title: Calculations of pKa of superacids in 1,2-dichloroethane.
abstract: Acidity calculations for some CH and NH superacids in 1,2-dichloroethane (DCE) were carried out using SMD and COSMO-RS continuum solvation models. After comparing the results of calculations with respective experimental pK(a) values it was found that the performance of SMD/M05-2X/6-31G* method is characterized by the mean unsigned error (MUE) of 0.5 pK(a) units and the slope of regression line of 0.915. The similar SMD/B3LYP/6-31G* approach was slightly less successful. The strong correlation over entire data set is confirmed by R(2) values of 0.990 and 0.984 for M05-2X and B3LYP functionals, respectively. The COSMO-RS method, while providing the value of the linear regression line slope similar to the corresponding values from SMD approach, characterized by rather loose correlation (R(2) = 0.823, MUE = 1.7 pK(a) units) between calculated and experimental pK(a) values in DCE solution.
authors: National Institute of Chemical Physics and Biophysics, 10 Rävala Blvd., Tallinn 10143, Estonia. aleksander.trummal@kbfi.ee
authors: Aleksander
authors: A
authors: Trummal
authors: Alar
authors: A
authors: Rummel
authors: Endel
authors: E
authors: Lippmaa
authors: Ivar
authors: I
authors: Koppel
authors: Ilmar A
authors: IA
authors: Koppel