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An NMR investigation of the existence of halide and carboxylate co‐solute effects on the rotational barrier about the CN bonds in urea and thiourea
Author(s) -
Gerken James B.,
Ross Scott
Publication year - 2010
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.1665
Subject(s) - chemistry , thiourea , hydrogen bond , acetonitrile , halide , iodide , carboxylate , proton nmr , inorganic chemistry , urea , carbon 13 nmr , medicinal chemistry , molecule , organic chemistry
Rotational barriers of the NH 2 group in thiourea and benzylurea in solution become slightly larger in the presence of anionic hydrogen‐bond acceptors. The interactions between the NH bond and different anions were investigated in acetonitrile solution using 1 H{ 14 N} variable‐temperature NMR. Line‐shape analyses of the spectra show a weakly anion‐dependent increase in Δ G ‡ of rotation, with benzoate having the strongest effect and iodide the weakest. Hydrogen‐bonding acidities of benzylurea and thiourea were also measured on the Abraham solute hydrogen‐bond acidity scale by proton NMR. Copyright © 2010 John Wiley & Sons, Ltd.