Aqueous solutions of methylated and ethylated derivatives of urea have been investigated by proton and carbon-13 magnetic resonance technique. The chemical shifts of water protons in solution of alkylureas, relative to that of pure water, are as a measure of the hydrogen-bonding reinforcing or weakening ability of these substances. The dependence of this effect on the concentration and on the temperature has also been studied. The results obtained indicate that different contrasting effects act in these solutions, among then the water structuring effect of the nonpolar surface of the alkylureas and the effect of the volume of the solute.13C chemical shifts of the carbonyl groups of the alkylureas give useful information about the interactions between water and the polar part of the ureas. Carbonyl-water interactions exist but are partially destroyed by increasing concentrations of the solute. © 1977 Plenum Publishing Corporation.
Nuclear magnetic resonance studies of aqueous solutions of alkylureas: Proton and carbon-13 chemical shifts / G., Barone; Castronuovo, Giuseppina; C., Della Volpe; V., Elia. - In: JOURNAL OF SOLUTION CHEMISTRY. - ISSN 0095-9782. - ELETTRONICO. - 6:(1977), pp. 117-127. [10.1007/BF00646733]
Nuclear magnetic resonance studies of aqueous solutions of alkylureas: Proton and carbon-13 chemical shifts
CASTRONUOVO, GIUSEPPINA;
1977
Abstract
Aqueous solutions of methylated and ethylated derivatives of urea have been investigated by proton and carbon-13 magnetic resonance technique. The chemical shifts of water protons in solution of alkylureas, relative to that of pure water, are as a measure of the hydrogen-bonding reinforcing or weakening ability of these substances. The dependence of this effect on the concentration and on the temperature has also been studied. The results obtained indicate that different contrasting effects act in these solutions, among then the water structuring effect of the nonpolar surface of the alkylureas and the effect of the volume of the solute.13C chemical shifts of the carbonyl groups of the alkylureas give useful information about the interactions between water and the polar part of the ureas. Carbonyl-water interactions exist but are partially destroyed by increasing concentrations of the solute. © 1977 Plenum Publishing Corporation.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.