Photochemical synthesis, properties and X-ray crystal structure of tetrabutylammonium dodecamolybdophosphate heteropoly blue

The title heteropoly blue, (Bu4N)(6)H-10 [(PMo11MoO40)-Mo-VI-O-V](4) . H2O has been photochemically synthesized and characterized with elemental analysis, solid diffusion reflectance electronic spectra, CV, ESR, XPS, IR spectra, conductivity measurement and X-ray single crystal analysis. The crystallographic data for C96H218Mo48N6O169P4 are as follows: M-r = 8889.76, triclinic, P (1) over bar, a = 1.4142 (3) nm, b = 2.6027 (5) nm, c = 2.6403(5) nm, alpha = 113.96(3)degrees, beta = 90.05(3)degrees, gamma = 105.71(3)degrees, V = 8.481 (3) nm(3), Z = 1, D-c = 1.741 g/cm(3), F (000) = 4264, mu = 1.798 mm(-1). The X-ray crystal structure analysis reveals that there Is one independent molecule in the unit cell of the title heteropoly blue which contains four mixed-valence heteropoly anions, six tetrabutylammonium cations and one water molecule. Its molecular structure possesses a centrosymmetrical arrangement in the unit cell. The phosphorus atom is In the crystallographic inversion center of the heteropoly anion and the eight oxygen atoms surrounding central phosphorus atom comprise of a distorted hexahedron. Heteropolyanion has two equal sets of PO4 tetrahedron. The PO4 tetrahedron and the MoO6 octahedron in the polyanion are greatly distorted.

Hydrothermal synthesis and structure of a bi-capped Keggin polyoxoanion, [(As2AsMo8V4O40)-As-III-Mo-V-O-IV](5-)

The title compound, [NH3CH2CH2CH2NH2][NH3CH2CH2CH2NH3](2)[As-2(III) As-v Mo-8 V-4(IV) O-40] (.) 5H(2)O, was hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Crystal data: monoclinic, C2/c, a = 45.375(9) Angstrom, b = 11.774(2) Angstrom, c = 23.438(5) Angstrom, beta = 96.62(3)degrees. X-ray crystallographic study showed that the crystal structure was constructed by bi-capped alpha -Keggin fragments [(As2AsMo8V4O40)-As-III-Mo-v-O-IV](5-) polyoxoanion. (C) 2001 Elsevier Science B.V. All rights reserved.

Synthesis and crystal structure of a novel compound constructed from tris-(2, 2 '-bipy)ruthenium(II) and decatungstate

Self-assembly of tris-[2,2 ' -bipyridine]ruthenium(II) chloride with decatunstate produced a novel cation radical salt, [Ru(bpy)(3)](2)[W10O32] . 3DMSO. This is the first product of 2,2 ' -bipyridineruthenium(II)-polyoxometalates species. Crystal data: Monoclinic, P2(1)/c, a = 12.902(3) Angstrom, b = 21.487(3) Angstrom, c = 15.854(5) Angstrom, beta = 93.46(2)degrees, V = 4387(2) Angstrom (3), Z = 2, R-1 = 0.0599, wR2 = 0.1183. X-ray crystallographic study showed that the crystal structure was constructed by electyrostatic attraction and C-H . . .O hydrogen bonds between tris-[2,2 ' -bipyridine]ruthenium(II) and decatungstate polyanion. The tris-[2,2 ' -bipyridine]ruthenium molecules occupy cavities in the polyoxometalate lattice ordered along b-axis. (C) 2001 Elsevier Science B.V. All rights reserved.

Single crystal structure of form I syndiotactic poly(butene-1)

The structures of single crystals of syndiotactic poly(butene-1) in form I, produced by thin-film growth, are studied by transmission electron microscopy and electron diffraction. Bright-field electron microscopy observation shows that the single crystal exhibits a regular rectangular shape with the long axis along its crystallographic b-axis. Electron diffraction results indicate an isochiral C-centered packing of a-fold helical chains in an orthorhombic unit cell corresponding to the C222(1) space group, according to the model proposed in the literature. The differences with the polymorphic behavior of syndiotactic polypropylene concerning the formation and the stability of the isochiral mode of packing are outlined.

Photochemical synthesis and crystal structure of a charge transfer salt [HMDH2][(H2PMoMo11O40)-Mo-v]center dot 2AA center dot 3H(2)O center dot DMF

The title supramolecular compound, [HMDH2][(H2PMoMo11O40)-Mo-V] . 2AA . 3H(2)O . DMF (HMD = hexamethylene diamine; AA=acetaldehyde; DMF=N,N-dimethyl formamide), has been photochemically synthesized by using elemental analysis, IR, solid diffusion reflectance, electronic spectra, ESR spectra and X-ray single-crystal analysis. The crystallographic data: triclinic, P (1) over bar, a=14.092(2), b=14.347(3), c=14.358(3)Angstrom, alpha = 75.10(3), beta = 80.70(3), gamma = 80.73(3)degrees, V = 2746.6(10)Angstrom (3), Z = 2, M-r = 2081.68, D-c=2.517g/cm(3), F(000) =1970, mu (MoK alpha) =2.766mm(-1). The structure has been refined to R =0.0832 and wR=0.2638, by full-matrix least-squares method. The title compound is composed of hexamethylene diamine, two acetaldehyde molecules, three water molecules, one N,N-dimethylformamide and [(H2PMoMo11O40)-Mo-V](2-) heteropoly anion.

Synthesis and structure of a novel mononuclear tungsten (VI) citrato complex, (NH4)(3)[Li(H2O)(3)WO3(C6H4O7)]

The first mononuclear tungsten-citrato complex, (NH4)(3)[Li(H2O)(3)WO3(C6H4O7)] (1) has been prepared by the reaction of ammonium tetrathio tungstate and lithium citrate in CH3OH - H2O solution at pH 8.2. There are two crystallographically independent anions in the asymmetric crystallographic unit. The crystal structure of the title compound (triclinic, space group P (1) over bar, a = 6.901(1), b = 15.136(3), c = 16.107(3) Angstrom, alpha = 75.85(3), beta = 89.89(3), gamma = 89.97(3), V = 1631.4(6) Angstrom (3), R = 0.068, R-w = 0.1674 for 3878 reflections with I > 2 sigma (1)), reveals that in the compound a tungsten atom is coordinated to a fully deprotonated citrate as a tridentate ligand and three terminal oxygen atoms to form a distorted coordination octahedron.

Crystal structure of mixed sodium-potassium paradodecatungstate 6-hydrate

The crystal structure of K7Na3[H2W12O42]3 . 6H(2)O was determined by X-ray crystallography,and refined to R=0.0864 based on 7024 observed reflections (I>2 sigma(I)). The crystallographic parameters are a=11.755(2), b=13.0493(3), c=16.289(3) Angstrom; alpha=77.13(3)degrees, beta=82.92(3)degrees, gamma=89.65(3)degrees, triclinic, space group, P (1) over bar, V=2416.7(8) Angstrom(3), Z=2, M-r=3330.98, D-cal=4.578Mg/m(3), F(000)=2904; mu (MoK alpha)=29.170mm(-1), T=293K. Two independent polyanions are centered respectively at 1,1,1/2 and 1/2, 1/2, 0, approximately perpendicular to each other with dihedral angle between the equatorial planes of the molecules at 96 degrees. K+ and Na+ respectively occupy the clefts of the two discrete polyanions.

Structure, luminescence and magnetic properties of AgLnW(2)O(8) (Ln = Eu, Gd, Tb and Dy) compounds

Four new compounds AgLnW(2)O(8) (Ln = Eu, Gd, Tb and Dy) are prepared by solid-state reactions. They crystallize with a scheelite-related monoclinic symmetry. Infrared (IR) spectra show complicated absorption transitions in the region of 1000-400 cm(-1) that are similar to those of AgLnMo(2)O(8). Broad excitation and emission bands of the tungstate group are observed in AgGdW2O8 and AgTbW2O8 with a large Stokes shift, 12 573 and 12 387 cm(-1), respectively. Excitation and emission spectra of AgLnW(2)O(8) (Ln = Eu, Gd and Tb) show that energy transfer from the tungstate to EU3+, Gd3+ and Tb3+ occurs and that Eu3+ ions occupy a single crystallographic site with the C-2 Site symmetry. (C) 1997 Elsevier Science Ltd. All rights reserved.

Morphology and structure of poly(aryl ether ketone ketone) containing isophthaloyl moieties crystallized from dilute solution

Spherulites and lamellar single crystals of poly(aryl ether ketone ketone) containing isophthaloyl moieties (PEKK(I)) were obtained from dilute alpha-chloronaphthalene solution. The morphology and structure of the spherulites and single crystals were studied by electron microscopy and electron diffraction. The spherulites were found to consist of elongated lamellar branches that grow with the b crystallographic axis in the radial direction. Single crystals possess a similar habit, with b parallel to the long axis, a transverse, and c perpendicular to the lamellae plane. High-resolution images of the PEKK(I) crystals which show the perfection of and defects in the crystals, were obtained, and many defects or dislocations a,ere observed. (C) 1997 Elsevier Science Ltd.

Structure and luminescence properties of some new AgLnW(2)O(8) compounds

Three new compounds, AgLnW(2)O(8) (Ln(3+)=Eu, Gd or Tb), have been prepared by a solid-state reaction and crystallize with a scheelite-related monoclinic symmetry. Their IR spectra show absorption transitions in the region 1000-400 cm(-1) similar to KLnW(2)O(8). Broad excitation and emission bands of the tungstate group with a large Stokes shift (12573 cm(-1)) are observed in AgGdW2O8. Excitation and emission spectra of AgLnW(2)O(8) (Ln=Eu or Tb) show that energy transfer from tungstate to Eu and Tb occurs and that Eu3+ ions occupy a unique crystallographic site with C-2 site symmetry.

General expression for probabilistic estimation of multiphase structure invariants in the case of a native protein and multiple derivatives. Application to estimates of the three-phase structure invariants

Concise probabilistic formulae with definite crystallographic implications are obtained from the distribution for eight three-phase structure invariants (3PSIs) in the case of a native protein and a heavy-atom derivative [Hauptman (1982). Acta Cryst. A38, 289-294] and from the distribution for 27 3PSIs in the case of a native and two derivatives [Fortier, Weeks & Hauptman (1984). Acta Cryst. A40, 646-651]. The main results of the probabilistic formulae for the four-phase structure invariants are presented and compared with those for the 3PSIs. The analysis directly leads to a general formula of probabilistic estimation for the n-phase structure invariants in the case of a native and m derivatives. The factors affecting the estimated accuracy of the 3PSIs are examined using the diffraction data from a moderate-sized protein. A method to estimate a set of the large-modulus invariants, each corresponding to one of the eight 3PSIs, that has the largest \Delta\ values and relatively large structure-factor moduli between the native and derivative is suggested, which remarkably improves the accuracy, and thus a phasing procedure making full use of all eight 3PSIs is proposed.

The reactivity of lanthanide alkyl compounds with phenylacetylene: Synthesis and structure of [(Bu(t)Cp)(2)LnC CPh](2) (Ln=Nd, Gd)

[(Bu(t)Cp)(2)LnCH(3)](2) (Ln = Nd, Gd) react with PhC=CH to form the dimeric alkynide-bridged complexes [(Bu(t)Cp)(2)LnC=CPh](2) [Ln = Nd (I), Gd (II)]. Both compounds crystallized from toluene in the monoclinic space group C2/c. The two complexes are homologous, composed of asymmetric metal-alkynide bridges with Nd-C, Gd-C (alkynide) bond lengths of 2.602(4), 2.641(5) (I) and 2.532(6), 2.601(7) Angstrom (II), respectively. The average Nd-C (ring) and Gd-C (ring) distances are 2.746(13) and 2.703(19)Angstrom.

WAXD and SAXS study on gamma-radiation damage to polyamide-1010 crystal structure

In the present work we attempt to settle the controversy on the district wherein the radiation induced reaction preferentially occurs through examining the structural changes of the irradiated polyamide-1010 specimens on both the crystallographic and the supermolecular level by using WAXD and SAXS techniques. Experimental results indicated that the chain crosslinking and scission of the irradiated specimens occur mainly in the amorphous region and on the crystal surface (or interphase), and extend into the inner portion of the crystal with increasing radiation dose.

THE SYNTHESIS AND CRYSTAL-STRUCTURE OF [LA(OH2)(5)(PHEN)(2)]CL-3-CENTER-DOT-4H(2)O-CENTER-DOT-PHEN

[La(OH2)(5)(phen)(2)]Cl-3 4H(2)O.phen is centric, Pnna, with a = 19.946(7), b = 16.458(5), c = 12.207(4)Angstrom and D-calc = 1.57 g cm(-3) for Z = 4. The La(III) ion resides on a crystallographic twofold axis and is coordinated to four nitrogen atoms (fr