Fe3O4@MCM-48–SO3H:合成苯并[f]色烯并[2,3-d]嘧啶酮的高效、可磁性分离纳米催化剂（英文）

Sulfonic acid groups were grafted onto three different types of synthesized magnetic nanoparticles, namely Fe3O4, Fe3O4@SiO2, and Fe3O4@MCM‐48. The sulfonic acid‐functionalized nanoparticles were evaluated as catalysts for the synthesis of 5‐aryl‐1H‐benzo[f]chromeno[2,3‐d]pyrimidine‐2,4(3H,5H)‐dione derivatives in terms of activity and recyclability. Their catalytic activities were compared with that of the homogeneous acid catalyst 1‐methylimidazolium hydrogen sulfate ([HMIm][HSO4]). The activity of Fe3O4@MCM‐48–SO3H was comparable to those of the other heter‐ogeneous and homogeneous catalysts.     

Size-controlled syntheses and hydrophilic surface modification of Fe3O4, Ag, and Fe3O4/Ag heterodimer nanocrystals

High-quality, monodisperse, and size-controlled Fe(3)O(4), Ag, and bifunctional Fe(3)O(4)/Ag heterodimer nanocrystals (NCs) have been synthesized successfully. In the synthesis of Fe(3)O(4) NCs, dodecanol was chosen as the substitute of 1,2-hexadecanediol and "size control" was achieved by simply adjusting the proportion among the ligands instead of utilizing seed-mediated growth. In the synthesis of Ag NCs, organometallic silver acetylacetonate (Agacac) was used as precursors and tunable particle size could be easily obtained by adjusting the reaction temperatures. By using different sized Fe(3)O(4) NCs as seeds, Fe(3)O(4)/Ag heterodimer NCs with particle sizes tuned from 5 to 16 nm for Fe(3)O(4) and 4 to 8 nm for Ag were successfully synthesized and superparamagnetism were maintained. We found that the size of Ag attached on the Fe(3)O(4) NCs relied on the size of Fe(3)O(4) seed. UV-vis absorption spectra and TEM investigations revealed that the bigger the Fe(3)O(4) NCs seed used, the bigger the Ag NCs that were obtained from the heterodimer NCs. In addition, we demonstrated that all of these NCs were successfully transferred into water by surface modification with biocompatible carboxylic acid groups, which made them meet the basic requirement for biolabeling and biomedical applications.     

纳米磁性固体酸SO42-/Zr（OH）4-Fe3O4催化水相不对称Aldol反应

以纳米磁性材料Fe3O4, ZrOCl2·8H2O和硫酸为原料,在不同焙烧温度下制备了纳米磁性固体酸催化剂SO42–/Zr(OH)4-Fe3O4.详细表征了该磁性固体酸的SO42–负载量、酸分布、表面形貌和孔结构等特性.在含有硝基和氰基强吸电子基苯甲醛的不对称水相Aldol反应中, SO42–/Zr(OH)4-Fe3O4表现出优良的催化性能(83%–100%收率,86.0%–95.6% eeanti和anti/syn =88–96/12–4).该类磁性固体酸可在外加磁体作用下定量地从催化反应体系中分离并回收使用,重复使用5次未见显著失活.     

Fe3O4-LiMo3Se3 nanoparticle clusters as superparamagnetic nanocompasses

A scaleable chemical approach to functional nanoscale analogues of the magnetic compasses in magnetotactic bacteria is described. LiMo(3)Se(3)-Fe(3)O(4) nanowire-nanoparticle composites were synthesized by a reaction of 3-iodopropionic acid treated LiMo(3)Se(3) nanowire bundles with oleic acid-stabilized Fe(3)O(4) nanoparticles of 2.8, 5.3, and 12.5 nm size in tetrahydrofuran. Transmission electron micrographs show that the composite consists of Fe(3)O(4) nanoparticles attached to the surfaces of the 4-6 nm thick nanowire bundles. UV/vis spectra reveal absorptions from the nanowire (506 nm) and magnetite components (280-450 nm), and IR spectra show characteristic bands for the propionic acid linkers and for the residual oleic acid ligands on the magnetite particles. In the presence of excess oleic acid, the nanocomposites undergo rapid disassembly, suggesting that Fe(3)O(4) nanoparticles are bonded to nanowires via carboxylate groups from the linkers. Ultrasonication of a dispersion of the composite in THF produces individual LiMo(3)Se(3)-Fe(3)O(4) clusters, which are 340 +/- 107 nm long and 20 +/- 5 nm thick, depending on the sonication time and Fe(3)O(4) nanoparticle size. Field cooled and zero-field cooled magnetization measurements reveal that the blocking temperature (T(B) = 100 K) of the clusters with 5.3 nm Fe(3)O(4) is increased as compared to the free nanoparticles (T(B) = 30 K). Directional dipolar interactions in the clusters lead to magnetic anisotropy, which makes it possible to align the clusters in a magnetic field (900 Oe).     

纳米Fe3O4/聚苯乙烯均匀分散体系的制备及结构

用化学共沉淀法制备了Fe3O4纳米颗粒,以油酸为表面活性剂,苯乙烯为载液,制备了稳定的纳米Fe3O4可聚合磁流体,将可聚合磁流体经自由基引发聚合制成纳米Fe3O4/聚苯乙烯均匀分散体系,用WAXRD研究了Fe3O4纳米粒子的结晶情况;用FTIR研究了油酸表面改性前后Fe3O4粒子表面官能团的变化;用TEM研究了Fe3O4颗粒的粒径大小及其在苯乙烯单体和聚苯乙烯中的分散情况;用DSC和TGA研究了纳米Fe3O4/聚苯乙烯均匀分散体系的玻璃化转变温度(Tg)和热稳定性,结果表明,合成的纳米Fe3O4为立方晶型,平均粒径在10nm左右,油酸分子在Fe3O4表面是化学吸附,经表面处理的Fe3O4超细颗粒在苯乙烯和聚苯乙烯基体中分散较均匀.界面粘结较好,含1.8％Fe3O4纳米颗粒的聚苯乙烯的最大热失重温度比聚苯乙烯提高了13K,Fe3O4/聚苯乙烯复合体系的饱和磁化强度σs为17.43emu/g.     

Selected-control synthesis of monodisperse fe(3) o(4) @c core-shell spheres, chains, and rings as high-performance anode materials for lithium-ion batteries

A method is reported for the first time for the selected-control, large-scale synthesis of monodispersed Fe(3) O(4) @C core-shell spheres, chains, and rings with tunable magnetic properties based on structural evolution from eccentric Fe(2) O(3) @poly(acrylic acid) core-shell nanoparticles. The Fe(3) O(4) @C core-shell spheres, chains, and rings were investigated as anode materials for lithium-ion batteries. Furthermore, a possible formation mechanism of Fe(3) O(4) @C core-shell chains and rings has also been proposed.     

Fe_3O_4/CdTe/聚氨酯纳米复合物的制备及其性能研究

由共沉淀法和Stober法制备了伯胺基功能化SiO2稳定的Fe3O4磁性纳米粒子Fe3O4@SiO2-NH2;Fe3O4@SiO2-NH2与二异氰酸酯及咪唑阳离子二醇、聚乙二醇的反应使其表面形成阳离子型聚氨酯稳定层;通过阳离子型聚氨酯与CdTe量子点表面修饰的巯基乙酸间的电荷相互作用,制备得到了Fe3O4/CdTe/聚氨酯纳米复合物.用X射线衍射(XRD)、红外吸收光谱(FTIR)、热重分析(TGA)、透射电子显微镜(TEM)、磁强计(VSM)、紫外吸收光谱(UV)、荧光发射光谱(PL)表征了该纳米复合物的结构与性能.结果表明,CdTe量子点均匀地分散在Fe3O4@SiO2磁性纳米粒子周围,所得纳米复合物在溶剂中分散均匀,不团聚,且具有超顺磁性,并保持了CdTe量子点的荧光性能.     

Fabrication of superparamagnetic macroporous Fe3O4 and its derivates using colloidal crystals as templates

In this paper, we reported the preparation of superparamagnetic macroporous Fe(3)O(4) and its derivates using organic colloidal crystal as templates and their catalytic activity for chemical vapor deposition. The poly(styrene-methyl methacrylate-acrylic acid) (P(St-MMA-AA)) copolymer colloids were deposited in an orderly manner onto the silicon surface, together with the infiltration of the Fe(3)O(4) nanoparticles into the interspaces of the colloids. The formed hybrid colloidal crystal subsequently was immersed in tetrahydrofuran to remove the organic components fully to obtain a macroporous Fe(3)O(4) framework with three-dimensional porous structure. The macroporous Fe(3)O(4) exhibits superparamagnetism due to the magnetic coupling of Fe(3)O(4) nanoparticles in the structure. Macroporous Fe(2)O(3) and Fe materials were obtained based on oxidization and reduction of the macroporous Fe(3)O(4), respectively. It was demonstrated that the macroporous Fe(3)O(4) materials possess catalytic activity and can induce growth of carbon nanotubes.     

锂离子电池复合正极材料xLiFePO4·yLi3V2(PO4)3的复合机制

以FePO4·xH2O、V2O5、NH4H2PO4和Li2CO3为原料, 以乙二酸为还原剂, 通过湿化学还原-低温热处理方法制备出锂离子复合正极材料xLiFePO4·yLi3V2(PO4)3. X射线衍射(XRD)结果表明, 合成的材料中橄榄石结构的LiFePO4和单斜晶系的Li3V2(PO4)3两相共存; 从复合材料中LiFePO4、Li3V2(PO4)3相对于相同条件下制备的纯相LiFePO4和Li3V2(PO4)3的晶格常数变化以及结合高分辨透射电子显微镜(HRTEM)、能量散射X射线(EDAX)的结果可以看出, 在复合材料xLiFePO4·yLi3V2(PO4)3中存在部分V和Fe, 分别掺杂在LiFePO4和Li3V2(PO4)3中, 并形成固溶体; X射线光电子能谱(XPS)结果表明, Fe/V在复合材料中的价态与各自在LiFePO4和Li3V2(PO4)3中的价态保持一致, 分别为+2 和+3价. 充放电测试表明, 制备出的复合正极材料电化学性能明显优于单一的LiFePO4和Li3V2(PO4)3; 循环伏安测试表明, 复合正极材料具有优良的脱/嵌锂性能.     

Fe3O4/Polypyrrole/Au nanocomposites with core/shell/shell structure: synthesis, characterization, and their electrochemical properties

Uniform Fe3O4 nanospheres with a diameter of 100 nm were rapidly prepared using a microwave solvothermal method. Then Fe304/polypyrrole (PPy) composite nanospheres with well-defined core/shell structures were obtained through chemical oxidative polymerization of pyrrole in the presence of Fe3O4; the average thickness of the coating shell was about 25 nm. Furthermore, by means of electrostatic interactions, plentiful gold nanoparticles with a diameter of 15 nm were assembled on the surface of Fe3O4/PPy to get Fe3O4/PPy/Au core/shell/shell structure. The morphology, structure, and composition of the products were characterized by transmission electronic microscopy (TEM), scanning electronic microscopy (SEM), X-ray powder diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The resultant nanocomposites not only have the magnetism of Fe3O4 nanoparticles that make the nanocomposites easily controlled by an external magnetic field but also have the good conductivity and excellent electrochemical and catalytic properties of PPy and Au nanoparticles. Furthermore, the nanocomposites showed excellent electrocatalytic activities to biospecies such as ascorbic acid (AA).     

Cube‐like 12‐MC‐4 and Offset Stacked 10‐MC‐3 Metallacrowns: Synthesis,Structure, and Magnetic Properties

Two complexes [Mn^III₄(naphthsao)₄(naphthsaoH)₄] ( 1 ) and [Fe^III₆O₂(naphthsao)₄(O₂CPh)₆] ( 2 ) [naphthsao = 1‐(1‐hydroxy‐naphthalen‐2‐yl)ethanone oxime] were obtained through the reactions of naphthsao ligand and MnCl₂ · 4H₂O or FeCl₃ · 6H₂O in the presence of triethylamine (Et₃N). Their structures were determined by X‐ray single crystal diffraction, elemental analysis, and IR spectra. Complex 1 displays 12‐MC‐4 metallacrown structural type with cube‐like configuration and 2 shows an offset stacked 10‐MC‐3 structural type with the ring connectivity containing Fe–O–C–O–Fe–O–N–Fe–O–N. Magnetic susceptibility measurement reveals the ferromagnetic interactions and field‐induced slow relaxation of the magnetization for 1 , whereas out‐of‐phase signal is not observed for 2 .     

铁-谷氨酸-硅钨酸三元配合物作为高活性非均相类Fenton催化剂降解4-氯酚

Fenton氧化法通过Fe2+离子催化分解H2O2产生羟基自由基,能够氧化降解绝大多数有机污染物.但是传统的均相Fenton氧化法使用高浓度二价铁盐作为催化剂,催化剂不便于回收利用,而且还会引发新的环境问题.另外,均相Fenton氧化法通常需要在pH约为3的酸性条件下进行,在较高pH条件下,有机物氧化降解速率降低,同时铁盐水解产生铁泥.文献报道了一些含铁固体材料作为非均相类Fenton催化剂,能够解决催化剂回收和重复利用问题,但是许多固体催化剂仍然只在酸性条件下表现出较高催化活性.多金属氧簇是除过渡金属氧化物之外的一类光催化剂.近年来,多金属氧簇在Fenton氧化过程中的应用开始受到关注.可以预计,含铁的多金属氧簇固体化合物有可能同时具有类Fenton催化活性和光催化活性.本文以三价铁盐(FeI I)、谷氨酸(Glu)和硅钨酸(SiW)为原料在水溶液中合成了一种不溶性的三元固体配合物FeШGluSiW,并用电感耦合等离子体原子发射光谱(ICP-AES)、热重分析(TG)、傅里叶变换红外光谱(FT-IR)、紫外-可见漫反射光谱(UV-vis DRS)、X射线衍射(XRD)和场发射扫描电镜(FE-SEM)对FeШGluSiW进行了表征.根据ICP-AES, TG和FT-IR结果推断, FeШGluSiW可能的化学组成为[Fe(C5H8NO4)(H2O)]2SiW12O40·13H2O,其中含有铁、谷氨酸根单元和Keggin结构的SiW12O404?阴离子. FE-SEM和XRD测试结果表明, FeШGluSiW是由结晶度较低、尺寸为100–200 nm的无规则颗粒组成,并含有无定形相.通过考察在自然初始pH 6.5条件下100 mg/L 4-氯酚(4-CP)在FeШGluSiW(1.0 g/L)/H2O2(20 mmol/L)体系中的氧化降解反应,我们发现在暗态和光照条件下,4-CP完全降解所需时间分别为40和15 min,延长反应时间至2 h,总有机碳(TOC)去除率分别达到27%和72%.结果表明, FeШGluSiW具有很高的催化活性,而且在光照条件下活性更高.进一步研究发现, FeШGluSiW在pH 3–6.5范围内均表现出高的催化活性,而且在酸性条件下活性更高.用ICP-AES测定Fe元素在溶液中的析出量,证实4-CP氧化降解主要发生在固体催化剂表面.在反应体系中加入正丁醇能显著抑制4-CP降解,说明4-CP降解反应涉及羟基自由基的氧化作用.在光照反应条件下,催化剂颜色明显变深,表明光照条件下的反应机理涉及催化剂中SiW12O404?阴离子的还原.考虑到催化剂中含有谷氨酸根和SiW12O404?杂多阴离子,推测H2O2有可能通过氢键吸附于催化剂表面,这可能是FeШGluSiW表现出高催化活性的重要原因.结合文献报道的含铁固体材料类Fenton催化机理和多金属氧簇光催化机理,可以很好地解释4-CP降解反应实验结果.在暗态条件下, FeШGluSiW的催化机理归因于催化剂表面FeII的氧化还原循环FeII?FeI,即H2O2分子在催化剂表面分解产生羟基自由基,从而导致4-CP氧化;而在光照条件下,除了催化剂中FeI I的类Fenton催化作用之外,催化剂中SiW12O404?杂多阴离子的光催化作用同时发生,导致4-CP降解速率加快.在光催化过程中,4-CP可以被激发态SiW12O404?直接氧化,也可以被激发态SiW12O404?与H2O相互作用产生的羟基自由基氧化.被还原的杂多阴离子可以被O2氧化,也可以被H2O2氧化,因而H2O2的存在也促进了FeШGluSiW的光催化作用.     

Poly­[iron(II)‐di‐μ‐imidazole‐4,5‐di­carboxyl­ato‐κ3N3,O4:O5]

In the title compound, [Fe(C₅H₃N₂O₄)₂]_n, each Fe atom lies on a centre of symmetry, in an octahedral coordination environment consisting of two chelate rings [Fe—N = 2.154 (3) Å and Fe—O = 2.180 (3) Å] and two carboxyl­ate O atoms [Fe—O = 2.111 (2) Å] from imidazole‐4,5‐di­carboxyl­ate ligands. Extensive hydrogen‐bonding interactions exist between layers constructed of Fe₄ squares, forming tunnels along the a axis with large voids.     

利用Fe3O4/DR膜作为催化剂前体在硅片上生长多壁碳纳米管

Fe3O4纳米粒子与正离子性的重氮树脂在硅基底的表面形成稳定自组装膜,还原后可通过化学气相沉积(CVD)法在硅基底的表面生长多壁碳纳米管.以聚丙烯酸包裹Fe3O4纳米颗粒能够有效地防止纳米粒子的团聚,并提高组装效率,得到均匀的纳米粒子自组装膜,从而获得在硅基底上均匀分布的多壁碳纳米管.     

Synthesis of Fe_3O_4@SiO_2@polymer nanoparticles for controlled drug release

Novel multifunctional nanoparticles containing a magnetic Fe3O4@SiO2 sphere and a biocompatible block copolymer poly(ethylene glycol)-b-poly(aspartate)(PEG-b-PAsp) were prepared.The silica coated on the superparamagnetic core was able to achieve a magnetic dispersivity,as well as to protect Fe3O4 against oxidation and acid corrosion.The PAsp block was grafted to the surface of Fe3O4@SiO2 nanoparticles by amido bonds,and the PEG block formed the outermost shell.The anticancer agent doxorubicin(DOX) was loade...     

无溶剂Fe3O4纳米流体的制备及表征

采用共沉淀法合成Fe3O4纳米粒子, 将含有硅氧烷基的离子型改性剂二甲基十八烷基氯化铵与Fe3O4纳米粒子进行接枝反应, 再用脂肪醇聚氧乙烯醚磺酸盐的长链阴离子交换Cl-, 在Fe3O4纳米粒子表面生成具有阴、 阳离子双电层结构的表面处理层, 得到无溶剂Fe3O4纳米流体. 研究结果表明, 在Fe3O4纳米粒子表面成功接枝了有机物长链, 改性的Fe3O4纳米粒子呈单分散分布, 其损耗剪切模量G″明显大于储能剪切模量G', 具有明显的流体行为, 在室温下即可流动.     

Cyano-bridged FeIII2CuII3 and FeIII4NiII4 complexes: syntheses, structures, and magnetic properties

Two tricyanometallate precursors, (Bu4N)[(Tp4Bo)Fe(CN)3].H2O.2MeCN (1) and (Bu4N)[(pzTp)Fe(CN)3] (2) [Bu4N+ = tetrabutylammonium cation; Tp4Bo = tris(indazolyl)hydroborate; pzTp = tetrakis(pyrazolyl)borate], with a low-spin FeIII center have been synthesized and characterized. The reactions of 1 or 2 with [Cu(Me3tacn)(H2O)2](ClO4)2 (Me3tacn = N,N',N' '-trimethyl-1,4,7-triazacyclononane) afford two pentanuclear cyano-bridged clusters, [(Tp4Bo)2(Me3tacn)3Cu3Fe2(CN)6](ClO4)4.5H2O (3) and [(pzTp)2(Me3tacn)3Cu3Fe2(CN)6](ClO4)4.4H2O (4), respectively. Assembly reactions between 2 and [Ni(phen)(CH3OH)4](ClO4)2 (phen = 1,10-phenanthroline) or Zn(OAc)2.2H2O afford a molecular box [(pzTp)4(phen)4Ni4Fe4(CH3OH)4(CN)12](ClO4)4.4H2O (5) and a rectangular cluster [(pzTp)2Zn2Fe2(OAc)2(H2O)2(CN)6] (6). Their molecular structures were determined by single-crystal X-ray diffraction. In complexes 1 and 2, the central FeIII ions are coordinated by three cyanide carbon atoms and three nitrogen atoms of Tp4Bo- or pzTp-. Both complexes 3 and 4 show a trigonal-bipyramidal geometry, in which [(L)Fe(CN)3]- units occupy the apical positions and are linked through cyanide to [Cu(Me3tacn)]2+ units situated in the equatorial plane. Complex 5 possesses a cubic arrangement of eight metal irons linked through edge-spanning cyanide bridges, while complex 6 shows Zn2Fe2(CN)4 rectangular structure, in which FeIII and ZnII ions are alternately bridged by the cyanide groups. Intramolecular ferromagnetic couplings are observed for complexes 3-5, and they have S = 5/2, 5/2, and 6 ground states and appreciable magnetic anisotropies with negative D values equal to -0.49, -2.39, and -0.39 cm-1, respectively.     

磁性纳米复合氧化物固体酸催化剂的制备及酯化性能

固体酸催化剂的无腐蚀、环境友好和可循环使用等特点使其成为无机液体酸的最佳替代物.磁性纳米固体酸具有优于常规固体酸催化剂的催化活性及分离简单的特性.用共沉淀法分别合成了一系列三组分TiO2-Al2O3-Fe3O4(TAF)和CeO2-Al2O3-Fe3O4(CAF)及四组分ZrO2--Al2O3-Fe3O4(ZACF)磁性纳米复合氧化物固体酸催化剂,通过电感耦合等离子体原子发射光谱、比表面积测定、X射线衍射、透射电镜、热重分析和红外光谱等对其进行了表征,并利用酯化反应作为探针反应评价了其催化性能.结果表明,合成的磁性纳米固体酸催化剂在酯化反应中表现出很好的催化活性.     

Pickering emulsions stabilized by surface-modified Fe3O4 nanoparticles

Unmodified Fe(3)O(4) nanoparticles do not stabilize Pickering emulsions of a polar oil like butyl butyrate. In order to obtain stable emulsions, the Fe(3)O(4) nanoparticles were modified by either carboxylic acid (RCOOH) or silane coupling agents (RSi(OC(2)H(5))(3)) to increase their hydrophobicity. The influence of such surface modification on the stability of the resultant Pickering emulsions was investigated in detail for both a non-polar oil (dodecane) and butyl butyrate in mixtures with water. The stability of dodecane-in-water emulsions in the presence of carboxylic acid-coated particles decreases as the length of the alkyl group (R) and the coating extent increase. However, such particles are incapable of stabilizing butyl butyrate-water emulsions even when the carboxylic acid length is decreased to two. However, the silane-coated Fe(3)O(4) nanoparticles can stabilize butyl butyrate-in-water emulsions, and they also increase the stability of dodecane-in-water emulsions. Thermal gravimetric analysis indicates that the molar quantity of silane reagent is much higher than that of carboxylic acid on nanoparticle surfaces after modification, raising their hydrophobicity and enabling enhanced stability of the resultant polar oil-water emulsions.     

磁性Fe_3O_4-聚吡咯纳米微球的合成与表征

报道了具有核壳结构的Fe3O4 聚吡咯磁性纳米微球的合成方法和表征结果 .微球同时具有导电性和磁性能 .在优化的实验条件下 ,可得到饱和磁化强度为 2 3 4emu g ,矫顽力为 45 2Oe的磁性微球 .微球的导电性随着微球中Fe3O4含量的增加而下降 .微球的磁性能则随着Fe3O4含量的增加而增大 .Fe3O4磁流体的粒径和磁性聚吡咯微球的粒径均在纳米量级 .纳米Fe3O4粒子能够提高复合物的热性能 .实验表明 ,磁流体和聚吡咯之间存在着一定的相互作用 ,正是这种相互作用使磁性聚吡咯纳米微球的热稳定性提高 .