Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study
In order to obtain a deeper insight into the title effect, several compounds with an F atom very close to a C-H of a nearby functional group were synthesized and the relevant couplings measured. The most conspicuous case was that of 8-fluoro-2-hydroxynaphthalene-l-carbaldehyde where a close proximit...
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00049425_v40_n12_p1923_Rae |
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todo:paper_00049425_v40_n12_p1923_Rae2023-10-03T14:03:09Z Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study Rae, I.D. Staffa, A. Diz, A.C. Giribet, C.G. de Azúa, M.C.R. Contreras, R.H. In order to obtain a deeper insight into the title effect, several compounds with an F atom very close to a C-H of a nearby functional group were synthesized and the relevant couplings measured. The most conspicuous case was that of 8-fluoro-2-hydroxynaphthalene-l-carbaldehyde where a close proximity between the F and H atoms is the result of fluorine-oxygen repulsion and the formation of an intramolecular hydrogen bond between the hydroxyl and carbonyl groups. The experimental four-bond J(F, CHO) coupling is 26·2 Hz. A compound very similar to this one, but without the OH group, was chosen on which to perform a polarization propagator analysis of the through-space (ts) coupling pathways, at the rpa-indo level. The expression for the ts coupling in terms of the projected polarization propagator and perturbators was numerically analysed. It is found that this coupling is completely dominated by a ts component of the Fermi contact (fc) term, the main features of which are: (i) It decays exponentially with the F-H distance; (ii) Its main contribution comes from an electron excitation involving the F lone-pair, the C-H bond of the CHO moiety and its corresponding antibonding orbital; (iii) The π-type lone-pair does not contribute to the ts coupling pathway of the FC term. © 1987 ASEG. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00049425_v40_n12_p1923_Rae |
| institution |
Universidad de Buenos Aires |
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I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| description |
In order to obtain a deeper insight into the title effect, several compounds with an F atom very close to a C-H of a nearby functional group were synthesized and the relevant couplings measured. The most conspicuous case was that of 8-fluoro-2-hydroxynaphthalene-l-carbaldehyde where a close proximity between the F and H atoms is the result of fluorine-oxygen repulsion and the formation of an intramolecular hydrogen bond between the hydroxyl and carbonyl groups. The experimental four-bond J(F, CHO) coupling is 26·2 Hz. A compound very similar to this one, but without the OH group, was chosen on which to perform a polarization propagator analysis of the through-space (ts) coupling pathways, at the rpa-indo level. The expression for the ts coupling in terms of the projected polarization propagator and perturbators was numerically analysed. It is found that this coupling is completely dominated by a ts component of the Fermi contact (fc) term, the main features of which are: (i) It decays exponentially with the F-H distance; (ii) Its main contribution comes from an electron excitation involving the F lone-pair, the C-H bond of the CHO moiety and its corresponding antibonding orbital; (iii) The π-type lone-pair does not contribute to the ts coupling pathway of the FC term. © 1987 ASEG. |
| format |
JOUR |
| author |
Rae, I.D. Staffa, A. Diz, A.C. Giribet, C.G. de Azúa, M.C.R. Contreras, R.H. |
| spellingShingle |
Rae, I.D. Staffa, A. Diz, A.C. Giribet, C.G. de Azúa, M.C.R. Contreras, R.H. Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study |
| author_facet |
Rae, I.D. Staffa, A. Diz, A.C. Giribet, C.G. de Azúa, M.C.R. Contreras, R.H. |
| author_sort |
Rae, I.D. |
| title |
Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study |
| title_short |
Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study |
| title_full |
Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study |
| title_fullStr |
Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study |
| title_full_unstemmed |
Through-space transmission of 19F-13C coupling via an intermediate bond. An experimental and theoretical study |
| title_sort |
through-space transmission of 19f-13c coupling via an intermediate bond. an experimental and theoretical study |
| url |
http://hdl.handle.net/20.500.12110/paper_00049425_v40_n12_p1923_Rae |
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