Computational study on the relative acidity of acetic acid by the QM/MM method combined with the theory of energy representation.
Computational study on the relative acidity of acetic acid by the QM/MM method combined with the theory of energy representation.
复制标题
DOI：
10.1021/jp066334d
复制
发表时间：
2007-01
期刊：
影响因子：
--
通讯作者：
Takumi Hori;Hideaki Takahashi;S. Furukawa;M. Nakano;Weitao Yang
中科院分区：
文献类型：
--
作者：
Takumi Hori;Hideaki Takahashi;S. Furukawa;M. Nakano;Weitao Yang
采用量子力学/分子力学（QM/MM）方法结合能量表象（ER）理论研究了乙酸水溶液的酸性。我们把注意力集中在分子相对于水溶剂的相对酸度DeltapK（a）上，以避免被称为质子的分子种类的溶剂化自由能的模糊性。采用B3 LYP泛函计算得到的气相自由能变化，计算得到乙酸的DeltapK（a）值为-11.5，与实验值-11.0非常吻合.结果表明，最近发展起来的QM/MM-ER方法对与有机分子酸碱性计算有关的溶剂化自由能给出了充分的描述。
We have applied the quantum mechanical/molecular mechanical (QM/MM) method combined with the theory of energy representation (ER) to study the acidity of acetic acid in aqueous solution. We have focused our attention on the relative acidity DeltapK(a) of the molecule with respect to water solvent to circumvent the ambiguity of the solvation free energies of the molecular species referred to as proton. The value of DeltapK(a) for the acetic acid has been computed as -11.5 when we adopt the free energy change in the gas phase obtained by the B3LYP functional, which is in excellent agreement with the experimental value of -11.0. It has been demonstrated that the QM/MM-ER approach recently developed gives an adequate description for the solvation free energies related to the acidity/basicity calculations of organic molecules.