Artículo
Understanding proton magnetic shielding in the benzene molecule
Fecha de publicación:
12/2004
Editorial:
Elsevier Science
Revista:
Chemical Physics Letters
ISSN:
0009-2614
Idioma:
Inglés
Tipo de recurso:
Artículo publicado
Clasificación temática:
Resumen
According to the ring current model quoted in textbooks of nuclear magnetic resonance spectroscopy, the downfield chemical shifts of hydrogen nuclei in aromatic molecules is due to intense delocalized currents induced in the π-electron cloud by a magnetic field at right angles to the molecular plane. By using the Biot-Savart law, it was found that the delocalized ring currents deshield the out-of-plane component of proton shielding tensor via an essentially local mechanism taking place in the close vicinity of protons. The π ring currents over distant carbons shield the protons. π and σ electrons deshield benzene protons via different mechanisms clearly observed in plots of the shielding density function defined in the text. These results provide a novel interpretation of the phenomenology and suggest that the familiar model for interpreting chemical shifts of aromatics should be revised. © 2004 Published by Elsevier B.V.
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Articulos(IFIBA)
Articulos de INST.DE FISICA DE BUENOS AIRES
Articulos de INST.DE FISICA DE BUENOS AIRES
Citación
Ferraro, Marta Beatriz; Lazzeretti, Paolo; Viglione, R.G.; Zanasi, R.; Understanding proton magnetic shielding in the benzene molecule; Elsevier Science; Chemical Physics Letters; 390; 1-3; 12-2004; 268-271
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