pKa Calculation of Coumarin Derivatives in Aqueous Solution: A Theoretical Approach

pKa Calculation of Coumarin Derivatives in Aqueous Solution: A Theoretical Approach

In this work, calculation of pKa values has been performed on the 3-hydroxycoumarin, 4-hydroxycoumarin, 6-hydroxycoumarin and 7-hydroxycoumarin drugs in aqueous solution. Gas-phase energies were calculated at the B3LYP/6-31+G(d) level of theory. Free energies of solvation were calculated by applying the conductor-like polarizable continuum model (CPCM) solvation model at the PBE1PBE/6-31G(d) level of theory. The CPCM calculations were employed with the UAHF, UAKS, Bondi and Pauling atomic radii. By comparing the calculated pKa’s for 3-hydroxycoumarin, 4-hydroxycoumarin, 6-hydroxycoumarin and 7-hydroxycoumarin drugs from various methods to their experimental values, it was found an optimal combination of methods for gas and solution phase energies.

In this work, calculation of pKa values has been performed on the 3-hydroxycoumarin, 4-hydroxycoumarin, 6-hydroxycoumarin and 7-hydroxycoumarin drugs in aqueous solution. Gas-phase energies were calculated at the B3LYP/6-31+G(d) level of theory. Free energies of solvation were calculated by applying the conductor-like polarizable continuum model (CPCM) solvation model at the PBE1PBE/6-31G(d) level of theory. The CPCM calculations were employed with the UAHF, UAKS, Bondi and Pauling atomic radii. By comparing the calculated pKa’s for 3-hydroxycoumarin, 4-hydroxycoumarin, 6-hydroxycoumarin and 7-hydroxycoumarin drugs from various methods to their experimental values, it was found an optimal combination of methods for gas and solution phase energies.