Uranyl(VI) ion complexes of some organic aminobisphenolate ligands : syntheses, structures and extraction studies

Abstract

This thesis reports the syntheses and characterization of 18 organic aminobisphenolate ligands and 20 new uranyl complexes of the prepared ligands, as well as extraction studies of the uranyl ion from an aqueous phase to a water-immiscible organic solvent phase (dichloromethane) in various chemical environments with these ligands. The 18 aminobisphenolate ligands prepared can be subdivided into three sections that have chemically different functional groups in their "tail" part of the molecule. These groups are aminoalcoholbisphenols, aminoalkylbisphenols and diaminobisphenols. 12 of these ligands are new compounds and one of them, bis(5-tert-butyl-2-hydroxy-3-methylbenzyl)(6-hydroxyhexyl)ammonium chloride monohydrate, proved to be an anion receptor. All the 20 new uranyl complexes prepared formed crystals suitable for single-crystal X-ray analysis and of these crystals 19 structures were solved. The solved structures formed three different kinds of compounds, viz. [UO2(HnLm)2]‧kS (n=l or 2, m=l-17, k=0, 1, 2 or 4, S=solvent molecule), [UO2(HLm)(NO3)]‧kS (m=15 or 16, k=l or 2, S=solvent molecule) and [(UO2)2(H2Ll)2(NO3)2]. 16 complexes are of the form [UO2(HnLm)2]·kS, two are of the form [UO2(HLm)(NO3)]‧kS and one of the compounds has a dinuclear structure [(UO2)2(H2Ll)2(NO3)2]. The ability of all the prepared ligands to extract uranyl ions from an aqueous uranyl nitrate solution to dichloromethane was studied. The aminoalcoholbisphenol and aminoalkylbisphenol ligands proved to be excellent uranyl ion extractors under the conditions studied. In addition, the extraction of uranyl ions was studied in various chemical circumstances with selected ligands. Finally, the behaviour of some of the prepared uranyl complexes in CHCl3 and DMSO solutions was studied by NMR. The results of the above studies are presented in five scientific articles.