title: Lanthanide Structures, Coordination, and Extraction Investigations of a 1,3-Bis(diethyl amide)-Substituted Calix[4]arene Ligand.
abstract: The synthesis and structure determinations of lanthanum, samarium, ytterbium, and lutetium complexes of 5,11,17,23-tetra-tert-butyl-25,27-bis((diethylcarbamoyl)methoxy)-26,28-dihydroxycalix[4]arene (L) are described. The four structures display similar characteristics with the trivalent lanthanide cation being encapsulated in an eight-coordinate oxygen environment, consisting of six oxygens from the calixarene, a water molecule, and unidentate picrate for lanthanum [La(L-2H)(picrate)(H(2)O)]; and bidentate chelating picrate for the other lanthanides [Ln(L-2H)(picrate)]Ln = Sm, Yb, Lu. Under optimised experimental conditions solvent extraction investigations showed the calix[4]arene ligand L exhibited generally very high percentage extractabilities of lanthanide cations into dichloromethane, presumably on account of the ligand's unique lower rim oxygen containing coordination sphere and its lipophilic exterior.
authors.affiliation: Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QR, U.K., Department of Chemistry, University of Reading, Whiteknights, Reading RG6 2AD, U.K., and Analytical Chemistry Branch, AWE plc, Aldermaston, Reading RG7 4PR, U.K.
authors.forename: Paul D.
authors.initials: PD
authors.lastname: Beer
authors.forename: Michael G. B.
authors.initials: MG
authors.lastname: Drew
authors.forename: Mark
authors.initials: M
authors.lastname: Kan
authors.forename: Philip B.
authors.initials: PB
authors.lastname: Leeson
authors.forename: Mark I.
authors.initials: MI
authors.lastname: Ogden
authors.forename: Gareth
authors.initials: G
authors.lastname: Williams