Synthesis and Characterization of Mesostructured Silica Doped with Acyl‐Hydroxy‐Pyrazole Derivatives. Sorption Tests of Cu(II) and Eu(III)

Abstract

The synthesis and the characterization of mesostructured silica doped with acidic acyl‐hydroxy‐pyrazoles like extractants are described. The extractants have either a single chelating site, 1‐phenyl‐3‐methyl‐4‐stearoyl‐5‐hydroxy‐pyrazole (HPMSP), or two chelating sites, 1,12‐bis(1′‐phenyl‐3′‐methyl‐5′‐hydroxy‐4′‐pyrazolyl)‐dodecane‐1,12‐dione (HL‐10‐LH). The so‐called doped silicas were synthesized in basic medium according to a sol‐gel process beginning with the solubilization of the extractant in a micellar phase followed by the precipitation of silica around micelles. The chemical composition of the synthesized materials, especially the ligand content, was determined. High quantities of ligand loadings (up to 0.69 mol/kg) are reached. The materials obtained were characterized by X‐ray diffraction, laser granulometry, transmission and scanning electron microscopy and, after calcination, by nitrogen physisorption. Un‐doped silica is mesostructured, lamellar, and has high pore diameter as well as high specific surfaces. Doping induces the disorganization of the lamellar structure, the increase of the pore diameter, and a slight decrease of the specific surface. The capacities of extraction of Cu(II) and Eu(III) by the doped materials and the corresponding extraction rate were measured: high values are reached.     

Microstructure and optical properties of Eu-doped Mg_xZn_(1-x)O hexagonal nanocrystals

Eu-doped MgxZn1-xO hexagonal nanocrystals with wurtzite-type structure were fabricated on quartz substrates by electron beam evaporation using Mg0.15Zn0.85O:Euy(0≤y≤0.08)target combined thermal annealing followed with rapid cooling.The influence of Eu on the microstructure and optical properties of MgxZn1-xO hexagonal nanocrystals had been investigated using X-ray diffraction spectra,X-ray photoelectron energy spectra,scanning electron microscopy,absorption spectra,and photoluminescence spectra.It was found...     

Van Vleck paramagnetism of europium oxyhydroxide

Europium oxyhydroxide crystals were synthesized by the flux method. The as-grown crystals were transparent and had a plate-like shape with natural flat surfaces. The powder XRD data were refined by assuming a monoclinic structure of the space group P21/m and lattice parameters of a=0.4346 nm, b=0.3744 nm, c=0.6107 nm, and β=108.62°. The magnetic susceptibility of the EuOOH crystals exhibited typical Van Vleck temperature-independent paramagnetism below 120 K. The calculated susceptibility, based on Van Vleck’s theory, agreed with the experimental data to some extent, with the coupling constant λ=458±10 K. The experimental results were in close agreement with the results calculated using a modified formula with λ=505±2 K and a constant term C=4.6×10-4 emu/(mol·Oe).     

掺杂Eu~(3+)或Tb~(3+)的(Gd,Lu)_2O_3粉体的发光性能

采用高温固相法在空气中合成了(Od,Lu)2O3,(Gd,Lu)2O3:Eu3+和(Gd,Lu)2O3:Tb3+系粉体.研究了二元系中Lu2O3的摩尔分数对抑制Gd2O3高温相变、粉体的发光性质和光谱性质的影响.结果表明:在(Gd,Lu)2O3系粉体中,当Lu2O3的摩尔分数(下同)大于40%时,能在煅烧温度不低于1 700℃情况下,抑制Gd2O3的相变得到利于制备透明陶瓷的立方相结构.而且随着Lu3+离子的浓度增加,先后观察到红移和蓝移现象;在(Gd,Lu)203:Eu3+系粉体中,粉体的发光强度随着Lu3+掺杂量增加而减小,Eu3+的最佳掺杂量为7%;在(Gd,Lu)2O3:Tb3+系粉体中,Tb3+离子的最佳掺量为1%.     

Facile Synthesis of Highly Efficient and Thermally Stable BaAl4Sb2O12:Eu2+ Phosphor in Air

Despite many Eu²⁺-doped phosphors having been synthesized by different methods, a simple synthetic strategy for Eu²⁺-doped high-performance phosphors remains one of the significant challenges for phosphor-conversion white light-emitting diodes. Herein, a novel broad-band excitation yellow phosphor Ba_0.985Al₄Sb₂O₁₂:0.015Eu²⁺ (BASO:Eu²⁺) with high thermal stability (423 K, 94%) and internal quantum efficiency (96.7%) are reported. More importantly, the novel phosphor is synthesized by solid-state reaction at high temperatures in air. Structural and spectral analyses show that the Eu²⁺ ions in BASO preferably occupy [BaO₈] hexahedra, forming a single luminescence center. This study provides a reliable direction for the facile synthesis of high-performance Eu²⁺-doped phosphors in air.     

Synthesis and Photoluminescence of Three Europium (Ⅲ) Ternary Complexes with New Secondary Ligands of Different Structure

Three new 1,10-phenanthroline derivatives, dipyrido (3,2-f: 2,3-h) quinoxaline (DPQN), imidazo (5,6-f)-(1,10)-phenanthroline (IP) and 3-phenyl-imidazo (5,6-f)-(1,10)-phenanthroline (PIP) were designed and synthesized as a secondary ligand to coordinate with europium (Ⅲ) ion while dibenzoylmethane (DBM) was used as the first ligand. The compositions of the ligands and the europium (Ⅲ) ternary complexes were confirmed by elementary analysis, IR and 1H-NMR spectroscopy. The UV-visible absorption spectra, thermal stability, photoluminescence spectra, quantum yield and fluorescence life time of the Eu(Ⅲ) complexes were investigated. The effect of the structure of the secondary ligand on the photoluminescence of the complexes was discussed. The results show that the synthesized Eu(Ⅲ) complexes are good red-emitiing materials for potential application in fabrication of organic electroluminescence devices.     

Preparation and Luminescent Characteristics of LaPO_4∶Eu Nanoparticles and Nanowires

Itiswellknownthatreductionofparticlesizeofcrystallinesystemcanresultinremarkablemodifica tionoftheirpropertieswhicharedifferentfromthoseofbulkbecauseofhighsurfacetovolumeratioandquan tumconfinementeffectofnanometermaterials .In1994 ,Bhargavaetal .reportedthatradiativetransi tionrateofMn2 ionsinZnSnanocrystalincreasedsixorderincomparisonwithbulkone[1] .Despitethisre sultwasstronglycriticizedlater ,studiesonnanosizedluminescentsemiconductorattractedgreatinter ests[2～ 4 ] .Sincecompoundsofra…     

以铕离子为荧光探针测定痕量依诺沙星

详细研究了依诺沙星(enoxacin,ENX)同铕离子形成的配合物体系的荧光光谱特性及实验条件对荧光强度的影响。在pH为8.10的条件下,Eu3+和依诺沙星(ENX)能形成配合物发生分子内能量转移,发射铕离子的特征荧光,加入阴离子表面活性剂十二烷基硫酸钠(SDS)后,大大增强了体系的荧光强度,其最大激发和发射波长为273nm和615nm。据此建立了一种以铕离子为荧光探针分析痕量依诺沙星含量的新方法,方法的线性范围为3.1×1-06mol.L-1~3.1×1-05mol.L-1,检出限为1.2×1-07mol.L-1。该法用于依诺沙星片剂的测定,回收率在98%~103%之间,结果令人满意。     

铕-镧-柠檬酸-1,10-菲咯啉配合物荧光性能研究

分别合成了铕与柠檬酸配位的二元配合物，铕、柠檬酸、1，10－菲咯啉配位的三元配合物和掺杂不同量镧的多核三元配合物。经过元素分析、红外分析和热重差热分析等手段确定了配合物的组成与结构。通过荧光光谱及荧光寿命测试了其荧光性能，结果表明当铕与镧掺杂摩尔比为6：4时能得到荧光强度最强且荧光寿命最长的稀土配合。实验结果拟合表明，当铕镧摩尔比在1：9－5：5时，镧离了对铕荧光的敏化程度以指数形式衰减，当铕镧摩尔比在6：4－9：1时，镧离子对铕荧光的敏化程度以线性方式衰减。     

1-苯基-3-甲基-4-氰硫基-5-吡唑酮的合成及其对镅和铕的萃取研究

合成了1-苯基-3-甲基-4-氰硫基-5-吡唑酮(PMTCP),研究了该试剂单独萃取及其与2,2’-联吡啶协同萃取镅和铕的行为。实验结果表明,该试剂单独萃取镅和铕的能力都比较低,但优先萃取镅;含氮协萃剂2,2’-联吡啶的加入可以明显提高镅的萃取率,并将镅和铕的分离因数α(Am／Eu)由PMTCP单独萃取时的2.6提高到4．0。