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Crystal structure and luminescence properties of the barium europium tetragermanate Ba2Eu2Ge4O13
摘要： The tetragermanate Ba2Eu2Ge4O13 was synthesized for the first time, and its structural and luminescent properties were examined. It crystallizes in a monoclinic system (space group C2/c, Z = 4) and its crystal structure incorporates a unique linear [Ge4O13]10– anion. The photoluminescence spectrum of the sample ( llllex = 280 nm) contains several intense peaks in the orange-red spectral range corresponding to the 4f–4f transitions in Eu3+ ions.
关键词： crystal structure,Ba2Eu2Ge4O13,luminescence,Eu3+ ions,tetragermanate
更新于2025-09-04 15:30:14
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A three-dimensional Zn <sup>II</sup> coordination network based on 5,5′-methylenebis(2,4,6-trimethylisophthalic acid) and 2,7-bis(1 <i>H</i> -imidazol-1-yl)fluorene: synthesis, structure and luminescence properties
摘要： In recent years, coordination polymers constructed from multidentate carboxylate ligands and N-containing ligands have attracted much attention since these ligands can adopt a rich variety of coordination modes which can lead to crystalline products with intriguing structures and interesting properties. A new coordination polymer, namely poly[[diaqua[μ-2,7-bis(1H-imidazol-1-yl)fluorene-κ2N3:N3′][μ-5,5′-methylenebis(2,4,6-trimethylisophthalato)-κ2O1:O1′]zinc(II)] hemihydrate], {[Zn(C23H22O8)(C19H14N4)(H2O)2]·0.5H2O}n, 1, was prepared by the self-assembly of Zn(NO3)2·6H2O with 5,5′-methylenebis(2,4,6-trimethylisophthalic acid) (H4BTMIPA) and 2,7-bis(1H-imidazol-1-yl)fluorene (BIF) under solvothermal conditions. The structure of 1 was determined by elemental analysis, single-crystal X-ray crystallography, powder X-ray diffraction, IR spectroscopy and thermogravimetric analysis. Each ZnII ion is six-coordinated by two O atoms from two H2BTMIPA2? ligands, by two N atoms from two BIF ligands and by two water molecules, forming a distorted octahedral ZnN2O4 coordination geometry. Adjacent ZnII ions are linked by H2BTMIPA2? ligands and BIF ligands, leading to the formation of a two-dimensional (2D) (4,4)-sql network, and intermolecular hydrogen-bonding interactions connect the 2D layer structure into the three-dimensional (3D) supramolecular structure. Each 2D layer contains two kinds of helices with the same direction, which are opposite in adjacent layers. The luminescence properties of complex 1 in the solid state have also been investigated.
关键词： crystal structure,fluorescence properties,two-dimensional coordination polymer,supramolecular,5,5′-methylenebis(2,4,6-trimethylisophthalic acid,zinc(II),2,7-bis(1H-imidazol-1-yl)fluorene,hydrogen bonding
更新于2025-09-04 15:30:14
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The self-assembly of DyF3 nanoparticles synthesized by chloride-based route
摘要： The series of DyF3 nanoparticles was synthesized for the first time by a chloride-based route, using the water-soluble dysprosium chloride hexahydrate as a precursor. The synthesized nanoparticles have sizes of 3 to 7 nm, which is the smallest reported size for DyF3 nanoparticles. The influence of precursor concentration in an aqueous solution prior to the chemical reaction on the size of nanoparticles was studied. The influence of microwave-assisted hydrothermal treatment was also studied. The analysis of transmission electron microscopy (TEM) data revealed no correlation between the size of synthesized nanoparticles and the concentration of the aqueous solution. The AC/DC magnetic susceptibility of DyF3 nanoparticles was measured. The dipolar ferromagnetic transition for this sample was not observed down to 1.8 K that can be possibly explained by onset of superparamagnetism. The self-assembly of DyF3 nanoparticles was observed for the first time by analysis of XRD and TEM data and the evidence of superlattice formation along (020) and (210) lattice planes over the size of 20–30 nm (4–5 nanoparticles) was obtained.
关键词： X-ray techniques,Self-assembly,Nanocrystalline materials,Colloidal processing,Crystal structure,Electron microscopy
更新于2025-09-04 15:30:14
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Structural basis for a naphthyl end-capped oligothiophene with embedded metallic nanoparticles for organic field-effect transistors
摘要： We report on the apparent structure of 5,500-bis(naphth-2-yl)-2,20:50,200-terthiophene (NaT3) in organic field-effect transistors (OFETs) with and without embedded silver nanoparticles. Using regular- and microbeam grazing incidence wide- and small-angle X-ray scattering, the device structure is characterized locally in the area with the embedded particles. The NaT3 thin film order is reduced and the found unit cell (a ? 25.7 A? , b ? 5.87 A? , c ? 8.03 A? , and b ? 98.9(cid:2)) differs significantly from the one reported in the bulk, but shows no significant change, when the particles corresponding to the crystal size are incorporated into the device structure. At the same time, the apparent thin film crystal sizes in OFETs are found to be similar with and without the embedded particles. In both cases, the carrier mobilities are of the order of 10(cid:3)4 cm2/(V s).
关键词： X-ray scattering,oligothiophene,organic field-effect transistors,silver nanoparticles,crystal structure
更新于2025-09-04 15:30:14