Self-assembled 3D flowerlike Lu2O3 and Lu2O3 : Ln(3+) (Ln = Eu, Tb, Dy, Pr, Sm, Er, Ho, Tm) microarchitectures: Ethylene glycol-mediated hydrothermal synthesis and luminescent properties

Three-dimensional flowerlike Lu2O3 and Lu2O3:Ln(3+) (Ln = Eu, Th, Dy, Pr, Sm, Er, Ho, Tm) microarchitectures have been successfully synthesized via ethylene glycol (EG)-mediated hydrothermal method followed by a subsequent heat treatment process. X-ray diffraction, Fourier transform infrared spectroscopy, energy-dispersive X-ray spectra, thermogravimetric and differential thermal analysis, elemental analysis, inductively coupled plasma atomic absorption spectrometric analysis, ion chromatogram analysis, X-ray photoelectron spectra, scanning electron microscopy, transmission electron microscopy, photoluminescence spectra as well kinetic decays, and cathodoluminescence spectra were used to characterize the samples. Hydrothermal temperature, EG, and CH3COONa play critical roles in the formation of the lutetium oxide precursor microflowers. The reaction mechanism and the self-assembly evolution process have been proposed. The as-formed lutetium oxide precursor could transform to Lu2O3 With their original flowerlike morphology and slight shrinkage in the size after postannealing process.

Hydrothermal synthesis, crystal structure and electrochemical properties of a novel 3D Dawson-type polyoxometalate supramolecular network

A novel Dawson-type polyoxometalate supramolecular architecture of the formula [4,4'-H(2)bipy](2.5)center dot[4,4'-Hbipy]center dot[P2W18O62]center dot 6.25H(2)O (4,4'-bipy = 4,4'-bipyridine) has been hydrothermally synthesised and characterised by means of elemental analysis, IR, CV and X-ray single-crystal diffraction. X-ray crystallography indicates that the title compound consists of Dawson-type polyoxoaions [P2W18O62](6-), water molecules and 4,4'-bipy units. The polyoxoanion clusters together with 4,4'-bipy units and water molecules to construct the three-dimensional supramolecular network through hydrogen bonds. The crystal structure analyses reveal that water molecules and 4,4'-bipy units play the important role on the packing arrangements of crystals. Cyclic voltammetry shows that the title compound exhibits three chemically reversible steps

3D 异金属Bi(III)-Pr(III)配位聚合物的合成、晶体结构和热稳定性

在水溶液中合成了双金属配位聚合物({[(NO3)(H2O)3Pr(μ4-Hedta)Bi-(NO3)2].2H2O}2)n,并通过元素分析、红外光谱和X射线单晶衍射等手段进行了表征.该配合物为单斜晶系,P2(1)/n空间群,a=1.26831(18)nm,b=0.82189(12)nm,c=2.3755(3)nm,β=105.055(2)°,R=0.0429,V=2.3913(6)nm3,Z=4.Bi(Ⅲ)-Pr(Ⅲ)间通过配阴离子Hedta3-中4个羧基的桥联作用构建配合物的3D结构.TG-DSC结果表明,该配合物热分解经历脱水、配体分解以及盐分解过程,残余物为Bi-Pr-O的三元复合氧化物.

Synergetic Effect of Efficient Energy Transfer and 3D pi-pi Stack for White Emission Based on the Block Copolymers Containing Nonconjugated Spacer

A series of block copolymers containing nonconjugated spacer and 3D pi-pi stacking structure with simultaneous blue-, green-, and yellow-emitting units has been synthesized and characterized. The dependence of the energy transfer and electroluminescence (EL) properties of these block copolymers on the contents of oligo(phenylenevinylene)s has been investigated. The block copolymer (GEO8-BEO-YEO4) with 98.8% blue-emitting oligomer (BEO), 0.8% green-emitting oligomer (GEO), and 0.4% yellow-emitting oligomer (YEO) showed the best electroluminescent performance, exhibiting a maximum luminance of 2309 cd/m(2) and efficiency of 0.34 cd/A. The single-layer-polymer light-emitting diodes device based on GEO2-BEO-YEO4 emitted greenish white light with the CIE coordinates of (0.26, 0.37) at 10 V. The synergetic effect of the efficient energy transfer and 3D pi-pi stack of these block copolymers on the photoiuminescent and electroluminescent properties are investigated.

Templateless, surfactantless, simple electrochemical route to rapid synthesis of diameter-controlled 3D flowerlike gold microstructure with "clean" surface

We report for the first time a simple low-cost electrochemical route to synthesis of diameter-controlled hierarchical flowerlike gold microstructures with "clean'' surfaces using gold nanoplates or nanopricks as building blocks without introducing any template or surfactant.

SBS as template to synthesize 3D siliceous mesostructured cellular foams

A mesostructured cellular foam (MCF) with three-dimensional (313) disordered strutlike structure is prepared by using triblock copolymer (poly(styrene-b-butadiene-b-styrene), SBS, M-W = 140K) as template under strong acid conditions. It is the first report to use triblock copolymer with both hydrophobic head and tail groups instead of hydrophilic head and hydrophobic tail copolymers to synthesize siliceous mesostructured cellular foams. The resulted materials have high pore volume (0.92 cm(3)/g) and relatively narrow pore size distributions with a large pore size of 7.9 nm, which will allow for the fixation of large active complexes, reduce diffusional restriction of reactants and enable reactions involving bulky molecules to take place, especially.

Electronic structures of 3d-metal mononitrides

Bond distances, vibrational frequencies, electron affinities, ionization potentials, and dissociation energies of the title molecules in neutral, positively, and negatively charged ions were studied by use of density functional methods B3LYP, BLYP, BHLYP, BPW91, and B3PW91. The calculated results are compared with experiments and previous theoretical studies. It was found that the calculated properties are highly dependent on the functionals employed, in particular for the dissociation energy and vibrational frequency. For neutral species, pure density functional methods BLYP and BPW91 have relatively good performance in reproducing the experimental bond distance and vibrational frequency. For cations, hybrid exchange functional methods B3LYP and B3PW91 are good in predicting the dissociation energy. For both neutral and charged species, BHLYP tends to give smaller dissociation energy.

Electronic structures and chemical bonding in transition metal monosilicides MSi (M=3d, 4d, 5d elements)

Bond distances, vibrational frequencies, electron affinities, ionization potentials, dissociation energies, and dipole moments of the title molecules in neutral, positively, and negatively charged ions were studied using the density functional method. Ground state was assigned for each species. The bonding patterns were analyzed and compared with both the available data and across the series. It was found that besides an ionic component, covalent bonds are formed between the metal s, d orbitals and the silicon 3p orbital. The covalent character increases from ScSi (YSi) to NiSi (PdSi) for 3d (4d) metal monosilicides, then decreases. For 5d metal monosilicides, the covalent character increases from LaSi to OsSi, then decreases. For the dissociation of cations, the dissociation channel depends on the magnitude of the ionization potential between metal and silicon. If the ionization potential of the metal is smaller than that of silicon, channel MSi+-> M++Si is favored. Otherwise, MSi+-> M+Si+ will be favored. A similar behavior was observed for anions, in which the dissociation channel depends on the magnitude of electron affinity.

One-step synthesis of 3D dendritic gold/polypyrrole nanocomposites via a self-assembly method

Novel spherical three-dimensional (3D) dendritic gold-polypyrrole nanocomposites were successfully prepared in the presence of an amphiphilic p-toluene sulfonic acid (TSA) as dopant and surfactant via a self-assembly process which is based on the oxidation of pyrrole (Py) and the reduction of the chloroaurate ions, yielding PPy and Au(0) simultaneously. It was found that the probability of obtaining dendritic Au@PPy/TSA nanostructures depended on the concentration of TSA and the rate of addition of the oxidant (HAuCl4), It was also proposed that the supramolecular micelles formed by Py and TSA play the role of a 'soft template' to produce the dendritic Au@PPy/TSA nanocomposites.

Effects of SBS addition and temperature on 3D siliceous mesostructured cellular foam

Siliceous mesostructured cellular foam with three-dimensional (3D) wormhole structure (MSU-type) is prepared by using triblock copolymer (poly(styrene-b-butadiene-b- styrene), SBS) with both hydrophobic head and tail group as template in strong acid condition via microemulsion method. The effects of SBS addition and temperature on the morphology and physicochemical properties, such as pore diameters, surface areas and pore volumes of the materials have been investigated by powder X-ray diffraction (XRD), transmission electron microscopy (TEM), field emission scanning electron microscope (FE-SEM) and nitrogen adsorption-desorption analysis. The results show that the pore volumes, pore sizes and specific surface areas depend strongly on the SBS amount and forming micelles temperature. Moreover, the materials obtained with high wall thickness exhibit a relatively good thermal stability.

Synthesis, crystal structure, and magnetic properties of {[Cu(oxbe)]Mn(H2O)[Cu(oxbe)(DMF)]}(n)center dot nDMF center dot nH(2)O: From dissymmetrical mononuclear entities to a 3D heterometallic supramolecular coordination polymer

Self-assembly of the building block [Cu(oxbe)](-) with Mn(II) led to a novel coordination polymer {[Cu(oxbe)]Mn(H2O)(Cu(oxbe)(DMF)]}(n).nDMF.nH(2)O, where H(3)oxbe is a new dissymmetrical ligand N-benzoato-N'-(2-aminoethyl)-oxamido and DMF = dimethylformamide. The crystal forms in the triclinic system, space group P(1)over-bar, with a = 9.260(4) angstorm, b = 12.833(5) angstrom, c = 15.274(6) angstrom , alpha = 76.18(3)degrees, beta = 82.7(3)degrees, gamma = 82.31(3)degrees, and Z = 2. The crystal structure of the title complex reveals that the two-dimensional bimetallic layers are constructed of (CuMnII)-Mn-II-Cu-II chains linked together by carboxylate bridge and hydrogen bonds help to produce a novel three-dimensional channel-like structure. The magnetic susceptibility measurements (5-300 K) were analyzed by means of the Hamiltonian (H)over-cap = -2J(S)over-cap (Mn)((S)over-cap(Cu1) + (S)over-cap(Cu2)), leading to J = -17.4 cm(-1).

A novel 3D network coordination polymer consisting of paddlewheel Co-3 clusters connected by PO4 and 4-pyridinecarboxylate

The synthesis, structural characterization and preliminary magnetic studies of a novel coordination polymer with paddlewheel Co-3 clusters are reported firstly. In the polymer, Co-3 clusters are covalently linked through PO4 tetrahedra and 4-pyridinecarboxylate (4-pya) ligands into interpenetrated three-dimensional network.

Investigation of covalency and spectrum shifts in 3d transition-metal compounds

By using a correction factor of d electron effects on bond, PV theory is applied to the calculation of chemical bond;parameters of d transition-metal compounds. Racah parameters and Mossbauer isomer shifts are calculated, and the results are agreement with the experimental values.

类吗啡类拮抗物的结构与抑食活性的3D-QSAR研究

用比较力场分析研究了 3 ,4 二甲基 4 ( 3 羟基苯基 )哌啶及其衍生物类吗啡拮抗物的结构与抑食活性的关系 ,考察了网格结构和探针原子的影响 .结果表明 ,立体效应和静电作用场是描述其抑食活性和进行结构性能关系研究的最重要的结构参数