ISSN:
0749-1581
Schlagwort(e):
Second-order magnetic properties
;
Five- and six-membered nitrogen heterocycles
;
Calculated NMR shifts
;
Chemistry
;
Analytical Chemistry and Spectroscopy
Quelle:
Wiley InterScience Backfile Collection 1832-2000
Thema:
Chemie und Pharmazie
Notizen:
Second-order magnetic properties, i.e. magnetic susceptibility and chemical shift tensors, of some five- and six- membered heterocycles containing nitrogen were calculated by means of the IGLO method. The molecules studied were the azoles pyrrole, pyrazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, and 1H- and 2H-tetrazole, together with the corresponding N-methyl-substituted compounds, the azines pyridazine, pyrimidine, pyrazine, s-triazine, 1,2,3-triazine, s-tetrazine, pyridine and borazine.Confirming previous investigations, good agreement was found between calculation and experiment. Only the calculated NMR shifts of nitrogen atoms that are involved in N—N multiple bonds are too paramagnetic (deshielded). This effect (probably due to the neglect of electron correlation) is much less pronounced for the partial N—N double bonds in aromatic rings than for genuine N—N multiple bonds studied previously.
Zusätzliches Material:
7 Ill.
Materialart:
Digitale Medien
URL:
http://dx.doi.org/10.1002/mrc.1260260510
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