Cesium-133 nuclear magnetic resonance study of complexation by cryptand C222 in various solvents: evidence for exclusive and inclusive complexes

Journal Article · Wed Sep 28 00:00:00 EDT 1977 · J. Am. Chem. Soc.; (United States)

DOI:https://doi.org/10.1021/ja00462a011· OSTI ID:7208683

Mei, E; Popov, A I; Dye, J L

The chemical shift of the /sup 133/Cs resonance was studied as a function of the mole ratio of cryptand C222 to Cs/sup +/ at various temperatures in six solvents, pyridine, acetone, propylene carbonate, N,N-dimethylformamide, acetonitrile, and dimethyl sulfoxide. The variation of the chemical shift with the mole ratio was used to determine the apparent complexation constants at temperatures high enough to yield a single, exchange-narrowed line. At lower temperatures, complete line-shape analysis was used to determine apparent exchange rates. The limiting chemical shift at high C222/Cs/sup +/ mole ratios was found to be strongly dependent upon both solvent and temperature but converged to a solvent-independent value of -245 +- 5 ppM (downfield) at low temperatures. The behavior of the chemical shift and the variation of the line shape and apparent activation energy with temperature suggest the presence of two types of 1 : 1 complexes in solution, an exclusive complex in which the ion may interact with the solvent, and an inclusive complex which has a solvent-independent chemical shift. The temperature dependence of both the thermodynamic and the rate parameters is consistent with this model.

• Research Organization: Michigan State Univ., East Lansing
• OSTI ID: 7208683
• Journal Information: J. Am. Chem. Soc.; (United States), Journal Name: J. Am. Chem. Soc.; (United States) Vol. 99:20; ISSN JACSA
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
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CARBONIC ACID ESTERS
CESIUM COMPLEXES
COMPLEXES
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ORGANIC NITROGEN COMPOUNDS
ORGANIC SOLVENTS
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TEMPERATURE DEPENDENCE