Europium Chloride Research Articles

Luminescent study of Eu(OOCC6H5)3·3(H2O) complex dispersed on polyvinyl alcohol films: Crystal structure, interaction and quenching effect

This study presents the preparation of a mononuclear complex of europium and benzoic acid and its interaction with polyvinyl alcohol films. The europium complex was prepared from europium (III) chloride hexahydrate (EuCl3 · 6H2O), and sodium benzoate (C7H5NaO2), and it was established that the ligand is attached to the metal ion through the carbonyl group anchored by bidentate interaction, obtaining a mononuclear complex powder with the formula Eu(OOCC6H5)3·3(H2O) (identified as EuBA3). First, the crystal structure solution for the complex powder was carried out, showing a monoclinic P2 space group with two molecules in the unit cell, the resulting crystal structure was deposited in the CCDC service with number 2370755. Afterward, the complex was deposited on polyvinyl alcohol films, to study the interactions between them, the morphological and luminescent properties were also evaluated. This work details the synthesis, of a complex made of europium and sodium benzoate and its luminescent properties as a complex deposited at different concentrations on polyvinyl alcohol films, the results obtained showed a shift in the excitation wavelength from the EuBA3 powder complex when incorporated into the PVA films. The concentration of the complex in the film increases until reaching a maximum followed by a decrease due to quenching.

A dual-functional rare earth halide additive for high-performance aqueous zinc ion batteries

Aqueous zinc ion batteries have received much attention due to their high theoretical capacity, inherent safety, and low cost. However, the growth of zinc dendrites and side reactions hinder its practical application. In this study, a rare-earth metal salt, europium chloride (EuCl3), is used as a new electrolyte additive to regulate the uniform deposition of zinc and inhibit the interfacial side reactions. The EuCl3 additive benefits for preferentially Zn2+ deposition along the (002) crystal plane, as well as suppress the hydrogen evolution reaction (HER) at electrode-electrolyte interface. As a result, the capacity retention of the Zn//NaV3O8 full cell assembled with the modified electrolyte much better than that without additives, showing a long-term cycling life and high coulombic efficiency at a current density of 10 A g−1. This new dual-functional rare earth halide additive strategy provides great potential for the development of practical aqueous zinc ion batteries and other battery systems.

Polarization Processes in Nafion Composite Membranes Doped with Rare-Earth Metals.

Dielectric spectroscopy (frequency range f = 100…107 Hz and temperatures T = 293…403 K (accuracy 0.5 K), measuring voltage applied to the sample was 1.0 V) was used to study composite materials based on perfluorosulfonic membranes with inclusions of rare-earth elements, in particular, europium (III) and terbium (III) chlorides. The dispersion of the permittivity and the presence of maxima, corresponding to losses, were revealed, which indicates that relaxation processes of various natures were present. The membrane layers under investigation are characterized by relaxation parameters that correspond to a symmetrical distribution of relaxers over relaxation times. The spectrum of relaxers changed when terbium and europium metal impurities were introduced into the polymer matrix. The investigation of these polymer systems demonstrated a power-law dependence of the specific conductivity on frequency. A decrease in the exponent with increasing temperature indicates the existence of a traditional hopping mechanism for charge transfer. The observed changes in the dielectric permittivity and specific conductivity are due to a change in the nature of polarization processes because of the strong interaction of metal (terbium and europium) ions with the polymer matrix of Nafion.

Preparation, Structure, and Photophysical Behavior of Europium (III) Complexes of Decyl Alanine and Lauryl Alanine

Two Ligands (H (dec-ala) and H (dod-ala)) prepared from decyl chloride, lauroyl chloride, and amino acids (DL-alanine), reacted with Europium chloride in methanol solution, leading to two Europium (III) complexes of Eu (dec-ala)3 and Eu (dod-ala)3.Elemental analysis, NMR, and FT-IR spectra proved the elemental content, structural information of the synthesized Europium (III) complexes. The light absorption and luminescence properties were characterized by UV-vis and PL spectra analysis. Both complexes have excellent absorption capacity in the range of 200 nm-300 nm. The ideal excitation wavelengths of these complexes are at 394 nm, and the principal emission peaks are at 590 nm, 610 nm, 650 nm, and 698 nm, which correspond to 5D0 → 7F1, 5D0 →7F2, 5D0→7F3, 5D0→7F4, respectively.

A sole organic hybrid europium(Ⅲ) chloride as a luminescent sensor for Cu2+ ion

The exploration of an outstanding sensor for selectively and sensitively detecting ion is of great significance, because its deficiency or excess from the normal amount has pernicious effect on the human body. Herein, the optically active 2,4,6-tri(2-pyridyl)− 1,3,5-triazine (TPTZ) was utilized for the construction of a new type of organic hybrid europium(Ⅲ) chloride [Eu2(TPTZ)2(pica)Cl5]·2H2O (1, Hpica = pyridine-2-carboxylic acid), which shows a characteristic red-light emission. The quantum efficiency of 1 diluted in anhydrous acetonitrile is 67.28% at room temperature, and obviously higher than that of solid‐state sample (only 19.41%), suggesting that acetonitrile instead of H2O molecule with –OH oscillator may reduce non‐radiative de‐excitation. Owing to the existence of free triazinyl and pyridyl sites serving as the receptors, 1 displays a remarkable sensing property towards Cu2+ ion in acetonitrile solution with a higher Ksv value of 1.85 × 105 M−1 and lower detection limit of 0.97 ppm. Although some luminescent hybrid europium(Ⅲ) chlorides are emerged to date, they have been not served as a luminescent sensor for monitoring Cu2+ ion. Therefore, 1 presents the sole case of hybrid europium(Ⅲ) chloride as a luminescent sensor for the detection of Cu2+ ion.

Pursuit of the Ultimate Regression Model for Samarium(III), Europium(III), and LiCl Using Laser-Induced Fluorescence, Design of Experiments, and a Genetic Algorithm for Feature Selection.

Laser-induced fluorescence spectroscopy, Raman scattering, and partial least squares regression models were optimized for the quantification of samarium (0-150 μg mL-1), europium (0-75 μg mL-1), and lithium chloride (0.1-12 M) with a transformational preprocessing strategy. Selecting combinations of preprocessing methods to optimize the prediction performance of regression models is frequently a major bottleneck for chemometric analysis. Here, we propose an optimization tool using an innovative combination of optimal experimental designs for selecting preprocessing transformation and a genetic algorithm (GA) for feature selection. A D-optimal design containing 26 samples (i.e., combinations of preprocessing strategies) and a user-defined design (576 samples) did not statistically lower the root mean square error of the prediction (RMSEP). The greatest improvement in prediction performance was achieved when a GA was used for feature selection. This feature selection greatly lowered RMSEP statistics by an average of 53%, resulting in the top models with percent RMSEP values of 0.91, 3.5, and 2.1% for Sm(III), Eu(III), and LiCl, respectively. These results indicate that preprocessing corrections (e.g., scatter, scaling, noise, and baseline) alone cannot realize the optimal regression model; feature selection is a more crucial aspect to consider. This unique approach provides a powerful tool for approaching the true optimum prediction performance and can be applied to numerous fields of spectroscopy and chemometrics to rapidly construct models.

A New Method for the Synthesis of Layered Europium Hydroxide Using Propylene Oxide as the Precipitating Agent

A new method for the synthesis of layered europium basic chloride in up to 90% yield was developed. The method is based on hydrolysis of europium chloride in the presence of propylene oxide. The effect of reaction temperature on the yield and composition of the products of europium chloride hydrolysis in the presence of propylene oxide was analyzed. The obtained layered europium basic chloride had pronounced anion exchange properties. The possibility of intercalation of the isonicotinate anion into a layered rare earth hydroxide was demonstrated for the first time. The intercalation of the benzoate or isonicotinate anions into layered europium hydroxide led to luminescence sensitization and decrease in the Eu3+ local symmetry.

Detection of Indigo Carmine dye in juices via application of photoluminescent europium-doped carbon dots from tannic acid.

Indigo Carmine is a hazardous dye and produces an allergic action for humans despite the excessive use of the dye in several industrial fields. A sensitive and simple fluorescent assay for determining Indigo Carmine relying on quenching of the fluorescent europium-doped carbon dots by the action of inner filter effect was developed. This sensing platform involved the preparation of europium-doped carbon dots from the hydrothermal carbonization of tannic acid and europium chloride, which was used as fluorescent reagent with a distinctive excitation/emission wavelength at 307/340 nm. Both excitation and emission fluorescence of prepared carbon dots can be successfully quenched by adding Indigo Carmine dye. The developed spectrofluorimetric method exhibits good linearity with the concentration of Indigo Carmine dye in the range of 1.5 to 10.0 μg/ml and provided a limit of detection (LOD) value of 0.40 μg/ml. Furthermore, the prepared carbon nanoparticles were identified and characterized by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier-transform infrared (FTIR), and ultraviolet (UV)-spectrophotometer techniques. In addition, the developed detecting approach was applied to determine Indigo Carmine in juice samples with acceptable recovery.

Additive effect of lanthanide compounds into perovskite layer on photovoltaic properties and electronic structures

Fabrication and characterization of lanthanide compound doped CH3NH3PbI3 (MAPbI3) perovskite solar cells have been performed for improving the photovoltaic properties with long-term stabilities of conversion efficiency. The purpose of this research is to investigate additive effect of formamidinium iodine (FAI) and lanthanide compound into the perovskite layer for improving carrier diffusion and mobility in the perovskite layer. Incorporation of FAI and europium chloride (EuCl2) into the perovskite crystals maintained the stability of conversion efficiency for 30 days. The photovoltaic properties were based on the crystal growth and orientation with suppression of decomposition, thermodynamic stabilities, and the narrow band dispersion with decrease of effective mass. In contrast case, addition of samarium or terbium compound reduced the stabilities, and suppressed the carrier mobility owing to the flat band dispersion of localized d orbital of samarium atom or 4 f orbital of terbium atom near valence band state. The annealing treatment improved the crystal orientation related to the carrier diffusion with inhibiting recombination, improving short circuit current density and external quantum efficiency. The perovskite crystal doped with EuCl2 and FAI have high advantage to apply for practical use of the photovoltaic devices with long-term stability.

The Role of Temperature on the Degree of End-Closing and Filling of Single-Walled Carbon Nanotubes.

Carbon nanotubes (CNTs), owing to their high surface area-to-volume ratio and hollow core, can be employed as hosts for adsorbed and/or encapsulated molecules. At high temperatures, the ends of CNTs close spontaneously, which is relevant for several applications, including catalysis, gas storage, and biomedical imaging and therapy. This study highlights the influence of the annealing temperature in the range between 400 and 1100 °C on the structure and morphology of single-walled CNTs. The nitrogen adsorption and density functional theory calculations indicate that the fraction of end-closed CNTs increases with temperature. Raman spectroscopy reveals that the thermal treatment does not alter the tubular structure. Insight is also provided into the efficacy of CNTs filling from the molten phase, depending on the annealing temperature. The CNTs are filled with europium (III) chloride and analyzed by using electron microscopy (scanning electron microscopy and high-resolution transmission electron microscopy) and energy-dispersive X-ray spectroscopy, confirming the presence of filling and closed ends. The filling yield increases with temperature, as determined by thermogravimetric analysis. The obtained results show that the apparent surface area of CNTs, fraction of closed ends, and amount of encapsulated payload can be tailored via annealing.

Influence of Europium & Europium complex Eu (TTA)3phen on luminescence properties of electro spun polymer nanofibers.

The europium ion (Eu3+) is well acknowledged and more popular for its strong luminescence when it is compared with other RE ions. Here we report the comparative study of electrospun polymer nanofibers by using europium and europium complex Eu(TTA)3phen by electrospinning technique. Electrospun fibers of Europium chloride and Europium complex Eu(TTA)3phen were prepared by using polymer PVDF to study the photoluminescence properties. Photoluminescence spectra of these electrospun nanofibers show very high intense red emission because of the strong hypersensitive behaviour of the 5D0 → 7F2 transition. These electrospun nanofibers are very much useful in the latest technology of Smart Textiles, for developing protective fabrics with thermal comfort. These fabrics also used to defend from wide variety of environmental hazards. This paper highlights the promising applications of electrospinning for developing protective fabrics and also shows the potential application in various polymer optoelectronic devices.

Characterizations and photo-physical properties of synthesized Europium(III) and Terbium(III) complexes with mercapto-triazole Schiff base ligands

Europium (III) and Terbium (III) complexes of types [Eu(L)Cl(H2O)3] and [Tb(L)OAc(H2O)3] (H2L = Schiff base derived from condensation of 3-(phenyl/substituted phenyl)-4-amino-5-mercapto-1,2,4-triazole with benzil/diacetyl) have been synthesized by the reactions of anhydrous europium (III) chloride and anhydrous terbium (III) acetate with Schiff bases in ethanol. The synthesized complexes were characterized on the basis of elemental analysis, spectroscopic measurement, magnetic moment, electrical conductance and X-ray diffraction studies. The photoluminescence properties of europium (III) and terbium (III) complexes have also been studied. Europium (III) and Terbium (III) complexes show very strong characteristic emission in red and green regions, respectively.

Synthesis and photoluminescence properties of the Eu(III)-containing silica nanoparticles via a mechanochemical solid-state reaction between SiO2 and EuCl3·6H2O

In this study, Eu3+-containing amorphous silica nanoparticles and Eu compounds were successfully synthesized via a mechanochemical solid-state reaction between silica nanoparticles and EuCl3·6H2O. This reaction was induced by a grinding process, and the states of Eu3+ in the silica/europium composites were investigated. The silica/europium composites exhibited orange–red color luminescence owing to the 5D0–7F0, 5D0–7F1, and 5D0–7F2 transitions, which indicated the presence of Eu3+ in the silica framework and the newly formed Eu compounds such as EuOCl and Eu(OH)2Cl. The mechanochemical reaction because of the grinding process effectively induced an interaction between the silica surface and europium chloride; subsequently, Eu(OH)2Cl was formed in the silica/europium composites. Additionally, the Eu(OH)2Cl in the silica/europium composite exhibited a higher thermal stability than that of simple Eu(OH)2Cl, indicating that the mechanochemical reaction mediated the formation of Eu(OH)2Cl and new chemical bonding between the newly formed Eu(OH)2Cl and the silica surface, providing improved thermal stability to Eu(OH)2Cl. Thus, we successfully prepared silica nanoparticles containing not only Eu(III) in the silica framework but also Eu compounds that exhibit unique chemical bonding during a mechanochemical reaction.

A Rare Example of Discrete Lanthanide–Lithium Tetrakis-β-Diketonates: Synthesis, Structures, and Luminescence Properties

The reactions of functionalized lithium CF3-β-diketonate (LiL) with europium(III) and terbium(III) chlorides in acetonitrile afford heterobimetallic complexes with the general formula [LiL-nL4(H2O)](CH3CN) (Ln = Eu (IIIa) and Tb (IIIb)). It is found that Ln–Li tetrakis-β-diketonates can also be prepared by the crystallization from acetonitrile of the previously synthesized complexes [(LnL3)(LiL)(MeOH)] (I) and [(LnL3)(LiL)(H2O)] (II). For the first time, the single crystals of the compounds in a series of Ln–Li tetrakis-β-diketonates are characterized by X-ray diffraction analysis (CIF files CCDC nos. 1973632 (IIIa) and 1973633 (IIIb)). The photoluminescence properties of the synthesized heterometallic complexes in the solid state are studied.

Highly Luminescent and Anti-Photobleaching Core-Shell Structure of Mesoporous Silica and Phosphatidylcholine Modified Superparamagnetic Iron Oxide Nanoparticles.

Highly fluorescent magnetic nanoparticles (Eu(TTA)3(P(Oct)3)3@mSiO2@SPION) [europium (III) chloride hexahydrate = Eu; 4,4,4-trifluoro-1-(2-thienyl)-1,3-butanedione = TTA; trioctylphosphine = (P(Oct)3); mesoporous silica = mSiO2; superparamagnetic iron oxide nanoparticle = SPION] were developed as a dual-functional imaging agent. The hierarchical structure was composed of a magnetic core and mesoporous silica shell was constructed using a cationic surfactant template after coating with phosphatidylcholine of oleic acid coated SPION. Afterward, the surface and cavities of mSiO2@SPION were modified with 3-(trimethoxysilyl) propyl methacrylate (TMSPMA) as a silane coupling agent to introduce methacrylate groups. Eu(TTA)3(P(Oct)3)3 molecules are penetrated, located and bonded covalently inside of the cavities/mesopores of mSiO2, it shows extremely stable anti-photobleaching properties. The emission spectra of Eu(TTA)3(P(Oct)3)3@mSiO2@SPION indicated typical hypersensitivity transition 5D0→7F2 at 621 nm. The concentration of Eu(TTA)3(P(Oct)3)3@mSiO2@SPION was varied between 10 and 500 μL/mL to evaluate the cytotoxicity with NCI-H460 (H460) cells using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. In addition, the presence of a strong red-emitting Eu(TTA)3(P(Oct)3)3@mSiO2@SPION in the cytoplasm was observed by fluorescence microscopy. Those results that it can be a potential candidate for dual-functional contrast agent and PL nanomaterials for fabricating the diagnostic kits to amplify the low signal.

Synthesis and characterization of fluorescent Europium (III) complex based on D-dextrose composite for latent fingerprint detection

A europium salt-Na[Eu(5,5′-DMBP)(phen)3]·Cl3 (Eu(III)-CPLx) was prepared by using various precursors such as 5,5′-Dimethyl-2,2′-bipyridyl (5,5′-DMBP), 1,10-phenanthroline (phen) and europium chloride hexahydrate (EuCl3·6H2O) by a complexation method. The red emission fluorescent Na[Eu(5,5′-DMBP)(phen)3]·Cl3/D-Dextrose (Eu(III)-CPLx/D-Dex) composite was synthesized by using an adsorption method with Eu(III)-CPLx and D-Dextrose (D-Dex). The Eu(III)-CPLx and fluorescent (Eu(III)-CPLx/D-Dex) composites were characterized by numerous techniques. The fluorescent (Eu(III)-CPLx/D-Dex) composite demonstrated a strong red emission and controlled fluorescence quenching in the solid state and was consequently used in latent fingerprint (LFP) detection. The LFPs were developed by using a powder dusting method (PDM) with Eu(III)-CPLx and fluorescent Eu(III)-CPLx/D-Dex composites on different substrates under daylight and UV-light irradiation at 365 nm. The fluorescent Eu(III)-CPLx/D-Dex composite was effectively explored for developing LFP images on various substrates and also acts as a better labeling agent for LFP detection in forensic science crime scene investigations.

Complex Formation of Europium(III) with Photoditazine According to Luminescence and IR Spectroscopy

Europium(III) complexation with photoditazine, a photosensitizer for photodynamic therapy, was studied using luminescence and IR spectroscopy. The luminescence spectra of europium–photoditazine solutions and solid complex show emission bands in the 400–700 nm range, typical of both Eu3+ complexes and photoditazine. It was shown that Eu3+ luminescence intensity in the red region increases upon complex formation with photoditazine. Since the luminescence bands of solutions at 400–700 nm overlap with photoditazine absorption bands, the addition of europium chloride enhances the excitation energy transfer to photoditazine. A medication comprising a europium salt and photoditazine as a photosensitizer could serve for the targeted delivery of light radiation to photoditazine at UV excitation, which would result in more efficient formation of reactive oxygen species and can be promising for external photodynamic therapy.

Lanthanide Complexes Based on 1,3-Dimethylimidazolium-4-Carboxylate: Syntheses and Structures

The reactions of the norzoanemonine zwitterion, 1,3-dimethylimidazolium-4-carboxylate (L), with praseodymium(III), samarium(III), and europium(III) chlorides afford crystals of two types: the isostructural binuclear complexes [Ln2(μ-C6H8N2O2)4(HOCH3)4(H2O)4]Cl6 (Ln = Pr(III) (I) and Eu(III) (II)) and the dimeric samarium complex [Sm2(μ-C6H8N2O2)4(C6H8N2O2)2(H2O)5(OCH3)]Cl5 (III), which are characterized by X-ray diffraction analysis and IR spectroscopy. In complexes I–III (CIF files CCDC nos. 1912829 (I), 1912830 (II), 1912831 (III), the metal atoms are bound by four bridging L molecules without forming the metal–metal bond (the M···M distances are 4.595 A in I, 4.4637 A in II, and 4.584 A in III).

Structural Properties and Luminescence Characteristics of Eu3+ Doped Lithium Triborate (LiB₃O5) Phosphors.

Lithium triborate LiB₃O5:Eu has been prepared by precipitation assisted high-temperature solid state (PAS) reaction method using lithium hydroxide (LiOH), boric acid (H₃BO₃) and europium chloride (EuCl₃). The as prepared powders were calcined at various temperatures. As prepared and calcined powders were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectrometry (EDS), UV-Vis spectrometry and Photoluminescence (PL). The XRD profiles of the powder products revealed the presence of crystalline phase at 650 °C. Increasing bandgap with increasing dopant concentration was studied by UV-Vis spectra. The effect of dopant concentration on photoluminescence properties of LiB₃O5 was also studied. The optimized Eu3+ dopant concentration for potential luminescent LiB₃O5 phosphor was 0.25 mol%.

(Invited) Differences in Emission Properties for Triboluminescent EuD4tea Synthesized Using Both Europium Nitrate or Europium Acetate

Europium tetrakis dibenzoylmethide triethylammonium (EuD4TEA) is one of the most intense triboluminescent (TL) materials currently known. Some time ago, the authors reported that the triboluminescent yield was increased by 82% by changing the starting europium salt from europium chloride to europium nitrate. Unfortunately, europium nitrate has been classified as a hazardous material that cannot be shipped by air, which limits the availability of manufacturers and increases the cost. In an effort to further reduce the synthesis cost of EuD4TEA, we explore the effects of europium acetate on the triboluminescent properties of EuD4TEA by comparing the triboluminescent yield. The photoluminescent spectra as well as crystal structure using an optical microscope will also be explored