Synthesis and crystal structure analysis of uranyl triple acetates

Single crystals of triple acetates NaR[UO2(CH3COO)3]3·6H2O (R=Mg, Co, Ni, Zn), well-known for their use as reagents for sodium determination, were grown from aqueous solutions and their structural and spectroscopic properties were studied. Crystal structures of the mentioned phases are based upon {Na[UO2(CH3COO)3]3}2– clusters and [R(H2O)6]2+ aqua-complexes. The cooling of a single crystal of NaMg[UO2(CH3COO)3]3·6H2O from 300 to 100 K leads to a phase transition from trigonal to monoclinic crystal system. Intermolecular interactions between the structural units and their mutual packing were studied and compared from the point of view of the stereoatomic model of crystal structures based on Voronoi-Dirichlet tessellation. Using this method we compared the crystal structures of the triple acetates with Na[UO2(CH3COO)3] and [R(H2O)6][UO2(CH3COO)3]2 and proposed reasons of triple acetates stability. Infrared and Raman spectra were collected and their bands were assigned

Structural features of uranyl acrylate complexes with s-, p-, and d-monovalent metals

A series of uranyl acrylate complexes with s-, p-, and d- monovalent cations (Li, Na, Tl, and Ag) was synthesized and characterized by single crystal X-ray diffraction and IR spectroscopy. We demonstrated that the nature of the monovalent cation strongly affects the composition and crystal structure of an uranyl acrylate. Li[UO2(acr)3]·H2O (1, acr=CH2CHCOO−) crystallizes in the tetragonal crystal system and is built of chains which are connected through hydrogen bonding. The presence of an acrylic acid dimer in the reaction results in the monoclinic compound Na3[UO2(acr)3][UO2(acr)2.5(CH2CHCOOCH2CH2COO)0.5]2·5H2O (2), in which the acrylic dimer shares a position with both the acrylate anion and a water molecule. Tl[UO2(acr)3] (3) exists as two polymorphs and crystallizes in either P-1 (3a) or P213 (3b) space groups. The polymorphs differ in the dimensionality, 2D for 3a and 3D for 3b, and density. Ag2[UO2(NO3)2(acr)2]·2Hacr (4) is the first example of the Ag atom coordination to the acrylate anion through the vinyl group. In 4, the Ag–C bonds enhances the connectivity of the trinuclear [Ag2UO2(acr)2(Hacr)2(NO3)2] clusters into a layered coordination polymer. A detailed structural study of the obtained compounds was performed using Voronoi-Dirichlet tessellation

Synthesis and X‑ray Crystallography of [Mg(H₂O)₆][AnO₂(C₂H₅COO)₃]₂ (An = U, Np, or Pu)

Synthesis and X-ray crystallography of single crystals of [Mg­(H₂O)₆]­[AnO₂(C₂H₅COO)₃]₂, where An = U (<b>I</b>), Np (<b>II</b>), or Pu (<b>III</b>), are reported. Compounds <b>I</b>–<b>III</b> are isostructural and crystallize in the trigonal crystal system. The structures of <b>I</b>–<b>III</b> are built of hydrated magnesium cations [Mg­(H₂O)₆]²⁺ and mononuclear [AnO₂(C₂H₅COO)₃]⁻ complexes, which belong to the AB⁰¹₃ crystallochemical group of uranyl complexes (A = AnO₂²⁺, B⁰¹ = C₂H₅COO^–). Peculiarities of intermolecular interactions in the structures of [Mg­(H₂O)₆]­[UO₂(L)₃]₂ complexes depending on the carboxylate ion L (acetate, propionate, or <i>n</i>-butyrate) are investigated using the method of molecular Voronoi–Dirichlet polyhedra. Actinide contraction in the series of U­(VI)–Np­(VI)–Pu­(VI) in compounds <b>I</b>–<b>III</b> is reflected in a decrease in the mean AnO bond lengths and in the volume and sphericity degree of Voronoi–Dirichlet polyhedra of An atoms

Electronic Structure of Cesium Butyratouranylate(VI) as Derived from DFT-assisted Powder X‑ray Diffraction Data

Investigation of chemical bonding and electronic structure of coordination polymers that do not form high-quality single crystals requires special techniques. Here, we report the molecular and electronic structure of the first cesium butyratouranylate, Cs­[UO₂(<i>n</i>-C₃H₇COO)₃]­[UO₂(<i>n</i>-C₃H₇COO)­(OH)­(H₂O)], as obtained from DFT-assisted powder X-ray diffraction data because of the low quality of crystalline sample. The topological analysis of the charge distribution within the quantum theory of atoms-in-molecules (QTAIM) space partitioning and the distribution of electron localization function (ELF) is reported. The constancy of atomic domain of the uranium­(VI) atom at different coordination numbers (7 and 8) and the presence of three ELF maxima in equatorial plane of an uranyl cation attributed to the 6s and 6p electrons were demonstrated for the first time. Details of methodologies applied for additional verification of the correctness of powder XRD refinement (Voronoi atomic descriptors and the Morse restraints) are discussed

Electronic Structure of Cesium Butyratouranylate(VI) as Derived from DFT-assisted Powder X‑ray Diffraction Data

Investigation of chemical bonding and electronic structure of coordination polymers that do not form high-quality single crystals requires special techniques. Here, we report the molecular and electronic structure of the first cesium butyratouranylate, Cs­[UO₂(<i>n</i>-C₃H₇COO)₃]­[UO₂(<i>n</i>-C₃H₇COO)­(OH)­(H₂O)], as obtained from DFT-assisted powder X-ray diffraction data because of the low quality of crystalline sample. The topological analysis of the charge distribution within the quantum theory of atoms-in-molecules (QTAIM) space partitioning and the distribution of electron localization function (ELF) is reported. The constancy of atomic domain of the uranium­(VI) atom at different coordination numbers (7 and 8) and the presence of three ELF maxima in equatorial plane of an uranyl cation attributed to the 6s and 6p electrons were demonstrated for the first time. Details of methodologies applied for additional verification of the correctness of powder XRD refinement (Voronoi atomic descriptors and the Morse restraints) are discussed

Syntheses, Crystal Structures, and Nonlinear Optical Activity of Cs₂Ba[AnO₂(C₂H₅COO)₃]₄ (An = U, Np, Pu) and Unprecedented Octanuclear Complex Units in KR₂(H₂O)₈[UO₂(C₂H₅COO)₃]₅ (R = Sr, Ba)

X-ray diffraction was applied to the elucidation of crystal structures of single crystals of Cs₂Ba­[AnO₂(C₂H₅COO)₃]₄, where An = U­(<b>I</b>), Np­(<b>II</b>), Pu­(<b>III</b>), and KR₂(H₂O)₈[UO₂(C₂H₅COO)₃]₅, where R = Sr­(<b>IV</b>), Ba (polymorphs <b>V-a</b> and <b>V</b><b>-</b><b>b</b>). FTIR spectra were analyzed for the uranium-containing crystals <b>I</b>, <b>I</b><b>V</b>, and <b>V</b><b>-</b><b>b</b>. Isostructural cubic crystals <b>I</b>–<b>I</b><b>I</b><b>I</b> are constructed of typical mononuclear anionic complex units [AnO₂(C₂H₅COO)₃]⁻ and charge-balancing Cs and Ba cations. Features of actinide contraction in the six U–Np–Pu isostructural series known to date are analyzed. In crystal structures of <b>IV</b> and <b>V</b> two typical complexes [UO₂(C₂H₅COO)₃]⁻ bind with a hydrated Sr or Ba cation to form the rare trinuclear neutral complex unit {<i>R</i>(H₂O)₄[UO₂(C₂H₅COO)₃]₂}, where R = Sr, Ba. Two such trinuclear units and one typical mononuclear unit further bind with a K cation to form the unprecedented octanuclear neutral complex unit K­[UO₂(C₂H₅COO)₃]­{R­(H₂O)₄[UO₂(C₂H₅COO)₃]₂}₂. As the derived polynuclear complexes of uranyl ion with carboxylate ligands in the crystal structures of <b>IV</b> and <b>V</b> are not the first but are rare examples, the equilibrium between mono and polynuclear complex units in aqueous solutions is discussed. The two polymorphic modifications <b>V-a</b> and <b>V-b</b> were studied at 100 K and at room temperature, respectively. Peculiarities of noncovalent interactions in crystal structures of the two polymorphs are revealed using Voronoi–Dirichlet tessellation. The nonlinear optical activity of noncentrosymmetric crystals <b>I</b> was estimated by its ability for second harmonic generation