- Formation and dissociation kinetics of Eu(III) complexes with H5do3ap and similar dota-like ligands
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Complexation kinetics of the europium(III)-H5do3ap complex (1,4,7,10-tetraazacyclododecane-1,4,7-triacetic-10-(methylphosphonic acid)) was studied at 25 °C and I = 0.1 M KCl and compared with the analogous H4dota-like ligands. The mechanism of the formation reactions between the europium(III) ion and H3do3a, H4dota and H4dota analogs having one methylphosphonic (H5do3ap) or phosphinic acid pendant arms with a propionate side chain (H5do3apPrA) was proposed on the basis of TRLIFS measurements. The experimental data of the dissociation kinetics of the europium(III) complexes with H5do3ap and H5do3apPrA ligands show that there is no change in reactivity of the complexes due to the side chain of the phosphinic acid bifunctional chelate. The TRLIFS study of the proton-assisted decomplexation reaction of the europium(III) complexes with H3do3a, H4dota, H5do3ap and H5do3apPrA demonstrates different behaviour influenced by a change in the number of water molecules during the reaction. The advantages and disadvantages of the TRLIFS methodology as a new experimental technique for simultaneous evaluation of kinetics and reaction mechanisms are discussed.
- Táborsky, Petr,Svobodová, Ivona,Lubal, P?emysl,Hnatejko, Zbigniew,Lis, Stefan,Hermann, Petr
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- Two-photon spectroscopy of europium (III) elpasolites
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We present polarized two-photon excitation (TPE) spectra, including Zeeman data, for europium(III) in the elpasolites Cs2NaEuCl6 and Cs2NaYF6:Eu3+. Approximately 80 and 60 levels of unambiguous symmetry have been assigned respectively in each compound up to 32000 cm-1 with the aid of a one-electron crystal field Hamiltonian. This represents the most complete and extensive data set so far reported for Eu(III) at a cubic site. Comparisons are made between comparable data sets for Eu(III) f6 and Tb(III) f8. Deviations from the predictions of the one-electron crystal field model are discussed in terms of the spin correlation crystal field.
- Thorne,Jones,McCaw,Murdoch,Denning,Khaidukov
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- Influence of pH and Concentration of Complexing Agents on Fluorescence of Europium(III) Ethylenediaminetetraacetic Acid and Europium(III) Nitrilotriacetic Acid Complexes in Aqueous Solutions
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The fluorescence of aqueous solutions of Eu(III) complexes with EDTA and NTA has been investigated.Intensities of the fluorescence bands have been measured as a function of complexone concentrations in the solutions and the pH.The results are interpreted in terms of the different forms of Eu(III) complexes and their relative stabilities. - Keywords: Ethylenediaminetetraacetic acid; Europium(III) complexes; Fluorescence; Nitrilotriacetic acid
- Elbanowski, Marian,Makowska, Barbara,Lis, Stefan
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- Phase states of europium selenites in aqueous medium and in thermal analysis
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The solubility isotherm of the system Eu2O3-SeO2-H2O was studied at 100 °C. Certain amounts of the obtained selenites (normal and acid) were subjected to thermal analysis. The intermediate phases were isolated a
- Gospodinov,Stancheva
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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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- Synthesis, characterization and thermal behaviour of solid-state compounds of europium(III) and gadolinium(III) 3-methoxybenzoate
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Solid-state Ln-C8H7O3 compounds, where Ln stands for Eu(III) and Gd(III) and C8H7O3 is 3-methoxybenzoate, have been synthesized. Simultaneous thermogravimetry and differential thermal analy
- Dametto, Patricia R.,Ambrozini, Beatriz,Siqueira, Adriano B.,Carvalho, Claudio T.,Ionashiro, Massao
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- Synthesis, characterization, and luminescence properties of the ternary europium complex covalently bonded to mesoporous SBA-15
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A novel mesoporous SBA-15 type of hybrid material (phen-SBA-15) covalently bonded with 1, 10-phenanthroline (phen) ligand was synthesized by co-condensation of tetraethoxysilane (TEOS) and the chelate ligand 5-[N,N-bis-3-(triethoxysilyl)propyl]ureyl-1,10-phenanthroline (phen-Si) in the presence of Pluronic P123 surfactant as a template. The preservation of the chelate ligand structure during the hydrothermal synthesis and the surfactant extraction process was confirmed by Fourier transform infrared (FTIR) and 29Si MAS NMR spectroscopies. SBA-15 consisting of the highly luminescent ternary complex Eu(TTA)3phen (TTA = 2-thenoyltrifluoroacetone) covalently bonded to a silica-based network, which was designated as Eu-(TTA)3phen-SBA-15, was obtained by introducing the Eu(TTA) 3?·2H2O complex into the hybrid materials via a ligand exchange reaction. XRD, TEM, and N2 adsorption measurements were employed to characterize the mesostructure of Eu(TTA)3phen-SBA- 15. For comparison, SBA-15 doped with Eu(TTA)3?·2H2O and Eu(TTA)3phen complexes and SBA-15 covalently bonded with a binary europium complex with phen ligand were also synthesized, and were named SBA-15/Eu(TTA)3, SBA-15/Eu(TTA)3phen, and Eu-phen-SBA-15, respectively. The detailed luminescence studies on all the materials showed that, compared with the doping sample SBA-15/Eu(TTA)3phen and binary europium complex functionalized sample Eu-phen-SBA-15, the Eu(TTA) 3phen-SBA-15 mesoporous hybrid material exhibited higher luminescence intensity and emission quantum efficiency. Thermogravimetric analysis on Eu(TTA)3phen-SBA-15 demonstrated that the thermal stability of the lanthanide complex was evidently improved as it was covalently bonded to the mesoporous SBA-15 matrix. ? 2005 American Chemical Society.
- Peng, Chunyun,Zhang, Hongjie,Yu, Jiangbo,Meng, Qingguo,Fu, Lianshe,Li, Huanrong,Sun, Lining,Guo, Xianmin
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- Efficient red organic light-emitting devices based on a europium complex
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An efficient red organic light-emitting devices based on a europium complex were fabricated. The devices show the maximum luminance up to 800 cd/m2, an external quantum efficiency of 4.3%, current efficiency of 4.7 cd/A, and power efficiency of 1.6 lm/W. Current-voltage characteristics were also measured by using a Keithley source measurement unit. A pure red light with a peak of 612 nm and a half bandwidth of 3 nm, which is the characteristics emission of trivalent europium ion, is observed.
- Fang, Junfeng,Ma, Dongge
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- Kinetic study of the thermal decomposition of Eu3+ with β-diketone ligands and 1,10-phenanthroline or 2,2-dipyridine
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The complexes of general formula: Eu(β-dik)3L (where β-dik = 4,4,4-trifluoro-1-phenyl-1,3-butanedione (btfa), 4,4,4-trifluoro-butyryl-(+)camphor (hfc) or 2,2-dimethyl-6,6,7,7,8,8-heptafluoro-3,5-octadione (fod) and L = 1,10-phenanthroline or 2,
- Morais, Crislene R.S,Gouveia Souza, Ant?nio,Santa-Cruz, Petrus A
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- From structural properties of the EuIII complex with ethylenediaminetetra(methylenephosphonic acid) (H8EDTMP) towards biomedical applications
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Crystals of EuIII with ethylenediaminetetra(methylenephosphonic acid) (H8EDTMP) and with ethylenediaminetetraacetic acid (H 4EDTA) have been synthesized in the same experimental conditions and their X-ray analyses have been performed. The EDTMP ligand wraps the Eu III ion in a fashion similar to its carboxylic analogue, EDTA, i.e. coordinating through two nitrogen atoms and four oxygen atoms in such a way that only one oxygen atom from each phosphonate group is bonded to the central ion. The coordination sphere is completed by two oxygen atoms of the bidentate carbonate anion in the case of the EuIII-EDTMP complex, whereas the inner sphere of the EuIII-EDTA crystal is completed by three water molecules. Spectroscopic studies (UV-Vis and 31P NMR spectra) of EuIII-EDTMP solutions at controlled pH showed that the replacement of inner sphere water molecules and/or OH hydroxy groups by a carbonate anion in the EuIII-EDTMP complex at physiological pH results in the formation of [Eu(EDTMP)(CO3)]7- species which is thermodynamically stable and kinetically inert. The affinity of the carbonate anion towards the EuIII-EDTMP species was studied by analysis of f-f intensities and luminescence decay rates. The dissociation constant of the Eu III-EDTMP-carbonate complex was found to be approximately 43 mM. The presented results may be helpful in understanding the role played by the 153SmIII-EDTMP complex known as Quadramet in the seeking of metastatic tissue in bones as well as possibly giving some premises for future ligand design of these types of complexes with lanthanide radionuclides. The Royal Society of Chemistry 2006.
- Mondry, Anna,Janicki, Rafal
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- Synthesis, characterization and thermogravimetric study of the complexes [Eu(12-crown-4)·phen2]·X3 (phen=1,10-phenanthroline; X=F, Cl, Br, SCN, ClO4 and NO 3): Effect of the counter-ion on the thermal degradation profile
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The complexes [Eu(12-crown-4)·phen2]·X3 (phen = 1,10-phenanthroline; X = F, Cl, Br, SCN, ClO4 and NO 3) were synthesized and characterized by elemental analysis, UV-vis and IR spectroscopy. A thermogravimetric study was performed to evaluate the effect of the counter-ion on the thermal degradation profile of the [Eu(12-crown-4)·phen2]+3 complex cation. In general, the 1,10-phenanthroline molecules are the first to be released, showing that the crown ether molecule forms more stable bonds with the +3 cation. The fluorine complex sublimes and thus could be employed as a precursor for preparation of luminescent films.
- Belian, M?nica F.,Alves Jr., Severino,De Sá, Gilberto F.,Silva, Wagner E.,De Farias, Robson F.
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- Synthesis, potentiometric, kinetic, and NMR studies of 1,4,7,10- tetraazacyclododecane-1,7-bis(acetic acid)-4,10-bis(methylenephosphonic acid) (DO2A2P) and its complexes with Ca(II), Cu(II), Zn(II) and lanthanide(III) ions
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A cyclen-based ligand containing trans-acetate and trans- methylenephosphonate pendant groups, H6DO2A2P, was synthesized and its protonation constants (12.6, 11.43, 5.95, 6.15, 2.88, and 2.77) were determined by pH-potentiometry and 1H NMR spectroscopy. The first two protonations were shown to occur at the two macrocyclic ring N-CH 2-PO32- nitrogens while the third and fourth protonations occur at the two phosphonate groups. In parallel with protonation of the two -PO32- groups, the protons from the NH +-CH2-PO32- are transferred to the N-CH2-COO- nitrogens. The stability constants of the Ca2+, Cu2+, and Zn2+ (ML, MHL, MH2L, and M2L) complexes were determined by direct pH-potentiometry. Lanthanide(III) ions (Ln3+) form similar species, but the formation of complexes is slow; so, out-of-cell pH-potentiometry (La 3+, Eu3+, Gd3+, Y3+) and competitive spectrophotometry with Cu(II) ion (Lu3+) were used to determine the stability constants. By comparing the log KML values with those of the corresponding DOTA (H4DOTA = 1,4,7,10-tetraazacyclododecane-1,4, 7,10-tetraacetic acid) and DOTP (H8DOTP = 1,4,7,10- tetraazacyclododecane-1,4,7,10-tetramethylenephosphonic acid) complexes, the order DOTA 2+ complexes, for which the order is reversed. The relaxivity of Gd(DO2A2P) decreases between pH 2 and 7 but remains constant in the pH range of 7 1 = 3.6 mM-1 s-1). The linewiths of the 17O NMR signals of water in the absence and presence of Gd(DO2A2P) (at pH = 3.45 and 8.5) between 274 and 350 K are practically the same, characteristic of a q = 0 complex. Detailed kinetic studies of the Ce3+ and Gd3+ complexes with DO2A2P showed that complex formation is slow and involves a high stability diprotonated intermediate Ln(H2DO2A2P)*. Rearrangement of the diprotonated intermediate into the final complex is an OH- assisted process but, unlike formation of Ln(DOTA) complexes, rearrangement of Ln(H2DO2A2P)* also takes place spontaneously likely as a result of transfer of one of the protons from a ring nitrogen to a phosphonate group. The order of the OH- assisted formation rates of complexes is DOTA > DO2A2P > DOTP while the order of the proton assisted dissociation rates of the Gd3+ complexes is reversed, DOTP > DO2A2P > DOTA. 1H and 13C NMR spectra of Eu(DO2A2P) and Lu(DO2A2P) were assigned using two-dimensional correlation spectroscopy (2D COSY), heteronuclear multiple quantum coherence (HMQC), heteronuclear chemical shift correlation (HETCOR), and exchange spectroscopy (EXSY) NMR methods. Two sets of 1H NMR signals were observed for Eu(DO2A2P) characteristic of the presence of two coordination isomers in solution, a twisted square antiprism (TSAP) and a square antiprism (SAP), in the ratio of 93% and 7%, respectively. Line shape analysis of the 1H NMR spectra of Lu(DO2A2P) gave lower activation parameters compared to La(DOTP) for interconversion between coordination isomers. This indicates that the Ln(DO2A2P) complexes are less rigid probably due to the different size and spatial requirements of the carboxylate and phosphonate groups.
- Kalman, Ferenc K.,Baranyai, Zsolt,Toth, Imre,Banyai, Istvan,Kiraly, Robert,Bruecher, Ernoe,Aime, Silvio,Sun, Xiankai,Sherry, A. Dean,Kovacs, Zoltan
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- Complexation of europium(III) with 2,2′-Dipyridyl in Eu(An) 3-2,2′-dipyridyl ethyl acetate systems
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Complexation of europium(III) with 2,2′-dipyridyl in Eu(An) 3-2,2′-dipyridyl-ethyl acetate systems, where An is acetylacetonate, trichloroacetate, or trifluoroacetate ions, was studied by spectrophoto-metric methods. The stability constants of
- Smagin,Vovk,Varnavskaya,Yudina
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- Luminescent properties of yttrium diphenylphosphinate activated by europium
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The synthesis and spectroscopic characterization of yttrium diphenylphosphinates doped with europium are reported. The purity of all samples was confirmed by carbon and hydrogen micro analysis, thermal analysis, IR vibrational spectroscopy, and X-ray diff
- Francisco, Cristina S.,Stucchi, Elizabeth B.,de Abreu, Edson M.
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- Redox electrochemistry and formal standard redox potentials of the Eu(III)/Eu(II) redox couple in an equimolar mixture of molten NaCl-KCl
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The electrochemical redox process Eu(III)+e-?Eu(II) in an equimolar NaCl-KCl melt in the temperature range 973-1123 K on glassy carbon electrodes was studied by linear sweep voltammetry, cyclic voltammetry, chronopotentiometry and reversal chronopotentiometry. It was determined that at a sweep rate of ν≤0.1 V s-1, the electroreduction of Eu(III) to Eu(II) is reversible, but at 0.1-1, mixed diffusion and electron-transfer control is observed. Further increase of polarization rate, ν>0.5 V s-1 results in electron-transfer control. The diffusion coefficients of Eu(III) and Eu(II) were determined by linear sweep voltammetry and chronopotentiometry methods. The values found by these methods are in a good agreement with each other. The diffusion coefficients of Eu(III) and Eu(II) in the NaCl-KCl melt are discussed in connection with the strength and stability of these complex ions. The standard rate constants for the reduction of Eu(III) to Eu(II) were calculated on the basis of cyclic voltammetry data. The sluggish kinetics of this reaction is discussed in terms of substantial rearrangement of the europium coordination sphere. The formal standard redox potentials of EEu(III)/Eu(II)* were determined from linear sweep voltammetry and cyclic voltammetry.
- Kuznetsov,Gaune-Escard
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- Low-temperature heat capacity and thermodynamic properties of crystalline [Re2(Ala)4(H2O)8] (ClO4)6 (Re = Eu, Er; Ala = alanine)
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[Re2(Ala)4(H2O)8] (ClO4)6 (Re = Eu, Er; Ala = alanine) were synthesized, and the low-temperature heat capacities of the two complexes were measured with a high-precision adiabatic calorimeter over the temperature range from 80 to 370 K. For [Eu2(Ala)4(H2O)8] (ClO4)6, two solid-solid phase transitions were found, one in the temperature range from 234.403 to 249.960 K, with peak temperature 243.050 K, the other in the range from 249.960 to 278.881 K, with peak temperature 270.155 K. For [Er2(Ala)4(H2O)8] (ClO4)6, one solid-solid phase transition was observed in the range from 270.696 to 282.156 K, with peak temperature 278.970 K. The molar enthalpy increments, ΔHm, and entropy increments, ΔSm, of these phase transitions, were determined to be 455.6 J mol-1, 1.87 J K-1 mol-1 at 243.050 K; 2277 J mol-1, 8.43 J K-1 mol-1 at 270.155 K for [Eu2(Ala)4(H2O)8] (ClO4)6; and 4442 J mol-1, 15.92 J K-1 mol-1 at 278.970 K for [Er2(Ala)4(H2O)8] (ClO4)6. Thermal decompositions of the two complexes were investigated by use of the thermogravimetric (TG) analysis. A possible mechanism for the thermal decomposition is suggested.
- Liu, Beiping,Tan, Zhi-Cheng,Zhang, Dashun,Nan, Zhaodong,Sun, Lixian,Xu, Fen,Lan, Xiaozhen,Liang, Ping,Yu, Xiaomei
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- Photoluminescence of Ba(SCN)2:Eu2+
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The luminescence properties of Eu2+ in the novel host lattice Ba(SCN)2 has been investigated. At low temperature a strong green emission is observed with a maximum at 511nm, which is strongly quenched with increasing temperatures. The excitation spectrum yielded a Stokes shift which clearly shows the presence of a 5d → 4f emission. The quenching behaviour can be explained by the fact that the lowest 5d state is located at slightly lower energy than the conduction band of the host lattice. At increasing temperature thermal occupation of the conduction band occurs followed by nonradiatively excitonic relaxation to the ground state. The luminescence properties of Ba(SCN)2:Eu2+ are very similar to those of Sr(SCN)2:Eu2+.
- Wickleder, Claudia
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- Synthesis, bright luminescence and crystal structure of a novel neutral europium complex
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A novel organic ligand, 6-diphenylamine carbonyl 2-pyridine carboxylic acid, and the corresponding europium complex, tris(6-diphenylamine carbonyl 2-pyridine carboxylato) europium(III) (Eu-DPAP) have been designed and synthesized. The crystal structure and photoluminescence of Eu-DPAP complex have been studied. The results showed that Eu-DPAP is an electroneutral complex that emits very strong red fluorescence. The lifetime of 5Do of Eu3+ in the complex solid was examined using time-resolved spectroscopy, and the value for crystalline Eu(DPAP)3 · 12H2O is 0.69 ± 0.01 ms.
- An, Bao-Li,Gong, Meng-Lian,Zhang, Ji-Ming,Zheng, Shao-Liang
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- An efficient bonding-type Eu-containing copolymer as red phosphor applied in LED
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A luminescent europium-containing copolymer, poly(MMA- UA -co-Eu (DBM) 2 (TOPO)2)was synthesized The copolymer was characterized by FT-IR, UV-vis, gel permeation chromatograph (GPC), ICP, thermogravimetric analysis (TGA), derivative thermal gravimetric analysis (DTG) and differential scanning calorimetry (DSC). The Eu-copolymer phosphor exhibited high thermal stability, high glass transition, excellent photoluminescence properties (PL), appropriate CIE chromaticity coordinates for red and good quantum yield (18%) under near-UV light excitation. An intense red-emitting light-emitting diode (LED) was fabricated by combining poly[UA-MMA-co-Eu (DBM)2(TOPO) 2] with a 395 nm-emitting InGaN chip. The results indicate that the Eu-copolymer phosphor may act as a red component for fabrication of white LEDs. Crown Copyright
- Yan, Haigang,Wang, Huihui,He, Pei,Shi, Jianxin,Gong, Menglian
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- Structural and spectroscopic investigations of the EuIII-CDTA system
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Two crystal structures of EuIII complexes with CDTA (trans-1,2-diaminocyclohexane-N,N,N′,N′-tetraacetate), [C(NH2)3]3[Eu2(CDTA)2(H2O)2]ClO4 · 7H2O (I) and [C(NH2)3][Eu(CDTA)(H2O)] · 2.375H2O (II), are presented. Both structures are polymeric and the central metal ions are eight-coordinate. The first coordination sphere of each EuIII cation contains five carboxylate oxygen atoms, two nitrogen ones and a water molecule. For I, as well as for water solutions of the EuIII-CDTA complex at various pH values, the spectroscopic (UV-Vis) properties were investigated.
- Janicki, Rafa?,Mondry, Anna,Starynowicz, Przemys?aw
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- Synthesis and photoluminescence properties of novel europium complexes of 2′-hydroxyacetophenone and 4,6-diacetylresorcinol
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Novel europium (III) complexes of the formulae Eu(OHAP)3·2H2O, Eu(OHAP)3Phen, Eu2(DAR)3·4H2O and Eu2(DAR)3Phen2 (HOHAP = 2′-hydroxyacetophenone, H2DAR = 4,6-diacetylresorcinol, Phen = 1,10-phenanthroline) have been designed and synthesized in this paper. These complexes were characterized by elemental analysis, FT-IR, and UV-vis. Based on these observations, the ligands are coordinated to Eu(III) via the acetyl and phenolic oxygens, and H2DAR is concluded to be bis-bidentate donor. Photoluminescence studies showed that the several complexes emitted red luminescence. Thermo-gravimetric analysis showed that the complexes possess good thermal stability. Also, it was found that Phen as a synergic ligand, coordinated to Eu(III) in a composite system like 2′-hydroxyacetophenone and 4,6-diacetylresorcinol, could enhance the complexes luminescence intensity, quantum yield and lifetime.
- Liu, Sheng-Li,Wen, Chun-Lin,Qi, Su-Su,Liang, En-Xiang
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- Synthesis and bright luminescence of lanthanide (Eu(III), Tb(III)) complexes sensitized with a novel organic ligand
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A novel organic ligand, 6-[(benzylamino) carbonyl]-2-pyridine carboxylic acid (HBAP), and the corresponding lanthanide complexes, tris(6-[(benzylamino) carbonyl]- 2-pyridine carboxylato) lanthanide(III) (Ln-BAP, Ln=Eu, Tb, Gd), have been designed and synthesized. The lanthanide (Eu(III), Tb(III)) complexes were efficiently sensitized by BAP ligand. The fluorescence quantum yields were investigated by comparison with a luminescence standard, and the yields were 15±3%, 34±3% for the solid europium and terbium complexes respectively. The lowest triplet level of HBAP ligand was calculated from the phosphorescence spectrum of Gd-BAP complex, and the energy transfer mechanisms in the lanthanide complexes were discussed.
- An, Bao-Li,Gong, Meng-Lian,Cheah, Kok-Wai,Zhang, Ji-Ming,Li, King-Fai
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- Synthesis and luminescent properties of gadolinium aluminates phosphors
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In this work, aluminum-gadolinium oxides with different phases were prepared by the non-hydrolytic sol-gel route, using lower temperatures than those employed in methods such as solid-state reaction and Pechini method. The influence of heating treatment on sample structure was investigated. The formation process and the local structure of the samples are discussed on the basis of thermal, X-ray diffraction, photoluminescence (PL) spectroscopy, and infrared spectroscopy analyses. The quantum efficiency of Eu3+ in the different phases obtained in this studied was evaluated. Initial crystallization and the GdAlO3 phase were observed at temperatures around 400 °C. PL data of all the samples revealed the characteristic transition bands arising from the 5D0 → 5FJ (J = 0, 1, 2, 3, and 4) manifolds under maximum excitation at 275, 393, and 467 nm in all cases. The 5D0 → 7F2 transition often dominates the emission spectra, indicating that the Eu3+ ion occupies a site without inversion center.
- Matos, Marcela G.,Calefi, Paulo S.,Ciuffi, Katia J.,Nassar, Eduardo J.
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- Photoacoustic and luminescence spectra study on the effects of chlorine substituent on the energy transfer of Eu(III)-chlorobenzoic acid
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The photoacoustic (PA) amplitude spectra of three complexes of Eu(III) combined with chlorobenzoic acid (Eu(o-ClC6H4CO2)3·H2O, Eu(m-ClC6H4CO2)3·H2/sub
- Hu, Bin,Chen, Da,Su, Qingde
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- Structural and spectroscopic investigations of europium(III) entrapped by the ethylenediaminetetra(methylenephosphonate) ligand in K12H8[Eu4(EDTMP)4] · 45H2O crystal
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The X-ray crystal structure of an anionic octacoordinate Eu3+ complex of the formula K12H8[Eu4(EDTMP)4] · 45H2O, where EDTMP is the ethylenediaminetetra(methylenephosphonate) anion, hereina
- Janicki, Rafa?,Mondry, Anna
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- Kinetics of formation and dissociation of lanthanide(III) complexes with the 13-membered macrocyclic ligand TRITA
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The tetraazamacrocyclic ligand TRITA4- is intermediate in size between the widely studied and medically used 12-membered DOTA4- and the 14-membered TETA4-. The kinetic inertness of GdTRITA- was characterized by the rates of exchange reactions with Zn2+ and Eu3+. In the Zn2+ exchange, a second order [H+] dependence was found for the pseudo-first-order rate constant (k0 = (4.2 ± 0.5) × 10-7 s-1; k′ = (3.5 ± 0.3) × 10-1 M-1S-1, k″ = (1.4 ±0.4) × 103 M-2s-1)- In the Eu3+ exchange, at pH 2+ species. At physiological pH, the kinetic inertness of GdTRITA- is considerably lower than that of GdDOTA- (t1/2 = 444 h (25°C) vs. 3.8 × 105 h (37°C), respectively). However, GdTRITA - is still kinetically more inert than GdDTPA2-, the most commonly used MRI contrast agent (t1/2 = 127 h). The formation reactions of LnTRITA- complexes (Ln = Ce, Gd and Yb) proceed via the rapid formation of a diprotonated intermediate and its subsequent deprotonation and rearrangement in a slow, OH- catalyzed process. The stability of the LnH2TRITA* intermediates (log KLnH2L* = 3.1-3.9) is lower than that of the DOTA-analogues. The rate constants of the OH- catalyzed step increase with decreasing lanthanide ion size, and are about twice as high as for DOTA-complexes. The Royal Society of Chemistry 2005.
- Balogh, Edina,Tripier, Raphael,Ruloff, Robert,Toth, Eva
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- In situ synthesis and luminescence characteristics of complexes of europium(III) with 4,6-diacetylresorcinol
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The complexes of europium(III) with 4,6-diacetylresorcinol (H2DAR) and a co-ligand (phen, bpy or 2,2′-bipyridine N,N′-dioxide (2,2′-bpyO2)) were in situ synthesized in silica matrix via a two-step gel process. The formation of complexes in silica gel was confirmed by the luminescence excitation spectra. The silica gels that contain in situ synthesized europium complexes exhibit the characteristic emission bands of the Eu(III). The results show that there are two ways to enhance the emission intensity of the Eu(III): (i) synthesize the complex in silica matrix and (ii) synthesize the complex with a co-ligand, which coordinates with Eu(III) in the composite system and can efficiently transfer the energy from 4,6-diacetylresorcinol to the Eu(III). The order of the luminescence intensities of the complexes is: Eu2(DAR)3(phen)2-(sol-gel) > Eu2(DAR)3(2,2′-bpyO2)2-(sol-gel) > Eu2(DAR)3 (bpy)2-(sol-gel) > Eu2(DAR)3-(sol-gel) > pure Eu2(DAR)3·4H2O.
- Liu, Sheng-Li,Wen, Chun-Lin,Chen, Chun,Qi, Su-Su,Liang, En-Xiang
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- MOESSBAUER SPECTROSCOPY STUDY OF AN ANHYDROUS NON-STOICHIOMETRIC EUROPIUM(III) CHLORIDE PHASE.
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Anhydrous europium(III) chloride, when heated under vacuum at temperatures above 570 K, decomposes according to the overall reaction. A nonstoichiometric chlorine-deficient phase with the hexagonal UCl//3-type structure is observed down to at least a europium-to-chlorine ratio of 1:2. 84. Samples of composition EuCl// greater than //2//. //8 were examined by Moessbauer spectroscopy, X-ray diffraction, and electrical conductivity techniques. The temperature dependent Moessbauer spectra provide, for the first time, evidence for electron exchange between neighboring europium sites in a nonstoichiometric europium compound. Chemical isomer shifts and ratios of recoil-free fractions (Lamb-Moessbauer factors) for europium(II) to europium(III) are also derived from the spectra. Lattice parameters obtained from X-ray data are discussed in relation to those for the stoichiometric EuCl//3//. //0//0 phase.
- Ball,Jenden,Lyle,Westall
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- Study of the annealing temperature effect on the structural and luminescent properties of SrWO4:Eu phosphors prepared by a non-hydrolytic sol-gel process
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In this paper, we investigate the influence of temperature on the structural and luminescent properties of Eu3+-doped strontium tungstate oxide (SrWO4) prepared by the non-hydrolytic sol-gel route. X-ray diffraction (XRD) analyses showed that the SrWO4:Eu scheelite type structure was formed in a unique phase at 900 and 1000 °C over 2 h. Raman spectra indicated only one type of [WO4] tetrahedron. The optical properties were investigated by ultraviolet-visible (UV-vis) absorption spectroscopy and photoluminescence (PL) measurements at room and liquid N 2 temperatures. PL study showed 5D0 → 7F2 electric dipole transition is dominant when Eu 3+ occupies a non-centrosymmetric environment. The (FEG-SEM) images indicated that an increase in the annealing temperature contributed to the coalescence process which promoted the growth of aggregated particles of a polydisperse nature. A qualitative analysis of the powders obtained by dispersive X-ray detector (EDS) indicated that the samples are composed of Sr, W and O while Eu3+ ion was not observed due to it low concentration.
- Pereira,De Moura,Nogueira,Lima,Longo,De Sousa Filho,Serra,Nassar,Rosa
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Read Online
- Thermal and spectroscopic studies on solid Ketoprofen of lighter trivalent lanthanides
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Solid-state Ln(L)3 compounds, where Ln stands for trivalent La, Ce, Pr, Nd, Sm, Eu, and L is ketoprofen have been synthesized. Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction powder (DRX) patterns, Fourier transformed infrared spectroscopy (FTIR), and other methods ofanalysis were used to study solid Ketoprofen of lighter trivalent lanth anides. The results provided information of the composition, dehydration, coordination mode, structure, thermal behavior, and thermal decomposition. The theoretical and experimental spectroscopic study suggests that the carboxylate group of ketoprofen is coordinate to metals as bidentatebond.
- Galico, D. A.,Holanda, B. B.,Perpetuo, G. L.,Schnitzler, E.,Treu-Filho, O.,Bannach, G.
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p. 371 - 380
(2012/04/23)
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- Synthesis, thermal properties and spectroscopic study of solid mandelate of light trivalent lanthanides
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Characterization, thermal stability and thermal decomposition of light trivalent lanthanide mandelates Ln(C6H5CH(OH)CO 2)3·nH2O (Ln = La to Gd, except Pm) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), experimental and theoretical infrared spectroscopy, elemental analysis, X-ray diffractometry, complexometry and TG-DSC coupled to FTIR. The dehydration of the lanthanum, samarium, europium and gadolinium compounds occurs in a single step while for praseodymium and neodymium ones it occurs in two consecutive steps. The thermal decomposition of the anhydrous compounds occurs in three, four or five consecutive steps, with formation of the respective oxides CeO2, Pr6O11 and Ln2O3 (Ln = La, Nd to Gd) as final residues. The results also provide information concerning the composition, thermal behavior and gaseous products evolved during the thermal decomposition of these compounds. The theoretical and experimental spectroscopic data suggest the possible modes of coordination of the ligand with the lanthanum.
- Gigante,Gomes,Lima,Caires,Treu-Filho,Ionashiro
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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 light trivalent lanthanides folates on solid state
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Solid state Ln2-L3 compounds, where Ln stands for light trivalent lanthanides (lanthanum to gadolinium), except promethium, and L is folate (C19H17N7O6), have been synthesized. Simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry, infrared spectroscopy (FTIR), TG coupled to FTIR, elemental analysis and complexometry were used to characterize and to study the thermal behaviour of these compounds. The results provided information concerning the stoichiometry, crystallinity, ligand's denticity, thermal stability, thermal behaviour and identification of the gaseous products evolved during the thermal decomposition of these compounds.
- Dametto, P. R.,Caires, F. J.,Ambrozini, B.,Ionashiro, M.
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p. 831 - 836
(2011/11/04)
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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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- Synthesis, characterization and thermal behaviour of solid-state compounds of light trivalent lanthanide succinates
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Characterization, thermal stability and thermal decomposition of light trivalent lanthanide succinates, Ln2(C4H4O4)3 ·nH2O (Ln = La to Gd, except Pm) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), infrared spectroscopy, TG-FTIR system, elemental analysis and complexometry. The dehydration of the lanthanum and cerium compounds occurs in a single step, while for the praseodymium to gadolinium compounds the dehydration occurs in two consecutive steps. The thermal decomposition of the anhydrous compounds occurs in consecutive and/or overlapping steps, except for the cerium compound, with formation of the respective oxides, CeO2, Pr6O11 and Ln2O3 (Ln = La, Nd to Gd), as final residue. The results also provided information concerning the denticity of the ligand and thermal behaviour of these compounds.
- Lima,Caires,Carvalho,Siqueira,Ionashiro
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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 behavior on solid tartrates of light trivalent lanthanides
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Solid state Ln-L compounds, where Ln stands for light trivalent lanthanides (L-Gd) and L is tartrate, have been synthesized. Thermogravimetry and differential thermal analysis (TG/DTA), differential scanning calorimetry (DSC), X-ray powder diffractometry,
- Ambrozini,Dametto,Siqueira,Carvalho,Ionashiro
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p. 761 - 764
(2010/01/05)
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- Macrocyclic receptor exhibiting unprecedented selectivity for light lanthanides
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We report a new macrocyclic ligand, N,N'-bis[(6-carboxy-2-pyridil)methyl]- 4,13-diaza-18-crown- 6 (H2bp18c6), designed for complexation of lanthanide ions in aqueous solution. Potentiometric measurements evidence an unprecedented selectivity of bp18c6 for the large LnIIIions. Among the different LnIII ions, LaIII and CeIII show the highest log KML values, with a dramatic drop of the stability observed from CeIII to LuIII asthe ionic radius of the LnIII ions decreases (log Cel- log KLul ) 6.9). The X-ray crystal structures of the GdIII and YbIII complexes show that the metal ion is directly bound to the10 donor atoms of the bp18c6 ligand. The structure of the complexes in solution has been investigated by 1H and 13C NMR spectroscopy, as well a s by theoretical calculations performed at the DFT (B3LYP) level. Our results indicate that a conformational change occurs around the middle of the lanthanide series: for the larger LnIII ions the most stable conformation is Δ( δ λδ)( δ λδ), while for the smallest LnIII ions (Gd-Lu) our calculations predict the Δ(λδ λ)( λδ λ form being the most stable one. This structural change was confirmed by the analysis of the Ce III-, PrIII-, and YbIII-induced paramagnetic 1H shifts. The selectivity that bp18c6 shows for the large LnIII ions can be attributed to a better fit between the light LnIII ions and the relatively large crown fragment of the ligand. Indeed, our DFT calculations indicate that the interaction between the LnIII ion and several donor atoms of the crown moiety is weakened as the ionic radius of the metal ion decreases.
- Roca-Sabio, Adrian,Mato-Iglesias, Marta,Esteban-Gomez, David,Toth, Eva,Blas, Andres de,et al.
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p. 3331 - 3341
(2009/07/30)
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- Stability, water exchange, and anion binding studies on lanthanide(III) complexes with a macrocyclic ligand based on 1.7-diaza-12-crown-4: Extremely fast water exchange on the Gd3+ complex
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The picolinate-derivative ligand based on the 1,7-diaza-12-crown-4 platform (bp12c4 2-) forms stable Ln3+ complexes with stability constants increasing from the early to the middle lanthanides, then being relatively constant for the
- Palinkas, Zoltan,Roca-Sabio, Adrian,Mato-lglesias, Marta,Esteban-Gomez, David,Platas-Iglesias, Carlos,De Blas, Andres,Rodriguez-Blas, Teresa,Toth, Eva
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p. 8878 - 8889
(2009/12/25)
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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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- 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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- 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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- 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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- Synthesis, Characterization and thermal behaviour of hemimellitic acid complexes with lanthanides(III)
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The complexes of lanthanides(III) with hemimellitic acid (1,2,3-benzenetricarboxylic acid, H3btc) of the formula Ln(btc)?nH2O, where Ln=lanthanide(III) ion and n=2-6 were prepared and characterized by elemental analysis, infrared spe
- Lyszczek
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p. 595 - 599
(2008/10/09)
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- Comparison of thermal properties of lanthanide trimellitates prepared by different methods
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By diffusion in gel medium new complexes of formulae: Nd(btc) ·6H2O, Gd(btc)·4.5H2O and Er(btc)?5H2O (where btc=(C6H3(COO)33-) were obtained. Isomorphous compounds were crystallized in the
- Lyszczek, Renata
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p. 833 - 838
(2009/02/07)
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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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- Preparation and characterization of the lanthanide complex Eu(TTA) 3phen / vinyl pyrrolidone luminescent nanofiber by electrospinning
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Eu(TTA)3phen/vinyl pyrrolidone (PVP) composite nanofibers have been prepared by electrospinning technique. The spectral properties of Eu(TTA)3phen/PVP composite nanofibers have been studied, as compared to that of Eu(TTA)3phen powders. The excitation of Eu(TTA) 3phen/PVP systems by UV light results in a ligand-to-metal energy transfer and the emission spectra display characteristic luminescence of the central ions (5D0→7F2 for Eu3+). Photoluminescence measurements show that Eu(TTA) 3phen/PVP nanofibers have higher intensity and longer lifetime than that of Eu(TTA)3phen powders because of the influence of PVP on the coordinative environment of lanthanide ions.
- Wei, Liu,Ce, Wang
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p. 1951 - 1954
(2008/03/17)
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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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- Thermal and spectroscopic investigations of new lanthanide complexes with 1,2,4-benzenetricarboxylic acid
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The new 1,2,4-benzenetricarboxylates of lanthanide(III) of the formula Ln(btc)?nH2O, where btc is 1,2,4-benzenetricarboxylate; Ln is La-Lu, and n=2 for Ce; n=3 for La, Yb, Lu; and n=4 for Pr-Tm were prepared and characterized by elemental analy
- Lyszczek
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p. 533 - 539
(2008/10/09)
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- Multi-Functional Copolymers Comprising Rare Earth Metal Complexes and Devices Thereof
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The invention relates to copolymer complexes of the formula (I): wherein [Ax-[B(C)]y-Dz] denotes a single unit of the copolymer complex that is repeated n times, wherein n is an integer greater than one, and wherein the single unit comprises a conjugated backbone coordinated to a complex (C) comprising rare earth metal(s); x, y and z are numbers greater than zero such that x=y+z; A is independently selected from a group consisting of: fluorene, carbazole, oxadiazole, triphenylamine or derivatives thereof; B is a functional ligand selected from the group consisting of: benzoic acid, 1,3-diphenylpropane-1,3-dione, 1,10-phenanthroline, 2,2-bipyridine, or derivatives thereof; and D is independently selected from a group consisting of: fluorene, carbazole, oxadiazole, triphenylamine or derivatives thereof.
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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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- 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, thermal stability, reactivity, and antimicrobial properties of some novel lanthanide(III) complexes of 2-(N-salicylideneamino)-3-carboxyethyl-4,5,6,7-tetrahydrobenzo[b]thiophene
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Two series of new lanthanide(III) complexes of the type [Ln(HSAT) 2(H2O)3Cl3] and [Ln(HSAT) 2(NO3)3], where Ln = La, Pr, Nd, Sm, Eu, Gd, Dy, Tm, Yb, or Lu, and HSAT = 2-(N-salicy
- Mohanan,Devi
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p. 600 - 609
(2008/10/09)
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- Extraction of lanthanide chlorides by binary extractants based on phosphinic acid derivatives
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The extraction of lanthanide chlorides by methyltrioctylammonium dialkylphosphinate, dialkyl-monothiophosphinate, or dialkyldithiophosphinate in toluene was studied. In all cases, extractable MA3 compounds were formed in an organic phase. The extractability of metals increased in the order La a considerable effect on the distribution of the lanthanide salts. The extraction capacity of the binary extradants toward lanthanum chloride decreased in the order methyltrioctylammonium dialkylphosphinate > methyltrioctylammonium dialkylmonothiophosphinate > methyltrioctylammonium dialkyldithiophosphinate. Copyright
- Egorova,Belova,Voshkin,Zhilov,Khol'kin
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p. 1781 - 1784
(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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- Effect of solid matrices on the luminescence of europium(III) tungstate
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The effect of natural and synthetic zeolites, CaCO3, and crystalline zirconium phosphate on the luminescence intensity of europium tungstate sorbates was studied in comparison to europium(III)-doped Mg, Ca, Sr, Ba, La, Gd, and Y tungstates prepared by coprecipitation with tungstate anion. The effects of the alkaline-earth cation, metal salt anion, coprecipitation conditions, and calcination temperature on the luminescence were revealed. X-ray powder diffraction showed that the resulting compounds have a scheelite structure. The luminescence intensity of Eu(III)-doped Ca tungstate under the identical conditions of short-wave excitation (λex = 254 nm) makes up 33% of the intensity exhibited by the commercial FL-612 red-emitting phosphor.
- Topilova,Meshkova,Dotsenko,Kovalevskaya,Kiriyak,Malinka,Efryushina
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p. 1932 - 1935
(2008/10/09)
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