DFT and Position of Cl Substitution (PCS) Methods Studies on n-Octanol/water Partition Coefficients

• 作 者: 谢亚杰 赵惠明 王遵尧 张雅荣
• 机 构: School of Biological and Chemical Engineering Jiaxing University,School of Biological and Chemical
• 出 处: 结构化学
• 发表日期: 2007年12期
• 关键词: PCDDs PCDD predictive inflation parent herein predicting substitution QSPR advan

Optimized calculations of 75 PCDDs and their parent DD were carried out at the B3LYP/6-31G* level by density functional theory (DFT) method. The structural parameters were obtained and significant correlation between the Cl substitution position and some structural parameters was found. Consequently, the number of Cl substitution positions was taken as theoretical descriptors to establish two novel QSPR models for predicting lgKow and –lgSw of all PCDD congeners. The two models achieved in this work contain two variables (Nα and Nβ), of which r = 0.9312, 0.9965 and SD = 0.27, 0.12 respectively, and t values are all large. The variation inflation factors (VIF) of variables in the two models herein are both less than 5.0, suggesting high accuracy of the lgKow and –lgSw predicting models, and the results of cross-validation test also show that the two models exhibit optimum stability and good predictive power. By comparison, the correlation and predictive ability of the present work are more advantageous than those obtained using semi-empirical AM1 and GC-RI methods.

Optimized calculations of 75 PCDDs and their parent DD were carried out at the B3LYP / 6-31G * level by density functional theory (DFT) method. The structural parameters were obtained and significant correlation between the Cl substitution position and some structural parameters was found. The number of Cl substitution positions was taken as theoretical descriptors to establish two novel QSPR models for predicting lgKow and -lgSw of all PCDD congeners. The two models achieved in this work contain two variables (Nα and Nβ), of which r = 0.9312, 0.9965 and SD = 0.27, 0.12 respectively, and t values ​​are all large. The variation inflation factors (VIF) of variables in the two models herein are both less than 5.0, suggesting high accuracy of the lgKow and -lgSw predicting models, and the results of cross-validation test also show that the two models exhibit optimum stability and good predictive power. By comparison, the correlation and predictive ability of the present work are more advantageous than those obtained using semi-empirical AM1 and GC-RI methods.