Year: 2014
Type: article
Abstract: Aqueous pKa values of strong organic bases -DBU, TBD, MTBD, different phosphazene bases, etc -were computed with CPCM, SMD and COSMO-RS approaches.Explicit solvent molecules were not used.Direct computations and computations with reference pKa values were used.The latter were of two types: (1) reliable experimental aqueous pKa value of a reference base with structure similar to the investigated base or (2) reliable experimental pKa value in acetonitrile of the investigated base itself.The correlations of experimental and computational values demonstrate that direct computations do not yield pKa predictions with useful accuracy: mean unsigned errors (MUE) of several pKa units were observed.Computations with reference bases lead to MUE below 1 pKa unit and are useful for predictions.Recommended aqueous pKa values are proposed for all investigated bases taking into account all available information: experimental pKa values in acetonitrile and water (if available), computational pKa values, common chemical knowledge.
Source: Croatica Chemica Acta
DOI: 10.5562/cca2472
Authors: Karl Kaupmees, Aleksander Trummal, Ivo Leito
Language: English
Topic: Chemical Reaction Mechanisms
Subfield: Organic Chemistry
Field: Chemistry
Domain: Physical Sciences
Open Access status: diamond
OpenAlex ID: W2331119213