Luminescence study of europium（Ⅲ） tris（β-diketonato）/phosphonate complexes in chloroform

The extraction of Eu（Ⅲ） with β-diketone, HA, and monodentate or bidentate Lewis bases, B, into chloroform and the luminescence properties of the extracted species were studied. Pivaloyltrifluoroacetone, Hpta, and 2-thenoyltfifluoroacetone, Htta, were used as the β-diketones. The Lewis bases, B, were tetraethyl methylene diphosphonate, POPO, which was bidentate, and diethyl benzylphosphonate, PhPO which was monodentate. Based on the extraction data, the stability constants, log β, of the first complexes between tfis（β-diketonato）Eu（Ⅲ） and the phosphonate, EuA3B, were determined to be 6.0 for the POPO complex and 3.40 for the PhPO complex. The Eu（Ⅲ） luminescence intensity in the EuA3POPO was larger than EuA3 where A was either pta or tta at similar concentrations of Eu（Ⅲ）, while that in Eu（pta）3PhPO was stronger than EuA3; however, in Eu（tta）3PhPO, it was weaker than Eu（tta）3. The POPO functions as a sensitizer, and the PhPO functions as a quencher for the tta chelate and as a sensitizer for the pta chelate. From the lifetime and quantum yield, φ, of the Eu（Ⅲ） luminescence in the complexes as well as the observation of the extractability of Eu（Ⅲ） with the Hpta and the phosphonates and of the luminescence spectra of the complexes, it was confirmed that the extraction of Eu（Ⅲ） was remarkably enhanced with a β-diketonate and a strong Lewis base, and also the ternary complex that was formed as the extracted species, showed luminescence enhancement. This phenomenon may be due the formation of a strong bond between the Eu（Ⅲ） and the strong Lewis base leading to more hydrophobicity in the extracted species and also to more effective energy transfer from the Lewis base to the Eu（Ⅲ）. It was not significant whether the donor atoms were N or O.     

Pr（Ⅲ） and Nd（Ⅲ） Absorption Spectroscopic Probe to Investigate Interaction with Lysozyme （HEW）

Pr（ Ⅲ ） and Nd（ Ⅲ ） can be utilized as absorption spectroscopic probes to investigate the interaction of biomolecules like Lysozyme （HEW） with Ca（ Ⅱ ） in-vitro ; the most abundant metal ion in the human body system. The spectroscopic techniques involving comparative absorption, absorption difference, and quantitative intensity analysis using 4f-4f transitions are utilized for changes in the inner sphere coordination pattern of Pr（ Ⅲ ） and Nd（Ⅲ ） in solution as well as in solid state. The present study deals with an important biomolecule in human metabolism, that is, Lysozyme （HEW）. The absorption er-Condon the probab spectral parameters such as the oscillator strength （P）, the Judd-Ofelt （Tλ） intensity parameters, and the Slatinter electronic parameters are calculated using chi square methods. The obtained results are used to determine le geometry of the complex in the solution, the nature of the bond between Pr（Ⅲ）/Nd（Ⅲ） with lysozyme, and the inner sphere coordination environment of f-f transitions. The results obtained from various experimental conditions are utilized to investigate the coordination changes in the Pr（Ⅲ）/Nd（Ⅲ） complexes caused by different coordinating sites of lysozyme, normalized bite, denticity, the solvent nature, the coordination number, the nature of bond and other parameters to mimic the interaction of the Ca（ Ⅱ ） ion with such biomolecule.     

Study on Luminescence Properties of a Novel Rare Earth Complex Eu（ TTA）2 （N-HPA） Phen

A novel rare earth complex Eu（TTA）2（N-HPA）Phen （TTA = thenoyltrifluoroacetone, N-HPA = N-phenylanthranilic acid, and phen = 1,10-phenathroline ）, which contains three different ligands, was synthesized. The Eu complex was blended with poly N-vinylcarbazole （PVK） in different weight ratios and spin coated into films. The luminescence properties of films were investigated and energy transfer between PVK and the complex was discussed. Multilayer structural devices consisting of ITO/PVK： Eu （TTA）2 （N-HPA） phen/BCP/Alq3/Al were fabricated with PVK ： Eu （TTA）2（N-HPA） as light-emitting layer. Increasing the concentration of Eu in the PVK thin film would inhibit the emission of PVK to different degrees. Finally, the pure red luminescence of europium（ Ⅲ ） was observed when the doping weight ratio was approximately 1 ： 5, which indicated an effective energy transfer from PVK to rare earth complex.     

Synthesis,spectroscopic characterization,and thermal decomposition kinetics of some lanthanide（Ⅲ） nitrate complexes of 2-（N-o-hydroxyacetophenone） amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene

Complexes of La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Dy（Ⅲ）, Yb（Ⅲ）, and Lu0ID with 2-（N-o- hydroxyacetophenone）amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene （HAAT） formed by the condensation of o-hydroxyacetophenone and 2-amino-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene were synthesized and characterized on the basis of elemental analyses, molar conductance measurements, magnetic susceptibility data, UV-Visible, IR, and NMR spectral studies. The spectral data revealed that the ligand acted as a neutral tridentate coordinating to the metal ion through ONO donor sequence. A coordination number nine was proposed for the complexes. Thermal decomposition studies of the ligand and lanthanum（Ⅲ） complex were carried out and kinetic parameters were calculated using Coats-Redfem equation. The decomposition reactions followed random nucleation mechanism with one nucleus on each particle.     

Preparation of Eu （ TTA ）2 phen （ MA ）/SiR Fluorescent Materials under High Mechanical Blending Temperature

Eu（TTA）2（phen）（MA） complexes were synthesized, in which MA was introduced as the acidic ligand to increase the fluorescent intensity of the complexes. The complexes were characterized by scanning electron microscopy （SEM）, X-ray diffraction （XRD）, and fluorescent spectra, respectively. Different amounts of rare earth complexes were blended with silicon rubber over the melting point of Eu （TTA） 2 （phen） （MA）. Next, a definite amount of 2,5-dimethyl-2, 5-di （tert-butylperoxy） hexane was added as a cross linker to the composite, to get the uncured composites. Subsequently, the composites were vulcanized at 160℃, and silicon rubber-based composites with different contents of the complexes were prepared and their fluorescent properties were observed. The contents of rare earth complexes were 0.96 %, 2.83 %, 4.63 % and 6.36 % （mass fraction）, respectively. Moreover, the composites of Eu （TTA） 2 （phen） （ MA ）/SiR were measured by SEM, XRD, and fluorescent spectra. The measurement result shows that the fluorescent intensity of uncured rubber is similar to one of the pure rare earth complexes. However, there is no marked change of fluorescent intensity in the uncured rubber when the content of rare earth complexes continues to increase.     

Effect of pH on sorption for RE（Ⅲ） and sorption behaviors of Sm（Ⅲ） by D152 resin

The pH dependent sorption of rare earth ions （La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Y（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, Gd（Ⅲ）, Tb（Ⅲ）, Dy（Ⅲ）, Ho（Ⅲ）, Er（Ⅲ）, Lu（Ⅲ）, and Yb（Ⅲ）） from HAC-NaAC buffer solution at 298 K by D152 resin containing -COOH function groups were presented. The sorption behaviors of D152 resin for Sm（Ⅲ） were discussed as an example. The effects of operational conditions such as pH, temperature, and contact time were studied. The statically saturated sorption capacity was 510 mg/g resin at pH 6.70 in HAc-NaAc medium at 298 K. The sorption behaviors obeyed the Freundlich isotherm. The capacity value for column study was obtained by graphical integration as 495 mg/g resin. Thomas model was applied to experimental data to predict the breakthrough curve and to determine the characteristic parameters of the column useful for process design.     

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 cetyhrimethylammonium 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.     

Microwave assisted synthesis,spectroscopic, thermal,and antifungal studies of some lanthanide（Ⅲ） complexes with a heterocyclic bishydrazone

A bishydrazone formed by the condensation of isatinmonohydrazone and salicylaldehyde reacted with lanthanide（Ⅲ） chloride to form complexes of the type [Ln（HISA）2Cl3], where, Ln=La（Ⅲ）, Ce（Ⅲ）, Pr（Ⅲ）, Nd（Ⅲ）, Sm（Ⅲ）, Eu（Ⅲ）, or Gd（Ⅲ） and HISA= [（2-hydroxybenzaldehyde）-3-isatin]bishydrazone. Both reactions were carried out under microwave conditions. The ligand and the metal complexes were characterized on the basis of elemental analysis, molar conductance, magnetic susceptibility measurements, UV visible, infrared, far infrared, and proton NMR spectral data. The ligand acted as neutral tridentate, coordinating through the carbonyl oxygen, azomethine nitrogen, and phenolic oxygen without deprotonation. The ligand and lanthanum（Ⅲ） complex were subjected to X-ray diffraction studies. The X-ray diffraction pattern of ligand exhibited its crystalline nature and that of the lanthanum（Ⅲ） complex indicated its amorphous character. The thermal decomposition behaviour of the complex, [La（HISA）2Cl3], was examined in the temperature range of 40-800 ℃ using TG, DTG, and DTA. The ligand and the metal complexes were screened for their antifungal activities.     

Synthesis and photoluminescence of a dendritic europium complex with carbazole moieties

A novel dendritic europium complex containing grafted carbazole units as functional peripheries was synthesized and characterized. The Foerster energy transfer from the peripheries of carbazole units to β-diketonate as well as from the hgands to the central Eu（Ⅲ） ions in the complex was demonstrated. Under the excitation of carbazole units and β-diketonate, characteristic red emission peaks at 612 nm with four shoulders due to the Eu（Ⅲ） ion transition of 5^D0→7^FJ （J=0-4） were observed for the complex.     

Electrochemical behavior of cerium（IV） in a RTIL and its mixture with ethanol

A systematic study was carried out to explore the electrochemical behavior of Ce in room temperature ionic liquid（CnmimBr, where n=6, 8, 10） and mixture of C6 mimBr and ethanol by cyclic voltammetry. With increase in the number of carbon atoms on the alkyl substituent on methyl imidazolium cation, the electrochemical window of the ionic liquids was found to extend towards more negative potential value, as a result there was a possibility of reduction of Ce to lower oxidation states. The diffusion coefficient and activation energy for the diffusion were calculated in all the ionic liquids and one of their mixtures with ethanol. With increase in n value, the diffusion coefficient of Ce decreased due to increase in viscosity of the medium while the activation energy for the diffusion followed a reverse trend for C6 mimBr, C8 mimBr and C10 mimBr, respectively. The observations indicated that the nature of species of Ce might be different in room temperature ionic liquids（RTILs） from that present in their mixtures with ethanol.     

罗丹明B与铁(Ⅲ)的荧光猝灭反应及其应用

在pH 10.0的NH_3-NH_4Cl缓冲溶液中,微量Fe(Ⅲ)对罗丹明B的荧光强度具有明显的猝灭作用。实验研究了该猝灭反应并讨论了将其应用于铁(Ⅲ)分析的最佳条件。实验表明,于25mL比色管中,分别依次加入3.00mL罗丹明B溶液、一定量的Fe(Ⅲ)标准溶液、2.00mL pH 10.0的NH_3-NH_4Cl缓冲溶液,用水稀释至刻度,摇匀,用1cm四面透光的石英比色皿进行测定,体系的最大发射波长λem=580nm,最大激发波长λex=550nm。Fe(Ⅲ)的质量浓度在0.004~0.028μg/mL范围内与其对应的荧光猝灭值ΔF呈良好的线性关系,相关系数为0.987 9,方法的检出限为0.003 8μg/mL。将实验体系应用于不同环境水样(矿泉水、山泉水、自来水)中Fe(Ⅲ)的测定,测得结果与原子吸收光谱法(国家水质标准方法GB 11911—1989)基本一致,相对标准偏差(RSD,n=6)为3.5%~7.5%,回收率在99%~106%之间。     

Electroanalytical tools to investigate the divalent state of Eu（III） and Nd（III） ions in non-aqueous medium

The divalent state of Ln(Ⅲ) ions has attracted much interest because of their ability to serve isomorphously in many biological sys-tem of divalent Ca(II) ion. Therefore, present paper deals with the study of divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions in non-aqueous medium. In present study, cyclic voltammetry and chronopotentiometry were utilized to establish the divalent state of Eu(Ⅲ) and Nd(Ⅲ) ions. The cy-clic voltammetric technique showed two-step reduction process at cathode for both Ln(Ⅲ) ions under specified experimental conditions and chronopotentiometric method also showed two different transition times (). Looking to the shape of cyclic voltammogram we calculated het-erogeneous forward rate constant (K0fh, cm/s) and diffusion coefficient (D, cm2/s) for both ions, which suggested that sweep rate had great ef-fect on the shape of cyclic voltammogram of Eu(Ⅲ) and Nd(Ⅲ) ions. The result of chronopotentiometry also suggested that stable divalent states of Eu(Ⅲ) and Nd(III) ions existed with chronopotentiogram with two distinct transition times. The diffusion coefficients (D, cm2/s) were calculated from Sand equation. The diffusion coefficients of both techniques were compared and the results suggested that the system at electrode surface was changing from being reversible to irreversible.     

Direct Spectroscopic Determination of Europium（ Ⅱ ） Concentration During Europium（ Ⅲ ） Electro-Reduction in Hydrochloric Acid Medium

Europiumis one of the most important rare earth(RE) element .It is widely used as a component ofcathode ray tubes , with screen coated with red phos-phor ,as phosphorescent pigments ,andinlaser optics .It can also be used as neutron-absorbing material .In…     

Synthesis and Characterization of Some Lanthanide（Ⅲ） Complexes with 4- [N-（2-methoxy benzylinine）formy1]-2, 3-dimethyl-1-phenyl-3-pyazolin-5-one

A series of seven novel lanthanide（Ⅲ ） nitrato complexes with 4-[ N-（2-methoxybenzylimine）formyl] 1-2, 3- dimethyl-1-phenyl-3-pyazolin-5-one （2mbfa）, were synthesized. These complexes were characterized by elemental analysis, molecular mass determination, conductance and magnetic moment measurements, IR, UV-visible, and ^13CNMR spectral studies, In these complexes, the Schiff base, 2mbfa, acts as neutral bidentate ligand by utilizing the carbonyl oxygen and azomethine nitrogen as donor sites. All the three nitrate ions are also coordinated unidentately with 7 coordination for the lanthanide（Ⅲ） ions with a tentative monocapped octahedral geometry for the complexes. All the seven lanthanide（Ⅲ） complexes have a general formula, [ Ln（2mbfa）：（NO3）3 ].     

2-(5-硝基-4-甲基-2-吡啶偶氮)-5-二甲氨基苯胺激光热透镜光谱法测定矿石中钯

利用He-Ne激光器,观测了2-(5-硝基-4-甲基-2-吡啶偶氮)-5-二甲氨基苯胺(5-NO₃-4-Me-PADMA)与Pd(II)形成络合物的激光热透镜效应。结果表明,在1.8mol/L H₂SO₄介质中,并在50%丙酮(体积分数,其作用是增强热透镜信号强度)存在的情况下,5-NO₃-Me-PADMA与Pd(II)反应形成蓝绿色络合物,其最大吸收峰位于623nm处,与所用He-Ne激光器输出波长632.8nm接近,据此建立了激光热透镜光谱法(TLS)测定痕量钯的新方法。实验表明,热透镜信号强度与Pd(II)质量浓度在5~250ng/mL范围内符合线性关系,相关系数为0.9989,方法检出限为1.5ng/mL。该法不仅灵敏度高,而且选择性佳,800倍量的Fe³⁺、Co²⁺和Cu²⁺,500倍量的Ni²⁺等常见金属离子以及25倍的Pt(IV),10倍量的Au(III)、Rh(III)、Ru(III)和Os(VIII),5倍量的Ir(III)等贵金属离子不干扰钯的测定。将实验方法应用于矿石中痕量钯的测定,测得结果与火焰原子吸收光谱法(FAAS)基本一致,相对标准偏差(RSD,n=6)为0.57%~1.3%。     

厌氧环境下邻菲罗啉分光光度法测定纤维水镁石中Fe(II)与Fe(III)

纤维水镁石中同时存在有不同价态的Fe即Fe(II)与Fe(III),这对开展水镁石相关研究具有重要意义。而不同价态Fe含量测定过程中存在Fe(II)在空气中易氧化成Fe(III)而导致测定不准确的问题。针对该问题,实验采用厌氧培养箱作为操作环境,对纤维水镁石的处理均在厌氧条件下进行。利用邻菲罗啉与经盐酸羟胺还原产生的总Fe(II)显色反应原理测定纤维水镁石中的总Fe,之后测定过程中不加盐酸羟胺与邻菲罗啉反应测定溶液中的Fe(II),利用总Fe与Fe(II)的差值测定Fe(III),从而实现了邻菲罗啉分光光度法对纤维水镁石中Fe(II)与Fe(III) 的准确测定。试验发现在波长为510nm,显色体系pH值为2~5,显色时间为10min条件下,Fe(II)质量浓度在0.02~5.0mg/L范围内与其吸光度符合比尔定律,校准曲线的相关系数为0.9999。采用实验方法对两个纤维水镁石样品分别进行6次平行测定,结果显示总Fe、Fe(II)及Fe(III)的相对标准偏差(RSD,n=6)均小于1%。采用电感耦合等离子体原子发射光谱法(ICP-AES)进行全Fe测定结果对照,结果表明两种方法的测定结果保持一致。     

Eu（Ⅲ） complexes involving 1,3,5-triazine diphosphine oxides

The 1,3,5-triazine diphosphine oxide ligands with donor-acceptor properties formed strong complexes with europium(III) ion in acetonitrile. Spectrophotometric titrations and mass spectra indicated that two ligands coordinated to one europium ion. The stability constants varied from 11.64 to 14.60 (log β). Binary complexes exhibited rather weak luminescence in solution. 1,3,5-triazine diphosphine oxides engaged as co-ligands in Eu(III) (2-thenoyltrifluoroacetonate)₃ complex contributed to the overall photoluminescence and allowed for excitation with longer wavelengths than the parent complex.