Computational Studies Of Acidities Of Some Hydroxycoumarins

In this article, various computational approaches were applied to compute proton affinities, gas-phase acidities and aqueous acidities (pK(a) values) of some hydroxycoumarins. The results indicate that using the thermodynamic cycle involving proton transfer to hydroxide ion is the best method and linear Gibbs free energy relationship could be a trustworthy alternative. This work has improved the previous accuracies obtained and therefore, could be a reliable tool for pK(a) predictions of other hydroxycoumarins of interest. The pK(a) value of 5-hydroxycoumarin was predicted using the best approaches equal to 7.9.