[Hg5O2(OH)4][(UO2)2(AsO4)2]: A complex mercury(II) uranyl arsenate

Under mild hydrothermal conditions UO₂(NO₃)₂·6H₂O, Hg₂(NO₃)₂·2H₂O, and Na₂HAsO₄·7H₂O react to form [Hg₅O₂(OH)₄][(UO₂)₂(AsO₄)₂] (HgUAs-1). Single crystal X-ray diffraction experiments reveal that HgUAs-1 possesses a pseudo-layered structure consisting of two types of layers: and . The layers are complex, and contain three crystallographically unique Hg centers. The coordination environments and bond-valence sum calculations indicate that the Hg centers are divalent. The layers belong to the Johannite topological family. The and layers are linked to each other through μ₂-O bridges that include Hg?O=U=O interactions.     

Layered metal phosphonates containing pyridyl groups: Syntheses and characterization of Mn2(2-C5H4NPO3)2(H2O) and Zn(6-Me-2-C5H4NPO3)

This paper reports the syntheses and characterization of two phosphonate compounds with layered structures, namely, Mn₂(2-C₅H₄NPO₃)₂(H₂O) (1) and Zn(6-Me-2-C₅H₄NPO₃) (2). In compound 1, double chains are found in which the {Mn₂O₂} dimers are linked by both aqua and O-P-O bridges. These double chains are connected through corner-sharing of {MnO₅N} octahedra and {CPO₃} tetrahedra, forming an inorganic layer. The pyridyl groups fill the inter-layer spaces. In compound 2, each {ZnO₃N} tetrahedron is vertex-shared with three {CPO₃} tetrahedra and vice versa, hence forming an inorganic honeycomb layer. The pyridyl groups reside between the layers. Magnetic studies show that weak antiferromagnetic interactions are mediated between the manganese ions in compound 1. Crystal data for 1: monoclinic, space group C2/c, , , , β=107.3(1)°. For 2: orthorhombic, space group Pbca, , , .     

Low-temperature flux syntheses and characterizations of two 1-D anhydrous borophosphates: Na3B6PO13 and Na3BP2O8

Two new anhydrous sodium borophosphates with one-dimensional structure, Na₃B₆PO₁₃(1) and Na₃BP₂O₈(2), were synthesized by low-temperature molten salts techniques using boric acid and sodium dihydrogen phosphate as flux, respectively. The crystal structures were solved by means of single-crystal X-ray diffraction (1, orthorhombic, Pnma (no. 62), , , , Z=4; 2 , monoclinic, C2/c (no. 15), , , , β=92.492(5)°, Z=8). Compound 1 is characterized by an infinite chain of containing eight-membered rings in which all vertexes of borate groups contribute to interconnection. Compound 2 reveals an infinite straight chain built of vertex-sharing four-membered rings, and chains in neighboring layers arranged along different orientations. The relations between structures and the synthetic conditions with only traced water are discussed.     

[Zn2(HPO3)2(H2PO3)][C3H5N2] and [Zn2(HPO3)3][C4H7N2]2·2H2O: Two new layered zinc phosphites with double 12-membered rings templated by imidazole and 2-methylimidazole

Two new zinc phosphites [Zn₂(HPO₃)₂(H₂PO₃)][C₃H₅N₂] 1 and [Zn₂(HPO₃)₃][C₄H₇N₂]₂·2H₂O 2 have been hydrothermally synthesized templated by imidazole and 2-methylimidazole. Single-crystal X-ray diffraction analysis reveals that the two compounds have the similar inorganic framework structures, which both exhibit 2D double layer structures with double 12-membered rings. Due to the different space-filling effect of the guest molecules, the stacking mode of adjacent layers and the arrangement mode of the organic amines are distinct. In 1, the adjacent layers are stacked in an -ABAB- sequence and monoprotonated imidazole molecules sit in the middle of 12MR windows, while in 2, the layers are stacked in an -AAAA- pattern. Monoprotonated 2-methylimidazole molecules occupy two different sites, one inserts into 12MR and the other resides in the interlayer region. Crystal data for 1: triclinic, P-1, , , , α=114.71(3)°, β=92.78(3)°, γ=113.04(3)°, , Z=2; for 2: triclinic, P-1, , , , α=68.244(7)°, β=76.143(7)°, γ=63.113(6)°, , Z=2.     

A TEM study of Ni ordering in the Ni6Se5−xTex, 0<x<∼1.7, system

The Ni₆Se_5−xTe_x, 0<x<∼1.7, system has been carefully investigated via electron diffraction and TEM imaging. They reveal a somewhat disordered modulated superstructure phase arising from Ni ion ordering within an essentially well-defined chalcogen sub-structure. As x, and the underlying parent substructure cell dimensions increase, the incommensurate primary modulation wave-vector q characteristic of this Ni ion ordering quickly swings from close to for x=0 towards for x?0.5. A lock-in to would formally transform the underlying parent Bmmb (a_p, b_p, c_p) structure into a P1a1 (a_s=2a_p, b_s=b_p, c_s=a_p+c_p) superstructure phase.     

Synthesis and crystal structures of the layered uranyl tellurites A2[(UO2)3(TeO3)2O2] (A=K, Rb, Cs)

The reactions of UO₃ and TeO₃ with KCl, RbCl, or CsCl at 800 °C for 5 d yield single crystals of A₂[(UO₂)₃(TeO₃)₂O₂] (A=K (1), Rb (2), and Cs (3)). These compounds are isostructural with one another, and their structures consist of two-dimensional sheets arranged in a stair-like topology separated by alkali metal cations. These sheets are comprised of zigzagging uranium(VI) oxide chains bridged by corner-sharing trigonal pyramidal TeO₃²⁻ anions. The chains are composed of dimeric, edge-sharing, pentagonal bipyramidal UO₇ moieties joined by edge-sharing tetragonal bipyramidal UO₆ units. The lone-pair of electrons from the TeO₃ groups are oriented in opposite directions with respect to one another on each side of the sheets rendering each individual sheet non-polar. The alkali metal cations form contacts with nearby tellurite oxygen atoms as well as with oxygen atoms from the uranyl moieties. Crystallographic data (193 K, MoKα, ): 1, triclinic, space group , , , , α=101.852(1)°, β=102.974(1)°, γ=100.081(1)°, , Z=2, R(F)=2.70% for 98 parameters and 1697 reflections with I>2σ(I); 2, triclinic, space group , , , , α=105.590(2)°, β=101.760(2)°, γ=99.456(2)°, , Z=2, R(F)=2.36% for 98 parameters and 1817 reflections with I>2σ(I); 3, triclinic, space group , , , , α=109.301(1)°, β=100.573(1)°, γ=99.504(1)°, , Z=2, R(F)=2.61% for 98 parameters and 1965 reflections with I>2σ(I).     

Structural characterization and ferroelectric ordering in (C3N2H5)5Sb2Br11

A ferroelectric crystal (C₃N₂H₅)₅Sb₂Br₁₁ has been synthesized. The single crystal X-ray diffraction studies (at 300, 155, 138 and 121 K) show that it is built up of discrete corner-sharing bioctahedra and highly disordered imidazolium cations. The room temperature crystal structure has been determined as monoclinic, space group, P2₁/n with: , and and β=96.19^°. The crystal undergoes three solid-solid phase transitions: ) discontinuous, continuous and discontinuous. The dielectric and pyroelectric measurements allow us to characterize the low temperature phases III and IV as ferroelectric with the Curie point at 145 K and the saturated spontaneous polarization value of the order of along the a-axis (135 K). The ferroelectric phase transition mechanism at 145 K is due to the dynamics of imidazolium cations.     

Synthesis and characterization of two new open-framework zinc phosphites [M(C6N4H18)][Zn3(HPO3)4] (M=Ni, Co) with multi-directional intersecting 12-membered ring channels

Two new open-framework zinc phosphites, [M(C₆N₄H₁₈)][Zn₃(HPO₃)₄] (M=Ni, Co), have been prepared under hydrothermal conditions. Single-crystal X-ray diffraction analysis shows that [Ni(C₆N₄H₁₈)][Zn₃(HPO₃)₄] (1) and [Co(C₆N₄H₁₈)][Zn₃(HPO₃)₄] (2) are isostructural and both crystallize in the monoclinic space group C2/c with , , , β=109.83(3)°, Z=4, R₁=0.0408 (I>2σ(I)), and wR₂=0.1104 (all data) for 1, and , , , β=109.328(2)°, Z=4, R₁=0.0380 (I>2σ(I)), and wR₂=0.1093 (all data) for 2. The structures of 1 and 2 are built up from strictly alternating ZnO₄ tetrahedra and HPO₃ pseudo-pyramids linked through oxygen vertices to form the three-dimensional (3-D) open-frameworks with multi-directional intersecting 12-membered ring (12-MR) channels. The M(TETA) (M=Ni, Co) complexes self-assembled under hydrothermal system connect with the inorganic host via M-O-P linkages and interact with inorganic framework through weak H-bonds. The two compounds show intense photoluminescence upon photoexcitation at 235 nm.     

Extended networks, porous sheets, and chiral frameworks. Thorium materials containing mixed geometry anions: Structures and properties of Th(SeO3)(SeO4), Th(IO3)2(SeO4)(H2O)3·H2O, and Th(CrO4)(IO3)2

Three novel Th(IV) compounds containing heavy oxoanions, Th(SeO₃)(SeO₄) (1), Th(IO₃)₂(SeO₄)(H₂O)₃·H₂O (2), and Th(CrO₄)(IO₃)₂ (3), have been synthesized under mild hydrothermal conditions. Each of these three distinct structures contain trigonal pyramidal and tetrahedral oxoanions. Compound 1 adopts a three-dimensional structure formed from ThO₉ tricapped trigonal prisms, trigonal pyramidal selenite, SeO₃^2-, anions containing Se(IV), and tetrahedral selenate, SeO₄^2-, anions containing Se(VI). The structure of 2 contains two-dimensional porous sheets and occluded water molecules. The Th centers are found as isolated ThO₉ tricapped trigonal prisms and are bound by four trigonal pyramidal iodate anions, two tetrahedral selenate anions, and three coordinating water molecules. In the structure of 3, the Th(IV) cations are found as ThO₉ tricapped trigonal prisms. Each Th center is bound by six IO₃^1- anions and three CrO₄^2- anions forming a chiral three-dimensional structure. Second-harmonic generation of 532 nm light from 1064 nm radiation by a polycrystalline sample of 3 was observed. Crystallographic data (193 K, MoKα, λ=0.71073): 1; monoclinic, P2₁/c; , , , β=103.128(1), Z=4, R(F)=2.47% for 91 parameters with 1462 reflections with I>2σ(I); 2, monoclinic, P2₁/n, , , , β=100.142(2), Z=4, R(F)=4.71% for 158 parameters with 2934 reflections with I>2σ(I); 3, orthorhombic, P2₁2₁2₁, , , , Z=4, R(F)=2.04% for 129 parameters with 2035 reflections with I>2σ(I).     

Synthesis, structural determination and magnetic properties of layered hybrid organic-inorganic, iron (II) propylphosphonate, Fe[(CH3(CH2)2PO3)(H2O)], and iron (II) octadecylphosphonate, Fe[(CH3(CH2)17PO3)(H2O)]

Fe[(CH₃(CH₂)₂PO₃)(H₂O)] (1) and Fe[(CH₃(CH₂)₁₇PO₃)(H₂O)] (2) were synthesized by reaction of FeCl₂·6H₂O and the relevant phosphonic acid in water in presence of urea and under inert atmosphere. The compounds were characterized by elemental and thermogravimetric analyses, UV-visible and IR spectroscopy. The crystal structure of (1) was determined from X-ray single crystal diffraction studies at room temperature: monoclinic symmetry, space group P2₁, , , , and β=98.62(3)°. The compound is lamellar and the structure is hybrid, made of alternating inorganic and organic layers along the c direction. The inorganic layers consist of Fe(II) ions octahedrally coordinated by five phosphonate oxygen atoms and one from the water molecule, separated by bi-layers of propyl groups. A preliminary structure characterization of compound (2) suggests a similar layered structure, but with an interlayer spacing of 40.3 Å. The magnetic properties of the compounds were both studied by a dc and ac SQUID magnetometer. Fe[(CH₃(CH₂)₂PO₃)(H₂O)] (1) obeys the Curie-Weiss law at temperatures above 50 K (, ), indicating a Fe +II oxidation state, a high-spin d⁶ (S=2) electronic configuration and an antiferromagnetic exchange couplings between the near-neighbouring Fe(II) ions. Below , Fe[(CH₃(CH₂)₂PO₃)(H₂O)] exhibits a weak ferromagnetism. The critical temperature of has been determined by ac magnetic susceptibility measurements. Compound (2) shows the same paramagnetic behaviour of the iron (II) propyl derivative. The values of C and θ were found to be and −44 K, respectively, thus suggesting the presence of Fe +II ion in the S=2 spin state and antiferromagnetic interactions between Fe(II) ions at low temperatures. Zero-field and field cooled magnetic susceptibility vs. T plots do not overlap below , suggesting the presence of an ordered magnetic state. The critical temperature, T_N, has been located by the peaks at from the ac susceptibility (χ′and χ″) vs. T plots. Below T_N hysteresis loops recorded in the temperature region show an S-shape, while below 15 K assume an ellipsoid form. They reveal that compound (2) is a weak ferromagnet. The critical temperature T_N in these layered Fe(II) alkylphosphonates is independent of the distance between the inorganic layers.     

Design and synthesis of four coordination polymers generated from 2,2′-biquinoline-4,4′-dicarboxylate and aromatic bidentate ligands

Four coordination polymers [Zn(bqdc)(phen)]_n (1), [Zn(bqdc)(bpy)(H₂O)]_n (2), [Mn(bqdc)(bpy)(H₂O)₂]_n (3) and [Mn(bqdc)(phen)(H₂O)₂]_n (4) (H₂bqdc=2,2′-biquinoline-4,4′-dicarboxylic acid, phen=1,10-phenanthroline and bpy=2,2′-bipyridyl) have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction. Crystal data for 1: monoclinic system, C2/c, , , , β=103.78(3)°, , Z=4. Crystal data for 2: monoclinic system, p2₁/n, , , , β=107.13(7)°, , Z=4. Crystal data for 3: monoclinic system, C2/c, , , , β=116.8010(11)°, , Z=4. Crystal data for 4: monoclinic system, C2/c, , , , β=117.04(3)°, , Z=4. Single helix-like chains exist in 1. The supramolecular structure of 1 exhibits extended two-dimensional network while 2-4 display extended three-dimensional architectures based on interchain hydrogen bonding and π-π interactions. Compounds 1 and 2 show blue photoluminescence under UV light suggesting that they may be employed to develop luminescent materials. Compounds 3 and 4 show interesting magnetic behaviors.     

Pyridinium amide-based simple synthetic receptor for selective recognition of dihydrogenphosphate

A new fluorescent receptor 1 built on biphenyl motif has been designed and synthesized. Pyridinium amide moiety in 1 acts as binding site and shows selective complexation of isophthalate and under the mastery of biphenyl spacer. Binding-induced increase in emission was used to determine the selectivity and sensitivity of 1 toward a series of anions such as different dicarboxylates, , , and . The binding characteristics were established by ¹H NMR, UV-vis, and fluorescence spectroscopic methods.     

Solvothermal synthesis, crystal structure, magnetic and luminescent properties of (H3O)6·[Co4(H2O)4(HPMIDA)2(PMIDA)2)]·2H2O

A cobalt phosphonate (H₃O)₆·[Co₄(H₂O)₄(HPMIDA)₂(PMIDA)₂)]·2H₂O, 1, has been synthesized from a mild solvothermal reaction of Co(II) ion with N-(phosphonomethyl)iminodiacetic acid (H₄PMIDA). Compound 1 crystallizes in the triclinic space group with cell parameters of , , , α=93.06(3)°, β=99.66(3)°, γ=90.34(3)° and Z=1. Compound 1 shows a novel tetra-nuclear molecular structure. In the crystal lattice, molecules of 1 hydrogen bond to each other to form two-dimensional (2D) layers, which are further linked together by the co-crystallized H₂O molecules and H₃O⁺ counter ions through hydrogen bonding to form the 3D supramolecular network. Thermogravimetric analysis, IR spectrum, magnetic susceptibility and luminescent spectra are given.     

Syntheses and crystal structures of three new borates templated by transition-metal complexes in situ

Three new cobalt borate compounds, [Co(DIEN)₂][B₅O₆(OH)₄]₂ (DIEN=diethylenetriamine) (1), [B₅O₇(OH)₃Co(TREN)] (TREN=tris(2-aminoethyl)amine) (2), and [Co₂(TETA)₃][B₅O₆(OH)₄]₄ (TETA=triethylenetetramine) (3) have been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction, IR, elemental analysis and thermogravimetry. The structures exhibit interesting 3D supramolecular hydrogen-bonded architectures, involving the similar borate polyanion [B₅O_6+n(OH)_4−n]⁽ⁿ⁺¹⁾⁻(n=0 for 1 and 3, and n=1 for 2) and the templating transition metal complexes which are generated in situ under mild solvothermal conditions. Crystal data: 1, monoclinic, space group C2/m (No. 12), , , , β=93.601(4)°, , Z=2; 2, monoclinic, P2₁/c (No. 14), , , , β=99.926(4)°, , Z=4; 3, triclinic, space group P-1 (No. 2), , , , α=77.009(5)°, β=80.095(2)°, γ=82.334(3)°, , Z=2.     

Synthesis and structure of three manganese oxalates: MnC2O4·2H2O, [C4H8(NH2)2][Mn2(C2O4)3] and Mn2(C2O4)(OH)2

Three manganese oxalates have been hydrothermally synthesized, and their structures determined by single-crystal X-ray diffraction. MnC₂O₄·2H₂O (I) is orthorhombic, P2₁2₁2₁, , , , , Z=4, final R, R_w=0.0832, 0.1017 for 561 observed data (I>3σ(I)). The one-dimensional structure consists of chains of oxalate-bridged manganese centers. [C₄H₈(NH₂)₂][Mn₂(C₂O₄)₃] (II) is triclinic, , , , , α=81.489(2)°, β=81.045(2)°, γ=86.076(2)°, , Z=1, final R, R_w=0.0467, 0.0596 for 1773 observed data (I > 3σ (I)). The three-dimensional framework is constructed from seven coordinate manganese and oxalate anions. The material contains extra-framework diprotonated piperazine cations. Mn₂(C₂O₄)(OH)₂ (III) is monoclinic, P2₁/c, , , , β=91.10(3)°, , Z=1, final R₁, wR2=0.0710, 0.1378 for 268 observed data (I>2σ (I)). The structure is also three dimensional, with layers of MnO₆ octahedra pillared by oxalate anions. The hydroxide group is found bonded to three manganese centers resulting in a four coordinate oxygen.     

Self-assembly of silver polymers based on flexible isonicotinate ligand at different pH values: syntheses, structures and photoluminescent properties

Two interesting coordination polymers, [Ag₈(IN)₆(NO₃)₂] 1 and [Ag(IN)(HIN)]_1/2 [Ag(IN)] 2 (HIN=isonicotinic acid) have been synthesized hydrothermally at different pH values. 1 crystallizes in the triclinic space group P-1, with , , , α=75.87(3)°, β=80.87(3)°, γ=76.50(3)°, and Z=2. Compound 1 is the first example of a bilayer framework, in which both single layers are connected by the bond interactions (Ag-O) between Ag from two two-dimensional (2D) single layers generated by the A building block and O atoms from one-dimensional (1D) chain constructed by the B building block, in which coordination modes of IN were reported for the first time. 2 crystallizes in the monoclinic space group P2(1)/c, with , , , β=92.90(3)°, V=1185.0(4) and Z=4. Compound 2 exhibits a 2D plywood-like structure assembled by hydrogen bonds and weak Ag-O interactions.     

Ruthenium (II) complexes of the chelating phosphine borane H2ClB · dppm

Reaction of H₂ClB · PPh₂CH₂PPh₂ (H₂ClB · dppm) with results in displacement of all three acetonitrile ligands and the formation of (1), which has been characterised crystallographically. Reaction with carbon monoxide results in a change from η² to η¹ of the borane ligand to afford (2). Compound 1 undergoes H/D exchange under a D₂ atmosphere to afford , while 2 does not.     

[Zn(H2PO4)4] clusters and ∞[Zn2(HPO4)3(H2PO4)2] layers in two new zinc phosphates templated by [H2(4-amino-2.2.6.6-tetramethylpiperidine)] cations

Two zinc phosphates (ZnPO), [H₂(N₂C₉H₂₀)]·[Zn(H₂PO₄)₄] (I) and [H₂(N₂C₉H₂₀)]₂·[Zn₂(HPO₄)₃(H₂PO₄)₂]·H₂O (II), are synthesized under hydrothermal conditions using 4-amino-2.2.6.6-tetramethylpiperidine as organic template. I crystallizes in space group with , , , α=92.57(1)°, β=89.76(1)°, γ=102.16(2)°, and Z=2. Its structure, refined to R=0.029 and R_w=0.076 for 4279 independent reflections, consists of [Zn(H₂PO₄)₄]²⁻ clusters held together through strong hydrogen bonds to form pseudo-layers between which the doubly protonated amine molecules are inserted. II is monoclinic, C2, with , , , β=103.72(5)°, and Z=4 (R=0.079, R_w=0.268, 2477 independent reflections). The structure of II consists of _∞[Zn₂(HPO₄)₃(H₂PO₄)₂]⁴⁻ inorganic (2D) layers built up from vertex-sharing [ZnO₄] and [(H₂/H)PO₄] tetrahedra. Organic cations and water molecules ensure the connection between these layers via hydrogen bonds. It is shown that numerous (1D), (2D), e.g., [H₂(N₂C₉H₂₀)]₂·[Zn₂(HPO₄)₃(H₂PO₄)₂]·H₂O, and (3D) (ZnPO) result from the condensation of the [Zn(H₂PO₄)₄]²⁻ clusters.     

Synthesis and crystal structure of the isotypic rare earth thioborates Ce[BS3], Pr[BS3], and Nd[BS3]

The orthothioborates Ce[BS₃], Pr[BS₃] and Nd[BS₃] were prepared from mixtures of the rare earth (RE) metals together with amorphous boron and sulfur summing up to the compositions CeB₃S₆, PrB₅S₉ and NdB₃S₆. The following preparation routes were used: solid state reactions with maximum temperatures of 1323 K and high-pressure high-temperature syntheses at 1173 K and 3 GPa. Pr[BS₃] and Nd[BS₃] were also obtained from rare earth chlorides RECl₃ and sodium thioborate Na₂B₂S₅ by metathesis type reactions at maximum temperatures of 1073 K. The crystal structure of the title compounds was determined from X-ray powder diffraction data. The thioborates are isotypic and crystallize in the orthorhombic spacegroup Pna2₁ (No. 33; Z=4; Ce: , , ; Pr: , , ; Nd: , , ) . The crystal structures contain isolated [BS₃]^3‐ groups with boron in trigonal-planar coordination. The sulfur atoms form the vertices of undulated kagome nets, which are stacked along [100] according to the sequence ABAB. Within these nets every second triangle is occupied by boron and the large hexagons are centered by rare earth ions, which are surrounded by overall nine sulfur species.     

A novel organically templated three-dimensional open framework vanadium tellurite: (NH3CH2CH2NH3)2V2Te6O18

A novel organically templated vanadium tellurite (NH₃CH₂CH₂NH₃)₂V₂Te₆O₁₈ (1) has been hydrothermally synthesized and characterized by elemental analyses, IR, thermal stability analysis, magnetic susceptibilities and single crystal X-ray diffraction. Compound 1 crystallizes in the monoclinic system, space group P2₁/n, , , , β=94.789(4)°, , Z=2, R₁[I>2σ(I)]=0.0187, wR₂[I>2σ(I)]=0.0482. Compound 1 exhibits a novel three-dimensional (3D) vanadium tellurite anion framework composed of vanadium, tellurium, and oxygen atoms through covalent bonds, with the [NH₃CH₂CH₂NH₃]²⁺ cations residing in the channels.