Synthesis, Characterization and Conductivity of α-Keggin-type Nanoparticles, Co(en)_3PMo_(12)O_(40)·8H_2O with Optical Activity

IntroductionChirality is ubiquitous in the nature.Chiralcompounds have many applications in the areas ofmedicine,catalysis and materials,etc. Polyox-ometallates are inorganic polymers,which have at-tracted much interest since they have electri-cal[1_ 3 ] ,magnetic[4] ,optical properties[5_ 7] ,andsome characters as liquid crystals[8,9] .In this workwe report theα- Keggin structural polyoxometallatenanoparticles with optical activities.The opticalactivities of the samples are [α]13 D =+ 1 7…     

Synthesis and Structure of a NovelTetranuclear Erbium( Ⅲ) Complex with α-Alanine [Er4(Hala)6·(μ3-OH)4(H2O)8](ClO4)8·3H2O

The title complex was synthesized in an aqueous solution and its crystal structure was determined by X-ray diffraction. The crystal crystallizes in a triclinic system, space group P1 with a=1.306 3(2) nm, b=1.319 4(4) nm, c=1.950 2(4) nm, α=90.597(14)°, β=93.998(11)°, γ=94.093(13)°, V=3.344 1(12) nm3, Z=2, the final R indices are R1=0.065 4, wR2=0.126 2 respectively. The complex contains a novel tetranuclear cluster cation with four Er3+ ions connected by four μ3-OH ions and six bridging carboxyl groups. Each erbium ion is coordinated by three μ3-OH, three carboxylic oxygen atoms from three α-alanine and two oxygen atoms from water molecules, forming a square-antiprismatic coordination polyhedron.     

Crystal structure and properties of H3[PMo12O40] · 3C2H6O

The title compound H₃[PMo₁₂O₄₀]· 3C₂H₆O was prepared and characterized by X-ray crystallography, its i.r. spectrum, cyclic voltammetry and e.s.r. spectra. The anion of the title compound is a Keggin-type heteropoly structure based upon a central PO₄ tetrahedron surrounded by 12 MoO₆ octahedra arranged in four groups of three edge-shared octahedra Mo₃O₁₃. Weak hydrogen bonds exist between the organic solvent molecules and the heteropoly anion. The catalytic activity of the title compound was determined by the synthesis of butyl acetate. The conversion of n-BuOH reached 93.3% and the yield of MeCO₂Bu-n was 92.0% when the ratio of MeCO₂H to n-BuOH, catalyst amount, reaction time, reaction temperature were 2:1, 0.24% of the reactants (50 mg), 2.0 h and 115 120 °C, respectively.     

Synthesis,crystal structure,and catalytic performance of two 3-D supramolecular compounds: (C7N2H7)3(C7N2H6) · PMo12O40 · 2H2O and (C7N2H7)3(C7N2H6)2 · AsMo12O40 · 3H2O

Two organic–inorganic compounds based on Keggin building blocks have been synthesized by hydrothermal methods, (C₇N₂H₇)₃(C₇N₂H₆)?·?PMo₁₂O_40?·?2H₂O (1) and (C₇N₂H₇)₃(C₇N₂H₆)_2?·?AsMo₁₂O_40?·?3H₂O (2) (C₇N₂H₆?=?benzimidazole). Single-crystal X-ray analysis revealed that 1 crystallized in the triclinic system, P-1 space group with a?=?9.8980(4)?Å, b?=?11.2893(4)?Å, c?=?25.8933(9)?Å, α?=?93.307(2)°, β?=?90.630(2)°, γ?=?108.330(2)°, V?=?2740.68(18)?ų, Z?=?2, R ₁(F)?=?0.0740, ωR ₂(F ²)?=?0.1511, and S?=?1.037; 2 crystallized in the triclinic system, P-1 space group with a?=?12.3353(4)?Å, b?=?13.2649(4)?Å, c?=?20.2878(6)?Å, α?=?95.6630(10)°, β?=?100.1720(10)°, γ?=?99.3940(10)°, V?=?3195.72(17)?ų, Z?=?2, R ₁(F)?= 0.0329, ωR₂ (F ²)?=?0.1236, and S?=?1.088. The two compounds show a layer framework constructed from Keggin-polyoxoanion clusters and benzimidazole via hydrogen bonds and π–π stacking interactions, resulting in a 3-D supramolecular network. Both have high catalytic activity for oxidation of methanol. When the initial concentration of the methanol is 5.37?g?m^?3 in air and the flow velocity is 4.51?mL?min^?1, methanol is completely eliminated at 150°C for 1 (160°C for 2).     

Synthesis, Crystal Structure and Luminescent Property of [Zn(C12H9O3)2(C10H8N2)]n·nH2O

Under hydrothermal condition, the reaction of 2-naphthoxyacetic acid with ZnCl2 and 4,4'-bipyridine (4,4'-bipy)has afforded a new Zn(Ⅱ) compound,[Zn(C12H9O3)2(C10H8N2)]n·nH2O1, which was structurally characterized by single-crystal X-ray diffraction analysis. The crystal is of monoclinic, space group P21/c with a = 7.7335(2), b = 19.3834(4), c = 20.1707(4) (A), β =104.9830(10)°, V = 2920.82(11) A3, C34H28ZnN2O7, Mr = 641.95, Z = 4, Dc = 1.460 g/cm3, μ = 0.895 mm-1, F(000) = 1328, R = 0.0406 and wR = 0.0876 for 4417 observed reflections (Ⅰ>2σ(Ⅰ)). Complex 1 consists of one-dimensional zigzag chains deriving from Zn(C12H9O3)2 units linked by 4,4'-bipy ligands, and lattice water molecules decorate between the chains. Non-covalent interactions, such as hydrogen-bonding and aromatic π-π interactions, lead to the formation of a 3D network structure. The thermogravimetric analysis (TGA) and luminescent property for 1 have also been studied in this paper.     

Synthesis,Characterization and Antimicrobial Properties of Superparamagnetic α-Fe2O3 Nanoparticles Stabilized by Biocompatible Starch

Journal of Cluster Science - In the present study we have synthesized α-Fe2O3 nanoparticles in a more conventionally established NaBH4 reduction, but using a bio-macromolecule, starch. The...     

C-V Characterization of α-Fe2O3/Block-Copolymer Composite Particulate Films

α-Fe2O3 nanocrystal was encapsulated by a block-copolymer, hydroxylated poly(styrene-b-butadiene-styrene)(HO-SBS) to fabricate composite microspheres with α-Fe2O3 cores and HO-SBS shell. Its film fabricated on n-Si wafer acts as the insulator layer in the metal-insulator-semiconductor(MIS) structure. The capacitance-voltage(C-V) properties were measured to characterize the composite particulate films.     

Synthesis,characterization and 1H NMR studies of [Co(en)2(malH)2]ClO4·H2O

The trans-[Co(en)₂(malH)₂]ClO₄·H₂O complex was prepared by the reaction of sodium hydrogen malonate with [Co(en)₂(H₂O₂](ClO₄)₃ in the presence of a large concentration of perchlorate ion. It showed a three-band visible spectrum (γγ_max 357, 448 and 542.6 nm), diagnostic of a trans-MA₄B₂ system and gave characteristic IR bands as expected for a trans-bisethylenediamine cobalt(III) complex. The ¹H NMR spectrum in DMSO-d₆ revealed a broad band at 5.8 ppm assignable to the amino hydrogen and a single band at 2.68 for the ethylene group of the chelate ring. The

group of the hydrogen malonate ion appeared as a sharp singlet at 2.95 ppm and integration showed the presence of two bimalonate groups. The reactive methylene protons were found to be exchangeable. Ion association by counter ions of the complex ion in DMSO-d₆ showed no preference among amino protons. This is as expected for trans complexes with D_2h-symmetry.     

Synthesis,Structure and Characterization of Three Metal Molybdate Hydrates: Fe(H2O)2(MoO4)2·H3O,NaCo2(MoO4)2(H3O2)and Mn2(MoO4)3·2H3O

Three metal molybdate hydrates,Fe(H2O)2(MoO4)2·H3O(FeMo),NaCo2(MoO4)2(H3O2)(CoMo)and Mn2(MoO4)3·2H3O(MnMo),were synthesized by the mixed-solvent-thermal methods and characterized by singlecrystal X-ray...     

Synthesis, crystal structure and magnetic properties of bimetallic complex of Ni2Co(TTHA)·12H2O

The bimetallic complex of Ni₂Co(TTHA)·12H₂O (TTHA = triethylene tetraminehexaacetic acid) was synthesized and characterized structurally and magnetically. The title complex crystallizes in the triclinic space group P ī with a = 0.7316(2), b = 0.8624(2), c = 1.5041(4) nm; α = 73.38(2), β = 83.97(2), γ = 70.50(2)°. The crystal structure is built up of [Ni₂(TTHA)(H₂O)₂]²⁻, Co(H₂O)₆²⁺ and water molecules. The variable magnetic measurement shows that there is strong antiferromagnetic interaction between two Ni(II) ions in [Ni₂(TTHA) (H₂O)₂]²⁻ with J _Ni−Ni = −141.64 cm⁻¹, g _Ni = 2.21 and that the constant of spin-orbit coupling of Co(II) ion is −134.8 cm⁻¹. __________ Translated from Acta Scientiarum Naturalium Universitatis Nankaiensis, 2007, 40(1): 6–10 [译自: 南开大学学报(自然科学版)]     

Synthesis and Crystal Structure of [Zn(FcCOO)2(2,2′-bipy)(H2O)]2·H2O

A novel complex [Zn(FcCOO)2(2,2′-bipy)(H2O)]2·H2O (Fc = (η5-C5H5)Fe(η5-C5H4), 2,2′-bipy = 2,2′-bipyridine) has been synthesized and characterized by elemental analysis, IR and X-ray diffraction. It crystallizes in monoclinic system, space group P21/c with a = 6.8187(4), b = 21.7155(13), c = 19.7411(12) (A), α = 90, β = 97.7420(10), γ = 90°, C64H58Fe4Zn2N4O11, Mr = 1413.28, V = 2896.4(3) (A)3, Dc = 1.620 g/cm3, Z = 2, F(000) = 1444, μ(MoKα) = 1.857 mm-1, R = 0.0523 and wR = 0.0982 for 3219 observed reflections (I ＞ 2σ(I)). Structural analysis shows that the zinc atom is coordinated with three oxygen atoms from two ferrocenemonocarboxylates and one water molecule together with two nitrogen atoms from 2,2′-bipyridine, giving a distorted square-pyramidal coordination geometry. The complex molecules are linked to form an infinite one-dimensional chain by both intermolecular hydrogen bonds and π-π stacking interactions of the bipyridine rings.     

Synthesis, Structure and Characterization of [Cu(2,2'-bpy)2][{Cu(2,2'-bpy)2}2W12O40(H2)]·4H2O

An organic-inorganic compound [Cu(2,2'-bpy)2][{Cu(2,2'-bpy)2}2W12O4o(H2)]·4H2O (Mr = 4048.00) was prepared from the hydrothermal reaction of Na2WO4·2H2O, CuCl2·2H2O,2,2'-bipyridine (2,2'-bpy) and H2O at 160 ℃ for 4 days. The compound crystallizes in the monoclinic system, space group P21/n with a = 18.9196(8), b = 20.4212(8), c = 21.8129(9)(A), β=96.992(3)°, V= 8365.0(6) (A)3, Dc= 3.214 g/cm3, Z = 4,μ(MoKα) = 17.269 mm-1 and F(000) = 7324.Of the 119837 total reflections, 17315 were unique (Rint = 0.0489). The final R = 0.0385 and wR =0.0770 for 11142 observed reflections with I ＞ 2σ(I). Single-crystal X-ray diffraction reveals that the structure is composed of [{Cu(2,2'-bpy)2}2W12O40(H2)]2- anions, discrete [Cu(2,2'-bpy)2]2 cations and lattice water molecules, and the anion is made up of a {W12O40(H2)}6- α-Keggin core decorated with two {Cu(2,2'-bpy)2}2 groups through bridging oxygen atoms.     

Synthesis, Characterization and Crystal Structure of an Inorganic-organic Composite Metatungstate: [Co(4,4'-bipy)2(H2O)4](4,4'-H2bipy)2[H2W12O40]·5.5H2O

A novel hybrid compound [Co(4,4'-bipy)2(H2O)4](4,4'- H2bipy)2[H2W12O40]·5.5H2Ohas been synthesized from an acidified aqueous solution and characterized by elemental and thermal analyses, IR and UV spectroscopy, and single-crystal X-ray structure determination. Structure analysis indicates that the title compound is of monoclinic, space group C2/c, with a = 21.315(9), b = 15.303 (7), c = 24.139(10) (A), β = 105.170(5)o, V = 7599(6) (A)3, Mr = 3706.99, Z = 4, F(000) = 6616, Dc = 3.231, μ = 18.395 mm-1, R = 0.0652 and wR = 0.1594. X-ray crystallographic study shows that the title compound consists of one [Co(4,4'-bipy)2(H2O)4]2 cation, two diprotonated 4,4'-bipyridine molecules, 5.5 water molecules of crystallization, and one metatungstate polyoxoanion [H2W12O40]6-, which approaches an effective Td point symmetry. TG-DTA analysis indicates that the framework of the metatungstate polyoxoanion is collapsed at 587.0 ℃.     

Synthesis and Crystal Structure of [{Cd(hmbdc)(H_2O)_3}·2H_2O]_n

A novel coordination polymer [{Cd(hmbdc)(H2O)3}·2H2O]n (hmbdc = 5-hydroxy- isophthalic acid) has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P21/c, with a = 9.599(3), b = 18.699(5), c = 7.557(2) , β = 108.198(4)°, V = 1288.6(6) 3, Z = 4, Mr = 382.60, Dc = 1.972 g/cm3, F(000) = 760, μ = 1.740, the final R = 0.0555 and wR = 0.0995 for 1732 observed reflections with I > 2σ(I). The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework.     

Synthesis, Crystal Structure and Magnetic Property of Disodium Biscarbonato cobaltate(Ⅱ) Tetrahydrate, Na_2Co(CO_3)_2·4H_2O

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Synthesis, Crystal Structure and Luminescence Property of [Co(hmz)2(H2O)4]·2H2O

A new mononuclear Co(Ⅱ) complex, [Co(hmz)2(H2O)4]·2H2O, has been synthesized by the reaction of Co(CH3COO)2·4H2O with 1-(4-hydroxyphenyl)-5-mercaptotetrazole (Hhmz). It crystallizes in the monoclinic system, space group P21/n with a = 13.502(5), b = 6.718(3), c = 13.972(6) (A), β = 117.532(4)°, V = 1123.9(8) (A)3, Z = 2, M r = 553.45, F(000) = 570, Dc = 1.635 g/cm3, μ = 1.008 mm-1, the final R = 0.0272 and wR = 0.0684 for 2194 observed reflections (Ⅰ＞ 2σ(Ⅰ)). The Co(Ⅱ) is six-coordinated by two nitrogen atoms from two hmz-1 ligands and four water molecules, forming an octahedral geometry. The intermolecular hydrogen bonding and offset-panel π-π stacking interactions between the adjacent molecules extend the compound into a three- dimensional supramolecular framework. The title compound emits strong blue fluorescent light (λem(max) = 427 nm) at room temperature and is red-shifted compared with free ligand Hhmz (λem(max) = 342 nm).     

Synthesis and Structural Characterization of Co(Ⅱ) Coordination Polymer [Co(-phth)(imi_)2]_n

1 INTRODUCTION The polymeric metal complexes with extended structures are of great interest because of their useful chemical or physical properties[1]. Due to the noticeable fact that the aromatic polycarboxylate can provide versatile coordination mode and the non-coplanar structure of the carboxylate groups and the benzene rings, a lot of efforts in this field have been particularly directed to the preparation of aromatic polycarboxylate (such as phthalate, tere- phthalate and isophthal…     

Synthesis, physical–chemical, and catalytic properties of mixed compositions Ag/H3PMo12O40/SiO2

Deposited catalysts composition H₃PMo₁₂O₄₀/SiO₂ and Ag/H₃PMo₁₂O₄₀/SiO₂ have been synthesized on the basis of fumed silica, including milling technique. Physical–chemical characteristics of prepared catalysts have been studied by means of XRD, DTA-TG, FTIR, UV–Vis spectroscopy, and adsorption of nitrogen. Catalysts possess meso- or meso-macroporous structure and contain deposited Keggin heteropolycompounds. Deposition of heteropolycompounds on support with high specific surface area results in increase of selectivity to epoxide in epoxidation reactions. The use of milling during catalyst synthesis leads to further growth of selectivity of epoxides formation.