Toward the accurate calculation of pKa values in water and acetonitrile.

摘要: We present a simple approach for the calculation of accurate pKa values in water and acetonitrile based on straightforward gas-phase absolute free energies acid conjugate base with use only continuum solvation model to obtain corresponding solution-phase energies. Most error such an arises from inaccurate differential which is removed our using correction realization that acidities have small systematic relative dominant solvation. The methodology outlined context set neutral acids as solvent reasonably electronic structure level theory (DFT), basis set, implicit model. It then applied comparison results three different hybrid density functionals illustrate insensitivity functional. Finally, sets protonated amine cationic both aqueous (water) nonaqueous (acetonitrile) solvents. shown generally predict all cases investigated within 1 pH unit so long larger than acidity calculations. Such rather general does not additional complications would arise cluster-continuum method, thus giving it strength high-throughput means calculate values. This article part Special Issue entitled: Metals Bioenergetics Biomimetics Systems.