密堆积六方结构Ni纳米颗粒的制备与表征

采用溶胶-凝胶方法制备前驱体, 将前驱体进行热处理制得密堆积六方结构(hcp)的Ni纳米粉末. 利用TG-DTA, XRD和TEM等测试手段对材料的合成条件、结构、形貌以及结构演变过程进行了分析. 结果表明, 于300 ℃进行热处理所合成的样品为球形的具有密堆六方结构的Ni纳米颗粒, 晶胞参数a=0.2652 nm, c=0.4334 nm, 平均晶粒尺寸约为12 nm. 随着热处理温度的升高, 样品结构发生由密堆六方结构向面心立方结构的转变.     

Simultaneously inducing synthesis of semiconductor selenium multi-armed nanorods and nanobars through bio-membrane bi-templates

Teeth, bones, and shells are known as the prod-ucts of biological mineralization by cells[1—4]. They arenano-dimensional materials synthesized by organismitself. Bio-membrane, formed by the orderly arrange-ment of cells, is highly regular and controllable. Somedifficult functions such as high penetrability and se-lectivity that haven not been achieved can be obtainedby bio-membrane with powerful transmission capacityand ideal separation efficiency. Recently, monomo-lecular membrane[5] and mul…     

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, crystal structure, and thermal properties of N,N′-di(diethoxythiophosphoryl)-1,4-phenylenediamine

The title compound N,N′-di(diethoxythiophosphoryl)-1,4-phenyl-enediamine was synthesized by the reaction of diethoxythiophosphoryl chloride with p-phenylenediamine and characterized by elemental analysis, IR, and ¹H NMR spectra. Its crystal structure was determined by X-ray diffraction analysis and the thermal property was studied by TG analysis. The relative molecular weight of the title compound is 412.42. The crystal structure belongs to the orthorhombic, Pbca space group, with a = 0.86936(16) nm, b = 1.2787(2) nm, c = 1.8897(3) nm, β = 90°, V = 2.1006(7) nm³, Z = 8, Dc = 1.304 g/cm³, μ(Mo Kα) = 0.425 mm⁻¹, F(000) = 872, S = 1.052, the final R = 0.0628 and wR = 0.1860 for 1852 observed reflections with I>2σ(I). The X-ray diffraction analysis demonstrates that the crystal structure is centrosymmetric. The weak N-H⋯S intramolecular hydrogen bonds were observed to link the molecules into sheets. The TG analysis shows that the title compound has good thermal stability and char forming capability and its fire retardation for polyacrylonitrile reveals that the compound is an excellent intumescent fire retardant. __________ Translated from Acta Chimica Sinica, 2007, 65(18): 2034–2038 [译自: 化学学报]     

Preparation of zirconium diboride ultrafine hollow spheres by a combined sol–gel and boro/carbothermal reduction technique

In this work, we introduce a modified novel silica sol–gel process to synthesize hexagonal close-packed (hcp) and face-centered cubic (fcc) nickel (Ni) nanoparticles supported on amorphous carbon and silica matrix. The supporting of amorphous carbon and silica can prevent the Ni nanoparticles from aggregating and being oxided which would result in the loss of their magnetism and dispersibility. The phase structure of the Ni nanoparticles which were obtained from the gels pyrolyzed from 250 to 350 °C is hcp structure, whereas that of the Ni nanoparticles pyrolyzed at 750 °C is fcc structure. The grain sizes of the hcp Ni nanoparticles calcined at 250 °C range from 5 to 20 nm in diameter, and that of the fcc Ni nanoparticles calcined at 750 °C range in 7–35 nm. The studies of magnetic properties of the hcp and fcc Ni nanoparticles show that both have quite different magnetic behaviors.     

Comparison of the magnetic properties of metastable hexagonal close-packed Ni nanoparticles with those of the stable face-centered cubic Ni nanoparticles

We report the first magnetic study of pure and metastable hexagonal close-packed (hcp) Ni nanoparticles (sample 1). We also produced stable face-centered cubic (fcc) Ni nanoparticles, as mixtures with the hcp Ni nanoparticles (samples 2 and 3). We compared the magnetic properties of the hcp Ni nanoparticles with those of the fcc Ni nanoparticles by observing the evolution of magnetic properties from those of the hcp Ni nanoparticles to those of the fcc Ni nanoparticles as the number of fcc Ni nanoparticles increased from sample 1 to sample 3. The blocking temperature (T(B)) of the hcp Ni nanoparticles is approximately 12 K for particle diameters ranging between 8.5 and 18 nm, whereas those of the fcc Ni nanoparticles are 250 and 270 K for average particle diameters of 18 and 26 nm, respectively. The hcp Ni nanoparticles seem to be antiferromagnetic for T < T(B) and paramagnetic for T > T(B). This is very different from the fcc Ni nanoparticles, which are ferromagnetic for T < T(B) and superparamagnetic for T > T(B). This unusual magnetic state of the metastable hcp Ni nanoparticles is likely related to their increased bond distance (2.665 angstroms), compared to that (2.499 angstroms) of the stable fcc Ni nanoparticles.     

Preparation of nanometer MgO by sol-gel auto-combustion

Nanometer MgO was prepared via a sol-gel auto-combustion technique using magnesium nitrate as raw material and citric acid as chelating agent. IR spectra of the dried gel were used to investigate the structure of the precursors. By studying the different TG curves of magnesium citrate gel prepared by different methods, we found that a combustion process occurred and the nitrate ions acted as an oxidant in the combustion process. TEM photographs of synthesized powders from the sol-gel auto-combustion showed that the crystallites were uniform in size. In addition, the XRD pattern of this sample showed that the particle size was 8.9 nm. The BET curves, in turn, showed that the specific surface of the sample was 26.34 m²/g. The mechanism of the frothing process in restraining agglomeration is discussed. __________ Translated from Journal of East China Normal University (Natural Science), 2007, (2): 52–57 [译自: 华东师范大学学报(自然科学版)]     

Calix[4]arene based selective fluorescent chemosensor for organic acid recognition

A novel calix[4]arene-based fluorescent chemosensor bearing a 2-aminopyridine moiety and a naphthalenic fluorophore was synthesized The chemical structure of the product was elucidated by FT-IR, MS-FAB, NMR and elemental analyses. Then, the properties and identification mechanism of the synthesized chemosensor were investigated. The results show that the chemosensor exhibits selective fluorescent quenching in the presence of aromatic organic acid in acetonitrile solution, and that the binding ability of the chemosensor with organic acid is in the order of p-cyanic-benzyl acid > p-chloric-benzyl acid > p-methoxyl-benzyl acid > benzyl acid. __________ Translated from Journal of South China University of Technology (Natural Science Edition), 2007, 35(4): 20–24 [译自: 华南理工大学学报(自然科学版)]     

多孔碳负载镍纳米颗粒的制备及催化氨硼烷水解制氢

合成了蜂窝状的分级多孔碳,并以多孔碳为载体通过浸渍-化学还原法制备碳载镍(Ni/C)作为催化氨硼烷水解制氢的催化剂。采用XRD、BET、SEM、Raman、TEM等手段对样品进行了表征并研究了Ni/C室温催化性能。结果显示,多孔碳比表面积高达737 m2·g-1,具有部分石墨化结构;负载的非晶态镍纳米颗粒平均粒径约为10 nm,均匀分布在碳基材。碳载镍对氨硼烷水解反应具有良好的催化活性,镍负载量为30wt%时催化性能最佳,298 K温度下放氢速率达到1 304.67 m L·min-1·g-1,活化能为29.1 k J·mol-1,并且具备一定的催化稳定性,表明Ni/C可作为一种廉价高效的催化剂应用于催化氨硼烷水解制氢。     

多孔碳负载镍纳米颗粒的制备及催化氨硼烷水解制氢

合成了蜂窝状的分级多孔碳,并以多孔碳为载体通过浸渍-化学还原法制备碳载镍(Ni/C)作为催化氨硼烷水解制氢的催化剂。采用XRD、BET、SEM、Raman、TEM等手段对样品进行了表征并研究了Ni/C室温催化性能。结果显示,多孔碳比表面积高达737 m²·g^-1,具有部分石墨化结构;负载的非晶态镍纳米颗粒平均粒径约为10 nm,均匀分布在碳基材。碳载镍对氨硼烷水解反应具有良好的催化活性,镍负载量为30wt%时催化性能最佳,298 K温度下放氢速率达到1 304.67 mL·min^-1·g^-1,活化能为29.1 kJ·mol^-1,并且具备一定的催化稳定性,表明Ni/C可作为一种廉价高效的催化剂应用于催化氨硼烷水解制氢。     

Preparation of mesoporous aluminophosphate using poly(amido amine) as template

Mesoporous aluminophosphate was prepared by using G4.0 poly(amido amine)dendrimer as a template and characterized by Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), transmission electron microscopy (TEM) and N₂ adsorption/desorption methods. Results show that the title compound exhibits a typical mesoporous structure with the average pore size from 5 to 8 nm. The formation mechanism of the nanoporous structure using dendrimer as a template was also discussed. __________ Translated from Journal of Fujian Normal University (Natural Science Edition), 2007, 23(2): 67–70 [译自: 福建师范大学学报 (自然科学版)]     

Synthesis and crystal structure of inclusion compounds: Trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid with boric acid and tetrabutylammonium salt

Two new inclusion compounds (n-C₄H₉)₄N⁺C₁₈-H₁₃O₄ ⁻·B(OH)₃ (1) and (n-C₄H₉)₄N⁺C₁₈H₁₃O₄ ⁻ (2) were prepared and characterized by X-ray crystallography. Crystal data: compound 1, monoclinic P2(1)/c, a = 1.569 9(1) nm, b = 0.995 5(6) nm, c = 2.293 3(1) nm, β = 109.962(3)°, Z = 4, and R ₁ = 0.0434, wR = 0.075 9; compound 2, monoclinic C2/c, a = 1.400 5(3) nm, b = 1,282 1(2) nm, c = 1.765 7(3) nm, β = 100.388(1)°, Z = 4, and R ₁ = 0.0584, wR = 0.096 6. In the crystal structure of 1, the tetramers formed by two trans-9,10-dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (EADA) anions and two boric acid molecules were connected through O—H⋯O hydrogen bonds to generate a channel type host lattice. The tetra-n-butylammonium cations were stacked to give two columns within each channel with cross-sectional size of about 2.30 nm × 0.93 nm. In the crystal structure of 2, similar honeycomb host lattices with big size were also formed along the [101] direction by three-dimensional accumulation of EADA anions. The tetra-n-butylammonium cations were accommodated in a zigzag fashion within each channel. Translated from Acta Chimica Sinica, 2006, 64(18): 1904–1910 [译自: 化学学报]     

Structural,optical and photoluminescence properties of Zn<Subscript>1−x</Subscript>Ce<Subscript>x</Subscript>O (x = 0, 0.05 and 0.1) nanoparticles by sol–gel method annealed under Ar atmosphere

Ce doped ZnO nanoparticles (Zn_1−xCe_xO, x = 0.0, 0.05 and 0.1) have been synthesized by sol–gel method at annealing temperature of 500 °C for 1 h under Ar atmosphere. The synthesized samples have been characterized by powder X-ray diffraction (XRD), energy dispersive X-ray studies, UV–Visible spectrophotometer and fourier transform infrared (FTIR) spectroscopy. The XRD measurements indicate that the prepared nanoparticles have a hexagonal wurtzite structure and CeO₂ crystallites. The calculated average crystalline varied from 21.97 to 15.62 nm with increase in Ce concentrations. The increase in lattice parameters reveals the substitution of Ce into ZnO lattice. The presence of functional groups and the chemical bonding is confirmed by FTIR spectra. PL spectra of the Zn_1−xCe_xO system show that the shift in near band edge emission from 386 to 363 nm and a shift in blue band emission from 517 to 485 nm which confirms the substitution of Ce into the ZnO lattice.     

Photocatalytic degradation of methylene blue on Fe3+-doped TiO2 nanoparticles under visible light irradiation

Fe³⁺-doped TiO₂ composite nanoparticles with different doping amounts were successfully synthesized using sol-gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM) and ultravioletvisible spectroscopy (UV-Vis) diffuse reflectance spectra (DRS). The photocatalytic degradation of methylene blue was used as a model reaction to evaluate the photocatalytic activity of Fe³⁺/TiO₂ nanoparticles under visible light irradiation. The influence of doping amount of Fe³⁺ (ω: 0.00%–3.00%) on photocatalytic activities of TiO₂ was investigated. Results show that the size of Fe³⁺/TiO₂ particles decreases with the increase of the amount of Fe³⁺ and their absorption spectra are broaden and absorption intensities are also increased. Doping Fe³⁺ can control the conversion of TiO₂ from anatase to rutile. The doping amount of Fe³⁺ remarkably affects the activity of the catalyst, and the optimum efficiency occurs at about the doping amount of 0.3%. The appropriate doping of Fe³⁺ can markedly increase the catalytic activity of TiO₂ under visible light irradiation. __________ Translated from Journal of Northwest Normal University (Natural Science), 2006, 42(6): 55–56 [译自: 西北师范大学学报(自然科学版)]     

Hydrothermal preparation of nanostructured MnO2 and morphological and crystalline evolution

Manganese dioxides with various morphologies were prepared using a common hydrothermalmethod without any templates or additives. The evolution of the morphology was accompanied by the gradual conversion of the polymorphic forms from γ-type to β-type. Meanwhile, MnO₂ microspheres, urchin-like nanostructures and nanowires were successfully synthesized. The products were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscope and transmission electron microscope. The evolution process can be explained by the Ostwald Ripening mechanism. __________ Translated from Chinese Journal of Chinese Universities 28(7): 1223–1226 [译自: 高等学校化学学报]     

Polymerization of styrene catalyzed by rare earth Schiff base complexes

The rare earth Schiff base complex Nd (H₂Salen)₂Cl₃·2C₂H₅OH was synthesized by a simple and convenient method and characterized by IR and elemental analysis. The catalyst system composed of Nd (H₂Salen)₂Cl₃·2C₂H₅OH/Al(i-Bu)₃/CCl₄ is effective for the polymerization of styrene (St). The optimum conditions are as follows: [St]/[Nd] = 1000, [CCl₄]/[Nd] = 9, [Al]/[Nd] = 30, and polymerization at 50°C for 20 h. The resulting polystyrene was characterized by NMR and GPC. The results of NMR show that the polymer obtained had a stereoregularity with 52.3% isotacticity and 47.7% syndiotacticity without any random structure. __________ Translated from Journal of Zhejiang University (Science Edition), 2007, 34(2): 189–196 [译自: 浙江大学学报(理学版)]     

Shape-memory and biocompatibility properties of segmented polyurethanes based on poly(L-lactide)

A series of segmented poly(L-lactide)-polyurethanes (PLA-PUs) were synthesized by a two-step method, with oligo-poly(L-lactide) (PLA) as the soft segments and the reaction product of 2,4-toluene diisocyanate (TDI) and ethylene glycol (EG) as the hard segments. The shape-memory properties and biocompatibility of PLA-PUs were examined. The 50% compressed PLA-PUs could recover almost 100% to their original shape within 10°C from the lowest recovery temperature (22°C–37°C). In the recovery process the PLA-PU showed a maximum contracting stress in the range of 1.5–4 MPa. Cell incubation experiments show that PLA-PU has biocompatibility comparable to that of pure PLA. Therefore, this kind of polyurethane can be used for implanted medical devices with shape memory requirements. __________ Translated from Chemical Journal of Chinese Universities, 2007, 28(2): 371–375 [译自: 高等学校化学学报]     

Synthesis of Ni nanoparticles and their characterizations

Ni nanoparticles were synthesized by solution reduction process successfully. The influence of parameters on the size of Ni nanoparticles was studied and the referential process parameters were obtained. The morphology and structure of the synthesized Ni nanoparticles were characterized by transmission electron microscopy (TEM), powder X-ray diffraction (XRD), QELS data and infrared spectroscopy (IR). The result shows that Ni nanoparticles are of high purity and the average size of Ni nanoparticles was found to be 13 ± 2 nm.     

Preparation and properties of luminous materials of CaSiO3: Pb, Mn by sol-gel method

The luminous materials of CaSiO₃: Pb, Mn were synthesized by sol-gel method and ultrasound technology. The properties of the phosphors were characterized by luminescence spectrum, differential thermal analysis and thermal gravimetry analysis (DTA-TG), X-ray diffraction (XRD), Fourier transform infrared spectrometer (FT-IR) and transmission electron microscopy (TEM). The effects of factors such as the synthetic material compositions, ultrasound time and annealed temperature on phosphorescent brightness of sample were studied and the optimum synthetic conditions were determined. The results show that, compared with the sample made by the high temperature solid-state reaction, the luminescent intensity of the CaSiO₃: Pb, Mn sample increased by about 200% and the mean diameter of particles of the sample decreased by about 300 nm. __________ Translated from Chemical Research and Application, 2007, 19(2): 140–144 [译自: 化学研究与应用]     

Synthesis of AB2 star-shaped miktoarm copolymers and their crystallization behavior

A small molecule (GMS-SA₂) with one alkyl chain and two terminal carboxyl groups was synthesized successfully by the reaction of glyceryl monostearate (GMS) with excess succinic anhydride (SA). Then, GMS-SA₂ was used as a coupling agent to condensate with polyethylene glycols (PEG) of different molecular weight or polyethylene glycol monomethyl ether (PEGm) in the presence of stannous octoate as catalyst and diphenyl ether as azeotropic agent. The AB₂ star-shaped miktoarm copolymers were obtained successfully and were characterized by ¹H-NMR, DSC, GPC, XRD, FTIR and polarizing microscopy. The results of DSC and XRD measurements indicate that the crystallization temperature and the melting temperature of the AB₂ star-shaped miktoarm copolymers are different from those of the corresponding linear PEGs, because the existing of GMS-SA₂ alters their crystalline growth velocity and the perfect degree of crystals. It is very important to control the crystal morphology of star-shaped copolymers by introducing the miktoarm into the starshaped polymers and adjusting its content in star-shaped polymers. __________ Translated from Chemical Journal of Chinese Universities, 2007, 28(7): 1365–1370 [译自: 高等学校化学学报]