Uranyl carboxyphosphonates that incorporate Cd(II)

The hydrothermal treatment of UO3, Cd(CH3CO2)2·2H2O, and triethyl phosphonoacetate results in the formation of Cd2[(UO2)6(PO3CH2CO2)3O3(OH)(H2O)2]·16H2O (CdUPAA-1), [Cd3(UO2)6(PO3CH2CO2)6(H2O)13]·6H2O (CdUPAA-2), and Cd(H2O)2[(UO2)(PO3CH2CO2)(H2O)]2 (CdUPAA-3). CdUPAA-1 adopts a cubic three-dimensional structure constructed from planar uranyl oxide clusters containing both UO7 pentagonal bipyramids and UO8 hexagonal bipyramids that are linked by Cd(II) cations and phosphonoacetate to yield large cavities approximately 16 Å across that are filled with disordered water molecules. CdUPAA-2 forms a rhombohedral three-dimensional channel structure that is assembled from UO7 pentagonal bipyramids that are bridged by phosphonoacetate. CdUPAA-3 is layered with the hydrated Cd(II) cations incorporated directly into the layers linking one-dimensional uranyl phosphonate substructures together. In this structure, there are complex networks of hydrogen bonds that exist within the sheets, and also stitch the sheets together.

A view of part of the cubic structure of Cd2[(UO2)6(PO3CH2CO2)3O3(OH)(H2O)2]·16H2O.Figure optionsDownload as PowerPoint slideHighlights
► High symmetry uranyl compounds.
► Three-dimensional structures.
► Porous materials.
► Heterobimetallic compounds.