某些含氧酸中原子净电荷与pK_a的关系

Relationship Between Net Atomic Charges and pK_a Values of Some Oxygen-Containing Acids

在量子化学从头算 (分别采用HF/STO 3G ,HF/STO 3G ,HF/ 3 2 1G和MP2 /STO 3G)水平下 ,对 11种含氧酸分子 (H2 O ,H2 O2 ,HNO2 ,HNO3 ,HClO ,HClO2 ,HClO3 ,HCO2 H ,CH3 CO2 H ,HBrO和HIO)进行几何构型全优化和电子结构计算 ,将获得的电子结构数据与 pKa 实验值进行逐步回归分析 ,结果发现含氧酸中羟基氢原子净电荷、含氧酸中与羟基氧相连非氢原子净电荷两项与 pKa 呈良好的二元线性关系 。

The ab initio molecular orbital calculations at HF/STO3G, HF/STO3G**, HF/321G and MP2/STO3G level were adopted to study electronic structures of 11 oxygencontaining acid molecules including H2O,H2O2,HNO2,HNO3,HClO,HClO2,HClO3,HCO2H,CH3CO2H,HBrO and HIO. Results showed there exists multivariate significant correlation between the calculated net atomic charge of the atom linked to the hydroxyl group, of the hydrogen atom in the hydroxyl group and pKa values of the oxygencontaining acids. The net atomic charges play an important role in determining the acidity of the oxygencontaining acids.