The role of hyperconjugation in the unusual conformation of thymine: A natural bond orbital analysis
| Autor: | Sara Gómez, Emerson Rengifo, Frank Weinhold, Julio C. Arce, Albeiro Restrepo |
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| Rok vydání: | 2018 |
| Předmět: |
Steric effects
010405 organic chemistry Ab initio 010402 general chemistry Condensed Matter Physics Hyperconjugation Ring (chemistry) 01 natural sciences Biochemistry 0104 chemical sciences Thymine chemistry.chemical_compound Crystallography Delocalized electron chemistry Physical and Theoretical Chemistry Natural bond orbital Methyl group |
| Zdroj: | Computational and Theoretical Chemistry. 1130:58-62 |
| ISSN: | 2210-271X |
| DOI: | 10.1016/j.comptc.2018.03.005 |
| Popis: | The diketo conformation of thymine inferred from a high-level ab initio calculation, where one of the C H bonds of the methyl group lies in the ring plane eclipsing another C H bond instead of the polar C O bond, seems unexpected on the grounds of an analysis in terms of steric hindrance and long–distance inductive interactions. To assess the causes of such conformation, we carried out a natural bond orbital analysis. We found that charge delocalization (hyperconjugation), associated mainly with vicinal σC H( CH3) → σ∗C C(ring) and σC H( CH3) → π∗C C(ring) interactions, strongly favors the observed conformation. |
| Databáze: | OpenAIRE |
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