Uranyl Complexes with (Meth)acrylate Anions

Two isostructural series with general formulae [R(H2O)(6)][UO2(CH2CHCOO)(3)](2) (R = Mg, Co, or Ni) and [R(H2O)(6)][UO2{CH2C(CH3)COO}(3)](2)8H(2)O (R = Mg or Zn) have been synthesized and characterized by single-crystal X-ray diffraction and IR spectroscopy. The acrylate and methacrylate series of complexes crystallize in the monoclinic crystal system with the space groups P2(1)/c and P2(1)/n, respectively. The crystal structures of all the studied compounds have similar main structural units, specifically, octahedral aqua complexes [R(H2O)(6)](2+) and tris(carboxylato) complexes [UO2L3](-) (L = acrylate or methacrylate anion). Despite this, there are significant structural differences between the two series that lead to the inclusion of outer-sphere water molecules in the structures of the methacrylate series. The intermolecular interactions in the acrylate series were studied by the method of molecular Voronoi-Dirichlet polyhedra and compared with those in previously studied acetate compounds. The structures of the methacrylate series of complexes demonstrate an important role of interactions in the molecular packing of the complexes.