Synthesis of Isotope Enriched (CN3H6)2[57Fe(CN)5NO] starting from 57Fe

A high‐yield, mmolar‐scale synthesis of pure guanidinium nitroprusside, (CN₃H₆)₂[⁽⁵⁷⁾Fe(CN)₅NO] (GNP) from iron metal is described. The iron metal contained pieces of 95.3% ⁵⁷Fe together with normal iron so that an isotope enrichment in ⁵⁷Fe of 25% was achieved. Single‐crystals of GNP could be grown in cubic shape and dimensions of about 3 × 4 × 4 mm³. The purity of the GNP product and the intermediates K₄[⁽⁵⁷⁾Fe(CN)₆] · 3 H₂O and Na₂[⁽⁵⁷⁾Fe(CN)₅NO] · 2 H₂O was ascertained by ⁵⁷Fe Mössbauer spectroscopy as well as ¹³C, ¹⁴N and ⁵⁷Fe NMR spectroscopy. The ⁵⁷Fe NMR chemical shift for [⁽⁵⁷⁾Fe(CN)₅NO]^2– in GNP was detected at +2004.0 ppm [vs Fe(CO)₅].     

Fe3O4@Gd2O3:Eu3+磁光双功能复合粒子的制备与表征

采用水热法合成了Fe3O4@Gd2O3:Eu3+核壳结构磁光双功能复合粒子,对其结构和性能进行了表征.XRD分析表明:700℃煅烧后Fe3O4表面包覆上了结晶良好的立方晶系的Gd2O3:Eu3+.TEM照片表明:所得的复合粒子具有明显的核壳结构和完美的球形,构成核的Fe3O4颗粒的尺寸在200～300 nm之间,Fe3...     

Improving barrier properties of polyethylene/Fe2O3-modified nanographene nanocomposites in a magnetic field

The present work aims at improving the barrier properties of high molecular weight Polyethylene/ graphene nanoplatelets (HMWPE/GnP) nanocomposites by aligning the embedded modified graphene nanoparticles in a magnetic field. Graphene nanoplatelets (GnP) were modified by magnetic Fe₂O₃ to produce Fe₂O₃-modified Graphene, GnP-mFe₂O₃. The magnetic properties of Fe₂O₃ were previously characterized by the vibrating sample magnetometer (VSM) method and resulting GnP-mFe₂O₃ nanoparticles were characterized by Fourier transform infrared (FTIR) analysis. HMWPE/GnP nanocomposites were prepared via melt mixing. The prepared nanocomposites were sheeted at high temperatures in a magnetic field using a hot press. The barrier properties of prepared films, HMWPE/GnP and HMWPE/GnP-mFe₂O₃ were characterized by carrying out a permeation to oxygen experiment as a function of GnP and GnP-mFe₂O₃ contents. A decrease in gas transmission rate (GTR) was observed for the samples after being subjected to the magnetic field compared to the non-treated sample. The results of differential scanning calorimetry (DSC) and field emission electron microscopy (FESEM) experiments confirmed the orientation of GnP-mFe₂O₃ nanoparticles in nanocomposites.     

New metal complexes supported on Fe3O4 magnetic nanoparticles as recoverable catalysts for selective oxidation of sulfides to sulfoxides

Fe₃O₄ nanoparticles were coated with aminopropyltriethoxysilane and subsequently reacted with isatin to obtain imine‐bonded Fe₃O₄ nanoparticles. The addition of ZrOCl₂?8H₂O or CuCl₂ led to the formation of complexes of Zr(IV)/isatin@Fe₃O₄ or Cu (II)/isatin@Fe₃O₄ as new magnetically separable catalysts. The synthesized catalysts were characterized using various techniques. These catalysts are shown to be efficient for chemo‐selective oxidation of sulfides to sulfoxides using hydrogen peroxide as oxidative agent. This system has many advantages, such as excellent level of reusability of magnetic catalysts, high yields, simplicity of separation of catalysts using an external magnet, environmental benignity and ease of handling. Copyright © 2016 John Wiley & Sons, Ltd.     

ICP-AES法测定AuNiGd合金中的Ni、Gd、Pd、Fe和Bi

报道了采用ICP-AES法测定AuNiGd合金中Ni、 Gd、 Pd、 Fe、 Bi.对测定元素的波长、测定条件进行了选择;考察了基体和无机酸对测定的影响;在优化条件下,对试样进行测定,其相对标准偏差(n＝15) Ni 1.6%、 Gd 1.8%、 Pd 13%、 Fe 4.9%、 Bi 13%;回收率 Ni 98%～105%、 Gd 97%～99%、 Pd 101%～105%、 Fe 98%～104%、 Bi 104%～106%.     

聚乙二醇-四氧化三铁纳米粒子复合材料的结构、物理性质及应用

在β-环糊精作保护剂条件下, 制备了高对称的十八面体四氧化三铁(Fe₃O₄)纳米材料. 通过胶体化学方法, 合成了一系列不同起始计量比的聚乙二醇(PEG)和Fe₃O₄纳米粒子复合物(CM-1-CM-4). 这些PEG复合材料展示出重要特性: 首先, 它们的表面形貌依赖于Fe₃O₄的计量; 其次, PEG的熔化过程受Fe₃O₄的影响, 并且直接与Fe₃O₄的含量相关; 进一步研究表明, 除CM-4外, Fe₃O₄的引入导致PEG结晶度下降, 而且Fe₃O₄纳米粒子量越少, 降低幅度越大; 更为有趣的是, PEG的降解过程受制于Fe₃O₄纳米粒子的影响, 导致不同降解产物的出现; 而且, 与纯Fe₃O₄纳米粒子一样, 复合材料中的Fe₃O₄也显示典型的软铁磁性行为, 但饱和磁化强度相对较小; 此外, X射线光电子能谱(XPS)实验揭示在这些PEG复合材料中, 有从Fe到O的电子转移, Fe电子密度的降低可用来解释复合材料饱和磁化强度的减小; 最后, 这些PEG复合材料呈现出对有机染料的表面增强拉曼效应, 并且这种效应随Fe₃O₄纳米粒子含量的增加而增加. 这些结果将会对聚合物/无机纳米粒子复合材料的发展起到推进作用.     

Waste to wealth: conversion of nano‐magnetic eggshell (Fe3O4@Eggshell) to Fe3O4@Ca(HSO4)2: cheap,green and environment‐friendly solid acid catalyst

Eggshell is a hazardous waste by European Union regulations, so that discarded thousands of tons per year. To convert waste (eggshell) to wealth (catalyst), nano‐magnetic eggshell was prepared based on the nano‐Fe₃O₄, and then the eggshell was converted to Ca(HSO₄)₂ with organic acid, namely, chlorosulfonic acid. Based on the back titration, 5.18 mmol SO₄H group was loaded per gram of the nano‐structure. Using this method eggshell was converted to cheap, green and environment‐friendly solid acid catalyst. The prepared catalyst (nano‐ Fe₃O₄@Ca(HSO₄)₂) was characterized by Fourier transform infrared spectroscopy (FT‐IR), X‐ray diffraction (XRD), energy dispersive X‐ray spectroscopy (EDX), field emission scanning electron microscopy (FE‐SEM), transmission electron microscopy (TEM), vibrating sample magnetometer (VSM), and thermal gravimetric analysis (TGA). The activity of eggshell waste‐derived catalysts was successfully evaluated in the synthesis of value‐added products, namely indazolo[1,2‐b]‐phthalazinetrione derivatives as a benchmark multicomponent reaction. In addition, design of experiments shows that increase in amount of catalyst (and temperature), boost the reaction yield, especially with steeper slope at higher temperature.     

Synthesis,characterization, and catalytic application of Fe3O4‐Si‐[CH2]3‐N=CH‐aryl for the efficient synthesis of novel poly‐substituted pyridines

Fe₃O₄ magnetic nanoparticles (MNPs) were functionalized by aminopropylsilane and reacted with aromatic aldehyde, and Fe₃O₄‐Si‐[CH₂]₃‐N=CH‐Aryl and Fe₃O₄‐Si‐(CH₂)₃‐NH‐CH₂‐Aryl MNPs were prepared as novel magnetic nanocatalysts. Fourier transform infrared (FT‐IR), X‐ray diffraction (XRD), and scanning and transmission electron microscopy (SEM and TEM) were used to identify the MNPs. The catalytic activity of the MNPs was evaluated in the one‐pot synthesis of some novel poly‐substituted pyridine derivatives.     

稀土Dy3+掺杂Fe3O4的合成及电磁性质

通过溶胶-凝胶法，合成了稀土Dy^3＋掺杂的Fe3O4样品，研究了掺杂对电磁性质的影响。通过X射线衍射分析发现，由于离子半径的不匹配，Fe3O4中稀土离子的高浓度掺杂不能实现，仅有极少量的稀土离子取代了Fe3O4中的Fe^3＋。通过振动样品磁强计对磁性质进行了表征，掺杂引起样品饱和磁化强度发生变化，这可能是因为Dy^3＋取代引起的磁化强度增加和杂相引起的磁化强度降低共同作用的结果。四电极法研究隧道磁阻发现，磁阻与掺杂量的关系表现出降低-升高-降低的特殊变化规律。这主要是由于掺杂Fe3O4自旋极化率降低导致隧穿磁阻下降，同时，掺杂Fe3O4在隧穿颗粒体系中实现了第二相即绝缘相的同步合成，第二相的出现有利于隧穿磁阻的增加。     

Research on WPU‐RGO/ATP‐Fe3O4/chitosan composites with excellent electrical and magnetic properties

First, attapulgite‐Fe₃O₄ magnetic filler (ATP‐Fe₃O₄) was prepared by using a chemical precipitation method. Subsequently, graphite oxide (GO) was prepared through Hummer method, and then reduced GO (RGO) was prepared through GO reduced by chitosan (CS). Finally, a series of WPU‐RGO/ATP‐Fe₃O₄/CS composites were prepared by introduced RGO/ATP‐Fe₃O₄/CS to waterborne polyurethane. The structure and properties were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), X‐ray diffraction (XRD), vibrating sample magnetometry (VSM), thermogravimetric analysis TGA, conductivity test, and tensile test. The experimental results indicated that thermal stability and tensile strength of nanocomposites were improved with the increase of the content of RGO/ATP‐Fe₃O₄/CS. Meanwhile, with the increase of the RGO/ATP‐Fe₃O₄/CS content, the electrical and magnetic properties of WPU‐RGO/ATP‐Fe₃O₄/CS composites were improved. When the content of RGO/ATP‐Fe₃O₄/CS was 8 wt%, the electrical conductivity and the saturation magnetic strength of WPU‐RGO/ATP‐Fe₃O₄/CS composites were 3.1 × 10^?7 S·cm^?1 and 1.38 emu/g, respectively. WPU‐RGO/ATP‐Fe₃O₄/CS composites have excellent electrical and magnetic properties.     

Synthesis,crystal structure,and magnetic properties of a new Fe(II) complex with reduced radical ligands

A new Fe(II) complex, [Fe(HIM2Py)₂(N(CN)₂)₂]?·?2H₂O (HIM2py?=?1-hydroxyl-2(2′-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1?H-imidazole), has been synthesized and characterized. The X-ray analysis reveals that HIM2py ligands are coordinated to iron as an unusual six-membered bidentate chelate with κ²N(py), O(HIM) mode. The variable-temperature magnetic susceptibility suggests that weak antiferromagnetic interactions exist in the complex.     

Fe_3O_4磁性纳米粒子催化动力学荧光法测定微量过氧化氢

Fe3O4磁性纳米粒子(Fe3O4MNPs)具有模拟过氧化氢酶的催化特性。基于Fe3O4MNPs催化H2O2氧化吡罗红建立了催化动力学荧光法测定H2O2的方法。对Fe3O4MNPs-吡罗红-H2O2体系的荧光光谱进行了研究,并考查了一些因素对体系的影响。所研究的催化反应分别在7~13min和13~18min内为假零级反应,对应的表观速率常数分别为1.33×10-1s-1和8.41×10-2s-1。反应时间为18 min时,催化反应的表观活化能为40.42 k J·mol-1。在最佳实验条件下,方法的线性范围为3.20×10-4~1.12×10-2mol·L-1,检出限为1.65×10-4mol·L-1。该法可用于消毒液、雨水、自来水及合成样品中H2O2含量的测定。     

Synthesis,characterization and properties of multifunctional poly(arylene ether nitriles) (PEN)/CNTs/Fe3O4 nanocomposites

In this study, a novel multifunctional poly(arylene ether nitriles)(PEN)/carbon nanotubes/Fe₃O₄ nanocomposite with high tensile strength, magnetic, and electrical properties was investigated. First, we synthesized the monodisperse Fe₃O₄ nanoparticles on the surface of the multiwalled carbon nanotubes and then the hybrid material was compounded with PEN through the solution‐casting method. The SEM and TEM images indicated that the monodisperse Fe₃O₄ nanoparticles, with the diameters of 70∼80 nm, were self‐assembled along CNTs via the covalent bond method, which was confirmed by FTIR and XRD. The results of tensile properties showed that the tensile strength and modulus reached their highest values at the CNTs/Fe₃O₄ loading content of 1 wt % and both were greatly enhanced after heat treatment. Electrical conductivity of the polymer was dramatically enhanced at the low loading level of CNTs/Fe₃O₄; the electrical percolation of was in the range of 5∼8 wt % of CNTs/Fe₃O₄. The magnetic study showed that the saturation magnetization (M_s) of PEN/CNTs/Fe₃O₄ nanocomposites increased with the increase of CNTs/Fe₃O₄ loading content, and the coercive force (H_c) of the nanocomposite was independent of the CNTs/Fe₃O₄ content. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011     

Structural,optical and magnetic properties of chromium and manganese co-doped SnO2 nanoparticles

The rutile phase Sn_0.99-xMn_xCr_0.01O₂ (x = 0.00, 0.01, 0.03, 0.05 and 0.07) nanoparticles were synthesized by facile chemical co-precipitation method using poly ethylene glycol (PEG) as a capping agent. The samples were characterized by EDAX to confirm the expected stoichiometry. The X-ray diffraction (XRD), transmission electron microscopy (TEM) and Fourier transform infrared (FTIR) spectroscopy analyses of these samples showed the formation of impurity free crystals with a single phase rutile type tetragonal crystal structure as that of (P4₂/mnm) of SnO₂. Optical absorption spectra and corresponding Tauc's plots showed a redshift of the absorption edge in SnO₂ after being co-doped with Cr and Mn. The samples were examined for its magnetic property using vibrating sample magnetometer which indicated that transition of magnetic signals from ferromagnetic to the paramagnetic nature with inclusion of Mn content in SnO₂: Cr host matrix. The observed magnetic behavior is well supported with the bound magnetic polarons (BMPs) model.     

Structural and electrical properties of crystals of substituted polyaniline

The simultaneous polymerization and crystallization of aniline has been reported earlier. In this article, the X‐ray crystal structure analysis, SEM morphological analysis and electrical properties of such crystals of oligo‐polyanilines are being reported. The structural analysis shows a pseudo‐orthorhombic lattice. The SEM images reveal flaky and triangular growth habit with granular overgrowths on the surface. The bulk conductivities achieved vary from 10^?5 S/cm to 10^?7 S/cm as the oxidant concentration is reduced from 5 to 0.1%. The temperature dependence showed a transition point upto which there is a decrease in current and above which the current increases. The ESR studies reveal polarons involved in charge conduction and their concentration is proportional to the oxidant concentration. The X‐ray patterns, conductivities, and ESR results have been correlated with the degree of polymerization results obtained from GPC studies. © 2007 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 45: 1127–1137, 2007     

Improvement on physical properties of polyethersulfone membranes modified by poly(1‐vinylpyrrolidone) grafted magnetic Fe3O4@SiO2 nanoparticles

Polyethersulfone (PES) and poly(1‐vinylpyrrolidone) (PVP) were used to prepare ultrafiltration membranes with grafted Fe₃O₄ magnetic nanoparticles (PVP‐g‐Fe₃O₄@SiO₂). The structure of synthesized PVP‐g‐Fe₃O₄@SiO₂ was confirmed by FT‐IR and SEM analysis. Physical properties of blend membranes such as thermal resistance, Tensile strength, water uptake, and hydrophilicity were also investigated. Blended membranes of PES/PVP‐g‐Fe₃O₄@SiO₂ have exhibited higher thermal resistance due to increasing the modified nanoparticle content. The hydrophilicity of the synthesized PES/PVP‐g‐Fe₃O₄@SiO₂ membranes also improved by increasing the PVP‐g‐Fe₃O₄@SiO₂ content. As expected, increasing the hydrophilicity of blended membrane, caused enhancement of fouling resistance in membranes. Results showed that the content of PVP‐g‐Fe₃O₄@SiO₂ has different effects on the properties of synthesized composite membranes. Despite increasing the content of PVP‐g‐Fe₃O₄@SiO₂ has a negative effect on elongation, positive effects on maximum stress was observed. Moreover, the water uptake of synthesized membranes was significantly enhanced in comparison to other similar studies.     

Syntheses and Crystal Structures of Ca3Fe2(SeO3)6 and Sr3Fe2(SeO3)6

The new compounds M₃Fe₂(SeO₃)₆ (M = Ca, Sr) were obtained as crystalline precipitates from aqueous solutions of the respective ions, kept in Teflon-coated vessels at a temperature of 227(2)°C for several days. The crystal data are: space group R3 c, a = 8.531(2), 8.802(2) Å; c = 38.89(1), 39.00(1) Å; V = 2451.1, 2616.7 ų, Z = 6. The crystal structures have been refined by single-crystal X-ray diffraction methods to R1 = 0.021, 0.023; wR2 = 0.038, 0.039. The framework structure is built up by two types of FeO₆ octahedra as well as by MO₈ groups and SeO₃ trigonal pyramids by corner- and edge-linkage of the polyhedra.     

Pure and Gd-based Li,Na, Mn or Fe codoped ZnO nanoparticles: Insights into the magnetic and photocatalytic properties

The ferromagnetic and photocatalytic properties of pure ZnO, Zn_0.97Gd_0.01Li_0.02O, Zn_0.97Gd_0.01Na_0.02O, Zn_0.97Gd_0.01Mn_0.02O and Zn_0.97Gd_0.01Fe_0.02O nanoparticles prepared by sol-gel technique were investigated. The XRD, EDX, HR-TEM, FTIR and diffuse reflectance analyses confirm the formation of single phase ZnO wurtzite structure with effective incorporation of Gd/Li, Na, Mn or Fe ions into ZnO host lattice. Based on Kubelka-Munk equation, the optical band gap of pure ZnO nanoparticles was estimated to be 3.22 eV and implantation of Gd-based dual dopants induces red shifts between 0.01 and 0.29 eV. For pure ZnO nanoparticles, noticeable ferromagnetic performance was observed with saturation magnetization of 0.0133 emu/g and coercivity of 85 Oe. The binary dopants of Gd/Mn or Na induce strong enhancements in the saturation magnetization of pure ZnO nanoparticles. Where, Zn_0.97Gd_0.01Na_0.02O and Zn_0.97Gd_0.01Mn_0.02O samples exhibited perfect hysteresis loops with saturation magnetization of 0.34 and 0.717 emu/g, respectively. Higher photocatalytic activity, 97%, for methyl orange degradation was observed for Zn_0.97Gd_0.01Na_0.02O nanoparticles within 210 min under UV irradiation. The particles size and agglomeration, ionic radii of dopants and recombination centers have main effects on the photocatalytic activity performance of ZnO nanoparticles. The dual dopants of Gd/Mn efficiently trigger the room temperature ferromagnetism of the pure ZnO; but Gd/Na blend revealed the best effect in methyl orange degradation (97%).     

Assembly and Post-modification of Fe3O4@MIL-100(Fe) for Knoevenagel Condensation

Many efforts have been devoted to the integration of magnetic nanoparticles and metal organic frameworks, which makes it easy and simple to separate the nano-sized metal organic frameworks from liquid phase. Amino-functionalized magnetic metal organic frameworks[Fe₃O₄@MIL-100(Fe)-NH₂]were prepared by a stepwise assembly method followed by post-modification with electron-rich reagent. This magnetic catalyst was characterized by means of X-ray diffraction(XRD), transmission electron microscopy(TEM), scanning electron microscopy(SEM) and nitrogen adsorption, and tested in Knoevenagel condensation as a base catalyst. The magnetic catalyst exhibits a core-shell structure and can afford a high activity for the Knoevenagel condensation due to its bifunctional property and reduced diffusion limitation. Furthermore, it could be recovered magnetically and recycled three times. Although activity loss was observed in the recycle experiments, it could be reactivated by dispersing in a fresh modifier solution.     

Enhanced photocatalytic Cr(VI) reduction and diclofenac sodium degradation under simulated sunlight irradiation over MIL-100(Fe)/g-C3N4 heterojunctions

Metal-organic framework MIL-100(Fe) and g-C₃N₄ heterojunctions (MG-x, x = 5%, 10%, 20%, and 30%, x is the mass fraction of MIL-100(Fe) in the hybrids) were facilely fabricated through ball-milling and annealing, and characterized by powder X-ray diffraction, Fourier transform infrared spectroscopy, thermogravimetric analysis, transmission electron microscopy, UV-visible diffuse-reflectance spectrometry, and photoluminescence emission spectrometry. The photocatalytic activities of the series of MG-x heterojunctions toward Cr(VI) reduction and diclofenac sodium degradation were tested upon irradiation with simulated sunlight. The influence of different organic compounds (ethanol, citric acid, oxalic acid, and diclofenac sodium) as hole scavengers and the pH values (2, 3, 4, 6, and 8) on the photocatalytic activities of the series of MG-x heterojunctions was investigated. MG-20% showed superior photocatalytic Cr(VI) reduction and diclofenac sodium degradation performance than did the individual MIL-100(Fe) and g-C₃N₄ because of the improved separation of photoinduced electron-hole charges, which was clarified via photoluminescence emission and electrochemical data. Moreover, the MG-x exhibited good reusability and stability after several runs.