title: 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.
abstract: 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.
authors.affiliation: Faculté des Sciences et Techniques, Méthodologie RMN, UMR CNRS-UHP 7036; CRM2, Nancy-Université, Vandoeuvre-lés Nancy Cedex, France.
authors.forename: Diana
authors.initials: D
authors.lastname: Cuc
authors.forename: Sabine
authors.initials: S
authors.lastname: Bouguet-Bonnet
authors.forename: Nicole
authors.initials: N
authors.lastname: Morel-Desrosiers
authors.forename: Jean-Pierre
authors.initials: JP
authors.lastname: Morel
authors.forename: Pierre
authors.initials: P
authors.lastname: Mutzenhardt
authors.forename: Daniel
authors.initials: D
authors.lastname: Canet
mesh_terms: 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
chemical_list: D002250:Carbon Radioisotopes; D002412:Cations; D008670:Metals; D010636:Phenols; C511968:p-sulfonatocalix(4)arene; D014867:Water; D047250:Calixarenes; D002586:Cesium; D013793:Thallium