In situ X-ray diffraction study of cesium exchange in synthetic umbite

The exchange of Cs(+) into H(1.22)K(0.84)ZrSi(3)O(9)·2.16H(2)O (umbite-(HK)) was followed in situ using time-resolved X-ray diffraction at the National Synchrotron Light Source. The umbite framework (space group P2(1)/c with cell dimensions of a = 7.2814(3) ?, b = 10.4201(4) ?, c = 13.4529(7) ?, and β = 90.53(1)°) consists of wollastonite-like silicate chains linked by isolated zirconia octahedra. Within umbite-(HK) there are two unique ion exchange sites in the tunnels running parallel to the a-axis. Exchange Site 1 is marked by 8 member-ring (MR) windows in the bc-plane and contains K(+) cations. Exchange Site 2 is marked by a larger 8-MR channel parallel to [100], and contains H(2)O molecules. The occupancy of the Cs(+) cations through these channels was modeled by Rietveld structure refinements of the diffraction data and demonstrated that there is a two-step exchange process. The incoming Cs(+) ions populated the larger 8-MR channel (Exchange Site 2) first and then migrated into the smaller 8-MR channel. During the exchange process a structural change occurs, transforming the exchanger from monoclinic P2(1)/c to orthorhombic P2(1)2(1)2(1). This structural change occurs when Cs(+) occupancy in the small cavity becomes greater than 0.50. The final in situ ion exchange diffraction pattern was refined to yield umbite-(CsK) with the molecular formula H(0.18)K(0.45)Cs(1.37)ZrSi(3)O(9)·0.98H(2)O and possessing an orthorhombic unit cell with dimensions a = 10.6668(8) ?, b = 13.5821(11) ?, c = 7.3946(6) ?. Solid state (133)Cs MAS NMR showed there is only a slight difference between the two cavities electronically. Valence bond sums for the completely occupied Exchange Site 1 demonstrate that Cs-O bonds of up to 3.8 ? contribute to the coordination of the Cs(+) cation.     

Structural Changes and Phase Transitions in Whitlockite-Like Phosphates

New compounds with a g -Ca 3 (PO 4 ) 2 structure type were found in three systems: Sr 9+ x M 1.5 m x (PO 4 ) 7 ( M = Mn, Fe, Co, Ni, Cu, and Cd; space group R 3 m ; Z = 3), Sr 9 R (PO 4 ) 7 ( R = Al, Sc, Cr, Fe, Ga, In, and Gd-Lu; space group P 2/ c , Z = 4), and Sr 9+2 x M 1+ x A 1 m 6 x (PO 4 ) 7 ( M = Mn, Ni, Cd; space group R 3 c and Z = 6 for A = Na, K; space group P 2/ m and Z = 4 for A = Li). Crystal structures of these compounds were determined by time-of-flight neutron, synchrotron X-ray, and laboratory X-ray powder diffraction. Reversible polar-to-centrosymmetric phase transitions ( R 3 c {\begin{array}{c}\\[-14pt]\hspace*{.5pt}\to\\[-7pt]\hspace*{-.5pt}\gets \end{array}} R 3 m ) were observed at high temperatures in Ca 3 m x Sr x (PO 4 ) 2 (0 h x h 12/7), Ca 10.5 m 1.5 x Fe x (PO 4 ) 7 (0 h x h 1), and Ca 9 R (PO 4 ) 7 . Solid solutions Ca 3 m x Sr x (PO 4 ) 2 (13/7 h x h 16/7) are centosymmetric with space group R 3 m at room temperature. These phase transitions were studied by high-temperature X-ray diffraction, second-harmonic generation, DSC, electric-conductivity and dielectric measurements.     

Rationally designed, polymeric, extended metal-ciprofloxacin complexes

Reactions of the antimicrobial fluoroquinolone ciprofloxacin (cfH) with metal salts in the presence of aromatic polycarboxylate ligands or under basic conditions produce fourteen new metal-cfH complexes, namely, [Ba2(cf)2(1,4-bdc)(H2O)2] x H2O (1), [Sr6(cf)6(1,4-bdc)3(H2O)6] x 2H2O (2), [M2(cfH)2(bptc)(H2O)2] x 8H2O (M = Mn3 and Cd4), [M(cfH)(1,3-bdc)] (M = Mn5, Co6, and Zn7), [Zn2(cfH)4(1,4-bdc)](1,4-bdc) x 13H2O (8), [Ca(cfH)2(1,2-Hbdc)2] x 2H2O (9) and [M(cf)2] x 2.5H2O (M = Mn10, Co11, Zn12, Cd13, and Mg14) (1,4-bdc = 1,4-benzenedicarboxylate, bptc = 3,3',4,4'-benzophenonetetracarboxylate, 1,3-bdc = 1,3-benzenedicarboxylate, 1,2-bdc = 1,2-benzenedicarboxylate). Their structures were determined by single-crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. The structures of 1 and 2 consist of unique two-dimensional arm-shaped layers. Compounds 3 and 4 are isostructural and feature one-dimensional structures formed from the interconnection of [M2(cfH)2(H2O)2] dimers with bptc ligands. Compounds 5-7 are isostructural and contain double-chain-like ribbons constructed from [M2(cfH)2(CO2)2] dimers and 1,3-bdc. Compound 8 consists of a pair of [Zn(cfH)2]2+ fragments bridged by a 1,4-bdc into a dinuclear dumbbell structure. Compound 9 is a neutral monomeric complex. To the best of our knowledge, compounds 1-9 are the first examples of metal-quinolone complexes that contain aromatic polycarboxylate ligands. Compounds 10-14 are isostructural and exhibit interesting two-dimensional rhombic grids featuring large cavities with dimensions of 13.6x13.6 A. Up to now, polymeric extended metal-cfH complexes have never been reported.     

Syntheses and Crystal Structures of two Ring—like {Mo18}Cluster Compounds

1INTRODUCTIONThepolyoxomolybdateshavebeenwidelyresearchedinmanyfieldssuchascatalysis,biology,medicineandmaterialsciencebecauseoftheirrichphysicalandchemicalproperties[1].Thoughmanypolyoxomolybdateshavebeenreported[2],furtherresearchisstillnecessaryforthestudyof搑eduction-oxidation-reconstitution?self-assemblyprocesses[3,4].Polyoxomolybdatesarenormallybuiltupundersuitableconditionsbyafewbuildingblockssuchas{Mo2},{Mo8}and{Mo9}inself-assemblyway[5,6].The{Mo18}clustershaveseveralstructuralty…     

Sr2GaScO5, Sr10Ga6Sc4O25, and SrGa0.75Sc0.25O2.5: a play in the octahedra to tetrahedra ratio in oxygen-deficient perovskites

Three different perovskite-related phases were isolated in the SrGa(1-x)Sc(x)O(2.5) system: Sr(2)GaScO(5), Sr(10)Ga(6)Sc(4)O(25), and SrGa(0.75)Sc(0.25)O(2.5). Sr(2)GaScO(5) (x = 0.5) crystallizes in a brownmillerite-type structure [space group (S.G.) Icmm, a = 5.91048(5) ?, b = 15.1594(1) ?, and c = 5.70926(4) ?] with complete ordering of Sc(3+) and Ga(3+) over octahedral and tetrahedral positions, respectively. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) (x = 0.4) was determined by the Monte Carlo method and refined using a combination of X-ray, neutron, and electron diffraction data [S.G. I4(1)/a, a = 17.517(1) ?, c = 32.830(3) ?]. It represents a novel type of ordering of the B cations and oxygen vacancies in perovskites. The crystal structure of Sr(10)Ga(6)Sc(4)O(25) can be described as a stacking of eight perovskite layers along the c axis ...[-(Sc/Ga)O(1.6)-SrO(0.8)-(Sc/Ga)O(1.8)-SrO(0.8)-](2).... Similar to Sr(2)GaScO(5), this structure features a complete ordering of the Sc(3+) and Ga(3+) cations over octahedral and tetrahedral positions, respectively, within each layer. A specific feature of the crystal structure of Sr(10)Ga(6)Sc(4)O(25) is that one-third of the tetrahedra have one vertex not connected with other Sc/Ga cations. Further partial replacement of Sc(3+) by Ga(3+) leads to the formation of the cubic perovskite phase SrGa(0.75)Sc(0.25)O(2.5) (x = 0.25) with a = 3.9817(4) ?. This compound incorporates water molecules in the structure forming SrGa(0.75)Sc(0.25)O(2.5)·xH(2)O hydrate, which exhibits a proton conductivity of ～2.0 × 10(-6) S/cm at 673 K.     

Self-assembly of a series of extended architectures based on polyoxometalate clusters and silver coordination complexes

Three unusual compounds based on polyoxometalate building blocks, [(H2O)5Na2(C6NO2H4)(C6NO2H5)3Ag2][Ag2IMo6O24(H2O)4] x 6.25H2O (1), [(H2O)4Na2(C6NO2H5)6Ag3][IMo6O24] x 6H2O (2), and (C6NO2H6)2[(C6NO2H5)2Ag][Cr(OH)6Mo6O18] x 4H2O (3), have been synthesized and characterized by elemental analysis; IR, XPS, and ESR spectroscopy; TG analysis; and single-crystal X-ray diffraction. Compound 1 is constructed from the cationic two-dimensional (2D) coordination polymer sheets which are constituted of [(H2O)5Na2(C6NO2H4)(C6NO2H5)3Ag2]3+ and anionic [Ag2IMo6O24(H2O)4]3- chains as pillars, forming a three-dimensional (3D) supramolecular framework via weak Ag-O interactions. Compound 2 is composed of the well-defined [IMo6O24]5- building blocks, which are linked through trinuclear Ag-pyridine-3-carboxylic acid, [(C6NO2H5)6Ag3]3+, fragments into a one-dimensional (1D) hybrid chain; adjacent chains are further connected by sodium cations to yield a novel 2D network. Compound 3 has a 1D chainlike structure constructed from [Cr(OH)6Mo6O18]3- building blocks and Ag-pyridine-4-carboxylic acid coordination units. The crystal data for these compounds are the following: 1, triclinic, P1, a = 13.280(3) A, b = 13.641(3) A, c = 16.356(3) A, alpha = 89.68(3) degrees, beta = 88.31(3) degrees, gamma = 75.87(3) degrees, Z = 2; 2, triclinic, P1, a = 11.978(2) A, b = 12.008(2) A, c = 13.607(3) A, alpha = 116.14(3) degrees, beta = 108.85(3) degrees, gamma = 93.86(3) degrees, Z = 1; 3, triclinic, P1, a = 10.458(2) A, b = 10.644(2) A, c = 12.295(3) A, alpha = 97.40(3) degrees, beta = 112.38(3) degrees, gamma = 113.59(3) degrees, Z = 1.     

Ozone reactions with alkaline-earth metal cations and dications in the gas phase: room-temperature kinetics and catalysis

Room-temperature rate coefficients and product distributions are reported for the reactions of ozone with the cations and dications of the alkaline-earth metals Ca, Sr, and Ba. The measurements were performed with a selected-ion flow tube (SIFT) tandem mass spectrometer in conjunction with either an electrospray (ESI) or an inductively coupled plasma (ICP) ionization source. All the singly charged species react with ozone by O-atom transfer and form monoxide cations rapidly, k = 4.8, 6.7, and 8.7 x 10(-10) cm3 molecule(-1) s(-1) for the reactions of Ca+, Sr+, and Ba+, respectively. Further sequential O-atom transfer occurs to form dioxide and trioxide cations. The efficiencies for all O-atom transfer reactions are greater than 10%. The data also signify the catalytic conversion of ozone to oxygen with the alkaline-earth metal and metal oxide cations serving as catalysts. Ca2+ reacts rapidly with O3 by charge separation to form CaO+ and O2+ with a rate coefficient of k = 1.5 x 10(-9) cm3 molecule(-1) s(-1). In contrast, the reactions of Sr2+ and Ba2+ are found to be slow and add O3, (k >/= 1.1 x 10-11 cm3 molecule-1 s-1). The initial additions are followed by the rapid sequential addition of up to five O3 molecules with values of k between 1 and 5 x 10(-10) cm3 molecule(-1) s(-1). Metal/ozone cluster ions as large as Sr2+(O3)5 and Ba2+(O3)4 were observed for the first time.     

Influence of hydrogen bonding on the assembly of six-membered vanadium borophosphate cluster anions: synthesis and structures of (NH4)2(C2H10N2)6[Sr(H2O)5]2[V2P2BO12](6)10H2O, (NH4)2(C3H12N2)6[Sr(H2O)4]2[V2P2BO12](6)17H2O, and (NH4)3(C4H14N2)4 5[Sr(H2O)5]2[Sr(H2O)4][V2P2BO12]6 10H2O

Three new strontium vanadium borophosphate compounds, (NH4)2(C2H10N2)6[Sr(H2O)5]2[V2P2BO12]6 10H2O (Sr-VBPO1) (1), (NH4)2(C3H12N2)6[Sr(H2O)4]2[V2P2BO12]6 17H2O (Sr-VBPO2) (2), and (NH4)3(C4H14N2)4.5[Sr(H2O)5]2[Sr(H2O)4][V2P2BO12]6 10H2O (Sr-VBPO3) (3) have been synthesized by interdiffusion methods in the presence of diprotonated ethylenediamine, 1,3-diaminopropane, and 1,4-diaminobutane. Compound 1 has a chain structure, whereas 2 and 3 have layered structures with different arrangements of [(NH4) [symbol: see text] [V2P2BO12]6] cluster anions within the layers. Crystal data: (NH4)2(C2H10N2)6[Sr(H2O)5]2[V2P2BO12]6 10H2O, monoclinic, space group C2/c (no. 15), a = 21.552(1) A, b = 27.694(2) A, c = 20.552(1) A, beta = 113.650(1) degrees, Z = 4; (NH4)2(C3H12N2)6[Sr(H2O)4]2[V2P2BO12]6 17H2O, monoclinic, space group I2/m (no. 12), a = 15.7618(9) A, b = 16.4821(9) A, c = 21.112(1) A, beta = 107.473(1) degrees, Z = 2; (NH4)3(C4H14N2)4.5[Sr(H2O)5]2[Sr(H2O)4] [V2P2BO12]6 10H2O, monoclinic, space group C2/c (no. 15), a = 39.364(2) A, b = 14.0924(7) A, c = 25.342(1) A, beta = 121.259(1) degrees, Z = 4. The differences in the three structures arise from the different steric requirements of the amines that lead to different amine-cluster hydrogen bonds.     

Influence of pH and organic ligands on the supramolecular network based on molybdenum phosphate/strontium chemistry

Three supramolecular materials based on different poly(oxomolybdophosphate) clusters, (H(2)imi)(6)(Himi)(4)[{Sr(H(2)O)(4)}(2){Sr ? P(6)Mo(4)(V)Mo(14)(VI)O(73)}(2)]·17H(2)O (1), (H(2)(4,4'-bpy))(2)[Cu(2)Sr(2)Mo(12)O(24)·(OH)(6)(H(2)O)(6)(H(2)PO(4))(2)(HPO(4))(2)(PO(4))(4)]·5H(2)O (2), and (H(2)bim)(H(2)bim)[SrP(2)Mo(5)O(23)(H(2)O)(3)]·2H(2)O (3) (imi = imidazole, 4,4'-bpy = 4,4'-bipyridine, and bim = 2,2'-biimidazole), have been hydrothermally synthesized and structurally characterized by the elemental analysis, TG, IR, UV-vis, XPS and the single-crystal X-ray diffraction. Compound 1 is made up of unusual basket-shape [Sr ? P(6)Mo(18)O(73)](10-) cages linked by [Sr(H(2)O)(4)](2+) fragments to yield unprecedented dimeric chains, which represent the first 1-D assemblies of basket-type POMs. Compound 2 exhibits a novel string constructed from sandwich-like [Cu(P(4)Mo(6)O(31))(2)] units and {Sr(2)Cu} trinuclear linkers. Compound 3 is the first chain of Strandberg-type polyoxoanions connected by Sr(2+) cations. All the 1-D chains are further packed into various 3-D supramolecular assemblies via strong hydrogen-bonding interactions. The electrochemical and electrocatalysis behavior of 1, 2, and 3-CPE have been investigated in detail.     

Effect of explicit cationic size and valence constraints on the phase stability of 1:2 B-site-ordered perovskite ruthenates

The related parameters of cation size and valence that control the crystallization of Sr(3)CaRu(2)O(9) into a 1:2 B-site-ordered perovskite structure were explored by cationic substitution at the strontium and calcium sites and by the application of high pressure. At ambient pressures, Sr(3)MRu(2)O(9) stoichiometries yield multiphasic mixtures for M = Ni(2+), Mg(2+), and Y(3+), whereas pseudocubic perovskites result for M = Cu(2+) and Zn(2+). For A-site substitutions, an ordered perovskite structure results for Sr(3-x)Ca(x)CaRu(2)O(9), with 0 相似文献   

类钙钛矿结构新钽酸盐KSr2Ta3O10的合成、结构与层间特性

类钙钛矿结构氧化物是由钙钛矿结构基元与其它类型结构基元组合而成的一种超结构复合氧化物.     

Expanding the crystal chemistry of uranyl peroxides: synthesis and structures of di- and triperoxodioxouranium(VI) complexes

Four compounds containing tri- and diperoxodioxouranium(VI) complexes have been synthesized under ambient conditions and structurally characterized. The crystal structures of Na4(UO2)(O2)3(H2O)12 (monoclinic, P21/c, a=6.7883(6) A, b=16.001(2) A, c=16.562(2) A, beta=91.917(2) degrees, V=1797.9(3) A3, Z=4) and Ca2(UO2)(O2)3(H2O)9 (orthorhombic, Pbcn, a=9.576(3) A, b=12.172(3) A, c=12.314(2) A, V=1435.4(6) A3, Z=4) contain clusters of triperoxodioxouranium(VI). These clusters are bonded through a network of H bonding to H2O groups and in the Ca compound by bonds to Ca2+ cations. In the crystal structure of Na2Rb4(UO2)2(O2)5(H2O)14 (orthorhombic, Pbcm, a=6.808(2) A, b=16.888(6) A, c=23.286(8) A, V=2677.5(16) A3, Z=4), triperoxodioxouranium(VI) polyhedra share a peroxide edge, forming dimers of polyhedra of composition (UO2)2(O2)5(6-). Adjacent dimers are linked through bonding to Rb+ cations and by H bonds to H2O groups. The crystal structure of K6[(UO2)(O2)2(OH)]2(H2O)7 (orthorhombic, Pcca, a=15.078(8) A, b=6.669(4) A, c=23.526(13) A, V=2366(2) A3, Z=4) contains diperoxodioxouranium(VI) polyhedra that include two OH groups. These polyhedra share an OH-OH edge, forming dimers of composition (UO2)2(O2)4(OH)2(6-). The dimers are linked by bonds to K+ cations and by H bonding to H2O groups.     

Synthesis and characterization of zirconogermanates

Six new zirconogermanates have been prepared under hydrothermal conditions using amines as bases. There are four new structure types (ASU-n) with a common motif of ZrGe(5). ASU-23 is a layered structure: ZrGe(3)O(8)(OH)F.[C(10)H(26)N(4)].H(2)O, space group P2(1)/n, a = 6.7957(8) A, b = 12.700(1) A, c = 24.293(3) A, beta = 97.936(2) degrees, V = 2076.4(4) A(3). ASU-24 is a pillared layered structure: Zr(3)Ge(6)O(18)(OH(2),F)(4)F(2).[C(6)H(18)N(2)].[C(6)H(17)N(2)](2).2H(2)O, space group P2(1)/n, a = 7.4249(3) A, b = 25.198(1) A, c = 11.3483(5) A, beta = 90.995(1) degrees, V = 2122.9(2) A(3). This material has the lowest framework density (FD) of any oxide material that we are aware of (FD = 8.48 metal atoms/nm(3)). Two other materials form three-dimensional open-frameworks, ASU-25: ZrGe(3)O(9).[C(3)H(12)N(2)], space group P112(1)/a, a = 13.1994(4) A, b = 7.6828(2) A, c = 11.2373(3) A, gamma = 91.233(3) degrees, V = 1139.29(5) A(3). The other is ASU-26: ZrGe(3)O(9).[C(2)H(10)N(2)], space group Pn, a = 13.7611(3) A, b = 7.7294(2) A, c = 11.2331(3) A, beta = 104.793(1) degrees, V = 1155.21(4) A(3). ASU-25 is related to the mineral umbite K(2)ZrSi(3)O(9).H(2)O. The germanium equivalent has been prepared through the inorganic route: K(2)ZrGe(3)O(9).H(2)O, space group P2(1)2(1)2(1), a = 13.6432(6) A, b = 7.4256(3) A, c = 10.3973(4) A, V = 1053.33(8) A(3). The structural relationships between ASU-25 and its inorganic counterpart are described. The thermal decomposition of the germanium umbite generated the cyclic trigermanate K(2)ZrGe(3)O(9), analogue of the mineral wadeite, crystallizing in the orthorhombic system, a = 7.076 A, b = 12.123 A, c = 10.451 A, V = 904.5 A(3).     

A New Bis-(As_3O_6) Capping 6-Molybdonickelate Complex:Preparation and Characterization of [Ni(en)_2(H_2O)]_2[(NiO_6)Mo_6O_(18)(As_3O_3)_2]·2H_2O

A new complex constructed from a unit with two As3O6 rings capping Anderson-type moieties,[Ni(en)2(H2O)2]2[(NiO6)Mo6O18(As3O3)2]·2H2O(1,en = ethylenediamine),has been hydrothermally synthesized and characterized by IR,single-crystal X-ray diffraction and thermogra-vimetric analysis.The compound crystallizes in triclinic,space group P1 with a = 9.1230(16),b = 11.8078(9),c = 12.2111(9) ,α = 114.5210(10),β = 98.0350(10),γ = 100.0320(10)o,Mr = 2029.80,C8H44As6Mo6N8Ni3O36,V = 1145.0(2) 3,Dc = 2.944 g/cm3,Z = 1,GOF = 0.997,μ = 7.203 mm-1,F(000) = 970,R = 0.0352 and wR = 0.1019.Compound 1 consists of an Anderson-type capped by a two-ring(As3O6) unit [(NiO6)Mo6O18(As3O3)2]4-,two six-coordinate [Ni(en)2(H2O)2]2+ cations and two water molecules.     

An unusual 3D coordination polymer based on bridging interactions of the nucleobase adenine

The first 3D coordination polymer containing a nucleobase as a bridging ligand, [[Cu2(mu-ade)4(H2O)2][Cu(ox)(H2O)]2 x approximately 14H2O]n (1), has been synthesized by reaction of adenine (Hade) with a basic solution of K2[Cu(ox)2] x 2H2O (ox = oxalato dianion). Compound 1 crystallizes in the trigonal space group R3 with a = b = 31.350(1) angstroms, c = 14.285(1) angstroms, V = 12158.7(10) angstroms3, and Z = 9. X-ray analysis shows a covalent 3D network in which the copper(II) centers are bridged by tridentate mu-N3,N7,N9 adeninate ligands. The compound has relatively large, nanometer-sized tubes associated with the self-assembly process directed solely by metal-ligand interactions. The covalent 3D framework remains intact upon removal of the guest water molecules trapped in the nanotubes. Magnetic measurements indicate an overall antiferromagnetic behavior of the compound.     

Vibrational analysis of Ag3(PO2NH)3, Na3(PO2NH)3 x H2O, Na3(PO2NH)3 x 4H2O,

FT IR and FT Raman spectra of Ag3(PO2NH), (Compound 1), Na3(PO2NH)3 x H2O (Compound II), Na3(PO2NH)3 x 4H2O (Compound III), [C(NH2)3]3(PO2NH)3 x H2O (Compound IV) and (NH4)4(PO2NH)4 x 4H2O (Compound V) are recorded and analyzed on the basis of the anions, cations and water molecules present in each of them. The PO2NH- anion ring in compound I is distorted due to the influence of Ag+ cation. Wide variation in the hydrogen bond lengths in compound III is indicated by the splitting of the v2 and v3 modes of vibration of water molecules. The NH4 ion in compound V occupies lower site symmetry and exhibits hindered rotation in the lattice. The correlations between the symmetric and asymmetric stretching vibrations of P-N-P bridge and the P-N-P bond angle have also been discussed.     

Synthesis, crystal structure, and porosity estimation of hydrated erbium terephthalate coordination polymers

The reaction of the Er3+ ion with polycarboxylate ligands in gel media leads to coordination polymers exhibiting various structural types and dimensionalities. Five Er3+/1,4-benzenedicarboxylate-based coordination polymers have been obtained in such conditions. Four out of the five are new. Their crystal structures are reported and compared herein. Compound 1, namely, Er2Ter3(H2O)6, where H2Ter symbolizes the terephthalic acid, crystallizes in the space group P1 (No. 2) with a = 7.8373(10) A, b = 9.5854(2) A, c = 10.6931(2) A, alpha = 68.7770(8) degrees, beta = 70.8710(8) degrees, and gamma = 75.3330(12) degrees. It has already been reported elsewhere. The last four compounds are new. Compound 2, namely, Er2Ter3(H2O)6 x 2 H2O, crystallizes in the space group P121/a1 (No. 14) with a = 6.7429(2) A, b = 22.4913(7) A, c = 9.6575(3) A, and beta = 91.6400(18) degrees. Compound 3, namely Er2Ter3(H2O)8 x 2 H2O crystallizes in the space group P1 (No. 2) with a = 7.5391(2) A, b = 10.0533(3) A, c = 10.4578(3) A, alpha = 87.7870(10) degrees, beta = 82.5510(11) degrees, and gamma = 86.2800(16) degrees. Compound 4, namely, Er2Ter3(H2O)6 x 2 H2O crystallizes in the space group C2/c (No. 15) with a = 38.5123(13) A, b = 11.1241(4) A, c = 7.0122(2) A, and beta = 98.634(2) degrees. Compound 5, namely, Er2Ter3(H2O)6 x H2O, crystallizes in the space group P1 (No. 2) with a = 6.8776(10) A, b = 11.0420(2) A, c = 18.5675(3) A, alpha = 84.7240(6) degrees, beta = 81.8380(6) degrees, and gamma = 84.1770(8) degrees. A computational method has also been developed to evaluate the potential porosity of the coordination polymers. This method is described and then applied to the different Er2Ter3(H2O)n coordination polymers previously described.     

Dinuclear and layered copper 2-pyridylphosphonates with weak ferromagnetism observed in layer compound Cu(C5H4NPO3)

This paper reports the syntheses and structures of three new copper phosphonates based on 2-pyridylphosphonate, namely, Cu(C(5)H(4)NPO(3)H)2 (1), Cu3(OH)2(C(5)H(4)NPO(3))2.2H2O (2) and Cu(C(5)H(4)NPO(3)) (3). Compound 1 has a discrete dimeric structure in which the {CuO(4)N} square pyramids are linked by the {CPO(3)} tetrahedra through corner-sharing. The dimers are further connected into a chain through hydrogen bonds. In compound 2, edge-sharing {Cu(1)O(4)N} square pyramids and {Cu(2)O(4)} planes are found to form an infinite chain with composition {Cu(3)(mu-OH)(2)(mu-O)(4)}. Neighboring chains are linked by the phosphonate groups of the 2-pyridylphosphonate ligands, resulting in inorganic layers containing 4-, 8- and 12-membered rings. The pyridyl groups and the lattice water molecules occupy the inter-layer space. In compound 3, the {Cu(1)O(4)} and {Cu(2)O(2)N(2)} planes are each corner-shared with the {CPO(3)} tetrahedra, forming an inorganic layer containing 8- and 16-membered rings. The pyridyl groups reside between the layers. Crystal data for 1: space group P(-)1, a = 8.4045(19), b = 8.751(2), c = 10.632(2) A, alpha = 66.673(4), beta = 72.566(4), gamma = 70.690(4) degrees , V = 664.7(2) A(3), Z = 2. Crystal data for 2: space group P2(1)/c, a = 7.9544(17), b = 21.579(4), c = 5.0243(10) A, beta = 105.332(3) degrees , V = 831.7(3) A(3), Z = 2. Crystal data for 3: space group P2(1)/c, a = 4.7793(11), b = 15.319(3), c = 8.6022(19) A, beta = 97.156(4) degrees , V = 624.9(2) A(3), Z = 4. Magnetic measurements reveal that dominant antiferromagnetic interactions are propagated between the copper centers in compounds 1-3. For 3, spin canting is observed with a ferromagnetic transition occurring at 9 K.     

Octanuclear and nonanuclear supramolecular copper(II) complexes with linear "tritopic" ligands: structural and magnetic studies

The structures and magnetic properties of self-assembled copper(II) clusters and grids with the "tritopic" ligands 2poap (a), Cl2poap (b), m2poap (c), Cl2pomp (d), and 2pomp (e) are described [ligands derived by reaction of 4-R-2,6-pyridinedicarboxylic hydrazide (R = H, Cl, MeO) with 2-pyridinemethylimidate (a-c, respectively) or 2-acetylpyridine (d, R = Cl; e, R = H)]. Cl2poap and Cl2pomp self-assemble with Cu(NO(3))(2) to form octanuclear "pinwheel" cluster complexes [Cu(8)(Cl2poap-2H)(4)(NO(3))(8)].20H(2)O (1) and [Cu(8)(Cl2pomp-2H)(4)(NO(3))(8)].15H(2)O (2), built on a square [2 x 2] grid with four pendant copper arms, using "mild" reaction conditions. Similar reactions of Cl2pomp and 2pomp with Cu(ClO(4))(2) produce pinwheel clusters [Cu(8)(Cl2pomp-2H)(4)(H(2)O)(8)](ClO(4))(8).7H(2)O (3) and [Cu(8)(2pomp-2H)(4)(H(2)O)(8)](ClO(4))(8) (4), respectively. Heating a solution of 1 in MeOH/H(2)O produces a [3 x 3] nonanuclear square grid complex, [Cu(9)(Cl2poap-H)(3)(Cl2poap-2H)(3)](NO(3))(9).18H(2)O (5), which is also produced by direct reaction of the ligand and metal salt under similar conditions. Reaction of m2poap with Cu(NO(3))(2) produces only the [3 x 3] grid [Cu(9)(m2poap-H)(2)(m2poap-2H)(4)](NO(3))(8).17H(2)O (6) under similar conditions. Mixing the tritopic ligand 2poap with pyridine-2,6-dicarboxylic acid (picd) in the presence of Cu(NO(3))(2) produces a remarkable mixed ligand, nonanuclear grid complex [Cu(9)(2poap-H)(4)(picd-H)(3)(picd-2H)](NO(3))(9).9H(2)O (7), in which aromatic pi-stacking interactions are important in stabilizing the structure. Complexes 1-3 and 5-7 involve single oxygen atom (alkoxide) bridging connections between adjacent copper centers, while complex 4 has an unprecedented mixed micro-(N-N) and micro-O metal ion connectivity. Compound 1 (C(76)H(92)N(44)Cu(8)O(50)Cl(4)) crystallizes in the tetragonal system, space group I, with a = 21.645(1) A, c = 12.950(1) A, and Z = 2. Compound 2 (C(84)H(88)N(36)O(44)Cl(4)Cu(8)) crystallizes in the tetragonal system, space group I, with a = 21.2562(8) A, c = 12.7583(9) A, and Z = 2. Compound 4 (C(84)H(120)N(28)O(66)Cl(8)Cu(8)) crystallizes in the tetragonal system, space group I4(1)/a, with a = 20.7790(4) A, c = 32.561(1) A, and Z = 4. Compound 7(C(104)H(104)N(46)O(56)Cu(9)) crystallizes in the triclinic system, space group P, with a = 15.473(1) A, b = 19.869(2) A, c = 23.083(2) A, alpha = 88.890(2) degrees, beta = 81.511(2) degrees, gamma = 68.607(1) degrees, and Z = 2. All complexes exhibit dominant intramolecular ferromagnetic exchange coupling, resulting from an orthogonal bridging arrangement within each polynuclear structure.     

Synthesis and structural characterisation of the new K2NiF4-type phases, A2In0.5Sb0.5O4(A = Sr, Ba)

In this paper the synthesis and structural characterisation of two new K2NiF4-type phases, Ba2In(0.5)Sb(0.5)O4 and Sr2In(0.5)Sb(0.5)O4, are reported. These are the first examples of K2NiF4 compounds of general formula A2MIII(0.5)M'(V)(0.5)O4 with both 3+ and 5+ cations in the octahedral sites. Ba2In(0.5)Sb(0.5)O4 is shown to have a tetragonal cell [space group I4/mmm, a= 4.1651(1), c= 13.299(1) A] with an essentially disordered arrangement of In and Sb. In the case of Sr2In(0.5)Sb(0.5)O4, however, ordering of In and Sb is observed leading to an expanded unit cell [Pmcb, a= 5.7592(1), b= 5.7740(1), c= 12.543(1) A]. The results therefore show that varying the size of the alkaline earth cation has a pronounced effect on the ordering of In and Sb within the structure.