Predicting pK(a) values of substituted phenols from atomic charges: Comparison of different quantum mechanical methods and charge distribution schemes
| Authors | |
|---|---|
| Year of publication | 2011 |
| Type | Article in Periodical |
| Magazine / Source | Journal of Chemical Information and Modeling |
| MU Faculty or unit | |
| Citation | |
| Field | Physical chemistry and theoretical chemistry |
| Keywords | pka; pka prediction; charge; QSPR; population analysis; quantum meechanics |
| Description | The acid dissociation (ionisation) constant pKa is one of the fundamental properties of organic molecules. We have evaluated different computational strategies and models to predict the pKa values of substituted phenols using partial atomic charges. Partial atomic charges for 124 phenol molecules were calculated using 83 approaches containing seven theory levels, three basis sets and five population analyses. The correlations between pKa and various atomic charge descriptors were examined and the best descriptors were selected for preparing the QSPR models. One QSPR model was created for each of the 83 approaches to charge calculation, and then the accuracy of all these models was analyzed and compared. The pKas predicted by most of the models correlate strongly with experimental pKa values. All seven examined theory levels are applicable for pKa prediction from charges. The best results were obtained for the MP2 and HF level of theory. The most suitable basis set was found to be 6-31G*. |
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