<abstract xmlns="http://www.w3.org/1999/xhtml"> The theoretical pKa values of the derivatives of anilinium and pyridinium ions in 7 solvents are presented. For this purpose, the usage of isodesmic reaction scheme using the DFT/B3LYP approach with IEFPCM solvation was evaluated. We have shown that the suitable selection of reference species has the primary influence on the resulting data. For the studied anilinium ion derivatives the nonsubstituted anilinium ion seems to be a satisfactory reference system. The calculated values are in good accordance with the available experimental data with the RMS error of 1.00 and 0.99 pKa units in water and THF, respectively. The highest error in predicted pKa value is less than 2.0 pKa units in all cases. The chemical accuracy of the applied treatment is limited in the case of nitroaniline ions and the maximal therotetical uncertainty for derivatives of the pyridinium ion is within 2.1 pKa units. Our theoretical results enable us to predict the values of pKa for the solvents, where the experimental data are not completely available. Also the influence of the chemical structure on the accuracy of the applied method was discussed.</abstract>

The theoretical pKa values of the derivatives of anilinium and pyridinium ions in 7 solvents are presented. For this purpose, the usage of isodesmic reaction scheme using the DFT/B3LYP approach with IEFPCM solvation was evaluated. We have shown that the suitable selection of reference species has the primary influence on the resulting data. For the studied anilinium ion derivatives the nonsubstituted anilinium ion seems to be a satisfactory reference system. The calculated values are in good accordance with the available experimental data with the RMS error of 1.00 and 0.99 pKa units in water and THF, respectively. The highest error in predicted pKa value is less than 2.0 pKa units in all cases. The chemical accuracy of the applied treatment is limited in the case of nitroaniline ions and the maximal therotetical uncertainty for derivatives of the pyridinium ion is within 2.1 pKa units. Our theoretical results enable us to predict the values of pKa for the solvents, where the experimental data are not completely available. Also the influence of the chemical structure on the accuracy of the applied method was discussed.

The DFT calculations of pKa values of the cationic acids of aniline and pyridine derivatives in common solvents

Institute of Physical Chemistry and Chemical Physics, Slovak University of Technology, Radlinského 9, SK-812 37 Bratislava, Slovakia

Acta Chimica Slovaca

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The DFT calculations of pK values of the cationic acids of aniline and pyridine derivatives in common solvents

The theoretical pKa values of the derivatives of anilinium and pyridinium ions in 7 solvents are presented. For this purpose, the usage of isodesmic reaction...

The DFT calculations of pK_a values of the cationic acids of aniline and pyridine derivatives in common solvents

Published Online: May 27, 2014

Page range: 25 - 30

DOI: https://doi.org/10.2478/acs-2014-0005

Keywords
pKa, acid dissociation constant, DFT, B3LYP, IEFPCM, anilinium ion, pyridinium ion

© Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The DFT calculations of pKa values of the cationic acids of aniline and pyridine derivatives in common solvents

Published Online: May 27, 2014

Page range: 25 - 30

DOI: https://doi.org/10.2478/acs-2014-0005

KeywordspKa, acid dissociation constant, DFT, B3LYP, IEFPCM, anilinium ion, pyridinium ion

© Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava

This article is distributed under the terms of the Creative Commons Attribution Non-Commercial License, which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.

The DFT calculations of pK_a values of the cationic acids of aniline and pyridine derivatives in common solvents

Keywords
pKa, acid dissociation constant, DFT, B3LYP, IEFPCM, anilinium ion, pyridinium ion