Andrzej Kolinski Research Group

Coarse-grained protein modeling

Modeling Software & Servers

Biomolecules — dynamics & interactions

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Assessment of Solvent-Induced Nitrogen Shielding Variations of Triazole Systems

Source:

Journal of Magnetic Resonance, Series A, 112:66 - 71, 1995

Abstract

High-precision 14N \{NMR\} shieldings are reported for all of the possible N-methyl triazoles in a variety of solvents. A large difference is observed in the effects of solvent on the shieldings of the pyrrole-type and pyridine-type nitrogen atoms in such systems. This difference largely arises from solvent-to-solute hydrogen-bonding effects for the latter type of nitrogen atom. For these two types of nitrogen atoms in triazoles, solvent polarity effects induce changes in the shieldings in opposite directions: this is corroborated by shielding calculations using the solvaton model. Solvent-to-solute hydrogen-bonding effects are larger than those due to solvent polarity and permit the assessment of the basicities of nonequivalent nitrogenous sites; these appear to parallel the analogous basicities with respect to protonation.