STUDIES ON RARE EARTH COMPLEXES WITH CROWN ETHERS ⅩⅧ——Synthesis,Characterization and Crystal Structure of[Sc(NO_3)_3(H_2O)_2]·(15-Crown-5)

The single crystal of the complex [Sc(NO_3)_3(H_2O)_2]·(15C5) has been prepared in acetonitrile.The new complex has been characterized by elemental analysis,IR spectra,solubility and molar conductance measurements.The structure of the complex is determined by single crystal X-ray diffraction analysis.

Thermodynamic Study on the Rare Earth Vapour Complex PrAl_3Cl_(12)

Thermodynamic study on the reaction PrCl 3(s) +( x /2) Al 2Cl 6(g) =PrAl x Cl 3 x +3(g) was carried out by quenching experiments within 604～827 K and 0 05～0 15 MPa. The results suggested that the PrAl 3Cl 12(g) complex was the predominant species. The equilibrium constants of the reaction were measured. The reaction enthalpy and entropy derived from the measurements were ΔH 0 298 =(38 2±2) kJ·mol -1 and ΔS 0 298 =(1 2±3) J·mol -1 ·K -1 .

Novel Approach to Characterization of Rare Earth Complexation with 1, 5-Bis(2-Hydroxy-5-Chlorphenyl)-3-Cyanoformazan in Presence of Cetyltrimethylammonium Bromide

The ternary interaction of 1, 5 bis(2 hydroxy 5 chlorphenyl) 3 cyanoformazan (HCPCF) with cetyltrimethylammonium bromide (CTAB) and rare earths (RE: Yb, Dy, Er and Eu) was investigated at pH 9.84 by the microsurface adsorption spectral correction technique (MSASC). The aggregation of HCPCF on CTAB obeys the Langmuir isothermal adsorption and the interaction of RE with the HCPCF CTAB aggregate was first found to accord with the monolayer binding. The effects of temperature and ionic strength of solution on the aggregations were made. The binary aggregate and the ternary complex were characterized.

Synthesis,characterization and fluorescence of N,N'-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane and corresponding rare earth (Ⅲ) complexes

A new ligand, N,N-BIS (6-metyl-2-pyridinecarboxylamide-N-oxide)-1,2-ethane (L) and six lanthanide(Ⅲ) complexes (RE=La, Sm, Eu, Tb, Gd, Yb) were synthesized and characterized in detail. The results indicated that the composition of the binary complexes was determined as [REL(H2O)(NO3)2]NO3·nH2O (n=0-2), and the Eu3+ complex had bright red fluorescence in solid state. Three complexes of Eu3+, Tb3+, and Gd3+ with 6-methylpicolinic acid N-oxide (L’) were also synthesized. The relative intensity of sensitized luminescence for Eu3+ increased in the following order: L>L’. The phosphorescence spectra of the Gd3+ complexes at 77 K were measured. The energies of excited triplet state for the ligands were 20704 cm-1 (L) and 20408 cm-1 (L’). The facts that the ligands sensitized Eu3+ strongly and the order of the emission intensity for Eu3+ complexes were explained by ΔE(T-5D). This meant that the triplet energy level of the ligand was the main factor to influence RE3+ luminescence.

Synthesis and properties of Tb^(3+) isomultiligand complexes

Four kinds of terbium containing monomers were synthesized by the reaction of Tb isoproxides with acrylic acid and β diketones. The composition and structure of these monomers were confirmed by FT IR, UV spectroscopy and elemental analysis. DTA and TG analyses reveal that the decomposition temperature of these monomers is in the range of 190～200 ℃. The fluorescence properties of these monomers were studied. Under the excitation of UV light, these monomers exhibit characteristic luminescence of terbium ion, the fluorescent intensity is affected by the polarity of solvent and triplet state of ligand. In solid state, the monochromatic index of luminescence is enhanced.

Synthesis of 1-(2-Hydroxyphenyl)-3-Phenyl-1,3-Propanedione and Luminescence Properties of Its Europium Complexes

Using 2＇-Hydroxyacetophenone and as the raw material, 1-（ 2-Hydroxyphenyl ）-3-Phenyl-1, 3- Propanedione （HPPPD） was synthesized by esterification reaction and Fries rearrangement reaction. And the complexes of HPPPD with europium were also synthesized. The compounds were characterized by IR, thermo-gravimetric analysis and ^1H-NMR. The effects of phenolic hydroxyl on the luminescence properties of complexes were studied. The results show that the complexes emit strong red fluorescence and the fluorescence intensity of the ternary complex is better than that of the duality. But the complexes of HPPPD with Sm（ Ⅲ ）, Tb （ Ⅲ ）, Dy （ Ⅲ ） emit weak fluorescence. The phenomenon was interpreted by electron-effect and energy-matching mechanism. Energy transfer mechanism of the luminescence in the complex was discussed.

Interaction between DNA with Complex of Eu^(3+)-Rutin by UV-Visible Spectroscopy and Electrochemistry

The interaction of Eu^3＋-rutin with CT DNA was studied by UV-visible spectroscopy and electrochemistry. All experimental results indicate that the complex binds to DNA by the electrostatic mode and the groove binding mode. Information such as intrinsic binding costant （ k = 1. 426 × 104 mol·L^-1 ）, and binding numbers （ n = 2）, were determined by cyclic vohammetry and differential pulse vohammetry at glass carbon electrode. Interaction between Eu^3＋ with rutin was also studied by UV-visible spectroscopy.

Synthesis, Characterization and Properties of N,N′-Bis(6-methyl-2-pyridine-N-oxide)-1,3-Propane and Europium and Terbium Complexes

A new ligand, N,N′-Bis(6-methyl-2-pyridine-N-oxide)-1,3-propane (L), and some binary lanthanide complexes (Ln=Eu^(3+), Tb^(3+)) were synthesized and characterized in detail. The composition of the binary complexes was determined as LnL(NO_3)_3. They are 1∶1 electrolytes in DMF. The complexes have strong characteristic line fluorescence emission spectra, and it is also found that TbL(NO_3)_3 complex has stronger luminescence intensity than EuL(NO_3)_3 in solid state and in methanol.

Syntheses and Characterizations of Cu Ln Heterobinuclear Complexes with Schiff Base from 3-Formylsalicylic Acid and Ethylene Diamine

Seven heterobinuclear complexes of Cu-Ln with N, N'-bis(3-carboxylsali cylidene) ethylenediamine(ES) were synthesized and characterized by elemental analysis, molar conductivity, thermogravimetry, IR and electronic spectra. The room temperature magnetic moments show that there are basically no spin exchange interactions between the ions of Cu2+ and Ln(3+) in the CuLnESCl . nH(2)O compounds.

On the Rare Earth Chelates of(1'-Phenyl-3'-Methyl-5'-Pyrazolone-4')-Carbonylmethanoic Acid and 1,10-Phenanthroline

Some rare earth chelates of(1'-phenyl-3'-methyl-5'-phrazolone-4')-carbonylmethanoic acid and 1, 10-phenanthroline have been synthesized.The composition of the complexes were confirmed by elemental analy. sis.The molar conductance,IR,~4H-NMR,electronic spectra and thermogravimetric analysis of the chelates have been measured and discussed.

Catalytic Reduction of SO_2 on CeO_2-La_2O_3 Rare Earth Mixed Compounds

Adding rare earth oxide CeO_2 with variable valences to La_2O_3 formed a mixture of rare earth oxides. By means of dipping CeO_2, La_2O_3 and their mixture, whose carriers were all γ-Al_2O_3, were used as the catalyst for the reduction of SO_2 by CO. The activation process of this catalyst and the impact of temperature and reactant concentration on the activation process were investigated. Using X-ray diffraction, the structure characteristics of catalyst before and after reaction were analyzed to reveal the change of phase structure. The result shows that the rare earth oxide mixtures composing of CeO_2 and La_2O_3, as the catalyst for the reduction of SO_2 by CO, diminish activation temperature 50～100 ℃ less and have higher activity than a single oxide CeO_2 or La_2O_3. The reason possibl is that La_2O_3 goes into in the lattice of CeO_2 to form solid phase complex CeO_2-La_2O_3 and increases the capability of CeO_2-La_2O_3/γ-Al_2O_3 catalyst to store oxygen, which supplies the redox of CeO_2 reaction with a better condition. At the same time, elemental sulfur formed in the redox reaction impels La_2O_3 to be transformed to activation phase La_2O_2S in a lower temperature, which can be explained with the synergism between redox reaction and COS intermediate mechanism reaction.

Eu^(3+)配合物掺杂聚合物的制备与光谱性能研究

以噻吩甲酰三氟丙酮(2-thenoyltrifluoroacetone,TTFA),六氟乙酰丙酮(hexafluoro-acetylacetone,HFA)和甲基联苯甲酰(dibenzoylmethide,DBM)分别为配体合成了Eu3+的三种β-二酮类配合物Eu(TTFA)3、Eu(HFA)3和Eu(DBM)3,以及掺杂这三种配合物的聚合物(聚甲基丙烯酸甲酯,PMMA),并用分光光度计对它们的荧光光谱特性进行了分析研究.结果表明,三种配合物中Eu(TTFA)3荧光强度最强,并分析了其原因,发现能级匹配、配体取代基、配体结构对称性等均对配合物发光效率有重要的影响.通过比对,证明了TTFA是Eu3+发红色荧光的优良配体.进一步研究还发现,Eu(TTFA)3掺杂PMMA中稀土离子的荧光强度和荧光寿命均随掺杂浓度(质量分数为0.08~0.5)的增加而增大.

紫外光固化掺铕(Eu^(3+))聚氨酯膜的制备与性能

本文制备了掺铕的紫外光固化聚醚型聚氨酯膜 ,研究了光固化时间和铕浓度对膜的荧光性能影响 ,用扫描电镜及热重分析仪测定其均匀性和热稳定性。发现开始时膜的荧光强度随固化时间增加而增强 ,其后随固化时间的延长而减弱 。

Eu^(3+)-芦丁配合物与DNA相互作用的电化学和紫外可见吸收光谱研究

在0.1mol.L-1乙酸缓冲溶液中(pH=5.69),用电化学方法和吸收光谱法研究了Eu3+-芦丁配合物和小牛胸腺DNA的相互作用。发现Eu3+-芦丁配合物与DNA通过静电吸引和沟槽键合模式键合。在玻碳电极上通过循环伏安法和差示脉冲法得到了键合常数(K=1.42×104mol.L-1)和键合位点数(n=2)。用紫外可见吸收光谱研究了Eu3+和芦丁的相互作用,以及Eu3+-芦丁配合物与DNA的相互作用。

稀土配合物前驱体热分解法合成Y_2O_3:Eu^(3+)纳米材料

Nano Y2O3:Eu3+ fluorescence powder was prepared by thermal decomposition of the rare earth citric acid complexes.The structure,size,morphology and luminescent properties of fluorescence powder were investigated by means of XRD and TEM.The results show that the crystal structure of nano Y2O3:Eu3+fluorescence powder is cubic,and the size of the particles is between 20 nm and 60 nm.The phosphors has the maximum excitation peak at 248 nm,and the maximum emission peak at 615 nm.

Interpretation of the 4f-5d Excitation Spectra of Eu^(3+) and Tb^(3+) Doped in Crystals

The structure of the low-temperature 4f^N→4f^N-15d excitation spectra of Eu^3＋ and Tb^3＋ doped in crystals LiYF4, YPO4 and CaF2 measured by van Pieterson et al. in 2002 was analyzed and assigned based on the simple model proposed by Duan and co-workers in the last few years. Some complemental discussion on effects of J-mixing on the f-d transition intensities for Eu^3＋ due to the f-electron crystal-field interaction Hcf（f）, which was ignored in the simple mod- el, was presented. Some previously unexplained peaks for Tb^3 ＋ were interpreted to be spin-forbidden transitions to higher 5d crystal-field levels, or assigned to be f→d excitations with the core 4f7 excited from ^8S to ^6P, ^6I and ^6D, respectively. It is shown that the main structure of 4f-Sd excitation spectra of Eu^3＋ and Tb^3＋ can be well interpreted with the simple model.

Preparation of Non-Grinding Long Afterglow SrAl_2O_4:Eu^(2+), Dy^(3+) Material by Microwave Combustion Method

The non-grinding long afterglow material SrAl2O4：Eu^2＋ , Dy^3＋ was prepared by combustion method in home mierowave oven direetly, after dispersant, frother, eomburent, and mineralizer were added into the reacting system. XRD analysis showed that the powders were nearly pure SrAl2O4 phase with few other phases, and the size of the grain was 41.1 nm. Fluoreseenee speetrum results indieated that there were 2 exeitation peaks loeated at 345 and 400 nm, and the emission peak loeated at 516 nm, afterglow lasted up to 30 min or more. The mierowave eombustion method has advantages of less time, low temperature and no grinding process, and the material made by the method has good luminescent property.

Luminescent characteristics of Ba_3Y_2(BO_3)_4:Eu^(3+) phosphor for white LED

The Ba3Y2（BO3）4：Eu^3＋ phosphor was synthesized using a high temperature solid-state reaction method and the luminescent characteristics were investigated. The emission spectrum exhibited one strong red emission at 613 nm, corresponding to the electric dipole 5D0-TF2 transition of Eu^3＋, under 365 nm excitation. The excitation spectrum of 613 nm indicated that the Ba3Y2（BO3）n：Eu^3＋ phosphor was effectively excited by ultraviolet （UV） （254, 365 and 400 nm） and blue （470 nm） light. The effect of Eu^3＋ concentration on the 613 nm emission of the Ba3Y2（BO3）n：Eu^3＋ phosphor was measured. The results showed that the emission intensity increased with increasing Eu^3＋ concentration, and then decreased. The CIE color coordinates of Ba3Y2（BO3）4：Eu^3＋ phosphor were x=0.641 and y=0.359 at 15 mol.% Eu^3＋.

Luminescent Properties of Green Phosphor Ca_8Mg(SiO_4)_4Cl_2:Eu^(2+), Dy^(3+) for LED Applications

The new phosphor calcium magnesium chlorosilicate, codoped with Eu^2＋ and Dy^3＋, was synthesized with the help of the high temperature solid state reaction in reducing atmosphere. The excitation and emission spectra were very similar to that of Ca8Mg（SiO4）4Cl2 ：Eu^2＋, and the Dy^3＋ concentration influenced the emission intensity of this phosphor. The intensity of Eu^2＋ and Dy^3＋ codoped CMSC was stronger than that of Eu^2＋ singly doped CMSC. The emission spectrum of the Dy^3＋ ion overlapped the absorption band of the Eu^2＋ ion, indicating that an energy transfer from Dy^3＋ to Eu^2＋ took place in CMSC：Eu^2＋, Dy^3＋ phosphor. The mechanism of the energy transfer from Dy^3＋ tO Eu^2＋, in this phosphor, might be resonant energy transfer.

Photoluminescence properties of LaF_3:Eu^(3+) nanoparticles prepared by refluxing method

The europium-doped LaF3 nanoparticles were prepared by refluxing method in glycerol/water mixture and characterized with X-ray diffraction（XRD）, field emission scanning electron microscopy（FE-SEM）, UV-vis diffuse reflectance spectrum, and photoluminescence spectra.The results of XRD indicated that the obtained LaF3：Eu^3＋ nanoparticles were well crystallized with a hexagonal structure.The FE-SEM image illustrated that the LaF3：Eu^3＋ nanoparticles were spherical with an average size around 30 nm.Under irradiation of UV light, the emission spectrum of LaF3：Eu^3＋ nanoparticles exhibited the characteristic line emissions arising from the 5D0→7FJ（J=1, 2, 3, 4） transitions of the Eu3＋ ions, with the dominating emission centered at 590 nm.In addition, the emissions from the 5D1 level could be clearly observed due to the low phonon energies（-350 cm^-1） of LaF3 matrix.The optimum doping concentration for LaF3：Eu3＋ nanoparticles was determined to be 20mol.%.