title: An imine-based molecular cage with distinct binding sites for small and large alkali metal cations.
abstract: The synthesis of a cylindrical, imine-based cage composed of two trimeric metallamacrocycles is described. The cage acts as a heterotopic receptor for alkali metal cations. The small cations Li(+), Na(+), and K(+) bind to the outside of the cage with good selectivity for Li(+), whereas the larger cations Rb(+) and Cs(+) are bound inside the cage to form unusual π complexes with a good selectivity for Cs(+). Negative heterotopic cooperativity between the two binding sites is observed. The complexation of Cs(+) is associated with a color change, which enables the cage to be used as a specific sensor for Cs(+).
authors.affiliation: Institut des Sciences et Ingénierie Chimiques, École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland.
authors.forename: Clément
authors.initials: C
authors.lastname: Schouwey
authors.forename: Rosario
authors.initials: R
authors.lastname: Scopelliti
authors.forename: Kay
authors.initials: K
authors.lastname: Severin
mesh_terms: D000468:Alkalies / Q000737:chemistry*; D001665:Binding Sites; D002412:Cations / Q000737:chemistry; D007097:Imines / Q000737:chemistry*; D008672:Metals, Alkali / Q000737:chemistry*
chemical_list: D000468:Alkalies; D002412:Cations; D007097:Imines; D008672:Metals, Alkali