Study of the thermodynamic properties for polychlorinated 5,10-dihydrophenarsazine

摘要

136 polychlorinated 5,10-dihydrophenarsazine (PCPhZ) 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 thcir thermodynamic parameters were obtained.The isodesmic reactions were designed to calculate standard enthalpy of formation (△fHθ) and standard free energy of formation (△fGθ) of PCPhZ congeners.The relations of these thermodynamic parameters with the number and position of Cl atom substitution (Npcs) were discussed,and it was found that there exist high correlation between thermodynamic parameters (heat capacity at constant volume (Cvθ),entropy (Sθ),△fHθ and △rGθ) and Npcs.On the basis of the relative magnitude of their △fGθ,the order of relative stability of PCPhZ congeners was theoretically proposed.