Stereochemical dependence of NMR geminal spin-spin coupling constants
In this work it was sought to explore the versatility of germinal spin–spin coupling constants, ²JxySSCCs, as probes for stereochemical studies. A set of compounds, where their experimental ²JxySSCCs through the X–C–Y molecular fragment are predicted to be sensitive to hyperconjugative interactions...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2008 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/24680 |
| Acceso en línea: | http://hdl.handle.net/11336/24680 |
| Access Level: | acceso abierto |
| Palabra clave: | Geminal Couplings Nmr Fermi Contact Stereochemistry Geminal Spin–Spin Coupling Constants Stereochemical Analysis https://purl.org/becyt/ford/1.3 https://purl.org/becyt/ford/1 |
| Sumario: | In this work it was sought to explore the versatility of germinal spin–spin coupling constants, ²JxySSCCs, as probes for stereochemical studies. A set of compounds, where their experimental ²JxySSCCs through the X–C–Y molecular fragment are predicted to be sensitive to hyperconjugative interactions involving either bonding or antibonding orbitals containing the C carbon atom (‘coupling pathway’), were analyzed. SSCC calculations were performed for some selected examples using the second order polarization propagator approximation (SOPPA) method or within the DFT-B3LYP framework. Hyperconjugative interactions were calculated within the Natural Bond Orbital (NBO) approach. Results are condensed in two qualitative rules: Rule Iм—hyperconjugative interactions transferring charge into the coupling pathway yield a positive increase to the Fermi contact (FC), contribution to ²Kxy reduced spin–spin coupling constants (RSSCC), and Rule IIм—hyperconjugative interactions transferring charge from the coupling pathway yield a negative increase to the FC contribution to ²Kxy RSSCC. |
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