用Hartree-Fock法预测取代苯亚硒酸的pK_a值

Prediction of pK_a Value of Substituted Benzeneseleninic Acid by Hartree-Fock Method

采用Gaussion View软件用Hartree-Fock方法及STO-3G基组优化13种已知pK_a实验值的单取代苯亚硒酸化合物,得到它们的Mulliken电荷和NBO电荷,以羟基上的H1、O1原子及Se原子的Mulliken、NBO电荷分别对pK_a实验值做图,得到6个线性拟合方程,通过比较它们的相关性大小,R的绝对值越大,相关性越好,选出拟合效果最好的线性回归方程。再选取13种未知pK_a实验值的单取代和多取代苯亚硒酸化合物,算出各自的电荷,用该线性回归方程计算其pK_a值。结果表明,用O1原子的Mulliken电荷值与其实验pK_a值的线性回归方程,来预测未知取代苯亚硒酸的pK_a值具有良好的预测效果。

The Gaussion View was used to optimize the 13 monosubstituted bezene seleninic acids with known exp.pK_a values by using Hartree-Fock method and STO-3G× pop=（nbo）,their Mulliken charge and NBO charge were obtained. Using Mulliken charge or NBO charge of H1 atoms,O1 atoms and Se atoms on the oxhydryl and pK_a values, their relation diagrams were drawn, and 6 linear fitting equations were obtained. Through comparing their correlation levels（the greater the R value, the better the correlation）, the best quantum chemical equation was determined. Then13 monosubstituted or polysubtituted bezene seleninic acids with unknown pK_a values were chosen, and their charges were calculated, and the best equation was used to calculate their pK_a values. The results show that this method can well predict the pK_a of monosubstituted or polysubtituted bezene seleninic acids.