Eckert, Frank and Leito, Ivo and Kaljurand, Ivari and Kuett, Agnes and Klamt, Andreas and Diedenhofen, Michael (2009) Prediction of Acidity in Acetonitrile Solution with COSMO-RS. JOURNAL OF COMPUTATIONAL CHEMISTRY, 30 (5). pp. 799-810. ISSN 0192-8651,
Full text not available from this repository. (Request a copy)Abstract
The COSMO-RS method, a combination of the quantum chemical dielectric continuum solvation model COSMO with a statistical thermodynamics treatment for realistic solvation simulations, has been used for the prediction of pK(a) values in acetonitrile. For a variety of 93 organic acids, the directly calculated values of the free energies of dissociation in acetonitrile showed a very good correlation with the pK(a) values (r(2) = 0.97) in acetonitrile, corresponding to a standard deviation of 1.38 pK(a) units. Thus, we have a prediction method for acetonitrile pK(a) with the intercept and the slope as the only adjusted parameters. Furthermore, the pK(a) values of CH acids yielding large anions with delocalized charge can be predicted with a rmse of 1.12 pK(a) units using the theoretical values of slope and intercept resulting in truly ab initio pK(a) prediction. In contrast to our previous findings on aqueous acidity predictions the slope of the experimental pK(a) versus theoretical Delta G(diss) was found to match the theoretical value I/RT In (10) very well. The predictivity of the presented method is general and is not restricted to certain compound classes. However, a systematic correction of -7.5 kcal mol(-1) is required for compounds that do not allow electron-delocalization in the dissociated anion. The prediction model was tested on a diverse test set of 129 complex multifunctional compounds from various sources, reaching a root mean square deviation of 2.10 pK(a) units. (C) 2008 Wiley Periodicals, Inc. J Comput Chem 30: 799-810, 2009
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DIMETHYL-SULFOXIDE SOLUTION; DENSITY-FUNCTIONAL THEORY; POLARIZABLE CONTINUUM MODEL; THEORETICAL AB-INITIO; PROTON AFFINITY; 1ST-PRINCIPLE PREDICTIONS; ORGANIC SUPERBASES; AQUEOUS-SOLUTION; HIGH BASICITY; PK(A) VALUES; pK(a); acetonitrile; acidity; COSMO; COSMO-RS; density functional theory |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 18 Sep 2020 06:20 |
| Last Modified: | 18 Sep 2020 06:20 |
| URI: | https://pred.uni-regensburg.de/id/eprint/29125 |
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