Location of a metallic cation complexed in a calixarene cavity as determined by calixarene 13C spin relaxation. application to cesium and thallium complexed by p-sulfonatocalix[4]arene in water.
This study deals with the exact location of the monovalent metal cations Cs(+) and Tl(+) which are complexed by the p-sulfonatocalix[4]arene in water. This determination rests on the measurements of longitudinal relaxation times of carbon-13 not directly bonded to protons. The difference between the relaxation times of the free calixarene and of the complex definitely demonstrates that the monovalent metal cation is well inside the calixarene cavity. These features are in fact enhanced by the presence of paramagnetic species which act in a different way in the complexed form. Experimental results also show without any ambiguity that the calixarene cavity is essentially hydrophobic. Finally, it is observed that thallium is more mobile than cesium within the calixarene cavity.
Cuc
Diana
D
Faculté des Sciences et Techniques, Méthodologie RMN, UMR CNRS-UHP 7036; CRM2, Nancy-Université, Vandoeuvre-lés Nancy Cedex, France.
Bouguet-Bonnet
Sabine
S
Morel-Desrosiers
Nicole
N
Morel
Jean-Pierre
JP
Mutzenhardt
Pierre
P
Canet
Daniel
D
D016880:Anisotropy; D047250:Calixarenes / Q000737:chemistry*; D002250:Carbon Radioisotopes; D002412:Cations / Q000737:chemistry*; D002586:Cesium / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D007474:Ion Exchange; D009682:Magnetic Resonance Spectroscopy; D008670:Metals / Q000737:chemistry*; D010636:Phenols / Q000737:chemistry*; D013793:Thallium / Q000737:chemistry*; D014867:Water
D002250:Carbon Radioisotopes; D002412:Cations; D008670:Metals; D010636:Phenols; C511968:p-sulfonatocalix(4)arene; D014867:Water; D047250:Calixarenes; D002586:Cesium; D013793:Thallium