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Magnetic properties in terms of localized quantities. VIII —Azines and azoles
Author(s) -
Schindler Michael
Publication year - 1988
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.1260260510
Subject(s) - chemistry , pyridazine , pyrazole , tetrazole , imidazole , triazine , pyrrole , tetrazine , pyridine , borazine , pyrazine , crystallography , computational chemistry , molecule , stereochemistry , medicinal chemistry , organic chemistry , boron nitride
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 1 H ‐ and 2 H ‐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 NN multiple bonds are too paramagnetic (deshielded). This effect (probably due to the neglect of electron correlation) is much less pronounced for the partial NN double bonds in aromatic rings than for genuine NN multiple bonds studied previously.