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Magnetization transfer NMR study of nitrogen inversion in 2,2‐dimethylaziridine
Author(s) -
Johnston Eric R.
Publication year - 1995
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.1260330808
Subject(s) - chemistry , magnetization transfer , magnetization , autocatalysis , nuclear magnetic resonance spectroscopy , spectroscopy , nitrogen , analytical chemistry (journal) , nuclear magnetic resonance , inversion (geology) , nitrogen inversion , catalysis , stereochemistry , organic chemistry , magnetic field , magnetic resonance imaging , medicine , paleontology , physics , quantum mechanics , structural basin , biology , radiology
The slow inversion at pyramidal nitrogen in 2,2‐dimethylaziridine was investigated by NMR spectroscopy at 304 K using one‐dimensional spin locking methods and two‐dimensional exchange spectroscopy. The activation free energy was found to be 17.5 kcal mol −1 (73.2 kJ mol −1 ) at this temperature. This value represents a lower limit for the unimolecular inversion barrier height as autocatalytic and water‐catalyzed inversion pathways can in principle also contribute to the observed rate. The spin locking experiments described employ non‐selective pulses and are particularly useful for the quantitative study of slow chemical exchange between nuclei of similar resonance frequency where selective magnetization transfer experiments are difficult or impossible.