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An ab initio study of solvent polarity and hydrogen bonding effects on the nitrogen NMR shieldings of N,N-dimethylacetamidine

✍ Scribed by Marlon N. Manalo; Angel C. de Dios

Publisher
John Wiley and Sons
Year
2002
Tongue
English
Weight
107 KB
Volume
40
Category
Article
ISSN
0749-1581

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✦ Synopsis

Abstract

Density functional theory combined with the polarizable continuum model (PCM) and continuous set of gauge transformations method is applied to investigate the effects of solvent polarity on the nitrogen NMR shieldings of N, N‐dimethylacetamidine. Hydrogen bonding effects on shielding are likewise calculated using a supermolecule approach, where the imino group of the solute is hydrogen bonded with solvent. Theoretical results are compared with published experimental data. The PCM shielding calculations utilizing PCM‐optimized solute geometries yield results comparable to those obtained with the supermolecule approach. Geometry optimization of the solute appears to be more important in PCM shielding calculations than in the supermolecule approach. The large solvent shifts observed in water can only be reproduced when the NΒ·H distance used in the calculation indicates full proton transfer from water to the imino nitrogen of the solute. Copyright Β© 2002 John Wiley & Sons, Ltd.

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