Assessment of various density functionals and solvation models to describe acid-base, spectral and complexing properties of thiobarbituric and barbituric acids in aqueous solution

Article type: Research Article

Authors: Lutoshkin, Maxim A.^{a; b; *} | Kazachenko, Alexandr S.^a

Affiliations: [a] Federal Research Center “Krasnoyarsk Science Center SB RAS”, Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, Russia | [b] Institut de Recherches sur la Catalyse et L’environnement de Lyon, Université de Lyon, Université Claude Bernard Lyon 1, IRCELYON, Villeurbanne, France

Correspondence: [*] Corresponding author: Maxim A. Lutoshkin, Federal Research Center “Krasnoyarsk Science Center SB RAS”, Institute of Chemistry and Chemical Technology SB RAS, Krasnoyarsk, Russia. E-mail: [email protected].

Abstract: The current research deal with ab initio calculations of equilibrium constants of stability or dissociation and some spectral properties of 2-thiobarbituric and barbituric acids. 11 DFT functionals (revTPSS, TPSSh, PBE, revPBE, M06-L, M06, M06-2X, M05-2X, M06-HF, CAM-B3LYP, X3LYP) with cc-pVDZ basis set were used for calculations of pKa,1 and pKa,2. For each of functionals the calculations were carried out for three solvation models – SMD, COSMO and C-PCM. It has been found that functionals containing 55% Hartree-Fock exchange (M06-2X and M05-2X) provide a better approach. The TD-DFT calculations show that revTPSS and TPSSh give accurate results for the description of the spectral characteristics. The revTPSS/CRNBL ECP/SMD level was tested for evaluating parameters of complex formation process these acids with La(III) for various computational models.

Keywords: Barbituric acid, thiobarbituric acid, DFT, TD-DFT

DOI: 10.3233/JCM-170745

Journal: Journal of Computational Methods in Sciences and Engineering, vol. 17, no. 4, pp. 851-863, 2017