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Investigations of intramolecular hydrogen bonding in three types of Schiff bases by 2 H and 3 H NMR isotope effects
Author(s) -
Schilf Wojciech,
Bloxsidge James P.,
Jones John R.,
Lu ShuiYu
Publication year - 2004
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.1375
Subject(s) - chemistry , deuterium , intramolecular force , kinetic isotope effect , deuterium nmr , hydrogen bond , tautomer , methylamine , tritium , hydrogen , proton nmr , nuclear magnetic resonance spectroscopy , photochemistry , computational chemistry , organic chemistry , molecule , physics , quantum mechanics , nuclear physics
Hydrogen bonding within the structures of three Schiff bases ( 1 – 3 ), obtained by condensation of 4‐methoxy‐, 5‐methoxy‐ and 4,6‐dimethoxysalicylaldehyde with methylamine, was investigated by measuring deuterium and tritium NMR isotope effects. The primary deuterium and tritium isotope effects (δ XH −δ XD/T ) and secondary one‐bond nitrogen deuterium effect appear to be very useful parameters for defining the character of intramolecular hydrogen bonds. The tritium isotope effects were also determined for nitrogen–hydrogen one‐bond coupling constants for both 4‐methoxy and 4,6‐dimethoxy derivatives. These parameters are seen to be highly sensitive to hydrogen bond characteristics and can be used to distinguish localized and tautomeric hydrogen bonds. Copyright © 2004 John Wiley & Sons, Ltd.