳烃典型电子性质与其大型蚤光致毒性的构效关系研究

多环芳烃(PAHs)是环境中广泛分布的持久性有毒有机污染物,备受研究者关注。基于密度泛函理论(DFT)先期计算PAHs前线分子轨道能隙可能与其光致毒性诱发所需吸收光照辐射能有一致性,本研究选取非取代PAHs对大型蚤(Daphnia magna)光致毒性实验数据,通过DFT计算典型电子性质,由偏最小二乘(PLS)分析方法优化发展了定量构效关系模型,经与前人结果比较和验证其拟合优度、稳定性和内外部预测性能均有显著提升,可在应用域(AD)范围内准确预测PAHs光致毒性而满足风险评估需求。构效关系分析结果表明,PAHs光致毒性与分子前线轨道能隙紧密相关,除苯并k]荧蒽和屈可能具有不同的光致毒性作用机制之外,多数PAHs若具有较低的前线轨道能隙、较小分子稳定性和较大分子变形性,均将有利于促进其光致毒性作用的发生;结合PAHs光致毒性与分子前线轨道能隙间的相关关系,可推测DFT计算前线轨道能隙宽度在2.740~4.208 e V之间和对应光照辐射波段约为295 nm~450 nm时,PAHs污染暴露将可能诱发较高的光致毒性效应。这为太阳光照射下PAHs光致毒性作用机制阐释和风险评价提供了数据支持与理论依据。

Investigation of Structure-Activity Relationship between Typical Electronic Properties and Phototoxicity of Polycyclic Aromatic Hydrocarbons to Daphnia magna

Polycyclic aromatic hydrocarbons (PAHs) pertain to the category list of persistent toxic substances which are ubiquitously detected in the environment and thereby arouse much concerns of scientific community. Based on the possible coherence of solar irradiation with the energy gap of molecular frontier orbitals by preliminary computation of density functional theory (DFT), in this study the experimental phototoxicity of PAHs to Daphnia Magna was selected in priori, and the corresponding quantitative structure-activity relationship (QSAR) between the typically DFT-calculated electronic properties and phototoxicity was carefully developed by partial least square (PLS) analyses. After critical validation and comparison with previous studies, the goodness of fitting, robustness and internal or external predictability was clearly enhanced to a certain degree. Thus, within the decided applicability domain (AD) the QSAR was suggested to serve as precise prediction tool to meet the demand of risk assessment. QSAR analysis indicated the tight correlation relationship of phototoxicity with energy gap of molecular frontier orbitals. And with the exception of benzok]fluoranthene and chrysene for different photoinduced toxicological mechanism, it is suitable for the great majority of PAHs that the lower energy gap of molecular frontier orbitals, the less molecular stability and higher deformability shall favor the occurrence of phototoxicity. In virtue of the correlation between energy gap of frontier orbitals and phototoxicity, the span of energy gap 2.740~4.208eV by DFT and the predicted corresponding wave spectrum of solar irradiation within about 295nm~450nm was proposed as the necessity of PAHs exposure to induce the higher phototoxicity. The study could be anticipated for providing data framework and theoretical guideline for phototoxicological mechanism illumination and risk assessment of PAHs under solar irradiation.