Interaction of uranyl monoaquadiformate with diaza-18-crown-6 in aqueous ethanol

The reaction of {[UO₂(HCOO)₂(H₂O)]} with diaza-18-crown-6 (DA18C6 = C₁₂H₂₆O₄N₂) in aqueous ethanol in the presence of formic acid yields the complexes {[DA18C6H₂]·[UO₂(HCOO)₃]₂} (I), [DA18C6H₂]·[UO₂(HCOO)₄] (II), and [DA18C6H₂]·(HCOO)₂·(H₂O)₂ (III). The complexes are characterized using IR spectroscopy, chemical analysis, and powder X-ray diffraction. From the comparison of the structural and spectral characteristics of [DA18C6H₂]·An₂·(H₂O)_2n (where An = Cl^?,NO ₃ ^? ,HCOO^?,HSO ₄ ^? ; n = 0.1), correlations are derived between the conformation of the [DA18C6H₂]²⁺ units and the conformation-sensitive frequencies. On the basis of these correlations, the conformations of the N⁺CCO and OCCO units were determined in the diazonia cations of compounds I and II and in [DA18C6H₂]·[UO₂(NO₃)₄]; the latter was prepared previously by reacting [UO₂(NO₃)₂(H₂O)₂]·(H₂O)₄ with DA18C6 in ethanol in the presence of nitric acid.     

Synthesis and structure of uranyl complexes with malonic acid dianions

The uranyl complexes with malonic acid dianions [UO₂(C₃H₂O₄)(CO(NH₂)₂)]·H₂O (1), [UO₂(C₃H₂O₄)(CONH₂NMe₂)]·H₂O (2), and [UO₂(C₃H₂O₄)(MeCONMe₂)] (3) were synthesized and characterized by X-ray crystallography. The structural units [UO₂(C₃H₂O₄)L] in the crystals of 1–3 refer to the AK²¹M¹ crystal chemical group (A = UO₂ ²⁺, K²¹ = C₃H₂O₄ ^2?, M¹ = L) of uranyl complexes; the crystals of 1 have a framework structure and 2 and 3 have a chain structure. Some structural features of the [UO₂(C₃H₂O₄)L] complex groups are discussed.     

Synthesis and X-ray diffraction study of Li(H<Subscript>3</Subscript>O)[UO<Subscript>2</Subscript>(C<Subscript>2</Subscript>O<Subscript>4</Subscript>)<Subscript>2</Subscript>(H<Subscript>2</Subscript>O)] · H<Subscript>2</Subscript>O

Single crystals of Li(H₃O)[UO₂(C₂O₄)₂(H₂O)] · H₂O (I) have been synthesized and studied by X-ray diffraction. Compound I crystallizes in the monoclinic crystal system with the unit cell parameters: a = 7.1682(10) Å, b = 29.639(6) Å, c = 6.6770(12) Å, β= 112.3(7)°, space group P 2₁/c, Z = 4, R = 4.36%. Structure I contains discrete mononuclear groups [UO₂(C₂O₄)₂(H₂O)]^2? ascribed to the crystal-chemical group AB ₂ ⁰¹ M¹ (A = UO₂ ²⁺, B⁰¹ =C₂O ₄ ^2? , M¹ = H₂O), which are “cross-linked” by the lithium ions into infinite layers {Li(UO₂)(C₂O₄)₂(H₂O)₂}^? perpendicular to [010]. The hydroxonium ions are located between adjacent uranium-containing layers. A hydrogen bond system involving water molecules, oxalate ions, and hydroxonium combines the anionic layers into a three-dimensional framework.     

Synthesis,crystal structures and properties of three glutarato and adipato bridged manganese(II) coordination polymers under ambient conditions

Three Mn(II) polymers Mn(H₂O)₄(C₅H₆O₄) 1, [Mn(H₂O)₂(C₅H₆O₄)]·H₂O 2 and Mn(H₂O)(C₆H₈O₄) 3 were synthesized (H₂(C₅H₆O₄) = glutaric acid, H₂(C₆H₈O₄) = adipic acid) under mild ambient conditions. The [Mn(H₂O)₂]²⁺ units in 2 are interlinked by the glutarate anions with a η⁴μ₃ bridging mode to form 2D (4·8²) topological networks, which are stacked via interlayer hydrogen bonds into a 3D (4³·6⁵·8²)(4⁷·6³) topological net. Compound 3 crystallizes in the acentric space group P2₁ and exhibits significant ferroelectricity (remnant polarization Pr = 0.371 nC cm⁻², coercive field Ec = 0.028 kV cm⁻¹, saturation of the spontaneous polarization Ps = 0.972 nC cm⁻²). The adjacent MnO₆ octahedrons in 3 are one atom-shared to generate the Mn₂O₁₁ bi-octahedron, leading into 1D metal oxide chains. The resulting chains are interconnected by the η⁵μ₅ adipate anions to form new 2D (4⁸·6²) networks, which are held together via strong interlayer hydrogen bonds into 3D α-Po topological supra-molecular architecture. The temperature-dependent magnetic susceptibility data of 1–3 shows overall anti-ferromagnetic interactions between the metal ions bridged by the carboxylate groups.     

Structure of glutarate-containing uranyl coordination polymers with organic amides

Three new uranyl complexes [UO₂(C₅H₆O₄)(Meur)] (I), [UO₂(C₅H₆O₄)(Aa)] (II), and [(UO₂)₂(C₅H₆O₄)₂(Tmur)₂(H₂O)] ? H₂O (III), where C₅H₆O₄ ^2? is glutarate anion, Meur is methylcarmamide, Aa is acetamide, and Tmur is tetramethylcarbamide, have been synthesized and characterized by X-ray diffraction. 1D uranyl-glutarate complexes have been found in the structures of all compounds; in I and II their composition is [UO₂(C₅H₆O₄)(L)] and crystallographic formula is AQ²¹M¹ (where A = UO₂ ²⁺, Q²¹ = C₅H₆O₄ ^2-, and M¹ = L = Meur or Aa). In crystals III, chain complexes have the composition [(UO₂)₂(C₅H₆O₄)₂(Tmur)₂(H₂O)] and crystallographic formula A₂Q₂ ⁰²M₃ ¹ (where A = UO₂ ²⁺, Q⁰² = C₅H₄O₆ ^2-, and M¹ = Tmur or H₂O). All compounds were characterized by IR spectroscopy. Structural features of all known complexes of uranyl glutarate with neutral ligands have been discussed.     

Hydroxyl Ammonium and Diethyl Ammonium Glutaratouranylates: Synthesis and Structure

The structures of two new coordination polymers, namely, hydroxyl ammonium glutaratouranylate NH₃OH[UO₂(C₅H₆O₄)(C₅H₇O₄)] · H₂O (I) and diethyl ammonium glutaratouranylate NH₂(C₂H₅)₂[UO₂(C₅H₆O₄) (C₅H₇O₄)] · 2H₂O (II), have been characterized by single-crystal X-ray diffraction. It has been established that the structures of complexes I and II contain [UO₂(C₅H₆O₄)(C₅H₇O₄)]–infinite chains with the crystallochemical formula AQ⁰²B⁰¹ (\(\rm{A = UO_2^{2+}}, Q^{02} = C_5H_6O_4^{2-}, B^{01} = C_5H_7O_4^{-}\)). Despite the identical compositions, uranyl glutarate chains in the studied structures appreciably differ from each other by their geometry and linking. The specific features of nonbonded interactions in the structures of complexes I and II have been characterized by the Voronoi–Dirichlet method of molecular polyhedra.     

Crystal structure of (C2H7N4O)2[UO2(C2O4)2(H2O)]

The single crystals of (C₂H₇N₄O)₂[UO₂(C₂O₄)₂(H₂O)] were studied by X-ray diffraction. The crystals are monoclinic, space group Pn, Z = 2, unit cell parameters: a = 9.4123(2) Å, b = 8.4591(2) Å, c = 11.8740(3) Å, β = 105.500(10)°, V = 911.02(4) ų. The main structural units of the crystals of I are islet complex groups [UO₂(C₂O₄)₂(H₂O)]^2? corresponding to the crystal chemical group AB ₂ ⁰¹ M¹ (A = UO UO ₂ ²⁺ , B⁰¹ = C₂O ₄ ^2? , M = H₂O) of uranyl complexes. Uranium-containing mononuclear complexes are connected into a three-dimensional framework through the electrostatic interactions and hydrogen bonding system involving carbamyolguanidinium ions.     

Uranyl α-dioximates with neutral ligands

The interaction of uranyl compounds with different α-dioximes has been studied. Uranyl complexes with glyoxime, methylglyoxime, dimethylglyoxime, and 1,2-cyclohexanedionedioxime have been synthesized. The X-ray diffraction study of single crystals of [UO₂(C₃H₅N₂O₂)₂{(NH₂)₂CO}₂], [UO₂(C₆H₉N₂O₂)₂(H₂O)₂] · H₂O, [UO₂(C₆H₉N₂O₂)₂(H₂O)₂] · 6H₂O, and [UO₂(C₆H₉N₂O₂)₂(H₂O)₂]₂(CH₃CONH₂)₂ · 6H₂O showed a bidentate cyclic coordination of α-dioximes to the central atom through only one oxime group     

“Forced” coordination modes of 1,2-cyclohexanedione dioxime in uranyl complexes

Unusual coordination modes of 1,2-cyclohexane dionedioxime in uranyl complexes, i.e., tridentate chelating/bridging and (E, Z)-pentadentate chelating/bridging ones, were established by X-ray crystallography of single crystals of (CN₃H₆)₃[(UO₂)₂(C₆H₉N₂O₂)(C₆H₈N₂O₂)(C₂O₄)₂] · 2H₂O and [(UO₂)₂(C₆H₈N₂O₂)₂(H₂O)₃] · 2H₂O. The conditions of the emergence of such coordination modes were determined. The possibility of (E/Z) izomerization of α-dioximes in reactions of uranyl complexes.     

Neutron diffraction study of uranyl oxalate [UO2(C2O4)(D2O)] · 2D2O

A powdered sample of uranyl oxalate [UO₂(C₂O₄)(D₂O)] · 2D₂O (compound I) is studied using neutron diffraction. The crystals are monoclinic, space group P2₁/c, with a = 5.608(1) Å, b = 17.016(3) Å, c = 9.410(2) Å, β = 98.9369(2)°, Z = 4, R _f = 0.042, R _I = 0.054, x ² = 1.5. The main structural units of the crystals are [UO₂(C₂O₄)(D₂O)] chains. These chains, which belong to the AK⁰²M¹ (A = UO ₂ ²⁺ ) crystal-chemical group of the uranyl complexes, lie parallel to [101]. The water molecules in the crystals of I are hydrogen-bonded into zigzag chains running along [100]. Since each third oxygen atom of the chain formed of water molecules is coordinated to the uranium atom, the uranyl oxalate chains are linked into {[UO₂(C₂O₄)(D₂O)] · 2D₂O} layers that lie normal to [010]. The layers are linked into the framework through interlayer hydrogen bonds (D₂O)O-D···O (oxalate).     

Supramolecular approach to crystallization of polynuclear chromium(III) aqua hydroxo complexes: synthesis and crystal structures of complexes [Cr2(OH)2(H2O)8]4+ and [Cr4(OH)6(H2O)12]6+ with cucurbit[n]uril (n = 7, 8)

Supramolecular compounds of the compositions {[Cr₂(OH)₂(H₂O)₈](C₄₂H₄₂N₂₈O₁₄)₂}-(NO₃)₄·18.75H₂O (1) and {[Cr₄(OH)₆(H₂O)₁₂](C₄₈H₄₈N₃₂O₁₆)₃(NO₃)₆·55H₂O (2) were synthesized from aqueous solutions of chromium(III) nitrate and the macrocyclic cavitand cucurbit[n]uril (C_6n H_6n N_4n O_2n , where n = 7 or 8, respectively). According to the X-ray diffraction study, the polynuclear chromium aqua complexes are disposed in cavities formed by the cucurbit[n]uril molecules and are linked to these molecules through hydrogen bonds between the hydroxo and aqua ligands of the polycations and the portal oxygen atoms of the macrocycles. Compound 1 is the first example of supramolecular compounds of cucurbit[7]uril with metal aqua complexes. The isolation of the supramolecular adduct with cucurbit[8]uril 2 in the single-crystalline state allows the determination of the structure of the tetranuclear chromium aqua complex having an adamantane-like structure, [Cr₄(μ₂-OH)₆(H₂O)₁₂]⁶⁺, which has been previously unknown in the solid state.     

Metal complexes of tetradentate and pentadentate N-o-hydroxybenzamido-meso-tetraphenylporphyrin ligand: M(N-NCO(o-OH)C6H4-tpp) (M = Zn2+, Ni2+, Cu2+) and M′(N-NCO(o-O) C6H4-tpp) (M′ = Mn3+) (tpp = 5, 10, 15, 20-tetraphenylporphyrinate)

The crystal structures of N-o-hydroxybenzimido-meso-tetraphenylporphyrinatozinc(II) toluene solvate [Zn(N-NCO(o-OH)C₆H₄-tpp)·C₆H₅CH₃; 4·C₆H₅CH₃], N-o-hydroxybenzimido-meso-tetraphenylporphyrinatonickel(II) chloroform solvate [Ni(N-NCO(o-OH)C₆H₄-tpp)·0.6CHCl₃; 5·0.6 CHCl₃], N-o-hydroxybenzimido-meso-tetraphenylporphyrinatocopper(II) toluene solvate [Cu(N-NCO(o-OH)C₆H₄-tpp)·C₆H₅CH₃; 6·C₆H₅CH₃] and N-o-oxido-benzimido-meso-tetraphenylporphyrinato(-κ⁴,N¹,N²,N³,N⁵,κO²) manganese (III) methylene chloride·methanol solvate [Mn(N-NCO(o-O)C₆H₄-tpp)·CH₂Cl₂·MeOH; 8·CH₂Cl₂·MeOH] were established. The coordination sphere around Zn²⁺ ion in 4·C₆H₅CH₃, (or Ni²⁺ ion in 5·0.6 CHCl₃ or Cu²⁺ ion in 6·C₆H₅CH₃) is a distorted square planar (DSP) whereas for Mn³⁺ in 8·CH₂Cl₂·MeOH, it is a distorted trigonal bipyramid (DTBP) with O(1), N(1) and N(3) lying in the equatorial plane for 8·CH₂Cl₂·MeOH. The g value of 8.27 measured from the parallel polarization of X-band EPR spectra at 293 K is consistent with the high-spin mononuclear manganese(III) (S = 2) in 8. The magnitude of axial (D) zero-field splitting (ZFS) for the mononuclear Mn(III) in 8 was determined approximately as 3.0 cm^?1 by the paramagnetic susceptibility measurements and conventional EPR spectroscopy.     

Crystal structures of the dicyclohexyl-(18-crown-6) uranyl perchlorate complex and of its hydrolysis product

The structures of dicyclohexyl-(18-crown-6) uranyl perchlorate, [(C₂₀H₃₆O₆)UO₂] (ClO₄)₂ (complex I) and of dicyclohexyl-(18-crown-6) uranyl hydroxyperchlorate [C₂₀H₃₆O₆]₃ [(UO₂)₂(H₂O)₆] · (ClO₄)₂, CH₃CN, (complex II) have been determined from three dimension X-ray diffraction data.The uranyl group is directly coordinated to the oxygen atoms of the polyether ring in complex I; its hydrolysis (complex II) leads to a dimerization of the uranyl ions by sharing two OH groups with an U-U distance of only 3.827(8) Å. The polyether molecules are connected by hydrogen bonds with the dimeric ion [(UO₂)₂ (OH)₂ (H₂O)₆]²⁺.     

(NH4)(CN3H6)2[UO2(C2O4)2(NCS)] · 2H2O: Synthesis and crystal structure

A single-crystal X-ray diffraction study (NH₄)(CN₃H₆)₂[(UO₂(C₂O₄)₂(NCS)] · 2H₂O (I) was carried out. The crystals are orthorhombic, space group P2₁2₁2₁, Z = 4, with the unit cell parameters a = 6.668(2) Å, b = 13.463(4) Å, c = 23.086(6) Å. The main structural units of the crystals of I are insular complex anions [(UO₂)(C₂O₄)₂(NCS)]^3?. They belong to the crystal-chemical group AB ₂ ⁰¹ M¹ (A = UO ₂ ²⁺ ) of uranyl complexes and are linked into a three-dimensional framework through electrostatic interactions and hydrogen bonds with the participation of ammonium and guanidinium cations and crystal water molecules.     

Synthesis and structure of [C6H14N2][(UO2)4(HPO4)2(PO4)2(H2O)]·H2O: An expanded open-framework amine-bearing uranyl phosphate

A new open-framework compound, [C₆H₁₄N₂][(UO₂)₄(HPO₄)₂(PO₄)₂(H₂O)]·H₂O, (DUP-1) has been synthesized under mild hydrothermal conditions. The resulting structure consists of diprotonated DABCOH₂²⁺ (C₆H₁₄N₂²⁺) cations and occluded water molecules occupying the channels of a complex uranyl phosphate three-dimensional framework. The anionic lattice contains uranophane-like sheets connected by hydrated pentagonal bipyramidal UO₇ units. [C₆H₁₄N₂][(UO₂)₄(HPO₄)₂(PO₄)₂(H₂O)]·H₂O possesses five crystallographically unique U centers. U(VI) is present here in both six- and seven-coordinate environments. The DABCOH₂²⁺ cations are held within the channels by hydrogen bonds to both two uranyl oxygen atoms and a μ₂-O atom. Crystallographic data (193 K, Mo Kα, λ=0.71073 Å): DUP-1, monoclinic, P2₁/n, a=7.017(1) Å, b=21.966(4) Å, c=17.619(3) Å, β=90.198(3)°, Z=4, R(F)=4.76% for 382 parameters with 6615 reflections with I>2σ(I).     

Hydrothermal synthesis and structure of K6[(UO2)4(CrO4)7]·6H2O: A layered uranyl chromate with a new uranyl sheet topology

The layered uranyl chromate, K₆[(UO₂)₄(CrO₄)₇]·6H₂O (1), has been synthesized by reacting UO₃ with K₂Cr₂O₇ under mild hydrothermal conditions. The structure of 1 is formed from UO₂²⁺ cations that are bound by chromate anions to yield a pentagonal bipyramidal geometry around the uranium centers. These polyhedra are bridged by chromate anions to yield one-dimensional _∞¹[UO₂(CrO₄)₂]²⁻ chains. The chains are similar to the _∞¹[UO₂(CrO₄)₂(H₂O)]²⁻ chains found in the previously reported one-dimensional uranyl chromate, K₂[UO₂(CrO₄)₂(H₂O)]·3H₂O, a phase that forms concomitantly with 1. These chains are condensed with the loss of the coordinated water molecules into two-dimensional _∞²[(UO₂)₄(CrO₄)₇]⁶⁻ layers with additional one-dimensional _∞¹[(UO₂)₂(CrO₄)₃]²⁻ chains. These anionic layers form a new type of anionic sheet topology and are charge balanced by both intra- and interlayer K⁺ cations. Crystallographic data (193 K): 1, orthorhombic, space group P2₁2₁2, a=10.9583(5) Å, b=22.582(1) Å, c=7.9552(4) Å, Z=2, MoKα, λ=0.71073, R(F)=1.77% for 268 parameters with 4657 reflections with I>2σ(I).     

Effect of N-donor sites of bis-pyridyl-bis-amide ligands on the architectures of three Anderson-type polyoxometalate-based metal–organic complexes

Three polyoxometalate-based metal–organic complexes [Co₂(H₂O)₆(TeMo₆O₂₄)](3-H₂dpyb)·2H₂O (1), [M₂(4-Hdpyb)₂(H₂O)₆(TeMo₆O₂₄)]·6H₂O [M = Co (2), Zn (3); 3-dpyb = N,N′-bis(3-pyridinecarboxamide)-1,4-butane, 4-dpyb = N,N′-bis(4-pyridinecarboxamide)-1,4-butane] have been hydrothermally synthesized and characterized by elemental analysis, IR, TG, powder diffraction and single-crystal X-ray diffraction analysis. The structure of complex 1 consists of 1D [Co₂(H₂O)₆(TeMo₆O₂₄)] inorganic chains, which are joined together by the 3-dpyb ligands through weak hydrogen bonds to generate a 2D supramolecular network. Complexes 2 and 3 are isostructural; each [TeMo₆O₂₄]^6? (TeMo₆) polyoxoanion chelates either two cobalt or two zinc atoms to generate the discrete complexes [Co₂(4-Hdpyb)₂(H₂O)₆(TeMo₆O₂₄)] and [Zn₂(4-Hdpyb)₂(H₂O)₆(TeMo₆O₂₄)], respectively. The electrochemical properties, electrocatalytic and photocatalytic activities of the complexes have been investigated.     

A Novel Three-Dimensional Network Isophthalato-Bridged Lanthanide Complex: {Ln[C6H4(COO−)2-1,3](CH3COO−)(H2O)2}·H2O

The three-dimensional network of lanthanide (III) complexes with isophthalato (IPT) ligand, (Eu[C₆H₄(COO^?)₂-1,3](CH₃COO^?)(H₂O)₂}·H₂O 1 and {Sm[C₆H₄(COO^?)₂-1,3](CH₃COO^?) (H₂O)₂} H₂O 2, has been prepared by the hydro(solvo)thermal reaction of Eu(C1O₄)₃·6H₂O or Sm(C1O₄)₃·6H₂O, 1,3-dicyanobenzene and acetic acid in the presence of ethanol and H₂O. In the reaction, 1,3-dicyanobenzene was hydrolyzed to give IPT ligand. Single crystal x-ray analysis revealed that crystals 1 and 2 are isomorphous with the isostructural {M[C₆H₄(COO^?)₂-1,3](CH₃COO^?)(H₂O)₂}·H₂O unit. In 1 and 2, IPT acts as a bridging ligand to connect three adjacent metal atoms, forming a network like an undulating sheet paralleling the bc plane. The carboxylate from acetate bridges two adjacent metal atoms in a tridentate mode between the different sheets to extend the structure into a three-dimensional network.     

Crystal structure of a new supramolecular Ni(II) N 6-benzylaminopurine compound

A new mononuclear Ni(II) N ⁶-benzylaminopurine supramolecule [Ni(6-BA-H₂)₂(H₂O)₄]·(R)₂·4H₂O (1) (6-BA = N ⁶-benzylaminopurine (C₅H₂N₃NH)(NH)CH₂(C₆H₅), H₃R = 5-sulfosalicylic acid (C₆H₃)CO₂H· (OH)SO₃H) is firstly synthesized by the volatile method. Compound 1 possesses a 3D supramolecular structure built via H-bonds and π-π stacking interactions. In the structure, a mononuclear [Ni(6-BA-H₂)₂(H₂O)₄]⁶⁺ cation, in which the Ni(II) ion is 6-coordinated, bears six positive charges, and a fully deprotonated R^3? anion is located in the void surrounding the mononuclear cation to balance the charge.     

New fluorochromatouranylates of alkali metals: Synthesis and structure

Four new fluorochromatouranylates, namely, K[UO₂(CrO₄)F] · 1.5H₂O (I), Rb[UO₂(CrO₄)F] · 1.5H₂O (II), Rb[UO₂(CrO₄)F] · 0.5H₂O (III), and Cs[UO₂(CrO₄)F] · 0.5H₂O (IV), have been synthesized, and their crystallographic characteristics have been determined. All the compounds crystallize in monoclinic system, space group P2₁/c, with the unit cell parameters a = 13.1744(5) Å, b = 9.4598(3) Å, c = 13.0710(4) Å, β = 103.746(1)°, Z = 4, R = 0.0235 (I); a = 13.5902(7) Å, b = 9.5022(4) Å, c = 13.2271(6) Å, β = 102.914(2)°, Z = 4, R = 0.0247 (II); a = 24.7724(8) Å, b = 12.6671(4) Å, c = 9.4464(3) Å, β = 97.661(1)°, Z = 8, R = 0.0448 (III); a = 25.725(1) Å, b = 12.8261(5) Å, c = 9.4929(4) β = 97.208(1)°, Z = 8 (IV). The pairs of compounds I and II and compounds III and IV are isostructural. Crystals of compounds I–III have been subjected to complete X-ray diffraction study. It has been established that the structures of compounds I–III are built of [UO₂(CrO₄)F] _n ^n? layers, which are parallel to the (100) plane and linked into a framework by alkali-metal cations located between layers, together with water molecules. The effect of topological and geometric isomerism on the structural features of 34 known uranyl compounds of the AT³M² crystallochemical group, to which the studied compounds I–III also belong, is discussed.