LANTHANIDE STRUCTURES, COORDINATION, AND EXTRACTION INVESTIGATIONS OFA 1,3-BIS(DIETHYL AMIDE)-SUBSTITUTED CALIX[4]ARENE LIGAND

The synthesis and structure determinations of lanthanum, samarium, ytt erbium, and lutetium complexes of is((diethylcarbamoyl)methoxy)-26,28- dihydroxycalix [4] arene (L) are described. The four structures displa y similar characteristics with the trivalent lanthanide cation being e ncapsulated in an eight-coordinate oxygen environment, consisting of s ix oxygens from the calixarene, a water molecule, and unidentate picra te for lanthanum [La(L-2H)(picrate)(H2O)]; and bidentate chelating pic rate for the other lanthanides [Ln(L-2H)(picrate)]Ln = Sm, Yb, Lu. Und er optimised experimental conditions solvent extraction investigations showed the calix[4]arene ligand L exhibited generally very high perce ntage extractabilities of lanthanide cations into dichloromethane, pre sumably on account of the ligand's unique lower rim oxygen containing coordination sphere and its lipophilic exterior.