Prediction of <i style="">pK</i>_a from basic principles: <i>Ab initio</i> and DFT studies on some molecules

Abstract

The quantum mechanical methodology based on the description of acid-base equilibrium for predicting <i style="">pK</i>_a of some selected molecules with the continuum model of solvent polarization is shown. The method is useful for predicting <i style="">pK</i>_a of selective molecules where the ionization of proton is basically controlled by the lone pair electrons of atomic site. However, it fails to predict <i style="">pK</i>_a of strong and very weak acids. The differences in the experimental and theoretically obtained values are negligible. The applicability of this theory for estimating <i style="">pK</i>_a values of molecules within the range of 4-5 is clearly demonstrated.