Publication Details |
| Category | Text Publication |
| Reference Category | Journals |
| DOI | 10.1002/jcc.21166 |
| Title (Primary) | Modeling the H bond donor strength of —OH, —NH, and —CH sites by local molecular parameters |
| Author | Schwöbel, J.; Ebert, R.-U.; Kühne, R.
; Schüürmann, G. |
| Source Titel | Journal of Computational Chemistry |
| Year | 2009 |
| Department | OEC |
| Volume | 30 |
| Issue | 9 |
| Page From | 1454 |
| Page To | 1464 |
| Language | englisch |
| Keywords | hydrogen bonding; Morokuma analysis; H-bond donor strength; Abraham parameter; local molecular reactivity; molecular hardness; effective donor energy; effective acceptor energy |
| Abstract | A quantum chemical model is introduced to predict the H-bond donor strength of monofunctional organic compounds from their ground-state electronic properties. The model covers —OH, —NH, and —CH as H-bond donor sites and was calibrated with experimental values for the Abraham H-bond donor strength parameter A using the ab initio and density functional theory levels HF/6-31G** and B3LYP/6-31G**. Starting with the Morokuma analysis of hydrogen bonding, the electrostatic (ES), polarizability (PL), and charge transfer (CT) components were quantified employing local molecular parameters. With hydrogen net atomic charges calculated from both natural population analysis and the ES potential scheme, the ES term turned out to provide only marginal contributions to the Abraham parameter A, except for weak hydrogen bonds associated with acidic CH sites. Accordingly, A is governed by PL and CT contributions. The PL component was characterized through a new measure of the local molecular hardness at hydrogen, (H), which in turn was quantified through empirically defined site-specific effective donor and acceptor energies, EEocc and EEvac. The latter parameter was also used to address the CT contribution to A. With an initial training set of 77 compounds, HF/6-31G** yielded a squared correlation coefficient, r2, of 0.91. Essentially identical statistics were achieved for a separate test set of 429 compounds and for the recalibrated model when using all 506 compounds. B3LYP/6-31G** yielded slightly inferior statistics. The discussion includes subset statistics for compounds containing OH, NH, and active CH sites and a nonlinear model extension with slightly improved statistics (r2 = 0.92). |
| Persistent UFZ Identifier | https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=605 |
| Schwöbel, J., Ebert, R.-U., Kühne, R., Schüürmann, G. (2009): Modeling the H bond donor strength of —OH, —NH, and —CH sites by local molecular parameters J. Comput. Chem. 30 (9), 1454 - 1464 10.1002/jcc.21166 |
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