共查询到20条相似文献,搜索用时 46 毫秒
1.
Cousinié S Gressier M Reber C Dexpert-Ghys J Menu MJ 《Langmuir : the ACS journal of surfaces and colloids》2008,24(12):6208-6214
This work focuses on the grafting of transition metal complexes on silica surface nanoparticles. Nanoscale silica particles in aqueous sols are used as starting silicated materials. We have undertaken the synthesis of europium(III) complexes containing organosilyldipyridine ligands, (EtO)3Si(CH2)3NHCH2-bipy (1) and (EtO)(CH3)2Si(CH2) 3NHCH 2-bipy (2), in view of a direct grafting reaction on silica nanoparticles. Reaction of one molar equivalent of 1 and 2 with Eu(tmhd)3 (tmhd= 2,2,6,6-tetramethyl-3,5-heptanedionato), as precursor, leads to octacoordinated silylated europium(III) complexes [Eu(tmhd)3(1)] (3) and [Eu(tmhd)3(2)] (4) as white solids in 34-54% yields. Europium complexes were characterized by elemental analysis, mass spectrometry, FT-IR, UV, and luminescence spectroscopies. These new complexes are reacting in a 1:10 (v/v) water and ethanol mixture with silica nanoparticles colloidal sol. Elemental analysis and thermogravimetric data indicated grafting ratios of 0.41 and 0.26 mmol of europium(III) complexes per gram of silica. Functionalized silica nanoparticles were characterized by DRIFT spectroscopy and TEM microscopy. The first analysis shows that the chemical integrity of the complexes is retained on the silica surface together with the size and the monodispersity of the nanoscale particles. As expected for europium(III) complexes, luminescence is observed under UV irradiation. Emission and excitation spectra indicate that the metal coordination environment is not modified on the silica surface. Moreover, the sharpness of the luminescence bands and the strong antenna effect are maintained when complexes are covalently bonded to silica. New luminescent europium(III) complexes grafted on silica nanoparticles are therefore obtained from our approach. 相似文献
2.
Fei Gao Ye Sheng Yanhua Song Keyan Zheng Chunming Lin Hui Zhang Qisheng Huo Haifeng Zou 《Journal of Sol-Gel Science and Technology》2014,71(2):313-323
Photoluminescent nanomaterials had emerged as an amazing field in a wide range of applications during the past few decades. In this article, fibrous europium tartrates and photoluminescent silica nanotubes were conveniently synthesized by using sol–gel method, in which europium ions entered silica matrix. Scanning electron microscopy, transmission electron microscopy, X-ray diffraction analysis, fourier transform infrared spectra, energy-dispersive X-ray spectroscopy and photoluminescence (PL) spectra analysis were used to characterize the growth, structure, morphology and optical property of the products. The results indicated that europium tartrates nanofibers as a template can transform tetraethylorthosilicate into silica nanotubes effectively. Meanwhile, europium(III) was transferred from the fibers to the tubes successfully. A hard template mechanism was proposed to explain the formation process of europium(III)-doped silica nanotubes. Moreover, different morphologies of silica-based nanomaterials were obtained due to varying NH4OH addition or stirring time. PL spectra from nanofiber and nanotube show a typical emission of europium(III), and 13 % is the quenching concentration of europium(III) in silica matrix for this system. The novel silica nanotubes can be applied potentially in optical and biological areas. 相似文献
3.
Features of a sorption-luminescence method for the determination of trace europium were studied. The method includes the preliminary
sorption of europium at pH 7.1 from solutions with silica chemically modified with iminodiacetic acid, the subsequent treatment
of the sorbent with 2-thenoyltrifluoroacetone at pH 8.0, and the measurement of the intensity of luminescence of the surface
three-component europium complex at 613 nm. The effect of moisture as the quencher of luminescence of the surface europium
complex was studied, and techniques for its removal were proposed. Sorption in the static mode provides the detection limit
of europium of 7 × 10−5 μg/mL. The calibration plot is linear in the range of two orders of magnitude of europium concentration in solutions. The
relative standard deviation in the determination of 1.5 × 10−2 μg/mL europium is 5%. In the dynamic mode of sorption from 1000 mL of an analyzed solution with the use of sorption-desorption,
the detection limit of europium of 8 × 10−7 μg/mL was attained.
Original Russian Text ? R.D. Voronina, N.B. Zorov, 2007, published in Zhurnal Analiticheskoi Khimii, 2007, Vol. 62, No. 3,
pp. 230–237. 相似文献
4.
I. V. Kalinovskaya V. G. Kuryavyi A. N. Zadorozhnaya V. A. Karasev 《Russian Journal of General Chemistry》2006,76(7):1015-1018
The luminescence characteristics of heteroligand europium cinnamates are reported. As follows from the IR spectra, cinnamic acid coordinates with europium in these compounds in the bidentate fashion. The shape, size, and surface morphology of particles of heteroligand europium cinnamates were determined by scanning electron and atomic force microscopy. Heteroligand europium complexes usually form plate-like and needle-like microcrystals of size 0.1–15 μm. 相似文献
5.
A. R. Bikmullina A. A. Tereshchenkova M. A. Statkus T. I. Tikhomirova 《Moscow University Chemistry Bulletin》2013,68(4):186-190
The sorption of a complex of europium (III) with acetylacetone on silica gel chemically modified with hexadecyl groups (SiO2-C16) and hyper crosslinked polystyrene (HLPS) was studied. Maximum extraction was observed at pH 5–7 when SiO2-C16 was used as the sorbent and at pH 4–7 in the case of crosslinked polystyrene. The partition coefficients for HLPS and silica gel were calculated as 7 × 103 and 1 × 102 cm3/g, respectively. Quantitative extraction of the europium (III) complex was possible in dynamic conditions using a microcolumn (length, 10 mm; internal diameter, 3mm) packed with HLPS at pH 5 (10–50 mL sample volume). Desorption of europium using solutions of nitric acid at different concentrations was investigated. Quantitative desorption was achieved using 5 mL of 1 M HNO3. A linear range of detection was observed at an amount of europium from 5 to 25 μg in a 10-mL sample (650 nm). 相似文献
6.
Tomokatsu Hayakawa S. Tamil Selvan Masayuki Nogami 《Journal of Sol-Gel Science and Technology》2000,19(1-3):779-783
We have investigated the energetic correlation between rare-earth ions and semiconductor nanocrystals, using europium ion (Eu3+) doped silica (SiO2) gel with adsorbed cadmium sulfide (CdS) particles. Samples were prepared by a sol-gel technique, in which several methods for the precipitation of CdS colloids were attempted. The fluorescence intensities were compared for different gels, with and without CdS particles. The intrinsic emission lines due to 5D0 7FJ(J = 0–4) transitions of Eu3+ were observed, which were enhanced for 24 h-immersed gel (dried at 50°C). From the results on the decay dynamics of fluorescence, we proposed the model that surface-trapped electrons on CdS particles nonradiatively excited 4f electrons in Eu3+ ions due to an energy transfer process. 相似文献
7.
Dong-ming Qi Yong-zhong Bao Zhi-ming Huang Zhi-xue Weng 《Colloid and polymer science》2008,286(2):233-241
Polyacrylate/silica nanocomposite latex particles were prepared by in situ emulsion polymerization of acrylate monomers initiated
by 2,2′-azobis(2-amidinopropane)dihydrochloride (AIBA) adsorbed by silica nanoparticles. The anchoring of polyacrylate (ACR)
onto silica nanoparticles was achieved through the physical absorption and chemical grafting reaction. The elution and HF
etching experiments showed that most silica nanoparticles were encapsulated by ACR to form the raspberry-like ACR/silica nanocomposite
latex particles. The silica nanoparticles with a greater grafting degree of ACR tended to locate in the bulk of the polymer,
and the silica particle with a lower grafting degree would not be combined with polymer latex particles and always remained
in water phase. The formation of the final ACR/silica nanocomposite latex particles included the anchoring of ACR onto silica
primary particles, aggregation of silica primary particles to form the silica-containing latex particles, and the growth of
latex particles. 相似文献
8.
I. V. Kalinovskaya V. E. Karasev Yu. M. Nikolenko V. G. Kuryavyi 《Russian Journal of Physical Chemistry A, Focus on Chemistry》2006,80(9):1389-1391
The reactions that occur during the mechanochemical treatment of europium nitrate with 1,10-phenanthroline were studied by X-ray electron, infrared, and luminescent spectroscopy. Two minutes of mechanical activation resulted in the formation of europium nitrate, 1,10-phenanthroline, and water. According to the X-ray electron spectroscopy data, the coordination of 1,10-phenanthroline to europium nitrate was accompanied by a decrease in the Eu 4d 5/2 binding energy. Intense mechanochemical transformations caused changes in the composition of the surface of samples. Changes in the shape and size of reaction mixture particles and the morphology of sample surfaces after mechanical treatment in a ball mill compared with the initial mixture were studied. 相似文献
9.
The spectroscopic properties of europium in aluminium codoped silica glasses produced by the sol-gel technique have been studied with respect to the dopant concentrations and the thermal processing applied to the samples. After thermal annealing at temperatures up to 950_°C the bright red fluorescence around 613 nm characteristic for the trivalent europium ions (Eu3 +) has been observed. The lifetime was measured to be 0.1–2.4 ms depending on dopant concentrations and thermal treatment. Subsequent CO2-laser processing in air (short time remelting) gave rise to a bright blue fluorescence consisting of two broad bands, lying around 450 and 490 nm, with their peak position depending on the ratio between the aluminium and europium concentrations. The fluorescence lifetimes were found to be shorter than 1 s. This blue fluorescence is attributed to the divalent europium ion (Eu2 +), leading to the conclusion that the CO2-laser processing of europium doped alumina-silica glasses resulted in the reduction of the trivalent to the divalent europium ion. Laser processing could therefore be a valid alternative to conventional thermal annealing for the generation of Eu2 + in alumina-silica glasses. 相似文献
10.
S. N. Ivicheva Yu F. Kargin N. A. Aladiev S. V. Kutsev V. S. Gorelik 《Journal of Sol-Gel Science and Technology》2013,68(3):429-437
Ordered 3D composites based on opal matrices and silica sols doped with rare earth elements have been prepared using colloidal chemistry methods. A uniform distribution of rare earth elements (which is important for avoiding luminescence concentration quenching) was achieved by means of repeated filling of the opal matrix interstitial space with silica sols doped with salts or oxides of rare earth elements. Trace amounts (10–30 ppm) of europium in a composite were shown to strongly affect optical properties of the material. 相似文献
11.
O. V. Davydova N. E. Drobyshevskaya E. N. Poddenezhnyi A. A. Boiko A. V. Zdravkov N. N. Khimich 《Russian Journal of Applied Chemistry》2016,89(10):1601-1606
Powders were synthesized in the yttrium oxide + zinc oxide system doped with europium oxide by the method of redox combustion of a mixture of yttrium, zinc, and europium nitrates in the presence of saccharose (fuel). The structure and the physicochemical and luminescent properties of the particles being formed and of a ceramic on their basis were examined. 相似文献
12.
Kwang-Pill Lee Sun-Tae Hwang Y. Yamada K. Furukawa Shin-Ichi Ohno 《Journal of Radioanalytical and Nuclear Chemistry》1992,160(1):203-209
Impact of energetic heavy particles on europium compound surfaces gives rise to radiative optical emission from reflected and sputtered particles and from the excited states of the solid compounds. In the present paper we discuss the optical spectrum and the sputtered secondary ion mass spectrum observed when solid europium oxide (Eu2O3) and europium chloride (EuCl3) are bombarded with 90 keV Ar+ ions from an ion accelerator. We observe the reduction reaction in solid europium chloride (EuCl3) by bombardment with a 20 A/cm2 beam of 90 keV Ar+ ions. 相似文献
13.
14.
Nano-sized metal particles, including both elemental and oxidized metals, have received significant interest due to their biotoxicity and presence in a wide range of industrial systems. A novel silica technology has been recently explored to minimize the biotoxicity of metal particles by encapsulating them with an amorphous silica shell. In this study, a method to determine silica coating efficiency on metal particles was developed. Metal particles with silica coating were generated using gas metal arc welding (GMAW) process with a silica precursor tetramethylsilane (TMS) added to the shielding gas. Microwave digestion and Inductively Coupled Plasma-Atomic Emission Spectroscopy (ICP-AES) were employed to solubilize the metal content in the particles and analyze the concentration, respectively. Three acid mixtures were tested to acquire the appropriate digestion method targeting at metals and silica coating. Metal recovery efficiencies of different digestion methods were compared through analysis of spiked samples. HNO3/HF mixture was found to be a more aggressive digestion method for metal particles with silica coating. Aqua regia was able to effectively dissolve metal particles not trapped in the silica shell. Silica coating efficiencies were thus calculated based on the measured concentrations following digestion by HNO3/HF mixture and aqua regia. The results showed 14-39% of welding fume particles were encapsulated in silica coating under various conditions. This newly developed method could also be used to examine the silica coverage on particles of silica shell/metal core structure in other nanotechnology areas. 相似文献
15.
Polystyrene‐core–silica‐shell hybrid particles were synthesized by combining the self‐assembly of nanoparticles and the polymer with a silica coating strategy. The core–shell hybrid particles are composed of gold‐nanoparticle‐decorated polystyrene (PS‐AuNP) colloids as the core and silica particles as the shell. PS‐AuNP colloids were generated by the self‐assembly of the PS‐grafted AuNPs. The silica coating improved the thermal stability and dispersibility of the AuNPs. By removing the “free” PS of the core, hollow particles with a hydrophobic cage having a AuNP corona and an inert silica shell were obtained. Also, Fe3O4 nanoparticles were encapsulated in the core, which resulted in magnetic core–shell hybrid particles by the same strategy. These particles have potential applications in biomolecular separation and high‐temperature catalysis and as nanoreactors. 相似文献
16.
Hasegawa Koichi Kunugi Shunsuke Tatsumisago Masahiro Minami Tsutomu 《Journal of Sol-Gel Science and Technology》1999,15(3):243-249
Thick films were prepared by the electrophoretic sol-gel deposition of organically modified, sub-micron silica particles. The silica particles were modified with 3-aminopropyltriethoxysilane (APS) and vinyltriethoxysilane (VTES). Smooth and crack-free films ca. 15 m thick were obtained when APS modified silica particles were used for the cathodic electrophoretic deposition. Thick films with decreased open spaces among particles were obtained when silica particles modified with VTES were co-deposited with an organic polymer, polyethylene maleate. 相似文献
17.
Y. Kobayashi S. Saeki M. Yoshida D. Nagao M. Konno 《Journal of Sol-Gel Science and Technology》2008,45(1):35-41
This paper describes a method for fabricating spherical submicron-sized silica particles that contained magnetite nanoparticles
(magnetite/silica composite particles). The magnetite nanoparticles with a size of ca. 10 nm were prepared according to the Massart method, and were surface-modified with carboxyethylsilanetriol. The fabrication
of magnetite/silica composite particles was performed in water/ethanol solution of tetraethoxyorthosilicate with ammonia catalyst
in the presence of the surface-modified magnetite nanoparticles. The magnetite/silica composite particles with a size of ca. 100 nm were successfully prepared at 0.05 M TEOS, 15 M water, and 0.8 M ammonia with injection of the magnetite nanoparticle
colloid at 2 min after the initiation of hydrolysis reaction of TEOS. Magnetite concentration in the composite particles could
be raised to 17.3 wt.% by adjustment of the injected amount of the magnetite colloid, which brought about the saturation magnetization
of 7.5 emu/g for the magnetite/silica composite particles. 相似文献
18.
杂化硅胶整体材料研磨法制备混合型高效液相色谱固定相 总被引:1,自引:0,他引:1
以聚乙二醇(PEG)为致孔剂,四甲氧基硅烷(TMOS)和乙烯基三甲氧基硅烷(VTMS)为杂化硅胶前驱体,在乙酸催化作用下使硅烷发生水解,在尿素加热分解提供的碱性环境下水解的硅烷进一步缩聚得到杂化硅胶整体材料。将此整体材料用球磨机研磨,然后用三羟甲基氨基甲烷处理,并洗涤干燥得到粒径为3 μm左右的硅胶颗粒。探索了不同反应条件对硅胶颗粒的大小、比表面积和孔径、表面形貌和分散性的影响;当TMOS和VTMS体积比为3:1时可以得到孔径为7.5 nm和比表面积为245 m2/g的硅胶颗粒。通过对所制得的硅胶颗粒表面进行C18(十八烷基二甲基氯硅烷)键合修饰和巯基-烯点击反应,得到混合型高效液相色谱固定相。对此固定相的测试结果表明以上硅胶色谱填料的制备方法具有一定的实用性。 相似文献
19.
Pickering乳液模板法制备Janus粒子 总被引:4,自引:0,他引:4
本文以SiO2粒子稳定的水包油(O/W)型Pickering乳液作为模板, 在乳液连续相进行SI-ATRP, 将聚合物刷接枝到SiO2粒子外半表面, 破乳得到半修饰的Janus粒子. 相似文献