ISSN:
1572-8927
Keywords:
Cesium-133 NMR
;
cryptates
;
alkali complexes
;
stability constants
;
nonaqueous solvents
Source:
Springer Online Journal Archives 1860-2000
Topics:
Chemistry and Pharmacology
Notes:
Abstract Cesium complexes with four diazapolyoxamacrobicyclic ligands ([2]-cryptands), C211, C221, C222, and C222B, were investigated in pyridine, acetone, propylene carbonate, N,N-dimethylformamide, acetonitrile, and dimethyl sulfoxide solutions by cesium-133 NMR. The relative stabilities of the complexes are in the order Cs+·C221≥Cs+·C222〉Cs+·C222B≫Cs+·C211. The formation constants are strongly influenced by the solvating abilities of the solvents. The NMR data and stereochemical considerations indicate that in the C222−Cs+ system there is an equilibrium between “exclusive” and “inclusive” conformations of the complex. The other three ligands must form only the “exclusive” complex.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00650453
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