首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
The article referenced above was first published online on 7 August 2007 with incorrect pagination; the pagination has now been corrected online and in print. Copyright © 2007 John Wiley & Sons, Ltd.  相似文献   

2.
《Mendeleev Communications》2021,31(5):718-720
This communication describes a new method for immobilizing indium oxide nanoparticles (∼20 nm) on the surface of reduced graphene oxide. Dispersion of graphene oxide with added In2O3 nanoparticles was treated in supercritical isopropanol, both a reducing agent of graphene oxide and a reaction medium. The resulting nanocomposite was characterized by different methods of physical and chemical analysis.  相似文献   

3.
Propene, one of key building blocks for manufacturing plastics and chemicals, could be directly and stably produced from ethanol in good yields. The conversion degree of ethanol to propene reached approximately 60 mol % by using a 3 atom % scandium‐loaded indium oxide catalyst at 823 K in the presence of water and hydrogen. The introduction of Sc prevented the reduction of In2O3 to In metal during the reaction, and that of water decreased the coke formation. Both additions resulted in longer lifetimes of the catalysts. The hydrogen addition increased the conversion of acetone to propene. The reaction pathways are also suggested on the basis of the product distributions and the pulse experiments, ethanol→acetaldehyde→acetone→propene, which is quite different from the shape‐selective catalysis on zeolites and the dimerization‐metathesis of ethene on nickel ion‐loaded silica catalysts.  相似文献   

4.
The crystal structures of the ordinary pressure forms of indium digermanate In2Ge2O7 and disilicate In2Si2O7 have been studied from X-ray powder diffraction data by Rietveld refinement. They are closely related to that of the thortveitite which crystallizes in the monoclinic system with the space group C2/m and Z = 2. They show luminescence properties below 160 K and 200 K respectively. The luminescence is discussed in terms of crystal structure and compared to that of some other luminescent indium oxides.  相似文献   

5.
This study presents the synthesis and characterization of zwitterionic core–shell hybrid nanoparticles consisting of a core of iron oxide multicore nanoparticles (MCNPs, γ‐Fe2O3) and a shell of sultonated poly(2‐vinylpyridine‐grad‐acrylic acid) copolymers. The gradient copolymers are prepared by reversible addition fragmentation chain transfer polymerization of 2‐vinylpyridine (2VP), followed by the addition of tert‐butyl acrylate and subsequent hydrolysis. Grafting of P(2VP‐grad‐AA) onto MCNP results in P(2VP‐grad‐AA)@MCNP, followed by quaternization using 1,3‐propanesultone—leading to P(2VPSgrad‐AA)@MCNP with a zwitterionic shell. The resulting particles are characterized by transmission electron microscopy, dynamic light scattering, and thermogravimetric analysis measurements, showing particle diameters of ≈70–90 nm and an overall content of the copolymer shell of ≈10%. Turbidity measurements indicate increased stability toward secondary aggregation after coating if compared to the pristine MCNP and additional cytotoxicity tests do not reveal any significant influence on cell viability.

  相似文献   


6.
7.
Water‐dispersible and luminescent gadolinium oxide (GO) nanoparticles (NPs) were designed and synthesized for potential dual‐modal biological imaging. They were obtained by capping gadolinium oxide nanoparticles with a fluorescent glycol‐based conjugated carboxylate (H L ). The obtained nanoparticles (GO‐ L ) show long‐term colloidal stability and intense blue fluorescence. In addition, L can sensitize the luminescence of europium(III) through the so‐called antenna effect. Thus, to extend the spectral ranges of emission, europium was introduced into L‐ modified gadolinium oxide nanoparticles. The obtained EuIII‐doped particles (Eu:GO‐ L ) can provide visible red emission, which is more intensive than that without L capping. The average diameter of the monodisperse modified oxide cores is about 4 nm. The average hydrodynamic diameter of the L ‐modified nanoparticles was estimated to be about 13 nm. The nanoparticles show effective longitudinal water proton relaxivity. The relaxivity values obtained for GO‐ L and Eu:GO‐ L were r1=6.4 and 6.3 s?1 mM ?1 with r2/r1 ratios close to unity at 1.4 T. Longitudinal proton relaxivities of these nanoparticles are higher than those of positive contrast agents based on gadolinium complexes such as Gd‐DOTA, which are commonly used for clinical magnetic resonance imaging. Moreover, these particles are suitable for cellular imaging and show good biocompatibility.  相似文献   

8.
以In(NO_3)_3·4.5H_2O和(NH_2)_2CO为原料,采用常压水热法于95℃反应22 h制得氧化铟(In_2O_3)前驱物氢氧化铟,于600℃煅烧2 h合成了In_2O_3粉体,其结构、形貌及性能经紫外-可见(UV-Vis)光谱、X-射线衍射(XRD)、拉曼光谱和扫描电镜(SEM)表征。以甲基橙为目标降解物,研究了In_2O_3粉体的光催化活性。结果表明:In_2O_3粉体为体心立方晶系方铁锰矿结构和亚稳相刚玉六方结构的混合体,In_2O_3的UV-Vis谱图中出现了明显的蓝移。当In(NO_3)_3·4.5H_2O和(NH_2)_2CO物质的量比为1∶7时,In_2O_3粉体中出现了玉米棒状结构,棒状体长度约为500 nm,直径约150 nm;该棒状结构的In_2O_3对甲基橙有较好的光催化活性,在紫外光照射6.5 h后甲基橙的降解率为69.7%。  相似文献   

9.
Soluble conjugated polymeric nanoparticles were synthesized through Sonogashira polycondensation between different combinations of multifunctional alkynes and aryl halides in structurally well‐defined mesoporous reactors. The growth of the polymeric nanoparticles was controlled by the spatial confinement of the nanoreactors, giving conjugated polymeric nanoparticles with narrow size distribution centered at 5 nm. All the obtained polymers are freely soluble in common solvents and can be fabricated into thin film. Both of the solution and thin film prepared from these polymeric nanoparticles were highly fluorescent, endowing them potential applications in light emitting and other optoelectronic fields. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 2285–2290  相似文献   

10.
本文利用系列有机二元酸-水体系作为制备In(OH)3纳米晶体介质,采用低温水热法成功制备了不同形貌和尺寸的In(OH)3为纳材料。利用扫描电镜(SEM)、透射电镜(TEM)、X-射线衍射(XRD)、傅立叶红外光谱仪(FT-IR)和拉曼光谱仪(Raman)等手段分别对材料的形貌、结构和物相等进行了表征与分析。实验结果表明,通过本研究方法,在己二酸水体系中可以得到较均一的尺寸在300-400 nm范围的In(OH)3球形粒子,而在癸二酸水体系中则得到棒状和片状混杂的In(OH)3纳米颗粒。样品在450°C条件下焙烧4 h后,可获得相应的具有良好形貌继承性的In2O3微纳材料。  相似文献   

11.
A simple and versatile synthetic methodology to silver metal nanoparticles that utilizes 3,5‐dihydroxybenzyl alcohol‐based dendrimers as templates and does not necessitate the addition of any external reducing agent is reported. An evaluation of the role of addition rate of the silver acetate solution, and the dendrimer to silver acetate molar ratio, as well as the dendritic effect on nanoparticle growth, suggests that the size of these metal nanoparticles can be controlled by simple variations of these parameters. A probe of the mechanism of the nanoparticle formation and growth indicates that the terminal hydroxyl groups of the dendrimers play a major role in metal ion isolation and reduction, in addition to providing stabilization to the growing metal particles. These silver metal nanoparticles are highly active catalysts for the selective reduction of chloronitrobenzenes to chloroanilines. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4482–4493, 2009  相似文献   

12.
On the Crystal Structure of Ba3In2Zn5O11. An Oxoindate/zincatesol;zincate with Zn10O20 and In4O16 Macropolyhedra with Zn2+ in Tetrahedral Coordination by O2? Ba3In2Zn5O11 was prepared for the first time by a flux technique and investigated by single crystal X-ray work. It crystallizes with cubic symmetry, space group T-F4 3m, a = 13.3588 Å, Z = 8. Zn2+ show tetrahedral coordination by O2?, forming Zn10O20 macropolyhedra. In addition the nZn/Osol;O part of the crystal structure is made up of Zn10O20 parts. Edge connection of four InO6 octahedra results in In4O16 groups. The crystal structure will be shown and discussed.  相似文献   

13.
A novel t hiourea dioxide‐functionalized hydroxyapatite‐encapsulated hybrid core‐shell γ‐Fe2O3@HAp‐TUD nanoparticles (MNPs) were prepared and characterized by FT‐IR, EDX, SEM, XRD, TGA and VSM analytical methods. The catalytic activity of these MNPs was evaluated through one‐pot three‐component reactions between various substituted aldehydes, malononitrile and 3‐cyano‐6‐hydroxy‐4‐methyl‐pyridin‐2(1H )‐one to afford the corresponding pyrano[2,3‐b]pyridines in high yields under mild and solvent‐free conditions. The catalyst can be easily recycled in a magnetic field and reused in five consecutive runs without significant decrease of its catalytic activity.  相似文献   

14.
以2-巯基-5-(3,4,5-三甲氧基苯基)-1,3,4-噻二唑为原料,经醚化、酰肼化、闭环、硫醚化四步反应合成了10个2-(3,4,5-三甲氧基苯基)-5-[(5-烷硫基-1,3,4-噁二唑-2-基)硫甲基]- 1,3,4-噻二唑类衍生物。通过元素分析、IR、MS、1H NMR和 13C NMR对目标化合物进行了表征。采用In(OTf)3催化下40 oC水相合成目标化合物,具有反应条件温和、合成收率高、催化剂可循环使用等特点。  相似文献   

15.
A three‐dimensional reduced graphene oxide aerogel with embedded nickel oxide nanoparticles was prepared by a one‐step self‐assembly reaction in a short time. The nanoparticles could be captured into the interior of reduced graphene oxide network during the formation of the three‐dimensional architecture. The composite exhibited porosity, good biocompatibility, and abundant metal affinity binding sites. The aerogel was used to isolate ovalbumin selectively from egg white, and favorable adsorption was achieved at pH 3. An adsorption efficiency of 90.6% was obtained by using 1 mg of the composite for adsorbing 70 μg/mL of ovalbumin in 1.0 mL of sample solution, and afterwards a recovery of 90.7% was achieved by using an eluent of 1.0 mL Britton–Robinson buffer solution at pH 5. After the adsorption/desorption, ovalbumin showed no change in the conformation. The adsorption behavior of ovalbumin on the reduced graphene oxide composite well fitted to the Langmuir adsorption model, and a corresponding theoretical maximum adsorption capacity was 1695.2 mg/g. A sodium dodecyl sulfate polyacrylamide gel electrophoresis assay demonstrated that the aerogel could selectively isolate ovalbumin from chicken egg white.  相似文献   

16.
A series of random copolymers with different beta-cyclodextrin contents were synthesized by radical copolymerization of MMA with a monovinyl beta-CD monomer. The copolymers were characterized with IR spectroscopy, elemental analysis, DSC, and TGA. Based on these copolymers, their nanoparticles were prepared by using DMF, water, and acetone as solvents. Aqueous dispersions of the nanoparticles were further obtained by dialysis against water. Zetasizer Nano-ZS dynamic light scattering and transmission electron microscopy were employed to characterize the nanoparticles. Using camptothecin as a model drug molecule, the encapsulation efficiency and release behavior of the nanoparticles were investigated.  相似文献   

17.
In this work, a new synthetic route for the preparation of ZnFe2O4 nanoparticles through the chemical co‐precipitation using Fe2+ and Fe3+ ions in an alkaline solution was developed. The synthesized nanoparticles were characterized by XRD, FTIR, SEM, ICP‐MS, DRS, TGA, VSM and elemental analysis. Characterization results confirmed the formation of single ZnFe2O4 phase, with an average particle size of 40 nm and a high saturation magnetization of 34 emu g?1. The prepared material was employed as a catalyst for the synthesis of 2‐aminotiophene derivatives through the Gewald reaction. This thermally and chemically stable nanocatalyst is environmentally benign, economical and reusable which can be easily recovered using an external magnet. Therefore, it appears that this methodology can be simply extended for industrial purposes.  相似文献   

18.
One‐pot dual size‐ and shape‐selective synthesis of tetrahedral Pt nanoparticles is achieved using the pre‐prepared Pt nanoparticles as the ‘external seeds’, and controlling the slow diffusional growth under hydrogen reduction in the presence of PVP as the capping agent. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   

19.
《中国化学》2017,35(7):1125-1132
A novel biocompatible polymer was prepared by grafting the derivate of β ‐cyclodextrin (6‐SH ‐β ‐CD ) onto poly(3,4‐dihydroxycinnamic acid) (PDHCA ) via Michael addition. PDHCA ‐β ‐CD nanoparticles were prepared by the self‐assembly of amphiphilic PDHCA ‐β ‐CD polymer with N,N ‐dimethylformamide (DMF ) as good solvent and water as poor solvent. The PDHCA ‐β ‐CD nanoparticles were monodispersed with spherical morphology as shown in the scanning electron microscopic (SEM ) images in accord with the result of dynamic light scattering (DLS ) measurement. The size of the nanoparticles could be controlled from 60 to 180 nm by tuning the grafting degree (GD ) of PDHCA ‐β ‐CD polymer and also significantly influenced by the amount of water used during the process. These as‐prepared nanoparticles were stable without any significant change in the particle size after six‐months’ storage and even after being irradiated by UV at λ >280 nm for hours. The formation mechanism of PDHCA ‐β ‐CD nanoparticles was explored. The content of doxorubicin (DOX ) loaded onto the nanoparticles was up to 39% with relatively high loading efficiency (approximately 78.8% of initial DOX introduced was loaded). In vitro release studies suggested that DOX released slowly from PDHCA ‐β ‐CD nanoparticles. These features strongly support the potential of developing PDHCA ‐β ‐CD nanoparticles as carriers for the controlled delivery of drug.  相似文献   

20.
Multifunctional polymer unimolecular micelles, which are used as templates to fabricate stable gold nanoparticles (GNPs) in one‐step without external reductant, have been designed and prepared. Amphiphilic 21‐arm star‐like block copolymers β‐cyclodextrin‐{poly(lactide)‐poly(2‐(dimethylamino) ethyl methacrylate)‐poly[oligo(2‐ethyl‐2‐oxazoline)methacrylate]}21 [β‐CD‐(PLA‐PDMAEMA‐PEtOxMA)21] and the precursors are synthesized by the combination of ring‐opening polymerization (ROP) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). The tertiary amine groups of PDMAEMA block reduce the counterion to zerovalent gold in situ, and these gold atoms combine mutually to form final GNPs. GNPs with relatively small size and narrow size distribution can be obtained in longer DMAEMA block copolymer, larger molar ratio of DMAEMA to HAuCl4 and smaller absolute concentrations of both polymer and HAuCl4. These results showed that the unimolecular micelles can be used as templates for preparing and stabilizing GNPs in situ without any external reducing agents and organic solvents, suggesting that the nanocomposite systems are latent nanocarriers for further biomedical application. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 186–196  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号