Combinatorial topology of uranyl molybdate sheets: syntheses and crystal structures of (C6H14N2)3[(UO2)5(MoO4)8](H2O)4 and (C2H10N2)[(UO2)(MoO4)2]

Two new mixed organic-inorganic uranyl molybdates, (C₆H₁₄N₂)₃[(UO₂)₅(MoO₄)₈](H₂O)₄ (1) and (C₂H₁₀N₂)[(UO₂)(MoO₄)₂] (2), have been obtained by hydrothermal methods. The structure of 1 [triclinic, , Z=1, a=11.8557(9), b=11.8702(9), c=12.6746(9) Å, α=96.734(2)°, β=91.107(2)°, γ=110.193(2)°, V=1659.1(2) Å] has been solved by direct methods and refined on the basis of F² for all unique reflections to R1=0.058, which was calculated for the 5642 unique observed reflections (|F_o|?4σ_F). The structure contains topologically novel sheets of uranyl square bipyramids, uranyl pentagonal bipyramids, and MoO₄ tetrahedra, with composition [(UO₂)₅(MoO₄)₈]⁶⁻, that are parallel to (−101). H₂O groups and 1,4-diazabicyclo [2.2.2]-octane (DABCO) molecules are located in the interlayer, where they provide linkage of the sheets. The structure of 2 [triclinic, , Z=2, a=8.4004(4), b=11.2600(5), c=13.1239(6) Å, α=86.112(1)°, β=86.434(1)°, γ=76.544(1)°, V=1203.14(10) Å] has been solved by direct methods and refined on the basis of F² for all unique reflections to R1=0.043, which was calculated for 5491 unique observed reflections (|F_o|?4σ_F). The structure contains topologically novel sheets of uranyl pentagonal bipyramids and MoO₄ tetrahedra, with composition [(UO₂)(MoO₄)₂]²⁻, that are parallel to (110). Ethylenediamine molecules are located in the interlayer, where they provide linkage of the sheets. All known topologies of uranyl molybdate sheets of corner-sharing U and Mo polyhedra can be described by their nodal representations (representations as graphs in which U and Mo polyhedra are given as black and white vertices, respectively). Each topology can be derived from a simple black-and-white graph of six-connected black vertices and three-connected white vertices by deleting some of its segments and white vertices.     

[C4N2H12]1.5[Zn2(PO4)(HPO4)2]·H2O晶体的合成与表征

由于在电学、磁学、光学、吸附、离子交换和催化等领域具有潜在的应用价值,具有开放骨架结构的金属磷酸盐的合成一直受到人们的广泛关注.在这些磷酸盐微孔化合物中,磷酸锌晶体是拓扑结构最为丰富的一种.     

Hydrothermal synthesis and characterization of layered vanadium phosphite: [HN(C2H4)3N][(VO)2(HPO3)2(OH)(H2O)]·H2O

A novel compound, [HN(C₂H₄)₃N][(VO)₂(HPO₃)₂(OH)(H₂O)]·H₂O, was hydrothermally synthesized and characterized by single crystal X-ray diffraction. This compound crystallizes in the monoclinic system with the space group C2/c and cell parameters a=11.0753(3) Å, b=17.8265(6) Å, c=16.5229(5) Å, and β=92.362(2)°. The structure of the compound consists of vanadium phosphite layers which are built up from the infinite one-dimensional chains of [(VO)(H₂O)(HPO₃)₂]²⁻ of octahedral VO₅(H₂O) and pseudo pyramidal [HPO₃], and bridging binuclear fragments of [VO(OH)]₂. Thermogravimetric analysis and magnetic susceptibility data for this compound are given.     

New open-framework in the uranyl vanadates A3(UO2)7(VO4)5O (A=Li, Ag) with intergrowth structure between A(UO2)4(VO4)3 and A2(UO2)3(VO4)2O

New uranyl vanadates A₃(UO₂)₇(VO₄)₅O (M=Li (1), Na (2), Ag (3)) have been synthesized by solid-state reaction and their structures determined from single-crystal X-ray diffraction data for 1 and 3. The tetragonal structure results of an alternation of two types of sheets denoted S for _∞²[UO₂(VO₄)₂]⁴⁻ and D for _∞²[(UO₂)₂(VO₄)₃]⁵⁻ built from UO₆ square bipyramids and connected through VO₄ tetrahedra to _∞¹[U(3)O₅-U(4)O₅]⁸⁻ infinite chains of edge-shared U(3)O₇ and U(4)O₇ pentagonal bipyramids alternatively parallel to a- and b-axis to construct a three-dimensional uranyl vanadate arrangement. It is noticeable that similar _∞[UO₅]⁴⁻ chains are connected only by S-type sheets in A₂(UO₂)₃(VO₄)₂O and by D-type sheets in A(UO₂)₄(VO₄)₃, thus A₃(UO₂)₇(VO₄)₅O appears as an intergrowth structure between the two previously reported series. The mobility of the monovalent ion in the mutually perpendicular channels created in the three-dimensional arrangement is correlated to the occupation rate of the sites and by the geometry of the different sites occupied by either Na, Ag or Li. Crystallographic data: 293 K, Bruker X8-APEX2 X-ray diffractometer equipped with a 4 K CCD detector, MoKα, λ=0.71073 Å, tetragonal symmetry, space group P4¯m2, Z=1, full-matrix least-squares refinement on the basis of F²; 1,a=7.2794(9) Å, c=14.514(4) Å, R1=0.021 and wR2=0.048 for 62 parameters with 782 independent reflections with I?2σ(I); 3, a=7.2373(3) Å, c=14.7973(15) Å, R1=0.041 and wR2=0.085 for 60 parameters with 1066 independent reflections with I?2σ(I).     

Na(H3NCH2CH2NH3)0.5[Co(C2O4)(HPO4)]: A novel phosphoxalate open-framework compound incorporating both an alkali cation and an organic template in the structural tunnels

The first open-framework metal phosphoxalate compound containing both an organic and an inorganic template in the same structure is reported. Na(H₃N⁺CH₂CH₂N⁺H₃)_0.5[Co(C₂O₄)(HPO₄)] (1) was synthesized hydrothermally via a direct metathesis reaction using the sodium salts of oxalate and phosphate in the presence of cobalt chloride and ethylenediamine dihydrochloride. The structure of 1 consists of a 3D framework built from the [Co(C₂O₄)]_n layers connected by HPO₄²⁻ group bridging two different cobalt centers between the adjacent layers. A major and a minor structural tunnels are created and occupied by the Na⁺ and H₃N⁺CH₂CH₂NH₃²⁺ ions, respectively, in the same structure. Single-crystal X-ray crystallographic data for 1 are: monoclinic, P2₁/c, a=5.8189(6), b=10.235(1), c=13.066(1) Å, β=96.671(2)°, Z=4, V=772.9(1) Å³, R=3.95% and R_w=6.37%.     

Hydrothermal synthesis, crystal structure, and characterization of a new pseudo-two-dimensional uranyl oxyfluoride, [N(C2H5)4]2[(UO2)4(OH2)3F10]

A new uranyl oxyfluoride, [N(C₂H₅)₄]₂[(UO₂)₄(OH₂)₃F₁₀] has been synthesized by a hydrothermal reaction technique using (C₂H₅)₄NBr, UO₂(OCOCH₃)₂·2H₂O, and HF as reagents. The structure of [N(C₂H₅)₄]₂[(UO₂)₄(OH₂)₃F₁₀] has been determined by a single-crystal X-ray diffraction technique. [N(C₂H₅)₄]₂[(UO₂)₄(OH₂)₃F₁₀] crystallizes in the monoclinic space group P2₁/n (No. 14), with , , , β=98.88(3)°, , and Z=4. [N(C₂H₅)₄]₂[(UO₂)₄(OH₂)₃F₁₀] reveals a novel pseudo-two-dimensional crystal structure that is composed of UO₂F₅, UO₃F₄, and UO₄F₃ pentagonal bipyramids. Each uranyl pentagonal bipyramid shares edges and corners through F atoms to form a six-membered ring. The rings are further interconnected to generate infinite strips running along the b-axis. [N(C₂H₅)₄]₂[(UO₂)₄(OH₂)₃F₁₀] has been further characterized by elemental analysis, bond valence calculations, Infrared and Raman spectroscopy, and thermogravimetric analysis.     

An open-framework three-dimensional indium oxalate: [In(OH)(C2O4)(H2O)]3·H2O

By hydrothermal reaction of In₂O₃ with H₂C₂O₄·2H₂O in the presence of H₃BO₃ at 155 °C, an open-framework three-dimensional indium oxalate of formula [In(OH)(C₂O₄)(H₂O)]₃·H₂O (1) has been obtained. The compound crystallizes in the trigonal system, space group R3c with , , , Z=6, R₁=0.0352 at 298 K. The small pores in 1 are filled with water molecules. It loses its filled water at about 180 °C without the change of structure, then the bounded water at 260 °C, and completely decompounds at 324 °C. The residue is confirmed to be In₂O₃.     

[C2N2H10]1.5[Nd(SO4)3(H2O)]·2H2O: The first organically templated neodymium sulfate with a layer structure

The first organically templated neodymium sulfate has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction analysis. [C₂N₂H₁₀]_1.5[Nd(SO₄)₃(H₂O)]·2H₂O crystallizes in the monoclinic space group P2₁/c with crystal data , , , β=104.399(5)°, , Z=4. Refinement gave R₁[I>2σ(I)]=0.0471, and wR₂[I>2σ(I)]=0.0899. The compound exhibits an infinite zigzag anionic layer structure, which consists of {Nd(SO₄)₃(H₂O)}³⁻ structural units connected together to form interesting eight-membered rings via corner-sharing and edge-sharing modes. The compound has the antiferromagnetic behavior and exhibits intense photoluminescence upon photo-excitation at 450 nm.     

One-dimensional chains in uranyl tungstates: Syntheses and structures of A8[(UO2)4(WO4)4(WO5)2] (A=Rb, Cs) and Rb6[(UO2)2O(WO4)4]

Three new uranyl tungstates, A₈[(UO₂)₄(WO₄)₄(WO₅)₂] (A=Rb (1), Cs (2)), and Rb₆[(UO₂)₂O(WO₄)₄] (3), were prepared by high-temperature solid-state reactions and their structures were solved by direct methods on twinned crystals, refined to R₁=0.050, 0.042, and 0.052 for 1, 2, and 3, respectively. Compounds 1 and 2 are isostructural, monoclinic P2₁/n, (1): a=11.100(7), b=13.161(9), , β=90.033(13)°, , Z=8 and (2): , , , β=89.988(2)°, , Z=8. There are four symmetrically independent U⁶⁺ sites that form linear uranyl [O=U=O]²⁺ cations with rather distorted coordination in their equatorial planes. There are six W positions: W(1) and W(2) have square-pyramidal coordination (WO₅), whereas W(3), W(4), W(5), and W(6) are tetrahedrally coordinated. The structures are based upon a novel type of one-dimensional (1D) [(UO₂)₄(WO₄)₄(WO₅)₂]⁴⁻ chains, consisting of WU₄O₂₅ pentamers linked by WO₄ tetrahedra and WO₅ square pyramids. The chains run parallel to the a-axis and are arranged in modulated pseudo-2D-layers parallel to (0 1 0). The A⁺ cations are in the interlayer space between adjacent pseudo-layers and provide a 3D integrity of the structures. Compounds 1 and 2 are the first uranyl tungstates with 2/3 of W atoms in tetrahedral coordination. Such a high concentration of low-coordinated W⁶⁺ cations is probably responsible for the 1D character of the uranyl tungstate units. The compound 3 is triclinic, P1¯ a=10.188(2), b=13.110(2), , α=97.853(3), β=96.573(3), γ=103.894(3)°, , Z=4. There are four U positions in the structure with a typical coordination of a pentagonal bipyramid that contain uranyl ions, UO₂²⁺, as apical axes. Among eight W sites, the W(1), W(2), W(3), W(4), W(5), and W(6) atoms are tetrahedrally coordinated, whereas the W(7) and W(8) cations have distorted fivefold coordination. The structure contains chains of composition [(UO₂)₂O(WO₄)₄]⁶⁻ composed of UO₇ pentagonal bipyramids and W polyhedra. The chains involve dimers of UO₇ pentagonal bipyramids that share common O atoms. The dimers are linked into chains by sharing corners with WO₄ tetrahedra. The chains are parallel to [−101] and are arranged in layers that are parallel to (1 1 1). The Rb⁺ cations provide linkage of the chains into a 3D structure. The compound 1 has many structural and chemical similarities to its molybdate analog, Rb₆[(UO₂)₂O(MoO₄)₄]. However, the compounds are not isostructural. Due to the tendency of the W⁶⁺ cations to have higher-than-fourfold coordination, part of the W sites adopt distorted fivefold coordination, whereas all Mo atoms in the Mo compound are tetrahedrally coordinated. Distribution of the WO₅ configurations along the chain extension does not conform to its ‘typical’ periodicity. As a result, both the chain identity period and the unit-cell volume are doubled in comparison to the Mo analog, which leads to a new structure type.     

New one-dimensional uranyl and neptunyl iodates: crystal structures of K3[(UO2)2(IO3)6](IO3)·H2O and K[NpO2(IO3)3]·1.5H2O

The uranyl and neptunyl(VI) iodates, K₃[(UO₂)₂(IO₃)₆](IO₃)·H₂O (1) and K[NpO₂(IO₃)₃]·1.5H₂O (2), have been prepared and crystallized under mild hydrothermal conditions. The structures of 1 and 2 both contain one-dimensional _∞¹[AnO₂(IO₃)₃]¹⁻(An=U,Np) ribbons that consist of approximately linear actinyl(VI) cations bound by iodate anions to yield AnO₇ pentagonal bipyramids. The AnO₇ units are linked by bridging iodate anions to yield chains that are in turn coupled by additional iodate anions to yield ribbons. The edges of the ribbons are terminated by monodentate iodate anions. For 1 and 2, K⁺ cations and water molecules separate the ribbons from one another. In addition, isolated iodate anions are also found between _∞¹[UO₂(IO₃)₃]¹⁻ ribbons in 1. In order to aid in the assignment of oxidation states in neptunyl containing compounds, a bond-valence sum parameter of 2.018 Å for Np(VI) bound exclusively to oxygen has been developed with b=0.37 Å. Crystallographic data (193 K, MoKα, λ=0.71073): 1, triclinic, , a=7.0609(4) Å, b=14.5686(8)  Å, c=14.7047(8)  Å, α=119.547(1)°, β=95.256(1)°, γ=93.206(1)°, Z=2, R(F)=2.49% for 353 parameters with 6414 reflections with I>2σ(I); (203 K, MoKα, λ=0.71073): 2, monoclinic, P2₁/c, a=7.796(4)  Å, b=7.151(3)  Å, c=21.79(1)  Å, β=97.399(7)°, Z=4, R(F)=6.33% for 183 parameters with 2451 reflections with I>2σ(I).     

[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.     

Hydrothermal synthesis and characterization of a new three-dimensional hybrid zinc phosphate [Zn2(HPO4)2(4,4′-bipy)]·3H2O with neutral porous framework

Employing 4,4′-bipyridine as a bridged ligand, a new three-dimensional (3-D) hybrid zinc phosphate [Zn₂(HPO₄)₂(4,4′-bipy)]·3H₂O has been prepared under hydrothermal conditions and characterized by single crystal X-ray diffraction. This compound crystallizes in the monoclinic space group C2/c, with cell parameters, , , , β=90.21(3)°, and Z=4. The connectivity of the ZnO₃N and HPO₄ tetrahedra results in a 2-D neutral layer that with interesting 4,8² net along the bc plane. Furthermore, the 4,4′-bipyridine molecule links the 4,8² net into a 3-D structure. The water molecules sit in the middle of the channels and interact with the framework via hydrogen bonds. The compound exhibits intense photoluminescence at room temperature.     

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.     

Synthesis and Structure of a New Organic-Inorganic Framework with Tetranuclear Clusters, [Co4(OH)2(H2O)2](C4H11N2)2[C6H2(COO)4]2·3H2O

A new hybrid organic-inorganic three-dimensional compound, [Co₄(OH)₂(H₂O)₂](C₄H₁₁N₂)₂[C₆H₂(CO₂)₄]₂·3H₂O 1, has been synthesized via hydrothermal reactions and characterized by single-crystal X-ray diffraction, infrared spectroscopy, thermogravimetric analysis, and magnetic techniques. Compound 1 crystallizes in the monoclinic space group P2₁/n (no. 14) with a=6.3029(9) Å, b=16.413(2) Å, c=17.139(2) Å, β=98.630(2)°, V=1735.0(4) ų, Z=2. Compound 1 contains tetranuclear Co₄(μ₃-OH)₂(H₂O)₂ clusters that are inter-linked by pyromellitate bridging ligands into a three-dimensional structure containing one-dimensional tunnels along the a-axis with water and pendant monoprotonated piperazine molecules in the center. The variable temperature magnetic susceptibility was measured from 2 to 300 K at 5000 Oe showing a predominantly anti-ferromagnetic interaction in 1, and the field dependence of magnetization was measured at 2, 5, 15, and 20 K indicating the competition of magnetic interactions in the tetranuclear centers.     

Hydrothermal synthesis and characterization of a new 3D vanadium(III) phosphite (C4H8N2H4)0.5(C4H8N2H3)[V4(HPO3)7(H2O)3]1.5H2O

A new vanadium(III) phosphite, (C₄H₈N₂H₄)_0.5(C₄H₈N₂H₃)[V₄(HPO₃)₇(H₂O)₃]1.5H₂O, has been synthesized hydrothermally by using V₂O₅, H₃PO₃ as reactants, piperazine as the structure-directing agent. The as-synthesized product was characterized by powder X-ray diffraction, IR spectroscopy, inductively coupled plasma analysis, thermogravimetric analysis, and SQUID magnetometer. Single-crystal X-ray diffraction analysis shows that the title compound crystallized in the trigonal space group (No. 165) with the parameters: , , and Z=4. Its structure is built up by alternation of octahedral VO₆ or VO₅(H₂O) and pseudo-pyramidal HPO₃ units to form infinite 2D layers, and these layers are interconnected by sharing vertex-oxygen with octahedral VO₆ units to generate a 3D open-framework structure with 12-membered ring channels in a and b directions, respectively, where there exist entrapped diprotonated and mono-protonated piperazine cations, and water molecules. Magnetic measurement indicates that paramagnetic behavior is observed down to 4 K.     

[Co(en)3][In3(H2PO4)6(HPO4)3]·H2O: A new layered indium phosphate templated by cobalt complex

A new layered indium phosphate [Co(en)₃][In₃(H₂PO₄)₆(HPO₄)₃]·H₂O (1) has been synthesized solvothermally by using a racemic mix of chiral metal complex Co(en)₃Cl₃ as a template. Its structure is determined by single-crystal X-ray diffraction analysis and further characterized by X-ray powder diffraction, ICP, NMR and TG analyses. The inorganic layer is built up by alternation of In-centred octahedra (InO₆) and P-centered tetrahedra (PO₃(OH), PO₂(OH)₂, PO₂(=O)(OH) and PO(=O)(OH)₂) forming a 4.12-net. The metal complex cations locate in the interlayer region and interact with the host network through H-bonds. It is the first indium phosphate compound templated by a transition-metal complex and is isostructural with GaPO-CJ14. Crystal data: 1, monoclinic, space group P2₁/m (No. 11), a=9.1700(18) Å, b=22.6923(5) Å, c=9.9116(2) Å, β=107.87(3)°, Z=4, R_1[I>2σ(I)]=0.0287 and wR_{2(all data)}=0.0939.     

[Ni(C6N2H14)2][Zn4(H2O)(HPO3)5]: A new open-framework zinc phosphite with intersecting 8-, 12- and 16-ring channels

A new three-dimensional (3-D) zinc phosphite with Zn/P ratio of 4/5, [Ni(C₆N₂H₁₄)₂][Zn₄(H₂O)(HPO₃)₅] (1), has been prepared by using self-assembled nickel complexes as the structure-directing agents. Its structure is built up from strict alternation of ZnO₄ tetrahedra and HPO₃ pseudo-pyramids, resulting in an open framework with multi-directional intersecting 8-, 12- and 16-ring channels. The unique nickel complexes Ni(DACH)₂ (DACH=1,2-diaminocyclohexane) only involving the cis-DACH acting as ligands are self-assembled under hydrothermal conditions, and act as the structure-directing agents (SDAs) to direct the formation of compound 1. Nickel complexes reside in the channels in a manner that the hydrophobic ends of the cis-DACH molecules exclusively protrude into the 16-ring pores and the amino groups closely interact with the charged inorganic framework through weak H-bonds. The interesting arrangements of nickel complexes imply a feasible approach to the design and synthesis of extra-large pore materials.     

新型一维链状配位聚合物[Cd2(C23H14O6)2(C10H9N3)2(H2O)]n的研究

配位超分子聚合物的设计合成与应用研究一直是配位化学、超分子化学、生物无机化学及材料科学等领域的热点研究课题之一,具有微孔结构的配位聚合物吸引了许多科学家的目光,这不仅因为该类配合物具有新颖的结构,展现出多种诱人的拓扑结构,更主要的 是因为它们在离子交换、催化、磁性材料、光学材料及气体贮存领域的应用潜力[1～3].     

Hydrothermal synthesis and structural characterization of two organically templated zincophosphites with three-dimensional frameworks, (C6H14N2)·[Zn3(HPO3)4] and (C4H12N2)·[Zn3(HPO3)4]

Two organically templated zincophosphites, (C₆H₁₄N₂)·[Zn₃(HPO₃)₄] and (C₄H₁₄N₂)·[Zn₃(HPO₃)₄] have been prepared under hydrothermal conditions and characterized by single-crystal X-ray diffraction. (C₆H₁₄N₂)·[Zn₃(HPO₃)₄] crystallizes in the triclinic space group , with cell parameters, a=9.363(4) Å, b=10.051(4) Å, c=10.051(4) Å, α=85.777(13)°, β=82.091(9)°, and γ=79.783(9)°. (C₄H₁₄N₂)·[Zn₃(HPO₃)₄] crystallizes in the monoclinic space group P2₁/c, with cell parameters, a=9.9512(3) Å, b=10.1508(3) Å, c=17.8105(5) Å, and β=95.6510(10)°. Although the two structures are different, they have the same anionic framework compositions of [Zn₃(HPO₃)₄]²⁻. Their frameworks are built up from strictly alternating ZnO₄ tetrahedra and HPO₃ pseudo pyramids by sharing vertexes. There exist channels with an eight-membered ring window along the a- and c-axis. Powder X-ray diffraction, IR spectroscopy, ³¹P MAS solid-state NMR, thermogravimetric and differential thermal analyses were also carried out.     

Synthesis and Structure of a New Layered Zincophosphate Zn6(PO4)5(HPO4)·C8N5H28·5H2O, Intercalated with Quintuply Protonated Tetraethylenepentamine

A new two-dimensional zinc phosphate Zn₆(PO₄)₅(HPO₄)·C₈N₅H₂₈·5H₂O has been synthesized hydrothermally using tetraethylenepentamine (TEPA) as structure-directing agent and its structure was determined by means of single-crystal X-ray diffraction. The title compound crystallizes in the orthorhombic system, space group Pca2₁ (No.29) with lattice parameters a=18.6286(12) Å, b=8.0804(5) Å, c=22.5019(15) Å, V= 3387.1(4) ų, Z=4, R₁=0.0389 and wR₂=0.0862 [4042 observed reflections with I>2σ(I)]. The structure involves a network of ZnO₄, PO₄, and PO₃(OH) tetrahedra forming macroanionic inorganic layers with eight-membered apertures. The charge compensation is achieved by the quintuply protonated TEPA molecule in interlamellar space, which interact with the inorganic layers via hydrogen bonding.