Two fumarato-bridged Co(II) coordination polymers: syntheses,crystal structures and properties of Co(H2O)4L and [Co3(H2O)4(OH)2L2]·2H2O with H2LHOOCCHCHCOOH

Two fumarato-bridged Co(II) coordination polymers Co(H₂O)₄L 1 and [Co₃(H₂O)₄(OH)₂L₂]·2H₂O 2 with H₂LHOOCCH CHCOOH were prepared. Complex 1 consists of polymeric chains _∞¹[Co(H₂O)₄(C₄H₂O₄)_2/2], which result from octahedrally coordinated Co atoms bridged by bis-monodentate fumarate anions and are assembled by interchain hydrogen bonds. Within 2, the edge-shared Co₂O₁₀ bi-octahedra are connected to the CoO₆ octahedra to form 1D cobalt oxide chains and 3D open framework generated from the chains inter-linked by bis-bidentate fumarate anions displays rhombic tunnels, which are filled with the lattice H₂O molecules. Thermal and magnetic behaviors of both the title coordination polymers are discussed. Crystal data: (1) monoclinic, P2₁/c, Z=4, a=7.493(1) Å, b=14.377(1) Å, c=7.708(1) Å, β=99.54(1)°, V=818.9(2) Å³, R₁=0.0304, and wR₂=0.0669 for 1487 observed reflections (I⩾2σ(I)) out of 1877 unique reflections; (2) monoclinic, P2₁/c, Z=2, a=6.618(1) Å, b=8.172(2) Å, c=15.578(3) Å, β=96.30(3)°, V=837.4(3) Å³, R₁=0.0360 and wR₂=0.0663 for 1442 observed reflections (I⩾2σ(I)) out of 1927 unique reflections.     

Synthesis and structure of the novel anion [AsMo6O15(OH)3(SO4)3]6–, first example of a reduced molybdo-sulphate cluster

A novel anion derived from the Anderson structure has been obtained in aqueous acid solution by condensation of three pairs of edge-sharing molybdenum octahedra around a central arsenite. This association forms a hexanuclear ring of Mo(V) with three external sulphate groups bridging the binuclear molybdenum units. This compound crystallizes in the presence of alkaline ions and its orthorhombic structure was solved by single crystal X-ray diffraction [Cmca, a=24.3189(3) Å, b=12.4454(1) Å, c=26.9211(3) Å, V=8 147,9 ų] from 4 277 unique reflections [I≥2 σ(I)], R₁=0.0471 and _wR₂=0.1429. The solid is a three-dimensional network built up from cluster anions strongly connected to alkaline ions via ionic links. This soluble compound, presenting labile peripheral sulphates, is predisposed for exchanges to build new anions. © 2000 Académie des sciences / Éditions scientifiques et médicales Elsevier SASpolyoxometalate / sulphate / reduced cluster / arsenite / molybdenum     

Hybrid inorganic–organic frameworks containing magnesium: Synthesis and structures of magnesium squarate,diglycolate, and glutarate,and potassium magnesium cyclobutanetetracarboxylate

Four new magnesium containing metal–organic hybrid compounds have been synthesized in an effort to prepare low-density materials for hydrogen storage. The compounds were prepared hydrothermally and characterized using single crystal X-ray diffraction. Three of these compounds are analogs of known transition metal structures with squarate (I, Pn-3n, a = 16.276(5) Å), diglycolate (II, P2₁2₁2₁, a = 6.860(1) Å, b = 9.993(1) Å, c = 10.884(1) Å, R₁ = 0.0341), and glutarate (III, R-3, a = 10.744(2) Å, c = 28.677(5) Å, R₁ = 0.0554) ligands; the fourth is a novel structure using cyclobutanetetracarboxylate (IV, Pccn, a = 9.382(1) Å, b = 14.410(2) Å, c = 8.725(1) Å, R₁ = 0.0465) which contains potassium as well as magnesium cations.     

Intercalation of KCl into layered neptunyl and plutonyl iodates

The hydrothermal reaction of Np(IV) or Pu(IV) with KIO₄ and CsCl at 180°C for 1 day results in the formation of NpO₂(IO₃)₂·0.5KCl·3.25H₂O (1) or PuO₂(IO₃)₂·0.5KCl·2.5H₂O (2). The neutral layers in compounds 1 and 2 are isostructural with NpO₂(IO₃)₂·H₂O and PuO₂(IO₃)₂·H₂O, respectively. The Np and Pu centers are found in distorted pentagonal bipyramidal [AnO₇] environments that are formed from the ligation of NpO₂²⁺ or PuO₂²⁺ cations by iodate anions. There are two crystallographically unique pyramidal iodate anions in 1 and 2. One of these anions utilizes all three oxygen atoms to simultaneously bridge three neptunyl or plutonyl units. The second anion only bridges two actinyl units and has a terminal oxo atom. The bridging of the actinyl cations by iodate anions creates neutral _∞²[AnO₂(IO₃)₃] (An=Np, Pu) sheets that are separated by K⁺ cations, Cl⁻ anions, and water molecules. Crystallographic data (203 K, MoKα, λ=0.71073): 1, monoclinic, space group C2/c,a=21.537(5) Å, b=11.670(3) Å, c=7.315(2) Å, β=93.033(4)°, Z=4, R(F)=5.43% for 136 parameters with 1309 reflections with I>2σ(I); 2, monoclinic, space group C2/c, a=21.570(4) Å, b=11.656(2) Å, c=7.348(2) Å, β=94.00(3), Z=4, R(F)=4.92% for 148 parameters with 1317 reflections with I>2σ(I).     

Spectroscopic studies and crystal structure of tetrabutylammonium trichlorodimethylstannate(IV): Bu4NSnMe2Cl3

The structure of Bu₄NSnMe₂Cl₃ is found to be monomer, containing a 5-coordinated bipyramidal trigonal tin(IV) center. Crystals belong to the monoclinic space group C2/c, with unit-cell dimensions a = 26.633(4) Å; b = 9.880(2) Å; c = 21.510(2) Å; β = 114.82(2)°; Z = 8; D = 1.287 Mg/m³; R is refined to 0.0537 and R_w = 0.0642 for 3330 reflections (F > 2σ(F)).     

Ce(H2O)(PO4)3/2(H3O)1/2(H2O)1/2, a second entry in the structural chemistry of cerium(IV) phosphates

A cerium(IV) phosphate has been prepared using precipitation methods and its structure has been solved by single crystal X-ray diffraction (R₁ = 0.0292 for 3092 reflections with I>2σ(I) and wR₂ = 0.0540). Ce(H₂O)(PO₄)_3/2(H₃O)_1/2(H₂O)_1/2 crystallises in the monoclinic space group C2/c (a = 15.7058(17) Å, b = 9.6261(9) Å, c = 10.1632(4) Å, ß = 121.623(7)°, and V = 1308.4 (2) Å³). Its structure is based on a negatively charged 3D framework, made of cerium atoms connected by PO₄ tetrahedra. There are two types of PO₄ units; one shares only corners with the cerium coordination polyhedra while the other one shares edges and corners. This structure also includes hydronium cations, to balance the framework charge, and water molecules. One special feature of this 3D framework is the formation of interconnected tunnels which extend along the c axis and contain the hydronium cations and the water molecules. This open framework and the presence of cationic species in the tunnels are in perfect agreement with the previously reported ion exchange properties.     

Synthesis of open-framework iron phosphates, [C5N2H14]2[FeIII2F2(HPO4)4]·2H2O and [C5N2H14][FeIII4(H2O)4F2(PO4)4], with one- and three-dimensional structures

The hydrothermal syntheses and structures of two new open-framework iron phosphates, [C₅N₂H₁₄]₂[Fe^III₂F₂(HPO₄)₄]·2H₂O, I, and [C₅N₂H₁₄][Fe^III₄(H₂O)₄F₂(PO₄)₄], II, are presented. While the structure of I consist of FeO₄F₂ octahedra and HPO₄ terahedra linked to form one-dimensional structure, that of II consist of FeO₄(H₂O)₂, FeO₄(H₂O)F, FeO₄F₂ and PO₄ units connected to give rise to a three-dimensional structure. The structure of I resembles the naturally occurring mineral tancoite while II resembles the iron phosphate, ULM-12, [C₆N₂H₁₄][Fe₄(PO₄)₂F₂(H₂O)₃]. Magnetic susceptibility studies indicate anti-ferromagnetic behavior in both the compounds with T_N=200 and 175 K for I and II, respectively. Crystal data: I, monoclinic, space group=P2₁/n (no. 14). a=7.2261(6), b=16.5731(14), c=11.0847(10) Å, β=97.265(2)°, V=1316.8(2) Å³, Z=4, ρ_calc=1.952 g cm⁻¹, μ_(MoKα)=1.446 mm⁻¹, R₁=0.0448 and wR₂=0.1141 for 1882 data [I>2σ(I)]; for II, monoclinic, space group=P2₁/n (no. 14). a=9.9691(3), b=12.4013(3), c=17.3410(3) Å, β=103.762(1)°, V=2082.32(9) Å³, Z=4, ρ_calc=2.576 g cm⁻¹, μ_(MoKα)=3.162 mm⁻¹, R₁=0.0510 and wR₂=0.1064 for 2979 data [I>2σ(I)].     

The crystal structure of potassium ammonium hexamolybdotellurate with telluric acid K5NH4[TeMo6O24].Te(OH)6.6H2O

An inorganic compound formulated as K₅NH₄[TeMo₆O₂₄].Te(OH)₆.6H₂O (1) has been isolated by conventional solution method and structurally characterized by single-crystal X-ray diffraction methods, scanning electron microscopy (SEM), IR, UV–vis spectra, and cyclic voltammetry measurements. This compound crystallizes in the monoclinic system, space group C2/c with unit a = 18.6841(1) Å, b = 10.0513(1) Å, c = 21.1065(1) Å, β = 116.495(1)°, V = 3547.49(4) ų, Z = 4, R = 0.033 and wR (F²) = 0.087 for 3432 unique observed reflexions [I > 2σ(I)]. The crystal structure of (1) is built up from an Anderson clusters connected through hydrogen-bonding interactions into a three-dimensional supramolecular network.     

Synthesis,crystal structure and thermal behaviour of [La(hfa)3(Phen)2] (hfa = hexafluoroacetylacetonate,Phen = o-phenanthroline)

The mixed ligand complex [La(hfa)₃(Phen)₂] (I) was obtained by the interaction of La(hfa)₃ and Phen; its composition does not depend on the stoichiometry of the reagents. According to the X-ray single crystal analysis data, complex I crystallizes in the monoclinic space group P2₁/n, with a = 13.583(3) Å, b = 16.959(3) Å, c = 18.860(4) Å, β = 94.71(3)° and Z = 4. The structure of I consists of isolated mononuclear molecules, the coordination number of La being 10. Thermal behaviour and composition of the vapor phase have been studied for I by thermal analysis and mass-spectrometry using a Knudsen cell. The mixed ligand complex I was found to sublime congruently in the temperature range 370–460 K: [La(hfa)₃(Phen)₂]_(s) = [La(hfa)₃(Phen)]_(g) + Phen_(g), Δ_rH⁰(T) = 316.2 ± 1.8 kJ/mol.     

Crystal structure of Pb2SbS2I3, and re-examination of the crystal chemistry within the group of (Pb/Sn/Sb) chalcogeno-iodides

The crystal structure of Pb₂SbS₂I₃ was solved at room temperature and 100 K. At 293 K it crystallizes in the orthorhombic system, space group Cmcm (No. 63), with unit cell parameters a = 4.3262(9), b = 14.181(3), c = 16.556(3) Å, V = 1017.7(4) Å³, Z = 4. The structure is disordered, and combines a split Pb site (s.o.f. = 0.50) with one mixed (Pb,Sb) site with Pb and Sb in two distinct sub-positions. At 100 K, it is monoclinic, space group P2₁/c, with unit cell parameters a = 7.3629(6), b = 16.466(3), c = 8.5939(7) Å, β = 107.14(2)°, V = 995.6(2) Å³, Z = 4. The structure is now fully ordered, without mixed sites. On the basis of bond valence calculations, new cation distributions are proposed for published structures of the Sn isotypes, Sn₂SbS₂I₃ and Sn₂SbSe₂I₃. A re-examination of the crystal structures of various (Pb/Sn/Sb) chalcogeno-iodides is presented according to modular analysis. All these structures can be described according to three types of 1D modules, (Pb/Sn)I₄, (Sn)₂I₄ and (Pb/Sn/Sb)₄(S/Se)₂I₄. Generally each type of 1D module gives one type of slab, and the final structure corresponds to a specific stacking of two or three among these slabs. A new structural model is proposed for “α-Sn₂SI₂”, which would have the non-stoichiometric composition (Sn_5.42□_0.58)S₂(I_6.87□_0.12), ideally Sn₂₇S₁₀I₃₄, with probably a narrow solid solution field on the SnS–SnI₂ joint.     

Hydrothermal synthesis and structure determination of Ag3(VVO2){O3PCH2PO3} or MIL-42: a new vanadium(V) methylendiphosphonate inserting silver cations

A new formulated compound, Ag₃(V^VO₂){O₃PCH₂PO₃} or MIL-42, was synthesized hydrothermally at 170 °C. It crystallizes in the monoclinic system (space group P2₁/n (n°14)) with lattice parameters a=8.9404(2) Å, b=8.0226(2) Å, c=11.7395(1) Å and β=100.720(1)°, V=827.32(3) ų, Z=4. Its structure was determined from single crystal X-ray diffraction data (R₁(F_o)=0.0231, wR₂(F_o²)=0.0588 for 2126 unique reflections with I≥2σ(I)). MIL-42 is three-dimensional with one-dimensional chains of corner linked trimeric units related by sheets of Ag⁺ in tetrahedral and five-fold coordination. The chains are built up from V^VO₅ trigonal bipyramids; one edge of their equatorial plane is chelated by one methylendiphosphonate group. The silver sheets are built up from corner-sharing hexamers in which silver exhibits tetrahedral and five-fold coordination.     

Single crystal structure and magnetic properties of a new quaternary samarium-titanium oxyselenide: Sm3Ti3Se2O8

The new compound Sm₃Ti₃Se₂O₈ has been synthesized by a solid state reaction of Sm₂O₃, TiO₂, and TiSe₂ at T=1000 °C. This compound crystallizes in the monoclinic symmetry, space group P2₁/m (No. 11), with unit cell parameters: a=9.7844(6), b=3.8865(5), c=13.330(1) Å, and β=111.37(1)°, Z=2. Its crystal structure can be roughly described as small fragments [SmSe] of a rock-salt-type structure interconnected by a complex entity built up from the condensation of edge sharing [TiO] octahedra. Refinement for 1019 independent reflections and 73 variables converged to the reliability factor R_F=2.00 % (for 942 reflections satisfying the criterion I≥3σ(I)). Magnetic susceptibility of the title compound has been measured from 2 to 300 K and has shown a paramagnetic behavior of the van Vleck Sm³⁺ cation in the whole temperature range.     

Controlling the dimensionality of oxalate-based bimetallic complexes: The ferromagnetic chain {[K(18-crown-6)][Mn(bpy)Cr(ox)3]}∞(18-crown-6 = C12H24O6, ox=C2O42-, bpy = C10H8N2)

The bimetallic ferromagnetic chain {[K(18-crown-6)][Mn(bpy)Cr(ox)₃]}_∞ (1) has been synthesized and characterized. It crystallizes in the orthorhombic chiral space group P2₁2₁2₁ [a = 9.0510(2) Å, b = 14.4710(3) Å, c = 26.8660(8) Å, V = 3510.97(1) Å³, Z = 2]. Compound 1 is made up by anionic [Mn(bpy)Cr(ox)₃]⁻ 1D chains and cationic [K(18-crown-6)]⁺ complexes. The magnetic exchange within the chain is ferromagnetic [J = +7.8(7) cm⁻¹]. In the solid state, the ferromagnetic chains are well isolated magnetically and no long range magnetic ordering has been observed above 2 K.     

Synthesis and crystal structure of the first chain-type nitridosilicates RE5Si3N9 (RE = La,Ce)

The novel branched chain-type nitridosilicates Ce₅Si₃N₉ and La₅Si₃N₉ have been synthesized in a radio-frequency furnace starting from the respective metals and silicon diimide Si(NH)₂ at 1625 °C for La₅Si₃N₉ and 1650 °C for Ce₅Si₃N₉, respectively. The structure of Ce₅Si₃N₉ has been determined by single-crystal X-ray diffraction (Ce₅Si₃N₉, Cmca (no. 64), a = 10.567(2) Å, b = 11.329(2) Å, c = 15.865(3) Å, V = 1899.3 Å³, Z = 8, R₁ = 0.0391, 1480 independent reflections, 90 refined parameters). The structure of isotypic La₅Si₃N₉ has been refined by the Rietveld method, starting from single-crystal data of Ce₅Si₃N₉ (La₅Si₃N₉, Cmca (no. 64), a = 10.647(4) Å, b = 11.414(4) Å, c = 16.030(5) Å, V = 1948.1 Å³, Z = 8, R_P = 0.0348, R_F² = 0.0533). Both compounds are built up of alternating Q²- and Q³-type corner sharing SiN₄ tetrahedra with additional corner sharing Q¹-units attached to the Q³-tetrahedra pointing alternately in opposing directions. These zipper-like chains are intertwined in both directions perpendicular to the chain itself to form a three-dimensionally interlocked structure with the rare-earth ions situated between the chains. Magnetic measurements resulted in a ferromagnetic ground state with a magnetic moment in agreement with Ce³⁺.     

Copper diazine spin ladders: Synthesis,structure and magnetic analyses of Cu(2-methylthiopyrazine)Br2

The reaction of copper(II) bromide with 2-methylthiopyrazine (meSpz) in THF/CH₂Cl₂ gave crystals of [Cu(meSpz)Br₂]_n. The compound crystallizes in the monoclinic space group C2/m: a = 13.754(6) Å, b = 6.825(2) Å, c = 9.731(4) Å, β = 104.598(8)°. The structure comprises ladders where the rungs of the ladder are formed by bridging bromide ions and the rails are formed by bridging meSpz molecules. Magnetic susceptibility data over the range 1.8–325 K was fit to a strong-rung ladder model resulting in J/k_rung = ?39.79(17) K and J/k_rail = ?18.0(4) K.     

Subsolidus phase relations,crystal chemistry and cation-transport properties of sodium iron antimony oxides

Subsolidus phase relations in Na₂O–Fe₂O₃–Sb₂O_x system (excluding Na-rich and Sb-rich corners) were studied using powder X-ray diffraction. Samples were prepared by conventional solid-state reactions at 980–1030 °C followed by quenching. Sb substitution for Fe stabilizes the low-temperature rhombohedral α form of NaFeO₂ and enhances ionic conductivity: σ(300 °C) = 0.5 S/m, E_a = 0.38(3) eV, t_e < 0.01 for Na_0.8Fe_0.9Sb_0.1O₂ ceramics. Besides known orthorhombic Na₂Fe₃SbO₈, three new compounds have been identified: trigonal Na₄FeSbO₆, a superlattice of α-NaFeO₂ type, a = 5.4217(7) Å, c = 16.2715(1) Å, possible space group P3₁12; orthorhombic Na₂FeSbO₅, possibly related to brownmillerite, Pbcn, a = 10.8965(13) Å, b = 15.7178(13) Å, c = 5.3253(4) Å, and one more phase with empirical formula Na₄Fe₃SbO₉, whose pattern could not be indexed. Ion-exchange reactions lead to a delafossite-type superlattice Ag₃(NaFeSb)O₆ (a = 5.4503(12) Å, c = 18.7747(20) Å, possible space group P3₁12).     

Synthesis,structure and NMR characterization of a new monomeric aluminophosphate [dl-Co(en)3]2[Al(HPO4)2(H1.5PO4)2(H2PO4)2](H3PO4)4 containing four different types of monophosphates

A new zero-dimensional (0D) aluminophosphate monomer [dl-Co(en)₃]₂[Al(HPO₄)₂(H_1.5PO₄)₂(H₂PO₄)₂](H₃PO₄)₄ (designated AlPO-CJ38) with Al/P ratio of 1/6 has been solvothermally prepared by using racemic cobalt complex dl-Co(en)₃Cl₃ as the template. The Al atom is octahedrally linked to six P atoms via bridging oxygen atoms, forming a unique [Al(HPO₄)₂(H_1.5PO₄)₂(H₂PO₄)₂]^6? monomer. Notably, there exists intramolecular symmetrical O?H?O bonds, which results in pseudo-4-rings stabilized by the strong H-bonding interactions. The structure is also featured by the existence of four different types of monophosphates that have been confirmed by ³¹P NMR and ¹H NMR spectra. The crystal data are as follows: AlPO-CJ38, [dl-Co(en)₃]₂[Al(HPO₄)₂(H_1.5PO₄)₂(H₂PO₄)₂](H₃PO₄)₄, M = 1476.33, monoclinic, C2/c (No. 15), a = 36.028(7) Å, b = 8.9877(18) Å, c = 16.006(3) Å, β = 100.68(3)°, U = 5093.2(18) Å³_, Z = 4, R₁ = 0.0509 (I > 2σ(I)) and wR₂ = 0.1074 (all data). CCDC number 689491.     

A new intersecting tunnel structure in the AIMIII[PO3(OH)]2 series for AI = Ag,MIII = In: Analysis of structural relationships

A new indium hydroxyphosphate containing silver, AgIn[PO₃(OH)]₂, has been synthesized using hydrothermal method. It crystallizes in the P2₁/c space group with the cell parameters a = 6.6400(2) Å, b = 14.6269(6) Å, c = 6.6616(4) Å, β = 95.681(5)°, V = 643.82(6) Å³, Z = 4. Its three-dimensional framework, built up of corner-sharing PO₃(OH) tetrahedra and InO₆ octahedra, presents intersecting tunnels running along <111> and [100] directions, in which the Ag⁺ cations are located. The presence of hydroxyl groups has been confirmed from IR spectroscopy studies and hydrogen atoms were located from the single crystal X-ray diffraction study. The structural relationships with the other compounds of general formula A^IM^III[PO₃(OH)]₂ are analyzed.