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Protonenresonanzspektren von aromatischen N‐Oxiden Berechnung der chemischen Verschiebungen, verursacht durch die Feldeffekte der NO‐gruppe
Author(s) -
Hamm P.,
Philipsborn W. V.
Publication year - 1971
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19710540803
Subject(s) - chemistry , electromagnetic shielding , dipole , protonation , chemical shift , crystallography , oxide , bond length , computational chemistry , stereochemistry , organic chemistry , crystal structure , ion , electrical engineering , engineering
The proton NMR. spectra of a series of aromatic amines, their N‐oxides and the corresponding protonated species are analysed. The results for different protons are expressed in terms of differential chemical shifts of the N‐oxide with respect to the corresponding amine or to the hydrocarbon. These data are compared with calculated shielding values obtained according to the theories of McConnell & Buckingham using published data for the magnetic susceptibilities and electric dipoles of the functional groups. The major part of the shielding by the N‐oxide group originates from the electric dipole. If one considers resonance structures for the aromatic N‐oxides the single bond structure and the double bond structure for the NO bond are of approximately equal importance.