Theoretical Study on Ionization of Boric Acid in Aqueous Solution by Ab Initio and DFT Methods at T=298.15 K

Hoodad Ghanizadeh; Farhoush Kiani; Fardad Koohyar; Bahareh Khanlarzadeh

doi:10.4274/tjps.galenos.2018.26818

Theoretical Study on Ionization of Boric Acid in Aqueous Solution by Ab Initio and DFT Methods at T=298.15 K

Turk J Pharm Sci. 2020 Apr;17(2):177-181. doi: 10.4274/tjps.galenos.2018.26818. Epub 2020 Apr 24.

Authors

Hoodad Ghanizadeh¹, Farhoush Kiani¹, Fardad Koohyar^{2

3}, Bahareh Khanlarzadeh¹

Affiliations

¹ Department of Chemistry, Faculty of Science, Ayatollah Amoli Branch, Islamic Azad University, Amol, Iran.
² Division of Computational Physics, Institute for Computational Science, Ton Duc Thang University, Ho Chi Minh City, Vietnam.
³ Faculty of Applied Sciences, Ton Duc Thang University, Ho Chi Minh City, Vietnam.

Abstract

Objectives: The aim of this research work was to theoretically calculate the pK_a value of boric acid in aqueous solution by theoretical methods at T=298.15 K.

Materials and methods: Boric acid has antifungal and antiviral properties. It is used in various prescription pharmaceutical products. The ab initio and density functional theory (DFT) methods were used in this research work.

Results: To explain the determined acidic dissociation constant, the various molecular conformations and solute-solvent interactions of the species of boric acid were considered. The basis set at the B3LYP/6-31+G (d) level of theory was selected for DFT calculations. We analyzed the formation of intermolecular hydrogen bonds between several species of boric acid and water molecules through Tomasi's method.

Conclusion: The result showed that there was comparable agreement between the experimentally and theoretically determined pK_a values for boric acid.

Keywords: Boric acid; DFT; ab initio; acidic dissociation constant.