Abstract:

The thermodynamic properties of 75 polybrominated thianthrenes (PBTAs) in the ideal gas state at 298.15 K and 1.013 ×10⁵ Pa were calculated at the B3LYP/6-31G* level using Gaussian 98 program and their thermodynamic parameters were obtained.The isodesmic reactions were designed to calculate standard enthalpy of formation and standard free energy of formation of PBTAs congeners.The relations of these thermodynamic parameters with the number and position of Br atom substitution were discussed, and it was found that there existed high correlation between thermodynamic parameters (thermal correction to energy, heat capacity at constant volume, entropy,standard enthalpy of formation and standard free energy of formation) and number and position of Br atom substitution.On the basis of the relative magnitude of their standard free energy of formation, the order of relative stability of PBTA congeners was theoretically proposed.

Key words:

多溴噻蒽, 溴原子的取代位置和数目, 密度泛函理论, 热力学性质, 相对稳定性

摘要：

298.15 K和1.013 ×10⁵ Pa时,用Gaussian 98程序,在B3LYP/6-31G^*水平上计算了75个多溴噻蒽系列化合物(PBTAs),得到各分子的热力学性质。设计等键反应,计算了PBTAs系列化合物的标准生成热和标准生成自由能。同时研究了这些参数与溴原子的取代位置及取代数目之间的关系;结果表明：热能校正值、定容热容、熵、标准生成热、标准生成自由能与溴原子的取代位置及取代数目之间有很强的相关性。根据标准生成自由能的相对大小;从理论上求得异构体的相对稳定性顺序。

关键词:

多溴噻蒽, 溴原子的取代位置和数目, 密度泛函理论, 热力学性质, 相对稳定性