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Thiacalix[4]arene-Supported Tetranuclear Tb <sup>III</sup> and Eu <sup>III</sup> Compounds: Synthesis, Structure, Luminescence, and Magnetism
摘要： Two tetranuclear compounds [Ln4Na(μ4-OH)(TC4A)2(acac)4] [Ln = Tb (1), Eu (2)] (acac = acetylacetonate) were synthesized and characterized based on p-tert-butylthiacalix[4]arene (H4TC4A). Compounds 1 and 2 are isostructural and crystallize in the monoclinic C2/c space group. There are two crystallographically independent metal atoms in one asymmetric unit. Ln1, Ln2, and two metal atoms generated by the symmetry operation are bridged by one μ4-OH group to form a planar tetragonal Ln4(μ4-OH) unit. Each Ln4(μ4-OH) unit is surrounded by four acac anions and two disordered sodium ions in the planar direction. The upper and lower positions of the Ln4(μ4-OH) unit are further coordinated by two cone-shaped TC4A ligands to form a sandwich-type molecular structure. Luminescent measurements reveal that both compounds 1 and 2 exhibit good photoluminescent properties. Moreover, the static and dynamic magnetic properties of compound 1 were also investigated, which demonstrates that 1 is one functional material candidate combining luminescent and antiferromagnetic properties in one molecule.
关键词： Thiacalix[4]arene,Lanthanides,Cluster compounds,Magnetic properties / Luminescence,Coordination chemistry
更新于2025-09-19 17:15:36
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Lanthanide-doped MgO: A case study on how to design new phosphors for dosimetry with tailored luminescent properties
摘要： In this work we systematically investigated undoped and lanthanide(Ln)-doped MgO with diverse dopant combinations, MgO:Ce,Ln and MgO:Tb,Ln, where Ln=Eu, Yb, Tm, Sm, Dy, Nd, as well as the same combinations with an additional 3 mol% Li dopant. We characterized the thermoluminescence (TL), optically stimulated luminescence (OSL), radioluminescence (RL), TL emission spectra and OSL emission spectra. Our investigation indicates that Ce3+ and Tb3+ act as recombination centers and their characteristic spectra are observed under thermal or optical stimulation. Conversely, TL measurements suggests that Sm3+, Tm3+ and Yb3+ probably act as electrons traps. The role of Li was investigated, since it was found to increase the RL, TL and OSL intensities in MgO. As part of the present investigation, we identified promising OSL materials sensitive to ionizing irradiation with distinct luminescent properties.
关键词： Optically stimulated luminescence,Dosimetry,Thermoluminescence,Lanthanides
更新于2025-09-19 17:15:36
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Illuminating the intermolecular vs intramolecular excited state energy transfer quenching by Europium(III) ions
摘要： Bright lanthanide based probes relies on sensitised lanthanide luminescence. The outcome of the excited state energy transfer cascade—from sensitizer chromophore to lanthanide(III) ion—should be population of the lanthanide excited state with unity efficiency. This is rarely the case, and is a particular problem for europium(III) due to the low energy of the Eu(II)/Eu(III) redox couple. Thus, photoinduced electron transfer quenching can be an efficient drain for the excited state energy, reducing the brightness of a probe. Here, the effect of intramolecular PeT in a lanthanide based probe is investigated by contrasting intramolecular processes in coumarin-appended 1,4,7,10-tetraazacyclododecane-1,4,7-triacetate (DO3A) complexes to intermolecular processes induced through collisional quenching. We find that the excited energy transfer processes involving terbium(III) and europium(III) are slow in the complex when compared to collisional quenching. Further, we show that the quenching event may lead to lanthanide luminescence and suggest that the fate of a PeT quenching event may not be non-radiative loss of the excitation energy.
关键词： Lanthanides,Fluorescence,Luminescence,Excited State Energy Transfer,Solution Structure
更新于2025-09-19 17:15:36
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Photo-physical studies of ultrasmall upconversion nanoparticles embedded organometallic complexes: Probing a dual mode optical sensor for hydrogen peroxide
摘要： Here, we report an upconversion nanoparticles (UCNPs) embedded organomettalic complex for detection of hydrogen peroxide (H2O2). The structural as well as the optical properties of the hybrid nanoparticles (HNPs) have been studies to confirm the interaction as well as energy transfer mechanism. The structural characterization confirm the weak interacting force between the UCNPs and the organic complex in HNPs. The optical studies reveal that, HNPs show characteristic optical behaviour of both the phases i.e. it gives an intense downconverted red emission under UV excitation, due to the presence of organic part (Eu3t ion) as well as an efficient blue upconverted emission from inorganic part (Tm3t ion) under NIR excitation. The energy transfer between the inorganic (Tm3t ion) and the organic (Eu3t ion) material has been observed, which confirms the effective attachment of both the phases in HNPs. The upconversion and downconversion emission properties, have been have successfully utilized for dual mode H2O2 detection.
关键词： Hydrogen peroxide sensor,Lanthanides,Hybrid nanoparticles,Energy transfer
更新于2025-09-19 17:13:59
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Detection of E. coli labeled with metal-conjugated antibodies using lateral-flow assay and laser-induced breakdown spectroscopy
摘要： This study explores the adoption of laser-induced breakdown spectroscopy (LIBS) for the analysis of lateral-flow immunoassays (LFIAs). Gold (Au) nanoparticles are standard biomolecular labels among LFIAs, typically detected via colorimetric means. A wide diversity of lanthanide-complexed polymers (LCPs) are also used as immunoassay labels but are inapt for LFIAs due to lab-bound detection instrumentation. This is the first study to show the capability of LIBS to transition LCPs into the realm of LFIAs, and one of the few to apply LIBS to biomolecular label detection in complete immunoassays. Initially, an in-house LIBS system was optimized to detect an Au standard through a process of line selection across acquisition delay times, followed by determining limit of detection (LOD). The optimized LIBS system was applied to Au-labeled Escherichia coli detection on a commercial LFIA; comparison with colorimetric detection yielded similar LODs (1.03E4 and 8.890E3 CFU/mL respectively). Optimization was repeated with lanthanide standards to determine if they were viable alternatives to Au labels. It was found that europium (Eu) and ytterbium (Yb) may be more favorable biomolecular labels than Au. To test whether Eu-complexed polymers conjugated to antibodies could be used as labels in LFIAs, the conjugates were successfully applied to E. coli detection in a modified commercial LFIA. The results suggest interesting opportunities for creating highly multiplexed LFIAs. Multiplexed, sensitive, portable, and rapid LIBS detection of biomolecules concentrated and labeled on LFIAs is highly relevant for applications like food safety, where in-field food contaminant detection is critical.
关键词： Lateral-flow immunoassay,E. coli,Laser-induced breakdown spectroscopy,Lanthanides,Metal-conjugated antibodies
更新于2025-09-16 10:30:52
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Solar spectral conversion based on plastic films of lanthanide-doped ionosilicas for photovoltaics: down-shifting layers and luminescent solar concentrators
摘要： The mismatch between the photovoltaic (PV) cells absorption and the solar irradiance on earth is one of the major limitations towards more efficient PV energy conversion. This aspect was addressed by down-shifting the solar irradiance on Earth through luminescent down-shifting layers based on lanthanide-doped surface-functionalized ionosilicas (ISs) embedded in poly(methyl methacrylate) (PMMA) coated on the surface of commercial Si-based PV cells. The IS-PMMA hybrid materials exhibit efficient solar radiation harvesting (spectral overlap of ~ 9.5· 1019 photons/(s· m)) and conversion (quantum yield ~ 52%). The direct solar radiation and the down-shifted radiation are partially guided and lost through total internal reflection to the layer edges being unavailable for PV conversion of the coated PV cell. By tuning the down-shifting layer thickness, it also acts as luminescent solar concentrator enabling the collection of the guided radiation by flexible PV cells applied on the borders of the down-shifting layer leading to an enhancement of the PV energy conversion from ~ 5% (in the case of the single-use of the luminescent down-shifting layer) to ~ 13% comparing to the bare PV cell. The overall electrical output of the device resulted in an absolute external quantum efficiency increase of ~32% for the optimized Eu3+-based films in the UV spectral region (compared with the bare PV device, which is among the best values reported so far).
关键词： silicon photovoltaic cells,photovoltaics,ionosilicas,lanthanides,luminescent solar concentrators,down-shifting layers
更新于2025-09-16 10:30:52
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MELISSA: Laser ion source setup at CERN-MEDICIS facility. Blueprint
摘要： The Resonance Ionization Laser Ion Source (RILIS) has become an essential feature of many radioactive ion beam facilities worldwide since it offers an unmatched combination of efficiency and selectivity in the production of ion beams of many different chemical elements. In 2019, the laser ion source setup MELISSA is going to be established at the CERN-MEDICIS facility, based on the experience of the workgroup LARISSA of the University Mainz and CERN ISOLDE RILIS team. The purpose is to enhance the capability of the radioactive ion beam supply for end users by optimizing the yield and the purity of the final product. In this article, the blueprint of the laser ion source, as well as the key aspects of its development and operation are presented.
关键词： Laser resonance ionization,Lanthanides,Ti:sapphire,MELISSA,Isotope separation,Nuclear medicine,CERN-MEDICIS
更新于2025-09-16 10:30:52
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Self‐Assembled Tetrameric Lanthanide‐Containing Germanotungstates [(Ln <sub/>2</sub> GeW <sub/>10</sub> O <sub/>38</sub> ) <sub/>4</sub> (W <sub/>3</sub> O <sub/>8</sub> )(OH) <sub/>4</sub> (H <sub/>2</sub> O) <sub/>2</sub> ] <sup>26?</sup> : Syntheses, Crystal Structure, Photoluminescence and Electrochemical Properties.
摘要： A series of six lanthanide-containing germanotungstates of the formula: [(Ln2GeW10O38)4(W3O8)(OH)4(H2O)2]26? (Ln=Sm (1), Eu (2), Gd (3), Tb (4), Dy (5), Ho (6) have been synthesized under ambient conditions. The synthetic procedure involves the use of trilacunary Na10[A-α-GeW9O34]?16H2O as a preformed precursor along with lanthanide salts in 0.5 M potassium chloride solution. The interaction of the trilacunary Na10[A-α-GeW9O34]?16H2O with the lanthanide salts leads to the formation of a tetrameric structure with four [GeW10O36]8? dilacunary Keggin units incorporating eight lanthanide ions and three additional tungsten atoms. All the polyanions were structurally characterized by Fourier-transform infrared spectroscopy (FT-IR), Single Crystal X-ray Diffraction (SC-XRD), UV/Visible spectroscopy, thermogravimetric analysis (TGA), electrochemistry, Electron-spray ionization mass spectroscopy (ESI-MS), Powder X-ray diffraction (PXRD) and photoluminescence. FT-IR spectroscopy reveals that all the polyanions are isomorphous and SC-XRD shows that all the polyanions are isostructural and crystalize in the triclinic crystal system with P1 space group. Some of the polyanions show good photoluminescence properties. The cyclic voltammograms (CVs) of all the six compounds exhibit the same shape, each being composed of a pronounced reduction wave.
关键词： Polyoxometalates,Lanthanides,Electrochemistry,Photoluminescence,Germanotungstate
更新于2025-09-11 14:15:04
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Solid-state synthesis of LnOCl/Ln2O3 (Ln?= Eu, Nd) by using chitosan and PS-co-P4VP as polymeric supports
摘要： A series of lanthanide materials of type LnOCl or Ln2O3 (Ln ? Eu, Nd) were successfully prepared via a convenient and straightforward two-step procedure. Firstly, and by using chitosan and PS-co-P4VP as polymeric supports, macromolecular complexes of type chitosan$LnCl3 and PS-co-P4VP$LnCl3 were prepared. These macromolecular complexes were treated in solid state at 800 (cid:2)C under air, leading to the corresponding LnOCl or Ln2O3 materials (Ln ? Eu, Nd) with moderate to good yields. The nature of the as-prepared lanthanide materials (LnOCl and/or Ln2O3) is strongly in?uenced by the polymeric template (i.e., chitosan or PS-co-P4VP), the lanthanide salt precursor, and the polymer/lanthanide molar ratio. Thus, when chitosan$EuCl3 and PS-co-P4VP$EuCl3 are used as macromolecular precursors, a mixture of crystalline phases of both EuOCl and Eu2O3 are obtained. However, when chitosan$NdCl3 and PS-co-P4VP$NdCl3 are used, a sole pure crystalline phase of NdOCl is obtained. The nanostructured lanthanide materials were characterized by means of XRD (X-ray diffraction of powder), SEM, EDS, TEM, and HRTEM. The luminescent spectra of the as-prepared EuOCl/Eu2O3 mixture materials show an emission pattern whose intensity is strongly in?uenced by the nature of the polymeric precursor, as well as on the metal/polymer molar ratios.
关键词： NdOCl,EuOCl/Eu2O3,Lanthanides,Luminescence,Rare earths,Solventless method
更新于2025-09-10 09:29:36
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Homodinuclear {LnIII2} (LnIII = GdIII, TbIII, HoIII, and DyIII) Complexes: Field- Induced SMM Behavior of the DyIII and TbIII Analogues
摘要： A family of four dinuclear complexes, [NHEt3]2[Ln2(μ-NO3)2(NO3)2(HL)2] [Ln = GdIII (1), TbIII (2), HoIII (3), DyIII (4)], were synthesized by the reaction of an enolizable mutidentate Schiff base ligand H3L (H3L = N'-(2-hydroxy-3-methoxy-5-nitrobenzylidene)-2-(hydroxyimino)propanehydrazide) with hydrated lanthanide nitrates in the presence of NEt3. The molecular structure of complexes 1-4 was confirmed by single-crystal XRD analysis. All of the centrosymmetric complexes are dianionic, isostructural and each of the LnIII center is nine-coordinated and adopts a muffin like coordination geometry as indicated by SHAPE analysis. The dynamic magnetization studies revealed that the compounds 2 and 4 are field-induced single-molecule magnets with effective energy barriers, Ueff = 34(2) K (for 2) and 80(3) K (for 4) and pre-exponential factors, τo = 1.1 x 10-8 (for 2) and 1.15 x 10-7(for 4).
关键词： Tautomerism,Lanthanides,Schiff bases,Homodinuclear complexes,Magnetism
更新于2025-09-10 09:29:36