多取代苯胺溶解度和电离常数的单参数预测

摘要

Using Gaussion 09W software, the molecular structures of 10 kinds of aniline and its substituted aniline were simulated by using density functional method; Atomic charge NBO and Mulliken charge Mul of N and H atoms on aniline ring of polysubstituted aniline compounds were calculated. The results show that the charge has good single parameter correlation with experimental solubility coefficient pKs and experimental ionization equilibrium constant pKa.Quantified NBO/ Mulliken parameters were used to calculate unknown pKa value and unknown pKs value, two linear fitting of substitution of single parameter equation was carried out. The results show that and pKa/pKs predictive values obtained by the new method are close to those obtained by popular software ACD labs 6.0.%采用 DFT 理论方法与基组 B3LYP/3-21+G,模拟了 10 种单取代苯胺分子的骨架结构.计算了其苯胺环上氮和氢原子的自然轨道电荷(NBO)和密立根电荷(Mul)值.结果发现,该电荷值与其实验溶解度系数(pKs)和实验电离平衡常数(pKa)值间有好的单参数关联性.另外还计算了 10 个多取代基的苯胺分子的氮和氢原子的自然轨道电荷和密立根电荷参数,使用拟合出的两线性方程,结果显示新方法预测值与 ACD/Labs方法得到的多取代苯胺分子的 pKa /pKs 值接近.