- TEMPERATURE-DEPENDENT ENERGY TRANSFER FROM 5D 3 AND 5D4 STATES OF TB3 + TO SM3 + .
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The present study deals with the interaction of **5D//3 and **5D//4 states of Tb**3** plus when Sm **3** plus ions are incorporated in a LaCl//3 matrix. A dipole-dipole interaction mechanism is suggested for the transfer of energy from **5D//3 and **5D//4 states of Tb**3** plus to Sm**3** plus . Temperature-dependent study reveals multiphonon relaxation of the LaCl//3 matrix.
- Kandpal,Joshi
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- Preparation of metallic terbium and terbium hydride
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The conditions of the reaction between TbCl3 and LiH were optimized. The resultant terbium hydride was used to obtain metallic terbium by vacuum thermolysis.
- Kamarzin,Osadchaya,Sokolov,Trushnikova,Zubareva,Saprykin,Troitskii
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- Luminescence property of the terbium bipyridyl complex incorporated in silica matrix by a sol-gel method
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Silica-based composite materials incorporated with a terbium bipyridyl complex, SiO2:Tb(bpy)23+, were prepared by a sol-gel method. The thermal stability of Tb(bpy)23+ was improved by incorporation into the silica matrix, and its green emission lines were intensified by heat-treatments under appropriate temperature conditions. These results demonstrate that the composite materials such as SiO2:Tb(bby)23+ possess potential as efficient phosphors.
- Jin,Tsutsumi,Deguchi,Machida,Adachi
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- Raman and X-ray diffraction studies of terbium trichloride: Phase characterization and temperature relationship
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We have used phonon Raman spectrophotometry as a rapid and convenient tool, complimentary to X-ray diffraction, for investigating the polymorphism of TbCl3. In the literature one finds references to the polymorphism of TbCl3, but there is some confusion regarding the structural identity and temperature relationship of the different phases reported. In the present work TbCl3 was prepared via reaction of Tb4O7 and anhydrous HCl gas. Its Raman spectrum was acquired at room temperature and pressure (RTF) and correlated with the results of X-ray diffraction analysis to confirm the PuBr3-type orthorhombic structure. This TbCl3 structure was then monitored as a function of temperature, including after being quenched from the molten state. From our Raman and X-ray results, a phase transition occurred at about 510°C to a tentatively assigned tetragonal structure, which appeared stable up to the melting point (582°C). Additional annealing studies down to about 250°C resulted in the observation of only the RTF form. No evidence for a UCl3-type hexagonal or AlCl3-type monoclinic structure was found in this work, though they are common forms of other lanthanide trichlorides.
- Morrison, Henry G.,Assefa, Zerihun,Haire, Richard G.,Peterson, Joseph R.
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- Hydrothermal synthesis and luminescent properties of LuBO3: Tb3+ microflowers
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Hexagonal vaterite-type LuBO3:Tb3+ microflower-like phosphors have been successfully prepared by an efficient surfactant- and template-free hydrothermal process directly without further sintering treatment. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrometry, transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence (PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples. The as-obtained phosphor samples present flowerlike agglomerates composed of nanoflakes with thickness of 40 nm and high crystallinity in spite of the moderate reaction temperature of 200°C. The reaction mechanism has been considered as a dissolution/precipitation mechanism; the self-assembly evolution process has been proposed on homocentric layer-by-layer growth style. Under ultraviolet excitation into the 4J8→ 4f7d transition of Tb3+ at 248 nm (or 288 nm) and low-voltage electron beam excitation, LuBO3:Tb3+ samples show the characteristic green emission of Tb3+ corresponding to 5D4 → 7F6,5,4,3 transitions with the 5D 4 → 7F5 transition (542 nm) being the most prominent group, which have potential applications in fluorescent lamps and field emission displays.
- Yang, Jun,Zhang, Cuimiao,Wang, Lili,Hou, Zhiyao,Huang, Shanshan,Lian, Hongzhou,Lin, Jun
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- Enhanced photoluminescence of GdPO4:Tb3+ under VUV excitation by controlling ZnO content and annealing temperature
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High-quality Zn-free and added GdPO4:Tb3 green phosphors, i.e., fine size as well as smooth and spherical morphologies, were synthesized by ultrasonic spray pyrolysis. The influence of Zn2+ content and annealing temperatur
- Park,Heo
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- X-RAY POWDER DIFFRACTION STUDY OF THE CHLORIDE-BROMIDE SYSTEMS OF TRIVALENT GADOLINIUM, TERBIUM, AND YTTERBIUM.
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The lanthanoid mixed halide systems, MCl//3-MBr//3, for M equals Gd, Tb, and Yb, have been prepared by mixing and fusing the pure reactants and have been examined by X-ray powder diffraction procedures. For M equals Gd, UCl//3, (P6//3/m)-, PuBr//3 (Cmcm)-
- Olejak-Chodan, Monika,Lasocha, Wieslaw,Eick, Harry A.
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- Electrochemiluminescence of terbium (III)-two fluoroquinolones-sodium sulfite system in aqueous solution
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The electrochemiluminescence (ECL) of Tb3+-enoxacin-Na2SO3 system (ENX system) and Tb3+-ofloxacin-Na2SO3 system (OFLX system) in aqueous solution is reported. ECL is generated by the oxidation of Na2SO3, which is enhanced by Tb3+-fluoroquinolone (FQ) complex. The ECL intensity peak versus potential corresponds to oxidation of Na2SO3, and the ECL emission spectra (the peaks are at 490, 545, 585 and 620 nm) match the characteristic emission spectrum of Tb3+, indicating that the emission is from the excited state of Tb3+. The mechanism of ECL is proposed and the difference of ECL intensity between ENX system and OFLX system is explained. Conditions for ECL emission were optimized. The linear range of ECL intensity versus concentrations of pharmaceuticals is 2.0 × 10-10-8.0 × 10-7 mol l-1 for ENX and 6.0 × 10-10-6.0 × 10-7 mol l-1 for OFLX, respectively. A theoretical limit of detection is 5.4 × 10-11 mol l-1 for ENX and 1.6 × 10-10 mol l-1 for OFLX, respectively. The ECL was satisfactorily applied to the determination of the two FQs in dosage form and urine sample.
- Chen, Shi-lv,Ding, Fen,Liu, Yu,Zhao, Hui-chun
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- Synthesis, structure and photoluminescence of novel lanthanide (Tb(III), Gd(III)) complexes with 6-diphenylamine carbonyl 2-pyridine carboxylate
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A novel organic ligand, 6-diphenylamine carbonyl 2-pyridine carboxylic acid (HDPAP), and the corresponding lanthanide complexes, tris(6-diphenylamine carbonyl 2-pyridine carboxylato) terbium(III) (Tb-DPAP) and tris(6-diphenylamine carbonyl 2-pyridine carboxylato) gadolinium(III) (Gd-DPAP) have been designed and synthesized. The crystal structure and photoluminescence of Tb-DPAP and Gd-DPAP have been studied. The results showed that the lanthanide complexes have electroneutral structures, and the solid terbium complex emits characteristic green fluorescence of Tb(III) ions at room temperature while the gadolinium complex emits the DPAP ligand phosphorescence. The lowest triplet level of DPAP ligand was calculated from the phosphorescence spectrum of Gd-DPAP in N,N-dimethyl formamide (DMF) dilute solution determined at 77K, and the energy transfer mechanisms in the lanthanide complexes were discussed. The lifetimes of the 5D4 levels of Tb 3+ ions in the terbium complex were examined using time-resolved spectroscopy, and the values are 0.0153 ± 0.0001ms for solid Tb(DPAP)3 · 11.5H2O and 0.074 ± 0.007ms for 2.5 × 10-5mol/l Tb-DPAP ethanol solution.
- An, Bao-Li,Gong, Meng-Lian,Cheah, Kok-Wai,Wong, Wai-Kwok,Zhang, Ji-Ming
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- Ligand-sensitized fluorescence of Tb3+ in Tb3+-dibutylphosphate complexes: Application for the estimation of DBP
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The fluorescence of Tb3+ is sensitized by complexation with dibutylphosphate (DBP) and tri-n-butylphosphate (TBP). The excitation maximum for the Tb3+-DBP complex occurs at 218.5 nm, while that for the Tb3+-TBP complex is observed at 228.0 nm. Both complexes yield Tb3+ fluorescence at 548 nm. The difference in the excitation maxima for the two complexes has been used to advantage for the estimation of DBP in the presence of TBP. DBP is the main degradation product of TBP in the PUREX process and the method described in this work can thus serve as a useful analytical tool in monitoring the quality of the TBP in the process. This method has been shown to be applicable for the estimation of DBP when present to an extent of 0.1-10% of TBP, in TBP/dodecane solutions.
- Maji,Viswanathan
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- Energy transfer from Gd3+ to Tb3+ in solution
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The use of the 4f7 ion Gd3+ as an energy transfer donor in solution is reported for the first time. The luminescence from the 6P multiplet term of Gd3+ in chloride solution is quenched not only by increasing concentration, but also by the addition of Tb3+. The energy transfer from Gd3+ to Tb3+ in solution has been followed by selective decay measurements and the energy transfer constant shows a linear relationship with Tb3+ concentration up to ～0.05 M, after which value saturation is reached. The Tb3+ acceptor 5D4 emission intensity as a function of time is well-modeled.
- Tanner, Peter A.,Wang, Jiwei
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- Observations on photochemical fluorescence enhancement of the terbium(III)-sparfloxacin system
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Fluorescence of terbium(III) was sensitized when excited in the presence of sparfloxacin (SPFX) in the aqueous solution because a Tb(III)-SPFX complex was formed. The sensitized fluorescence was further enhanced when this system was exposed to 365 nm ultraviolet light. By the spectral properties and contrast experiments, it is proved that irradiation makes this system undergo photochemical reactions and a new terbium complex which is more favorable to the intramolecular energy transfer is formed. The mechanism of photochemical fluorescence enhancement of the Tb(III)-SPFX system is discussed and a new sensitive and selective photochemical fluorimetry for the determination of SPFX is established. Under the optimum conditions, the linear range is 1.0-50 × 10-7 M for SPFX, the detection limit is 3.0 × 10-9 M and the R.S.D. for 5.0 × 10-7 M SPFX is 1.3% (n = 9). Without any pretreatment the recovery of SPFX in human urine was determined with satisfaction.
- Fangtian, You,Tieli, Zhang,Linpei, Jin,Huichun, Zhao,Shubin, Wang
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- Thermodynamics of lanthanide elements. III. Molar enthalpies of formation of Tb3+(aq), Ho3+(aq), Yb3+(aq), Yb2+(aq), TbBr3(cr), HoBr3(cr), and YbBr3(cr) at 298.15 K
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Enthalpies of solution of high-purity terbium, holmium, and ytterbium metals and of the corresponding tribromides in aqueous hydrochloric acid of various molalities lead to the following standard molar enthalpies of formation ΔfHm0/(kJ * mol-1) at 298.15 K: Tb3+(aq), -(698.3+/-1.5); Ho3+(aq), -(707.2+/-2.4); Yb3+(aq), -(670.5+/-2.7); Yb2+(aq), -(530.4+/-3.3); TbBr3(cr), -(839.1+/-2.4); HoBr3(cr), -(842.1+/-2.7); YbBr3(cr), -(793.8+/-2.4).A value of -(1.06+/-0.05) V is deduced from the above results for the standard potential of the reaction: Yb3+ + 1/2H2 = Yb2+ + H+, through the use of suitable entropy values.These results are discussed and compared with previous experimental or assessed values.
- Bettonville, S.,Goudiakas, J.,Fuger, J.
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- THERMAL AND MAGNETIC PROPERTIES OF TbCl//3.
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The specific heat of polycrystalline TbCl//3 was measured in the temperature range 1. 65 K less than T less than 100 K. Magnetization and susceptibility of TbCl//3 were determined on polycrystalline and single crystal samples between 1. 7 K less than T less than 350 K. Our experimental data show ferromagnetic order of TbCl//3 below T//c equals (3. 65 plus or minus 0. 03) K. The magnetic entropy S//m//a//g lost during ordering as calculated from the specific heat nearly corresponds to ln 2 indicating the ordering of a S equals one-half magnetic system. In the ordered state the magnetic moment orients along the crystallographic alpha -axis. The saturation moment is (8. 1 plus or minus 0. 1) mu //B. The critical parameters S//m//a//g(T//c) and T//c/ theta are determined and compared with theoretical calculations for 3D-Ising magnets. Our results are in best agreement with a previous neutron investigation performed by Murasik et al.
- Kremer, R.,Gmelin, E.,Simon, A.
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- Comparison of covalency in the lanthanide chloride and nitrate complexes based on the adsorption data on zeolite y
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The changes of the distribution constants Kd of lanthanide chlorides in the system: zeolite Y (solid phase)-sodium chloride (aqueous phase) were investigated. The evident tetrad effect in the change of log Kd values within the lantha
- G?adysz-P?aska, Agnieszka,Majdan, Marek,Ferenc, Wies?awa,Sarzyński, Jan
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p. 469 - 474
(2012/03/22)
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- Preparation and characterization of rare earth orthoborates, LnBO 3 (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y) and LaBO3:Gd, Tb, Eu by metathesis reaction: ESR of LaBO3:Gd and luminescence of LaBO3:Tb, Eu
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Lanthanide orthoborates of composition LnBO3 (Ln = Tb, La, Pr, Nd, Sm, Eu, Gd, Dy, Y) and LaBO3:Gd, Tb, Eu have been prepared by metathesis reaction. This method provides a convenient route for the synthesis of orthoborates and its solid solutions at low temperatures. Powder X-ray diffraction and FT-IR spectroscopy were used to characterize these borates. Rare earth borates, (LnBO3) are isomorphous with different forms of CaCO3 depending on the radius of rare earth ion. LaBO3, LaBO3:Gd, Tb, Eu, PrBO3, NdBO3 crystallized in aragonite structure, SmBO3 crystallized in H-form and TbBO 3, EuBO3, GdBO3, DyBO3, YBO 3 crystallized in vaterite structure. The structural analysis of TbBO3 was carried out. The morphology of these borates was obtained from Scanning electron microscopy. Spin-Hamiltonian parameters for Gd 3+ are deduced from room temperature electron spin resonance spectrum of LaBO3:Gd. The luminescence of LaBO3:Tb, Eu gave characteristics peaks corresponding to Tb3+, Eu3+ respectively.
- Velchuri, Radha,Kumar, B. Vijaya,Devi, V. Rama,Prasad,Prakash, D. Jaya,Vithal
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p. 1219 - 1226
(2011/07/09)
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- Lanthanide carbonates
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The crystal and molecular structures of the rare earth carbonates with the general formulae [C(NH2)]3 [Ln(CO3)4 (H2O)]·2H2O (where Ln = Pr3+,Nd 3+,Sm3+,Eu3+,Gd3+,Tb 3+)and [C(NH2)]3 [Ln(CO3) 4]·2H2O (where Ln = Y3+,Dy 3+,Ho3+,Er3+, Tm3+,Yb 3+,Lu3+) were determined. The crystals consist of monomeric [Ln(CO3)4 (H2O)] 5-or [Ln(CO3)4] 5-complex anions in which the carbonate ligands coordinate to the Ln3+ion in a bidentate manner. The spectroscopic (UV/Vis/NIR and IR) properties of the crystalline lanthanide carbonates, as well as their aqueous solutions, were determined. Correlation between the spectroscopic and the structural data enabled us to conclude that the [Ln(CO3)4 (OH)]6-and [Ln-(CO 3)4]5- species predominate in the light and heavy lanthanide solutions, respectively. The nature of the Ln-O interaction was also discussed. The experimental data, as well as the theoretical calculations, indicated that the Ln-O(CO3 2-) bond is more covalent than the Ln-O(OH2) bond. Moreover, the covalency degree is larger for the heavy lanthanide ions. Inspection of the NBO results revealed that the oxygen hybrids, with the approximate composition sp4, form strongly polarized bonds with the 6s6p5d4 hybrids of lutetium. 2011 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
- Janicki, Rafal,Starynowicz, Przemyslaw,Mondry, Anna
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p. 3601 - 3616
(2011/10/11)
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- Synthesis, characterization and thermal behaviour of solid-state tartrates of heavy trivalent lanthanides and yttrium(III)
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Solid state Ln2-L3 compounds, where Ln stands for heavy trivalent lanthanides (terbium to lutetium) and yttrium, and L is tartrate [(C4H4O6)-2] have been synthesized. Simultaneous thermogra
- Ambrozini, B.,Dametto, P. R.,Ionashiro, M.
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p. 867 - 871
(2011/10/31)
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- Structural characterization of methanol substituted lanthanum halides
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The first study into the alcohol solvation of lanthanum halide [LaX3] derivatives as a means to lower the processing temperature for the production of the LaBr3 scintillators was undertaken using methanol (MeOH). Initially the de-hydration of {[La(μ-Br)(H2O)7](Br)2}2 (1) was investigated through the simple room temperature dissolution of 1 in MeOH. The mixed solvate monomeric [La(H2O)7(MeOH)2](Br)3 (2) compound was isolated where the La metal center retains its original 9-coordination through the binding of two additional MeOH solvents but necessitates the transfer of the innersphere Br to the outersphere. In an attempt to in situ dry the reaction mixture of 1 in MeOH over CaH2, crystals of [Ca(MeOH)6](Br)2 (3) were isolated. Compound 1 dissolved in MeOH at reflux temperatures led to the isolation of an unusual arrangement identified as the salt derivative {[LaBr2.75·5.25(MeOH)]+0.25 [LaBr3.25·4.75(MeOH)]-0.25} (4). The fully substituted species was ultimately isolated through the dissolution of dried LaBr3 in MeOH forming the 8-coordinated [LaBr3(MeOH)5] (5) complex. It was determined that the concentration of the crystallization solution directed the structure isolated (4 concentrated; 5 dilute) The other LaX3 derivatives were isolated as [(MeOH)4(Cl)2La(μ-Cl)]2 (6) and [La(MeOH)9](I)3·MeOH (7). Beryllium Dome XRD analysis indicated that the bulk material for 5 appear to have multiple solvated species, 6 is consistent with the single crystal, and 7 was too broad to elucidate structural aspects. Multinuclear NMR (139La) indicated that these compounds do not retain their structure in MeOD. TGA/DTA data revealed that the de-solvation temperatures of the MeOH derivatives 4-6 were slightly higher in comparison to their hydrated counterparts.
- Boyle, Timothy J.,Ottley, Leigh Anna M.,Alam, Todd M.,Rodriguez, Mark A.,Yang, Pin,Mcintyre, Sarah K.
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p. 1784 - 1795
(2010/07/03)
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- Synthesis, characterization and thermal behaviour of heavy lanthanide and yttrium pyruvates in the solid state
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Solid-state Ln-L compounds, where Ln stands for heavy trivalent lanthanides or yttrium (III) (Tb-Lu, Y) and where L is pyruvate, have been synthesized. Thermogravimetry and derivative thermogravimetry (TG/DTG), differential scanning calorimetry (DSC), X-R
- Siqueira,De Carvalho,Rodrigues,Ionashiro,Bannach,Ionashiro
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- Synthesis, characterization and thermal behaviour of solid-state 3-methoxybenzoates of heavy trivalent lanthanides and yttrium(III)
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Solid-state Ln(L)3 compounds, where Ln stands for trivalent Tb, Dy, Ho, Er, Tm, Yb, Lu and Y, and L is 3-methoxybenzoate, have been synthesized. X-ray powder diffractometry, infrared spectroscopy, complexometry and elemental analysis were used to characterize the compounds. Inorder to study the thermal behaviour of these compounds simultaneous th ermogravimetry and differential thermal analysis (TG-DTA) and differential scanning calorimetry (DSC) were used. The results provided information on the composition, dehydration, polymorphic transformation, thermal stability and thermal decomposition of the synthesized compounds.
- Dametto, P. R.,Ambrozini, B.,Siqueira, A. B.,Carvalho, C. T.,Ionashiro, M.
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p. 933 - 940
(2011/01/06)
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- Construction and photoluminescence of monophase hybrid materials derived from a urea-based bis-silylated bipyridine
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A urea-based bis-silylated bipyridine ligand derived from 4,4′-diamino-2,2′-bipyridine has been prepared. Organic-inorganic hybrid materials with a high loading of lanthanide 2,2-bipyridine moieties were obtained by using the silylated bipyridine as the o
- Li, Huanrong,Lin, Nana,Wang, Yige,Feng, Yu,Gan, Quanying,Zhang, Hongjie,Dong, Qinglin,Chen, Yuhuan
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p. 519 - 523
(2009/05/09)
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- Electrogenerated luminescence of chosen lanthanide complexes at stationary oxide-covered aluminium electrode
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The electrochemiluminescence (ECL) of aqueous solutions of Tb3+, Dy3+, and Eu3+ complexes having a variety of ligand groups was studied using an oxide-covered aluminium electrode. The ligand groups, under study, were the aromatic acids (salicylic, phthalic), the chelatic ligands (ethylenediamine dl(o-hydroxy-phenylacetic acid), EDDHA and ethylenediamine tetraacetic acid, EDTA), as well as Schiff bases: 1,10-disalicylidene-4,7-diaza-1,10-decyldiamine and 2-salicylideneamine-2-hydroxymethyl-1,3-propanediol. The results show that the generated emissions were mainly the result of energy transfer from the ligands to the metals. The best ECL properties were observed in the case of the complexes Tb(III)-EDDHA, Dy(III)-EDDHA, and Dy(III)-salicylic acid. In the ternary systems: Schiff base-Tb(III)-Eu(III) energy transfer to the emitting level of the Eu(III) ion was observed.
- Staninski, Krzysztof,Lis, Stefan
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- Solubility behavior of rare earths with ammonium carbonate and ammonium carbonate plus ammonium hydroxide: Precipitation of their peroxicarbonates
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The purpose of this work is to report the significant behavior of the rare earths when treated with ammonium carbonate and with a binary mixture of ammonium carbonate plus ammonium hydroxide. The carbonates of some rare earths are completely soluble in ammonium carbonate or in ammonium carbonate plus ammonium hydroxide, while others are only partially soluble and finally some are completely insoluble. Addition of hydrogen peroxide to the soluble complexed rare earth carbonates results in the precipitation of a series of a new compounds described as rare earth peroxicarbonates. The rare earths have some different precipitation behavior in the carbonate-peroxide system. Some are completely and immediately precipitated, others are completely precipitated after an aging period, and finally other are not precipitated at all. These different behaviors open a new possibility for the separation chemistry of the rare earths. Sm, Gd, Dy, Y, Yb and Tm are fast and completely soluble in ammonium carbonate. Ho, Eu and Tb are completely soluble in ammonium carbonate but slowly dissolved. La, Ce, Pr and Nd are only partially soluble in ammonium carbonate. While Ce, Pr, Nd, Sm, Eu and Dy are completely and easily soluble in the ammonium carbonate plus ammonium hydroxide mixture, La is only partially soluble and Tb is completely insoluble in the same mixture. Concerning the peroxicarbonates, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy and Ho are quantitatively precipitated. The precipitation of the Er peroxicarbonate is quantitative, but after an aging period of 24 h. Y is not precipitated at all. The process is very easy, simple and economically attractive. Although proved in bench scale, its scale-up is easily feasible.
- de Vasconcellos, Mari E.,da Rocha,Pedreira,Queiroz, Carlos A. da S.,Abr?o, Alcídio
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p. 426 - 428
(2008/10/09)
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- 2-Methoxybenzylidenepyruvatewith heavier trivalent lanthanides and yttrium(III): Synthesis and characterization
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Solid-state Ln(2-MeO-BP) compounds, where Ln stands for trivalent Eu to Lu and Y(III) and 2-MeO-BP (which is 2-methoxybenzylidenepyruvate) have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanni
- Ionashiro,Bannach,Siqueira,De Carvalho,Rodrigues,Ionashiro
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p. 953 - 959
(2009/02/01)
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- Synthesis, characterization and thermal behaviour of solid 2-methoxybenzoates of trivalent metals
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Solid-state Ln(L)3 compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and L is 2-methoxybenzoate have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanni
- Siqueira,Carvalho,Ionashiro,Bannach,Rodrigues,Ionashiro
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p. 945 - 951
(2009/02/01)
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- A systemic study of stepwise chlorination-chemical vapor transport characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by alkaline chlorides as complex former
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A systematic study has been carried out for the stepwise chlorination-chemical vapor transport (SC-CVT) characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes KLnCl4 and NaLnCl4 (Ln = Sc, Y and La-Lu) used NaCl and KCl as complex former, respectively. The results showed that the SC-CVT characteristics are similarly for NaCl and KCl as complex former, the main deposition temperature of the rare earth chlorides LnCl3 is in the increasing order ScCl3 3 3, and then with a systematically decreasing trend from the early lanthanide chlorides to the end one. The results also showed that the total transported amount of the produced chlorides is YCl3 > ScCl3, and they are much higher than that of most lanthanoid chlorides. For lanthanoids, the total transported amount of chloride increases systematically from the early lanthanoid chlorides to the end one except for EuCl3 and GdCl3 mediated by KCl and NaCl as complex former, respectively, which showed the divergence effect of Gd in the total transport efficiency. But there are some differences in SC-CVT characteristics of pure rare earth oxide mediated by KCl and NaCl as complex former, that is the main deposition temperature region for the same rare earth element was lower for KCl than that for NaCl as complex former except for LaCl3, CeCl3, YbCl3 and LuCl3, while the total transport amount of rare earth chloride for KCl as complex former is higher than that for NaCl except for LaCl3 and EuCl3. More over, the discussion was carried out for Sc and Y on the one hand and the lanthanides contain 4f electron as another hand based on the 4f electron hybridization assumption. Further more, the transport characteristics of rare earth oxides with alkaline chlorides as complex former in this study were compared to that with AlCl3 as complex former.
- Sun, Yan-Hui,He, Peng,Chen, Hua-Ni
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p. 352 - 358
(2008/10/09)
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- Microcalorimetric studies on the interactions of lanthanide ions with bovine serum albumin
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The interactions of lanthanide ions (Ln3+) with bovine serum albumin (BSA) under mimetic physiological conditions (310.15 K, pH 6.7, 0.1MNaCl) were studied by microcalorimetry. For the first time, based on Two Sets of Independent Sites Model, m
- Li,Wang,Li,Wang
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p. 899 - 905
(2008/10/09)
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- Synthesis, characterization and thermal behaviour of solid-state compounds of yttrium and lanthanide benzoates
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Solid-state Ln(Bz)3?H2O compounds where Ln stands for trivalent yttrium or lanthanides and Bz is benzoate have been synthesized. Simultaneous thermogravimetry-differential thermal analysis (TG-DTA), X-ray powder diffractometry, infra
- Locatelli,Rodrigues,Siqueira,Ionashiro,Bannach,Ionashiro
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p. 737 - 746
(2008/10/09)
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- Equilibria and structure of the lanthanide(III)-2-hydroxy-1,3- diaminopropane-N,N,N′,N′-tetraacetate complexes: Formation of alkoxo-bridged dimers in solid state and solution
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The complex formed between 1,3-diamino-2-hydroxypropane-N,N,N′, N′-tetraacetic acid (H4L-OH) and Nd3+ at pH 7.5 was found to be a dinuclear dimer in the solid state by X-ray crystallography. In the complex K4[Nd2(L-O)2-(H2O) 2]-14H2O each ligand is coordinated to both Nd 3+ atoms with an iminodiacetate group (the Nd3+-Nd 3+ distance is 3.9283(8) A). The alcoholic OH groups are deprotonated, and the alkoxo oxygens are coordinated to both Nd3+ in a bridging position. The Nd3+ ions are nine-coordinated with one water molecule per Nd(III) ion in the inner sphere. The complex K 4[Nd2(L-O)2(H2O)2] ·14H2O has an inversion center, and the space group is P1. Two of the K+ counterions are six-coordinated, while the other two K+ ions are eight-coordinated; polar polymeric water-K+ layers are formed between the apolar ligand layers via the bridging water molecules. The dinuclear dimer complexes are also present in aqueous solution. The proton relaxivities of the Gd3+ complex decrease with the increase of pH, and at pH > 6, the low relaxivity values indicate the probable absence of H2O in the inner sphere and the predominance of the eight-coordinated dimer species [Gd2(L-O)2]. 4- The results of ESI-TOF MS studies of the complexes of La 3+, Nd3+, and Lu3+ proved the formation of dinuclear dimers in dilute (0.25 mM) solutions. pH-potentiometric titrations indicate the formation of complexes with 1:1 (Ln(L-OH)-, Ln(HL-OH), and Ln2(L-O)24-) and 2:1 (Ln 2(L-O)+) metal-to-ligand ratios. The stability constants of the Ln(L-OH)- species increase from La3+ (log K = 10.19) to Lu3+ (log K = 14.08). The alcoholic OH group of the Ln(L-OH)- species dissociates at unusually low pH values. The pH range of dissociation shifts to lower and lower pH's with the increasing atomic number of the lanthanides. This pH range is about 4-7 for the La3+ complex and 1-4 for the Lu3+ complex. The results of 1D and 2D 1H and 13C NMR studies of the La3+ complex, the number and multiplicity of signals, and the values of coupling constants are in agreement with the dinuclear dimer structure of the complex in solution.
- Tircso, Gyula,Benyei, Attila,Bruecher, Erno,Kis, Anita,Kiraly, Robert
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p. 4951 - 4962
(2008/10/09)
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- Synthesis, characterization and thermal behaviour of solid 4-methoxybenzoates of heavier trivalent lanthanides
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Solid-state Ln-4-MeO-Bz compounds, where Ln stands for trivalent Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu and Y and 4-MeO-Bz is 4-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scan
- Rodrigues, Emanuel C.,Siqueira, Adriano B.,Ionashiro, Elias Y.,Bannach, Gilbert,Ionashiro, Massao
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p. 149 - 155
(2008/10/09)
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- Synthesis, characterization and thermal studies on solid compounds of 2-chlorobenzylidenepyruvate of heavier trivalent lanthanides and yttrium(III)
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Solid-state compounds of general formula LnL3· nH 2O, where Ln represents heavier lanthanides and yttrium and L is 2-chlorobenzylidenepyruvate, have been synthesized. Chemical analysis, simultaneous thermogravimetry-differential anal
- Bannach,Schnitzler,Treu Filho,Utuni,Ionashiro
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p. 233 - 240
(2008/10/09)
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- Lanthanide contraction and pH value controlled structural change in a series of rare earth complexes with p-aminobenzoic acid
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A series of rare earth complexes with p-aminobenzoic acid (HL) have been synthesized: [RE2L6(H2O)2] n [RE=La (1), Ce(2), Pr(3), Sm(4), Eu(5), Tb(6), Dy(7), Er(9)] and [RE2L6(H2O)4]·2H 2O [RE=Tb(6′), Ho(8), Yb(10), Lu(11), Y(12)]. The crystal structures of 1, 2, 6, 6′, 7, 9 and 12 have been determined and the isomorphous relationships of the others have been identified. Their structures change from two-dimensional (2D) array (the coordination number of the metal ions is nine for 1 and eight for 2-7 and 9) to double-nuclear structure (the metal ions are eight-coordinated) for 6′, 8 and 10-12, as controlled by lanthanide contraction. The structural type has been found influenced by the pH value of the reaction mixtures.
- Sun, Hao-Ling,Ye, Chao-Hong,Wang, Xin-Yi,Li, Jun-Ran,Gao, Song,Yu, Kai-Bei
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- Fullerides: Heterometallic superconductors with composition M2M′C60 (M = K, Rb; M′ = Yb, Lu, Sc)
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One- or two-step reactions of potassium and rubidium fullerides with composition Mk C60 (M = K, Rb; k = 3-6) and K 6C60 + m K mixtures (m = 1, 3) with anhydrous salts M′Cl3 (M′ = La, Pr, Nd, Sm, Gd, Tb, Yb, Lu, Y, Sc) and YbI2 in a toluene-THF medium afforded heterometallic fullerides M3- n M′n C60 (n = 1-3). Among these compounds, substituted fullerides with composition M2M′C60 (M′ = Yb, Lu, Sc) display superconducting properties with critical temperatures of 14-20 K.
- Bulychev,Lunin,Kul'bachinskii,Shpanchenko,Privalov
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p. 1686 - 1692
(2007/10/03)
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- Cooperative Yb3+-Tb3+ dimer excitations and upconversion in Cs3Tb2Br9:Yb3+
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Green Tb3+5D4→7FJ luminescence visible by eye is observed under near-infrared laser excitation. Optical spectroscopic techniques including absorption, luminescence, and excitation spectroscopy are used to characterize this upconversion (UC) luminescence. The Tb3+ UC luminescence is present for all temperatures within a range from 10 to 300 K, and gains intensity by three orders of magnitude between 10 and 300 K. For T ≥ 100 K the dominant upconversion mechanism is the cooperative sensitization of Tb3+ by two Yb3+ ions. In this temperature regime the Tb3+ UC luminescence dominates the visible (VIS) spectrum for all near-infrared (NIR) excitations, resulting in the characteristic green luminescence. At 10 K, the color of the luminescence changes from green to blue, depending on the excitation wavelength corresponding to the dominance of Tb3+ UC luminescence or the Yb3+-Yb3+ cooperative pair luminescence. Two color excitation spectroscopy is performed to directly observe an excited state absorption (ESA) step in the Tb3+ UC luminescence excitation spectrum at 10 K. This allows the unambiguous assignment of a type of ground state absorption/excited state absorption (GSA/ESA) mechanism responsible for the upconversion in this system at 10 K. We explain this cooperative interaction in the framework of an Yb3+-Tb3+ exchange-coupled dimer. An energy level diagram for this dimer is presented. Excitation into dimer levels around 12000-14500 cm-1, where neither Yb3+ nor Tb3+ single ions have levels, leads to Yb3+ luminescence at 10 K. For laser excitation, 53 W/mm2, resonant with an ESA transition a VIS/NIR photon ratio of 2.7(10)-5 is found at 10 K.
- Salley, G. M.,Valiente, R.,Guedel, H. U.
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- Stepwise chlorination-chemical vapor transport reaction for rare earth oxide mixtures Gd2O3-Tb4O7, Tb4O7-Dy2O3 and Dy2O3-Ho2O3
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Stepwise chlorination-chemical vapor transport (SC-CVT) reaction has been investigated for the rare earth oxide mixtures Gd2O3-Tb4O7, Tb4O7-Dy2O3 and Dy2O3-Ho2O3 mediated by vapor complexes LnAlnCl3n+3 (where Ln=rare earth elements). The results show selective deposition of lighter elements at higher temperatures. The separation factors are 5.84 for Gd/Tb, 3.72 for Tb/Dy and 3.13 for Ho/Dy when using CO as the CVT carrier gas. A combination of enhanced separation factor with reduced total transport yield is also observed for the Tb4O7-Dy2O3 system when using argon as the CVT carrier gas.
- Sun, Yan-Hui,Zhang, Li-Qing,Lei, Peng-Xiang,Wang, Zhi-Chang,Guo, Lei
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p. 196 - 199
(2008/10/08)
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- Synthesis, characterisation and thermal behaviour of solid stat compounds of 4-methylbenzylidenepyruvate with heavier trivalent lanthanides and yttrium(III)
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Solid state Ln-4-Me-BP compounds, where Ln stands for heavier trivalent lanthanides (gadolinium to lutetium) and yttrium(III) and 4-Me-BP is 4-methylbenzylidenepyruvate (CH3-C6H4-CH=CH-COCOO-), have been synthesized. Eleme
- Marques,Melios,Ionashiro
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p. 145 - 150
(2008/10/08)
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- Comparative study for stepwise chlorination-chemical vapor transport characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes LnAlnCl3n+3
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A systematic study has been carried out for the stepwise chlorination-chemical vapor transport (SC-CVT) characteristics of pure rare earth oxides from Sc2O3 to Lu2O3 mediated by the vapor complexes LnAlnCl3n+3 (where Ln = rare earth elements) under identical conditions. The results show that the total transported amount of the produced chlorides is the highest for YCl3; it is also high for ScCl3, but low for LaCl3, and then increases systematically from the early lanthanide chlorides to the end lanthanide chlorides except CeCl3, EuCl3 and GdCl3. The results also show that the main deposition temperature of the chlorides is in the increasing order ScCl3 3 3 and then with a systematically decreasing trend from the early lanthanide chlorides to the end lanthanide chlorides. Based on the literature data for the solid complexes LnAl3Cl12 and LnAl3Br12, a similar coordination structure assumption is introduced for the vapor complexes LnAl3Cl3n+3 from Ln = Sc to Ln = Lu with the same stoichiometry to explain the SC-CVT characteristics of the pure rare earth oxides from Sc2O3 to Lu2O3 using a 4f electron hybridization assumption.
- Wang, Zhi-Chang,Sun, Yan-Hui,Guo, Lei
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p. 109 - 113
(2008/10/08)
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- Synthesis, characterization and anticoagulant action of lanthanide complexes of warfarin
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Thirteen lanthanide complexes of warfarin, LnL3·nH2O [n = 6 (Ln = La-Yb) or n = 4 (Ln = Y); L = (C19H15O4)-] have been synthesized and characterized by elemental analyses, IR, 1H
- Jiao, Tian Quan,Wu, Ji Gui,Zeng, Fu Li,Fu, Yun Long,Deng, Ru Wen
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p. 725 - 735
(2008/10/09)
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- Solution enthalpies of hydrates LnCl3·xH2O (Ln=Ce-Lu)
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Trichlorides of the lanthanide elements Ln=Ce-Lu form: (a) isotypic hexahydrates LnCl3·6H2O with a coordination number (CN) 8 for the Ln3+ ions. (b) Two isotypic groups of trihydrates LnCl3·3H2O, in the first group Ln=Ce-Dy the CN is 8; the structure of the second group Ln=Er-Lu is unknown. With Ho no trihydrate exists; a dihydrate is formed. (c) Two isotypic groups of monohydrates LnCl3·H2O with unknown structure - Ln=Ce-Dy and Ln=Ho-Lu. For all compounds and for anhydrous chlorides LnCl3 solution enthalpies were measured with an isoperibolic calorimeter. The ΔsolH0 values do not depend only on the difference (lattice enthalpies/hydration enthalpies), but also on the state in solution. According to Spedding the CN of the Ln3+ ions against water changes from 9 to 8 between Nd and Sm, causing minima in the series of solution enthalpies. Dihydrates LnCl3·2H2O are found for Ln=Ce, Pr, Nd, Sm and presumably for Eu and Gd. They are not yet well characterised.
- Seifert,Funke
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- The dehydration schemes of rare-earth chlorides
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The dehydration schemes of LaCl3·7H2O, CeCl3·7H2O, PrCl3·7H2O, PrCl3·7H2O, EuCl3·6H2O, GdCl3·OH2O, HoCl3·6H2O, ErCl3·OH2O, TmCl3·6H2O, YbCl3·OH2O and YCl3·6H2O have been investigated by the isothermal fluidizedbed technique. This technique is based on the fact that reactions proceed at a close approach to equilibrium and thus give rise to constant reaction rate regimes at constant gas flow and temperature in the bed. By injecting a small portion of HCl(g) (～1%) into the gas stream, hydrolysis is avoided, and dehydration to the monohydrate is recorded by both thermal analysis of the preheated inlet gas and chemical analysis of samples taken from the bed. Based on the present results, together with previous results on NdCl3·OH2O, TbCl3·6H2O and DyCl3·6H2O, dehydration schemes of all rare-earth chlorides except LuCl3 and ScCl3 are suggested.
- Hong, Vu Van,Sundstroem, Johan
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- Thermal decomposition of rare earth complexes with 2-amino-3,5-dichlorobenzoic acid
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The conditions of the thermal decomposition of the 2-amino-3,5-dichloro-benzoates of Y and lanthanides have been studied. During heating in air, the dihydrated complexes Ln(C6H2Cl2NH2COO) 3·2H2/
- Mrozek,Sikorska,Rzaczynska
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p. 707 - 720
(2008/10/09)
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- Thermodynamic Properties of the Rare Earth Element Vapor Complexes LnAl3Cl12 from Ln = La to Ln = Lu
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Systematic analysis of rare earth element complexes has been carefully carried out in the liquid and solid states but not in the gaseous state because of the lack of a complete set of experimental data for any kind of vapor complexes of all rare earth elements. Here we present experimental quenching results which suggest that the LnAl3Cl12 complexes are the predominant vapor complexes roughly in the temperature range 588-851 K and pressure range 0.01-0.22 MPa for all of the 14 rare earth elements Ln = La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu. For these elements, thermodynamic functions of the reactions LnCl3(s) + 3/2Al2Cl6(g) = LnAl3Cl12(g) were calculated from the measurements. Those for the radioelement Pm were smoothly interpolated. The results show Gd divergences from the standard enthalpies and standard entropies from LaAl3Cl12 to LuAl3Cl12.
- Wang, Zhi-Chang,Wang, Lin-Shan
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p. 1536 - 1540
(2008/10/09)
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- Investigation of the kinetics of the fluidized bed process for the dehydration of NdCl3·6H2O, TbCl3·6H2O and DyCl3·6H2O
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Dehydration of NdCl3·6H2O, TbCl3·6H2O and DyCl3·6H2O was carried out by fluidization in a gas mixture of Ar and HCl. In a series of isothermal experiments the effect of different process parameters was considered. Water vapour pressure of gas leaving the fluidized bed was estimated by using a simple mass balance. It was shown that the rate-limiting step of the overall dehydration process in the fluidized bed is removal of water vapour by a saturated bulk gas flow. However, the saturated gas phase data could not be thermodynamically interpreted. The reason to this is discussed.
- Sundstroem, Johan,Van Hong, Vu
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- Lanthanide Ion Chelates of Dibenzyl 1,1'-Diacetylferrocenebis(hydrazonatocarbodithioate)
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A new ligand, dibenzyl 1,1'-diacetylferrocenebis(hydrazonatocarbodithioate), Fe[C5H4C(CH3)=NNHCSSCH2C6H5)2] (H2Dafhb) and its chelates with lanthanide ions, Ln(Dafhb)Cl (Ln = lanthanide) have been prepared by the reaction of the H2Dafhb with LnCl3. All compounds were characterized by elemental analyses, IR, (1H) NMR, UV, electrolytic conductivity and TGA measurements. It is shown that the ligand coordinates to the metal in the thiol form and that one chloride ion participates in coordination. The chelates are non-electrolytes in DMF and are more thermostable than the ligand due to formation of chelate rings.
- Gang, Zhao,Yuan, Cao
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p. 1207 - 1217
(2008/10/09)
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- Polymorphism of TbCl3
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3 different modifications of TbCl3 were synthesized.TbCl3 (UCl3-type), probably in a metastable state, crystallizes in space group P63/m with a = 737.63(2) pm, c = 405.71(2) pm and Z = 2.TbCl3 (PuBr3-type) crystallizes in space group Cmcm with a = 384.71(6) pm, b = 1177.37(7) pm, c = 851.77(4) pm and Z = 4. h-TbCl3, the high temperature phase being stable above 790 K, crystallizes in space group P42/mnm with a = 642.51(4) pm, c = 1177.14(18) pm and Z = 4. - Keywords: Temperature Polymorphism, Trirutile Structure, Lanthanoid Trichlorides, MAPLE
- Gunsilius, Harald,Borrmann, Horst,Simon, Arndt,Urland, Werner
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p. 1023 - 1028
(2007/10/02)
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