An NMR investigation of the existence of halide and carboxylate co-solute effects on the rotational barrier about the C-N bonds in urea and thiourea

作者：Gerken James B^*; Ross Scott

来源：Journal of Physical Organic Chemistry, 2010, 23(9): 806-809.

DOI：10.1002/poc.1665

• halide
• hydrogen bond
• rotational barrier
• thiourea
• urea

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 N-H 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 Delta G double dagger 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.

• 出版日期2010-9