Caballero-García, G.; Mondragón-Solórzano, G.; Torres-Cadena, R.; Díaz-García, M.; Sandoval-Lira, J.; Barroso-Flores, J. Calculation of VS,max and Its Use as a Descriptor for the Theoretical Calculation of pKa Values for Carboxylic Acids. Molecules2019, 24, 79.
Caballero-García, G.; Mondragón-Solórzano, G.; Torres-Cadena, R.; Díaz-García, M.; Sandoval-Lira, J.; Barroso-Flores, J. Calculation of VS,max and Its Use as a Descriptor for the Theoretical Calculation of pKa Values for Carboxylic Acids. Molecules 2019, 24, 79.
Caballero-García, G.; Mondragón-Solórzano, G.; Torres-Cadena, R.; Díaz-García, M.; Sandoval-Lira, J.; Barroso-Flores, J. Calculation of VS,max and Its Use as a Descriptor for the Theoretical Calculation of pKa Values for Carboxylic Acids. Molecules2019, 24, 79.
Caballero-García, G.; Mondragón-Solórzano, G.; Torres-Cadena, R.; Díaz-García, M.; Sandoval-Lira, J.; Barroso-Flores, J. Calculation of VS,max and Its Use as a Descriptor for the Theoretical Calculation of pKa Values for Carboxylic Acids. Molecules 2019, 24, 79.
Abstract
Theoretical approaches to calculate pKa values for Brønsted acids is a challenging task that, most of the time, involves sophisticated and time-consuming methods. Therefore, heuristic approaches are efficient and appealing methodologies to approximate these values. Herein, by considering the electrostatic potential on acidic hydrogen atoms in a similar fashion that a σ–hole is defined, we calculated the maximum surface potential, VS,max, and used it as a descriptor to correlate it with experimental acidity constants. These values were calculated using the CPCM implicit solvent model (water) with six different methods: five density functionals and the Møller–Plesset second order perturbation theory. Six different basis sets were combined with each method in order to benchmark a total of thirty-six levels of theory. Overall, 1080 calculations were performed and found to correlate with experimental data. The ωB97X-D/6-31+G(d,p) level of theory stands as the best one for consistently reproduce the reported pKa values.
Keywords
pKa; hydrogen bond; σ–hole
Subject
Chemistry and Materials Science, Physical Chemistry
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
