CH-pi Interaction between Carbohydrates and Aromatic Moieties: Electron Density Issue
| Autoři | |
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| Rok publikování | 2013 |
| Druh | Konferenční abstrakty |
| Fakulta / Pracoviště MU | |
| Citace | |
| Popis | Former studies of the CH-pi interactions between carbohydrates and aromatic moieties were focused on exploration of interaction energies in complexes of selected carbohydrates with benzene and naphthalene as simplest representatives of aromatic amino acids side chains. These studies provided complex insight into the nature and strength of carbohydrate-aromatic CH-pi interaction as well as its additivity with respect to total number of pi-electrons interacting it the aromatic system. The next logical step in complex study of CH-pi interaction is to study the influence of electron density in the aromatic system to the total interaction energy of the carbohydrate-aromatic complex. For this reason, we chose established set of selected carbohydrates mentioned above and constructed aromatic systems derivatives with expected increased and decreased electron density in the cycle – namely symmetrical difluoro-, trifluoro- and tetrafluoro-benzene and symmetrical diazine, triazine and tetrazine. All derivatives underwent electron-density evaluation in ring critical points by AIM analysis (MP2/aug-cc-pVTZ), which clearly shows decreasing electron density with respect to the degree of derivatization of fluorobenzenes and increasing electron density with respect to the degree of derivatization by nitrogens in the aromatic ring. With this set of molecules, we repeat the semiempirical SCC-DFTB-D potential energy scan with DFT-D BP/def2-TZVPP interaction energy refinement to identify stationary structures of potential energy surface. Their interaction energy is calculated after geometry optimization at DFT-D BP/def2 TZVPP level. Such level of theory has been previously proved to be sufficient and giving similar results as CCSD(T)/CBS method. |
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