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多溴苊烯是潜在的一类有机污染物,本文采用密度泛函理论在B3LYP/6-311G**水平上,优化这类化合物的分子几何结构135个,获得它们在理想气态的一些热力学性质的数值,研究这些性质与取代的溴原子数目和位置的关系,根据各异构体的标准生成Gibbs自由能的相对大小,求出它们热力学稳定性的顺序。结果表明:大部分多溴苊烯分子具有平面的几何构型。最稳定及最不稳定异构体的△_fH~θ及△_fG~θ,都随Br原子数目增加而逐渐增加。溴原子数目相同的△_fH~θ和△_fG~θ与溴原子的取代位置有很大的关系,其相对稳定性由分子内Br…Br核排斥作用的强弱而决定。
Polybrominated acenaphthylene is a potential organic pollutant. In this paper, 135 molecular geometries of these compounds were optimized by density functional theory at the B3LYP / 6-311G ** level, and some of their thermodynamic properties The relationship between these properties and the numbers and positions of substituted bromine atoms was studied. The relative sizes of Gibbs free energy were generated according to the standards of isomers, and the order of their thermodynamic stability was obtained. The results show that most of the molecules of PBB have a planar geometry. △ _fH ~ θ and △ _fG ~ θ of the most stable and the most unstable isomers increase with the increasing number of Br atoms. △ _fH ~ θ and △ _fG ~ θ of the same number of bromine atoms have a great relationship with the substitution position of bromine atoms, and their relative stability is determined by the strength of the intramolecular Br ... Br nuclear exclusion.