title: Calixarenes as scaffolds: introduction of tridentate rare earth metal binding units into calix[4]arene.
abstract: The reactions of various derivatives of chelidamic acid (4-hydroxypyridine-2,6-dicarboxylic acid) with p-tert-butylcalix[4]arene have produced several new mono- and difunctionalized derivatives of the calixarene in which tridentate functional groups suitable for the binding of rare earth metal cations have been incorporated. Single-crystal X-ray structure determinations have been performed on two difunctionalized calixarenes found to adopt different "cone" and "1,2-alternate" conformations, as well as on a complex of europium(III) with the phenoxide form of a monofunctionalized ligand, this structure confirming that charge factors are dominant in determining the site of lanthanide metal binding in these ligands.
authors.affiliation: Special Research Centre for Advanced Mineral and Materials Processing and Department of Chemistry, University of Western Australia, Nedlands WA 6907, Australia.
authors.forename: P
authors.initials: P
authors.lastname: Froidevaux
authors.forename: J M
authors.initials: JM
authors.lastname: Harrowfield
authors.forename: A N
authors.initials: AN
authors.lastname: Sobolev