Andrzej Kolinski Research Group

Coarse-grained protein modeling

Modeling Software & Servers

Biomolecules — dynamics & interactions

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A NMR study of solute-solvent interactions as a function of the nitrogen shielding of pyridine N-oxide

Source:

Journal of Magnetic Resonance, 83:351 - 357, 1989

Abstract

The range of solvent effects on the nitrogen shielding of pyridine N-oxide is found to be comparable to that of pyridine, amounting to about 30 ppm. The largest contribution to this range arises from hydrogen bonding from the solvents to the oxygen atom of pyridine N-oxide. For the first time it is demonstrated that hydrogen bonding to a neighboring atom can have a comparable effect on nitrogen shielding as would direct hydrogen bonding to the nitrogen atom. Medium polarity effects on the nitrogen shielding of pyridine and its N-oxide are of the same sign and order of magnitude. This is corroborated by INDO/S-SOS shielding calculations using the solvaton model. These medium polarity effects amount to a nitrogen shielding variation not exceeding 6 ppm while those due to hydrogen bonding exceed 20 ppm.