Europium Nitrate Research Articles

Determination of Dipicolinic Acid through the Antenna Effect of Eu(III) Coordination Polymer.

Bacillus anthracis is a Gram-positive bacterium that can cause acute infection and anthracnose, which is a serious concern for human health. Determining Bacillus anthracis through its spore biomarker dipicolinic acid (DPA) is crucial, and there is a strong need for a method that is rapid, sensitive, and selective. Here, we created Eu(III)-coordination polymers (Eu-CPs) with surfaces that have abundant carboxyl and hydroxyl groups. This was achieved by using citric acid and europium nitrate hexahydrate as precursors in a straightforward one-pot hydrothermal process. These Eu-CPs were then successfully utilized for highly sensitive DPA determination. The fluorescence (FL) emission of Eu-CPs, which is typically weak due to the coordination of Eu(III) with water molecules, was significantly enhanced in the presence of DPA. This enhancement is attributed to the competitive binding between DPA's carboxyl or hydroxyl groups and water molecules. As a result, the absorbed energy of DPA, when excited by 280 nm ultraviolet light, is transferred to Eu-CPs through an antenna effect. This leads to the emission of the characteristic red fluorescence of Eu3+ at 618 nm. A strong linear relationship was observed between the enhanced FL intensity and DPA concentration in the range of 0.5-80 μM. This relationship allowed for a limit of detection (LOD) of 15.23 nM. Furthermore, the Eu-CPs we constructed can effectively monitor the release of DPA from Bacillus subtilis spores, thereby further demonstrating the potential significance of this strategy in the monitoring and management of anthrax risk. This highlights the novelty of this approach in practical applications, provides a valuable determination technique for Bacillus anthracis, and offers insights into the development cycle of microorganisms.

A novel strategy for the synthesis of samarium/europium-metal organic frameworks, and their utilization for detection of Cr3+, Pb2+, and acetone as a luminescent sensor with superior selectivity and sensitivity properties

With outstanding detection selectivity and sensitivity characteristics, samarium/europium-metal organic frameworks (Sm/Eu-MOF) is capable of functioning as a versatile light-emitting sensor particularly for detecting acetone, Cr3+, and Pb2+ in aqueous environment. While considering maximum detectable concentrations of 0.85 μM, 0.46 μM, and 1.04 μM, respectively, competitive energy interactions for acetone, absorption of energy for Cr3+, and substitution of ions for Pb2+ are the elucidated mechanisms of detecting these substances by Sm/Eu-MOF. Successful formulation and synthesis of a core–shell structured Sm/Eu-MOF, which has endurance to acid/alkali conditions and hydration/heat-stability, can be accomplished by utilizing Samarium and Europium nitrate ions, terephthalic acid, and 2, 5-furandicarboxylic acid. The recovery rate of acetone, Cr3+, and Pb2+ detection from real samples were 95.0–101.0 %, 99.8–101.0 %, and 99.9–104.0 %, respectively.

Synthesisation of Photo-Mechanoluminescence Crystal of Europium Dibenzoylmethide Triethylamine (EuD4TEA) with Different Solvent

EuD4TEA crystals have a few fascinating properties, such as photoluminescence and mechanoluminescence. Both phenomena occur when external excitation is performed on EuD4TEA crystals. Photoluminescence is excited by external light radiation, whereas mechanoluminescence is stimulated by an external mechanical force applied to it. EuD4TEA has easily been prepared only by standard crystallisation using dibenzoylmethane, europium nitrate hexahydrate, and triethylamine. This research mainly focused on the solvent for the synthesis of EuD4TEA crystals. The solvents used were ethanol and acetone. Acetone has the main credit for producing much higher-quality EuD4TEA crystals in certain aspects. Acetone-based end products are larger and have higher light emission under excitation.

Metadynamics investigation of lanthanide solvation free energy landscapes and insights into separations energetics.

Lanthanide ion solvation chemistry in nonaqueous phases is key to understanding and developing effective separation processes for these critical materials. Due to the complexity and inherent disorder of the solution phase, a comprehensive picture of the solvated metal ion is often difficult to generate solely from conventional spectroscopic approaches and electronic structure calculations, particularly in the extractant phase. In this work, we use classical molecular dynamics (MD) simulation with an advanced sampling technique, metadynamics, supplemented by experimental spectroscopy and speciation analysis, to measure lanthanide solvation free energy landscapes. We define coordination-based collective variables to probe the entire range of solvation configurations in the organic phase of lanthanum (La), europium (Eu), and lutetium (Lu) nitrate salts bound with a commonly used extractant, N,N'-dimethyl, N,N'-dioctylhexylethoxymalonamide (DMDOHEMA). The known lanthanide extraction trend of La ≈ Eu > Lu is readily explained by the measured free energy surfaces, which show consistent DMDOHEMA coordination from La to Eu, followed by loss of DMDOHEMA coordination from Eu to Lu. These simulations suggest how ligand crowding at the metal center can control selectivity, in this case resulting in the opposite extraction trend as observed with other conventional extractants, where the enthalpic contribution from increasing lanthanide charge density across the series dominates the extraction energetics. We also find that the presence of inner-sphere water, verified by time-resolved fluorescence, diversifies the accessible solvation structures. As a result, understanding solvation requires consideration of an entire thermodynamic ensemble, rather than the single dominant lowest-energy structure, as is often considered out of necessity in interpretation of spectroscopic data or in electronic structure-based ligand design approaches. In general, we demonstrate how metadynamics uniquely enables investigation of complex, multidimensional solvation energetic landscapes, and how it can explain selectivity trends where extraction is controlled by more complex mechanisms than simple charge density-based selectivity.

Ratiometric fluorescence sensor based on europium-organic frameworks for selective and quantitative detection of cerium ions

BackgroundDue to the unavoidable use of cerium in daily life, the accumulation of cerium in the environment increases health risks for humans. Therefore, it is crucial to develop a chemical sensing technology for the rapid, sensitive, and selective detection of cerium ions. ResultsIn this research work, a novel two-dimensional chain structure of a europium-based metal organic framework (Eu-MOF) [Eu2(tcpa)(Htcpa)2] was synthesized by using 3,4,5,6-tetrachloro-1,2-benzenedicarboxylic acid (H2TCPA) as the ligand and europium nitrate as the metal source. The results of powder X-ray diffraction and thermogravimetric analysis show that the synthesized Eu-MOF has excellent chemical and thermal stability. When the Eu-MOF suspension was excited by ultraviolet light at 292 nm, four fluorescence emissions were observed at 420, 595, 620 and 705 nm. It was particularly interesting that when cerium ions (Ce3+/Ce4+) were added to the Eu-MOF suspension, the fluorescence intensity at 420 nm was enhanced, while the fluorescence at 620 nm was quenched. On this basis, a ratiometric fluorescent sensor for detecting cerium ions was constructed, which has a good linear relationship in the range of 0.05–15 μM and a detection limit of 16 nM. The plausible mechanism of the change in the fluorescence characteristics of Eu-MOF caused by cerium ions was discussed in detail. Through the study of fluorescence lifetime and ultraviolet absorption, it was proven that the mechanism of Ce3+-quenching Eu-MOF fluorescence is the inner filter effect. Photoinduced electron transfer and internal filtering effects lead to fluorescence quenching at 620 nm, while redox reactions lead to fluorescence enhancement of the ligand at 420 nm. SignificanceThe proposed ratiometric fluorescence sensor was successfully employed for the detection of cerium ions in real water samples, confirming that it can be used as an alternative method for the detection of Ce3+ and Ce4+ in environmental samples.

Corrosion resistance of fluorescent carbon fiber reinforced FEVE and fluorescence detection of coating surface

Fluorocarbon resin coating plays a significant role in marine severe corrosion protection. However, seawater has a great influence on the corrosion rate of materials, so it is necessary to strengthen the monitor of marine materials during service. In this study, using solvothermal method, the rare earth (RE) europium nitrate, 1.10-phenoline and concentrated nitric acid oxidized carbon fiber (CF) were chemically doped in the reactor to prepare a kind of carbon fiber with fluorescent characteristics. Then, the RE modified CF was mechanically mixed with fluorocarbon resin to prepare a fluorescent indicator anti-corrosive coating with intrinsic red light emission guided by Eu3+ ultra-sensitive electric dipole transition (5D0→7F2). The correlation between corrosion time and fluorescence spectroscopy could be established to detect the corrosion resistance of the coating, it provides a reference for the anti-corrosion intelligent indication of the coating.

Ratiometric fluorescence probe constructed using metal–organic frameworks and nitrogen-doped carbon dots for specific detection of adenosine monophosphate

The selective detection of adenosine monophosphate (AMP) is of great significance for the study of cellular energy metabolism. In this study, a ratiometric fluorescent probe was designed based on europium-based metal–organic frameworks (Eu-MOF) and nitrogen-doped carbon dots (CDs) that could specifically recognize AMP. Europium nitrate and Disodium Terephthalate (Na2BDC) were used to synthesize Eu-BDC with red fluorescence. The fluorescence of the Eu-BDC was effectively suppressed due to water molecules coordinating with the Eu3+. However, the addition of AMP resulted in a significant restoration of the fluorescence of Eu-BDC, while the fluorescence remained suppressed upon addition of adenosine diphosphate (ADP) and adenosine triphosphate (ATP). We developed a ratiometric fluorescence sensor that could accurately detect AMP by utilizing the blue fluorescence emitted from CDs as a reliable reference signal. Under optimal conditions, the Eu-BDC/CDs system for AMP detection exhibited a linear detection range of 1.0–80.0 μmol/L and a low limit of detection (LOD) of 0.25 μmol/L. The method displayed simple preparation, high selectivity and low cost for AMP detection. To our knowledge, this is the first highly-specify double-response biosensor for AMP.

Combustion synthesis of Eu2O3 nanomaterials with tunable phase composition and morphology

Combustion reactions in europium nitrate – acetylacetone – 2-methoxyethanol solutions and gels were investigated to produce europium (III) oxide (Eu2O3) nanocrystalline materials and thin films. Thermal analyses of solutions indicated that the 2-methoxyethanol solvent also acts as a fuel in the absence of acetylacetone. Adding acetylacetone increases the overall heat of the reaction. Thermal analysis results revealed that the slow oxidation of unburned hydrocarbon residues follows the primary combustion reaction. Time-temperature profile measurements of the bulk combustion synthesis process in air and nitrogen atmospheres enabled the extraction of the maximum reaction temperature and the heating and cooling rates in the combustion zone. Several direct correlations exist between measured combustion parameters and the phase composition of the products. Combustion in air results in mixed-phase cubic and monoclinic nanocrystalline Eu2O3. Increasing the acetylacetone concentration in solutions increases the synthesis temperature and decreases the quantity of cubic Eu2O3. The reaction of solutions in a nitrogen atmosphere or diluted with Eu2O3 provides control of the product phase composition and reduces the quantity of the monoclinic phase. Transmission electron microscopy imaging shows that the Eu2O3 end products are highly porous aggregates of nanocrystalline particles. Electrospraying of reactive solutions onto different substrates followed by short annealing makes the preparation of Eu2O3 materials with diverse morphologies possible.

Highly Luminescent Lanthanide Metal‐Organic Frameworks with Tunable Color for Nanomolar Detection of Iron(III), Ofloxacin and Gossypol and Anti‐counterfeiting Applications

AbstractSolvothermal reaction of 5,5′‐(pyridine‐2,6‐diylbis(oxy))diisophthalic acid (H4L) with europium(III) or terbium(III) nitrates in acetonitrile‐water (1 : 1) at 120 °C gave rise to isostructural 2D coordination polymers, [Ln(HL)(H2O)3]∞ (NIIC‐1‐Eu and NIIC‐1‐Tb), the layers of which are composed by eight‐coordinated lanthanide(III) ions interconnected by triply deprotonated ligands HL3−. The layers are packed in the crystal without any specific intermolecular interactions between them, allowing the facile preparation of stable water suspensions, in which NIIC‐1‐Tb exhibited top‐performing sensing properties through luminescence quenching effect with exceptionally low detection limits towards Fe3+ (LOD 8.62 nM), ofloxacin (OFX) antibiotic (LOD 3.91 nM) and cotton phytotoxicant gossypol (LOD 2.27 nM). In addition to low detection limit and high selectivity, NIIC‐1‐Tb features fast sensing response (within 60–90 seconds), making it superior to other MOF‐based sensors for metal cations and organic toxicants. The photoluminescence quantum yield of NIIC‐1‐Tb was 93 %, one of the highest among lanthanide MOFs. Mixed‐metal coordination polymers NIIC‐1‐EuxTb1−x demonstrated efficient photoluminescence, the color of which could be modulated by the excitation wavelength and time delay for emission monitoring (within 1 millisecond). Furthermore, an original 2D QR‐coding scheme was designed for anti‐counterfeiting labeling of goods based on unique and tunable emission spectra of NIIC‐1‐Ln coordination polymers.

Highly Luminescent Lanthanide Metal-Organic Frameworks with Tunable Color for Nanomolar Detection of Iron(III), Ofloxacin and Gossypol and Anti-counterfeiting Applications.

Solvothermal reaction of 5,5'-(pyridine-2,6-diylbis(oxy))diisophthalic acid (H4 L) with europium(III) or terbium(III) nitrates in acetonitrile-water (1 : 1) at 120 °C gave rise to isostructural 2D coordination polymers, [Ln(HL)(H2 O)3 ]∞ (NIIC-1-Eu and NIIC-1-Tb), the layers of which are composed by eight-coordinated lanthanide(III) ions interconnected by triply deprotonated ligands HL3- . The layers are packed in the crystal without any specific intermolecular interactions between them, allowing the facile preparation of stable water suspensions, in which NIIC-1-Tb exhibited top-performing sensing properties through luminescence quenching effect with exceptionally low detection limits towards Fe3+ (LOD 8.62 nM), ofloxacin (OFX) antibiotic (LOD 3.91 nM) and cotton phytotoxicant gossypol (LOD 2.27 nM). In addition to low detection limit and high selectivity, NIIC-1-Tb features fast sensing response (within 60-90 seconds), making it superior to other MOF-based sensors for metal cations and organic toxicants. The photoluminescence quantum yield of NIIC-1-Tb was 93 %, one of the highest among lanthanide MOFs. Mixed-metal coordination polymers NIIC-1-Eux Tb1-x demonstrated efficient photoluminescence, the color of which could be modulated by the excitation wavelength and time delay for emission monitoring (within 1 millisecond). Furthermore, an original 2D QR-coding scheme was designed for anti-counterfeiting labeling of goods based on unique and tunable emission spectra of NIIC-1-Ln coordination polymers.

Characteristics of red emitting boron nitride nanoparticles

Boron nitride (BN) was synthesized by pyrolysis of a molecular precursor prepared by chemical mixing of boric acid (H3BO3) and melamine (C3H6N6) with a small amount of europium nitrate (Eu3+) as luminescent materials. After pyrolysis, the Eu3+ ions were substitutionally incorporated into a B3N3 hexagonal layer of turbostratic BN (t-BN) at a low doping level estimated to be less than 12 × 1018 atoms/cm3. This phenomenon is due to a randomly stacked turbostratic structure rather than a perfectly stacked hexagonal boron nitride (h-BN) structure along the c-axis. The photoluminescence (PL) spectrum of pure BN was detected at 456 nm (blue), and Eu3+-doped BN was detected at 590, 614, 648, and 696 nm (red) by excitation of UV light (λ = 314 nm). The PL intensity improved as the level of Eu3+ addition was increased. However, excessive doping caused the disappearance of the luminescent properties due to the concentration quenching phenomenon. When the synthesized nanoparticle BN phosphor was mixed with a polymer to form a flexible composite, it was shown that it could be applied as a filter to UV-LED.

NiMoO4/Eu6MoO12 composite on foam Ni as electrode material for supercapacitors

By a one-step hydrothermal reaction, NiMoO4/Eu6MoO12 composite supported on nickel foam was successfully synthesized. The properties of the composite were optimized by adjusting the content of europium nitrate in the reactants. The NiMoO4 nanorods array formed on nickel foam was used as structural support, and Eu6MoO12 nanoparticles were added to the surface, increasing the material's specific surface area and the active site.The two chemicals' combined effect made the electrode reaction more reversible. In addition, Eu with variable oxidation states increased the oxygen vacancy and promoted the Faraday reaction. And the formation of Eu6MoO12 also significantly reduced the charge transfer resistance of the composite, it influenced the electrochemical behavior of materials. Electrochemical experiments show that the specific capacity of NiMoO4/Eu6MoO12 is 1184.0 C g−1 at 1 A/g. The energy density of NiMoO4/Eu6MoO12//AC device is 22.34 W h kg−1 when the power density is 749.52 W kg−1. In addition, the device also has a capacity retention rate of 80.2% after 5000 cycles. The material's superior electrochemical performance demonstrates that it has promising future applications in the realm of energy storage.

Experimental synthesis of double perovskite functional nano-ceramic Eu2NiMnO6: Combining optical characterization and DFT calculations

We reported on the synthesis of the pure double perovskite Eu2NiMnO6 in nano ceramic forms by two different methods solvotermal and sol-gel routes without europium and magnesium nitrate. Room temperature X-ray powder diffraction study of the compound revealed a monoclinic P21/n structure. The particle size was determined by the Williamson–Hall and Scherrer formula and found around 43 and 59 nm for the average size. The chemical, homogeneous and optical properties of nanoparticles were confirmed by SEM, UV–vis absorbance and FTIR spectra. The Eu2NiMnO6 has an energy band gap 1.32 eV determined by Heyd-Scuseria Ernzerhof (HSE06) from density-functional theory (DFT) calculations close to the value found experimentally 1.01 eV.

The interaction of triglycidyl phosphate with europium nitrate and properties of obtained metal-containing polymer

The interaction of phosphorus-containing epoxy trifunctional monomer – triglycidyl phosphate (TGPhT), with europium (III) nitrate hexahydrate is studied. A dissolution of europium salt added into TGPhT is occurred due to the interaction of the cation with phosphoryl groups and oxygen atoms of the epoxy ring, that is accompanied by the opening reaction and led to the formation of a polymer. The interaction of triepoxide with salt is investigated by FTIR-spectroscopy and differential scanning calorimetry (DSC). The thermal stability of the samples is determined by combined method of thermogravimetry and differential scanning calorimetry (TG/DSC), coupled with a quadrupole mass spectrometry to identify the gaseous products evolved during the thermal analysis of the samples. The kinetic parameters of the curing reaction are computed by using Thermokinetics software. The interaction of TGPhT with europium nitrate is suggested to occur through opening of epoxy rings in the presence of europium ions via the mechanism of cationic polymerization. The cured epoxy polymer exhibits luminescent properties.

Tribological of Eu-doped WO3 coated with SiO2 transfer film formation on sliding surface

ABSTRACT Europium nitrate, ammonium tungstate and hexadecyl trimethyl ammonium bromide were used, and Eu-doped WO3 (WO3:Eu3+) nanopowder was synthesized by the micro-emulsion method. Tetraethyl silicate was hydrolysed into SiO2 and WO3:Eu3+ nanopowder coated with SiO2 (SiO2/WO3:Eu3+) was obtained. The microstructure and morphology of the prepared nano-SiO2/WO3:Eu3+ powders were characterized by XRD, SEM, TEM and HRTEM. Results showed that the prepared nano-SiO2/WO3:Eu3+ powders composed of WO3 of monoclinic and SiO2 of amorphous, which was spherical and granular, and the grain size reaches 50 nm. The tribological behaviour of nano-SiO2/WO3:Eu3+ as extreme pressure and anti-wear additive in the water-based fluid was studied by a four-ball machine. The results demonstrate that nano-SiO2/WO3:Eu3+ exhibits superior load-bearing capacity, anti-wear and anti-friction performance in water-based fluid, especially when the optimal concentration of nano-SiO2/WO3:Eu3+ is 0.4 wt-%. WSD, COF and wear volume of the nano-SiO2/WO3:Eu3+ decreased by 62.43%, 30.20% and 67.34%, respectively, compared with that of the water-based fluid.

A Flexible Multifunctional PAN Piezoelectric Fiber with Hydrophobicity, Energy Storage, and Fluorescence.

Lightweight, flexible, and hydrophobic multifunctional piezoelectric sensors have increasingly important research value in contemporary society. They can generate electrical signals under the action of pressure and can be applied in various complex scenarios. In this study, we prepared a polyacrylonitrile (PAN) composite fiber doped with imidazolium type ionic liquids (ILs) and europium nitrate hexahydrate (Eu (NO3)3·6H2O) by a facile method. The results show that the PAN composite fibers had excellent mechanical properties (the elongation at break was 114% and the elastic modulus was 2.98 MPa), hydrophobic self-cleaning ability (water contact angle reached 127.99°), and can also emit light under UV light irradiation red fluorescence. In addition, thanks to the induction of the piezoelectric phase of PAN by the dual fillers, the composite fibers exhibited efficient energy storage capacity and excellent sensitivity. The energy density of PAN@Eu-6ILs reached a maximum of 44.02 mJ/cm3 and had an energy storage efficiency of 80%. More importantly, under low pressure detection, the sensitivity of the composite fiber was 0.69 kPa-1. The research results show that this PAN composite fiber has the potential to act as wearable piezoelectric devices, energy storage devices, and other electronic devices.

Raman Spectroscopic Studies on Graphene Oxide – Europium Nano Composites

Graphene based nano composites are receiving much importance in recent years due to the two-dimensional topology, high carrier mobility, luminescent nature, and ultra wide band gap transition. Here graphene oxide is prepared by modified Hammers method. Resultant residue of dark yellow color is filtered using Watt man No. 1 filter paper and is further cleaned by washing several times with 5% HCl solution and de-ionized water. Unexfoliated oxide is eliminated from the sample by ultra-sonication procedure for 30 minutes followed by micro-centrifugation under 4000 rpm for another 30 minutes. Vacuum annealing is done at sample at 60OC for 12 hours to get black graphene oxide powder and is labelled as Sample4. Europium (III) nitrate is added to 3g each of graphene oxide powder in 0.1g, 0.2g, and 0.3g concentration respectively labelled as Sample1, Sample2, and Sample3. Uniform mixing is done in composite samples. Morphological properties are analyzed through SEM. Surface topology of GO is like thin folded sheet, while that of Eu-GO is like that of spreading small nano materials on folded surface. Average particle size distribution is found to be 79.09 nm. Chemical composition and stotiometric ratio of different elements in the composites are quantitatively shown by EDX analysis. Raman spectra for Samples 1, 3, and 4 are shown. We can see that no shifting of peaks are observed in composites with respect to pure GO is an evidence of stable sp2 hybridisation and rigid oxygenated functional groups.

Redox and emission characteristics of Eu3+ in deep eutectic solvent: Unraveling the hidden potential of DES as luminescent media

Pertaining to the importance associated with designing of novel and green solvent for fundamental research as well as technological applications, this work is a step towards similar direction. Herein, we have explored the electrochemical and photophysical investigation of europium nitrate in acidic deep eutectic solvent (DES) with Choline chloride (ChCl) as hydrogen bond acceptor and para toluene sulfonic acid (PTSA) as hydrogen bond donor. Fourier transformed infrared (FTIR) spectroscopy suggested formation of hydrogen bonding in ChCl-PTSA acidic DES. Cyclic Voltammetry (CV) suggested reduction of Eu(III) to Eu(II) is quasi-reversible and is controlled by both diffusion of Eu(III) ion in DES and kinetics of the charge transfer reaction occurring at the electrode-electrolyte inter phase. Temperature dependent CV suggested that diffusion coefficient increases with increase in the temperature owing to the reduction in viscosity of the medium. Thermodynamics measurements postulated that standard entropy change for the redox behavior of Eu(III)/Eu(II) couple in PTSA:ChCl DES is positive which indicates that the reaction happens at the expense of more disorderness in the system. Photoluminescence (PL) spectroscopy suggested that europium ion local symmetry is highly distorted with high asymmetry. Lifetime spectroscopy suggested formation of moderate complex between DES and europium ion with presence of four molecules of water. This results in lower internal quantum efficiency of europium ion in DES. But the positive implication is its multi-wavelength excitability and higher color purity of 5D0→7F2 red emission. We envision that this Eu-DES complex work can be propagated to other lanthanides and system needs to be optimized to achieve higher internal quantum efficiency for it to fetch more commercial attentions.

Single crystal X-ray structure determination and enantiomeric recognition of chiral dinuclear europium (III) complexes towards BINOL

Herein, we reported a pair of di-nuclear europium enantiomers [Eu2(PO4)6(R-/S-HL)6(MeOH)4]•2MeOH (R-complex(1a) and S-complex(1b)) constructed from chiral ligands (R)-/(S)-(+)-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate (R-/S-HL) and europium (III) nitrate by solvothermal method. The structure of the complexes was characterized by single-crystal X-ray diffraction, powder X-ray diffraction and Fourier transform infrared spectroscopy. It was found that R-complex(1a) and S-complex(1b) were chiral enantiomers with a zero-dimensional chiral cluster structure. The circular dichroism studies further revealed the chiral properties of R-complex(1a) and S-complex(1b). Moreover, fluorescence sensing tests demonstrated that R-complex(1a) and S-complex(1b) possessed high enantioselectivity for axially chiral BINOL racemates.

Rare earth doped organic–inorganic hybrid polyhedral oligomeric silsesquioxane phosphors applied for flexible sheet and anti-counterfeiting

We have developed organic–inorganic hybrid polyhedral oligomeric silsequioxane (POSS) type monomer ligand 2,6-pyridinediamine-bis-propanylheptaisobutyl POSS (PDC-POSS) and synthesized rare earth (RE =Eu3+) doped hybrid complex PDC-POSS phosphors. The PDC-POSS precursor was prepared using (3-aminopropyl)heptaisobutyl POSS, 2,6-pyridinedicarboxylic acid chloride (PDC) as the host material, and then coordinated with RE3+ using europium nitrate regents to synthesize PDC-POSS:Eu3+ phosphors. The photoluminescence (PL) spectra of the PDC-POSS:Eu3+ hybrid phosphors were detected at 592, 616, 649, 693 nm under UV light (λ= 288 nm) excitation. In addition, the synthesized hybrid phosphors showed red light emission under UV light. The phosphors were demonstrated on a flexible sheet that could be applied for red emitting LEDs, and for anti-counterfeiting, which requires the film to remain hidden and identifiable only by UV light.