Palladium magnetic nanoparticle‐polyethersulfone composite membrane as an efficient and versatile catalytic membrane reactor

Developing polymer catalytic membrane reactors is an aim due to its outstanding advantages. In this paper, a novel catalytic membrane containing palladium‐supported magnetic nanoparticles is introduced. Silica‐iron oxide core shell nanoparticles were first prepared and functionalized by phosphine ionic liquid functionalized poly(ethylene glycol). The modified magnetic nanoparticles were used as support for immobilization of palladium. The final palladium‐immobilized nanoparticles were used as active filler for the preparation of membrane reactor. The prepared membranes were characterized, and their activities were tested in carbon‐carbon bond formation and catalytic reduction. The catalytic membrane showed good performance in the mentioned reactions.     

磁性纳米粒子负载钯催化有机合成反应研究进展

磁性纳米粒子负载钯催化的有机合成反应,由于具有催化活性高,催化剂在外加磁场作用下即可快速分离和重复使用等特点,已引起了人们的广泛关注.综述了近年来磁性纳米粒子负载钯催化有机合成反应的研究进展,载体包括Fe3O4纳米粒子、有机小分子修饰的磁性纳米粒子、SiO2包覆的磁性纳米粒子、碳修饰磁性纳米粒子、羟基磷灰石包覆的磁性纳米粒子和有机高分子修饰的磁性纳米粒子等.     

Magnetically recoverable 2-(aminomethyl)phenols-modified nanoparticles as a catalyst for Knoevenagel condensation and carrier for palladium to catalytic Suzuki coupling reactions

A class of magnetic nanoparticles modified by 2-(aminomethyl)phenols has been successfully designed and synthesized as a reusable catalyst for Knoevenagel reaction. What's more, such nanomaterial also proved as suitable carrier for immobilization of palladium nanoparticles and the obtained composite exerted potent catalytic activity in Suzuki coupling reactions. Both of the (aminomethyl)phenols-modified nanoparticles and its related palladium nanocatalyst could be easily separated and reused for several consecutive runs by magnetic decantation without significant loss of their catalytic efficiency.     

Synthesis and characterization of molybdenum (VI) complex immobilized on polymeric Schiff base-coated magnetic nanoparticles as an efficient and retrievable nanocatalyst in olefin epoxidation reactions

In this study, a new polymeric functionalized magnetic nanocatalyst containing a molybdenum Schiff base complex was prepared using a few consecutive steps. Poly (methylacrylate)-coated magnetic nanoparticles were synthesized via radical polymerization of methyl acrylate onto modified magnetic nanoparticles followed by the amidation of the methyl ester groups with hydrazine. Polymeric functionalization efficiently provides the advantage that more catalytic units can be grafted on the surface of magnetic nanoparticles. The functionalization process was continued with salicylaldehyde which introduced Schiff base groups on to the surface of the polymeric support. In the final step, the desired catalytic system was prepared via complexation of the Schiff base groups with MoO₂(acac)₂. The resulting nanoparticles were characterized by infrared spectroscopy, powder X-ray diffraction, scanning and transmission electron microscopy, elemental analysis, inductively coupled plasma optical emission spectrometry, vibrating sample magnetometry and thermogravimetric analysis. This heterogenized catalytic system was also found to be highly active, sustainable and recyclable nanocatalyst in alkene epoxidation. Eventually, the attractive features of the synthesized catalyst such as simple work-up, good stability, magnetic separation, high TOF and high surface area; make it appropriate for oxidation reactions.     

Chemical routes for production of transition-metal phosphides on the nanoscale: implications for advanced magnetic and catalytic materials

Nanoparticulate transition-metal phosphides remain an unexplored, though emerging area of interest on the materials landscape, due principally to their promising magnetic and catalytic properties. This review describes synthetic strategies for the formation of both supported and unsupported transition-metal phosphide nanoparticles, provides a summary of their relevant magnetic and catalytic properties, and indicates new directions for exploration.     

Magnetically Induced Continuous CO2 Hydrogenation Using Composite Iron Carbide Nanoparticles of Exceptionally High Heating Power

The use of magnetic nanoparticles to convert electromagnetic energy into heat is known to be a key strategy for numerous biomedical applications but is also an approach of growing interest in the field of catalysis. The heating efficiency of magnetic nanoparticles is limited by the poor magnetic properties of most of them. Here we show that the new generation of iron carbide nanoparticles of controlled size and with over 80 % crystalline Fe_2.2C leads to exceptional heating properties, which are much better than the heating properties of currently available nanoparticles. Associated to catalytic metals (Ni, Ru), iron carbide nanoparticles submitted to magnetic excitation very efficiently catalyze CO₂ hydrogenation in a dedicated continuous‐flow reactor. Hence, we demonstrate that the concept of magnetically induced heterogeneous catalysis can be successfully applied to methanation of CO₂ and represents an approach of strategic interest in the context of intermittent energy storage and CO₂ recovery.     

Pd@tetrahedral hollow magnetic nanoparticles coated with N‐doped porous carbon as an efficient catalyst for hydrogenation of nitroarenes

Hollow magnetic nanoparticles (MNPs) with tetrahedral morphology were synthesized and then covered by a shell prepared by coating with melamine–formaldehyde followed by the introduction of glucose‐derived carbon. Subsequently, Pd nanoparticles were immobilized and the core–shell nanocomposite was carbonized. The obtained magnetic catalyst was successfully applied for the hydrogenation of nitroarenes in aqueous media. To investigate the effects of the morphology of MNPs, the nature of carbon shell, and the order of incorporation of Pd nanoparticles, several control catalysts, including the MNPs with different morphologies (disc‐like and cylinder); MNPs coated with different shells (sole glucose‐derived carbon or melamine–formaldehyde carbon shell); and a nanocomposite, in which Pd was immobilized after carbonization, were prepared and examined as catalyst for the model reaction. To justify the observed different catalytic activities of the catalysts, their Pd loadings, leaching, and specific surface areas were compared. The results confirmed that tetrahedral MNPs coated with porous N‐rich carbon shell exhibited the best catalytic activity. The high catalytic activity of this catalyst was attributed to its high surface area and the interaction of N‐rich shell with Pd nanoparticles that led to the higher Pd loading and suppressed Pd leaching.     

Phenylene‐Coated Magnetic Nanoparticles that Boost Aqueous Asymmetric Transfer Hydrogenation Reactions

Phenylene‐coated organorhodium‐functionalized magnetic nanoparticles are developed through co‐condensation of chiral 4‐(trimethoxysilyl)ethyl)phenylsulfonyl‐1,2‐diphenylethylene‐diamine and 1,4‐bis(triethyoxysilyl)benzene onto Fe₃O₄ followed complexation with [{Cp*RhCl₂}₂]. This magnetic catalyst exhibits excellent catalytic activity and high enantioselectivity in asymmetric transfer hydrogenation in aqueous medium. Such activity is attributed to the high hydrophobicity and the confined nature of the chiral organorhodium catalyst. The magnetic catalyst can be easily recovered by using a small external magnet and it can be reused for at least 10 times without loss of its catalytic activity. This characteristic makes it an attractive catalyst for environmentally friendly organic syntheses.     

Chloroaluminate ionic liquid‐modified silica‐coated magnetic nanoparticles: Efficient and reusable catalyst for selective synthesis of mono‐ and bis‐dihydropyrano[3,2‐b]chromenediones

The synthesis, characterization and catalytic activity of chloroaluminate ionic liquid‐modified silica‐coated magnetic nanoparticles ([SiPrPy]AlCl₄@MNPs) are described. The prepared magnetic nanocatalyst was characterized using Fourier transform infrared spectroscopy, elemental analysis, vibrating sample magnetometry, scanning and transmission electron microscopies, X‐ray diffraction and inductively coupled plasma analysis. The results showed that the ionic liquid had been successfully immobilized onto the magnetic support, and the resulting nanoparticles exhibited high catalytic activity for the synthesis of a diverse range of dihydropyrano[3,2‐b ]chromenediones via a one‐pot, three‐component and solvent‐free reaction of aromatic aldehydes, 1,3‐diones and kojic acid. This catalytic system also showed excellent activity in the selective synthesis of mono‐ and bis‐dihydropyrano[3,2‐b ]chromenediones from dialdehydes. The procedure gave the products in excellent yields and in very short reaction times. Moreover, the catalyst could be reused eight times without loss of its catalytic activity.     

Cu (II)‐β‐cyclodextrin complex stabilized on magnetic nanoparticles: A retrievable hybrid promoter for green synthesis of spiropyrans

The magnetic core of manganese ferrite (MnFe₂O₄) nanoparticles has a significant stability in comparison with ferrite (Fe₃O₄) nanoparticles. The unique supramolecular properties of β‐cyclodextrin (β‐CD), such as hydrophobic cavity, hydrophilic exterior and ‐OH functional groups, make it a good candidate for functionalization and catalytic application. So, a surface‐modified magnetic solid support with the Cu (II)‐β‐CD complex was prepared. The structure of nanoparticles was characterized by Fourier transform‐infrared spectroscopy, X‐ray powder diffraction, thermogravimetric analysis, vibrating‐sample magnetometry, inductively coupled plasma‐optical emission spectrometry and scanning electron microscope analyses. The catalytic activity of these nanoparticles was investigated in the synthesis of spiropyrans and high yields of desired products obtained under green media. Some advantages of this novel catalyst for this reaction are high yields, short reaction times, green solvent and conditions, easy workup procedure, negligible copper leaching, reusability without a significant diminish in catalytic efficiency, and simple separation of nanocatalyst by using an external magnet alongside the environmental compatibility and sustainability.     

Sulfamic acid heterogenized on functionalized magnetic Fe3O4 nanoparticles with diaminoglyoxime as a green,efficient and reusable catalyst for one‐pot synthesis of substituted pyrroles in aqueous phase

Surface functionalization of magnetic nanoparticles is an elegant way to bridge the gap between heterogeneous and homogeneous catalysis. We have conveniently loaded sulfonic acid groups on amino‐functionalized Fe₃O₄ nanoparticles affording sulfamic acid‐functionalized magnetic Fe₃O₄ nanoparticles (MNPs/DAG‐SO₃H) as an active and stable magnetically separable acidic nanocatalyst, which was characterized using X‐ray diffraction, Fourier transform infrared and energy‐dispersive X‐ray spectroscopies, scanning and transmission electron microscopies, vibrating sample magnetometry and elemental analysis. The catalytic activity of MNPs/DAG‐SO₃H was probed through one‐pot synthesis of N‐substituted pyrroles from γ‐diketones and primary amines in aqueous phase at room temperature. The heterogeneous catalyst could be recovered easily by applying an external magnet device and reused many times without significant loss of its catalytic activity. Copyright © 2014 John Wiley & Sons, Ltd.     

Polyol法制备PEO-PPO-PEO包裹的多功能CoFeAu纳米粒子(英文)

采用Polyol合成法,以三嵌段共聚物PEO-PPO-PEO为表面活性剂,以1,2-十六烷二醇为还原剂,乙酰丙酮钴(Ⅱ)、乙酰丙酮铁(Ⅱ)和醋酸金为前驱体,成功合成了CoFeAu纳米粒子.傅立叶变换红外光谱(FT-IR)分析证实了共聚物PEO-PPO-PEO包裹在CoFeAu纳米颗粒表面,X射线衍射仪(XRD)测试得出该纳米粒子是面心立方晶体结构、晶格参数为0.406nm、结晶性能好.紫外可见近红外分光光度计吸收光谱仪和振动样品磁强计(VSM)测试证明了该纳米粒子兼具良好的光学和磁学特性.该多功能CoFeAu纳米粒子有望在催化材料、磁材料、光电和生物医药等方面发挥有益作用.     

磁性印迹纳米粒子固定血红蛋白修饰磁性电极构建过氧化氢传感器

采用表面印迹技术,以磁性二氧化硅纳米粒子（Fe₃O₄@SiO₂ NPs）作为载体、血红蛋白（Hb）为模板分子、正硅酸乙酯（TEOS）为印迹聚合物单体,制备了Hb印迹Fe₃O₄@SiO₂的磁性印迹纳米粒子（MMIPs NPs）. MMIPs NPs具有磁性内核和血红蛋白印迹壳层的核壳结构,可以富集并固定Hb. 使用壳聚糖将MMIPs NPs固定于磁性电极表面,构建血红蛋白类酶生物传感器,研究了Hb对过氧化氢（H₂O₂）的催化活性. MMIPS NPS相比于磁性非印迹纳米粒子（MNIPS NPS）,催化电流增加了14.3%. 采用磁性电极,MMIPS NPS、Hb和O₂的顺磁性使得该类酶生物传感器对H₂O₂的催化电流增加了60.0%. 血红蛋白类酶生物传感器电流响应与H₂O₂浓度在25 ~ 200 μmol·L^-1间呈线性关系,检出限为3 μmol·L^-1（S/N=3）,表明该类酶传感器对H₂O₂具有良好的催化性能.     

Superassembled Hierarchical Asymmetric Magnetic Mesoporous Nanorobots Driven by Smart Confined Catalytic Degradation

Micro/nanoscale robotics has received great attention in many important fields. However, it is still a great challenge to construct nanorobots simultaneously possessing multifunctionality, well-controlled directionality, and fast and durable motion as well as fully compatible and biodegradable components. Here, a hierarchical, asymmetric, hollow, catalytic, magnetic, and mesoporous nanorobot has been fabricated through a multistep interfacial superassembly strategy. The multilayer composites consist of hollow silica nanoflasks sequentially coated with a highly magnetic responsive Fe₃O₄ layer, a mesoporous silica layer with homogeneous vertical channels, and a layer of catalytic gold nanoparticles on both the inner and outer surfaces. Furthermore, para-nitrophenol was used as a model pollutant to trigger self-motility of the nanoflasks by confined catalytic degradation (CCD). We found that the bottleneck morphology and mesoporous surface both improved the catalytic nanoparticle loading capability and CCD effect, thus enabling efficient self-motility and a durable movement capacity of ∼100 h. In addition, the catalytic performance was improved by 180 % compared with that of solid spherical nanoparticles.     

Tuning of Magnetic Hyperthermia Response in the Systems Containing Magnetosomes

A number of materials are studied in the field of magnetic hyperthermia. In general, the most promising ones appear to be iron oxide particle nanosystems. This is also indicated in some clinical trial studies where iron-based oxides were used. On the other hand, the type of material itself provides a number of variations on how to tune hyperthermia indicators. In this paper, magnetite nanoparticles in various forms were analyzed. The nanoparticles differed in the core size as well as in the form of their arrangement. The arrangement was determined by the nature of the surfactant. The individual particles were covered chemically by dextran; in the case of chain-like particles, they were encapsulated naturally in a lipid bilayer. It was shown that in the case of chain-like nanoparticles, except for relaxation, a contribution from magnetic hysteresis to the heating process also appears. The influence of the chosen methodology of magnetic field generation was also analyzed. In addition, the influence of the chosen methodology of magnetic field generation was analyzed. The application of a rotating magnetic field was shown to be more efficient in generating heat than the application of an alternating magnetic field. However, the degree of efficiency depended on the arrangement of the magnetite nanoparticles. The difference in the efficiency of the rotating magnetic field versus the alternating magnetic field was much more pronounced for individual nanoparticles (in the form of a magnetic fluid) than for systems containing chain nanoparticles (magnetosomes and a mix of magnetic fluid with magnetosomes in a ratio 1:1).     

Protease Immobilization on γ‐Fe2O3/Fe3O4 Magnetic Nanoparticles for the Synthesis of Oligopeptides in Organic Solvents

The use of nanobiocatalysts, with the combination of nanotechnology and biotechnology, is considered as an exciting and rapidly emerging area. The use of iron oxide magnetic nanoparticles, as enzyme immobilization carriers, has drawn great attention because of their unique properties, such as controllable particle size, large surface area, modifiable surface, and easy recovery. In this study, various γ‐Fe₂O₃/Fe₃O₄ magnetic nanoparticles with immobilized proteases were successfully prepared by three different immobilization strategies including A) direct binding, B) with thiophene as a linker, and C) with triazole as a linker. The oligopeptides syntheses catalyzed by these magnetic nanoparticles (MNPs) with immobilized proteases were systematically studied. Our results show that i) for magnetic nanoparticles immobilized α‐chymotrypsin, both immobilization strategies A and B furnished good reusability for the Z‐Tyr‐Gly‐Gly‐OEt synthesis, the MNPs enzymes can be readily used at least five times without significant loss of its catalytic performance: ii) In the case of Z‐Asp‐Phe‐OMe synthesis catalyzed by magnetic nanoparticles immobilized thermolysin, immobilization Strategy B provided the best recyclability: iii) For the immobilized papain, although Strategy A or B afforded an immobilized enzyme for the first cycle of Z‐Ala‐Leu‐NHNHPh synthesis in good yield, their subsequent catalytic activity decreased rapidly. In general, the γ‐Fe₂O₃ MNPs were better for use as an immobilization matrix, rather than the Fe₃O₄ MNPs, owing to their smaller particle size and higher surface area.     

Copper/Schiff-base complex immobilized on amine functionalized silica mesoporous magnetic nanoparticles under solvent-free condition: A facile and new avenue for the synthesis of thiazolidin-4-ones

A copper/Schiff-base complex supported on amine-functionalized silica mesoporous magnetic nanoparticles was prepared as novel magnetically interphase nanoparticles and its morphology and structure were evaluated using Fourier transform infrared spectroscopy, X-ray diffraction, field emission scanning electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, thermogravimetric analysis, zeta potential, and a vibrating sample magnetometer. The catalytic activity of the synthesized nanoparticles was evaluated for the synthesis of thiazolidine-4-ones.     

Zinc cation supported on carrageenan magnetic nanoparticles: A novel,green and efficient catalytic system for one‐pot three‐component synthesis of quinoline derivatives

This is the first report of supporting zinc cation on ƛ‐carrageenan/Fe₃O₄ magnetic nanoparticles. The structural and magnetic properties of this hybrid (Zn²⁺/ƛ‐carrageenan/Fe₃O₄ nanoparticles) were identified using various techniques. This green and efficient catalytic system was applied in the synthesis of biologically important quinolines. The products were obtained in good to high yields (52–95%) from a one‐pot reaction procedure involving aromatic aldehydes, enolizable aldehydes and aniline derivatives. Our method has many advantages such as mild reaction conditions, easy work‐up, use of a reusable magnetic catalyst and high yields of products.     

A magnetic nanoparticle‐catalyzed regioselective ring opening of epoxides by aromatic amines

Sulfonic acid‐functionalized silica‐coated magnetic Fe₃O₄ nanoparticles were synthesized and applied as a green catalyst for an efficient and environmentally friendly ring opening of epoxides with aromatic amines in good to excellent yields with high chemoselectivity. Clean aminolysis of various aliphatic and aromatic epoxides in ethanol generates β‐hydroxyamines under mild reaction conditions. The synthesized acidic magnetic nanoparticles were recovered using a simple external magnet and successfully reused for five runs without any appreciable loss of catalytic activity. Copyright © 2016 John Wiley & Sons, Ltd.     

Copper(I)–creatine complex on magnetic nanoparticles as a green catalyst for N- and O-arylation in deep eutectic solvent

Immobilization of copper(I) ions on magnetic nanoparticles was performed using surface modification of Fe₃O₄ with creatine. Fe₃O₄@creatine-Cu(I) magnetic catalyst was synthesized and applied in C&bond;X cross-coupling reactions with aryl halides in a deep eutectic as a green solvent. The results indicate the Fe₃O₄@creatine-Cu(I) magnetic nanoparticles showed excellent activity and high stability. In addition, it was revealed that this catalyst can be recycled five times without significant loss in catalytic activity.