叠氮化合物C6H6-n(N3)n(n=1-6)的密度泛函理论研究

DFT Theoretical Study on Nitrogen-rich Compounds C_6H_(6-n)(N_3)_n(n=1～6)

运用密度泛函理论,在B3LYP/6-31G*水平上,对叠氮化合物C6H6-n(N3)n(n=1～6)进行理论计算,并对所得到的几何结构进行了振动频率分析.计算结果表明,这些化合物是热力学稳定的.基于自然键轨道理论,分析了稳定结构的电荷分布及成键情况.在不破坏苯环和叠氮基的原则下,设计等键反应计算了这些化合物的生成热,结果表明,标题化合物的生成热都很高,且随着叠氮基数目的增加而线性增大.

The heats of formation （HOFs） were calculated for nitrogen-rich compounds C6 H6-n （ N3 ） n （ n = 1-6） , via density functional theory（DFT） with 6-31G^＊ basis set. We chose be nzene and HN3 as reference compounds in the process of designing isodesmic reactions. The relationship between the HOFs and the molecular structures is discussed. The results show that the HOFs of the title compounds linearly increase with increasing number of azide groups. The relative stabilities of the title compounds are discussed in terms of Mulliken charge, bond order, and the energy gaps between the frontier orbitals. All of the geometries of the title compounds were fully optimized without applying symmetry or structural constraints. This was accomplished via the default Gaussian convergence criteria. All of the optimized structures were characterized as true local energy minima on the potential energy surfaces, without imaginary frequencies.