117 resultados para Youth center


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Reaction of thiamine or thiamine monophosphate (TMP) with K2Pt(NO2)(4) afforded a metal complex, Pt(thiamine)(NO2)(3) (1), and two salt-type compounds, (H-thiamine)[Pt(NO2)(4)]. 2H(2)O (2) and (TMP)(2)[Pt(NO2)(4)]. 2H(2)O (3), which were structurally characterized by X-ray diffraction. In 1, the square-planar Pt2+ ion is coordinated to the pyrimidine N(1'), a usual metal-binding site, and three NO2- groups. The thiamine molecule exists as a monovalent cation in 1 and a divalent cation in 2 while the TMP molecule is a monovalent cation in 3. In each compound, thiamine or TMP adopts the usual F conformation and forms two types of host-guest-like interactions with anions, which are of the bridging forms, C(2)-H . . . anion . . . pyrimidine-ring and N(4'1)-H(...)anion(...)thiazolium-ring. In 3, there is an additional anion-bridging interaction between the pyrimidine and thiazolium rings of TMP, being of the form C(6')-H . . . anion . . . thiazolium-ring. The salts 2 and 3 show similar hydrogen-bonded cyclic dimers of thiamine or TMP between which the anions are held. Results are compared with those of the other thiamine-platinum complexes. (C) 2001 Elsevier Science B.V. All rights reserved.

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A novel three-dimensional fluorinated gallium phosphate has been hydrothermally,synthesized by using diethylenetriamine as an organic structure-directing agent. X-ray single crystal structure analysis indicates this compound crystallizes in the orthorhombic space group P-bca, a = 1. 605 6 (7) nm, b = 1.011 4 (4) nm, c=1. 854 6(5) nm, V=3. 011 6(19) nm(3), Z=4. The three-dimensional framework based on linkage of corner-sharing polyhedron PO4, GaO4F and GaO4F2 delimit ten-ring channels along b axis in which the triply protonated amines are located serving as charge compensating guests and supporters.

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The title compound, [H3PMo12O40][CO(NH2)(2)](3). 5H(2)O, was synthesized and characterized by IR, C-13 NMR and X-ray diffraction. This is the first example of a urea-heteropoly acid species. Crystal data: monoclinic, C2/c, a = 17.790(4) Angstrom, b = 17.158(3) Angstrom, e = 25.512(5) Angstrom, beta = 100.65(3)degrees, V = 8514(3) Angstrom (3), Z = 6, R-1 = 0.0437, wR2 = 0. 1092. In the unit cell, the urea molecules occupy cavities in the polyoxometalate lattice ordered along b-axis. Water molecules occupy the space left by polyoxometalates, and urea. Polyoxometalate O atoms, the N atoms of urea and O atoms of water molecules are involved in hydrogen bonding. (C) 2001 Elsevier Science B.V. All rights reserved.

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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.

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(2,4-C7H11)(2)Yb . DME was synthesized by the reaction of YbCl3 with K(2,4-C7H11)(2,4-dimethylpentadienyl potassium), and the single crystal X-ray diffraction showed that the complex exists in a cis- staggered conformation. Thf crystal of the compound belongs to the monoclinic space group P2(1)/n with a = 0.675 2 (1) nm, b = 1.490 6 (1) nm, c = 1.529 3 (2) nm, beta = 97.55 (2)degrees, V = 1.977 79 (4) nm(3), Z = 4, F(000) = 735.8 e, mu = 49.49 cm(-1), R = 0.033 and R-w = 0.032. The title complex can be used as a catalyst for the polymerization of methyl methacrylate (MMA).

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The novel amino-acid-containing polyoxometalate Ka(6) [Cu(Ala)(2) (H2O)(2)](2) [Cu-4 (H2O)(2) . (AsW9O34)(2)] . 16H(2)O was synthesized from the reaction of K-10[Cu-4(H2O)(2)(AsW9O34)(2)] . 20H(2)O with beta -alanine, Its structure has been determined by single crystal X-ray diffraction. It crystallizes in the triclinic space group P (1) over bar, with a=1. 196 3(2) nm, b=1. 536 5(3) nm, c=1. 591 4(3) nm, alpha =93. 97(3)degrees, beta= 110. 88(3)degrees, gamma =101. 07(3)degrees, V=2. 651 8(9) nm(3) and Z=1. Least-squares refinement of the structure leads to R and R-w factors of 0. 067 3 and 0. 162 8, respectively. An unusual structural feature of the compound is that the polyanion [Cu-4(H2O)(2) (AsW9O34)](10-) is linked with the amino-acid complex of Cu2+ by a mu -oxygen atom.

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In this paper we describe the moleculare and crystal structures of the Na-3[Hg( II )(edta)Cl] . 6H(2)O (edta=ethylenediamine-N,N,N',N'-tetraacetate). The crystal data are as follows: orthorhombic, a=8. 083 (2) Angstrom , b=13. 870(3) Angstrom , c=38. 617(5) Angstrom , v=4329. 4 (13) Angstrom(3) , Z=8, Dc= 1. 798 g . cm(-3), mu=5. 564 mm(-1), P(000)=2280, R=0. 0317 and R-w=0. 0731 for 3883 unique reflections. In complex, the complex anion [Hg ( II ) (edta)Cl](3-) has a seven-coordination structure like a mono-capped trigonal-prism (C-2v-MTP) in which the edta(4-) acts as a hexadentate ligand with four O atoms and two N atoms and a Cl- caps a quadrilateral face as a seventh ligand. It can be known that the Hg2+ which has a d(10) electronic structure can form a high-coordinate compound with a hexadentate ligand (edta) because it has a big ionic radius.

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A novel heteropoly tungstophosphates, H-8[P4W14O58Na4(H2O)(20)] . 16H(2)O, was synthesized by hydrothermal method and characterized by elemental analysis, IR spectrum and single-crystal X-ray structure analysis. The thermal stability of the compound was investigated by using TG-DTA. The crystal is triclinic system with space group P (1) over bar, a = 1. 137 9(2) nm, b=1. 363 2(3) nm, c=1. 627 1(3) nm; alpha=78. 20(3)degrees, beta=71, 20(3)degrees, gamma= 71. 62(3)degrees; V = 2. 252 5(8) nm(3), Z=1, M-r= 4 374. 38, D-c = 3. 225 mg/cm(3), mu = 18. 007 mm(-1), F(000)=1 972, R=0. 074 2, R-w=0. 200 4. The result of structure analysis shows that the anion of the compound consists of two PW7O29Na2(H2O)(10) subunits and two linked phosphorous atoms. A kind of microporous with size of 0. 661 4 nm X 0. 318 9 nm was formed in the crystal structure.

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A manganese molybdenum phosphate, (NH3CH2CH2NH3)(10)(H3O)(3)(H5O)Na-2[MnMo12O24(OH)(6) (PO4)(4)(PO3OH)(4)][MnMo12O24 (OH)(6)(PO4)(6)(PO3OH)(2)]. 9H(2)O, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. The structure of this compound may be considered to be two [Mo6O12(OH)(3)(PO4)(2)(HPO4)(2)](7-) units bonded together by a manganese atom, although several P-O groups are not protonated on account of coordination to a Na+ cation. One-dimensional tunnels were formed in the solid. A probe reaction of the oxidation of acetaldehyde with H2O2 using this compound as catalyst was carried out in a liquid-solid system, showing that the manganese molybdenum phosphate has high catalytic activity in the reaction.

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A nickel molybdenum phosphate, (NH3CH2CH2NH3)(4).(NH3CH2CH2NH2). Na .[Ni2Mo12O30(PO4)(HPO4)(4)(H2PO4)(3)]. 6H(2)O, invoicing molybdenum present in V oxidation, has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. Deep brown-red crystals are formed in the triclinic system, space group P (1) over bar, a = 12,011(2), b = 14,612(3), c = 21.252(4) Angstrom, alpha = 80.54(2)degrees, beta = 83.10(2)degrees, gamma = 76.29(2)degrees, V = 3561.4(12) Angstrom(3), Z = 2, lambda(MoK alpha) = 0.71073 Angstrom (R(F) = 0.0529 for 9880 reflections), Data mere collected on a Siemens P4 diffractometer at 20 degrees C in the range of 1.75 degrees < theta < 23.02 degrees using the omega-scan technique. The structure was solved by direct methods using the program SHELXTL-93 and refined with the method of fun-matrix least-squares on F-2. The structure of the title compound may be considered to be two [Mo6O15(HPO4)(H2PO4)(3)](5-) units bonded together with a nickel atom, although several P-O groups are not protonated on account of coordination with a Na+ cation, The one-dimensional tunnels were formed in the solid of the title compound. A probe reaction of the oxidation of acetaldehyde with H2O2 using the title compound as catalyst was carried out in a liquid- solid system, showing that the title compound had high catalytic activity in the reaction, (C) 1999 Academic Press.

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Three organoselenium-containing derivatives of beta-cyclodextrins (beta-CD), mono-6-benzylseleno-6-deoxy-beta-cyclodextrin (compound 1), 6,6'-trimethylenediseleno bridged beta-cyclodextrin dimer(compound 2) and 6,6'- (o-phenylene)diseleno bridged beta-cyclodextrin dimer (compound 3) functioned as mimics of selenium-containing glutathione peroxidase(SeGPX). Acting on H2O2 and GSH, the SeGPX activities of these compounds were 0.83-, 0.26-, and 1. 23-fold of that of Ebselen (0.99 U/mu mol), respectively. The relationship between the structure and the function of these compounds was studied. The results suggested that the hydrophobicity and rigidity of phenyl group is the main reason that accounted for the higher activity of compounds 3 and 1. Phenyl group not only provided the hydrophobic circumstance which is necessary for the catalytic function of selenium, but also make it possible that the cyclodextrin unit of compounds 1 and 3 combines the substrate with a more effective direction. Fluorometric techniques were utilized to determine the yields of the hydroxyl radical produced by Fenton reactions through the formation of hydroxy benzoic acids from benzoate. Compared with Ebselen which showed a significant inhibition effect on the formation of HO., these organoselenium-containing cyclodextrins showed a little scavenging effect on the formation of HO. throughout the whole process.

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A new ferric molybdenum phosphate containing a tunnel structure and crystallographically different clusters has been hydrothermally synthesized and structurally characterized by single crystal X-ray diffraction. A probe reaction of the oxidation of acetaldehyde with H2O2 using the tide compound as catalyst was carried out in a liquid-solid system, showing that the title compound had high catalytic activity in the reaction. (C) 1998 Elsevier Science S.A. All rights reserved.

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A new complex K5H[Co-4(VW9O33)(2)]. 5H(2)O was prepared and its structure was determined by X - ray diffraction analysis. The anion has alpha - beta - Keggin structure. Two (VW9O33)(7-) moieties (alpha - B isomers) are linked via four Co(11)O-6 groups. The single crystal of the title complex is monoclinic P2(1/n) with a = 1.2307(3) nm, b = 2.1250(4) nm, c = 1.5817(3) nm, beta = 91.86(3)degrees, V = 4.1343 (14) nm(3), R = 0.0895, R-w = 0.2180.

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Organic-inorganic radical salt (DBTTF)(6)PMo12O40 . 2H(2)O was synthesized by electrocrystallization and characterized by IR spectrum, electronic spectrum and ESR technology, Its magnetic property, conductivity and crystal structure were determined. The title compound crystallized in a triclinic system with P1 space group, a = 1.378 7(7), b = 1.420 4 (2), c = 1.570 2(2) nm, alpha = 104.57(1)degrees, beta = 103.41(2)degrees, gamma = 95.80(2)degrees, V = 2.853(2) nm(3) Z = 1 and a final R = 0.072 7.