Tb Compound Research Articles

A Tb and Ag co-doped borate compound forms a high sensitive X-ray, gamma-ray and neutron luminescence dosimeter

Thermal and optical stimulations of neutron-sensitive CaB6O10:Tb3+,Ag+ led to two recombination pathways.

Blue-Emitting Ligand-Mediated Assembly of Rare-Earth MOFs toward White-Light Emission, Sensing, Magnetic, and Catalytic Studies.

New lanthanide carboxylate compounds with two- (2D) and three-dimensional (3D) structures have been prepared by employing 2,5-bis(prop-2-yn-1-yloxy)terephthalic acid (2,5-BPTA) as an organic linker. The compounds, [Ln(C14H8O6)(C7O3H4)·2H2O]·4(H2O), Ln = Y, Pr, Nd, Sm, Eu, Gd, Tb, Dy and [Ln(C7O3H4)3·(C3H7ON)·(H2O)]·2(H2O)(C3H7NO), Ln = La, Ce, Pr, have two- and three-dimensional structures, respectively. In all compounds, lanthanide ions are connected together, forming a dimer, which is connected by the 2,5-BPTA ligand. In the two-dimensional structure, there are two 2,5-BPTA moieties present, and in the three-dimensional structure, there are three 2,5-BPTA moieties present. The lanthanide centers are nine-coordinated, the 2D structure has a tricapped trigonal prismatic arrangement, and the 3D structure has a monocapped distorted square antiprismatic arrangement. The Pr compound forms in both 2D and 3D structures, whose formation depends on the time of the reaction (2 days─2D and 5-6 days─3D). The ligand emits in the blue region, and using the characteristic emission of Eu3+ (red) and Tb3+ (green) ions, we achieve white light emission in the (Y0.96Tb0.02Eu0.02) compound. The overall quantum yield for the white light emission is 28%. The strong green luminescence of the Tb3+-containing compound was employed to selectively sense the Cr3+ and Fe3+ ions in aqueous solution with limits of detection (LODs) at 0.41 and 8.6 ppm, respectively. The Tb compound was found to be a good heterogeneous catalyst for the Ullman-type O-arylation reaction between phenol and bromoarene with yields of 95%. Magnetic studies on the Gd-, Tb-, and Dy-containing compounds showed weak exchange interactions within the dimeric Ln2 units. The present work demonstrates the many utilities of the rare-earth-containing MOFs, especially toward white-light emission, metal-ion sensing, and heterogeneous catalysis.

Magnetic structures of nearly isostructural Tb3RuO7 and Nd3RuO7 : Appearance of a partially disordered state only in the Tb compound

We report on the magnetic structures of ${\mathrm{Tb}}_{3}{\mathrm{RuO}}_{7}$ and ${\mathrm{Nd}}_{3}{\mathrm{RuO}}_{7}$ determined from powder neutron-diffraction experiments. In ${\mathrm{Tb}}_{3}{\mathrm{RuO}}_{7}$, alternating-bond spin-$\frac{3}{2}$ Ru1-Ru2 chains are formed. The Ru1 and Ru2 moments are ordered and disordered (paramagnetic), respectively, below 15 K. This result indicates the appearance of a partially disordered (PD) state, although the two Ru sites are very similar to each other. In ${\mathrm{Nd}}_{3}{\mathrm{RuO}}_{7}$, the Ru1 and Ru2 ions form independent uniform chains. Both the Ru1 and Ru2 moments are ordered below 17.5 K. Probably, the main source of the PD state in ${\mathrm{Tb}}_{3}{\mathrm{RuO}}_{7}$ is the magnetic frustration in the exchange interactions. The internal magnetic field generated by the Tb ordered moments at the Ru1 sites is different from that at the Ru2 sites. We speculate that the different (nonuniform) internal magnetic field enhances the difference in the properties between the Ru1 and Ru2 moments. We also report on the magnetic entropy changes of ${\mathrm{Tb}}_{3}{\mathrm{RuO}}_{7}$ and ${\mathrm{Gd}}_{3}{\mathrm{RuO}}_{7}$.

Luminescence behavior of PMMA films doped with Tb(III) and Eu(III) complexes

Novel hybrid systems based on the poly(methyl methacrylate) (PMMA) matrix and Eu(III) and Tb(III) tris(β-diketonates) complexes with 1,10-phenanthroline were synthesized and analyzed as light-conversion materials. Solutions of the Tb(III) and Eu(III) complexes doped into PMMA were spin-coated to fabricate films with various concentrations of luminophores. Long hydrocarbon substituents in the structure of complexes inhibit their crystallization. In turn, it allows to vary the luminophore content in a polymer matrix in a broader range and achieve the maximum of emission with higher concentrations of dopants. The addition of the Tb(III) complex to the system results in a 26% increase in the relative luminescence quantum yield of the Eu(III) ions due to an additional energy transfer from the Tb(III) compound. The results of this work illustrate that although the Eu(III) and Tb(III) complexes exhibit lower rate and efficiency of energy transfer than their well-known Tb(acac)3 and Eu(tta)3 analogues, the structural features of lanthanide complexes allow to efficiently dope a PMMA matrix with considerably larger amounts of luminophores. It offers broader application opportunities for the coordination Ln(III) compounds as polyfunctional materials for optics and optoelectronics.

LnIII-NiII heterometallic compounds linked by nitronyl nitroxides: Structure and magnetism

Two Ln-Ni heterometallic complexes connected with nitronyl nitroxides [Ln(hfac)3Ni(hfac)2NIT-4py(H2O)2] (Ln = Gd (1), Tb (2); hfac = hexafluoroacetylacetonate; NIT-4py = 2-(4-pyridyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) have been synthesized as well as characterized. For two complexes, the NIT-4py radical is ligated to the Ln(III) ion and Ni(II) ion via its NO moiety and pyridine-N atom, respectively, resulting in rare radical bridged Ln-Ni heterobinuclear structure. Magnetic studies reveal that the magnetic exchanges arising from the uncoordinated NO groups dominate the system. Interestingly, the Tb compound displays a slow relaxation of magnetization.

Competing magnetic interactions and magnetoresistance anomalies in cubic intermetallic compounds, Gd4RhAl and Tb4RhAl , and enhanced magnetocaloric effect for the Tb case

We report complex magnetic, magnetoresistance (MR), and magnetocaloric properties of ${\mathrm{Gd}}_{4}\mathrm{RhAl}$ and ${\mathrm{Tb}}_{4}\mathrm{RhAl}$, forming in the ${\mathrm{Gd}}_{4}\mathrm{RhIn}$-type cubic structure. Though the synthesis of the compounds was reported long ago, to our knowledge, no attempt was made to investigate the properties of these compounds. The present results of ac and dc magnetization, electrical resistivity, and heat-capacity measurements down to 1.8 K establish that these compounds undergo antiferromagnetic order initially, followed by complex spin-glass features with decreasing temperature. These characteristic temperatures are as follows: for the Gd case, ${T}_{N}=\ensuremath{\sim}46\phantom{\rule{0.16em}{0ex}}\mathrm{K}$ and ${T}_{G}=\ensuremath{\sim}21\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, and for Tb, \ensuremath{\sim}32 and \ensuremath{\sim}28 K, respectively. Additionally, there are field-induced magnetic effects, interestingly leading to nonmonotonic variations in MR. There is a significant MR over a wide temperature range above ${T}_{N}$, similar to the behavior of the magnetocaloric effect (MCE) as measured by isothermal entropy change (\ensuremath{\Delta}S). An intriguing finding we made is that \ensuremath{\Delta}S at the onset of magnetic order is significantly larger for the Tb compound than that observed for the Gd analog near its ${T}_{N}$. On the basis of this observation in a cubic material, we raise the question of whether the aspherical nature of the $4f$ orbital can play a role to enhance MCE under favorable circumstances---a clue that could be useful to find materials for magnetocaloric applications.

High-Content Screening of Eukaryotic Kinase Inhibitors Identify CHK2 Inhibitor Activity Against Mycobacterium tuberculosis.

A screen of a eukaryotic kinase inhibitor library in an established intracellular infection model identified a set of drug candidates enabling intracellular killing of Mycobacterium tuberculosis (M.tb). Screen validity was confirmed internally by a Z′ = 0.5 and externally by detecting previously reported host-targeting anti-M.tb compounds. Inhibitors of the CHK kinase family, specifically checkpoint kinase 2 (CHK2), showed the highest inhibition and lowest toxicity of all kinase families. The screen identified and validated DDUG, a CHK2 inhibitor, as a novel bactericidal anti-M.tb compound. CHK2 inhibition by RNAi phenocopied the intracellular inhibitory effect of DDUG. DDUG was active intracellularly against M.tb, but not other mycobacteria. DDUG also had extracellular activity against 4 of 12 bacteria tested, including M.tb. Combined, these observations suggest DDUG acts in tandem against both host and pathogen. Importantly, DDUG’s validation highlights the screening and analysis methodology developed for this screen, which identified novel host-directed anti-M.tb compounds.

Spin-glass features at multiple temperatures and transport anomalies in Tb4PtAl

The magnetic and electrical transport properties of Tb4PtAl, crystallizing in the Gd4RhIn-type cubic crystal structure characterized by three sites for the rare-earth, are reported by the measurements of magnetization, heat-capacity, and electrical resistivity (1.8–300 K). In comparison with the Gd analog, which has been shown to exhibit a complex magnetism with antiferromagnetism (TN = 64 K) entering into a spin-glass phase below 20 K, the spin-glass phase coexists at the onset of the antiferromagnetic order at 50 K in the Tb compound; additional spin-glass anomalies around 8 and 25 K are also found. Interestingly, the plot of electrical resistivity vs temperature develops a minimum in the presence of an external magnetic field above 50 K, and this transport behavior, unusual among rare-earth intermetallics, is presumably due to the gradual growth of short-range antiferromagnetic clusters as the long-range magnetic order develops.

Cs3REIIIGe3O9 (RE = Pr, Nd, and Sm-Yb) and Cs8TbIII2TbIVGe9O27: A Rare Example of a Mixed-Valent Tb(III)/Tb(IV) Oxide.

Single crystals of 12 new cesium rare earth germanates crystallizing in two new structure types were grown from a CsCl/CsF flux. Cs3REGe3O9 (RE = Pr, Nd, and Sm-Yb), a new family of germanates that form for almost the entire series of rare earth elements, crystallizes in orthorhombic space group Pna21 with lattice parameters in the following ranges: a = 13.7033(4)-14.022(2) Å, b = 7.0545(2)-7.2405(12) Å, and c = 12.6672(4)-12.836(2) Å. Surprisingly, the Tb reaction yielded both Cs3TbGe3O9 and Cs8Tb3Ge9O27, a rare example of a mixed-valent Tb(III)/Tb(IV) compound. Cs8Tb3Ge9O27 crystallizes in space group P3 with the following lattice parameters: a = 11.2906(4) Å, and c = 7.9605(3) Å. The mixed-valent oxidation state of Tb was confirmed by structure solution, bond-valence sums, X-ray photoelectron spectroscopy data, and magnetic data. Optical and magnetic properties are reported for both sets of compounds.

Multiphase Characterization of Phase Equilibria in the Tb-Rich Corner of the Co-Cu-Tb System

In recent years, the grain-boundary diffusion (GBD) and grain-boundary restructuring processes used in manufacturing Nd-Fe-B magnets show promise as procedures that allow one to increase their hysteretic characteristics. The processes are realized by adding various amounts of heavy-rare-earth metals (in the form of hydrides, oxides, intermetallic compounds, etc.) to powder mixtures. The additions decompose or melt during subsequent heat treatment, and their components diffuse into grains and remain within the grain-boundary phase and thus, increase the anisotropy field of the main-magnetic (Nd2Fe14B-based) phase and improve the grain-boundary structure, respectively. In the present study, we consider alloys near the Tb3(Co0.6Cu0.4) composition as such an addition, which is of importance in designing the microstructure of Nd-Fe-B permanent magnets allowing us to economically alloy them with terbium (via GBD) simultaneously making copper and cobalt parts of the magnet composition. The phase equilibria in the Tb-rich corner of the Co-Cu-Tb system near the Tb3(Co0.6Cu0.4) composition, which was found to be multiphase, are assessed based on electron microscopy studies, data from electron microprobe, x-ray diffraction, and differential thermal analyses, and from magnetic measurements. A portion of the isothermal section for compositions Tb-40 at.% Co-50 at.% Cu at 600°C was constructed. The copper solubility in Tb3(Co,Cu) and Tb12(Co,Cu)7, and Co solubility in the Tb(Cu,Co) compound were determined, which are up to 6.5, 14.5, and 10 at.%, respectively. The possibility of hydrogenation of the multiphase composition with the formation of TbHx, and fine Co and Cu powders, which are components for diffusion in manufacturing permanent magnets, is demonstrated.

New Compounds of Some Trivalent Lanthanides and Actinides with Furancarboxylic Acid. Synthesis, Structure, and Absorption Spectra of the Complexes [(NH2)3C]2[M(OOCC4H3O)5] (M = La, Ce, Pr, Nd, Tb, Np, Pu, Am)

Eight new compounds of some lanthanides and actinides with furancarboxylate anion were synthesized and studied. Their structure was determined by single crystal X-ray diffraction. All the compounds contain complex anions [M(OOCC4H3O)5]2– in which four of five furancarboxylate anions coordinate the central metal atom in the bidentate fashion via carboxy groups, whereas the fifth anion is bonded to the metal atom only via one O atom of the carboxy group. In all the complexes except the Tb compound the ether oxygen atom of the fifth furancarboxylate anion is also bonded to the metal atom; i.e., a five-membered chelate ring (МОССО) is formed. Such bond is not formed in the Tb compound. Thus, the coordination number of the central atom is 9 in the Tb compound and 10 in the other complexes.

Picomolar Traces of Americium(III) Introduce Drastic Changes in the Structural Chemistry of Terbium(III): A Break in the "Gadolinium Break".

The crystallization of terbium 5,5'-azobis[1H-tetrazol-1-ide] (ZT) in the presence of trace amounts (ca. 50 Bq, ca. 1.6 pmol) of americium results in 1) the accumulation of the americium tracer in the crystalline solid and 2) a material that adopts a different crystal structure to that formed in the absence of americium. Americium-doped [Tb(Am)(H2 O)7 ZT]2 ZT⋅10 H2 O is isostructural to light lanthanide (Ce-Gd) 5,5'-azobis[1H-tetrazol-1-ide] compounds, rather than to the heavy lanthanide (Tb-Lu) 5,5'-azobis[1H-tetrazol-1-ide] (e.g., [Tb(H2 O)8 ]2 ZT3 ⋅6 H2 O) derivatives. Traces of Am seem to force the Tb compound into a structure normally preferred by the lighter lanthanides, despite a 108 -fold Tb excess. The americium-doped material was studied by single-crystal X-ray diffraction, vibrational spectroscopy, radiochemical neutron activation analysis, and scanning electron microcopy. In addition, the inclusion properties of terbium 5,5'-azobis[1H-tetrazol-1-ide] towards americium were quantified, and a model for the crystallization process is proposed.

Magnetic behavior of metallic kagome lattices, Tb3Ru4Al12 and Er3Ru4Al12

We report the magnetic behavior of two intermetallic-based kagome lattices, Tb3Ru4Al12 and Er3Ru4Al12, crystallizing in the Gd3Ru4Al2-type hexagonal crystal structure, by measurements in the range 1.8–300 K with bulk experimental techniques (ac and dc magnetization, heat capacity, and magnetoresistance). The main finding is that the Tb compound, known to order antiferromagnetically below (TN=) 22 K, shows glassy characteristics at lower temperatures (15 K), thus characterizing this compound as a re-entrant spin-glass. The data reveal that the glassy phase is quite complex and is of a cluster type. Since glassy behavior was not seen for the Gd analog in the past literature, this finding on the Tb compound emphasizes that this kagome family could provide an opportunity to explore the role of higher-order interactions (such as quadrupole) in bringing out magnetic frustration. Additional findings reported here for this compound are: (i) The plots of temperature dependence of magnetic susceptibility and electrical resistivity data in the range 12–20 K, just below TN, are found to be hysteretic leading to a magnetic phase in this intermediate temperature range, mimicking disorder-broadened first-order magnetic phase transitions; (ii) features attributable to an interesting magnetic phase co-existence phenomenon in the isothermal magnetoresistance in zero field, after travelling across metamagnetic transition fields, are observed. With respect to the Er compound, we do not find any evidence for long-range magnetic ordering down to 2 K, but this compound appears to be on the verge of magnetic order at 2 K.

Preparation and luminescent properties of (Tb3+-Yb3+)SSA/(SBA-15) composite materials

In this study, the sulfosalicylic acid (SSA)-Tb and Yb compound were systematically assembled into the pores of SBA-15 by hydrothermal method. The luminescence properties of the prepared materials were studied through luminescence spectra. The influences of the content of Yb3+ and Tb3+ on luminescent properties have been studied, and the luminescence mechanisms were analyzed. By the emission spectrum intensity, the optimum proportion of Tb and Yb was confirmed. In prepared materials, the ordered mesoporous structures were retained, and the prepared materials showed the much stronger emission of Tb3+ at 543nm. The luminescence intensity attained the maximum when Yb3+ molar content was 4%, and the Tb3+ molar content was 2%. The prepared materials have potential applications value in luminescent materials field.

Synthesis and structure determination of seven ternary bismuthides: crystal chemistry of the RELi3Bi2 family (RE = La-Nd, Sm, Gd, and Tb).

Zintl phases are renowned for their diverse crystal structures with rich structural chemistry and have recently exhibited some remarkable heat- and charge-transport properties. The ternary bismuthides RELi3Bi2 (RE = La-Nd, Sm, Gd, and Tb) (namely, lanthanum trilithium dibismuthide, LaLi3Bi2, cerium trilithium dibismuthide, CeLi3Bi2, praseodymium trilithium dibismuthide, PrLi3Bi2, neodymium trilithium dibismuthide, NdLi3Bi2, samarium trilithium dibismuthide, SmLi3Bi2, gadolinium trilithium dibismuthide, GdLi3Bi2, and terbium trilithium dibismuthide, TbLi3Bi2) were synthesized by high-temperature reactions of the elements in sealed Nb ampoules. Single-crystal X-ray diffraction analysis shows that all seven compounds are isostructural and crystallize in the LaLi3Sb2 type structure in the trigonal space group P-3m1 (Pearson symbol hP6). The unit-cell volumes decrease monotonically on moving from the La to the Tb compound, owing to the lanthanide contraction. The structure features a rare-earth metal atom and one Li atom in a nearly perfect octahedral coordination by six Bi atoms. The second crystallographically unique Li atom is surrounded by four Bi atoms in a slightly distorted tetrahedral geometry. The atomic arrangements are best described as layered structures consisting of two-dimensional layers of fused LiBi4 tetrahedra and LiBi6 octahedra, separated by rare-earth metal cations. As such, these compounds are expected to be valance-precise semiconductors, whose formulae can be represented as (RE(3+))(Li(1+))3(Bi(3-))2.

Dy, Tb, Gd and Eu complexes with low melting point and magnetic behavior

Three new complexes based on lanthanide(III) tetrakis(β-diketonate) with a tetraalkylphosphonium as counterion [P6,6,6,14][Ln(NTA)4] (Ln=Dy (1), Tb (2), Gd (3); NTA=naphthoyltrifluoroacetone; P6,6,6,14=trihexyl(tetradecyl)phosphonium) were synthesized. The complexes were fully characterized and their spectroscopic, thermal and magnetic properties were evaluated, together with the Eu (4) analogue. The Dy (1) compound showed solvatochromic properties, the Tb (2) compound presented an unprecedented solid state polymorphism never observed in an organometallic compound and all complexes presented paramagnetic behavior with no interactions between the magnetic moments.

Old TB Compound Performs As Prodrug

RETURN TO ISSUEPREVNewsNEXTOld TB Compound Performs As ProdrugCite this: Chem. Eng. News 2012, 90, 45, 9Publication Date (Print):November 4, 2012Publication History Published online29 March 2013Published inissue 4 November 2012https://doi.org/10.1021/cen-09045-notw4Copyright © 2012 Chemical & Engineering NewsArticle Views10Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit PDF (149 KB) SUBJECTS:Infectious diseases Get e-Alerts

Amine-Templated Polymeric Lanthanide Formates: Synthesis, Characterization, and Applications in Luminescence and Magnetism

The novel polymeric formates of general formula [(Fmd)Ln(III)(HCOO)(4)](∞) (Fmd(+) = NH(2)-CH(+)-NH(2); Ln = Eu (1), Gd (2), Tb (3), Dy (4)] were synthesized through solvothermal methods in formamide solutions. The compounds are isotructural; they crystallize in the orthorhombic C222(1) chiral space group. The coordination geometry at the metal centers is square antiprismatic (coordination number eight), with each formate ligand bridging adjacent lanthanide ions. The overall negative three-dimensional (3D) framework charge is balanced by the formamidinium cations sitting inside the channels along the a axis, forming extensive N-H···O hydrogen bonding with the surrounding cage. All the compounds have been characterized through single-crystal/powder X-ray diffraction, IR spectroscopy, and TG-MS analysis. Finally, their luminescence and magnetic properties have been assessed, leading to remarkable emission intensities, especially for the Tb(III) compound (Φ = 0.83), with corresponding lifetime decays in the micro (Dy) and millisecond (Tb, Eu) time scale. A weak but sizable antiferromagnetic interaction has been observed for the Gd(III) derivative.

Syntheses, structures, and properties of lanthanide–organic frameworks with flexible disulfide derivative of carboxylate

Reaction of disulfide-containing ligand 6,6′-dithiodinicotinic acid (H 2cpds) with lanthanide metal salts led to three compounds {[Ln 2(cpds) 3(H 2O) 5]·7H 2O} n (Ln = Gd, 1; Tb, 2; Er, 3) under hydrothermal conditions. The single-crystal X-ray diffraction analysis revealed that complexes 1– 3 are isostructural. Two eight-coordinated metal centers are connected with carboxylate groups of H 2cpds to give a binuclear [Ln 2(CO 2) 4] unit. H 2cpds discloses two independent binding modes resulting in the two types of 1-D chains by the connection of [Ln 2(CO 2) 4] unit. Finally, the 1-D chains are linked by H 2cpds to construct a 3-D network with an uncommon twofold interpenetrating 4-connected CdSO 4 structure type (6 5,8 topology). It is worth noting that polyrotaxane-like motif is also exhibited in the 3-D network. The Tb(III) compound exhibits strong green photoluminescence in the visible region. Furthermore, the magnetic property of the Gd(III) compound has been investigated in the temperature range of 2–300 K. The thermal behaviors and XPRD patterns of three compounds have also been discussed.

Ln2GeB2O8 (Ln = Nd, Sm–Tb): a series of luminescent lanthanide(iii) borogermanates with a layered structure

A series of new lanthanide borogermanates, namely, Ln(2)GeB(2)O(8) (Ln = Nd, Sm-Tb), have been synthesized by high temperature solid state reactions in platinum crucibles. They are isostructural and feature a layered [GeB(2)O(8)](6-) architecture built of 1D chains of corner-sharing BO(4)-tetrahedra that are further bridged by GeO(4)-tetrahedra. The lanthanide(III) ions are located at the interlayer space and are seven-coordinated. Results of magnetic measurements indicate Sm(III), Eu(III) and Gd(III) compounds display an antiferromagnetic interaction between Ln(III) centers whereas the Tb(III) compound exhibits a ferromagnetic interaction between Tb(3+) ions. Luminescent studies indicate that Eu(2)GeB(2)O(8) and Tb(2)GeB(2)O(8) emit strong red and green light, respectively.