Syntheses and structures of two low-dimensional beryllium phosphate compounds: [C5H14N2]2[Be3(HPO4)5].H2O and [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5H2O

The first two low-dimensional beryllium phosphates, [C5H14N2]2[Be3(HPO4)5].H2O (BePO-CJ29) and [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5 H2O (BePO-CJ30), have been successfully synthesized under mild hydrothermal/solvothermal conditions. BePO-CJ29 is built up from strict alternation of BeO4 and HPO4 tetrahedra forming a unique one-dimensional double chains with 12-ring apertures. There are pseudo-10-ring apertures enclosed by two double chains through H-bonds. BePO-CJ29 can also be viewed as a pseudo 2-D layered structure stabilized by strong H-bonds. The diprotonated 2-methylpiperazium cations are located at three positions (i.e., inside the 12-ring aperture, inside the pseudo-10-ring aperture, and in the interlayer of the inorganic pseudo-layers. BePO-CJ30 is constructed by the alternation of Be-centered tetrahedra (including BeO4 and HBeO4) and P-centered tetrahedra (including PO4 and HPO4) resulting in a two-dimensional layered structure parallel to the (0 1 1) direction. The complex layer is composed of coupled 4.8 net sheets. The diprotonated 1,6-hexandiamine cations and water molecules reside in the interlayer regions and interact with the inorganic layers through H-bonds. Crystal data are as follows: [C5H14N2]2[Be3(HPO4)5].H2O (BePO-CJ29), triclinic, P1 (No. 2), a = 8.1000(9) A, b = 8.4841(14) A, c = 19.665(2) A, alpha = 89.683(10) degrees, beta = 78.182(8) degrees, gamma = 87.932(9) degrees, V = 1321.9(3) A3, Z = 2, R1 = 0.0523 (I > 2sigma(I)), and wR2 = 0.1643 (all data); [C6H18N2]0.5[Be2(PO4)(HPO4)OH].0.5 H2O (BePO-CJ30), orthorhombic, Pccn (No. 56), a = 26.01(4) A, b = 8.431(12) A, c = 9.598(13) A, V = 2105(5) A3, Z = 8, R1 = 0.0833 (I > 2sigma(I)), and wR2 = 0.2278 (all data).     

Synthesis and characterization of (R-C5H14N2)2[Ga4(C2O4)(H2PO4)2(PO4)4].2H2O, a layered gallium phosphatooxalate containing a chiral amine

The first metal phosphatooxalate containing a chiral amine, (R-C5H14N2)2[Ga4(C2O4)(H2PO4)2(PO4)4].2H2O, has been synthesized hydrothermally and characterized by single-crystal X-ray diffraction and 31P MAS NMR spectroscopy. It crystallizes in the monoclinic space group P2(1) (No. 4) with a = 8.0248(4) A, b = 25.955(1) A, c = 9.0127(5) A, beta = 100.151(1) degrees, and Z = 2. The structure consists of GaO6 octahedra and GaO4 tetrahedra connected by coordinating C2O4(2-) and phosphate anions to form anionic sheets in the ac plane with charge-compensating diprotonated R-2-methylpiperazinium cations and water molecules between the layers. There is a good correlation between the NMR spectrum and the structure.     

二维层状磷酸亚磷酸钒(Ⅳ)化合物[V2O2(OH)(HPO3)(HPO3)0.7(PO3OH)0.3].(C6N2H16)0.5的水热合成与结构表征

迄今, 在中温水热条件下已合成了大量具有空旷骨架结构的过渡金属磷酸盐微孔材料[1], 这类材料在非线性光学材料、磁性材料、超导材料及催化等诸多方面具有潜在的应用前景[2～5].     

Synthesis,crystal structure,and solid state NMR spectroscopy of NH(4)[(V(2)O(3))(2)(4,4'-bpy)(2)(H(2)PO(4))(PO(4))(2)].0.5H(2)O,a mixed-valence vanadium(IV,V) phosphate with a pillared layer structure

A mixed-valence vanadium phosphate, NH(4)[(V(2)O(3))(2)(4,4'-bpy)(2)(H(2)PO(4))(PO(4))(2)].0.5H(2)O, has been synthesized under hydrothermal conditions and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the monoclinic space group C2/c (No. 15) with a = 12.6354(8) A, b = 9.9786(6) A, c = 23.369(1) A, beta = 92.713(1) degrees, and Z = 4 with R(1) = 0.0389. The structure consists of dimers of edge-sharing vanadium(IV,V) octahedra that are connected by corner-sharing phosphate tetrahedra to form layers in the ab-plane, which are further linked through 4,4'-bipyridine pillars to generate a 3-D framework. Magnetic susceptibility confirms the valence of the vanadium atoms. The (31)P MAS NMR spectrum shows a resonance centered at 80 ppm with a shoulder at ca. 83 ppm in an intensity ratio close to 1:2, which correspond to two distinct P sites. The observed large downfield (31)P NMR shifts can be ascribed to magnetic exchange coupling involving phosphorus atoms. The unpaired electron spin density at the phosphorus nucleus was determined from variable-temperature (31)P NMR spectra. The (1)H MAS NMR spectrum was fitted to six components in accordance with the structure as determined from X-ray diffraction.     

Template-assisted solvothermal synthesis of five copper(I)-thioantimonate(III) composites: crystal structures and optical and thermal properties of (C6N2H18)0.5Cu2SbS3, (C4N3H15)0.5Cu2SbS3, (C8N4H22)0.5Cu2SbS3, (C4N3H14)Cu3Sb2S5, and (C6)N4H20)0.5Cu3Sb2S5

The novel copper(I)-thioantimonates(III) (C(6)N(2)H(18))(0.5)Cu(2)SbS(3) (I) (C(6)N(2)H(16) = 1,6-diaminohexane), (C(4)N(3)H(15))(0.5)Cu(2)SbS(3) (II) (C(4)N(3)H(13) = diethylenetriamine), (C(8)N(4)H(22))(0.5)Cu(2)SbS(3) (III) (C(8)N(4)H(20) = 1,4-bis(2-aminoethyl)piperazine), (C(4)N(3)H(14))Cu(3)Sb(2)S(5) (IV) (C(4)N(3)H(13) = diethylenetriamine), and (C(6)N(4)H(20))(0.5)Cu(3)Sb(2)S(5) (V) (C(6)N(4)H(18) = triethylenetetramine) were synthesized under solvothermal conditions reacting Sb, Cu, and S with the amines. The compounds I-III belong to the RCu(2)SbS(3) structure family (R = amine) and are built up of trigonal SbS(3) pyramids and two CuS(3) moieties forming 6-membered (6 MR) and 10-membered (10 MR) rings. The rings are condensed yielding single layers which are joined into [Cu(2)SbS(3)](-) double layers via Cu-S bonds. The organic ions are located between the anionic layers, and the shortest interlayer distances are 7.8 Angstroms (I), 7.4 Angstroms (II), and 8.8 Angstroms (III). The structure of the novel inorganic-organic hybrid compound IV contains one SbS(3) group, one SbS(4) unit, two CuS(3) triangles, and one CuS(4) tetrahedron. These units are joined into four-membered (4 MR) and six-membered rings (6 MR) forming a hitherto unknown strong undulated layered (Cu(3)Sb(2)S(5))(-) anion. Anions and cations are arranged in a sandwichlike manner with an interlayer distance of 6.184 A. The new composite V contains an anion with the same chemical composition as compound IV, but the structure exhibits a unique and different network topology which is constructed by two SbS(3) pyramids, two CuS(3) triangles, and one CuS(4) tetrahedron. These units are joined into 6 MR which may be described as an inorganic graphene-like layer or as a 6(3) net. Two such layers are connected via Cu-S bonds into the final double layer. The interlayer distance amounts to 6.44 Angstroms. All compounds decompose in a more or less complex manner when heated in an inert atmosphere.     

C6N2H14]0.5.[MnAl3(PO4)4(H2O)2]: a manganese(II)-substituted aluminophosphate with AFN topology

A new manganese(II)-substituted aluminophosphate, [C(6)N(2)H(14)]0.5.[MnAl(3)(PO(4))(4)(H(2)O)(2)], denoted as MnAPO-14, has been synthesized hydrothermally in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) as the structure-directing agent. Its structure is determined by single-crystal X-ray diffraction analysis and further characterized by X-ray powder diffraction, ICP, and TG analyses. The structure of MnAPO-14 is built up by MnO(4)(H(2)O)(2) octahedra, AlO(4) tetrahedra, and PO(4) tetrahedra via Al-O-P and Mn-O-P linkages. Its framework is analogous to that of aluminophosphate zeotype AFN in which 25% of the aluminum sites are replaced by Mn(II) atoms. The diprotonated DABCO cations reside in the eight-membered ring channels. Computational simulations indicate that the substitution site of Mn to Al is determined by the host-guest interaction. Crystal data: [C(6)N(2)H(14)]0.5.[MnAl(3)(PO(4))(4)(H(2)O)(2)], triclinic P1 (No. 2), a = 9.5121(4) A, b = 9.8819(3) A, c = 12.1172(4) A, alpha = 70.533(2) degrees, beta = 73.473(2) degrees, gamma = 82.328(2) degrees, Z = 2, R(1) = 0.0586 (I > 2 sigma(I)), and wR(2) = 0.1877 (all data).     

阴离子开放骨架磷酸盐[Al_4P_5O_(19)(OH)][C_6H_(18)N_2]和[Ga_8P_8O_(32)F_(5.5)][C_6H_(18)N_2]_2[H_3O~+]_(1.5)水热合成中的对映体拆分

以外消旋的2-甲基-1,5-戊二胺(MPMD)为结构导向剂,在水热条件下合成出新磷酸铝化合物[Al4P5O19(OH)][C6H18N2](AlPO-MPMD)和新磷酸镓化合物[Ga8P8O32F5.5][C6H18N2]2[H30+]1.5(GaPO-MPMD).采用单晶x射线衍射结构分析、粉末x射线衍射分析(XRD)、热重-差热分析(TGA-DTA.A)、固体核磁共振(MAs NMR)、旋光分析(Optical rotation)以及振动圆二色光谱分析(Vibrational circular dichroism,VCD)等技术对产物进行了表征.对产物的VCD实验光谱和理论模拟光谱对比分析及旋光分析表明,在水热合成过程中,具有S构象的手性结构导向剂分子比具有R构象的手性结构导向剂分子更多地进入无机化合物骨架中,显示了手性对映体分子在该水热条件下的原位手性拆分.     

H2bipy]2[(UO2)6Zn2(PO3OH)4(PO4)4].H2O: an open-framework uranyl zinc phosphate templated by diprotonated 4,4'-bipyridyl

Under mild hydrothermal conditions, a new organically templated uranyl zinc phosphate, [H 2bipy] 2[(UO 2) 6Zn 2(PO 3OH) 4(PO 4) 4].H 2O ( UZnP-2), has been synthesized. Structural analysis reveals that UZnP-2 is constructed from UO 7 pentagonal bipyramids that are linked into edge-sharing dimers that are in turn joined together by ZnO 4 and PO 4 tetrahedra to form a three-dimensional network. Intersecting channels occur along the a, b, and c axes. These channels house the diprotonated 4,4'-bipyridyl cations and water molecules. Ion-exchange experiments demonstrate that replacement of the 4,4'-bipyridyl cations by alkali and alkaline-earth metal cations results in a rearrangement of the framework. Further characterization of UZnP-2 is provided by Raman and fluorescence spectroscopy. The latter method reveals strong emission from the uranyl moieties with characteristic fine structure.     

Synthesis and characterization of fluorinated metal arsenates with a layer structure: (C4H12N2)(1.5)[M3F5(HAsO4)2(AsO4)] (M = Fe, Ga)

Two fluorinated metal arsenates, (C(4)H(12)N(2))(1.5)[M(3)F(5)(HAsO(4))(2)(AsO(4))] (M = Fe, Ga), have been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, magnetic susceptibility, M?ssbauer spectroscopy, and (71)Ga NMR spectroscopy. The two compounds are isostructural and crystallize in the monoclinic space group P2(1)/c (No. 14) with a = 8.394(1) A, b = 21.992(3) A, c = 10.847(1) A, beta = 96.188(2) degrees, and Z = 4 for the Fe compound, and a = 8.398(1) A, b = 21.730(3) A, c = 10.679(1) A, beta = 95.318(2) degrees, and Z = 4 for the Ga compound. The structure consists of infinite chains of corner-sharing MX(6) (X = O, F) octahedra and dimers of edge-sharing MO(3)F(3) octahedra, which are linked into two-dimensional sheets through arsenate tetrahedra with diprotonated piperazinium cations between the sheets. Magnetic susceptibility and M?ssbauer spectroscopy confirm the presence of Fe(III). The (71)Ga MAS NMR spectrum clearly shows a line shape consisting of three components, corresponding to three crystallographically distinct Ga sites.     

(C4N3H15)[(BO2)2(GeO2)4]: the first organically templated 3D borogermanate showing 1D 12-rings, large channels, and a novel zeolite-type framework topology constructed from Ge8O24 and B2O7 cluster units

The first organically templated 3D borogermanate with a novel zeolite-type topology, (C4N3H15)[(BO2)2(GeO2)4] FJ-17, has been solvothermally synthesized and characterized by IR spectroscopy, powder X-ray diffraction (PXRD), TGA, and single-crystal X-ray diffraction. The compound crystallized in the monoclinic space group P2(1)/c with a = 6.967(1) A, b = 10.500(1) A, c = 20.501(1) A, beta = 90.500(3) degrees , V = 1499.68(8) A3, and Z = 4. The framework topology of this compound is the previously unknown topology with the vertex symbols 3.4.3.9.3.8(2) (vertex 1), 3.8.3.4.6(2).9(2) (vertex 2), 3.8(2).4.6(2).6(2).8 (vertex 3), 4.8.4.8.8(3).12 (vertex 4), 4.8.4.8.8(2).12 (vertex 5), and 3.8.4.6(2).6.8(2) (vertex 6). The structure is constructed from Ge8O24 and B2O7 clusters. The Ge8O24 cluster contains eight GeO4 tetrahedra that share vertices; the B2O7 unit is composed of two BO4 tetrahedra sharing a vertex. The cyclic Ge8O24 clusters connect to each other through vertices to form a 2D layer with 8,12-nets. The adjacent layers are further linked by the dimeric B2O7 cluster units, resulting in a 3D framework with 12- and 8-ring channels along the a and b axes, respectively. In addition, there is a unique B2GeO9 3-ring in the structure.     

阴离子开放骨架磷酸盐[A14P5O19(OH)][C6H18N2]和[Ga8P8PO32F5.5][C6H18N2]2[H30+]1.5水热合成中的对映体拆分

以外消旋的2-甲基-1,5-戊二胺(MPMD)为结构导向剂,在水热条件下合成出新磷酸铝化合物[Al4P5O19(OH)][C6H18N2](AlPO-MPMD)和新磷酸镓化合物[Ga8P8O32F5.5][C6H18N2]2[H30+]1.5(GaPO-MPMD).采用单晶x射线衍射结构分析、粉末x射线衍射分析(XRD...     

(CH3)2NH(CH2)2NH(CH3)2][(UO2)2F2(HPO4)2]: a new organically templated layered uranium phosphate fluoride--synthesis, structure, characterization, and ion-exchange reactions

A new organically templated layered uranium phosphate fluoride, [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)][(UO(2))(2)F(2)(HPO(4))(2)] has been synthesized by hydrothermal reaction of UO(3), H(3)PO(4), HF, and (CH(3))(2)NCH(2)CH(2)N(CH(3))(2) at 140 degrees C. [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)][(UO(2))(2)F(2)(HPO(4))(2)] has a layered crystal structure consisting of seven-coordinated UO(5)F(2) pentagonal bipyramids and four-coordinated HPO(4) tetrahedra. Each anionic layer containing three-, four-, and six-membered rings is separated by [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)](2+) cations. The [(CH(3))(2)NH(CH(2))(2)NH(CH(3))(2)](2+) cations may be readily exchanged with the M(2+) ions (M = Ba, Sr and Ca) in water to give high crystalline AE(UO(2))(2)(PO(4))(2).6H(2)O (AE = Ca, Sr, Ba).     

Synthesis, crystal structure, and solid-state NMR spectroscopy of a new open-framework aluminophosphate (NH(4))(2)Al(4)(PO(4))(4)(HPO(4))xH(2)O

A new three-dimensional open-framework aluminophosphate (NH(4))(2)Al(4)(PO(4))(4)(HPO(4)).H(2)O (denoted AlPO-CJ19) with an Al/P ratio of 4/5 has been synthesized, using pyridine as the solvent and 2-aminopyridine as the structure-directing agent, under solvothermal conditions. The structure was determined by single-crystal X-ray diffraction and further characterized by solid-state NMR techniques. The alternation of the Al-centered polyhedra (including AlO(4), AlO(5), and AlO(6)) and the P-centered tetrahedra (including PO(4) and PO(3)OH) results in an interrupted open-framework structure with an eight-membered ring channel along the [100] direction. This is the first aluminophosphate containing three kinds of Al coordinations (AlO(4), AlO(5), and AlO(6)) with all oxygen vertexes connected to framework P atoms. (27)Al MAS NMR, (31)P MAS NMR, and (1)H --> (31)P CPMAS NMR characterizations show that the solid-state NMR techniques are an effective complement to XRD analysis for structure elucidation. Furthermore, all of the possible coordinations of Al and P in the aluminophosphates with an Al/P ratio of 4/5 are summarized. Crystal data: (NH(4))(2)Al(4)(PO(4))(4)(HPO(4))xH(2)O, monoclinic P2(1) (No. 4), a = 5.0568(3) A, b = 21.6211(18) A, c = 8.1724(4) A, beta = 91.361(4) degrees , V = 893.27(10) A(3), Z = 2, R(1) = 0.0456 (I > 2 sigma(I)), and wR(2) = 0.1051 (all data).     

Syntheses, structures, ionic conductivities, and magnetic properties of three new transition-metal borophosphates Na5(H3O){M(II)3[B3O3(OH)]3(PO4)6}.2H2O (M(II) = Mn, Co, Ni)

Three new open-framework transition-metal borophosphates Na5(H3O){M(II)3[B3O3(OH)]3(PO4)6}.2H2O (M(II) = Mn, Co, Ni) (denoted as MBPO-CJ25) have been synthesized under mild hydrothermal conditions. Single-crystal X-ray diffraction analyses reveal that the three compounds possess isostructural three-dimensional (3D) open frameworks with one-dimensional 12-ring channels along the [001] direction. Notably, the structure can also be viewed as composed of metal phosphate layers [M(II)(PO4)2]4- with Kagomé topology, which are further connected by [B3O7(OH)] triborates, giving rise to a 3D open framework. The guest water molecules locate in the 12-ring channels. Partial Na+ ions reside in the 10-ring side pockets within the wall of the 12-ring channels, and the other Na+ ions and protonated water molecules locate in the 6-ring windows delimited by MO6 and PO4 polyhedra to compensate for the negative charges of the anionic framework. These compounds show a high thermal stability and are stable upon calcinations at ca. 500 degrees C. Ionic conductivities, due to the motion of Na+ ions, are measured for these three compounds. They have similar activation energies of 1.13-1.25 eV and conductivities of 2.7 x 10(-7)-9.9 x 10(-7) S cm(-1) at 300 degrees C. Magnetic measurements reveal that there are very weak antiferromagnetic interactions among the metal centers of the three compounds. Crystal data: MnBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.9683(5) A, c = 12.1303(6) A, and Z = 2; CoBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.7691(15) A, c = 12.112(2) A, and Z = 2; NiBPO-CJ25, hexagonal, P6(3)/m (No. 176), a = 11.7171(5) A, c = 12.0759(7) A, and Z = 2.     

MIL-50, an open-framework GaPO with a periodic pattern of small water ponds and dry rubidium atoms: a combined XRD,NMR, and computational study

A new fluorinated gallium phosphate, MIL-50, has been synthesized under mild hydrothermal conditions using 1,6-diaminohexane. The chemical formula of MIL-50 is Rb(2)Ga(9)(PO(4))(8)(HPO(4))(OH)F(6).2N(2)C(6)H(18).7H(2)O. The structure is a network of hexameric units of Ga(3)(PO(4))(3)F(2) and Ga(3)(PO(4))(2)(HPO(4))F(3) via corner sharing. It creates a three-dimensional open-framework delimiting 6- and 18-ring channels running along the c axis. The diprotonated 1,6-diaminohexane and water molecules are trapped within the 18-ring pores, whereas the rubidium cations reside in the 6-ring ones. A double quantum (31)P NMR experiment and partial charge calculations indicate that water molecules are present under the form of periodic small clusters, lowering the multiplicity of one phosphorus site, P3. Though water hops within the clusters, the motion leaves the water pattern periodic. Rubidium is so tightly embedded into the framework that water moving in the large 18-ring channels does not reach it, leaving it therefore dry. The crystal framework may be ascribed to the orthorhombic space group Cmc2(1) (n degrees 36), a = 32.1510(2), b = 17.2290(3), c = 10.2120(1) A. The periodic water pattern has a different symmetry than that of the framework. A method has been devised to superpose the two sublattices that coexist in the same unit cell in order to have full occupancy of each site and to perform Madelung summations. This original method is of general interest for most zeolitic materials exhibiting a different symmetry for the framework and the template sublattices.     

High-temperature, high-pressure hydrothermal synthesis, crystal structure, and solid-state NMR spectroscopy of Cs2(UO2)(Si2O6) and variable-temperature powder X-ray diffraction study of the hydrate phase Cs2(UO2)(Si2O6) x 0.5H2O

A new uranium(VI) silicate, Cs2(UO2)(Si2O6), has been synthesized by a high-temperature, high-pressure hydrothermal method and characterized by single-crystal X-ray diffraction and solid-state NMR spectroscopy. It crystallizes in the orthorhombic space group Ibca (No. 73) with a = 15.137(1) A, b = 15.295(1) A, c = 16.401(1) A, and Z = 16. Its structure consists of corrugated achter single chains of silicate tetrahedra extending along the c axis linked together via corner-sharing by UO6 tetragonal bipyramids to form a 3-D framework which delimits 8- and 6-ring channels. The Cs+ cations are located in the channels or at sites between channels. The 29Si and 133Cs MAS NMR spectra are consistent with the crystal structure as determined from X-ray diffraction, and the resonances in the spectra are assigned. Variable-temperature in situ powder X-ray diffraction study of the hydrate Cs2(UO2)(Si2O6) x 0.5H2O indicates that the framework structure is stable up to 800 degrees C and transforms to the structure of the title compound at 900 degrees C. A comparison of related uranyl silicate structures is made.     

C5H14N2][(MoO3)3(SO4)].H2O: sulfated alpha-molybdena chains

Recent work in the preparation of organically templated metal sulfates under hydrothermal conditions has been extended to include the sulfation of alpha-molybdena through the synthesis of [C(5)H(14)N(2)][(MoO(3))(3)(SO(4))].H(2)O. Single crystals were grown under hydrothermal conditions from molybdenum oxide, water, sulfuric acid, and an enantiomerically pure (R)-2-methylpiperazine source and characterized using both single-crystal X-ray diffraction and infrared spectroscopy. One-dimensional [(MoO(3))(3)(SO(4))](n)(2n-) chains, based on a neutral alpha-molybdena backbone, are connected through an extensive hydrogen-bonding network containing [C(5)H(14)N(2)](2+) cations and occluded water molecules. The direction of the hydrogen bonding is primarily dictated by the nucleophilicity of the respective oxide ligands, as determined using bond valence sums.     

Amino acid templating of inorganic networks: synthesis and structure of L-asparagine zinc phosphite, C4N2O3H8.ZnHPO3

C(4)N(2)O(3)H(8).ZnHPO(3) is the first zincophosphite framework to be templated by an amino acid (l-asparagine), which bonds to Zn via a carboxyl O atom. It contains infinite, homochiral, helical 4-ring chains of ZnO(4) and HPO(3) groups, stabilized by intra- and interchain N-H.O hydrogen bonds. Crystal data: C(4)N(2)O(3)H(8).ZnHPO(3), M(r) = 277.49, orthorhombic, P2(1)2(1)2(1) (No. 19), a = 5.0349(2) A, b = 9.4539(4) A, c = 18.6092(8) A, V = 885.79 (6) A(3), Z = 4.     

Solid-state (14)N MAS NMR of ammonium ions as a spy to structural insights for ammonium salts

The high resolution offered by magic-angle spinning (MAS), when compared to the static condition in solid-state NMR of powders, has been used to full advantage in a (14)N MAS NMR study of some ammonium salts: CH(3)NH(3)Cl, (NH(4))(2)(COO)(2) x H(2)O, (CH(3))(3)(C(6)H(5)CH(2))NCl, (CH(3))(3)(C(6)H(5))NI, [(n-C(4)H(9))(4)N](2)Mo(2)O(7), (NH(4))(2)HPO(4), and NH(4)H(2)PO(4). It is shown that the high-quality (14)N MAS NMR spectra, which can be obtained for these salts, allow determination of the (14)N quadrupole coupling parameters, i.e. C(Q) (the quadrupole coupling constant) and eta(Q) (the asymmetry parameter), with very high precision. In particular, it is shown that precise C(Q), eta(Q) parameters can be determined for at least two different (14)N sites in case the individual spinning-sideband (ssb) intensities arise from a single manifold of ssbs, i.e. the ssbs for the two sites cannot be resolved. This feature of (14)N MAS NMR, which is the first demonstration for manifolds of ssb in MAS NMR without the potential information from a central transition, becomes especially useful at the slow spinning frequencies (nu(r) = 1000-1500 Hz) applied to some of the ammonium salts studied here. The detection of the number of sites has been confirmed by the corresponding crystal structures determined from single-crystal X-ray diffraction (XRD), either in this work for the unknown structure of benzyl trimethylammonium chloride or from reports in the literature. The magnitudes of the (14)N quadrupole coupling constants for the ammonium salts studied here are in the range from C(Q) approximately 20 kHz to 1 MHz while the asymmetry parameters span the full range 0 < or = eta(Q) < or = 1. Clearly, the (14)N quadrupole coupling parameters (C(Q), eta(Q)) for ammonium ions appear highly sensitive toward crystal structure and therefore appreciably more informative for the characterization of ammonium salts in comparison to the isotropic (14)N (or (15)N) chemical shifts.     

An organically templated cobalt-vanadium oxide with beta cage units: hydrothermal synthesis and x-ray structural characterization of (C(2)H(10)N(2))[Co(2)(C(2)O(4))V(4)O(12)

A novel organically templated cobalt-vanadium oxalate, (C(2)H(10)N(2))[Co(2)(C(2)O(4))V(4)O(12)], was synthesized under mild hydrothermal conditions and characterized by single-crystal/powder X-ray diffraction, infrared spectroscopy, and thermogravimetric analysis. The compound crystallizes in an orthorhombic system with space group Cmcm and cell parameters a = 11.527(2) A, b = 9.9476(18) A, c = 14.780(3) A. The compound possesses 3-dimensional topologies with sodalite analogue structure and is constructed by C(2)O(4)-incorporated beta cage units. On the basis of the results of TG/DTA analyses, the structure is thermally stable up to approximately 573 K.