10025-76-0Relevant articles and documents
Formation and dissociation kinetics of Eu(III) complexes with H5do3ap and similar dota-like ligands
Táborsky, Petr,Svobodová, Ivona,Lubal, P?emysl,Hnatejko, Zbigniew,Lis, Stefan,Hermann, Petr
, p. 4119 - 4130 (2007)
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.
Influence of pH and Concentration of Complexing Agents on Fluorescence of Europium(III) Ethylenediaminetetraacetic Acid and Europium(III) Nitrilotriacetic Acid Complexes in Aqueous Solutions
Elbanowski, Marian,Makowska, Barbara,Lis, Stefan
, p. 907 - 914 (1982)
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
Construction and photoluminescence of monophase hybrid materials derived from a urea-based bis-silylated bipyridine
Li, Huanrong,Lin, Nana,Wang, Yige,Feng, Yu,Gan, Quanying,Zhang, Hongjie,Dong, Qinglin,Chen, Yuhuan
, p. 519 - 523 (2009)
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
Synthesis, characterization and thermal behaviour of solid-state compounds of europium(III) and gadolinium(III) 3-methoxybenzoate
Dametto, Patricia R.,Ambrozini, Beatriz,Siqueira, Adriano B.,Carvalho, Claudio T.,Ionashiro, Massao
, p. 765 - 768 (2009)
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
Efficient red organic light-emitting devices based on a europium complex
Fang, Junfeng,Ma, Dongge
, p. 4041 - 4043 (2003)
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.
From structural properties of the EuIII complex with ethylenediaminetetra(methylenephosphonic acid) (H8EDTMP) towards biomedical applications
Mondry, Anna,Janicki, Rafal
, p. 4702 - 4710 (2006)
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.
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
Belian, M?nica F.,Alves Jr., Severino,De Sá, Gilberto F.,Silva, Wagner E.,De Farias, Robson F.
, p. 59 - 61 (2005)
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.
Complexation of europium(III) with 2,2′-Dipyridyl in Eu(An) 3-2,2′-dipyridyl ethyl acetate systems
Smagin,Vovk,Varnavskaya,Yudina
, p. 367 - 372 (2012)
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
Redox electrochemistry and formal standard redox potentials of the Eu(III)/Eu(II) redox couple in an equimolar mixture of molten NaCl-KCl
Kuznetsov,Gaune-Escard
, p. 1101 - 1111 (2001)
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.
Photoluminescence of Ba(SCN)2:Eu2+
Wickleder, Claudia
, p. 10 - 13 (2004)
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+.
An efficient bonding-type Eu-containing copolymer as red phosphor applied in LED
Yan, Haigang,Wang, Huihui,He, Pei,Shi, Jianxin,Gong, Menglian
, p. 1065 - 1068 (2011)
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
Synthesis and photoluminescence properties of novel europium complexes of 2′-hydroxyacetophenone and 4,6-diacetylresorcinol
Liu, Sheng-Li,Wen, Chun-Lin,Qi, Su-Su,Liang, En-Xiang
, p. 664 - 669 (2008)
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.
Synthesis and luminescent properties of gadolinium aluminates phosphors
Matos, Marcela G.,Calefi, Paulo S.,Ciuffi, Katia J.,Nassar, Eduardo J.
, p. 63 - 69 (2011)
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.
Structural and spectroscopic investigations of europium(III) entrapped by the ethylenediaminetetra(methylenephosphonate) ligand in K12H8[Eu4(EDTMP)4] · 45H2O crystal
Janicki, Rafa?,Mondry, Anna
, p. 1942 - 1946 (2008)
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
In situ synthesis and luminescence characteristics of complexes of europium(III) with 4,6-diacetylresorcinol
Liu, Sheng-Li,Wen, Chun-Lin,Chen, Chun,Qi, Su-Su,Liang, En-Xiang
, p. 2397 - 2402 (2008)
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.
Study of the annealing temperature effect on the structural and luminescent properties of SrWO4:Eu phosphors prepared by a non-hydrolytic sol-gel process
Pereira,De Moura,Nogueira,Lima,Longo,De Sousa Filho,Serra,Nassar,Rosa
, p. 11 - 21 (2012)
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.
Synthesis, thermal properties and spectroscopic study of solid mandelate of light trivalent lanthanides
Gigante,Gomes,Lima,Caires,Treu-Filho,Ionashiro
, p. 6 - 14 (2012/05/31)
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.
