Eu Metal Research Articles

Effect of Europium Complexation on N,N,N′,N′-Tetraoctyldiglycolamide Degradation Against Gamma Radiation

AbstractDiglycolamide extractants (DGAs) are playing an important role for many of aqueous separation processes under development for the advanced nuclear fuel cycle. This family of ligands exhibits excellent extracting and resistant properties, with TODGA (N,N,N′,N′-tetraoctyldiglycolamide) being a particularly successful extractant studied intensively in recent decades. Nowadays, the main issues for TODGA-based solvents are related to the understanding and simulation of the radiolytic degradation under realistic conditions, which is limiting aspect for the development of an advanced aqueous nuclear separation process. In that sense, in this work, TODGA ligand stability, solvent composition and performance were evaluated considering the effect of metal complexation under gamma radiation. For that, the irradiation of a TODGA solvent in the presence of Eu metal was carried out, varying the ligand/metal ratio. The goal was to not only study TODGA degradation using HPLC–MS technique but also to identify and quantify its degradation compound under these experimental conditions. The results revealed a protection of TODGA molecules due to metal ion complexation, with no observed changes in the degradation pathway, as confirmed by the quantification of formed degradation compounds.

Electronic Devices Made from Chitin: NAND Gates Made from Chitin Sorbates and Unsaturated Bridging Ligands—Possible Integration Levels and Kinetics of Operation

Chitin (usually derived from aq. arthropods like shrimp Pandalus borealis) acts as a potent metal sorbent in both environmental monitoring and retention applications such as wastewater purification or nuclear fuel reprocessing. Given this established (starting in the 1970s) use of chitin and the fact that adsorption of metal ions/complexes to chitin does increase the currents observed in metal-centered redox couples by a factor of about 10, it is straightforward to conceive self-organized (by adsorption modified by adding certain ligands bridging M and chitin) surface films which exert electrical information processing by means of inner-sphere redox processes. Preliminary work is shown concerning the influence of ligands—including some possibly acting as inner-sphere-transfer agents, like caffeic acid—on metal ion retention by chitin. Another ligand is reported to enhance current flow into electrodes (i.e., electron injection from some reducing cation). These inner-sphere redox processes, in turn, can be controlled by creating or removing a chain of conjugated double bonds, e.g., by Diels–Alder reactions. Devices admitting corresponding reagents in a controlled manner and appropriate array then act as NAND gates, thus being components capable of performing each kind of classical computation. Applications in environmental analysis and “green” computing for simple purposes like electronic keys are suggested. The empirical basis for these conclusions includes studies on the influences of ligand additions on M adsorption (Mn, Ni, several REEs…) on chitin; some of these bridging ligands, like caffeinate and ferulate, can reversibly react with appropriate dienes. At the employed concentrations, distances among adsorbed metal ions are 1–3 nm, meaning that the charge-flow control takes spacer ligands like carotenoids. Practical setups are pointed to, using evidence from ligand-augmented metal ion–chitin interactions, which might combine oxidizing (Ce) and optically address reducing (Eu) metal ions into a framework for coligand-controlled charge flow.

Electrochemical and Spectroscopic Properties of Europium in AlCl3-NaCl Melts

The physicochemical properties of Eu cations in AlCl3-NaCl melts have been studied for the purpose of spent nuclear fuel recycling via electrochemical and spectroscopic methods. Eu metal dissolves in the AlCl3-NaCl melts to generate divalent europium and Al metal while releasing chlorine gas. The effect of Lewis acidity of melt on the electrochemical behaviors of Eu(II) has been studied. In Lewis base melt of AlCl3-NaCl, Eu(III), and Al(III) can be co-reduced at the potential between Al deposition and Eu(II) oxidation. With the enhanced Lewis acidity of the molten salt, Eu(II) diffusion becomes more facile. The in situ absorption spectra of Eu(II) in AlCl3-NaCl melts reveal that the complexation ligand of Eu(II) changes with the melt Lewis acidity, thereby affecting the electrochemical behaviors of Eu(II) species. In addition, the redox potential of the Eu(II)/Eu(III) conversion reaction is more positive than that of Sm(II)/Sm(III).

3D water stable Eu(III)-organic framework as recyclable multi-responsive luminescent sensor for efficient detection of lead ion, permanganate anion and para-nitrophenol in aqueous medium

Using a mixed ligand strategy a novel 3D Eu(III) metal–organic framework with tetranuclear SBUs formulated as [Eu2(NTA)2(Ada)(DMF)2] (Cj-1) was solvothermally synthesized by employing 2-nitroterepthalic acid (NTA) as antenna and adipic acid (Ada) as bridging spacer. Multiple coordination modes and bright fluorescence characteristics make Cj-1 ideal as fluorescent probe. Fluorescence studies reveal that Cj-1 emits intense red luminescence and displays excellent water stability and outstanding chemical stability over broad pH range (pH = 2–10). The Cj-1 exhibits strong luminous sensing response against inorganic ions Pb2+, MnO4−, and para-nitrophenol in water with high sensitivity, selectivity, rapid reaction and an outstanding recycle usage. It is interesting to note that the solid sample's color changes from white to brown upon detection of the MnO4− ions. This color change signifies luminescence induction, making the method for detecting MnO4− ions simple and more practical to everyday life. Powder X-ray diffraction, infrared spectroscopy, elemental analysis, and luminescence methods were used to characterize the compound. The potential sensing mechanisms of Cj-1for selective sensing have been thoroughly investigated.

Yttrium aluminum garnet based novel and advanced phosphor synthesized by combustion route activated by Dy, Eu, and Tb rare earth metals

Yttrium aluminum garnet based novel and advanced phosphor synthesized by combustion route activated by Dy, Eu, and Tb rare earth metals

Synthesis and characterization of europium (III), terbium (III) complexes and their mixture for making white light emission powder

The enhanced luminescence of lanthanide complexes coordinated to antenna ligands has potential applications for developing devices like screens and lamps. Herein, three β-diketone antenna ligands were incorporated into Eu(III) and Tb(III) metals to synthesize five complexes. Their luminescence properties in solid state and the energy levels of the electronic states for the ligands and the metals were recorded and probed by UV–vis and fluorescence spectroscopies. Under UV light, a white-light emission powder was observed by mixing red-emission europium and green-emission terbium complexes, with blue-emission laundry powder. The powder composition was tuned by using spectroscopic analysis and CIE 1931 color diagram.

Expedient synthesis and luminescence sensing of the inositol pyrophosphate cellular messenger 5-PP-InsP5.

Inositol pyrophosphates are important biomolecules associated with apoptosis, cell growth and kinase regulation, yet their exact biological roles are still emerging and probes do not exist for their selective detection. We report the first molecular probe for the selective and sensitive detection of the most abundant cellular inositol pyrophosphate 5-PP-InsP5, as well as an efficient new synthesis. The probe is based on a macrocyclic Eu(iii) complex bearing two quinoline arms providing a free coordination site at the Eu(iii) metal centre. Bidentate binding of the pyrophosphate group of 5-PP-InsP5 to the Eu(iii) ion is proposed, supported by DFT calculations, giving rise to a selective enhancement in Eu(iii) emission intensity and lifetime. We demonstrate the use of time-resolved luminescence as a bioassay tool for monitoring enzymatic processes in which 5-PP-InsP5 is consumed. Our probe offers a potential screening methodology to identify drug-like compounds that modulate the activity of enzymes of inositol pyrophosphate metabolism.

Reinvestigation of Reactions of HgPh2 with Eu and Yb Metal and the Synthesis of a Europium(II) Bis(tetraphenylborate).

Europium bis(tetraphenylborate) [Eu(thf)7][BPh4]2⋅thf containing a fully solvated [Eu(thf)7]2+ cation, was synthesized by protolysis of "EuPh2" (from Eu and HgPh2) with Et3NHBPh4, and the structure was determined by single-crystal X-ray diffraction. Efforts to characterize the putative "Ph2Ln" (Ln = Eu, Yb) reagents led to the synthesis of a mixed-valence complex, [(thf)3YbII(μ-Ph)3YbIII(Ph)2(thf)]⋅2thf, resulting from the reaction of Yb metal with HgPh2 at a low temperature. This mixed-valence YbII/YbIII compound was studied by 171Yb-NMR spectroscopy and single-crystal X-ray diffraction, and the oxidation states of the Yb atoms were assigned.

Structure and Reactivity of Polynuclear Divalent Lanthanide Disiloxanediolate Complexes.

Trinuclear molecular complexes of europium (II) and ytterbium(II) [Ln3{(Ph2SiO)2O}3(THF)6], 1-Ln3L3 (Ln = Eu and Yb), supported by the dianionic tetraphenyl disiloxanediolate ligand, were synthesized via protonolysis of the [Ln{N(SiMe3)2}2(THF)2] complexes. In contrast, the reaction of [Sm{N(SiMe3)2}2(THF)2] with the (Ph2SiOH)2O ligand led to the isolation of the mixed-valent Sm(II)/Sm(III) complex [Sm3{(Ph2SiO)2O}3{N(SiMe3)2}(THF)4], 2-Sm3L3, which was crystallographically characterized. The Eu(II) complex 1-Eu3L3 displays weak ferromagnetic coupling between the Eu(II) metal centers (J = 0.1035 cm-1). The addition of 3 equiv of (Ph2SiOK)2O to 1-Eu3L3 resulted in the formation of the polynuclear Eu(II) dimer of dimers [K4Eu2{(Ph2SiO)2O}4(Et2O)2]2, 3-Eu2L4. Complexes 1-Ln3L3 (Ln = Eu and Yb) are stable in solution at room temperature, while 3-Eu2L4 shows higher reactivity and rapidly decomposes to give the mixed-valent Eu(II)/Eu(III) species [K3Eu2{(Ph2SiO)2O}4], 4-Eu2L4. Complex 1-Yb3L3 affects the slow reductive disproportionation of carbon dioxide, but 1-Eu3L3 does not display any reactivity toward CO2. However, the presence of one additional (Ph2SiO-)2O per Eu(II) metal center in 3-Eu2L4 increases dramatically the reductive ability of the Eu(II) metal centers, affording the first example of carbon dioxide activation by an isolated divalent europium complex. The reduction of CO2 by 3-Eu2L4 is immediate, and carbonate is formed selectively after the addition of a stoichiometric amount of CO2.

Novel Dual-Signal Electrochemiluminescence Aptasensor Involving the Resonance Energy Transform System for Kanamycin Detection.

Based on luminol-capped Pt-tipped Au bimetallic nanorods (NRs) (L-Au-Pt NRs) as the anode emitter and SnS2 quantum dots (QDs) hybrid Eu metal organic frameworks (MOFs) (SnS2 QDs@Eu MOFs) as the cathode emitter, a dual-signal electrochemiluminescence (ECL) platform was designed for the ultrasensitive and highly selective detection of kanamycin (KAN). Using a dual-signal output mode, the ratiometric ECL aptasensor largely eliminates false-positives or false-negatives by self-calibration in the KAN assay process. To stimulate the resonance energy transform (RET) system, the KAN aptamer and complementary DNA are introduced for conjugation between the donor and acceptor. With the specific recognition of target KAN by its aptamer, L-Au-Pt NRs-apt partially peels off from the electrode surface. Eventually, the RET system is removed, leading to an increasing cathode signal and a decreasing anode signal. In view of this phenomenon, the ratiometric aptasensor can quantify KAN from 1 pM to 10 nM with a low detection limit of 0.32 pM. This dual-signal ECL aptasensor exhibits great practical potential in environmental monitoring and food safety.

Highly improved photoluminescence properties of novel ternary Eu(cpioa)phen metal–organic frameworks

In this work, a novel ternary Eu (III) metal–organic frame-Eu(cpioa)phen (H3cpioa: 5-(4-carboxy-lphenoxy)-isophthalic, phen: 1,10-phenanthroline monohydrate) was synthesized by a facile hydrothermal method. Structural and optical properties of the binary and ternary Eu (III) MOF were studied in detail. Results show that, compared with the binary Eu(cpioa) MOF, the photoluminescence intensity of the ternary Eu(cpioa)phen MOF is increased by 13.04 times, and the quantum efficiency is increased by 67.2%. The major possible reason for the highly improved photoluminescence properties might be due to the antenna effect induced by the addition of phen. Also, the highly improved crystallinity may also contribute to the greatly increased photoluminescence intensity and quantum efficiency.

Synthesis and characterisation of η6-arene(halogenidoaluminato)-lanthanoid(II) and alkaline earth(II) complexes

η6-Arene(iodidoaluminato)lanthanoid(II) complexes, {[Ln(η6-C6H5Me)(AlI4)2]}n [Ln = Sm, 1, Eu, 2, Yb, 3; C6H5Me = toluene] have been prepared by reactions of in situ generated aluminium triiodide with the corresponding lanthanoid metals and 1,2-diiodoethane in toluene (molar ratio: 2:1:1). Compounds 1–3 are polymeric and the lanthanoid(II) atom of 1 and 2 is coordinated by an η6–arene and three chelating κ (I, I′) tetraiodidoaluminate ligands, two of which are also bridging (LnI2AlI2Ln) and one is terminal. 3 is coordinated by an η6–arene, one terminal chelating κ (I, I′) and one chelating and bridging (YbI2AlI2Yb) tetraiodidoaluminate ligand, and one monodentate tetraiodidoaluminate ligand, which is also bridging (YbIAl(I)I2Yb). These are the first X-ray crystal structures of arene(tetrakisiodidoaluminato)lanthanoid(II) complexes. The first reported alkaline earth(II) (η6–arene)iodidoaluminate complexes, namely [Ca(η6-C6H5Me)(AlI4)2]n (4), {[Sr(η6-C6H5Me)(AlI4)2]n·nPhMe} (5), [Ba(η6-C6H5Me)2(AlI4)2] (6), [Ca(η6-C6H3Me3-1,3,5)(AlI4)2]n (7) and {[Sr(η6-C6H3Me3-1,3,5)(AlI4)2]n·0.5n(PhMe3)} (8) have also been obtained in an arene (toluene or mesitylene) solution by a similar method. Complex 4 is isocoordinate with 3, and 5 is isomorphous with 2. Complex 7 has eight coordinate Ca similar to 4, and complex 8 has nine coordinate Sr as in 5. Mononuclear ten coordinate complex 6 is the first example of a monomeric η6–arene sandwich complex of barium. The EuII bromidoaluminate complex {[Eu(η6-C6H5Me)(AlBr4)2]n·0.5nPhMe} (9) has been prepared from Eu metal, AlBr3, and BrCH2CH2Br in toluene and has a unit cell similar to 8 despite the different metal and arene.

Synthesis of photoluminescent europium dithiocarbamate complexes with dimethyl phenanthroline and bipyridyl co-ligands

This paper reports the synthesis of photoluminescent europium diphenylamine and piperidine dithiocarbamate complexes compound containing co-ligands 2,9 dimethyl-1,10 phenanthroline and bipyridyl. Nuclear magnetic resonance analysis result indicated that the complex compound of europium diphenylamine dithiocarbamate-2,9 dimethyl-1,10 phenanthroline [(dpa-dtc)2--Eu-(Dmphen)] has an Eu metal to bind to 2 diphenylamine dithiocarbamate ligands in bidentate structure. Meanwhile, the piperidine dithiocarbamate-2,2 bipyridyl [(pip-dtc)-Eu-(Bipy)] indicates the structure to have 1 Bipy co-ligand and 1 piperidine dithiocarbamate ligand which is monodentate bonded to the Eu metal. The photoluminescence analysis results showed that the [(dpa-dtc)2-Eu-(Dmphen)] and [(pip-dtc)-Eu-(Bipy)] complexes exhibited a photoluminescent in the region of red-orange, which is associated with the electronic transition of 5D0 → 7F2. Europium dithiocarbamate complex compounds have the potential to be applied as an active material for display and others electronics devices applications.

Yttrium Aluminium Garnet Based Novel and Advanced Phosphor Synthesized by Combustion Route Activated by Dy, EU, and Tb Rare Earth Metals

Yttrium Aluminium Garnet Based Novel and Advanced Phosphor Synthesized by Combustion Route Activated by Dy, EU, and Tb Rare Earth Metals

A Eu(iii) metal-organic framework based on anthracenyl and alkynyl conjugation as a fluorescence probe for the selective monitoring of Fe3+ and TNP.

In this work, a luminescent metal-organic framework (Eu-MOF {[Eu6L6(μ3-OH)8(H2O)3]8·H2O} n ) was constructed by a solvothermal method with a linear organic ligand L (10-[(2-amino-4-carboxyl-phenyl)ethynyl]anthracene-9-carboxylic acid) based on anthracene and alkyne groups and using Eu3+ as the metal center. The MOF exhibits a stable UiO-66 crystal structure, and a six-core cluster twelve-linked secondary structural unit was successfully synthesized using 2-fluorobenzoic acid as a modulator, forming a classical fcu topology. Moreover, it exhibits good chemical stability. Interestingly, Eu-MOF exhibited high selectivity and sensitive fluorescence burst properties towards Fe3+ ions and 2,4,6-trinitrophenol (TNP) in DMF solution. For Fe3+, the K SV value is 5.06 × 105 M-1 and the LOD value is 5.1 × 10-7 M. For TNP, the K SV value is 1.92 × 104 M-1 and the LOD value is 1.93 × 10-6 M. In addition, Eu-MOF showed good anti-interference ability and fast response. This work provides an excellent fluorescent sensor for the detection of Fe3+ and 2,4,6-trinitrophenol (TNP) residues in contaminants.

A multi-responsive luminescent sensor based on a stable Eu(iii) metal–organic framework for sensing Fe3+, MnO4−, and Cr2O72−in aqueous solutions

A stable benzothiadiazole-based Eu(iii) metal–organic framework withccotopology has been successfully constructed, and represents the multifunctional fluorescence sensor toward Fe3+, MnO4−and Cr2O72−in aqueous solutions.

Сверхизлучение и синтез наночастиц металла в полистирольном композите с многоспиновыми комплексами Eu при быстром одноосном сдавливании

Composites of heterospin molecular magnet [EuIII(SQ)3bipy] in a polystyrene (PS) matrix have been synthesized. This complex [EuIII(SQ)3bipy] contains four paramagnetic centers - the Eu3+ ion and three SQ ligands (SQ—3,6-di-tert-butyl benzoquinone radical anion); bipy (bipyridyl) is diamagnetic. It has been established that intensive mechanical activation of [EuIII(SQ)3bipy]/PS samples leads to an reological explosion, as a result of which radio frequency superradiance, the appearance of free electrons and the formation of Eu metal nanoparticles are observed. The duration of this process is 10 ns.

Y2O3:Eu and the Mössbauer isomer shift coefficient of Eu compounds from ab-initio simulations

We report on a full potential density functional theory characterization of Y2O3 upon Eu doping on the two inequivalent crystallographic sites 24d and 8b. We analyze local structural relaxation, electronic properties and the relative stability of the two sites. The simulations are used to extract the contact charge density at the Eu nucleus. Then we construct the experimental isomer shift (IS) versus contact charge density calibration curve, by considering an ample set of Eu compounds: EuF3, EuO, EuF2, EuS, EuSe, EuTe, EuPd3 and the Eu metal. The, expected, linear dependence has a slope of α = 0.054 mm s−1 Å− 3, which corresponds to nuclear expansion parameter ΔR/R = 6.0 × 10−5. α allows to obtain an unbiased and accurate estimation of the IS for any Eu compound. We test this approach on two mixed-valence compounds Eu3S4 and Eu2SiN3, and use it to predict the Y2O3:Eu IS with the result +1.04 mm s−1 at the 24d site and +1.00 mm s−1 at the 8b site.

Boric-acid-functionalized luminescent sensor for detection of chromate ions in aqueous solution

The development of highly fluorescent materials for detection of environmental contaminants like chromate anions (Cr2O72−) is of great importance. Here, boric acid-coated Eu(III) metal–organic framework (Eu-MOF-B) was successfully synthesized using one pot hydrothermal conditions and further extensively characterized by several spectroscopic and microscopic techniques. The fluorescence spectroscopy investigations indicated the dual-fluorescence emission along with high stability in water. In case of presence of Cr2O72− ion in aqueous samples, the red fluorescence of Eu-MOF-B is selectively quenched but blue fluorescence is enhanced. Hence, the complex could be a potential fluorescent sensor for sensitive detection of Cr2O72− with a low limit of detection of 0.17 ppm.

Epitaxial Growth of EuF2 and EuO Thin Films Based on Spontaneous Anion Diffusion from Substrates

We report the epitaxial growth of EuF2 (111) thin films on F-ion-conducting CaF2 (111) substrates. We achieved the fluorination of the Eu metal without introducing fluorination gas into the vacuum chamber during magnetron sputtering; instead, F atoms were supplied by the substrates. This growth method also allows EuO (100) epitaxial thin films to be fabricated on O-ion-conducting yttria-stabilized zirconia substrates. X-ray diffraction, transmission electron microscopy, and optical absorption spectra verified that the proposed method yields high-quality EuF2 and EuO thin films. Therefore, this study presents a novel thin-film growth method based on spontaneous anion diffusion from substrates.