Studies of Thermodynamic Properties and Relative Stability of Polybrominated Xanthones by Density Functional Theory  

作　　者：单刚 李秀菊 王遵尧 杨郭英 

机构地区：[1]State Key Laboratory of Pollution Control and Resources Reuse,Department of Environment,Nanjing University [2]Department of Environmental Engineering,Jiangxi University of Science and Technology [3]Department of Biological and Chemical Engineering,Jiaxing University

出　　处：《Chinese Journal of Structural Chemistry》2010年第2期225-232,共8页结构化学（英文）

基　　金：Supported by the NNSFC (20737001, 20977046);NSF of Zhejiang Province (2008Y507280)

摘　　要：The thermodynamic properties of xanthone（XTH） and 135 polybrominated xanthones（PBXTHs） in the standard state have been calculated at the B3LYP/6-31G＊ level using Gaussian 03 program.The isodesmic reactions were designed to calculate the standard enthalpy of formation（△fHθ） and standard free energy of formation（△fGθ） of PBXTH congeners.The relations of these thermodynamic parameters with the number and position of Br atom substitution（NPBS） were discussed,and it was found that there exist high correlation between thermodynamic parameters（entropy（Sθ）,△fHθ and △fGθ） and NPBS.According to the relative magnitude of their △fGθ,the relative stability order of PBXTH congeners was theoretically proposed.The relative rate constants of formation reactions of PBXTH congeners were calculated,Moreover,the values of molar heat capacity at constant pressure（Cp,m） from 200 to 1000 K for PBXTH congeners were also calculated,and the temperature dependence relation of them was obtained,suggesting very good relationships between Cp,m and temperature（T,T^1 and T^2） for almost all PBXTH congeners.The thermodynamic properties of xanthone（XTH） and 135 polybrominated xanthones（PBXTHs） in the standard state have been calculated at the B3LYP/6-31G＊ level using Gaussian 03 program.The isodesmic reactions were designed to calculate the standard enthalpy of formation（△fHθ） and standard free energy of formation（△fGθ） of PBXTH congeners.The relations of these thermodynamic parameters with the number and position of Br atom substitution（NPBS） were discussed,and it was found that there exist high correlation between thermodynamic parameters（entropy（Sθ）,△fHθ and △fGθ） and NPBS.According to the relative magnitude of their △fGθ,the relative stability order of PBXTH congeners was theoretically proposed.The relative rate constants of formation reactions of PBXTH congeners were calculated,Moreover,the values of molar heat capacity at constant pressure（Cp,m） from 200 to 1000 K for PBXTH congeners were also calculated,and the temperature dependence relation of them was obtained,suggesting very good relationships between Cp,m and temperature（T,T^1 and T^2） for almost all PBXTH congeners.

关 键 词：polybrominated xanthone the number and position of Br atom substitution（NPBS） thermodynamic property relative stability molar heat capacity at constant pressure（Cp m） 

分 类 号：O621.2[理学—有机化学]