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采用Tomasi的极化统一模型对20种无机含氧酸HnROm在水相条件下进行从头算,选取14个量化参数结合含氧酸非羟基氧原子数等2个重要结构参数对含氧酸pK1进行逐步回归,引入非羟基氧原子数NO、非羟基氧原子净电荷数NCO、羟基氢原子净电荷数NCH(O)和氢氧间的重叠布居数POPR-O(H)4个参数建立QSPR方程,方程相关系数R为0.9946,且有F>Fα,表明方程回归效果显著;对回归系数的双边t检验结果均有P<0.05,表明此4个参数对pK1影响显著。对引入参数的物理意义及其对含氧酸pK1的影响分析表明,此4个参数均与羟基氧原子电子密度相关;其中NCH(O)和NO是影响含氧酸强度的主要因素,且NCH(O)的影响更大;NCO和POPR-O(H)则是影响含氧酸强度的次要因素,可用于区分各含氧酸强度的细微差别。此外,将NCH(O)、POPR-O(H)用于对35种酸碱进行分类也获得了良好的分类效果,表明此2个参数可用于区分R-O-H的电离方式。
The polar unified model of Tomasi was used for ab initio calculations of 20 inorganic oxoacids HnROm under aqueous conditions. The 14 oxoacid pK1 was selected by 14 quantitative parameters combined with two important structural parameters such as the number of non-hydroxy oxygen atoms of oxyacid Stepwise regression, the introduction of non-hydroxy oxygen atoms NO, the net number of non-hydroxy oxygen atoms NCO, the net number of hydroxyl hydrogen atoms NCH (O) and the number of overlapping OH-POPR-O (H) The correlation coefficient R of the equation and equation is 0.9946, and F> Fα, indicating that the regression equation of the equation is significant; both t-test results of regression coefficients have P <0.05, indicating that the four parameters have a significant effect on pK1. The physical meaning of the introduced parameters and its influence on the oxygen acid pK1 analysis showed that these four parameters are related to the electron density of hydroxyl oxygen atoms; NCH (O) and NO are the main factors affecting the strength of oxygen acids, and NCH (O); NCO and POPR-O (H) are secondary factors affecting the strength of oxyacid and can be used to distinguish the nuances of each oxyacid strength. In addition, NCH (O) and POPR-O (H) were also used to classify 35 kinds of acid-base. Good classification results were also obtained, indicating that these two parameters can be used to distinguish the ionization of R-O-H.