Abstract
Ion-solvent interactions of Na+ and Br− in binary aqueous mixtures of formamide,N-methylformamide (NMF), andN,N-dimethylformamide (DMF) are studied by use of23Na and81Br magnetic relaxation times, extrapolated to zero salt concentration. The relaxation times, which are controlled by quadrupolar interaction, have been measured over the complete mixture range and are compared with a simplified theoretical formula. It turned out that the23Na+ relaxation in H2O-formamide and H2O-NMF mixtures is in excellent agreement with theoretical predictions, implying nonpreferential solvation of Na+ in these systems. Small deviations of experimental from theoretical results in H2O+DMF possibly indicate weak selective hydration of the cation. In the case of the anionic nuclei81Br−, deviations from the theoretical curve occur which are to be expected, especially for systems where hydrophobic effects play a role. On the other hand, it is demonstrated that these deviations can easily be explained within the electrostatic theory by differences in structural details of the anionic solvation sphere in the mixtures compared to the pure solvents.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
H. G. Hertz,Ber. Bunsenges. Phys. Chem. 77, 531 (1973).
H. G. Hertz,Ber. Bunsenges. Phys. Chem. 77, 688 (1973).
H. G. Hertz, M. Holz, R. Klute, G. Stalidis, and H. Versmold,Ber. Bunsenges. Phys. Chem. 78, 24 (1974).
H. G. Hertz, M. Holz, G. Keller, H. Versmold, and C. Yoon,Ber. Bunsenges. Phys. Chem. 78, 493 (1974).
C. A. Melendres and H. G. Hertz,J. Chem. Phys. 61, 4156 (1974).
H. Weingärtner and H. G. Hertz,Ber. Bunsenges. Phys. Chem. 81, 1204 (1977).
M. Holz, H. Weingärtner, and H. G. Hertz,J. Chem. Soc. Faraday Trans. 1 73, 71 (1977).
M. Holz,J. Chem. Soc. Faraday Trans. 1 74, 644 (1978).
R. A. Craig and R. E. Richards,Trans. Faraday Soc. 59, 1559 (1967).
A. I. Mishustin and Yu. M. Kessler,J. Solution Chem. 4, 779 (1975).
H. Weingärtner, M. Holz, and H. G. Hertz,J. Solution Chem. 7, 689 (1978).
H. G. hertz and M. Holz,J. Phys. Chem. 78, 1002 (1974).
G. Engel and H. G. Hertz,Ber. Bunsenges. Phys. Chem. 72, 808 (1968).
G. Ebert and J. Wendorff,Ber. Bunsenges. Phys. Chem. 74, 1071 (1970).
H. G. Hertz, R. Tutsch, and H. Versmold,Ber. Bunsenges. Phys. Chem. 75, 1177 (1971).
M. Contreras and H. G. Hertz,Faraday Discuss. Chem. Soc. 64, 33 (1977).
M. Contreras and H. G. Hertz,J. Solution Chem. 7, 99 (1978).
H. G. Hertz,Ber. Bunsenges. Phys. Chem. 74, 666 (1970).
H. G. Hertz,Ber. Bunsenges. Phys. Chem. 75, 572 (1971).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Holz, M., Weingärtner, H. & Hertz, H.G. Nuclear magnetic relaxation and ionic solvation of23Na+ and81Br− in aqueous mixtures of simple amides. J Solution Chem 7, 705–720 (1978). https://doi.org/10.1007/BF00652020
Received:
Revised:
Issue Date:
DOI: https://doi.org/10.1007/BF00652020