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A dynamic nuclear magnetic resonance study of nitrogen inversion in N , N '‐dimethylimidazolidine
Author(s) -
Anet Frank A. L.,
Yavari Issa
Publication year - 1979
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270120607
Subject(s) - nitrogen , nitrogen inversion , spectral line , inversion (geology) , chemistry , nmr spectra database , nuclear magnetic resonance , analytical chemistry (journal) , physics , organic chemistry , paleontology , structural basin , astronomy , biology
The 251 MHz 1 H and the natural‐abundance 63.1 MHz 13 C NMR spectra of N , N '‐dimethylimidazolidine have been measured from −50 to −170°C. Below about −140°C. nitrogen inversion in the compound becomes slow on the NMR time scale and both the 1 H and the 13 C spectra indicate that it exists in solution as a mixture of cis and trans conformations having nearly the same energies. The free‐energy barrier (ΔG ≠ ) for nitrogen inversion in N , N '‐dimethylimidazolidine is 6.4 kcal mol −1 , a value which is 1.5 kcal mol −1 lower than that for N ‐methylpyrrolidine.