DFT Study on the Correlation between Thermodynamical Property and Molecular Structure of Polybromo-phenoxathiin

Complete optimization was conducted for 136 polybromo-phenoxathiin congeners (PBPTs) on the B3LYP/6-31G~* level with Gaussian 03 program. The structural parameters and thermodynamical parameters of each molecule were obtained under the standard state of 298.15 K and 1.013 × 10~5 Pa. Reverse linear regression was employed to establish the quantitative structure-property correlation models between heat capacity at constant volume (C_v~θ), entropy (S~θ),standard heat of formation (△_fH~θ) and standard free energy of formation (△_fG~θ) of PBPTs and the structural parameters (the most negative atomic charge (q~-) and molecular average polarizability (a)). These models presented better correlations (r~2＞ 0.97). And they were validated by variance inflation factor (VIF) and t-test, which can better explain the regularity of thermodynamical property of PBPTs, and has good stability and great prediction ability.