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Abstract:

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.

Registro:

Documento: Artículo
Título:Understanding proton magnetic shielding in the benzene molecule
Autor:Ferraro, M.B.; Lazzeretti, P.; Viglione, R.G.; Zanasi, R.
Filiación:Departamento de Física, Fac. de Ciencias Exactas Y Naturales, Pab. I, (1428) Buenos Aires, Argentina
Dipartimento di Chimica, Dell'Univ. Studi Modena Reggio E., Via Campi 183, 41100 Modena, Italy
Dipartimento di Chimica, Dell'Univ. degli Studi di Salerno, via S. Allende, 84081 Baronissi (SA), Italy
Palabras clave:aromatic compound; benzene; carbon; proton; article; density functional theory; electric current; electron; model; molecular mechanics; molecule; phenomenology; proton nuclear magnetic resonance
Año:2004
Volumen:390
Número:1-3
Página de inicio:268
Página de fin:271
DOI: http://dx.doi.org/10.1016/j.cplett.2004.04.022
Título revista:Chemical Physics Letters
Título revista abreviado:Chem. Phys. Lett.
ISSN:00092614
CODEN:CHPLB
CAS:benzene, 71-43-2; carbon, 7440-44-0; proton, 12408-02-5, 12586-59-3
Registro:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00092614_v390_n1-3_p268_Ferraro

Referencias:

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Citas:

---------- APA ----------
Ferraro, M.B., Lazzeretti, P., Viglione, R.G. & Zanasi, R. (2004) . Understanding proton magnetic shielding in the benzene molecule. Chemical Physics Letters, 390(1-3), 268-271.
http://dx.doi.org/10.1016/j.cplett.2004.04.022
---------- CHICAGO ----------
Ferraro, M.B., Lazzeretti, P., Viglione, R.G., Zanasi, R. "Understanding proton magnetic shielding in the benzene molecule" . Chemical Physics Letters 390, no. 1-3 (2004) : 268-271.
http://dx.doi.org/10.1016/j.cplett.2004.04.022
---------- MLA ----------
Ferraro, M.B., Lazzeretti, P., Viglione, R.G., Zanasi, R. "Understanding proton magnetic shielding in the benzene molecule" . Chemical Physics Letters, vol. 390, no. 1-3, 2004, pp. 268-271.
http://dx.doi.org/10.1016/j.cplett.2004.04.022
---------- VANCOUVER ----------
Ferraro, M.B., Lazzeretti, P., Viglione, R.G., Zanasi, R. Understanding proton magnetic shielding in the benzene molecule. Chem. Phys. Lett. 2004;390(1-3):268-271.
http://dx.doi.org/10.1016/j.cplett.2004.04.022