NaturalJcoupling (NJC) analysis of the electron lone pair effect on NMR couplings: 2. The anomeric effects on1J(C, H) couplings and its dependence on solvent
| Autor: | O. E. Taurian, Juan E. Peralta, Rubén H. Contreras, Veronica Barone, Daniel Zaccari, James P. Snyder |
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| Rok vydání: | 2002 |
| Předmět: | |
| Zdroj: | Molecular Physics. 100:705-715 |
| ISSN: | 1362-3028 0026-8976 |
| DOI: | 10.1080/00268970110091862 |
| Popis: | The electronic origin of the influence of the anomeric effect (negative hyperconjugative interaction, NHI) on the Fermi contact (FC) term of 1 J(C, H) couplings has been studied from a theoretical point of view at the DFT-B3LYP level. The HN=CH2, molecule was chosen as the primary model compound, in which both FC 1 J(C, H) couplings were decomposed into bond contributions with the natural J coupling dissection approach (NJC). Differences between the 1 J (C, H)FC couplings for C——H bonds in synperiplanar and antiperiplanar orientations with respect to the nitrogen non-bonding electron pair closely follow the experimental trend. They are made up chiefly of three NJC contributions: ‘bond’, ‘direct lone pair’ and the ‘carbon-core orbitals’. The NHI influence on these terms was studied by applying the natural bond orbital (NBO) deletion procedure to the charge transfer interaction into the antiperiplanar (C——H) antibond (n(N)→(C——H)∗) prior to the NJC dissection calculation. The dielectric solvation effect on ... |
| Databáze: | OpenAIRE |
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