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Conformational analysis of N,N,N ‐Trimethyl‐(3,3‐dimethylbutyl)ammonium iodide by NMR spectroscopy: a sterically hindered trans ‐standard
Author(s) -
Liu Albert Tianxiang,
Nag Mrinmoy,
Carroll William R.,
Roberts John D.
Publication year - 2013
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.4003
Subject(s) - chemistry , ammonium iodide , conformational isomerism , iodide , steric effects , solubility , nuclear magnetic resonance spectroscopy , substituent , proton nmr , ammonium , organic chemistry , molecule
A predominantly trans ‐1,2‐disubstituted ethane system – N,N,N ‐trimethyl‐(3,3‐dimethylbutyl)ammonium iodide – is of particular interest for conformational analysis, because it contains both an organic and a highly polar substituent, making it soluble and thus applicable to study in a large variety of solvents. The fraction of the trans conformer of this molecule in a wide range of protic and aprotic solvents was determined by the nuclear magnetic resonance proton couplings to be approximately 90%, in contrast to the previously assumed 100%. The consistently strong preference of the trans conformation should establish N,N,N ‐trimethyl‐(3,3‐dimethylbutyl)ammonium iodide as a possibly useful ‘ trans ‐standard’ in conformational analysis, much more so than 1,2‐ditert‐butylethane, which has a poor solubility in many solvents. Copyright © 2013 John Wiley & Sons, Ltd.