Lanthanide Nitrate Research Articles

Crystal structures of the penta- and hexa-hydrate of thulium nitrate.

Tm(NO3)3·5H2O and Tm(NO3)3·6H2O, or more precisely [Tm(NO3)3(H2O)4]·H2O and [Tm(NO3)3(H2O)4]·2H2O, respectively, have been obtained from a concentrated solution of Tm2O3 in HNO3. The crystal structures of the two hydrates show strong similarities as both crystallize in space group P with all atoms at general positions and contain neutral, mol-ecular [Tm(NO3)3(H2O)4] complexes, i.e. ten-coordinated TmIII cations with three nitrate anions as bidentate ligands and four coordinating water mol-ecules, and one or two additional crystal water mol-ecules, respectively. All building units are connected by medium-strong to weak O-H⋯O hydrogen bonds. Tm(NO3)3·6H2O represents the maximally hydrated thulium nitrate as well as the heaviest rare earth nitrate hexa-hydrate known to date.

Up-converting nanoparticles synthesis using hydroxyl-carboxyl chelating agents: Fluoride source effect.

The synthesis of lanthanide doped up-converting nanoparticles (UCNPs), whose morphological, structural, and luminescence properties are well suited for applications in optoelectronics, forensics, security, or biomedicine, is of tremendous significance. The most commonly used synthesis method comprises decomposition of organometallic compounds in an oxygen-free environment and subsequent infliction of a biocompatible layer on the particle surface. In this work, hydroxyl-carboxyl (-OH/-COOH) type of chelating agents (citric acid and sodium citrate) are used in situ for the solvothermal synthesis of hydrophilic NaY0.5Gd0.3F4:Yb,Er UCNPs from rare earth nitrate salts and different fluoride sources (NaF, NH4F, and NH4HF2). X-ray powder diffraction showed crystallization of cubic and hexagonal NaY0.5Gd0.3F4:Yb,Er phases in nano- and micro-sized particles, respectively. The content of the hexagonal phase prevails in the samples obtained when Na-citrate is used, while the size and shape of the synthesized mesocrystals are affected by the choice of fluoride source used for precipitation. All particles are functionalized with citrate ligands and emit intense green light at 519 nm and 539 nm (2H11/2, 4S3/2 → 4I15/2) under near infrared light. The intensity of this emission is distressed by the change in the origin of phonon energy of the host matrix revealed by the change in the number of the excitation photons absorbed per emitted photon.

Synthesis and Structural Characterization of Some Lanthanide(III) Nitrate Complexes with a Mesogenic Schiff-Base, N,N’-di-4-(4’-heptadecyloxybenzoate) salicylidene-1,3-diaminopropane Derived from 2,4- dihydroxybenzaldehyde

Complexes of La(III), Pr(III), Nd(III), Sm(III), Gd(III) and Dy(III) with the Schiff-base, N,N′-di-4-(4’-heptadecyloxybenzoate)salicylidene-1,3-diaminopropane, (abbreviated as H2L) have been synthesized and characterized on the basis of elemental analyses, molar conductance, magnetic, electronic, infrared, 1H and 13C NMR spectral techniques. The nephelauxetic ratio (β), the bonding parameter (b1/2), Sinha’s parameter (%δ) and angular overlap parameter (η) have been calculated from the electronic spectra of Pr(III), Nd(III), Sm(III) and Dy(III) complexes. Infrared and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as LH2) to the Ln(III) ions through two phenolate oxygens, rendering the overall geometry around Ln(III) to distorted square antiprism. Polarized optical microscopy (POM) and differential scanning calorimetry (DSC) shows the liquid crystalline property of the ligand with a nematic (N) mesophase. Among the metal complexes, only that of the Gd(III) exhibits smectic B (SmB) and nematic (N) phases.

Octanuclear Ni4 Ln4 Coordination Aggregates from Schiff Base Anion Supports and Connecting of Two Ni2 Ln2 Cubes: Syntheses, Structures, and Magnetic Properties.

A family of 3d-4f aggregates have been reported through guiding the dual coordination modes of ligand anion (HL- ) and in situ generated ancillary bridge driven self-assembly coordination responses toward two different types of metal ions. Reactions of lanthanide(III) nitrate (Ln=Gd, Tb, Dy, Ho and Yb), nickel(II) acetate and phenol-based ditopic ligand anion of 2-[{(2-hydroxypropyl)imino}methyl]-6-methoxyphenol (H2 L) in MeCN-MeOH (3 : 1) mixture and LiOH provided five new octanuclear Ni-4f coordination aggregates from two Ni2 Ln2 cubanes. Single-crystal X-ray diffraction analysis reveals that all the members of the family are isostructural, with the central core formed from the coupling of two distorted [Ni2 Ln2 O4 ] heterometallic cubanes [Ni2 Ln2 (HL)2 (μ3 -OH)2 (OH)(OAc)4 ]+ (Ln=Gd (1), Tb (2), Dy (3), Ho (4) and Yb (5)). Higher coordination demand of 4f ions induced the coupling of the two cubes by (OH)(OAc)2 bridges. Variable temperature magnetic study reveals weak coupling between the Ni2+ and Ln3+ ions. For the Tb (2) and Dy (3) analogs, the compounds are SMMs without an applied dc field, whereas the Gd (1) analogue is not an SMM. The observation revealed thus that the anisotropy of the Ln3+ ions is central to display the SMM behavior within this structurally intriguing family of compounds.

Synthesis, Structures, and Magnetic Properties of Zigzag Tetranuclear Lanthanide Complexes

Five isostructural tetranuclear lanthanide complexes with the general formula [Ln4(teaH2)2(teaH)2(NO3)6]·2CH3OH [Ln3+ = Dy3+ (1), Tb3+ (2), Ho3+ (3), Er3+ (4), and Gd3+ (5)] were successfully synthesized by the reaction of various lanthanide nitrate and triethanolamine (teaH3) ligand. Single crystal X‐ray analyses reveal the eight‐coordinate Ln3+ centers adopt a slightly distorted triangular dodecahedron geometry and nine‐coordinate Ln3+ ions own an approximately capped square antiprism environment in similar zigzag Ln4 core. Magnetic studies demonstrate the presence of anitferromagnetic interactions between Ln3+ centers without obvious SMM behavior.

Interphase Distribution of Lanthanide Nitrates in Aqueous Organic Two-Phase Systems with Amine and Organic Acid Salts

The extraction of lanthanide nitrates from 0.5 M NaNO3 solutions in 1 : 1 : 1 ternary aqueous organic systems using mixtures of trioctylammonium dialkyl phosphate and dicyclohexylammonium caprylate as extractants was studied. The extractability of lanthanides was shown to increase in the series La < Pr < Nd, Sm, Eu < Gd < Tb < Dy < Ho < Er < Tm, in which the atomic number of the metal increases. The selectivity of extraction in the ternary system was observed during the extraction of heavy lanthanides.

Airborne Release Fractions from Surrogate Nuclear Waste Fires Containing Lanthanide Nitrates and Depleted Uranium Nitrate in 30% Tributyl Phosphate in Kerosene

Airborne contaminants from fires containing nuclear waste represent significant health hazards and shape the design and operation of nuclear facilities. Much of the data used to formulate DOE-HDBK-3010-94, “Airborne Release Fractions/Rates and Respirable Fractions for Nonreactor Nuclear Facilities,” from the U.S. Department of Energy, were taken over 40 years ago. The objectives of this study were to reproduce experiments from Pacific Northwest Laboratories conducted in June 1973 employing current aerosol measurement methods and instrumentation, develop an enhanced understanding of particulate formation and transport from fires containing nuclear waste, and provide modeling and experimental capabilities for updating current standards and practices in nuclear facilities. A special chamber was designed to conduct small fires containing 25 mL of flammable waste containing lutetium nitrate, ytterbium nitrate, or depleted uranium nitrate. Carbon soot aerosols showed aggregates of primary particles ranging from 20 to 60 nm in diameter. In scanning electron microscopy, ~200-nm spheroidal particles were also observed dispersed among the fractal aggregates. The 200-nm spherical particles were composed of metal phosphates. Airborne release fractions (ARFs) were characterized by leaching filter deposits and quantifying metal concentrations with mass spectrometry. The average mass-based ARF for 238U experiments was 1.0 × 10−3 with a standard deviation of 7.5 × 10−4. For the original experiments, DOE-HDBK-3010-94 states, “Uranium ARFs range from 2 × 10−4 to 3 × 10−3, an uncertainty of approximately an order of magnitude.” Thus, current measurements were consistent with DOE-HDBK-3010-94 values. ARF values for lutetium and ytterbium were approximately one to two orders of magnitude lower than 238U. Metal nitrate solubility may have varied with elemental composition and temperature, thereby affecting ARF values for uranium surrogates (Yb and Lu). In addition to ARF data, solution boiling temperatures and evaporation rates can also be deduced from experimental data.

Trinuclear NiII-LnIII-NiII Complexes with Schiff Base Ligands: Synthesis, Structure, and Magnetic Properties.

The reaction of the Schiff base ligand o-OH-C6H4-CH=N-C(CH2OH)3, H4L, with Ni(O2CMe)2·4H2O and lanthanide nitrate salts in a 4:2:1 ratio lead to the formation of the trinuclear complexes [Ni2Ln(H3L)4(O2CMe)2](NO3) (Ln = Sm (1), Eu (2), Gd (3), Tb (4)). The complex cations contain the strictly linear NiII-LnIII-NiII moiety. The central LnIII ion is bridged to each of the terminal NiII ions through two deprotonated phenolato groups from two different ligands. Each terminal NiII ion is bound to two ligands in distorted octahedral N2O4 environment. The central lanthanide ion is coordinated to four phenolato oxygen atoms from the four ligands, and four carboxylato oxygen atoms from two acetates which are bound in the bidentate chelate mode. The lattice structure of complex 4 consists of two interpenetrating, supramolecular diamond like lattices formed through hydrogen bonds among neighboring trinuclear clusters. The magnetic properties of 1–4 were studied. For 3 the best fit of the magnetic susceptibility and isothermal M(H) data gave JNiGd = +0.42 cm−1, D = +2.95 cm−1 with gNi = gGd = 1.98. The ferromagnetic nature of the intramolecular Ni···Gd interaction revealed ground state of total spin S = 11/2. The magnetocaloric effect (MCE) parameters for 3 show that the change of the magnetic entropy (−ΔSm) reaches a maximum of 14.2 J kg−1 K−1 at 2 K. A brief literature survey of complexes containing the NiII-LnIII-NiII moiety is discussed in terms of their structural properties.

Ultrathin (Y0.98Re0.02)2(OH)5NO3·nH2O (Re= Pr, Sm, Eu, Tb, Dy, Ho, Er, Tm) nanosheets and well-dispersed oxide nanoparticles: Facile co-precipitation synthesis and multi-color luminescent properties

A rapid and mass synthesis of layered rare-earth hydroxide nanosheets with controlled two-dimensional size and thickness via coprecipitation at room temperature was developed. Using this technology, a series of (Y0.98Re0.02)2(OH)5NO3·nH2O (Re= Pr, Sm, Eu, Tb, Dy, Ho, Er and Tm) ultrathin nanosheets were successfully prepared via adjusting the concentration of rare earth nitrate solution and the corresponding well-dispersed oxide nanoparticles (~60 nm) with abundant photoluminescence emissions including blue, green, yellow, orange and red were obtained via direct calcination at 1000 °C.

Controllable phase/morphology tailoring of REF3 and NaREF4 (RE = La-Lu, Y), and insights into the up-conversion luminescence of GdF3:Yb3+/Tm3+ spheres

Four typical rare earth fluorides of hexagonal/orthorhombic REF3 and hexagonal/cubic NaREF4 (RE = La-Lu, Y, excluding radioactive Pm), have been hydrothermally synthesized from mixed solutions of the rare earth nitrate solutions and ammonium fluoride (NH4F), in the presence of EDTA-2Na. The phase and the morphology are closely related to the ionic radius of RE3+. Large RE3+ ions, La3+, Ce3+, Pr3+, Nd3+ and Sm3+, crystallize in hexagonal REF3 (nanocrystals), and middle RE3+ ions (RE = Eu-Dy) crystallize in orthorhombic REF3 (micron-sized spheres/polyhedral micro-crystallites). For small RE3+ ions, Ho3+, Er3+, Tm3+, Yb3+ and Y3+, they tend to being incorporated into the host lattice of cubic NaREF4 (submicron spheres). However, the smallest Lu3+ tends to crystallizing in orthorhombic LuF3. Varying the F-/RE3+ molar ratio (R) and the reaction temperature can efficiently induce the phase/morphology evolution of rare earth fluorides. Increasing R up to 10–30 yielded hexagonal NaREF4 (RE = Dy, Tb, Gd, Eu, Sm, micron prisms), although the original products were orthorhombic REF3 (RE = Dy, Tb, Gd, Eu) and hexagonal SmF3 at R = 5. However, increasing R is inefficient to the phase transition for large RE elements of La, Ce, Pr, Nd. Lowering the reaction temperature from 180 °C to 80 °C gave rise to the phase transition from orthorhombic LuF3 to cubic NaLuF4. GdF3:Yb3+,Tm3+ spheres exhibited intense blue emission at ~476 nm (1G4 → 3H6 transition of Tm3+), deep-red emission at ~646 nm (1G4→3F4 transition of Tm3+), and near-infrared emission at ~695 nm (3F2,3 → 3H6 transitions of Tm3+) under the 980 nm infrared excitation. The intense near-infrared emission under the infrared excitation suggested that they might hold great potential in bio imaging application.

Electrical Conductivity in a Porous, Cubic Rare-Earth Catecholate.

Electrically conductive metal–organic frameworks (MOFs) provide a rare example of porous materials that can efficiently transport electrical current, a combination that is favorable for a variety of technological applications. The vast majority of such MOFs are highly anisotropic in both their structures and properties: Only two electrically conductive MOFs reported to date exhibit cubic structures that enable isotropic charge transport. Here we report a new family of intrinsically porous frameworks made from rare-earth nitrates and hexahydroxytriphenylene. The materials feature a novel hexanuclear secondary building unit and form cubic, porous, and intrinsically conductive structures, with electrical conductivities reaching 10–5 S/cm and surface areas of up to 780 m2/g. By expanding the list of MOFs with isotropic charge transport, these results will help us to improve our understanding of design strategies for porous electronic materials.

Study on synthesis and luminescent properties of Mn4+ doped (Gd,Y)3Al5O12 phosphor

In this paper, a series of Gd2.4Y0.6Al5-xMnxO12 (x = 0.0001–0.003) precursor were synthesized by co-precipitation method using ammonium bicarbonate as precipitant and rare earth nitrate as mother salt solution, following calcined at 1500 °C to obtain resultant phosphor. The garnet lattice stability, microstructure, structural characteristics and fluorescence properties were investigated by FT-IR, XRD, FE-SEM, PL/PLE and fluorescence decay analysis, respectively. The resultant phosphors Gd2.4Y0.6Al5-xMnxO12 (x = 0.0001–0.003) with uniform particle morphology and size display good red emission at ∼677 nm (2E→4A2 transition of Mn4+) under excitation wavelength of 322 nm (4A2→4T1 transition of Mn4+). The quenching concentration of Mn4+ ions were determined to be ∼0.02 at.%, and the quenching mechanism was due to the electric dipole-quadruple interactions. The Ca2+, Mg2+, Sr2+, Ba2+ and Zn2+ doping can significantly enhance the red emission of Mn4+ ions owing to the charge compensation effect. The Gd2.4Y0.6Al5-xMnxO12 (x = 0.0001–0.003) garnet phosphors with good luminescent properties are expected to be widely used in lighting and display areas.

Heterobimetallic [NiIILnIII] (Ln = Sm and Tb) N2O4-donor coordination polymers: Syntheses, crystal structures and fluorescence properties

Through the self-assembly of a 3-EtO salamo H2L with nickel acetate tetrahydrate, lanthanide nitrate hexahydrate (Ln = Sm and Tb) and terephthalic acid (H2bdc), two new heterobimetallic [NiIILnIII] 3d-4f polymers, 2∞[Ni(L)Sm(bdc)1.5]·CH3OH (1) and 1∞[Ni(L)Tb(NO3)(DMF)(bdc)] (2) were synthesized, respectively. Coordination polymers 1 and 2 were characterized via elemental analysis, X-ray single-crystal analysis, IR and UV–visible absorption spectroscopy. Coordination polymer 1 is a 2D coordination polymer in which [Ni(L)Sm] units are linked by exodentate (bdc)2− linker. Coordination polymer 2 is a 1D chain coordination polymer in which the [Ni(L)Tb(NO3)] moieties are connected by exodentate (bdc)2− linker, and they further form a 3D supramolecular configuration through intermolecular hydrogen bondings. Fluorescence properties of coordination polymers 1 and 2 have been discussed.

Multistep synthesis and upconversion luminescence of spherical Gd2O3:Er and Gd2O3:Er @ silica

Spherical Gd2O3:Er3+ and Gd2O3:Er3+ @ silica nanoparticles have been successfully synthesized by a multistep procedure including precipitation and sol–gel processes from rare-earth nitrates, TEOS and urea as starting precursors. The structure, morphology and chemical composition of the products were characterized by X-ray diffraction, field emission scanning electron microscopy, and fourier transform infrared spectroscopy. The results indicated that the obtained phosphors consist of separated, non-agglomerated spheres in nanoscale with an uniform, ideal spherical shape. The suitable amount of TEOS was addressed to obtain the spherical Gd2O3:Er3+ @ silica nanocomposites with the luminescence intensity almost unchanged with respect to the uncoated Gd2O3:Er3+ sample. Besides, the upconversion emission spectra showed intense green and red emission bands under 980-nm laser diode excitation with remarkable increase in the red emissions. The upconversion luminescence followed the two-photon mechanism for green and red emissions. With obtained results, the prepared nanospheres are expected to be a potential material to create functional groups for subsequent bio-conjugation with various biomolecules in medical diagnostics.

Lanthanide Metal-Organic Frameworks as Luminescent Sensor for Toluene

Two new series of lanthanide metal-organic frameworks (LnMOFs) are successfully obtained via a solvothermal reaction, based on the corresponding lanthanide(III) nitrates and the ligand of methylmalonic acid (MMA). Where 1a–1c are synthesized by Ln(NO3)3 (Ln3+ = Eu, 1a; Gd, 1b; Tb, 1c) and MMA, 2a and 2b are obtained with Ln(NO3)3 (Ln3+ = Eu, 2a; Tb, 2b), MAA, and in the presence of capping agent 1,10-phenanthroline (phen). The five new compounds were structurally determined by single-crystal X-ray diffraction, FT-IR, PXRD, TGA and luminescence. Furthermore, the sensing property reveals that 1a is a luminescent sensor for toxic solvent of toluene.

Synthesis, characterization, and thermoanalytical study of aceclofenac of light lanthanides in the solid state (La, Ce, Pr, and Nd)

Lanthanide aceclofenac compounds were synthesized by the addition of lanthanide nitrate aqueous solution to aceclofenac–acetone solution. The compounds obtained in the solid state were characterized by thermal and spectroscopic studies, as well as by complementary x-ray diffraction data. The metal–ligand stoichiometric ratio was defined by simultaneous thermogravimetry and differential scanning calorimetry (TG-DSC) as [Ln(Acec)3·nH2O], where Ln represents the metal centre (La, Ce, Pr, or Nd) and Acec represents the ligand, with n = 4(La), 3(Ce), and 2.5(Pr, Nd). TG-DSC and Fourier transform infrared spectroscopy (FTIR) data also allowed for determination of the thermal behaviour and possible coordination modes between the metal and the ligand.

Structures and Spectral and Magnetic Properties of a Series of Carbacylamidophosphate Pentanuclear Lanthanide(III) Hydroxo Complexes.

A series of pentanuclear lanthanide complexes Ln5L6(μ-L)4(μ3-OH)4(μ4-OH) (LnIII = Nd, Dy, Ho, Er, Yb; L- = dimethyl N-benzoylamidophosphate ion, [C6H5C(O)-N-P(O)(OCH3)2]-) was obtained by the reaction of sodium dimethyl N-benzoylamidophosphate with the corresponding lanthanide nitrates. The pentanuclear cores formed as a result of self-arrangement and their composition did not depend on the lanthanide ion. The complexes and sodium dimethyl N-benzoylamidophosphate have been characterized by single-crystal X-ray diffraction. The absorption spectra of the complexes were measured at 300 and 4 K. The dysprosium and ytterbium complexes exhibited weak emission in the visible and IR regions, respectively. Temperature dependences of magnetic susceptibility (χM) of the dysprosium, holmium, and erbium compounds were studied. It was found that χM vs T dependences were governed by the crystal field splitting effects with the Δ parameter being in the range 5-17 cm-1. Slow magnetic relaxation was found for the dysprosium complex by ac magnetic measurements, while no significant out-of-phase signals were detected for holmium and erbium complexes.

Thermodynamic modeling of the water – Nitric acid – Rare earth nitrate systems

An excess Gibbs energy model describing the properties of aqueous electrolyte solutions, mixed solvent electrolyte systems and nonelectrolyte systems, has been developed. The suggested electrolyte version of the Generalized Local Composition Model (eGLCM) contains three contributions to the excess Gibbs energy: a long–range electrostatic interaction term represented by the modified Pitzer-Debye-Hückel equation, which takes into account concentration dependence of the solution dielectric permittivity, the contribution of the short–range interaction between all the species, represented by the GLCM model, and the middle–range interaction term responsible for interactions involving charged species that are not explained by the long–range term. The developed model is applicable over a whole concentration range, from pure water to saturation and fused salts. The water – nitric acid system, 15 water – rare earth element nitrate systems (Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu) and eight water – nitric acid – REE nitrate systems (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) have been modeled with the proposed electrolyte version of the Generalized Local Composition Model at 25 °C, using experimental data on both the vapor – liquid (VLE) and solid – liquid (SLE) equilibria, in a concentration range from dilute solutions to saturation. SLE data in the ternary systems were critically reviewed and correlated with the thermodynamic properties of the solutions.

A Highly Sensitive and Recyclable Ln-MOF Luminescent Sensor for the Efficient Detection of Fe3+ and CrVI Anions.

Two new three-dimensional (3D) LnIII metal-organic frameworks (MOFs) were designed and successfully obtained via a solvothermal reaction between lanthanide(III) nitrates and a semi-flexible carbazole tetracarboxylate acid linker as a high-performance chromophore. 1 and 2 possess porous 3D networks with channels along the a axis, and more importantly, they show a highly sensitive and selective fluorescence quenching response to Fe3+ and CrVI anions. The sensing mechanism investigation revealed that the weak interactions of Fe3+ with nitrogen atoms of carbazole and deprotonated carboxylic acids protruding into the pores of MOFs quenched the luminescence of 1 and 2 effectively. In addition, the competition absorption also played an important role in the luminescence quenching detection of Fe3+ based on 1, and CrVI anions based on 1 and 2. Therefore, 1 and 2 represent an alternative example of regenerable luminescence based sensors for the quantitative detection of Fe3+ and CrVI anions.

Synthesis, crystal structure, thermal, luminescent property and antibacterial activity of lanthanide ternary complexes with p-chlorobenzoic acid and 5,5′-dimethyl-2,2′-bipyridine

Four novel lanthanide coordination complexes, [La(p-ClBA)3(5,5′-DM-2,2′-bipy)H2O]n (1), [Ln(p-ClBA)3(5,5′-DM-2,2′-bipy)H2O]2 (Ln = Sm 2, Eu 3, Gd 4) were obtained from the reaction between p-chlorobenzoic acid (p-ClHBA), 5,5′-dimethyl-2,2′-bipyridine (5,5′-DM-2,2′-bipy) and lanthanide nitrate under solvothermal conditions. Single crystal X-ray diffraction analysis showed that complex 1 is a 1D chain structure, crystallized in the monoclinic system, space group P2(1)/n, and formed a 2D sheet through the C–H⋯O hydrogen bond interactions. While complexes 2–4 were binuclear unit and crystallizes isomorphically in the triclinic system, space group Pī. The binuclear unit were assembled into 1D supramolecular structures through the O–H⋯O hydrogen bond interactions along the a-axis and formed a 2D supramolecular structures through the π-π stacking interactions along the b-axis. The thermal analysis of four complexes were studied by TG-DSC/FTIR. The solid state photoluminescent properties of complex 3 were investigated at room temperature. Moreover, the antibacterial activities of complexes 1–4 on Candida albicans were studied.