从头计算研究水溶液中有机化合物的pKa值  

Ab initio calculations of pKa values for some organic compounds in aqueous solution

作　　者：陈虹[1] 丁俊杰[1] 丁晓琴[1] 陈冀胜[1] 樊启平[2] 

机构地区：[1]北京药物化学研究所,北京102205 [2]防化指挥工程学院,北京102205

出　　处：《计算机与应用化学》2007年第5期580-582,共3页Computers and Applied Chemistry

摘　　要：运用量子化学方法计算水溶液中一些含氮小分子化合物和醇、酚、羧酸的pKa值。采取从头计算的Hartree-Fock法和6- 31G(d,p)基组,以及aug-cc-pVDZ基组,密度泛函理论的B3LYP法6-31G(d,p)基组,分别优化分子和离子的气相几何结构,采用极化连续介质模型模拟溶质和溶剂分子间的相互作用,不同方法和基组计算结果差别不大,18个化合物的均方根误差均为1．03,预测值与实验值的相关系数均为0．98,一致性较好。证明HF／6-31G(d,p)法和模型计算或预测含有相同官能团的小分子的pKa数值很合理,能够为研究药物分子体系的构效关系提供精确的pKa参数。The acidity constant of four kinds organic compounds in aqueous solution has been calculated by quantum chemical methods. Geometry optimizations were performed at Hartree-Fock SCF level, using 6-31G（d,p） basis sets and aug-cc-pVDZ basis sets, and at B3LYP level, using 6-31 G（ d, p） basis sets. The polarizable continuum model （PCM） was used to describe solute and solvent interac- tions. The results of using different methods and basis sets were similar. The RMS for all 18 compounds are 1.03, and r^2 =0.98. The model furnishes pKa values in relatively good agreement with experimental data. The result demonstrated that the PCM model and HF/ 6-31G（d,p） level calculations can reasonably predict the pKa of some similar compounds with the same functional group.

关 键 词：PKA PCM HF B3LYP 溶剂化能 

分 类 号：O641[理学—物理化学]