Computational study on the relative acidity of acetic acid by the QM/MM method combined with the theory of energy representation

Takumi Hori, Hideaki Takahashi, Shin Ichi Furukawa, Masayoshi Nakano, Weitao Yang

Research output: Contribution to journalArticlepeer-review

23 Citations (Scopus)

Abstract

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 ΔpKa, 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 ΔpK 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.

Original languageEnglish
Pages (from-to)581-588
Number of pages8
JournalJournal of Physical Chemistry B
Volume111
Issue number3
DOIs
Publication statusPublished - 2007 Jan 25
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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