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1.
The crystal structure of K2Cu3(As2O6)2 was determined from single-crystal X-ray data by a direct method strategy and Fourier summations [a = 10.359(4) Å, B = 5.388(2)Å, C = 11.234(4) Å, β = 110.48(2)°; space group C2/m; Z = 2; Rw = 0.025 for 1199 reflections up to sin /λ = 0.81 Å−1]. In detail, the structure consists of As(V)O4 tetrahedra and As(III)O3 pyramids linked by a common O corner atom to [As(V)As(III)O6]4− groups with symmetry m. The bridging bonds As(V)---O [1.749(3) Å] and As(III)---O [1.838(2) Å] are definitely longer than the other As(V)---O bonds [mean 1.669 Å] and As(III)---O bonds [1.764(2) Å, 2×]. The angle As(V)---O---As(III) is 123.0(1)°. The Cu atoms are [4 + 2]- and [4 + 1]-, and the K atom is [9]-coordinated to oxygen atoms. The As2O6 groups and the Cu coordination polyhedra are linked to sheets parallel to (001). These sheets are connected by the K atoms. Single crystals of K2Cu3(As2O6)2 suitable for X-ray work were synthesized under hydrothermal conditions.  相似文献   

2.
The influence of the substituent at the C2 position on the hydrogen‐bonding patterns is compared for a series of five related compounds, namely (±)‐3‐exo,6‐exo‐dibromo‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carbonitrile, C8H8Br2N2O3, (II), (±)‐3‐exo,6‐exo‐dibromo‐6‐endo‐nitro‐5‐exo‐phenylbicyclo[2.2.1]heptan‐2‐endo‐ol, C13H13Br2NO3, (III), (±)‐methyl 3‐exo,6‐exo‐dibromo‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carboxylate, C9H11Br2NO5, (IV), (±)‐methyl 3‐exo,6‐exo‐dibromo‐7‐diphenylmethylidene‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carboxylate, C22H19Br2NO5, (V), and (±)‐methyl 3‐exo,6‐exo‐dibromo‐5‐endo‐hydroxy‐3‐endo‐nitro‐7‐oxabicyclo[2.2.1]heptane‐2‐exo‐carboxylate, C8H9Br2NO6, (VI). The hydrogen‐bonding motif in all five compounds is a chain, formed by O—H...O hydrogen bonds in (III), (IV), (V) and (VI), and by O—H...N hydrogen bonds in (II). All compounds except (III) contain a number of Br...Br and Br...O halogen bonds that connect the chains to each other to form two‐dimensional sheets or three‐dimensional networks. None of the compounds features intramolecular hydrogen bonding between the alcohol and nitro functional groups, as was found in the related compound (±)‐methyl 3‐exo,6‐exo‐dichloro‐5‐endo‐hydroxy‐3‐endo‐nitrobicyclo[2.2.1]heptane‐2‐exo‐carboxylate, (I) [Boeyens, Denner & Michael (1984b). J. Chem. Soc. Perkin Trans. 2, pp. 767–770]. The crystal structure of (V) exhibits whole‐molecule disorder.  相似文献   

3.
Chemical preparation and crystallographic data are specified for thallium polyphosphate. TlPO3 crystallizes in the monoclinic system, space group P21/n, with the following unit-cell parameters: a = 12.270(7) Å; b = 4.263(2) Å; c = 6.328(4) Å; β = 96°.72(3); Z = 4. This compound is isotypic with two previously described polyphosphates, namely RbPO3 and CsPO3.  相似文献   

4.
In the presence of HSO3F/Ac2O in CH2CL2, 2-exo- and 2-endo-cyano-5,6-exo-epoxy-7-oxabicyclo[2.2.1]hept-2-yl acetates ( 6a , b ) gave products derived from the epoxide-ring opening and a 1,2-shift of the unsubstituted alkyl group (σ bond C(3)–C(4)). In contrast, under similar conditions, the 5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ( 6c ) gave 5-oxo-2-oxabicyclo[2.2.1]heptane-3,7-diyl diacetates 20 and 21 arising from the 1,2-shift of the acyl group. Acid treatment of 5,6-exo-epoxy-2,2-dimethoxy-7-oxabicyclo[2.2.1]heptane ( 6d ) and of 5,6-exo-epoxy-2,2-bis(benzyloxy)-7-oxabicyclo[2.2.1]heptane ( 6e ) gave minor products arising from epoxide-ring opening and the 1,2-shift of σ bond C(3)–C(4) and major products ( 25 , 29 ) arising from the 1,3-shift of a methoxy and benzyloxy group, respectively. Under similar conditions, 5,6-exo-epoxy-2,2-ethylenedioxy-7-oxabicyclo[2.2.1]heptane ( 6f ) gave 1,1-(ethylenedioxy)-2-(2-furyl)ethyl acetate ( 32 , major) and a minor product 33 , arising from the 1,2-shift of σ bond C(3)–C(4). The following order of migratory aptitudes for 1,2-shifts toward electron-deficient centers has been established: acyl > alkyl > alkyl α-substituted with inductive electron-withdrawing groups. This order is valid for competitive Wagner-Meerwein rearrangements involving equilibria between carbocation intermediates with similar exothermicities.  相似文献   

5.
Epoxidation of (?)-(1R,2R,4R)-2-endo-cyano-7-oxabicyclo[2.2.1]hept-5-en-2-exo-yl acetate ((?)-5) followed by saponification afforded (+)-(1R,4R,5R,6R)-5,6-exo-epoxy-7-oxabicyclo[2.2.1]heptan-2-one ((+)-7). Reduction of (+)-7 with diisobutylaluminium hydride (DIBAH) gave (+)-1,3:2,5-dianhydroviburnitol ( = (+)-(1R,2R,3S,4R,6S)-4,7-dioxatricyclo[3.2.1.03,6]octan-2-ol; (+)-3). Hydride reductions of (±)-7 were less exo-face selective than reductions of bicyclo[2.2.1]heptan-2-one and its derivatives with NaBH4, AlH3, and LiAlH4 probably because of smaller steric hindrance to endo-face hydride attack when C(5) and C(6) of the bicyclo-[2.2.1]heptan-2-one are part of an exo oxirane ring.  相似文献   

6.
A novel thioantimonate(III) [(CH3NH3)1.03K2.97]Sb12S20·1.34H2O was synthesized hydrothermally. It crystallizes in space groupP , witha=11.9939(7) Å,b=12.8790(8) Å,c=14.9695(9) Å,α=100.033(1)°,β=99.691(1)°,γ=108.582(1)°,V=2095.3(2) Å3, andZ=2. The structure is determined from single crystal X-ray diffraction data collected at room temperature and refined toR(F)=0.037. In the crystal structure, each Sb(III) atoms has short bonds (2.37–2.58 Å) to three S atoms. The pyramidal [SbS3] groups share common S atoms forming two types of centrosymmetric [Sb12S20] rings with the same topology. These rings are interconnected by weaker Sb–S bonds (2.92–3.29 Å) into 2-dimensional layers. Adjacent layers are parallel with K+and CH3NH+3ions and H2O molecules located between them. Variation of bond valence sums calculated for the Sb(III) cations is found to be correlated with the coordination geometry. This is interpreted as due to the stereochemical activity of their lone electron pairs.  相似文献   

7.
A new mixed Mo/Ni/Ti heteropoly compound [C5H5NH]5 [(NiOH)2Mo10O36(PO4)Ti2] has been hydrothermally synthesized and structurally determined by the single-crystal X-ray diffraction. Black prismatic crystals crystallize in the monoclinic system, space group P2(1)/n, a=11.2075(2), b=37.8328(5) c=13.0888(1) Å, β=101.4580(10)°, M=2276.13, V=5439.19(13) Å3, Z=4. Data were collected on a Siemens SMART CCD diffractometer at 293(2) K in the range of 1.68<θ<25.09° using the ω-scan technique (λ=0.71073 Å R(F)=0.0872 for 9621 reflections). The title compound contains a trimetal heteropolyanion polymer and “trans-titanium”-bridging pseudo-Keggin fragments linked to a chain.  相似文献   

8.
The crystal structure of dilithium piperazinium(2+) selenate tetrahydrate has been solved; this substance crystallizes in the triclinic space group , a=7.931(2) Å, b=7.974(2) Å, c=7.991(2) Å, α=106.99(2)°, β=101.83(2)°, γ=119.28(2)° Z=1, R=0.0280 for 1489 observed reflections. A similar compound, dilithium N,N′-dimethylpiperazinium(2+) selenate tetrahydrate crystallizes in a monoclinic system with space group P21/c and lattice parameters a=7.338(1) Å, b=8.792(2) Å, c=12.856(1) Å, β=92.04(2)°, Z=2, R=0.0334 for 1462 observed reflections. Both structures are centrosymmetric with center of symmetry in the center of eight membered ring formed with two SeO4 tetrahedra and two LiO4 tetrahedra connected through tops. The two remaining oxygens on each Li atom come from water molecules. The FTIR and FT Raman spectra of both natural and N,O-deuterated substances have been measured and studied. The thermoanalytical properties were studied using TG, DTG and DTA methods in the temperature range 293–873 K for piperazinium derivative and in the range 293–523 K for dimethylpiperazinium derivative. DSC measurements were carried out in the temperature range 95–343 K. No phase transition was found in this temperature region for either of the compounds.  相似文献   

9.
The hydrothermal synthesis, crystal structure and some properties of a zinc phosphite with a neutral cluster, [Zn(2,2′-bipy)]2(H2PO3)4, are reported. This compound crystallizes in the triclinic system of space group P-1 (No. 2), a=8.3067(5) Å, b=8.9545(4) Å, c=10.0893(6) Å, α=95.448(2)°, β=99.7530(10)°, γ=103.461(2)°, V=712.23(7) Å3, Z=1. The cluster consists of 4-membered rings formed by alternating ZnO3N2 square pyramids and H2PO3 pseudo pyramids, with two “hanging” H2PO3 groups attached to each of the Zn centers. The clusters are linked together by extensive multipoint hydrogen bonding involving the phosphite units to form a sheet-like structure. This compound represents the first example of zinc phosphite with P---OH bonds. An intense photoluminescence was observed from this compound upon photoexcitation at 388 nm.  相似文献   

10.
The crystal structures of Sr10Ga6O19 and Sr3Ga2O6 have been characterized using X-ray diffraction techniques. In the case of Sr10Ga6O19, the structure was determined from a single crystal diffraction data set collected at room conditions and refined to a final R index of 0.061 for 3471 observed reflections (I>2 σ(I)). The compound is monoclinic with space group C12/c1 (a=34.973(4) Å, b=7.934(1) Å, c=15.943(2) Å, β=103.55(1)°, V=4300.7(6) Å3, Z=8, Dcalc=4.94 g/cm3, μ(Mo)=32.04 mm−1) and can be classified as an oligogallate. It is the first example of an inorganic compound where six [TO4]-tetrahedra of only one chemical species occupying the tetrahedral centres are linked via bridging oxygen atoms to form [T6O19] groups. The hexamers are not linear, but highly puckered. Eleven symmetrically different Sr cations located in planes parallel (100) crosslink between the oligo-groups. They are coordinated by six to eight oxygen ligands. The structure of Sr3Ga2O6 has been refined from powder diffraction data using the Rietveld method (space group Pa , a=16.1049(1), V=4177.1(1) Å3, Z=24, Dcalc=4.75 g/cm3). The compound is isostructural with tricalcium aluminate and contains highly puckered, six-membered [Ga6O18]18− rings. The rings are linked by strontium cations having six to nine nearest oxygen neighbors.  相似文献   

11.
Investigation into the synthesis of reduced vanadium phosphate has led to the formation of a new form of the barium vanadium (III) pyrophosphate compound β-BaV2(P2O7)2. It is a polymorph of the previously known BaV2(P2O7)2, which is now labeled as the α-phase. The title compound crystallizes in the P-1 (No. 2) space group with a = 6.269(1) Å, b = 7.864(3) Å, c = 6.1592(9) Å, α = 101.34(2)°, β = 105.84(1)°, and γ = 96.51(2)°. The structure consists of corner-shared VO6 octahedra and PO4 tetrahedra that are connected in V-O-P-O-V and V-O-P-O-P-O-V bonding arrangements. This interesting three-dimensional framework is characterized by seven types of intersecting tunnels, three of which are occupied by the barium cation, while the others are empty. It is important to know that one of the empty tunnels has a relatively large window with a minimum diagonal distance of 4.41 Å, which facilitates a possible framework for a lithium ion insertion reaction. The barium atom has a 10-coordination sphere, BaO10, in which the oxygen atoms can be viewed as forming two intersecting pseudohexagonal planes. β-BaV2(P2O7)2 appears to form at a relatively higher temperature than its polymorph, α-BaV2(P2O7)2. A detailed structural analysis and structural comparison with the α-phase, as well as a brief comparison with SrV2(P2O7)2, are presented.  相似文献   

12.
The structure of [Pd(OAc){CH2C6H4P-t-Bu(o-tolyl)}]2 has been determined from three dimensional X-ray diffractometer data. The compound crystallizes in the space group P , Z = 2, with a reduced triclinic unit cell a = 12.989, b = 15.643, c = 20.325 Å, α = 130.85, β = 117.91, γ = 94.08°. A least squares refinement of atomic positional and thermal parameters, based on 5436 observed reflections has converged to discrepancy indices, R1 and R2, of 0.044 and 0.058.The structure consists of independent dimeric molecules packed with cyclohexane molecules of crystallization. [o-(t-butyl-o-tolylphosphino)benzyl]palladium(II) fragments are bridged by the two acetate groups so that each palladium has a slightly distorted planar coordination; the molecule has approximate C2 symmetry with a Pd…Pd non-bonding distance of 3.413(1) Å. The mean Pd-P and Pd-C bond lengths are 2.204(2) and 2.033(5) Å respectively, other mean distances being Pd-O 2.13(1), C-C(methyl) 1.497(4), O-C(acetate) 1.247(6). C-C(benzyl) 1.497(7) Å. The solvated cyclohexane molecules are disordered.  相似文献   

13.
The crystal structure of a new oxide, La2RuO5, was determined ab initio using conventional laboratory X-ray powder diffraction. Combining X-ray and electron diffraction techniques, we found that the new phase crystallized in the monoclinic system with the space group P21/c (SG no.14) and the cell parameters a=9.1878(2) Å, b=5.8313(2) Å, c=7.9575(2) Å and β=100.773(2)° (V=418.8 Å3, Z=4). The structural determination with the Patterson method and Fourier difference syntheses and the final Rietveld refinement were performed by means of the JANA2000 program. The structure is built up from the regular stacking of a two octahedra thick [LaRuO4] zigzag perovskite slab and an original 3.4 Å thick [LaO] slab which constitutes the key feature of this new structure.  相似文献   

14.
15.
The crystal structures of 1,4-diazabicyclo[2.2.2]octane (dabco)-templated iron sulfate, (C6H14N2)[Fe(H2O)6](SO4)2, were determined at room temperature and at −173 °C from single-crystal X-ray diffraction. At 20 °C, it crystallises in the monoclinic symmetry, centrosymmetric space group P21/n, Z=2, a=7.964(5), b=9.100(5), c=12.065(5) Å, β=95.426(5)° and V=870.5(8) Å3. The structure consists of [Fe(H2O)6]2+ and disordered (C6H14N2)2+ cations and (SO4)2− anions connected together by an extensive three-dimensional H-bond network. The title compound undergoes a reversible phase transition of the first-order at −2.3 °C, characterized by DSC, dielectric measurement and optical observations, that suggests a relaxor–ferroelectric behavior. Below the transition temperature, the compound crystallizes in the monoclinic system, non-centrosymmetric space group Cc, with eight times the volume of the ambient phase: a=15.883(3), b=36.409(7), c=13.747(3) Å, β=120.2304(8)°, Z=16 and V=6868.7(2) Å3. The organic moiety is then fully ordered within a supramolecular structure. Thermodiffractometry and thermogravimetric analyses indicate that its decomposition proceeds through three stages giving rise to the iron oxide.  相似文献   

16.
Two novel heterometallic trinuclear incomplete cubane-like clusters [(CH3CH2)4N][{M2CuS4}(edt)2(PPh3)] (M = Mo, W) have been synthesized by reaction of [(CH3CH2)4N]2[M2S4(edt)2] (M = Mo, W) with Cu(PPh3)2(dtp) [where edt is 1,2-ethane-dithiolato ligand, dtp is S2P(OCH2CH3)2]. The two crystals are isomorphous in space group P1 (No. 1). The unit cell contains two independent molecules, but the two discrete anions have the same orientation for the PPh3 ligands along one axis so the space group is undoubtedly non-centrosymmetric. The discrete anion contains two edt ligands and one PPh3 ligand attached to one incomplete cubane-like cluster core {M2CuS4}3+ (M = Mo, W). The bond lengths of Mo---Mo[W---W] and the two Mo---Cu[W-Cu] are 2.852(2)[2.844(1)], 2.802(2)[2.765(3)], 2.760(2)[2.762(3)] Å, respectively. The M 2S4(edt)2 (M = Mo, W) moiety remains almost unchanged, except that for the compound 1 the Mo=S double bond length elongates from av. 2.10 to av. 2.165 Å. The title clusters provide a new type of unsymmetric μ2-bridging sulphido ligand. The incomplete cubane-like cluster core {Mo2CuS4}3+ of compound 1 is distorted because the two Cu---μ2---S bond lengths are significantly different (2.313 Å and 2.409 Å), but the core {W2CuS4}3+ of compound 2 has approximately Cs symmetry. The IR spectra of the two title clusters and two starting materials are assigned.  相似文献   

17.
Two new potassium vanadium phosphates have been prepared and their structures have been determined from analysis of single crystal X-ray data. The two compounds, K3(VO)(V2O3) (PO4)2(HPO4) and K3(VO)(HV2O3)(PO4)2(HPO4), are isostructural, except for the incorporation of an extra hydrogen atom into the nearly identical frameworks. The structures consist of a three-dimensional network of [VO]n chains connected through phosphate groups to a [V2O3] moiety. Magnetic susceptibility experiments indicate that in the case of the di-hydrogen compound, there are no significant magnetic interactions between the three independent vanadium (IV) centers. Crystal data: for K3(VO)(V2O3)(PO4)2 (HPO4), Mr = 620.02, orthorhombic space group Pnma (No. 62), a = 7.023(4) Å, b = 13.309(7) Å, c = 14.294(7) Å, V = 1336(2) Å3, Z = 4, R = 5.02%, and Rw = 5.24% for 1238 observed reflections [I > 3σ(I)]; for K3(VO)(HV2O3)(PO4)2(HPO4), Mr = 621.04, orthorhombic space group Pnma (No. 62), a = 6.975(3) Å, b = 13.559(7) Å, c = 14.130(7) Å, V = 1336(1) Å3, Z = 4, R = 6.02%, and Rw = 6.34% for 1465 observed reflections [I > 3σ(I)].  相似文献   

18.
Lewis-base mediated fragmentation of polymeric nickel(II) fumarate and oxalate are attempted using chelating σ-donor diamines like ethylenediamine (en) and 1,3-diaminopropane (dap) in various conditions which yielded [Ni(en)3](fum)·3H2O (1), [Ni(en)3](ox) (2), [Ni(dap)2(fum)] (3) and [Ni(dap)(ox)]·2H2O (4). While 1 and 2 are molecular products each containing octahedral [Ni(en)3]2+ moieties and the anionic dicarboxylate species, 3 and 4 are dap-incorporated polymeric products. The fumarate derivative 1 containing [Ni(en)3]2+ moieties crystallizes in the monoclinic space group C2/c with a = 17.899(4) Å, b = 11.747(2) Å, c = 10.748(2) Å, β = 125.59(3)°, V = 1837.7(6) Å3, Z = 4, while the oxalate analogue 2 is seen to be in the trigonal space group P−31c with a = 8.8770(13) Å, b = 8.8770(13) Å, c = 10.482(2) Å, γ = 120°, V = 715.3(2) Å3, Z = 2. The octahedral [Ni(en)3] units in both 1 and 2 are seen to be strongly H-bonded to the dicarboxylate moieties through the coordinated en units leading to a three-dimensional network. However, in 1 the water molecules also take part in the H-bonding and contribute to the overall 3D structure. In both 1 and 2 the crystal packing is done with the [Ni(en)3]2+ units with absolute configuration Λ(δδδ) and its mirror conformer with Δ configuration in exactly equal numbers. Spectral (IR and UV–Visible) and magnetic measurements were carried out and some of the ligand-field parameters like Dq, B and β were evaluated for all the four compounds. These values suggest the presence of octahedrally coordinated nickel(II) in all the four complexes. Spectral data suggest that 3 has the two chelating dap moieties and the fumarate coordinated in η1 form through both its carboxylate moieties while 4 has one chelating dap and the oxalate moiety coordinated in η4-bis-chelating form. Though both 1 and 2 are made of the same type of [Ni(en)3]2+ units their thermograms give entirely different thermal features; 1 showing three clearly successive and step-wise dissociation of each en unit while 2 having a combined loss of two en units in the first thermal step. The relevant thermodynamic and kinetic parameters like Ea and ΔS also could be evaluated for various thermal steps for the compounds 14 using Coats–Redfern equation.  相似文献   

19.
Three rare earth compounds, KEu[AsS4] (1), K3Dy[AsS4]2 (2), and Rb4Nd0.67[AsS4]2 (3) have been synthesized employing the molten flux method. The reactions of A2S3 (A = K, Rb), Ln (Ln = Eu, Dy, Nd), As2S3, S were accomplished at 600 °C for 96 h in evacuated fused silica ampoules. Crystal data for these compounds are: 1, monoclinic, space group P21/m (no. 11), a = 6.7276(7) Å, b = 6.7190(5) Å, c = 8.6947(9) Å, β = 107.287(12)°, Z = 2; 2, monoclinic, space group C2/c (no. 15), a = 10.3381(7) Å, b = 18.7439(12) Å, c = 8.8185(6) Å, β = 117.060(7)°, Z = 4; 3, orthorhombic, space group Ibam (no. 72), a = 18.7333(15) Å, b = 9.1461(5) Å, c = 10.2060(6) Å, Z = 4. 1 is a two-dimensional structure with 2[Eu(AsS4)] layers separated by potassium cations. Within each layer, distorted bicapped trigonal [EuS8] prisms are linked through distorted [AsS4]3− tetrahedra. Each Eu2+ cation is coordinated by two [AsS4]3− units by edge-sharing and bonded to further two [AsS4]3− units by corner-sharing. Compound 2 contains a one-dimensional structure with 1[Dy(AsS4)2]3− chains separated by potassium cations. Within each chain, distorted bicapped trigonal prisms of [DyS8] are linked by slightly distorted [AsS4]3− tetrahedra. Each Dy3+ ion is surrounded by four [AsS4]3− moieties in an edge-sharing fashion. For compound 3 also a one-dimensional structure with 1[Nd0.67(AsS4)2]4− chains is observed. But the Nd position is only partially occupied and overall every third Nd atom is missing along the chain. This cuts the infinite chains into short dimers containing two bridging [As4]3− units and four terminal [AsS4]3− groups. 1 is characterized with UV/vis diffuse reflectance spectroscopy, IR, and Raman spectra.  相似文献   

20.
A new hybrid inorganic–organic magnetic semiconductor [Ni(bipy)3Pb2I4.84Cl1.16·DMF]n (bipy=2,2′-bipyridine) containing novel one-dimensional mixed-halide anion of lead(II) was synthesized by reactions of PbI2, NaI, NiCl2 and bipy in DMF solution, and structurally characterized by single-crystal X-ray diffraction. It crystallizes in the space group C2/c with a=29.260(8) Å, b=15.602(4) Å, c=23.695(6) Å, β=126.815(°), Z=8, V=8660(4) Å3 and consists of a magnetic cation [Ni(bipy)3]2+ in addition to one-dimensional mixed-halide anion, which is built up of face-sharing [PbX6] octahedra. Of the seven crystallographically independent halide sites in this anion, one and five are occupied by Cl and I, respectively, the remaining one has mixed-iodide and -chloride occupancy. The title yellow compound has an optical bandgap of 2.59 eV, and the variable-temperature magnetic susceptibility measurement indicates paramagnetic behavior.  相似文献   

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