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1.
Two novel ternary rare earth complexes LnL5L′(ClO4)32H2O (Ln=Eu(III), Tb(III); L=bis(benzoylmethyl) sulfoxide, L′=phen) were synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG-DSC,1H NMR and UV spectra. The fluorescence spectra illustrated that both the Eu(III) and Tb(III) ternary complexes displayed strong characteristic metal-centered fluorescence in solid state. After the introduction of the second ligand phen group, the relative emission intensities and fluorescence lifetimes of the ternary complex EuL5L′(ClO4)32H2O (L=C6H5COCH2SOCH2COC6H5, L′=phen) enhanced more obviously than that of the binary complex EuL5(ClO4)33H2O. This indicated that the presence of both organic ligands bis(benzoylmethyl) sulfoxide and the second ligand phen could sensitize fluorescence intensities of Eu(III) ions, and the introduction of phen group was resulted in the enhancement of the fluorescence properties of the Eu(III) ternary rare earth complexes. The phosphorescence spectra are also discussed. 相似文献
2.
Abstract The 60 MHz 1H NMR spectra of paramethadione, 5-ethyl-3,5-dimethyl-2,4-oxazolidinedione, 1, have been studied at 28° in CDCl3 solution with the achiral reagent tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III), 2, and the chiral reagents tris[3-(trifluoromethylhydroxymethylene)?(+)-camphorato]europium(III), 3, and tris[3?(heptafluoropropylhydroxymethylene)?(+)-camphorato]europium(III), 4.SubstantiaΔδ values and spectral simplification are achieved with 2 or 4. Significant enatiomeric shift differences, ΔΔδ, are observed with 4 that should provide direct optical purity determinations of ? 1, using the C(5)CH3 or the NCH, signals with &;:Iratios of 1.3–1.5. Valley height for the CCH, resonance as low as 4.8% was achieved, which should allow detection of as little as 3–4% of the minor enantiomer. Results are discussed in terms of the structural features of I and of the LSR. Substantial nb values and spectral simplification 相似文献
3.
A novel supersonic plasma spraying was used to prepare rare earth oxide added Cr3C2-NiCr coatings. X-ray diffractometer, contact surface profiler, hardness tester, micro-friction and -wear tester, environmental scanning electron microscope equipped with energy dispersive spectroscopy were employed to investigate the phase structure, surface morphology, microhardness, and friction properties of deposited coatings, respectively. The results show that surface roughness, microhardness, brittle fracture, friction extent and wear resistance of rare earth oxide added Cr3C2-NiCr coatings are effectively improved compared with that of unadded one. The friction and friction mechanism are also discussed. 相似文献
4.
Eu-doped lutetia (Lu2O3:Eu) nano-phosphors were synthesized by the sol-gel combustion process from a mixed aqueous solution of europium and lutetium nitrates, using organic glycine as the fuel. Powder X-ray diffraction shows that cubic Lu2O3:Eu crystallites are directly obtained by the sol-gel combustion process without further calcination. Electron microscopy reveals that the as-prepared phosphors are agglomerated and have a fluffy, fine, and porous morphology, consisting of primary particle size of 8-10 nm. The excitation spectrum is characterized by three dominant bands centered at 395, 466, and 534 nm, respectively. Both the photoluminescent and radioluminescent spectra are very similar and exhibit intense emission peaks centered at 612 nm due to 5D0→7F2 transition of Eu3+ ions. The energy transfer from Lu2O3 host to Eu3+ activator is more efficient in the case of calcined phosphors than for the as-prepared phosphors due to their improved lattice perfection. 相似文献
5.
Hui Xu Chundu Wu Huaming Li Guangsong Sun Yongsheng Yan 《Applied Surface Science》2009,256(3):597-602
The BiVO4-based photocatalysts loaded with rare earth (RE=Ho, Sm, Yb, Eu, Gd, Nd, Ce and La) were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), diffuse reflectance spectroscopy (DRS), nitrogen adsorption for the BET specific surface area and X-ray photoelectron spectroscopy (XPS). The photocatalytic activities of the samples were evaluated by decolorization of methylene blue (MB) under visible light irradiation. The results of XRD, SEM and XPS analysis deduced that the rare earth ions were present as RE2O3 in the samples. The DRS analysis showed the shift in the absorbption edge from the UV to the visible range: Ho3+-BiVO4 < Sm3+-BiVO4 < Yb3+-BiVO4 < Eu3+-BiVO4 < Gd3+-BiVO4 < Nd3+-BiVO4 < La3+-BiVO4 < Ce3+-BiVO4 < BiVO4. Gd3+-BiVO4 had the highest photocatalytic activity among all the RE3+-BiVO4 catalysts. The optimal Gd content was 8 at% under visible light irradiation. This beneficial effect was attributed to the specific electron structure characteristics of gadolinium and the increasing in the separation efficiency of the electron-hole pairs. On the contrast, the other rare earth ions had the detrimental effect on the photocatalytic decolorization of MB. 相似文献
6.
Intense photoluminescence is reported for hydrated bromides of Gd, La and Y (LaBr3·7H2O, CeBr3·7H2O, YBr3·8H2O and GdBr3·n H2O) prepared by the wet chemical method and activated with Ce3+. Intensities are comparable to that for a commercial phosphor (SrB4O7:Eu2+—Sylvania 2052). Luminescence in hydrated salt is usually quenched. The observation of intense luminescence in hydrated bromides is remarkable. 相似文献
7.
Min Xu Feng-Juan Chen Liang Huang Pin-xian Xi Zheng-zhi Zeng 《Journal of luminescence》2011,131(8):1557-1565
The water-soluble Pr (Ⅲ) and Nd (Ⅲ) complexes with an ofloxacin derivative have been prepared and characterized. The single-crystal X-ray diffraction showed that the Pr (III) and Nd (III) complexes have the similar molecular structure. Under physiological pH condition, the effects of [PrL(NO3)2(CH3OH)](NO3) and [NdL(NO3)2(CH3OH)](NO3) on bovine serum albumin (BSA) were examined using fluorescence spectroscopy in combination with UV-vis absorbance and circular dichroism (CD) spectra. The result reveals that the quenching mechanism of fluorescence of BSA by two complexes is a static quenching process and the number of binding sites is about 1 for both. The thermodynamic parameters (ΔH=−14.52 kJ mol−1, ΔS=56.54 J mol−1 K−1 for [PrL(NO3)2(CH3OH)](NO3) and ΔH=−24.63 kJ mol−1, ΔS=22.07 J mol−1 K−1 for [NdL(NO3)2(CH3OH)](NO3)) indicate that hydrophobic and electrostatic interactions are the main binding force in the complexes-BSA system. The binding average distance between complexes and BSA was obtained on the basis of Förster's theory. In addition, it was proved by the CD spectra that the BSA secondary structure was changed in the presence of complexes in an aqueous solution. 相似文献
8.
Yu.V. Orlovskii T.T. Basiev N.A. Glushkov O.K. Alimov S.O. Klimonsky 《Journal of luminescence》2011,131(3):449-17460
We evaluated energy transfer probe for the characterization of luminescent photonic crystals morphology. It demonstrates a monomolecular filming of fluorescent chelated complexes inside photonic crystal voids. Either direct fluorescence quenching of excited fluorescent donors by the acceptors in case of low concentration of fluorescent centers or fluorescence quenching accelerated by energy migration over fluorescent donor ions in case of 100% of sites occupied by donors is demonstrated in 2D space contrarily to the powder samples of the same complexes where energy transfer occurs in 3D space. 相似文献
9.
Zhisong Xiao Bo Zhou Lu Yan Fang Zhu Feng Zhang Anping Huang 《Physics letters. A》2010,374(10):1297-6523
Tm-Er codoped amorphous aluminum oxide thin films were prepared by pulsed laser deposition. Broadband photoluminescence in the wavelength region of 1400-1700 nm comprised of two emissions at around 1532 and 1620 nm was observed. PL performance was investigated as a function of the substrate-heating temperature. Possible energy transfer processes involved in the heat treatment were discussed and nonradiative decay rates were evaluated, by comparing the inverse of measured lifetimes with the calculated radiative decay rates. Our results suggest that Tm-Er codoped Al2O3 thin film might be potential candidate as broadband light sources and amplifiers. 相似文献
10.
The 60 MHz 1H NMR spectra of mexiletine, 1-(2,6-dimethylphenoxy)-2-propanamine, 1, have been studied at 28° in CDCl3 solution with the achiral reagent, tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium(III), 2, Eu(FOD)3, and the chiral reagents tris[3-(trifluoromethylhydroxymethylene)-d-camphorato]europium(III), 3, Eu(FACAM)3, and tris[3-(heptafluoropropylhydroxymethylene)-d-camphorato]europium(III), 4, Eu(HFC)3. Substantial lanthanide-induced shifts were seen for the proton signals of 1 with each reagent. Appreciable enantiomeric shift differences were seen for both methyl signals and for each of the CH2CH proton signals using 3 and 4 that should permit direct determinations of enantiomeric excess for samples of 1. A predominant conformation for 1 is suggested based on observed splittings of the CH2 proton signals and their relative lanthanide-induced shifts. 相似文献
11.
Gd(OH)3 nanobundles, which consisted of bundle-like nanorods, have been prepared through a simple and facile hydrothermal method. The crystal, purity, morphology and structural features of Gd(OH)3 nanobundles are investigated by powder X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscopy (TEM), selected area electron diffraction (SAED) and energy dispersive X-ray (EDX). A possible formation mechanism of Gd(OH)3 nanobundles is briefly discussed. 相似文献
12.
Abstract The 60 MHz 1H NMR spectra of methastyridone, 2,2-dimethyl-5-(2-phenylethenyl)-4-oxazolidinone, 1, have been studied at 28° in CDCl3 solution with the achiral reagent tris(6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato)europium(III), 2, Eu(FOD)3, and the chiral reagent tris[3-(heptafluoropropylhydroxy-methylene)-d?camphorato]europium(III), 3, Eu(HFC)3. 相似文献
13.
Fan Yu-shan Song Hong-zhang Li Zhi-hui Yang De-lin Hu Xing 《Frontiers of Physics in China》2006,1(3):368-370
The oxygen adsorption-desorption properties of RBa2Cu3O7−δ
(R = Gd, Er, Eu, Dy, Sm, Ho and Nd) and Y1−x
LaxBa2Cu3O7−δ
(x=0.1, 0.5 and 1.0) were investigated from room temperature to 950 °C by thermogravimetry (TG). The results show that all samples
will release oxygen with the increasing of temperature and the released oxygen can be absorbed back into the sample when temperature
decreases. However, dependent on the rare earth element, the amount of the released oxygen is different for these samples.
Moreover, in the temperature increasing and decreasing circle the repetition of oxygen adsorption-desorption is also different. 相似文献
14.
A new family of UV-activated phosphors made by substituting rare-earth activators such as trivalent Eu, Tb, Tm and Er into A(1)3−xA(2)xMO4F host lattices (A(1)/A(2)=Sr, Ca, Ba; M=Al, Ga) are introduced and their activation and emission spectra as well as their CIE values reported. The Tm-substituted system can be activated using light with a wavelength of 360 nm. Relative intensities of a family of Tb-substituted green phosphors activated at 254 nm and with emissions centered near 548 nm are discussed. 相似文献
15.
H.C. Swart O.M. NtwaeaborwaP.D. Nsimama J.J. Terblans 《Physica B: Condensed Matter》2012,407(10):1660-1663
SrAl2O4:Eu2+, Dy3+ thin films were grown on Si (1 0 0) substrates in different atmospheres using the pulsed laser deposition (PLD) technique. The effects of vacuum, oxygen (O2) and argon (Ar) deposition atmospheres on the structural, morphological and photoluminescence (PL) properties of the films were investigated. The films were ablated using a 248 nm KrF excimer laser. Improved PL intensities were obtained from the unannealed films prepared in Ar and O2 atmospheres compared to those prepared in vacuum. A stable green emission peak at 520 nm, attributed to 4f65d1→4f7 Eu2+ transitions was obtained. After annealing the films prepared in vacuum at 800 °C for 2 h, the intensity of the green emission (520 nm) of the thin film increased considerably. The amorphous thin film was crystalline after the annealing process. The diffusion of adventitious C into the nanostructured layers deposited in the Ar and O2 atmospheres was most probably responsible for the quenching of the PL intensity after annealing. 相似文献
16.
The potent nonsteroidal anti-inflammatory agent, sulindac, (Z) -5-fluoro-2-methyl-1-{[4-(methylsulfinyl) - phenyl]methylene} -1H-indene-3-acetic acid, has been examined by 1H NMR as its methyl ester in CDCl3 solution with the added achiral lanthanide shift reagent (LSR) tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium (III), Eu (FOD)3, 2, for spectral simplification, and with the chiral LSRs, tris[3-(heptafluoropropylhydroxymethylene) - (+) - camphorato] europium (III), 3, and tris[3-(trifluoromethyl-hydroxymethylene) - (+) -camphorato] europium (III), 4, to induce enantiomeric shift differences (ΔΔδ) for several nuclei. Studies employed 60 and 300 MHz spectrometers. At the higher frequency, analytically useful ΔΔδ values were observed with added 3 for the aryl protons ortho to the methylsulfinyl group that should permit direct determinations of enantiomeric excess (% ee). By conversion of sulindac samples to the methyl ester, use of 3 would then formally constitute an ee determination of sulindac. 相似文献
17.
18.
X.H. Zhao K.L. Huang F.P. Jiao Z.G. Liu 《Journal of Physics and Chemistry of Solids》2007,68(9):1674-1680
This work reports the synthesis and luminescent properties of complexes of europium(III) with 2-thienyltrifluoroacetonate (HTTA), terephthalic acid (TPA) and phenanthroline (Phen), in the solid state. The new complexes were characterized by elemental analysis, infrared (IR) spectroscopy, scanning electronic microscopy (SEM) and thermal stability analysis. Both binuclear complex Eu2(TPA)(TTA)4Phen2 and polynuclear complex Eu(TPA)(TTA)Phen present better thermal stability than the mononuclear complex Eu(TTA)3Phen does. The formation of the binuclear/polynuclear structure of the complexes appears to be responsible for the enhancement of the thermal stability. The emission spectra show narrow emission bands that arise from the 5D0→7FJ (J=0-4) transition of the Eu3+ ion. The spectral data of the complexes Eu(TPA)(TTA)Phen and Eu2(TPA)(TTA)4Phen2 present only one sharp peak in the region of the 5D0→7F0 transition indicating that only one Eu3+ ion species is present in each sample. In addition, the luminescence decay curves of the complexes Eu(TPA)(TTA)Phen and Eu2(TPA)(TTA)4Phen2 fit a single-exponential decay law. The values of quantum efficiencies of the emitting 5D0 level for the complexes Eu(TPA)(TTA)Phen and Eu2(TPA)(TTA)4Phen2 are 29% and 28%, respectively. 相似文献
19.
Y1.9−xLi0.1EuxO3 (x=0.02, 0.05, 0.08, and 0.12) films were fabricated by spin-coating method. A colloidal silica suspension with Y1.9−xLi0.1EuxO3 phosphor powder was exploited to obtain the highly stable and effective luminescent films onto the glass substrate. After heating as-prepared Y1.9−xLi0.1EuxO3 films at 700 °C for 1 h, the phosphor films exhibit a high luminescent brightness as well as a strong adhesiveness on the glass substrate. The emission spectra of spin-coated and pulse-laser deposited Y1.82Li0.1Eu0.08O3 films were compared. The cathodoluminescence of the phosphor films was carried out at the anode voltage 1 kV. 相似文献
20.
The 60 MHz H NMR spectra for the herbicide, diclofop methyl, 1, have been studied in CDCl3 solution at 28±1° with the added achiral lanthanide shift reagent (LSR) tris (6,6,7,7,8,8,8-heptafluoro-2,2-dimethyl-3,5-octanedionato) europium(III), Eu (FOD)3, 2, and with the chiral LSRs, tris[3-(heptafluoropropylhydroxymethylene)-(+)-camphorato]europium(III)3, Eu(HFC)3, 3, and tris[3-(trifluoromethylhydroxymethylene)-(+)-camphorato]europium(III), Eu(FACAM)3, 4. Both 2 and 3 produced substantial lanthanide-induced shifts (LIS) consistent with predominant LSR binding at the ester carbonyl. Much smaller LIS magnitudes were observed with 4. Modest enantiomeric shift differences (ΔΔδ) were elicited with 3 for the OCH3 and the CCH3 resonances of 1. The former signal appears to offer greatest potential for the direct determination of enantiomeric excess of samples of 1, with 3:1 molar ratios ca. 0.3–0.4 resulting in valley heights as low as 33% of the average peak heights of the OCH3 signals of the two enantiomers. 相似文献