Facile Surfactant- and Template-Free Synthesis and Luminescent Properties of One-Dimensional Lu2O3:Eu3+ Phosphors

Uniform Lu2O3:Eu3+ nanorods and nanowires have been successfully prepared through a simple solution-based hydrothermal process followed by a subsequent calcination process without using any surfactant, catalyst, or template. On the basis of X-ray diffraction, thermogravimetric analysis and differential scanning calorimetry, and Fourier transform infrared spectroscopy results, it can be assumed that the as-obtained precursors have the structure formula of Lu4O(OH)(9)(NO3), which is a new phase and has not been reported. The morphology of the precursors could be modulated from nanorods to nanowires with the increase of pH value using ammonia solution. The as-formed precursors could transform to cubic Lu2O3:Eu3+ with the same morphology and a slight shrinkage in size after an annealing process, Both the Lu2O3:Eu3+ nanorods and nanowires exhibit the strong red emission corresponding to the D-5(0)-F-7(2) transition of the Eu3+ ions under UV light excitation or low-voltage electron beam excitation.

High-density gold nanoparticles supported on a [Ru(bpy)(3)](2+)-doped silica/Fe3O4 nanocomposite: Facile preparation, magnetically induced immobilization, and applications in ECL detection

A large-scale process combined sonication with self-assembly techniques for the preparation of high-density gold nanoparticles supported on a [Ru(bpy)(3)](2+)-doped silica/Fe3O4 nanocomposite (GNRSF) is provided. The obtained hybrid nanomaterials containing Fe3O4 spheres have high saturation magnetization, which leads to their effective immobilization on the surface of an ITO electrode through simple manipulation by an external magnetic field (without the need of a special immobilization apparatus). Furthermore, this hybrid nanomaterial film exhibits a good and very stable electrochemiluminescence (ECL) behavior, which gives a linear response for tripropylamine (TPA) concentrations between 5 mu m and 0.21 mM, with a detection limit in the micromolar range. The sensitivity of this ECL sensor can be easily controlled by the amount of [Ru(bpy)(3)](2+) immobilized on the hybrid nanomaterials (that is, varying the amount of [Ru(bpy)(3)](2+) during GNRSF synthesis).

N,N,N ',N '-Tetramethylchloroformamidinium Chloride-Mediated Cyclizations of beta-Oxo Amides: Facile and Divergent One-Pot Synthesis of Substituted 2H-Pyrans, 4H-Pyrans and Pyridin-2(1H)-ones

An efficient and divergent one-pot synthesis of substituted 2H-pyrans, 4H-pyrans and pyridin-2(1H)-ones from beta-oxo amides based on the selection of the reaction conditions is reported. Mediated by N,N,N',N'-tetramethylchloroformamidinium chloride, beta-oxo amides underwent intermolecular cyclizations in the presence of triethylamine at room temperature to give substituted 2H-pyrans in high yields, which could be converted into substituted 4H-pyrans in the presence of sodium hydroxide in ethanol at room temperature, or into substituted pyridin-2(1H)-ones under reflux.

Facile synthesis of platinum nanoelectrocatalyst with urchinlike morphology

A very simple and effective wet chemical route to direct synthesis of well-dispersed Pt nanoparticles with urchinlike morphology is proposed, which was carried out by simply mixing H2PtCl6 aqueous solution and poly(vinyl pyrrolidone) with the initial molar ratios of 1:3.5 kept constant at 30 degrees C for 3 days in the presence of formic acid. As-prepared urchinlike Pt nanostructures showed excellent electrocatalytic activity toward the reduction of dioxygen and oxidation of methanol and could be used as a promising nanoelectrocatalyst.

A Facile and Efficient One-Pot Synthesis of Substituted Quinolines from alpha-Arylamino Ketones Under Vilsmeier Conditions

An efficient one-pot synthesis of substituted quinolines from alpha-arylamino ketones in the presence of PBr3 in DMF has been developed. This general protocol provides a novel and facile access to substituted quinolines by sequential Vilsmeier-Haack reaction, intramolecular cyclization and aromatization reactions of alpha-arylamino ketones. PBr3 plays a dual role in the quinoline synthesis: as a key component of the Vilsmeier reagent (PBr3/DMF) and as a reducing reagent.

Ring-Opening/Recyclization Reactions of (Dimethylamino)propenoyl-Substituted Cyclopropanes: Facile Synthesis of Halogenated Pyridin-2(1H)-ones

A facile and efficient synthesis Of Substituted pyridin-2(1H)-ones has been developed by the reaction of readily available 1-carbamoyl-]-[3-(dimethylamino)propenoyl]cyclopropanes with phosphoryl chloride or phosphorus tribromide in dichloromethane at room temperature.

A Facile and Practical One-Pot Synthesis of beta-Oxo Thioamides from beta-Oxo Amides and Isothiocyanates

A facile and practical one-pot synthesis of beta-oxo thioamides from beta-oxo amides has been developed. By treatment with isothiocyanates in ethanol in the presence of potassium carbonate, a series of beta-oxo amides was converted, under reflux, in high yields into the corresponding beta-oxo thioamides.

Carbon Nanotube/Silica Coaxial Nanocable as a Three-Dimensional Support for Loading Diverse Ultra-High-Density Metal Nanostructures: Facile Preparation and Use as Enhanced Materials for Electrochemical Devices and SERS

In this paper, we have reported a very simple strategy (combined sonication with sol-gel techniques) for synthesizing well-defined silica-coated carbon nanotube (CNT) coaxial nanocable without prior CNT functionalization. After functionalization with NH2 group, the CNT/silica coaxial nanocable has been employed as a three-dimensional support for loading ultra-high-density metal or hybrid nanoparticles (NPs) such as gold NPs, Au/Pt hybrid NPs, Pt hollow NPs, and Au/Ag core/shell NPs. Most importantly, it is found that the ultra-high-density Au/Pt NPs supported on coaxial nanocables (UASCN) could be used as enhanced materials for constructing electrochemical devices with high performance. Four model probe molecules (O-2, CH3OH, H2O2, and NH2NH2) have been investigated on UASCN-modified glassy carbon electrode (GCE). It was observed that the present UASCN exhibited high electrocatalytic activity toward diverse molecules and was a promising electrocatalyst for constructing electrochemical devices with high performance. For instance, the detection limit for H2O2 with a signal-to-noise ratio of 3 was found to be 0.3 mu M, which was lower than certain enzyme-based biosensors.

Facile coprecipitation to synthesize water-soluble amine-capped magnetite nanoparticles

Water solubility and surface functionalization of magnetic nanoparticles are crucial for bioapplication.[1]In this study,we presented a facile coprecipitation approach to synthesize lysine stabilized Fe3O4 nanoparticles.Lysine functionalized magnetite nanoparticles show an excellent colloidal stability of ＞20h.The as-synthesized magnetite nanoparticles have abundant amine groups on their surface which provide convenient sites for covalent linking of biological macromolecules.We believe that these amine-functionalized magnetic nanoparticles can be potentially used in fields such as magnetic bio-separation,immunoassay,MRI,and targeted drug delivery.

A facile synthesis and characterization of monodisperse spherical pigment particles with a core/shell structnre

In this paper, a facile sol-gel process for producing monodisperse, spherical, and nonaggregated pigment particles with a core/shell structure is reported. Spherical silica particles (245 and 385 nm in diameter) and Cr2O3, alpha-Fe2O3, ZnCo2O4, CuFeCrO4, MgFe2O4, and CoAl2O4 pigments are selected as cores and shells, respectively. The obtained core/shell-structured pigment samples, denoted as SiO2@Cr2O3 (green), SiO2@alpha-Fe2O3 (red), SiO2@MgFe2O4 (brown), SiO2@ZnCo2O4 (dark green), SiO2@CoAl2O4 (blue), and SiO2@CuFeCrO4 (black), are well characterized by using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), and UV-vis diffuse reflection, as well as by investigating the magnetic properties. The results of XRD and high-resolution TEM (HRTEM) demonstrate that the pigment shells crystallize well on the surface Of SiO2 Particles. The thickness of the pigment shell can be tuned by the number of coatings, to some extent. These pigment particles can be well dispersed in some solvents (such as glycol) to form relatively more stable suspensions than the commercial products.

Soluble neodymium chloride 2-ethylhexanol complex as a highly active catalyst for controlled isoprene polymerization

Soluble NdCl3 center dot 3EHOH (2-ethyl hexanol) in hexane combined with AlEt3 is highly active for isoprene polymerization in hexane. The NdCl3 center dot 3EHOH/AlEt3 has higher activity than the typical binary catalyst NdCl3 center dot 3(i)PrOH (isopropanol)/AlEt3 and ternary catalyst NdV3 (neodymium versatate)/AlEt2Cl/Al(i-Bu)(2)H. The molecular weight of polyisoprenes can be controlled by variation of [Nd], [Al]/[Nd] ratio and polymerization temperature and time. The NdCl3 center dot 3EHOH/AlEt3 catalyst polymerized isoprene to afford products featuring high cis-1,4 stereospecificity (ca. 96%), high molecular weight (ca. 10(5)) and relatively narr ow molecular weight distributions (M-w/M-n = 2.0-2.8) simultaneously. More importantly, some living polymerization characteristics were demonstrated: (a) absence of chain termination; (b) linear correlation between M-n and polymer yield; (c) increment of molecular weight in the 'seeding' polymerization. Though some deviation from the typical living polymerization such as molecular weight distribution is not narrow enough and the line of M-n and polymer yield does not extrapolate to zero, controlled polymerization with the current catalyst can still be concluded.

Polymerization of 1,3-butadiene with VO(P-204)(2) and VO(P-507)(2) activated by alkylaluminum

The oxovanadium phosphonates (VO(P-204)(2) and VO(P-507)(2)) activated by various alkylaluminums (AlR3, R = Et, i-Bu, n-Oct; HAIR(2), R = Et, i-Bu) were examined in butadiene (Bd) polymerization. Both VO(P-204)(2) and VO(P-507)(2) showed higher activity than those of classical vanadium-based catalysts (e.g. VOCl3, V(acac)(3)). Among the examined catalysts, the VO(P-204)(2)/Al(Oct)(3) system (I) revealed the highest catalytic activity, giving the poly(Bd) bearing M-n of 3.76 x 10(4) g/mol, and M-w/M-n ratio of 2.9, when the [Al]/[V] molar ratio was 4.0 at 40 degrees C. The polymerization rate for I is of the first order with respect to the concentration of monomer. High thermal stability of I was found, since a fairly good catalytic activity was achieved even at 70 degrees C (polymer yield > 33%); the M-n value and M-w/M-n, ratio were independent of polymerization temperature in the range of 40-70 degrees C. By IR and DSC, the poly(Bd)s obtained had high 1,2-unit content (> 65%) with atactic configuration. The 1,2-unit content of the polymers obtained by I was nearly unchanged, regardless of variation of reaction conditions, i.e. [Al]/[V], ageing time, and reaction temperature, indicating the high stability of stereospecificity of the active sites.

Influence of montmorillonite on syndiotactic polymerization behavior of styrene

The influence of montmorillonite (MMT) on the syndiotactic polymerization behavior of styrene was studied. To avoid the hydrophilic surface of the MMT coming into contact with the catalyst, which could poison it, SAN was introduced between the MMT and Cp*Ti (OCH3)(3). MMT was introduced into the catalytic system as a supporter for the Ti catalyst (supported catalytic system) or just dispersed in the polymerization solvent directly (in situ polymerization system). The polymerization results showed that surface modification of MMT dramatically affected the catalytic activity as well as the syndiotacticity of the polymers. This is mainly explained by the insulator SAN preventing the formation of the inactive/little active species Si-O-Ti and other atactic active species resulting from the reaction of the -OH on the MMT layer surface with Cp*Ti(OCH3)(3).

Analysis of chemical calorific effect during reactive extrusion processes for free radical polymerization

In the reactive extrusion process for polymerization, the chemical calorific effect has a great influence on the temperature. In order to quantitatively analyze the polymerization trend and optimize the processing conditions, the phenomena of the chemical calorific effect during reactive extrusion processes for free radical polymerization were analyzed. Numerical computation expressions of the heat of chemical reaction and the reactive calorific intensity were deduced, and then a numerical simulation of the reactive extrusion process for the polymerization of n-butyl methacrylate was carried out. The evolutions of the heat of chemical reaction and the reactive calorific intensity along the! axial direction of the extruder are presented, on the basis of which reactive processing conditions can be optimized.