多溴吩噻嗪系列化合物的稳定性和热力学性质的密度泛函理论研究

用Gaussian 03程序, 在B3LYP/6-31G*水平上全优化计算了吩噻嗪和135个多溴吩噻嗪系列化合物(PBPTHs)在298.15 K和101.3 kPa状态时的热力学参数. 设计等键反应, 计算了PBPTHs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(NPBS)之间的关系. 结果表明: 多溴吩噻嗪的热能校正值(Eth)、恒容热容( )、标准熵( )、标准焓( )以及标准自由能( )与NPBS之间有很强的相关性(r2≥0.998). 在相关方程中, 溴原子的取代个数对多溴代吩噻嗪热力学数值的大小有很大影响. 根据 的相对大小, 从理论上求得异构体的相对稳定性顺序.

DFT Study on the Stability and Thermodynamic Properties of a Series of Polybrominated Phenothiazine

The thermodynamic properties of phenothiazine and 135 polybrominated phenothiazine (PBPTH) in the ideal gas state at 298.15 K and 101.3 kPa have been calculated at the B3LYP/6-31G* level using Gaussian 03 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 PBPTH congeners. The relationship of these thermodynamic parameters with the number and position of Br atom substitution (NPBS) was established, finding that there exists high correlation (r2≥0.998) of thermal correction to energy (Eth), heat capacity at constant volume ( ), entropy ( ), enthalpy ( ), free energy ( ), standard enthalpy of formation ( ), standard free energy of formation ( ) with NPBS. The number of Br atom substitution is the main factor, which has the greatest impact on the values of the thermodynamics properties. The stability of PBPTH congeners was theoretically proposed based on the relative magnitude of their .