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Sample records for lanthanide btp complexes

  1. Luminescent macrocyclic lanthanide complexes

    DOEpatents

    Raymond, Kenneth N.; Corneillie, Todd M.; Xu, Jide

    2012-05-08

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  2. Luminescent macrocyclic lanthanide complexes

    DOEpatents

    Raymond, Kenneth N; Corneillie, Todd M; Xu, Jide

    2014-05-20

    The present invention provides a novel class of macrocyclic compounds as well as complexes formed between a metal (e.g., lanthanide) ion and the compounds of the invention. Preferred complexes exhibit high stability as well as high quantum yields of lanthanide ion luminescence in aqueous media without the need for secondary activating agents. Preferred compounds incorporate hydroxy-isophthalamide moieties within their macrocyclic structure and are characterized by surprisingly low, non-specific binding to a variety of polypeptides such as antibodies and proteins as well as high kinetic stability. These characteristics distinguish them from known, open-structured ligands.

  3. Self-assembly formation of a healable lanthanide luminescent supramolecular metallogel from 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligands.

    PubMed

    McCarney, Eoin P; Byrne, Joseph P; Twamley, Brendan; Martínez-Calvo, Miguel; Ryan, Gavin; Möbius, Matthias E; Gunnlaugsson, Thorfinnur

    2015-09-25

    The synthesis of five new 2,6-bis(1,2,3-triazol-4-yl)pyridine (btp) ligands is described: the self-assembly behaviour of the tri-methyl ester, 1, with Eu(III) showed the formation of a luminescent 1:3 Eu : btp complex, Eu13, which was studied in solution and in the solid state; while the tri-carboxylic acid, 2, formed a hydrogel and its corresponding complex Eu23, gave rise to a strongly red luminescent healable metallogel. PMID:26258184

  4. Aromatic triamide-lanthanide complexes

    DOEpatents

    Raymond, Kenneth N; Petoud, Stephane; Xu, Jide

    2013-10-08

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  5. Enantioselective catalysis using lanthanide Schiff base complexes

    SciTech Connect

    Watkin, J.G.

    1996-10-01

    The use of lanthanide-based catalysts to facilitate organic transformations is currently an area of rapid growth, in particular the application of lanthanide alkoxide and triflate derivatives as effective Lewis-acidic catalysts for Michael additions and aldol reactions, and bis-pentamethylcyclopentadienyl derivatives as extremely active catalysts for hydrogenation and enantioselective hydroamination reactions. We have begun an investigation into the use of lanthanide complexes containing chiral alkoxide ligands as Lewis-acidic catalysts for enantioselective organic reactions. Since the large ionic radii of the lanthanide +III metal centers can often lead to oligomerization of simple alkoxide species, we have also examined the use of multidentate, chelating Schiff base ligands to provide an asymmetric environment about a lanthanide metal center. Structural investigations of the catalysts will be described, together with the use of these catalysts in enantioselective Meerwein-Ponndorf-Verley reduction of ketones and nitroaldol reactions.

  6. Chiroptical Probing of Lanthanide-Directed Self-Assembly Formation Using btp Ligands Formed in One-Pot Diazo-Transfer/Deprotection Click Reaction from Chiral Amines.

    PubMed

    Byrne, Joseph P; Martínez-Calvo, Miguel; Peacock, Robert D; Gunnlaugsson, Thorfinnur

    2016-01-11

    A series of enantiomeric 2,6-bis(1,2,3-triazol-4-yl)pyridines (btp)-containing ligands was synthesized by a one-pot two-step copper-catalyzed amine/alkyne click reaction. The Eu(III) - and Tb(III) -directed self-assembly formation of these ligands was studied in CH3 CN by monitoring their various photophysical properties, including their emerging circular dichroism and circularly polarized luminescence. The global analysis of the former enabled the determination of both the stoichiometry and the stability constants of the various chiral supramolecular species in solution. PMID:26555573

  7. Complexes of Lapachol and Lawsone with Lanthanides.

    PubMed

    Genovese, Salvatore; Taddeo, Vito Alessandro; Epifano, Francesco; Fiorito, Serena

    2015-11-01

    Naturally occurring 2-hydroxy-1,4-naphthoquinones are well known to form readily stable complexes with transition metals. In this short communication we describe for the first time the synthesis and preliminary data about structural characterization of complexes between two naturally widespread 2-hydroxy-1,4-naphthoquinones, namely lapachol (1) and lawsone (2), with selected lanthanides like lanthanum, gadolinium, and ytterbium. When tested as cytotoxic compounds, such complexes exhibited an activity that was either higher or equal to that of the parent naphthoquinone. PMID:26749803

  8. Calibration beads containing luminescent lanthanide ion complexes

    EPA Science Inventory

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...

  9. De Novo Designed Imaging Agents Based on Lanthanide Peptides Complexes.

    PubMed

    Peacock, A F A

    2016-01-01

    Herein are discussed a selection of lanthanide peptide/protein complexes in view of their potential applications as imaging agents, both in terms of luminescence detection and magnetic resonance imaging. Though this chapter covers a range of different peptides and protein, if focuses specifically on the opportunities afforded by the de novo design of coiled coils, miniature protein scaffolds, and the development on lanthanide-binding sites into these architectures. The requirements for lanthanide coordination and the challenges that need to be addressed when preparing lanthanide peptides with a view to their potential adoption as clinical imaging applications, will be highlighted. PMID:27586349

  10. Salicylamide-lanthanide complexes for use as luminescent markers

    SciTech Connect

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2008-07-29

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  11. Salicylamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2002-01-01

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  12. Phthalamide lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth M.; Xu, Jide

    2003-01-01

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  13. Salicylamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2006-03-28

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one salicylamidyl moiety. Also provided are probes incorporating the salicylamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  14. Phthalamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth M.; Xu, Jide

    2005-03-08

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  15. Phthalamide-lanthanide complexes for use as luminescent markers

    DOEpatents

    Raymond, Kenneth N.; Petoud, Stephane; Cohen, Seth; Xu, Jide

    2008-10-28

    The present invention provides luminescent lanthanide metal chelates comprising a metal ion of the lanthanide series and a complexing agent comprising at least one phthalamidyl moiety. Also provided are probes incorporating the phthalamidyl ligands of the invention and methods utilizing the ligands of the invention and probes comprising the ligands of the invention.

  16. Calibration beads containing luminescent lanthanide ion complexes

    NASA Astrophysics Data System (ADS)

    Leif, Robert C.; Jin, Dayong; Piper, James; Vallarino, Lidia M.; Williams, John W.; Yang, Sean; Zucker, Robert M.

    2008-02-01

    The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including microscopes. Methods: 0.5, 3, and 5 micron (µm) beads containing a luminescent europium-complex were manufactured and the luminescence distribution of the 5 µm beads was measured with a time-delayed luminescence flow cytometer and a timedelayed digital microscope. The distribution of the luminescence intensity from the europium-complex in individual beads was determined on optical sections by confocal microscopy. The emission spectra of the beads under UV excitation were determined with a PARISS® spectrophotometer. The kinetics of the luminescence bleaching caused by UV irradiation were measured under LED excitation with a fluorescence microscope. Results: The kinetics of UV bleaching were very similar for the 0.5, 3, and 5 µm beads. Emission peaks were found at 592, 616, and 685 nanometers (nm). The width of the principal peak at half-maximum (616 nm) was 9.9 nm. The luminescence lifetimes in water and in air were 340 and 460 microseconds (µs), respectively. The distribution of the europium- complex in the beads was homogeneous. Conclusions: The 5 µm beads can be used for spectral calibration of microscopes equipped with a spectrograph, as test particles for time-delayed luminescence flow cytometers, and possibly as labels for macromolecules and cells.

  17. Lanthanide Complexes as a Test for Evidence of Life

    NASA Technical Reports Server (NTRS)

    Benavides, Jeannette

    1998-01-01

    The objective of this research is to advance the understanding of the interaction of lanthanide metals with biological organic molecules and to develop a technique to detect these compounds in the solid state and in situ in Mars and other planetary bodies. The detection of these complexes should provide evidence of life past or present. In addition, detection of the metals alone will provide important information about the geological history of a planetary body. Lanthanides were chosen as our focus of interest because they form very stable complexes with organic molecules in solution and they produce intense luminescence in the ultraviolet and visible spectra. The rare earth complexes available are mostly synthetic for diverse applications in medicine. There is not much work done on the complexes that form in nature. Lanthanides have many applications and they are mined aR over the world, however, since the interest has been only in the elements, the analytical techniques employed destroy any organic ligands that may be present. In order to determine if and which lanthanide complexes form in nature and their concentration, soil samples have been collected from areas rich in soluble lanthanide compounds like phosphates and also rich in vegetation. The soil samples will be analyzed and the lanthanide complexes if present will be isolated and characterized. A spectrometer to detect the lanthanide complexes in situ and in the solid state will be designed. In this workshop, the research approach and its implications will be discussed.

  18. Luminescent chiral lanthanide(III) complexes as potential molecular probes

    PubMed Central

    Muller, Gilles

    2009-01-01

    This perspective gives an introduction into the design of luminescent lanthanide(III)-containing complexes possessing chiral properties and used to probe biological materials. The first part briefly describes general principles, focusing on the optical aspect (i.e. lanthanide luminescence, sensitization processes) of the most emissive trivalent lanthanide ions, europium and terbium, incorporated into molecular luminescent edifices. This is followed by a short discussion on the importance of chirality in the biological and pharmaceutical fields. The second part is devoted to the assessment of the chiroptical spectroscopic tools available (typically circular dichroism and circularly polarized luminescence) and the strategies used to introduce a chiral feature into luminescent lanthanide(III) complexes (chiral structure resulting from a chiral arrangement of the ligand molecules surrounding the luminescent center or presence of chiral centers in the ligand molecules). Finally, the last part illustrates these fundamental principles with recent selected examples of such chiral luminescent lanthanide-based compounds used as potential probes of biomolecular substrates. PMID:19885510

  19. Experimental and Theoretical Studies on Biologically Active Lanthanide (III) Complexes

    NASA Astrophysics Data System (ADS)

    Kostova, I.; Trendafilova, N.; Georgieva, I.; Rastogi, V. K.; Kiefer, W.

    2008-11-01

    The complexation ability and the binding mode of the ligand coumarin-3-carboxylic acid (HCCA) to La(III), Ce(III), Nd(III), Sm(III), Gd(III) and Dy(III) lanthanide ions (Ln(III)) are elucidated at experimental and theoretical level. The complexes were characterized using elemental analysis, DTA and TGA data as well as 1H NMR and 13C NMR spectra. FTIR and Raman spectroscopic techniques as well as DFT quantum chemical calculations were used for characterization of the binding mode and the structures of lanthanide(III) complexes of HCCA. The metal—ligand binding mode is predicted through molecular modeling and energy estimation of different Ln—CCA structures using B3LYP/6-31G(d) method combined with a large quasi-relativistic effective core potential for lanthanide ion. The energies obtained predict bidentate coordination of CCA- to Ln(III) ions through the carbonylic oxygen and the carboxylic oxygen. Detailed vibrational analysis of HCCA, CCA- and Ln(III) complexes based on both calculated and experimental frequencies confirms the suggested metal—ligand binding mode. The natural bonding analysis predicts strongly ionic character of the Ln(III)-CCA bonding in the- complexes studied. With the relatively resistant tumor cell line K-562 we obtained very interesting in-vitro results which are in accordance with our previously published data concerning the activity of lanthanide(III) complexes with other coumarin derivatives.

  20. Detection of Bacterial Spores with Lanthanide-Macrocycle Binary Complexes

    PubMed Central

    Cable, Morgan L.; Kirby, James P.; Levine, Dana J.; Manary, Micah J.; Gray, Harry B.; Ponce, Adrian

    2009-01-01

    The detection of bacterial spores via dipicolinate-triggered lanthanide luminescence has been improved in terms of detection limit, stability, and susceptibility to interferents by use of lanthanide-macrocycle binary complexes. Specifically, we compared the effectiveness of Sm, Eu, Tb and Dy complexes with the macrocycle 1,4,7,10-tetraazacyclododecane-1,7-diacetate (DO2A) to the corresponding lanthanide aquo ions. The Ln(DO2A)+ binary complexes bind dipicolinic acid (DPA), a major constituent of bacterial spores, with greater affinity and demonstrate significant improvement in bacterial spore detection. Of the four luminescent lanthanides studied, the terbium complex exhibits the greatest dipicolinate binding affinity (100-fold greater than Tb3+ alone, and 10-fold greater than other Ln(DO2A)+ complexes) and highest quantum yield. Moreover, the inclusion of DO2A extends the pH range over which Tb-DPA coordination is stable, reduces the interference of calcium ions nearly 5-fold, and mitigates phosphate interference 1000-fold compared to free terbium alone. In addition, detection of Bacillus atrophaeus bacterial spores was improved by the use of Tb(DO2A)+, yielding a 3-fold increase in the signal-to-noise ratio over Tb3+. Out of the eight cases investigated, the Tb(DO2A)+ binary complex is best for the detection of bacterial spores. PMID:19537757

  1. Applications of DFT to Lanthanides and Precious Metal Complexes

    NASA Astrophysics Data System (ADS)

    Balboa, Alex; Hurley, Margaret; Jenkins, Amanda; None Collaboration; None Collaboration

    2014-03-01

    Density functional theory is widely used for computational characterization of novel materials. While study of materials containing the lighter elements is commonplace, the application of these methods to the bottom of the periodic table, including the lanthanides and the heavier precious metals such as Osmium, requires careful validation. Here we present results of recent quantum mechanical studies to characterize Lanthanide/Graphene Materials and assess the suitability of DFT for these systems. Additionally, we will present recent work on similar application of DFT to characterize Os bipridine complexes.

  2. Lanthanide complexes of azidophenacyl-DO3A as new synthons for click chemistry and the synthesis of heterometallic lanthanide arrays.

    PubMed

    Tropiano, Manuel; Kenwright, Alan M; Faulkner, Stephen

    2015-04-01

    Lanthanide complexes of azidophenacyl DO3A are effective substrates for click reactions with ethyne derivatives, giving rise to aryl triazole appended lanthanide complexes, in which the aryl triazole acts as an effective sensitising chromophore for lanthanide luminescence. They also undergo click chemistry with propargylDO3A derivatives, giving rise to heterometallic complexes.

  3. Energetic lanthanide complexes: coordination chemistry and explosives applications

    NASA Astrophysics Data System (ADS)

    Manner, V. W.; Barker, B. J.; Sanders, V. E.; Laintz, K. E.; Scott, B. L.; Preston, D. N.; Sandstrom, M.; Reardon, B. L.

    2014-05-01

    Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with 'tailor made' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

  4. Energetic Lanthanide Complexes: Coordination Chemistry and Explosives Applications

    NASA Astrophysics Data System (ADS)

    Manner, Virginia; Barker, Beau; Sanders, Eric; Laintz, Kenneth; Scott, Brian; Preston, Daniel; Sandstrom, Mary; Reardon, Bettina

    2013-06-01

    Metals are generally added to organic molecular explosives in a heterogeneous composite to improve overall heat and energy release. In order to avoid creating a mixture that can vary in homogeneity, energetic organic molecules can be directly bonded to high molecular weight metals, forming a single metal complex with Angstrom-scale separation between the metal and the explosive. To probe the relationship between the structural properties of metal complexes and explosive performance, a new series of energetic lanthanide complexes has been prepared using energetic ligands such as NTO (5-nitro-2,4-dihydro-1,2,4-triazole-3-one). These are the first examples of lanthanide NTO complexes where no water is coordinated to the metal, demonstrating novel control of the coordination environment. The complexes have been characterized by X-ray crystallography, NMR and IR spectroscopies, photoluminescence, and sensitivity testing. The structural and energetic properties are discussed in the context of enhanced blast effects and detection. Cheetah calculations have been performed to fine-tune physical properties, creating a systematic method for producing explosives with ``tailor made'' characteristics. These new complexes will be benchmarks for further study in the field of metalized high explosives.

  5. Magnetic Interactions in a Series of Homodinuclear Lanthanide Complexes.

    PubMed

    Comba, Peter; Großhauser, Michael; Klingeler, Rüdiger; Koo, Changhyun; Lan, Yanhua; Müller, Dennis; Park, Jaena; Powell, Annie; Riley, Mark J; Wadepohl, Hubert

    2015-12-01

    A series of seven isostructural homodinuclear lanthanide complexes are reported. The magnetic properties (ac and dc SQUID measurements) are discussed on the basis of the X-ray structural properties which show that the two lanthanide sites are structurally different. MCD spectroscopy of the dysprosium(III) and neodymium(III) complexes ([Dy(III)2(L)(OAc)4](+) and [Nd(III)2(L)(OAc)4](+)) allowed us to thoroughly analyze the ligand field, and high-frequency EPR spectroscopy of the gadolinium(III) species ([Gd(III)2(L)(OAc)4](+)) showed the importance of dipolar coupling in these systems. An extensive quantum-chemical analysis of the dysprosium(III) complex ([Dy(III)2(L)(OAc)4](+)), involving an ab initio (CASSCF) wave function, explicit spin-orbit coupling (RASSI-SO), and a ligand field analysis (Lines model and Stevens operators), is in full agreement with all experimental data (SQUID, HF-EPR, MCD) and specifically allowed us to accurately simulate the experimental χT versus T data, which therefore allowed us to establish a qualitative model for all relaxation pathways. PMID:26588004

  6. Lanthanide(III) complexation with an amide derived pyridinophane.

    PubMed

    Castro, Goretti; Bastida, Rufina; Macías, Alejandro; Pérez-Lourido, Paulo; Platas-Iglesias, Carlos; Valencia, Laura

    2015-02-16

    Herein we report a detailed investigation of the solid state and solution structures of lanthanide(III) complexes with the 18-membered pyridinophane ligand containing acetamide pendant arms TPPTAM (TPPTAM = 2,2',2″-(3,7,11-triaza-1,5,9(2,6)-tripyridinacyclododecaphane-3,7,11-triyl)triacetamide). The ligand crystallizes in the form of a clathrated hydrate, where the clathrated water molecule establishes hydrogen-bonding interactions with the amide NH groups and two N atoms of the macrocycle. The X-ray structures of 13 different Ln(3+) complexes obtained as the nitrate salts (Ln(3+) = La(3+)-Yb(3+), except Pm(3+)) have been determined. Additionally, the X-ray structure of the La(3+) complex obtained as the triflate salt was also obtained. In all cases the ligand provides 9-fold coordination to the Ln(3+) ion, ten coordination being completed by an oxygen atom of a coordinated water molecule or a nitrate or triflate anion. The bond distances of the metal coordination environment show a quadratic change along the lanthanide series, as expected for isostructural series of Ln(3+) complexes. Luminescence lifetime measurements obtained from solutions of the Eu(3+) and Tb(3+) complexes in H2O and D2O point to the presence of a water molecule coordinated to the metal ion in aqueous solutions. The analysis of the Ln(3+)-induced paramagnetic shifts indicates that the complexes are ten-coordinated throughout the lanthanide series from Ce(3+) to Yb(3+), and that the solution structure is very similar to the structures observed in the solid state. The complexes of the light Ln(3+) ions are fluxional due to a fast Δ(λλλλλλ) ↔ Λ(δδδδδδ) interconversion that involves the inversion of the macrocyclic ligand and the rotation of the acetamide pendant arms. The complexes of the small Ln(3+) ions are considerably more rigid, the activation free energy determined from VT (1)H NMR for the Lu(3+) complex being ΔG(⧧)298 = 72.4 ± 5.1 kJ mol(-1).

  7. Radiolysis and Ageing of C2-BTP in Cinnamaldehyde/Hexanol Mixtures

    SciTech Connect

    Fermvik, Anna; Ekberg, Christian; Retegan, Teodora; Skarnemark, Gunnar

    2007-07-01

    The separation of actinides from lanthanides is an important step in the alternative methods for nuclear waste treatment currently under development. Polycyclic molecules containing nitrogen are synthesised and used for solvent extraction. A potential problem in the separation process is the degradation of the molecule due to irradiation or ageing. An addition of nitrobenzene has proved to have an inhibitory effect on degradation when added to a system containing C2-BTP in hexanol before irradiation. In this study, 2,6-di(5,6-diethyl-1,2,4-triazine-3-yl)pyridine (C2-BTP) was dissolved in different mixtures of cinnamaldehyde and hexanol and the effects on extraction after ageing and irradiation were investigated. Similar to nitrobenzene, cinnamaldehyde contains an aromatic ring which generally has a relatively high resistance towards radiolysis. Both C2-BTP in cinnamaldehyde and C2-BTP in hexanol seem to degrade with time. The system with C2-BTP in pure hexanol is relatively stable up to 17 days but then starts slowly to degrade. The solution with pure cinnamaldehyde as diluent started to degrade after only {approx}20 hours. The opposite is true for degradation caused by radiolysis; hexanol systems are more sensitive to radiolysis than cinnamaldehyde systems. Most of the radiolytic degradation took place during the first days of irradiation, up to a dose of 4 kGy. (authors)

  8. Effect of Lanthanide Complex Structure on Cell Viability and Association

    PubMed Central

    2015-01-01

    A systematic study of the effect of hydrophobicity and charge on the cell viability and cell association of lanthanide metal complexes is presented. The terbium luminescent probes feature a macrocyclic polyaminocarboxylate ligand (DOTA) in which the hydrophobicity of the antenna and that of the carboxyamide pendant arms are independently varied. Three sensitizing antennas were investigated in terms of their function in vitro: 2-methoxyisophthalamide (IAM(OMe)), 2-hydroxyisophthalamide (IAM), and 6-methylphenanthridine (Phen). Of these complexes, Tb-DOTA-IAM exhibited the highest quantum yield, although the higher cell viability and more facile synthesis of the structurally related Tb-DOTA-IAM(OMe) platform renders it more attractive. Further modification of this latter core structure with carboxyamide arms featuring hydrophobic benzyl, hexyl, and trifluoro groups as well as hydrophilic amino acid based moieties generated a family of complexes that exhibit high cell viability (ED50 > 300 μM) regardless of the lipophilicity or the overall complex charge. Only the hexyl-substituted complex reduced cell viability to 60% in the presence of 100 μM complex. Additionally, cellular association was investigated by ICP-MS and fluorescence microscopy. Surprisingly, the hydrophobic moieties did not increase cell association in comparison to the hydrophilic amino acid derivatives. It is thus postulated that the hydrophilic nature of the 2-methoxyisophthalamide antenna (IAM(OMe)) disfavors the cellular association of these complexes. As such, responsive luminescent probes based on this scaffold would be appropriate for the detection of extracellular species. PMID:24901440

  9. Highly Luminescent Lanthanide Complexes of 1 Hydroxy-2-pyridinones

    SciTech Connect

    University of California, Berkeley; Lawrence National Laboratory; Raymond, Kenneth; Moore, Evan G.; Xu, Jide; Jocher, Christoph J.; Castro-Rodriguez, Ingrid; Raymond, Kenneth N.

    2007-11-01

    The synthesis, X-ray structure, stability, and photophysical properties of several trivalent lanthanide complexes formed from two differing bis-bidentate ligands incorporating either alkyl or alkyl ether linkages and featuring the 1-hydroxy-2-pyridinone (1,2-HOPO) chelate group in complex with Eu(III), Sm(III) and Gd(III) are reported. The Eu(III) complexes are among some of the best examples, pairing highly efficient emission ({Phi}{sub tot}{sup Eu} {approx} 21.5%) with high stability (pEu {approx} 18.6) in aqueous solution, and are excellent candidates for use in biological assays. A comparison of the observed behavior of the complexes with differing backbone linkages shows remarkable similarities, both in stability and photophysical properties. Low temperature photophysical measurements for a Gd(III) complex were also used to gain insight into the electronic structure, and were found to agree with corresponding TD-DFT calculations for a model complex. A comparison of the high resolution Eu(III) emission spectra in solution and from single crystals also revealed a more symmetric coordination geometry about the metal ion in solution due to dynamic rotation of the observed solid state structure.

  10. Fluoride Binding and Crystal-Field Analysis of Lanthanide Complexes of Tetrapicolyl-Appended Cyclen.

    PubMed

    Blackburn, Octavia A; Kenwright, Alan M; Jupp, Andrew R; Goicoechea, Jose M; Beer, Paul D; Faulkner, Stephen

    2016-06-20

    Lanthanide complexes of tetrapicolyl cyclen displayed remarkably high affinities for fluoride (log K≈5) in water, and were shown to form 1:1 complexes. The behaviour of these systems can be rationalised by changes to the magnitude of the crystal-field parameter, B20 . However, such changes are not invariably accompanied by a change in sign of this parameter: for early lanthanides, the N8 donor set with a coordinated axial water molecule ensures that the magnetic anisotropy has the opposite sense to that observed in the analogous dehydrated lanthanide complexes. PMID:27167830

  11. Zirconium(IV)-Benzene Phosphonate Coordination Polymers: Lanthanide and Actinide Extraction and Thermal Properties.

    PubMed

    Luca, Vittorio; Tejada, Juan J; Vega, Daniel; Arrachart, Guilhem; Rey, Cyrielle

    2016-08-15

    Coordination polymers with different P/(Zr + P) molar ratios were prepared by combining aqueous solutions of Zr(IV) and benzenephosphonate derivatives. 1,3,5-Benzenetrisphosphonic acid (BTP) as well as phosphonocarboxylate derivatives in which carboxylate substitutes one or two of the phosphonate groups were chosen as the building blocks. The precipitates obtained on combining the two solutions were not X-ray amorphous but rather were indicative of poorly ordered materials. Hydrothermal treatment did not alter the structure of the materials produced but did result in improved crystalline order. The use of HF as a mineralizing agent during hydrothermal synthesis resulted in the crystallization of at least three relatively crystalline phases whose structure could not be determined owing to the complexity of the diffraction patterns. Gauging from the similarity of the diffraction patterns of all the phases, the poorly ordered precipitates and crystalline materials appeared to have similar underlying structures. The BTP-based zirconium phosphonates all showed a higher selectivity for lanthanides and thorium compared with cations such as Cs(+), Sr(2+), and Co(2+). Substitution of phosphonate groups by carboxylate groups did little to alter the pattern of selectivity implying that selectivity in the system was entirely determined by the -POH group with little influence from the -COOH groups. Samples with the highest phosphorus content showed the highest extraction efficiencies for lanthanide elements, especially the heavy lanthanides such as Dy(3+) and Ho(3+) with separation factors of around four with respect to La(3+). In highly acid solutions (4 M HNO3) there was a pronounced variation in extraction efficiency across the lanthanide series. In situ, nonambient diffraction was performed on ZrBTP-0.8 loaded with Th, Ce, and a complex mixture of lanthanides. In all cases the crystalline Zr2P2O7 pyrophosphate phase was formed at ∼800 °C demonstrating the versatility of

  12. Zirconium(IV)-Benzene Phosphonate Coordination Polymers: Lanthanide and Actinide Extraction and Thermal Properties.

    PubMed

    Luca, Vittorio; Tejada, Juan J; Vega, Daniel; Arrachart, Guilhem; Rey, Cyrielle

    2016-08-15

    Coordination polymers with different P/(Zr + P) molar ratios were prepared by combining aqueous solutions of Zr(IV) and benzenephosphonate derivatives. 1,3,5-Benzenetrisphosphonic acid (BTP) as well as phosphonocarboxylate derivatives in which carboxylate substitutes one or two of the phosphonate groups were chosen as the building blocks. The precipitates obtained on combining the two solutions were not X-ray amorphous but rather were indicative of poorly ordered materials. Hydrothermal treatment did not alter the structure of the materials produced but did result in improved crystalline order. The use of HF as a mineralizing agent during hydrothermal synthesis resulted in the crystallization of at least three relatively crystalline phases whose structure could not be determined owing to the complexity of the diffraction patterns. Gauging from the similarity of the diffraction patterns of all the phases, the poorly ordered precipitates and crystalline materials appeared to have similar underlying structures. The BTP-based zirconium phosphonates all showed a higher selectivity for lanthanides and thorium compared with cations such as Cs(+), Sr(2+), and Co(2+). Substitution of phosphonate groups by carboxylate groups did little to alter the pattern of selectivity implying that selectivity in the system was entirely determined by the -POH group with little influence from the -COOH groups. Samples with the highest phosphorus content showed the highest extraction efficiencies for lanthanide elements, especially the heavy lanthanides such as Dy(3+) and Ho(3+) with separation factors of around four with respect to La(3+). In highly acid solutions (4 M HNO3) there was a pronounced variation in extraction efficiency across the lanthanide series. In situ, nonambient diffraction was performed on ZrBTP-0.8 loaded with Th, Ce, and a complex mixture of lanthanides. In all cases the crystalline Zr2P2O7 pyrophosphate phase was formed at ∼800 °C demonstrating the versatility of

  13. Photo-reactive charge trapping memory based on lanthanide complex

    PubMed Central

    Zhuang, Jiaqing; Lo, Wai-Sum; Zhou, Li; Sun, Qi-Jun; Chan, Chi-Fai; Zhou, Ye; Han, Su-Ting; Yan, Yan; Wong, Wing-Tak; Wong, Ka-Leung; Roy, V. A. L.

    2015-01-01

    Traditional utilization of photo-induced excitons is popularly but restricted in the fields of photovoltaic devices as well as photodetectors, and efforts on broadening its function have always been attempted. However, rare reports are available on organic field effect transistor (OFET) memory employing photo-induced charges. Here, we demonstrate an OFET memory containing a novel organic lanthanide complex Eu(tta)3ppta (Eu(tta)3 = Europium(III) thenoyltrifluoroacetonate, ppta = 2-phenyl-4,6-bis(pyrazol-1-yl)-1,3,5-triazine), in which the photo-induced charges can be successfully trapped and detrapped. The luminescent complex emits intense red emission upon ultraviolet (UV) light excitation and serves as a trapping element of holes injected from the pentacene semiconductor layer. Memory window can be significantly enlarged by light-assisted programming and erasing procedures, during which the photo-induced excitons in the semiconductor layer are separated by voltage bias. The enhancement of memory window is attributed to the increasing number of photo-induced excitons by the UV light. The charges are stored in this luminescent complex for at least 104 s after withdrawing voltage bias. The present study on photo-assisted novel memory may motivate the research on a new type of light tunable charge trapping photo-reactive memory devices. PMID:26449199

  14. Photo-reactive charge trapping memory based on lanthanide complex.

    PubMed

    Zhuang, Jiaqing; Lo, Wai-Sum; Zhou, Li; Sun, Qi-Jun; Chan, Chi-Fai; Zhou, Ye; Han, Su-Ting; Yan, Yan; Wong, Wing-Tak; Wong, Ka-Leung; Roy, V A L

    2015-01-01

    Traditional utilization of photo-induced excitons is popularly but restricted in the fields of photovoltaic devices as well as photodetectors, and efforts on broadening its function have always been attempted. However, rare reports are available on organic field effect transistor (OFET) memory employing photo-induced charges. Here, we demonstrate an OFET memory containing a novel organic lanthanide complex Eu(tta)3ppta (Eu(tta)3 = Europium(III) thenoyltrifluoroacetonate, ppta = 2-phenyl-4,6-bis(pyrazol-1-yl)-1,3,5-triazine), in which the photo-induced charges can be successfully trapped and detrapped. The luminescent complex emits intense red emission upon ultraviolet (UV) light excitation and serves as a trapping element of holes injected from the pentacene semiconductor layer. Memory window can be significantly enlarged by light-assisted programming and erasing procedures, during which the photo-induced excitons in the semiconductor layer are separated by voltage bias. The enhancement of memory window is attributed to the increasing number of photo-induced excitons by the UV light. The charges are stored in this luminescent complex for at least 10(4) s after withdrawing voltage bias. The present study on photo-assisted novel memory may motivate the research on a new type of light tunable charge trapping photo-reactive memory devices.

  15. Photo-reactive charge trapping memory based on lanthanide complex

    NASA Astrophysics Data System (ADS)

    Zhuang, Jiaqing; Lo, Wai-Sum; Zhou, Li; Sun, Qi-Jun; Chan, Chi-Fai; Zhou, Ye; Han, Su-Ting; Yan, Yan; Wong, Wing-Tak; Wong, Ka-Leung; Roy, V. A. L.

    2015-10-01

    Traditional utilization of photo-induced excitons is popularly but restricted in the fields of photovoltaic devices as well as photodetectors, and efforts on broadening its function have always been attempted. However, rare reports are available on organic field effect transistor (OFET) memory employing photo-induced charges. Here, we demonstrate an OFET memory containing a novel organic lanthanide complex Eu(tta)3ppta (Eu(tta)3 = Europium(III) thenoyltrifluoroacetonate, ppta = 2-phenyl-4,6-bis(pyrazol-1-yl)-1,3,5-triazine), in which the photo-induced charges can be successfully trapped and detrapped. The luminescent complex emits intense red emission upon ultraviolet (UV) light excitation and serves as a trapping element of holes injected from the pentacene semiconductor layer. Memory window can be significantly enlarged by light-assisted programming and erasing procedures, during which the photo-induced excitons in the semiconductor layer are separated by voltage bias. The enhancement of memory window is attributed to the increasing number of photo-induced excitons by the UV light. The charges are stored in this luminescent complex for at least 104 s after withdrawing voltage bias. The present study on photo-assisted novel memory may motivate the research on a new type of light tunable charge trapping photo-reactive memory devices.

  16. Molecular magnets based on homometallic hexanuclear lanthanide(III) complexes.

    PubMed

    Das, Sourav; Hossain, Sakiat; Dey, Atanu; Biswas, Sourav; Sutter, Jean-Pascal; Chandrasekhar, Vadapalli

    2014-05-19

    The reaction of lanthanide(III) chloride salts (Gd(III), Dy(III), Tb(III), and Ho(III)) with the hetero donor chelating ligand N'-(2-hydroxy-3-methoxybenzylidene)-6-(hydroxymethyl)picolinohydrazide (LH3) in the presence of triethylamine afforded the hexanuclear Ln(III) complexes [{Ln6(L)2(LH)2}(μ3-OH)4][MeOH]p[H2O]q[Cl]4·xH2O·yCH3OH (1, Ln = Gd(III), p = 4, q = 4, x = 8, y = 2; 2, Ln = Dy(III), p = 2, q = 6, x = 8, y = 4; 3, Ln = Tb(III), p = 2, q = 6, x = 10, y = 4; 4, Ln = Ho(III), p = 2, q = 6, x = 10, y = 2). X-ray diffraction studies revealed that these compounds possess a hexanuclear [Ln6(OH)4](14+) core consisting of four fused [Ln3(OH)](8+) subunits. Both static (dc) and dynamic (ac) magnetic properties of 1-4 have been studied. Single-molecule magnetic behavior has been observed in compound 2 with an effective energy barrier and relaxation time pre-exponential parameters of Δ/kB = 46.2 K and τ0 = 2.85 × 10(-7) s, respectively. PMID:24766539

  17. Carbon bridged triphenolate lanthanide complexes: synthesis, characterization, DFT studies and catalytic activities for isoprene polymerization.

    PubMed

    Zhang, Min; Liang, Zhenhua; Ling, Jun; Ni, Xufeng; Shen, Zhiquan

    2015-06-28

    The dinuclear lanthanide complexes [Ln2(L)2(THF)n] (Ln = Nd (1) n = 4, Gd (2) n = 3, Lu (3) n = 2) supported by carbon bridged triphenolate ligands [LH3 = tris(3,5-di-tert-butyl-2-hydroxyphenyl)methane] were synthesized via a salt metathesis reaction between lanthanide trichlorides and LNa3 in THF. All complexes were characterized by elemental analysis and X-ray crystallography, and complex 3 was characterized by (1)H and (13)C NMR spectroscopy. Agostic interactions were found in these complexes and were further substantiated by DFT calculations of complex 3. These lanthanide complexes in combination with aluminum alkyls and [Ph3C](+)[B(C6F5)4](-) generated efficient homogeneous catalysts for the cis-1,4 polymerization of isoprene, with complex 1 having the best catalytic activity. PMID:26008592

  18. A lanthanide complex for metal encapsulations and anion exchanges.

    PubMed

    Sun, Yan-Qiong; Wan, Fang; Li, Xin-Xiong; Lin, Jian; Wu, Tao; Zheng, Shou-Tian; Bu, Xianhui

    2016-08-01

    A cationic lanthanide metalloligand with 3 dangling carboxylate groups on its periphery co-assembles with nitrate into a porous thermochromic solid responsive to both external cations and anions, owing to the presence of exchangeable NO3(-) as well as cation cavities arising from cooperative orientation of free carboxylate groups. An especially interesting feature is the structural memory effect during crystallization exhibited by the metalloligand, even after dissolution and binding to secondary cations (Cu(2+), Cd(2+)…). Moreover, the porous solid can undergo ion-exchange with various anions, leading to tunable thermochromic temperature and color range. PMID:27463609

  19. Versatile allosteric molecular devices based on reversible formation of luminous lanthanide complexes.

    PubMed

    Kitamura, Yusuke; Yamamoto, Shikinari; Osawa, Yuka; Matsuura, Hirotaka; Ihara, Toshihiro

    2013-01-11

    A versatile molecular device (lanthanide-complex molecular beacon; LCMB) was prepared by tethering ethylenediaminetetraacetic acid to the 5'-end and 1,10-phenanthroline to the 3'-end of stem-loop structured DNA as metal-capturing and sensitizer moieties, respectively. The emission from LCMB responded to the target molecule through the reversible structural change.

  20. Homodinuclear lanthanide complexes of phenylthiopropionic acid: synthesis, characterization, cytotoxicity, DNA cleavage, and antimicrobial activity.

    PubMed

    Shiju, C; Arish, D; Kumaresan, S

    2013-03-15

    Lanthanide complexes of La(III), Pr(III), Nd(III), Sm(III), and Ho(III) with phenylthiopropionic acid were synthesized and characterized by elemental analysis, mass, IR, electronic spectra, molar conductance, TGA, and powder XRD. The results show that the lanthanide complexes are homodinuclear in nature. The two lanthanide ions are bridged by eight oxygen atoms from four carboxylate groups. Thermal decomposition profiles are consistent with the proposed formulations. Powder XRD studies show that all the complexes are amorphous in nature. Antimicrobial studies indicate that these complexes exhibit more activity than the ligand itself. The DNA cleavage activity of the ligand and its complexes were assayed on Escherichia coli DNA using gel electrophoresis in the presence of H(2)O(2). The result shows that the Pr(III) and Nd(III) complexes have completely cleaved the DNA. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa) and colon cancer cells (HCT116) and it was found that the La(III) and Nd(III) complexes are more active than the corresponding Pr(III), Sm(III), Ho(III) complexes, and the free ligand on both the cancer cells.

  1. Homodinuclear lanthanide complexes of phenylthiopropionic acid: Synthesis, characterization, cytotoxicity, DNA cleavage, and antimicrobial activity

    NASA Astrophysics Data System (ADS)

    Shiju, C.; Arish, D.; Kumaresan, S.

    2013-03-01

    Lanthanide complexes of La(III), Pr(III), Nd(III), Sm(III), and Ho(III) with phenylthiopropionic acid were synthesized and characterized by elemental analysis, mass, IR, electronic spectra, molar conductance, TGA, and powder XRD. The results show that the lanthanide complexes are homodinuclear in nature. The two lanthanide ions are bridged by eight oxygen atoms from four carboxylate groups. Thermal decomposition profiles are consistent with the proposed formulations. Powder XRD studies show that all the complexes are amorphous in nature. Antimicrobial studies indicate that these complexes exhibit more activity than the ligand itself. The DNA cleavage activity of the ligand and its complexes were assayed on Escherichia coli DNA using gel electrophoresis in the presence of H2O2. The result shows that the Pr(III) and Nd(III) complexes have completely cleaved the DNA. The anticancer activities of the complexes have also been studied towards human cervical cancer cell line (HeLa) and colon cancer cells (HCT116) and it was found that the La(III) and Nd(III) complexes are more active than the corresponding Pr(III), Sm(III), Ho(III) complexes, and the free ligand on both the cancer cells.

  2. Structural, Magnetic and Luminescent Properties of Lanthanide Complexes with N-Salicylideneglycine

    PubMed Central

    Vančo, Ján; Trávníček, Zdeněk; Kozák, Ondřej; Boča, Roman

    2015-01-01

    A series of anionic heavy lanthanide complexes, involving the N-salicylideneglycinato(2-) Schiff base ligand (salgly) and having the general formula K[Ln(salgly)2(H2O)2]∙H2O (1–6), where Ln stands for Gd, Tb, Dy, Ho, Er and Tm, was prepared using the one-pot template synthesis. The complexes were thoroughly characterized by elemental and Thermogravimetric/Differential Thermal Analyses (TG/DTA), Fourier Transform Infrared Spectroscopy (FT-IR), and photoluminescence spectroscopies, electrospray-ionization mass spectrometry, and their magnetic properties were studied by temperature-dependent dc magnetic measurements using the superconducting quantum interference device (SQUID). The X-ray structure of the terbium(III) complex (2), representing the unique structure between the lanthanide complexes of N-salicylideneamino acids, was determined. The results of spectral and structural studies revealed the isostructural nature of the prepared complexes, in which the lanthanide ion is octacoordinated by two O,N,O-donor salgly ligands and two aqua ligands. The analysis of magnetic data confirmed that the complexes behave as paramagnets obeying the Curie law. The results of photoluminescence spectral studies of the complexes showed the different origin in their luminescent properties between the solid state and solution. An antenna effect of the Schiff base ligand was observed in a powder form of the complex only, while it acts as a fluorophore in a solution. PMID:25927576

  3. Structural, magnetic and luminescent properties of lanthanide complexes with N-salicylideneglycine.

    PubMed

    Vančo, Ján; Trávníček, Zdeněk; Kozák, Ondřej; Boča, Roman

    2015-01-01

    A series of anionic heavy lanthanide complexes, involving the N-salicylideneglycinato(2-) Schiff base ligand (salgly) and having the general formula K[Ln(salgly)₂(H₂O)₂]∙H₂O (1-6), where Ln stands for Gd, Tb, Dy, Ho, Er and Tm, was prepared using the one-pot template synthesis. The complexes were thoroughly characterized by elemental and Thermogravimetric/Differential Thermal Analyses (TG/DTA), Fourier Transform Infrared Spectroscopy (FT-IR), and photoluminescence spectroscopies, electrospray-ionization mass spectrometry, and their magnetic properties were studied by temperature-dependent dc magnetic measurements using the superconducting quantum interference device (SQUID). The X-ray structure of the terbium(III) complex (2), representing the unique structure between the lanthanide complexes of N-salicylideneamino acids, was determined. The results of spectral and structural studies revealed the isostructural nature of the prepared complexes, in which the lanthanide ion is octacoordinated by two O,N,O-donor salgly ligands and two aqua ligands. The analysis of magnetic data confirmed that the complexes behave as paramagnets obeying the Curie law. The results of photoluminescence spectral studies of the complexes showed the different origin in their luminescent properties between the solid state and solution. An antenna effect of the Schiff base ligand was observed in a powder form of the complex only, while it acts as a fluorophore in a solution. PMID:25927576

  4. Lanthanide complexes as luminogenic probes to measure sulfide levels in industrial samples.

    PubMed

    Thorson, Megan K; Ung, Phuc; Leaver, Franklin M; Corbin, Teresa S; Tuck, Kellie L; Graham, Bim; Barrios, Amy M

    2015-10-01

    A series of lanthanide-based, azide-appended complexes were investigated as hydrogen sulfide-sensitive probes. Europium complex 1 and Tb complex 3 both displayed a sulfide-dependent increase in luminescence, while Tb complex 2 displayed a decrease in luminescence upon exposure to NaHS. The utility of the complexes for monitoring sulfide levels in industrial oil and water samples was investigated. Complex 3 provided a sensitive measure of sulfide levels in petrochemical water samples (detection limit ∼ 250 nM), while complex 1 was capable of monitoring μM levels of sulfide in partially refined crude oil. PMID:26482000

  5. A series of binuclear lanthanide(III) complexes: Crystallography, antimicrobial activity and thermochemistry properties studies

    NASA Astrophysics Data System (ADS)

    Zhang, Ying-Ying; Ren, Ning; Xu, Su-Ling; Zhang, Jian-Jun; Zhang, Da-Hai

    2015-02-01

    A series of novel lanthanide complexes with the general formula [Ln(3,4-DClBA)3phen]2 (Ln = Ho(1), Nd(2), Sm(3), Dy(4), Eu(5), Tb(6), Yb(7) and Er(8), 3,4-DClBA = 3,4-dichlorobenzoate, phen = 1,10-phenanthroline) were prepared at room temperature and characterized. The crystal structures of complexes 1-8 have been determined by single crystal X-ray diffraction. These complexes are isomorphous and lanthanide ions are all eight-coordinated to oxygen atoms and nitrogen atoms with distorted square-antiprism geometry. The thermal decomposition mechanism and TG-FTIR spectra of gaseous products of thermal decomposition processes for complexes 1-8 were acquired through TG/DSC-FTIR system. The heat capacities of complexes 1-8 were measured using DSC technology and fitted to a polynomial equation by the least-squares method. Complexes 3-6 display characteristic lanthanide emission bands in the visible region. Meanwhile, these complexes exhibit in good antimicrobial activity against Candida albicans, Escherichia coli, and Staphylococcus aureu.

  6. Synthesis and bright luminescence of lanthanide (Eu(III), Tb(III)) complexes sensitized with a novel organic ligand

    NASA Astrophysics Data System (ADS)

    An, Bao-Li; Gong, Meng-Lian; Cheah, Kok-Wai; Zhang, Ji-Ming; Li, King-Fai

    2004-02-01

    A novel organic ligand, 6-[(benzylamino) carbonyl]-2-pyridine carboxylic acid (HBAP), and the corresponding lanthanide complexes, tris(6-[(benzylamino) carbonyl]- 2-pyridine carboxylato) lanthanide(III) (Ln-BAP, Ln=Eu, Tb, Gd), have been designed and synthesized. The lanthanide (Eu(III), Tb(III)) complexes were efficiently sensitized by BAP ligand. The fluorescence quantum yields were investigated by comparison with a luminescence standard, and the yields were 15 ± 3%, 34 ± 3% for the solid europium and terbium complexes respectively. The lowest triplet level of HBAP ligand was calculated from the phosphorescence spectrum of Gd-BAP complex, and the energy transfer mechanisms in the lanthanide complexes were discussed.

  7. EXAFS characterisation of metal bonding in highly luminescent, UV stable, water-soluble and biocompatible lanthanide complexes

    NASA Astrophysics Data System (ADS)

    Kalyakina, A.; Utochnikova, V.; Trigub, A.; Zubavichus, Y.; Kuzmina, N.; Bräse, S.

    2016-05-01

    The combination of X-ray diffraction with EXAFS was employed to assess the coordination environment of lanthanide complexes in solutions. This method is based on the assumption that the local structure of lanthanide complexes in solution combines elements of the crystal structure of the complex in the solid state (single- or polycrystalline) and the elements of the local structure of a lanthanide salt, completely dissociated in the solvent (usually chlorides). The success of this approach is demonstrated with the lanthanide (III) 2,3,4,5,6-pentafluorobenzoate complexes, where the local structure in aqueous and methanol solutions were estimated. Moreover, the dissociation degree of the complexes in aqueous and methanol solutions was evaluated.

  8. Study of Lanthanide Complexes with BTFA in Silica Gels by Photoacoustic Spectroscopy

    NASA Astrophysics Data System (ADS)

    Liu, R. Y.; Zhang, H. X.; Yang, Y. T.; Zhang, S. Y.; Liu, X. J.

    2016-06-01

    In this work, lanthanide β -diketonate complexes Ln(btfa){}3 \\cdot 2H2O (Ln^{3+}: Eu^{3+}, Sm^{3+ }, and Tb^{3+}; btfa: 4,4,4-trifluoro-l-phenyl-1,3-butanedione) were incorporated into silica gels by a sol-gel method. Photoacoustic (PA) spectra of these complex-doped silica samples were measured and studied. The PA intensity of the β -diketonate ligand is nearly the same for lanthanide complexes in wet gels. After heat treatment at 150°C, however, the PA intensity of the ligand increases for Eu^{3+}, Sm^{3+}, and Tb^{3+} complexes in silica gels, respectively. Different PA intensities of the samples are interpreted by comparison with their luminescence spectra. The luminescence result is consistent with the PA spectra. The result indicates that lanthanide β -diketonate complexes cannot be formed in silica gels without a suitable heat treatment. Moreover, the relaxation process model is proposed based on the PA and luminescence results.

  9. Physical characteristics of lanthanide complexes that act as magnetization transfer (MT) contrast agents

    NASA Astrophysics Data System (ADS)

    Zhang, Shanrong; Sherry, A. Dean

    2003-02-01

    Rapid water exchange is normally considered a prerequisite for efficient Gd 3+-based MRI contrast agents. Yet recent measures of exchange rates in some Gd 3+ complexes have shown that water exchange can become limiting when such complexes are attached to larger macromolecular structures. A new class of lanthanide complexes that display unusually slow water exchange (bound water lifetimes ( τM298) > 10 μs) has recently been reported. This apparent disadvantage may be taken advantage of by switching the metal ion from gadolinium(III) to a lanthanide that shifts the bound water resonance substantially away from bulk water. Given appropriate water exchange kinetics, one can then alter the intensity of the bulk water signal by selective presaturation of this highly shifted, Ln3+-bound water resonance. This provides the basis of a new method to alter MR image contrast in tissue. We have synthesized a variety of DOTA-tetra(amide) ligands to evaluate as potential magnetization transfer (MT) contrast agents and found that the bound water lifetimes in these complexes are sensitive to both ligand structure (a series of Eu 3+ complexes have τM298 values that range from 1 to 1300 μs) and the identity of the paramagnetic Ln3+ cation (from 3 to 800 μs for a single ligand). This demonstrates that it may be possible either to fine-tune the ligand structure or to select proper lanthanide cation to create an optimal MT agent for any clinical imaging field.

  10. Discrete site surface complexation constants for lanthanide adsorption to bacteria as determined by experiments and linear free energy relationships.

    PubMed

    Ngwenya, Bryne T; Magennis, Marisa; Olive, Valerie; Mosselmans, J Fred W; Ellam, Robert M

    2010-01-15

    Bacteria are abundant in many natural and engineered environments where they are thought to exert important controls on the cycling, mobility, bioavailability, and toxicity of metal contaminants. In order to probe their role in moderating the behavior of lanthanides, pH-dependent adsorption edges of 13 individual lanthanides and yttrium to the Gram-negative bacterium Pantoea agglomerans were used to generate discrete site surface complexation constants. The calculated surface complexation constants were compared with stability constants estimated using linear free energy relationships based on a number of hydroxyl-containing ligands. The experimental data suggests that lanthanide adsorption edges below pH 6.5 are consistent with adsorption to phosphate groups for the light and some of the middle lanthanides (La to Gd), whereas some of the middle and heavy lanthanides appear to favor carboxyl co-ordination (Tb to Yb), although exceptions occur in each grouping. The experimentally derived surface complexation constants for carboxyl coordination were of similar magnitude to stability constants estimated from linear free energy correlations using fulvic acid stability constants. The implication is that the adsorption of lanthanides to bacterial surfaces could be modeled reasonably well using lanthanide stability constants for natural organic matter, except perhaps at low pH where phosphate binding dominates. PMID:20000843

  11. Heterobimetallic dinuclear lanthanide alkoxide complexes as acid-base difunctional catalysts for transesterification.

    PubMed

    Zeng, Ruijie; Sheng, Hongting; Zhang, Yongcang; Feng, Yan; Chen, Zhi; Wang, Junfeng; Chen, Man; Zhu, Manzhou; Guo, Qingxiang

    2014-10-01

    A practical lanthanide(III)-catalyzed transesterification of carboxylic esters, weakly reactive carbonates, and much less-reactive ethyl silicate with primary and secondary alcohols was developed. Heterobimetallic dinuclear lanthanide alkoxide complexes [Ln2Na8{(OCH2CH2NMe2)}12(OH)2] (Ln = Nd (I), Sm (II), and Yb (III)) were used as highly active catalysts for this reaction. The mild reaction conditions enabled the transesterification of various substrates to proceed in good to high yield. Efficient activation of transesterification may be endowed by the above complexes as cooperative acid-base difunctional catalysts, which is proposed to be responsible for the higher reactivity in comparison with simple acid/base catalysts.

  12. Preparation, characterization and luminescent properties of lanthanide complexes with a new aryl amide bridging ligand

    NASA Astrophysics Data System (ADS)

    Li, Ya-Fei; Tang, Kuan-Zhen; Tang, Yu; Liu, Wei-Sheng; Tan, Min-Yu

    2008-12-01

    A new aryl amide type bridging ligand 1,4-bis{[(2'-benzylaminoformyl)phenoxyl]ethoxyl}benzene ( L) and its complexes with lanthanide ions (Ln = Pr, Nd, Sm, Eu, Gd, Tb, Dy, Er) were synthesized and characterized by elemental analysis, infrared spectra and electronic spectra. At the same time, the luminescent properties of the Sm, Eu, Tb and Dy complexes in solid state and the Tb complex in solvents were also investigated. At room temperature, these four complexes exhibited characteristic luminescence emissions of the central metal ions under UV light excitation and could be significant in the field of supramolecular photonic devices.

  13. Enantiomeric self-recognition in homo- and heterodinuclear macrocyclic lanthanide(III) complexes.

    PubMed

    Lisowski, Jerzy

    2011-06-20

    The controlled formation of lanthanide(III) dinuclear μ-hydroxo-bridged [Ln(2)L(2)(μ-OH)(2)X(2)](n+) complexes (where X = H(2)O, NO(3)(-), or Cl(-)) of the enantiopure chiral macrocycle L is reported. The (1)H and (13)C NMR resonances of these complexes have been assigned on the basis of COSY, NOESY, TOCSY, and HMQC spectra. The observed NOE connectivities confirm that the dimeric solid-state structure is retained in solution. The enantiomeric nature of the obtained chiral complexes and binding of hydroxide anions are reflected in their CD spectra. The formation of the dimeric complexes is accompanied by a complete enantiomeric self-recognition of the chiral macrocyclic units. The reaction of NaOH with a mixture of two different mononuclear lanthanide(III) complexes, [Ln(1)L](3+) and [Ln(2)L](3+), results in formation of the heterodinuclear [Ln(1)Ln(2)L(2)(μ-OH)(2)X(2)](n+) complexes as well as the corresponding homodinuclear complexes. The formation of the heterodinuclear complex is directly confirmed by the NOESY spectra of [EuLuL(2)(μ-OH)(2)(H(2)O)(2)](4+), which reveal close contacts between the macrocyclic unit containing the Eu(III) ion and the macrocyclic unit containing the Lu(III) ion. While the relative amounts of homo- and heterodinuclear complexes are statistical for the two lanthanide(III) ions of similar radii, a clear preference for the formation of heterodinuclear species is observed when the two mononuclear complexes contain lanthanide(III) ions of markedly different sizes, e.g., La(III) and Yb(III). The formation of heterodinuclear complexes is accompanied by the self-sorting of the chiral macrocyclic units based on their chirality. The reactions of NaOH with a pair of homochiral or racemic mononuclear complexes, [Ln(1)L(RRRR)](3+)/[Ln(2)L(RRRR)](3+), [Ln(1)L(SSSS)](3+)/[Ln(2)L(SSSS)](3+), or [Ln(1)L(rac)](3+)/[Ln(2)L(rac)](3+), results in mixtures of homochiral, homodinuclear and homochiral, heterodinuclear complexes. On the contrary, no

  14. Complexation of Lanthanides with Glutaroimide-dioxime: Binding Strength and Coordination Modes.

    PubMed

    Ansari, Seraj A; Yang, Yanqiu; Zhang, Zhicheng; Gagnon, Kevin J; Teat, Simon J; Luo, Shunzhong; Rao, Linfeng

    2016-02-01

    The complexation of lanthanides (Nd(3+) and Eu(3+)) with glutaroimide-dioxime (H2L), a cyclic imide dioxime ligand that has been found to form stable complexes with actinides (UO2(2+) and NpO2(+)) and transition metal ions (Fe(3+), Cu(2+), etc.), was studied by potentiometry, absorption spectrophotometry, luminescence spectroscopy, and microcalorimetry. Lanthanides form three successive complexes, M(HL)(2+), M(HL)L, and M(HL)2(+) (where M stands for Nd(3+)/Eu(3+) and HL(-) stands for the singly deprotonated ligand). The enthalpies of complexation, determined by microcalorimetry, show that the formation of these complexes is exothermic. The stability constants of Ln(3+)/H2L complexes are several orders of magnitude lower than that of the corresponding Fe(3+)/H2L complexes but are comparable with that of UO2(2+)/H2L complexes. A structure of Eu(3+)/H2L complex, identified by single-crystal X-ray diffractometry, shows that the ligand coordinates to Eu(3+) in a tridentate mode, via the two oxygen atoms of the oxime group and the nitrogen atom of the imide group. The relocation of protons of the oxime groups (-CH═N-OH) from the oxygen to the nitrogen atom, and the deprotonation of the imide group (-CH-NH-CH-) result in a conjugated system with delocalized electron density on the ligand (-O-N-C-N-C-N-O-) that forms strong complexes with the lanthanide ions. PMID:26765525

  15. Circulatory polarized luminescence studies of lanthanide aminopolycarboxylate complexes

    SciTech Connect

    Spaulding, L.A.L.

    1985-01-01

    The intermolecular energy transfer studies were conducted for the investigation of complexation phenomena among the Ln/APC complexes. The data indicated that these potentially hexadentate ligands formed monomeric complexes until pH 10.0. Luminescence and spectral studies have provided data concerning the structural nature of the Ln/APC complexes. Polymerization and steric requirements of the complex are presented in detail.

  16. First examples of ternary lanthanide 5-aminoisophthalate complexes: Hydrothermal syntheses and structures of lanthanide coordination polymers with 5-aminoisophthalate and oxalate

    NASA Astrophysics Data System (ADS)

    Liu, Chong-Bo; Wen, Hui-Liang; Tan, Sheng-Shui; Yi, Xiu-Guang

    2008-05-01

    Two new lanthanide coordination polymers with mixed-carboxylates, [Ln(OX)(HAPA)(H 2O)] n[Ln = Eu ( 1), Ho ( 2); H 2APA = 5-aminoisophthalic acid; OX = oxalate] were obtained by hydrothermal reactions, and characterized by single crystal X-ray diffraction, elemental analysis and IR spectra. Complexes 1 and 2 are both 3-D supramolecular structure, in which lanthanide ions are bridged by oxalate and 5-aminoisophthalate ligands forming 2-D metal-organic framework, and 2-D networks are further architectured to form 3-D supramolecular structures by hydrogen bonds. The two carboxylate groups of H 2APA ligand are all deprotonated and exhibit chelating and bridging bidentate coordination modes, respectively, and the amino group in HAPA presents - NH3+ in the titled complexes. The thermogravimetric analysis was carried out to examine the thermal stability of the titled complexes. And the photoluminescence property of 1 was investigated.

  17. Influence of Schiff base and lanthanide metals on the synthesis, stability, and reactivity of monoamido lanthanide complexes bearing two Schiff bases.

    PubMed

    Han, Fubin; Teng, Qiaoqiao; Zhang, Yong; Wang, Yaorong; Shen, Qi

    2011-03-21

    The monoamido lanthanide complexes stabilized by Schiff base ligand L(2)LnN(TMS)(2) (L = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH═N-8-C(9)H(6)N, Ln = Yb (1), Y (2), Eu (3), Nd (4), and La (5)) were synthesized in good yields by the reactions of Ln[N(TMS)(2)](3) with 1.8 equiv of HL in hexane at room temperature. It was found that the stability of 1-5 depends greatly on the size of the lanthanide metals with the increasing trend of Yb ≈ Y < Nd < La. The amine elimination of Ln[N(TMS)(2)](3) with the bulky bidentate Schiff base HL' (L' = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH═N-2,6-Pr(i)(2)-C(6)H(3)) afforded the monoamido lanthanide complexes L'(2)LnN(TMS)(2) (Ln = Yb (9), Y (10), Nd (11), and La (12)). While the amine elimination with the less bulky Schiff base HL'' (L'' = 3,5-Bu(t)(2)-2-(O)-C(6)H(2)CH═N-2,6-Me(2)-C(6)H(3)) yielded the desired monoamido complexes with the small metals of Y and Yb, L''(2)LnN(TMS)(2) (Ln = Yb (13) and Y (14)), and the more stable tris-Schiff base complexes with the large metals of La and Nd, yielded L''(3)Ln as the only product. Complexes 1-14 were fully characterized including X-ray crystal structural analysis. Complexes 1-5, 10, and 14 can serve as the efficient catalysts for addition of amines to carbodiimides, and the catalytic activity is greatly affected by the lanthanide metals with the active sequence of Yb < Y < Eu ≈ Nd ≈ La.

  18. In vitro studies of lanthanide complexes for the treatment of osteoporosis.

    PubMed

    Mawani, Yasmin; Cawthray, Jacqueline F; Chang, Stanley; Sachs-Barrable, Kristina; Weekes, David M; Wasan, Kishor M; Orvig, Chris

    2013-05-01

    Lanthanide ions, Ln(III), are of interest in the treatment of bone density disorders because they are found to accumulate preferentially in bone (in vivo), have a stimulatory effect on bone formation, and exhibit an inhibitory effect on bone degradation (in vitro), altering the homeostasis of the bone cycle. In an effort to develop an orally active lanthanide drug, a series of 3-hydroxy-4-pyridinone ligands were synthesized and eight of these ligands (H1 = 3-hydroxy-2-methyl-1-(2-hydroxyethyl)-4-pyridinone, H2 = 3-hydroxy-2-methyl-1-(3-hydroxypropyl)-4-pyridinone, H3 = 3-hydroxy-2-methyl-1-(4-hydroxybutyl)-4-pyridinone, H4 = 3-hydroxy-2-methyl-1-(2-hydroxypropyl)-4-pyridinone, H5 = 3-hydroxy-2-methyl-1-(1-hydroxy-3-methylbutan-2-yl)-4-pyridinone, H6 = 3-hydroxy-2-methyl-1-(1-hydroxybutan-2-yl)-4-pyridinone, H7 = 1-carboxymethyl-3-hydroxy-2-methyl-4-pyridinone, H8 = 1-carboxyethyl-3-hydroxy-2-methyl-4-pyridinone) were coordinated to Ln(3+) (Ln = La, Eu, Gd, Lu) forming stable tris-ligand complexes (LnL(3), L = 1(-), 2(-), 3(-), 4(-), 5(-), 6(-), 7(-) and 8(-)). The dissociation (pK(an)) and metal ligand stability constants (log β(n)) of the 3-hydroxy-4-pyridinones with La(3+) and Gd(3+) were determined by potentiometric titrations, which demonstrated that the 3-hydroxy-4-pyridinones form stable tris-ligand complexes with the lanthanide ions. One phosphinate-EDTA derivative (H(5)XT = bis[[bis(carboxymethyl)amino]methyl]phosphinate) was also synthesized and coordinated to Ln(3+) (Ln = La, Eu, Lu), forming the potassium salt of [Ln(XT)](2-). Cytotoxicity assays were carried out in MG-63 cells; all the ligands and metal complexes tested were observed to be non-toxic to this cell line. Studies to investigate the toxicity, cellular uptake and apparent permeability (P(app)) of the lanthanide ions were conducted in Caco-2 cells where it was observed that [La(XT)](2-) had the greatest cell uptake. Binding affinities of free lanthanide ions (Ln = La, Gd and Lu), metal

  19. New sandwich-type lanthanide complexes based on closed-macrocyclic Schiff base and phthalocyanine molecules.

    PubMed

    Gao, Feng; Feng, Xiaowan; Yang, Liu; Chen, Xiaoyu

    2016-04-25

    Two new sandwich-type lanthanide complexes with the general formula [(Pc)2Ln3(L)(OAc)(OCH3)2] (Ln(3+) = Dy(3+) () and Er(3+) ()) were successfully synthesized and structurally characterized based on closed-macrocyclic Schiff base and phthalocyanine molecules. The magnetic properties and structure-property relationship in this multi-decker system were investigated. Interestingly, the corresponding dysprosium complex shows typical single-molecule magnetic behavior with ferromagnetic dipole-dipole interactions and the slow relaxation of magnetization. PMID:27044594

  20. Brilliant Sm, Eu, Tb and Dy chiral lanthanide complexes withstrong circularly polarized luminescence

    SciTech Connect

    Petoud, Stephane; Muller, Gilles; Moore, Evan G.; Xu, Jide; Sokolnicki, Jurek; Riehl, James P.; Le, Uyen; Cohen, Seth M.; Raymond,Kenneth N.

    2006-07-10

    The synthesis, characterization and luminescent behavior of trivalent Sm, Eu, Dy and Tb complexes of two enantiomeric, octadentate, chiral, 2-hydroxyisophthalamide ligands are reported. These complexes are highly luminescent in solution. Functionalization of the achiral parent ligand with a chiral 1-phenylethylamine substituent on the open face of the complex in close proximity to the metal center yields complexes with strong circularly polarized luminescence (CPL) activity. This appears to be the first example of a system utilizing the same ligand architecture to sensitize four different lanthanide cations and display CPL activity. The luminescence dissymmetry factor, g{sub lum}, recorded for the Eu(III) complex is one of the highest values reported, and this is the first time the CPL effect has been demonstrated for a Sm(III) complex with a chiral ligand. The combination of high luminescence intensity with CPL activity should enable new bioanalytical applications of macromolecules in chiral environments.

  1. Synthesis, characterization and anticancer activities of two lanthanide(III) complexes with a nicotinohydrazone ligand

    NASA Astrophysics Data System (ADS)

    Xu, Zhou-Qin; Mao, Xian-Jie; Jia, Lei; Xu, Jun; Zhu, Tao-Feng; Cai, Hong-Xin; Bie, Hong-Yan; Chen, Ru-Hua; Ma, Tie-liang

    2015-12-01

    Two isostructural acylhydrazone based complexes, namely [Ce(penh)2(H2O)4](NO3)3·4H2O (1) and [Sm(penh)2(NO3)2](NO3)·C2H5OH (2) (penh = 2-acetylpyridine nicotinohydrazone), have been obtained and characterized by physico-chemical and spectroscopic methods. The ten-coordinated lanthanide metal ion in each complex is surrounded by two independent tridentate neutral acylhydrazones with two ON2 donor sets. The other four coordination oxygen atoms are from four water molecules and two bidentate nitrate anions for complexes 1 and 2, respectively, thus giving distorted bicapped square antiprism geometry. Both complexes have excellent antitumor activity towards human pancreatic cancer (PATU8988), human colorectal cancer (lovo) and human gastric cancer(SGC7901) cell line. Furthermore, the cell apoptosis of complex 1 is detected by AnnexinV/PI flow cytometry.

  2. The btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] binding motif: a new versatile terdentate ligand for supramolecular and coordination chemistry.

    PubMed

    Byrne, Joseph P; Kitchen, Jonathan A; Gunnlaugsson, Thorfinnur

    2014-08-01

    Ligands containing the btp [2,6-bis(1,2,3-triazol-4-yl)pyridine] motif have appeared with increasing regularity over the last decade. This class of ligands, formed in a one pot ‘click’ reaction, has been studied for various purposes, such as for generating d and f metal coordination complexes and supramolecular self-assemblies, and in the formation of dendritic and polymeric networks, etc. This review article introduces btp as a novel and highly versatile terdentate building block with huge potential in inorganic supramolecular chemistry. We will focus on the coordination chemistry of btp ligands with a wide range of metals, and how it compares with other classical pyridyl and polypyridyl based ligands, and then present a selection of applications including use in catalysis, enzyme inhibition, photochemistry, molecular logic and materials, e.g. polymers, dendrimers and gels. The photovoltaic potential of triazolium derivatives of btp and its interactions with anions will also be discussed.

  3. Complexation of Lanthanides with Nitrate at Variable Temperatures: Thermodynamics and Coordination Modes

    SciTech Connect

    Rao, Linfeng; Tian, Guoxin

    2008-12-10

    Complexation of neodymium(III) with nitrate was studied at variable temperatures (25, 40, 55 and 70 C) by spectrophotometry and microcalorimetry. The NdNO{sub 3}{sup 2+} complex is weak and becomes slightly stronger as the temperature is increased. The enthalpy of complexation at 25 C was determined by microcalorimetry to be small and positive, (1.5 {+-} 0.2) kJ {center_dot} mol{sup -1}, in good agreement with the trend of the stability constant at variable temperatures. Luminescence emission spectra and lifetime of Eu(III) in nitrate solutions suggest that inner-sphere and bidentate complexes form between trivalent lanthanides (Nd{sup 3+} and Eu{sup 3+}) and nitrate in aqueous solutions. Specific Ion Interaction approach (SIT) was used to obtain the stability constants of NdNO{sub 3}{sup 2+} at infinite dilution and variable temperatures.

  4. Effect of lanthanide contraction on the mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien): Syntheses and characterizations of lanthanide complexes with a tetraelenidoantimonate ligand

    SciTech Connect

    Zhao Jing; Liang Jingjing; Pan Yingli; Zhang Yong; Jia Dingxian

    2011-06-15

    Mixed polyamine systems Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) (Ln=lanthanide, en=ethylenediamine, dien=diethylenetriamine, trien=triethylenetetramine) were investigated under solvothermal conditions, and novel mixed-coordinated lanthanide(III) complexes [Ln(en){sub 2}(dien)({eta}{sup 2}-SbSe{sub 4})] (Ln=Ce(1a), Nd(1b)), [Ln(en){sub 2}(dien)(SbSe{sub 4})] (Ln=Sm(2a), Gd(2b), Dy(2c)), [Ln(en)(trien)({mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4})]{sub {infinity}} (Ln=Ce(3a), Nd(3b)) and [Sm(en)(trien)({eta}{sup 2}-SbSe{sub 4})] (4a) were prepared. Two structural types of lanthanide selenidoantimonates were obtained across the lanthanide series in both en+dien and en+trien systems. The tetrahedral anion [SbSe{sub 4}]{sup 3-} acts as a monodentate ligand mono-SbSe{sub 4}, a bidentate chelating ligand {eta}{sup 2}-SbSe{sub 4} or a tridentate bridging ligand {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} to the lanthanide(III) center depending on the Ln{sup 3+} ions and the mixed ethylene polyamines, indicating the effect of lanthanide contraction on the structures of the lanthanide(III) selenidoantimonates. The lanthanide selenidoantimonates exhibit semiconducting properties with E{sub g} between 2.08 and 2.51 eV. - Graphical Abstract: Two structural types of lanthanide(III) selenidoantimonates are formed in both en-dien and en-trien mixed polyamines across lanthanide series, indicating the lanthanide contraction effect on the structures of the lanthanide(III) selenidoantimonates. Highlights: > Two structural types of lanthanide selenidoantimonates are prepared across the lanthanide series in both Ln/Sb/Se/(en+dien) and Ln/Sb/Se/(en+trien) systems. > The [SbSe{sub 4}]{sup 3-} anion acts as a mono-SbSe{sub 4}, a {eta}{sup 2}-SbSe{sub 4} or a {mu}-{eta}{sup 1},{eta}{sup 2}-SbSe{sub 4} ligand to the Ln{sup 3+} ions. > The soft base ligand [SbSe{sub 4}]{sup 3-} can be controlled to coordinate to the Ln{sup 3+} ions with en+dien and en+trien as co-ligands.

  5. Lanthanide-cyclodextrin complexes as probes for elucidating optical purity by NMR spectroscopy

    SciTech Connect

    Wenzel, T.J.; Bogyo, M.S.; Lebeau, E.L. )

    1994-06-01

    A multidentate ligand is bonded to cyclodextrins by the reaction of diethylenetriaminepentaacetic dianhydride with 6-mono- and 2-mono(ethylenediamine) derivatives of cyclodextrin. Adding Dy(III) to the cyclodextrin derivatives enhances the enantiomeric resolution in the [sup 1]H NMR spectra of carbionoxamine maleate, doxylamine succinate, pheniramine maleate, propranolol hydrochloride, and tryptophan. The enhancement is more pronounced with the secondary derivative. The Dy(III)-induced shifts can be used to elucidate the geometry of cyclodextrin-substrate inclusion complexes. Lanthanide-induced shifts are reported for complexes of aspartame, tryptophan, propranolol, and 1-anilino-8-naphthalenesulfonate with cyclodextrins, and the relative magnitudes of the shifts agree with previously reported structures of the complexes. 37 refs., 9 figs., 5 tabs.

  6. Solid-state and solution-state coordination chemistry of lanthanide(III) complexes with α-hydroxyisobutyric acid.

    PubMed

    Chen, Xiao-Yan; Goff, George S; Ewing, William C; Scott, Brian L; Runde, Wolfgang

    2012-12-17

    Despite the wide range of applications of α-hydroxyisobutyric acid (HIBA) in biochemical processes, pharmaceutical formulations, and group and elemental separations of lanthanides and actinides, the structures and geometries of lanthanide-HIBA complexes are still not well understood. We reacted HIBA with lanthanides in aqueous solution at pH = 5 and synthesized 14 lanthanide-HIBA complexes of the formula [Ln(HIBA)(2)(H(2)O)(2)](NO(3))·H(2)O (Ln = La (1), Ce (2), Pr (3), Nd (4), Sm (5), Eu (6), Gd (7), Tb (8), Dy (9), Ho (10), Er (11), Tm (12), Yb (13), Lu (14)), isolating single crystals (1-7, 10, and 11) and powders (8, 9, and 12-14). Both single-crystal and powder X-ray diffraction studies reveal a two-dimensional extended structure across the entire lanthanide series. The environment around the eight-coordinated Ln(III) atom is best described as a distorted dodecahedron, where HIBA acts as a monoanionic tridentate ligand with one carboxylato oxygen atom and one hydroxyl oxygen atom chelating to one Ln(III) center. The carboxylato oxygen atom from a second HIBA ligand bridges to a neighboring Ln(III) atom to form a two-dimensional extended structure. While the coordination mode for HIBA is identical across the lanthanide series, three different structure types are found for La, Ce-Ho, and Er-Lu. Solution characterization using (13)C NMR further confirmed a single solution complex under the crystallization conditions. Raman and UV-vis-NIR absorbance and diffuse reflectance spectra of HIBA-Ln(III) complexes were also measured.

  7. Lanthanide-organic complexes based on polyoxometalates: Solvent effect on the luminescence properties

    SciTech Connect

    Tang Qun; Liu Shuxia; Liang Dadong; Ma Fengji; Ren Guojian; Wei Feng; Yang Yuan; Li Congcong

    2012-06-15

    A series of lanthanide-organic complexes based on polyoxometalates (POMs) [Ln{sub 2}(DNBA){sub 4}(DMF){sub 8}][W{sub 6}O{sub 19}] (Ln=La(1), Ce(2), Sm(3), Eu(4), Gd(5); DNBA=3,5-dinitrobenzoate; DMF=N,N-dimethylformamide) has been synthesized. These complexes consist of [W{sub 6}O{sub 19}]{sup 2-} and dimeric [Ln{sub 2}(DNBA){sub 4}(DMF){sub 8}]{sup 2+} cations. The luminescence properties of 4 are measured in solid state and different solutions, respectively. Notably, the emission intensity increases gradually with the increase of solvent permittivity, and this solvent effect can be directly observed by electrospray mass spectrometry (ESI-MS). The analyses of ESI-MS show that the eight coordinated solvent DMF units of dimeric cation are active. They can move away from dimeric cations and exchange with solvent molecules. Although the POM anions escape from 3D supramolecular network, the dimeric state structure of [Ln{sub 2}(DNBA){sub 4}]{sup 2+} remains unchanged in solution. The conservation of red luminescence is attributed to the maintenance of the aggregated state structures of dimeric cations. - Graphical abstract: 3D POMs-based lanthanide-organic complexes performed the solvent effect on the luminescence property. The origin of such solvent effect can be understood and explained on the basis of the existence of coordinated active sites by the studies of ESI-MS. Highlights: Black-Right-Pointing-Pointer The solvent effect on the luminescence property of POMs-based lanthanide-organic complexes. Black-Right-Pointing-Pointer ESI-MS analyses illuminate the correlation between the structure and luminescence property. Black-Right-Pointing-Pointer The dimeric cations have eight active sites of solvent coordination. Black-Right-Pointing-Pointer The aggregated state structure of dimer cation remains unchanged in solution. Black-Right-Pointing-Pointer Luminescence associating with ESI-MS is a new method for investigating the interaction of complex and solvent.

  8. Synthesis, structure and luminescence properties of lanthanide complex with a new tetrapodal ligand featuring salicylamide arms

    SciTech Connect

    Song Xueqin; Wen Xiaoguang; Liu Weisheng; Wang Daqi

    2010-01-15

    A new tetrapodal ligand 1,1,1-tetrakis{l_brace}[(2'-(2-furfurylaminoformyl))phenoxyl]methyl{r_brace}methane (L) has been prepared and their coordination chemistry with Ln{sup III} ions has been investigated. The structure of {l_brace}[Ln{sub 4}L{sub 3}(NO{sub 3}){sub 12}].H{sub 2}O{r_brace}{sub i}nfinity (Ln=Nd, Eu)] shows the binodal 4,3-connected three-dimensional interpenetration coordination polymers with topology of a (8{sup 6}){sub 3}(8{sup 3}){sub 4} notation. [DyL(NO{sub 3}){sub 3}(H{sub 2}O){sub 2}].0.5CH{sub 3}OH and [ErL(NO{sub 3}){sub 3}(H{sub 2}O) (CH{sub 3}OH)].CH{sub 3}COCH{sub 3} is a 1:1 mononuclear complex with interesting supramolecular features. The structure of [NdL(H{sub 2}O){sub 6}].3ClO{sub 4}.3H{sub 2}O is a 2:1 mononuclear complex which further self-assembled through hydrogen bond to form a three-dimensional supramolecular structures. The result presented here indicates that both subtle variation of the terminal group and counter anions can be applied in the modulation of the overall molecular structures of lanthanide complex of salicylamide derivatives due to the structure specialties of this type of ligand. The luminescence properties of the Eu{sup III} complex are also studied in detail. - Grapical Abstract: We present here a series of zero- to three-dimensional lanthanide coordination structures and luminescence properties of Eu(III) complex of a new tetrapodal ligand.

  9. Thermodynamic study of the complexation of trivalent actinide and lanthanide cations by ADPTZ, a tridentate N-donor ligand.

    PubMed

    Miguirditchian, Manuel; Guillaneux, Denis; Guillaumont, Dominique; Moisy, Philippe; Madic, Charles; Jensen, Mark P; Nash, Kenneth L

    2005-03-01

    To better understand the bonding in complexes of f-elements by polydentate N-donor ligands, the complexation of americium(III) and lanthanide(III) cations by 2-amino-4,6-di-(pyridin-2-yl)-1,3,5-triazine (ADPTZ) was studied using a thermodynamic approach. The stability constants of the 1:1 complexes in a methanol/water mixture (75/25 vol %) were determined by UV-visible spectrophotometry for every lanthanide(III) ion (except promethium), and yttrium(III) and americium(III) cations. The thermodynamic parameters (DeltaH degrees , DeltaS degrees) of complexation were determined from the temperature dependence of the stability constants and by microcalorimetry. The trends of the variations of DeltaG degrees , DeltaH degrees , and DeltaS degrees across the lanthanide series are compared with published results for other tridentate ligands and confirm strongly ionic bonding in the lanthanide-ADPTZ complexes. Comparison of the thermodynamic properties between the Am- and Ln-ADPTZ complexes highlights an increase in stability of the complexes by a factor of 20 in favor of the americium cation. This difference arises from a more exothermic reaction enthalpy in the case of Am, which is correlated with a greater degree of covalency in the americium-nitrogen bonds. Quantum chemistry calculations performed on a series of trivalent actinide and lanthanide-ADPTZ complexes support the experimental results, showing a slightly greater covalence in the actinide-ligand bonds that originates from a charge transfer from the ligand sigma orbitals to the 5f and 6d orbitals of the actinide ion. PMID:15732980

  10. Determination of tetracycline in milk by using nucleotide/lanthanide coordination polymer-based ternary complex.

    PubMed

    Tan, Hongliang; Ma, Chanjiao; Song, Yonghai; Xu, Fugang; Chen, Shouhui; Wang, Li

    2013-12-15

    The meta-organic coordination polymers have been emerged as fascinating nanomaterials because of their tunable nature. In this work, we employed lanthanide coordination polymer self-assembled from adenosine monophosphate (AMP) and europium ion (Eu(3+)) as receptor reagent and citrate (Cit) as ancillary ligand to construct a fluorescent sensor for the detection of tetracycline (Tc) in milk. The co-coordination of Cit and Tc with Eu(3+) on the surface of the coordination polymer AMP/Eu leads to the formation of ternary complex which emitted strong fluorescence due to the removal of coordinated water molecules and an intramolecular energy transfer from Tc to Eu(3+). The fluorescent intensity of Eu(3+) displayed a good linear response to Tc concentrations in the range of 0.1-20 μM with a detection limit of 60 nM. This method was successfully applied to determine the levels of Tc in milk, which is the first application of coordination polymer as a fluorescent sensor in real sample. Compared with other Eu(3+)-based fluorescent methods for Tc detection, the presented method allows simple, direct analysis of Tc without requiring special reaction media or complicated prepreparation processes. This straightforward strategy could be extended to the preparation of other lanthanide coordination polymer-based fluorescent probes for applications in biosensing, imaging, drug delivery, and so on.

  11. Sub-monolayer film growth of a volatile lanthanide complex on metallic surfaces

    PubMed Central

    Chen, Jinjie; Edelmann, Kevin; Wulfhekel, Wulf

    2015-01-01

    Summary We deposited a volatile lanthanide complex, tris(2,2,6,6-tetramethyl-3,5-heptanedionato)terbium(III), onto metal surfaces of Cu(111), Ag(111) and Au(111) in vacuum and observed well-ordered sub-monolayer films with low temperature (5 K) scanning tunneling microscopy. The films show a distorted three-fold symmetry with a commensurate structure. Scanning tunneling spectroscopy reveals molecular orbitals delocalized on the ligands of the molecule. Our results imply that this complex can be transferred onto the metal substrates without molecular decomposition or contamination of the surface. This new rare-earth-based class of molecules broadens the choice of molecular magnets to study with scanning tunneling microscopy. PMID:26733215

  12. A study of in vitro antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand

    PubMed Central

    Al Momani, Waleed Mahmoud; Taha, Ziyad Ahmed; Ajlouni, Abdulaziz Mahmoud; Shaqra, Qasem Mohammad Abu; Al Zouby, Muaz

    2013-01-01

    Objective To establish the antibacterial activity of lanthanides complexes with a tetradentate Schiff base ligand L. Methods (N, N′-bis (1-naphthaldimine)-o-phenylenediamine) was prepared from the condensation of 2-hydroxy-1-naphthaldehyde with o-phenylenediamine in a molar ratio of 2:1. The antimicrobial activity of the resultant Ln (III) complexes was investigated using agar well diffusion and micro-broth dilution techniques; the latter was used to establish the minimum inhibitory concentrations for each compound investigated. Results Most of Ln (III) complexes were found to exhibit antibacterial activities against a number of pathogenic bacteria with MICs ranging between 1.95-250.00 µg/mL. Staphylococcus aureus was the most susceptible bacterial species to [LaL(NO3)2(H2O)](NO3) complex while Shigella dysenteriae and Escherichia coli required a relatively higher MIC (250 µg/mL). The complexes La (III) and Pr (III) were effective inhibitors against Staphylococcus aureus, whereas Sm (III) complex was effective against Serratia marcescens. On the other hand, Gd (III), La (III) and Nd (III) were found to be more potent inhibitors against Pseudomonas aeruginosa than two of commonly used antibiotics. The remaining Ln (III) complexes showed no remarkable activity as compared to the two standard drugs used. Conclusions Tetradentate Schiff base ligand L and its complexes could be a potential antibacterial compounds after further investigation. PMID:23646299

  13. Increasing the luminescence of lanthanide(III) macrocyclic complexes by the use of polymers and lanthanide enhanced luminescence

    NASA Astrophysics Data System (ADS)

    Leif, Robert C.; Becker, Margie C.; Bromm, Alfred J., Jr.; Vallarino, Lidia M.; Williams, Steven A.; Yang, Sean

    2001-05-01

    A Eu (III)-macrocycle-isothiocyanate, Quantum DyeTM, has been reacted with lysine homo- and hetero-peptides to give polymers with multiple luminescent side chains. Contrary to the concentration quenching that occurs with conventional organic fluorophores, the attachment of multiple Quantum Dyes to a polymer results in a concomitant increase in luminescence. The emission intensity of the peptide-bound Quantum Dye units is approximately linearly related to their number. The attachment of peptides containing multiple lanthanide (III) macrocycles to analyte-binding species is facilitated by employing solid-phase technology. Bead-bound peptides are first labeled with multiple Quantum Dye units, then conjugated to an antibody, and finally released from the bead by specific cleavage with Proteinase K unedr physiological conditions. Since the luminescence of lanthanide(III) macrocycles is enhanced by the presence of GD(III) or Y(III) ions in a micellar system, a significant increase in signal can be achieved by attaching a polymer labeled with multiple Quantum Dye units to an analyte- binding species, such as a monoclonal antibody, or by taking advantage of the luminescence enhancing effects of Gd(III) or Y(III), or by both approaches concomitantly. A comparison between the integrated intensity and lifetime measurements of the Eu(III)-macrocycle under a variety of conditions show that the signal increase caused by Gd(III) can not be explained solely by the increase in lifetime, and must result in significant part from an energy transfer process invloving donors not directly bound to the Eu(III).

  14. Lanthanide complexes derived from hexadentate macrocyclic ligand: Synthesis, spectroscopic and thermal investigation

    NASA Astrophysics Data System (ADS)

    Chandra, Sulekh; Tyagi, Monika; Rani, Soni; Kumar, Sumit

    2010-02-01

    The lanthanide complexes derived from (3,5,13,15-tetramethyl 2,6,12,16,21-22-hexaazatricyclo[15.3.I 1-17I 7-11]cosa-1(21),2,5,7,9,11(22),12,15,17,19-decane) were synthesized. The complexes were found to have general composition [Ln(L)X 2·H 2O]X, where Ln = La 3+, Ce 3+, Nd 3+, Sm 3+ and Eu 3+ and X = NO 3- and Cl -. The ligand was characterized by elemental analyses, IR, Mass, and 1H NMR spectral studies. All the complexes were characterized by elemental analyses, molar conductance measurements, magnetic susceptibility measurements, IR, Mass, electronic spectral techniques and thermal studies. The ligand acts as a hexadentate and coordinates through four nitrogen atoms of azomethine groups and two nitrogen of pyridine ring. The lanthanum complexes are diamagnetic while the other Ln(III) complexes are paramagnetic. The spectral parameters i.e. nephelauxetic ratio ( β), covalency factor ( b1/2), Sinha parameter ( δ%) and covalency angular overlap parameter ( η) have been calculated from absorption spectra of Nd(III) and Sm(III) complexes. These parameters suggest the metal-ligand covalent bonding. In the present study, the complexes were found to have coordination number nine.

  15. Syntheses, crystal structures, magnetic and luminescence properties of five novel lanthanide complexes of nitronyl nitroxide radical

    SciTech Connect

    Wang, Ya-Li; Gao, Yuan-Yuan; Ma, Yue; Wang, Qing-Lun; Li, Li-Cun; Liao, Dai-Zheng

    2013-06-01

    Five novel Ln(III) complexes based on a new nitronyl nitroxide radical have been synthesized, characterized structurally and magnetically: [Ln(hfac)₃(NITPh-3-Br-4-OMe)₂] (Ln(III)=Eu(1), Gd(2), Tb(3), Dy(4), Ho(5); hfac=hexafluoroacetylacetonate; and NITPh-3-Br-4-OMe=2-3´-Br-4´-methoxyphenyl-4,4,5,5 -tetramethylimidazoline-1-oxyl-3-oxide). The single-crystal structures analyses show that these complexes have similar mononuclear tri-spin structures, in which central Ln(III) ions are all eight coordinated by three hfac molecules and two NITPh-3-Br-4-OMe radicals. The variable-temperature magnetic susceptibility studies reveal the antiferromagnetic interactions between the paramagnetic ions (Ln(III) and radicals) in complexes 1, 2, 3 and 5 and ferromagnetic interaction in complex 4. The luminescence characterizations of complexes Eu(1), Tb(3) and Dy(4) are also studied in this paper. - Graphical abstract: Using a novel halogen phenyl-substituted nitronyl-nitroxide radical, we obtained and characterized five isostructural lanthanide mononuclear tri-spin compounds. Highlights: • A new halogen phenyl-substituted nitronyl-nitroxide radical was designed. • Five new Ln(III) radical complexes have been synthesized and characterized. • The reasonable evaluation the magnetic interactions between Ln(III) ions and radical is meaningful. • These complexes show good luminescent properties.

  16. Thermodynamic, spectroscopic, and computational studies of lanthanide complexation with Diethylenetriaminepentaacetic acide: temperature effect and coordination modes

    SciTech Connect

    Guoxin Tian; Leigh R. Martin; Zhiyong Zhang; Linfeng Rao

    2011-04-01

    Stability constants of two DTPA (diethylenetriaminepentaacetic acid) complexes with lanthanides (ML2- and MHL-, where M stands for Nd and Eu and L stands for diethylenetriaminepentaacetate) at 10, 25, 40, 55, and 70 degrees C were determined by potentiometry, absorption spectrophotometry, and luminescence spectroscopy. The enthalpies of complexation at 25 degrees C were determined by microcalorimetry. Thermodynamic data show that the complexation of Nd3þ and Eu3þ with DTPA is weakened at higher temperatures, a 10-fold decrease in the stability constants of ML2- and MHL- as the temperature is increased from 10 to 70 degrees C. The effect of temperature is consistent with the exothermic enthalpy of complexation directly measured by microcalorimetry. Results by luminescence spectroscopy and density functional theory (DFT) calculations suggest that DTPA is octa-dentate in both the EuL2- and EuHL- complexes and, for the first time, the coordination mode in the EuHL- complex was clarified by integration of the experimental data and DFT calculations. In the EuHL- complex, the Eu is coordinated by an octa-dentate H(DTPA) ligand and a water molecule, and the protonation occurs on the oxygen of a carboxylate group.

  17. DISTRIBUTION OF LANTHANIDE AND ACTINIDE ELEMENTS BETWEEN BIS-(2-ETHYLHEXYL)PHOSPHORIC ACID AND BUFFERED LACTATE SOLUTIONS CONTAINING SELECTED COMPLEXANTS

    SciTech Connect

    Rudisill, Tracy S.; Diprete, David P.; Thompson, Major C.

    2013-04-15

    With the renewed interest in the closure of the nuclear fuel cycle, the TALSPEAK process is being considered for the separation of Am and Cm from the lanthanide fission products in a next generation reprocessing plant. However, an efficient separation requires tight control of the pH which likely will be difficult to achieve on a large scale. To address this issue, we measured the distribution of lanthanide and actinide elements between aqueous and organic phases in the presence of complexants which were potentially less sensitive to pH control than the diethylenetriaminepentaacetic (DTPA) used in the process. To perform the extractions, a rapid and accurate method was developed for measuring distribution coefficients based on the preparation of lanthanide tracers in the Savannah River National Laboratory neutron activation analysis facility. The complexants tested included aceto-, benzo-, and salicylhydroxamic acids, N,N,N',N'-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), and ammonium thiocyanate (NH{sub 4}SCN). The hydroxamic acids were the least effective of the complexants tested. The separation factors for TPEN and NH{sub 4}SCN were higher, especially for the heaviest lanthanides in the series; however, no conditions were identified which resulted in separations factors which consistently approached those measured for the use of DTPA.

  18. H4octapa: highly stable complexation of lanthanide(III) ions and copper(II).

    PubMed

    Kálmán, Ferenc Krisztián; Végh, Andrea; Regueiro-Figueroa, Martín; Tóth, Éva; Platas-Iglesias, Carlos; Tircsó, Gyula

    2015-03-01

    The acyclic ligand octapa(4-) (H4octapa = 6,6'-((ethane-1,2-diylbis((carboxymethyl)azanediyl))bis(methylene))dipicolinic acid) forms stable complexes with the Ln(3+) ions in aqueous solution. The stability constants determined for the complexes with La(3+), Gd(3+), and Lu(3+) using relaxometric methods are log KLaL = 20.13(7), log KGdL = 20.23(4), and log KLuL = 20.49(5) (I = 0.15 M NaCl). High stability constants were also determined for the complexes formed with divalent metal ions such as Zn(2+) and Cu(2+) (log KZnL = 18.91(3) and log KCuL = 22.08(2)). UV-visible and NMR spectroscopic studies and density functional theory (DFT) calculations point to hexadentate binding of the ligand to Zn(2+) and Cu(2+), the donor atoms of the acetate groups of the ligand remaining uncoordinated. The complexes formed with the Ln(3+) ions are nine-coordinated thanks to the octadentate binding of the ligand and the presence of a coordinated water molecule. The stability constants of the complexes formed with the Ln(3+) ions do not change significantly across the lanthanide series. A DFT investigation shows that this is the result of a subtle balance between the increased binding energies across the 4f period, which contribute to an increasing complex stability, and the parallel increase of the absolute values of the hydration free energies of the Ln(3+) ions. In the case of the [Ln(octapa)(H2O)](-) complexes the interaction between the amine nitrogen atoms of the ligand and the Ln(3+) ions is weakened along the lanthanide series, and therefore the increased electrostatic interaction does not overcome the increasing hydration energies. A detailed kinetic study of the dissociation of the [Gd(octapa)(H2O)](-) complex in the presence of Cu(2+) shows that the metal-assisted pathway is the main responsible for complex dissociation at pH 7.4 and physiological [Cu(2+)] concentration (1 μM).

  19. Ultrasoft pseudopotentials for lanthanide solvation complexes: core or valence character of the 4f electrons.

    PubMed

    Pollet, Rodolphe; Clavaguéra, Carine; Dognon, Jean-Pierre

    2006-04-28

    The 4f electrons of lanthanides, because of their strong localization in the region around the nucleus, are traditionally included in a pseudopotential core. This approximation is scrutinized by optimizing the structures and calculating the interaction energies of Gd(3+)(H(2)O) and Gd(3+)(NH(3)) microsolvation complexes within plane wave Perdew-Burke-Ernzerhof calculations using ultrasoft pseudopotentials where the 4f electrons are included either in the core or in the valence space. Upon comparison to quantum chemical MP2 and CCSD(T) reference calculations it is found that the explicit treatment of the 4f electrons in the valence shell yields quite accurate results including the required small spin polarization due to ligand charge transfer with only modest computational overhead.

  20. Making sense of lanthanide luminescence.

    PubMed

    Werts, Martinus H V

    2005-01-01

    The luminescence of trivalent lanthanide ions has found applications in lighting, lasers, optical telecommunications, medical diagnostics, and various other fields. This introductory review presents the basics of organic and inorganic luminescent materials containing lanthanide ions, their applications, and some recent developments. After a brief history of the discovery, purification and early spectroscopic studies of the lanthanides, the radiative and nonradiative transitions of the 4f electrons in lanthanide ions are discussed. Lanthanide-doped phosphors, glasses and crystals as well as luminescent lanthanide complexes with organic ligands receive attention with respect to their preparation and their applications. Finally, two recent developments in the field of luminescent materials are addressed: near-infrared luminescent lanthanide complexes and lanthanide-doped nano-particles.

  1. Versatile lanthanide-azide complexes with azide/carboxylate/hydroxy mixed bridged chain exhibiting magnetic and luminescent properties

    SciTech Connect

    Wang Haichao; Xue Min; Guo Qian; Zhao Jiongpeng; Liu Fuchen; Ribas, Joan

    2012-03-15

    Two new lanthanide-azide complexes, [Ln{sub 2}(N{sub 3})(isonic){sub 2}(OH){sub 3}(Hisonic)(H{sub 2}O)]{sub n} (Ln=Yb for 1 and Tb for 2, isonic=isonicotinate), were obtained in hydrothermal condition. X-ray diffraction analysis indicated the two complexes are isomorphic chain structure in which the Ln{sup III} ions are mixed bridged by the azide anions, hydroxyl anions and carboxylate groups of the isonicotinate ligands. Further studies indicated weak antiferromagnetic interactions between the Ln{sup III} ions in 1 and 2, and complex 2 exhibit green sensitized Luminescent character of Tb{sup III} ion. - Graphical abstract: Two new 1D lanthanide-azide complexes, [Ln{sub 2}(N{sub 3})(isonic){sub 2}(OH){sub 3}(Hisonic)(H{sub 2}O)]{sub n} (Ln=Yb{sup III} for 1 and Tb{sup III} for 2, isonic=isonicotinate), were synthesized by hydrothermal reaction and exhibit interesting magnetism and fluorescence properties. Highlights: Black-Right-Pointing-Pointer The research provided a new method for synthesizing lanthanide-azide complexes. Black-Right-Pointing-Pointer The complexes have an interesting azide/hydroxyl/carboxylate mixed bridged1D chain structure. Black-Right-Pointing-Pointer The antiferromagnetic coupling between the complexes and 2 displays green luminescence.

  2. Anion Effects on Lanthanide(III) Tetrazole-1-acetate Dinuclear Complexes Showing Slow Magnetic Relaxation and Photofluorescent Emission.

    PubMed

    Lu, Ying-Bing; Jiang, Xiao-Ming; Zhu, Shui-Dong; Du, Zi-Yi; Liu, Cai-Ming; Xie, Yong-Rong; Liu, Liang-Xian

    2016-04-18

    Three types of lanthanide complexes based on the tetrazole-1-acetic acid ligand and the 2,2'-bipyridine coligand were prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, and elemental analyses; the formulas of these complexes are [Ln2(1-tza)4(NO3)2(2,2'-bipy)2] (Ln = Sm (1), Eu (2), Gd (3), Tb (4), Dy (5)), [Dy2(1-tza)4Cl2(2,2'-bipy)2] (6), and [Yb2(1-tza)4(NO3)2(2,2'-bipy)2] (7) (1-tza = tetrazole-1-acetate and 2,2'-bipy = 2,2'-bipyridine). They are dinuclear complexes possessing similar structures but different lanthanide(III) ion coordination geometries because of the distinction of peripheral anions (such as NO3(-) and Cl(-)) and the effect of lanthanide contraction. The variable-temperature magnetic susceptibilities of 1-6 were measured. Both Dy(III) complexes (5 and 6) display field-induced single-molecule magnet behaviors. Ab initio calculations revealed that the Dy(III) complex 6 possesses a more anisotropic Dy(III) ion in comparison to that in 5. The room-temperature photoluminescence spectra of Sm(III) (1), Eu(III) (2), Tb(III) (4), and Dy(III) (5 and 6) complexes exhibit strong characteristic emissions in the visible region, whereas the Yb(III) (7) complex shows near-infrared (NIR) luminescence. PMID:27023680

  3. Thermodynamic and structural description of europium complexation in 1-octanol solution

    SciTech Connect

    Charbonnel, M.C.; Vu, T.H.; Boubals, N.; Couston, L.

    2008-07-01

    Polydentate N-bearing ligands such as bis-triazinyl-pyridines (BTPS) are interesting extractants for actinide(III)/lanthanide(III) separation. A description of europium complexation in 1-octanol solutions was undertaken to enhance the knowledge of the extraction mechanisms. Time- Resolved Laser-Induced Fluorescence (TRLIF) spectroscopy allows determination of the first solvation shell for europium(III) nitrate, chloride, and perchlorate with different amounts of water. Europium nitrate complexation by iPr-BTP was then studied by TRLIF and microcalorimetry; the stability constant related to the formation of Eu(BTP){sub 3}{sup 3+} is similar by both techniques (log {beta}{sub 3} = 11.3 {+-} 0.5). The difference of solvation of the cation seems to have an influence on the thermodynamic properties related to the complexation with organic ligands. (authors)

  4. Near-IR luminescent lanthanide complexes with 1,8-diaminoanthraquinone-based chromophoric ligands.

    PubMed

    Stacey, Oliver J; Ward, Benjamin D; Amoroso, Angelo J; Pope, Simon J A

    2016-04-21

    Three new chromophoric anthraquinone-based multidentate ligands have been synthesised in a step-wise manner from 1,8-dichloroanthraquinone. The ligands each comprise two dipicolyl amine units and react with trivalent lanthanide ions to form monometallic complexes of the form [Ln(L)](OTf)3 as indicated by MS studies and elemental analyses. Supporting DFT studies show that the monometallic species are highly favoured (>1000 kJ mol(-1)) over the formation of a 2 : 2 dimetallic congener. Both ligands and complexes absorb light efficiently (ε ∼ 10(4) M(-1) cm(-1)) in the visible part of the spectrum, with λabsca. 535-550 nm through an intramolecular charge transfer (ICT) transition localised on the substituted anthraquinone unit. In all cases the complexes show a fluorescence band at ca. 675 nm due to the ICT emitting state. The corresponding Nd(iii), Yb(iii) and Er(iii) complexes also reveal sensitised near-IR emission characteristic of each ion following excitation of the ICT visible absorption band at 535 nm. PMID:26974664

  5. Tuning a Lanthanide Complex To Be Responsive to the Environment in Solution.

    PubMed

    Golkowski, Ryan T; Settineri, Nicholas S; Zhao, Xikang; McMillin, David R

    2015-12-01

    The f-f emissions of lanthanide-ion complexes have predictable emission energies and many practical applications, but the emitting states are generally impervious to the surroundings. This investigation explores ligand- and metal-centered emission processes for a series of mixed-ligand complexes of composition M(X-T)(NO3)3, where the metal ion is europium, gadolinium, terbium, or lutetium, and X-T denotes the tridentate ligand 2,2':6',2″-terpyridine (H-T), 4'-phenyl-2,2':6',2″-terpyridine (Ph-T), or 4'-pyrrolidin-N-yl-2,2':6',2″-terpyridine (pyrr-T). The presence of the pyrrolidinyl substituent imparts intraligand charge-transfer (ILCT) character to the ligand-based excited states and reduces the energy gap between the singlet and the triplet excited states. An enhanced rate of intersystem crossing results in a lutetium complex with a relatively small fluorescence quantum yield (0.15%) and a gadolinium complex with an impressive phosphorescence yield of 9.6% in deaerated solution. The Tb(pyrr-T)(NO3)3 system is unique because the relatively low-energy triplet ILCT state equilibrates with the emissive f-f state. The result is a truly remarkable f-f emission signal that is sensitive to the polarity of the local environment as well as the presence of dioxygen. PMID:26571330

  6. Spectroscopic, luminescence, electrochemical and antimicrobial studies of lanthanide complexes of bis-benzimidazole derived ligands

    NASA Astrophysics Data System (ADS)

    Siddiqi, Zafar A.; Shahid, Anjuli M.; Khalid, Mohd.; Sharma, Prashant K.; Siddique, Armeen

    2013-04-01

    The lanthanide complexes of [1,2-bis(benzimidazole-2-yl)ethane dihydrochloride], L1·2HCl and [1,4-bis(benzimidazole-2-onium)butane dihydrochloride], L2·2HCl having molecular formulae [Ln(L1)2Cl3H2O] and [Ln(L2)2Cl3H2O]·2H2O (Ln = La3+, Pr3+, Nd3+ and Gd3+), respectively, were prepared and characterized through IR, 1H and 13C NMR, ESI-mass, UV-visible and luminescence spectroscopic techniques. TGA data suggested presence of the coordinated and the lattice water. The oscillator strengths of the f-f transitions and the covalency parameters (β, b1/2 and δ) have been evaluated from the electronic spectral data. The proposed octa coordinate geometry for the complexes has been ascertained from the molecular model computations. CV studies indicate formation of stable quasi-reversible redox couples PrIII/IV, Nd III/IV and GdIII/IV in solution. The in vitro antimicrobial activities of the complexes have been evaluated against gram +ve and gram -ve bacteria and fungi.

  7. Lipophilic ternary complexes in liquid-liquid extraction of trivalent lanthanides

    SciTech Connect

    Lumetta, Gregg J.; Levitskaia, Tatiana G.; Latesky, Stanley; Henderson, Renesha V.; Edwards, Emilio A.; Braley, Jenifer C.; Sinkov, Sergey I.

    2012-03-01

    The formation of ternary complexes between lanthanide ions [Nd(III) or Eu(III)], octyl(phenyl)-N,N-diisobutyl-carbamoylmethylphosphine oxide (CMPO), and bis-(2-ethylhexyl)phosphoric acid (HDEHP) was probed by liquid-liquid extraction and spectroscopic techniques. Equilibrium modeling of data for the extraction of Nd(III) or Eu(III) from lactic acid media into n-dodecane solutions of CMPO and HDEHP indicates the predominant extracted species are of the type [Ln(AHA){sub 2}(A)] and [Ln(CMPO)(AHA){sub 2}(A)], where Ln = Nd or Eu and A represents the DEHP{sup -} anion. FTIR (for both Eu and Nd) and visible spectrophotometry (in the case of Nd) indicate the formation of the [Ln(CMPO)(A){sup 3}] complexes when CMPO is added to n-dodecane solutions of the LnA{sub 3} compounds. Both techniques indicate a stronger propensity of CMPO to complex Nd(III) versus Eu(III).

  8. Lanthanide-to-lanthanide energy-transfer processes operating in discrete polynuclear complexes: can trivalent europium be used as a local structural probe?

    PubMed

    Zaïm, Amir; Eliseeva, Svetlana V; Guénée, Laure; Nozary, Homayoun; Petoud, Stéphane; Piguet, Claude

    2014-09-15

    This work, based on the synthesis and analysis of chemical compounds, describes a kinetic approach for identifying intramolecular intermetallic energy-transfer processes operating in discrete polynuclear lanthanide complexes, with a special emphasis on europium-containing entities. When all coordination sites are identical in a (supra)molecular complex, only heterometallic communications are experimentally accessible and a Tb → Eu energy transfer could be evidenced in [TbEu(L5)(hfac)6] (hfac = hexafluoroacetylacetonate), in which the intermetallic separation amounts to 12.6 Å. In the presence of different coordination sites, as found in the trinuclear complex [Eu3(L2)(hfac)9], homometallic communication can be induced by selective laser excitation and monitored with the help of high-resolution emission spectroscopy. The narrow and non-degenerated character of the Eu((5)D0 ↔ (7)F0) transition excludes significant spectral overlap between donor and acceptor europium cations. Intramolecular energy-transfer processes in discrete polynuclear europium complexes are therefore limited to short distances, in agreement with the Fermi golden rule and with the kinetic data collected for [Eu3(L2)(hfac)9] in the solid state and in solution. Consequently, trivalent europium can be considered as a valuable local structural probe in discrete polynuclear complexes displaying intermetallic separation in the sub-nanometric domain, a useful property for probing lanthanido-polymers.

  9. Nanoparticles speckled by ready-to-conjugate lanthanide complexes for multimodal imaging

    NASA Astrophysics Data System (ADS)

    Biju, Vasudevanpillai; Hamada, Morihiko; Ono, Kenji; Sugino, Sakiko; Ohnishi, Takashi; Shibu, Edakkattuparambil Sidharth; Yamamura, Shohei; Sawada, Makoto; Nakanishi, Shunsuke; Shigeri, Yasushi; Wakida, Shin-Ichi

    2015-09-01

    Multimodal and multifunctional contrast agents receive enormous attention in the biomedical imaging field. Such contrast agents are routinely prepared by the incorporation of organic molecules and inorganic nanoparticles (NPs) into host materials such as gold NPs, silica NPs, polymer NPs, and liposomes. Despite their non-cytotoxic nature, the large size of these NPs limits the in vivo distribution and clearance and inflames complex pharmacokinetics, which hinder the regulatory approval for clinical applications. Herein, we report a unique method that combines magnetic resonance imaging (MRI) and fluorescence imaging modalities together in nanoscale entities by the simple, direct and stable conjugation of novel biotinylated coordination complexes of gadolinium(iii) to CdSe/ZnS quantum dots (QD) and terbium(iii) to super paramagnetic iron oxide NPs (SPION) but without any host material. Subsequently, we evaluate the potentials of such lanthanide-speckled fluorescent-magnetic NPs for bioimaging at single-molecule, cell and in vivo levels. The simple preparation and small size make such fluorescent-magnetic NPs promising contrast agents for biomedical imaging.

  10. Highly Luminescent Salts Containing Well-Shielded Lanthanide-Centered Complex Anions and Bulky Imidazolium Countercations

    SciTech Connect

    Tang, Si-Fu; Lorbeer, Chantal; Wang, Xinjiao; Ghosh, Pushpal; Mudring, Anja-Verena

    2014-09-02

    Four salts containing imidazolium cations and europium(III)- or terbium(III)-centered complex anions have been successfully synthesized from an ethanol/H2O solution. The single-crystal X-ray diffraction analyses reveal that these compounds have a common formula of [R][Ln(DETCAP)4] [R = 1-ethyl-3-methylimidazolium (C2mim), Ln = Eu (1) and Tb (2); R = 1-butyl-3-methylimidazolium (C4mim), Ln = Eu (3) and Tb (4); DETCAP = diethyl-2,2,2-trichloroacetylphosphoramidate], in which the lanthanide centers are chelated by four chelating pseudo-β-diketonate ligands (DETCAP)-, forming the respective complex anions. Their thermal behaviors and stabilities were also investigated to study the role of the length of the side chain in the cations. Fluorescence measurements at both room temperature and liquid-nitrogen temperature show that these materials show intense characteristic europium(III) or terbium(III) emissions and have long decay times. Their overall quantum yields were determined to be in the range of 30–49%.

  11. Lanthanide and transition metal complexes of bioactive coumarins: molecular modeling and spectroscopic studies.

    PubMed

    Georgieva, I; Mihaylov, Tz; Trendafilova, N

    2014-06-01

    The present paper summarizes theoretical and spectroscopic investigations on a series of active coumarins and their lanthanide and transition metal complexes with application in medicine and pharmacy. Molecular modeling as well as IR, Raman, NMR and electronic spectral simulations at different levels of theory were performed to obtain important molecular descriptors: total energy, formation energy, binding energy, stability, conformations, structural parameters, electron density distribution, molecular electrostatic potential, Fukui functions, atomic charges, and reactive indexes. The computations are performed both in gas phase and in solution with consideration of the solvent effect on the molecular structural and energetic parameters. The investigations have shown that the advanced computational methods are reliable for prediction of the metal-coumarin binding mode, electron density distribution, thermodynamic properties as well as the strength and nature of the metal-coumarin interaction (not experimentally accessible) and correctly interpret the experimental spectroscopic data. Known results from biological tests for cytotoxic, antimicrobial, anti-fungal, spasmolytic and anti-HIV activities on the studied metal complexes are reported and discussed. PMID:24680836

  12. Self-assembly of 2-aldehyde-8-hydroxyquinolinate-based lanthanide complexes and NIR luminescence

    NASA Astrophysics Data System (ADS)

    Zhang, Meiqi; Li, Hongfeng; Chen, Peng; Sun, Wenbin; Zhang, Lei; Yan, Pengfei

    2015-02-01

    Self-assembly reaction of 2-aldehyde-8-hydroxyquinoline, tris(hydroxymethyl)aminomethane and LnCl3ṡ6H2O affords a series of mononuclear lanthanide complexes Ce(baho)2·Et2O (1) (H2baho = 2,8-bis(2-(8-hydroxylquinolinyl))-1-aza-5-hydroxymethyl-3,7-dioxabicyclo[3.3.0]octane), Dy(nhm)2Cl·0.5H2O (2) and Ln(nhm)2Cl·0.5C6H14 (Ln = Ho (3), Er (4), Yb (5) and Hnhm = N-(2-(8-hydroxylquinolinyl)methylene)(trishydroxymethyl)methylamine. The crystal structures have been determined by X-ray crystallographic analysis, and the tetravalence of Ce in 1 has been proven by XPS. Interestingly, the positive charge of Ce4+ ion in 1 is neutralized by two deprotonated baho2- ligands, while two deprotonated nhm- ligands and one Cl- compensate the positive charge of Ln3+ ions in 2-5. Complex 5 exhibit essential NIR luminescence of Yb3+ ion with lifetime of 17.64 μs in solid and 9.96 μs in CH3OH solution.

  13. Synthesis and evaluation of lanthanide ion DOTA-tetraamide complexes bearing peripheral hydroxyl groups

    PubMed Central

    Pasha, Azhar; Lin, Mai; Tircsó, Gyula; Rostollan, Cynthia L.; Woods, Mark; Kiefer, Garry E.; Sherry, A. Dean; Sun, Xiankai

    2009-01-01

    The use of lanthanide-based contrast agents for magnetic resonance imaging (MRI) has become an integral component of this important diagnostic modality. These inert chelates typically possess high thermodynamic stability constants that serve as a predictor for in vivo stability and low toxicity. Recently a new class of contrast agents was reported having a significantly lower degree thermodynamic stability while exhibiting biodistribution profiles indicative of high stability under biological conditions. These observations are suggestive that the nature of contrast agent stability is also dependent upon the kinetics of complex dissociation; a feature of potential importance when contemplating the design of new chelates for in vivo use. In this paper we present a study of the kinetics of acid catalyzed dissociation, thermodynamic stability, serum stability and biodistribution of a series of DOTA-tetraamide complexes that have been substituted with peripheral hydroxyl groups. The data indicate that these non-traditional contrast agents exhibit in vivo stability comparable to agents with much higher log KML values demonstrating the important contribution of kinetic inertness. PMID:19083028

  14. In vitro imaging and human serum albumin responsive dimeric lanthanide DO3A complex.

    PubMed

    Fung, Yuen On; Wu, Wanqing; Yeung, Chi-Tung; Kong, Hoi-Kuan; Wong, Kenny Kam-Cheng; Lo, Wai-Sum; Law, Ga-Lai; Wong, Ka-Leung; Lau, Chi-Kong; Lee, Chi-Sing; Wong, Wing-Tak

    2011-06-20

    Two series of dimeric DO3A (1,4,7,10-tetraazacyclodecane-1,4,7-triacetate) lanthanide complexes (LnL(1)-LnL(2), Ln = Eu, Gd, and Tb) have been synthesized with two different bridged chromophores. The X-ray structures of dimeric LnL(1) (Ln = Gd and Tb) complexes show that each metal ion has nine coordination numbers with eight directly bound donor atoms of the ligand and one oxygen donor from the water molecule. Photophysical measurements indicate that the bridged antenna in LnL(2) gives a higher efficiency than that of LnL(1) and is responsive to the protein Human Serum Albumin (HSA), giving an f-f luminescence signal enhancement with a binding constant log K = 4.84. In vitro imaging of EuL(1) and EuL(2) in HeLa cells has been recorded, and EuL(2) has demonstrated a higher rate of cellular uptake and low cytotoxicity (IC(50) = 3 mM).

  15. Cyanomethylene-bis(phosphonate)-based lanthanide complexes: structural, photophysical, and magnetic investigations.

    PubMed

    Maxim, Catalin; Branzea, Diana G; Tiseanu, Carmen; Rouzières, Mathieu; Clérac, Rodolphe; Andruh, Marius; Avarvari, Narcis

    2014-03-01

    The syntheses, structural investigations, magnetic and photophysical properties of a series of 10 lanthanide mononuclear complexes, containing the heteroditopic ligand cyanomethylene-bis(5,5-dimethyl-2-oxo-1,3,2λ(5)-dioxa-phosphorinane) (L), are described. The crystallographic analyses indicate two structural types: in the first one, [Ln(III)(L)3(H2O)2]·H2O (Ln = La, Pr, Nd), the metal ions are eight-coordinated within a square antiprism geometry, while the second one, [Ln(III)(L)3(H2O)]·8H2O (Ln = Sm, Eu, Gd, Tb, Dy, Ho, Er), contains seven-coordinated Ln(III) ions within distorted monocapped trigonal prisms. Intermolecular hydrogen bonding between nitrogen atoms of the cyano groups, crystallization, and coordination water molecules leads to the formation of extended supramolecular networks. Solid-state photophysical investigations demonstrate that Eu(III) and Tb(III) complexes possess intense luminescence with relatively long excited-state lifetimes of 530 and 1370 μs, respectively, while Pr(III), Dy(III), and Ho(III) complexes have weak intensity luminescence characterized by short lifetimes ranging between a few nanoseconds to microseconds. The magnetic properties for Pr(III), Gd(III), Tb(III), Dy(III), and Ho(III) complexes are in agreement with isolated Ln(III) ions in the solid state, as suggested by the single-crystal X-ray analyses. Alternating current (ac) susceptibility measurements up to 10 kHz reveal that only the Ho(III) complex shows a frequency-dependent ac response, with a relaxation mode clearly observed at 1.85 K around 4500 Hz.

  16. The Lanthanide Contraction Revisited

    SciTech Connect

    Seitz, Michael; Oliver, Allen G.; Raymond, Kenneth N.

    2007-04-19

    A complete, isostructural series of lanthanide complexes (except Pm) with the ligand TREN-1,2-HOIQO has been synthesized and structurally characterized by means of single-crystal X-ray analysis. All complexes are 1D-polymeric species in the solid state, with the lanthanide being in an eight-coordinate, distorted trigonal-dodecahedral environment with a donor set of eight unique oxygen atoms. This series constitutes the first complete set of isostructural lanthanide complexes with a ligand of denticity greater than two. The geometric arrangement of the chelating moieties slightly deviates across the lanthanide series, as analyzed by a shape parameter metric based on the comparison of the dihedral angles along all edges of the coordination polyhedron. The apparent lanthanide contraction in the individual Ln-O bond lengths deviates considerably from the expected quadratic decrease that was found previously in a number of complexes with ligands of low denticity. The sum of all bond lengths around the trivalent metal cation, however, is more regular, showing an almost ideal quadratic behavior across the entire series. The quadratic nature of the lanthanide contraction is derived theoretically from Slater's model for the calculation of ionic radii. In addition, the sum of all distances along the edges of the coordination polyhedron show exactly the same quadratic dependency as the Ln-X bond lengths. The universal validity of this coordination sphere contraction, concomitant with the quadratic decrease in Ln-X bond lengths, was confirmed by reexamination of four other, previously published, almost complete series of lanthanide complexes. Due to the importance of multidentate ligands for the chelation of rare-earth metals, this result provides a significant advance for the prediction and rationalization of the geometric features of the corresponding lanthanide complexes, with great potential impact for all aspects of lanthanide coordination.

  17. Aromatic Lateral Substituents Influence the Excitation Energies of Hexaaza Lanthanide Macrocyclic Complexes: A Wave Function Theory and Density Functional Study.

    PubMed

    Rabanal-León, Walter A; Murillo-López, Juliana A; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro

    2015-09-24

    The high interest in lanthanide chemistry, and particularly in their luminescence, has been encouraged by the need of understanding the lanthanide chemical coordination and how the design of new luminescent materials can be affected by this. This work is focused on the understanding of the electronic structure, bonding nature, and optical properties of a set of lanthanide hexaaza macrocyclic complexes, which can lead to potential optical applications. Here we found that the DFT ground state of the open-shell complexes are mainly characterized by the manifold of low lying f states, having small HOMO-LUMO energy gaps. The results obtained from the wave function theory calculations (SO-RASSI) put on evidence the multiconfigurational character of their ground state and it is observed that the large spin-orbit coupling and the weak crystal field produce a strong mix of the ground and the excited states. The electron localization function (ELF) and the energy decomposition analysis (EDA) support the idea of a dative interaction between the macrocyclic ligand and the lanthanide center for all the studied systems; noting that, this interaction has a covalent character, where the d-orbital participation is evidenced from NBO analysis, leaving the f shell completely noninteracting in the chemical bonding. From the optical part we observed in all cases the characteristic intraligand (IL) (π-π*) and ligand to metal charge-transfer (LMCT) bands that are present in the ultraviolet and visible regions, and for the open-shell complexes we found the inherent f-f electronic transitions on the visible and near-infrared region. PMID:26325624

  18. The Preparation, Characterization, and Magnetism of Copper 15-Metallacrown-5 Lanthanide Complexes.

    PubMed

    Stemmler, Ann J.; Kampf, Jeff W.; Kirk, Martin L.; Atasi, Bassel H.; Pecoraro, Vincent L.

    1999-06-14

    The preparation and characterization of a series of encapsulated-lanthanide 15-metallacrown-5 complexes are reported. Planar ligands such as picoline hydroxamic acid (picha) or nonplanar alpha-amino hydroxamic acids (e.g., glycine hydroxamic acid (glyha)) led to one-step syntheses of metallacrowns in yields as high as 85%. The reaction of the appropriate hydroxamic acid with copper acetate and (1)/(5) equiv of gadolinium(III) or europium(III) nitrates in DMF or water yielded crystals of Gd(NO(3))(3)[15-MC(Cu(II)N(picha))-5], 1, Eu(NO(3))(3)[15-MC(Cu(II)N(picha))-5], 2, and Eu(NO(3))(3)[15-MC(Cu(II)N(glyha))-5], 3. Several other 15-metallacrown-5 complexes were synthesized with (1) Cu(II) or Ni(II) in the metallacrown ring metal position, (2) various lanthanides (La(III), Nd(III), Sm(III), Eu(III), Gd(III), Dy(III), Ho(III), Er(III), and Yb(III)) encapsulated in the center of the ring, and (3) chiral alpha-amino hydroxamic acids (e.g., phenylalanine hydroxamic acid (H(2)pheha), leucine hydroxamic acid (H(2)leuha), and tyrosine hydroxamic acid (H(2)tyrha)). It is believed that all of the complexes containing Cu(II) ions have the ring metals either in four-coordinate, square-planar environments, bound to two tetradentate hydroximate ligands, or in five-coordinate, square-pyramidal geometries if solvent is bound. Spectroscopic and magnetic characterization of the Ni(II) complexes suggests that they are either five- or six-coordinate. The encapsulated lanthanides are generally pentagonal bipyramidal, with five oxygen donors from the metallacrown ring and solvent or bidentate nitrate ions in the axial positions. The circular arrangement of ions results in interesting magnetic behavior. With Dy(III) encapsulated in the center of the ring, a magnetic moment as high as 10.9 &mgr;(B) is achieved. Analysis of the variable-temperature susceptibility of La(NO(3))(3)[15-MC(Cu(II)N(picha))-5] indicates that the five Cu(II) ions are antiferromagnetically coupled, forming an S = (1

  19. Mechanistic insights into the luminescent sensing of organophosphorus chemical warfare agents and simulants using trivalent lanthanide complexes.

    PubMed

    Dennison, Genevieve H; Johnston, Martin R

    2015-04-20

    Organophosphorus chemical warfare agents (OP CWAs) are potent acetylcholinesterase inhibitors that can cause incapacitation and death within minutes of exposure, and furthermore are largely undetectable by the human senses. Fast, efficient, sensitive and selective detection of these compounds is therefore critical to minimise exposure. Traditional molecular-based sensing approaches have exploited the chemical reactivity of the OP CWAs, whereas more recently supramolecular-based approaches using non-covalent interactions have gained momentum. This is due, in part, to the potential development of sensors with second-generation properties, such as reversibility and multifunction capabilities. Supramolecular sensors also offer opportunities for incorporation of metal ions allowing for the exploitation of their unique properties. In particular, trivalent lanthanide ions are being increasingly used in the OP CWA sensing event and their use in supramolecular sensors is discussed in this Minireview. We focus on the fundamental interactions of simple lanthanide systems with OP CWAs and simulants, along with the development of more elaborate and complex systems including those containing nanotubes, polymers and gold nanoparticles. Whilst literature investigations into lanthanide-based OP CWA detection systems are relatively scarce, their unique and versatile properties provide a promising platform for the development of more efficient and complex sensing systems into the future.

  20. An europium(III) diglycolamide complex: insights into the coordination chemistry of lanthanides in solvent extraction.

    PubMed

    Antonio, Mark R; McAlister, Daniel R; Horwitz, E Philip

    2015-01-14

    The synthesis, stoichiometry, and structural characterization of a homoleptic, cationic europium(III) complex with three neutral tetraalkyldiglycolamide ligands are reported. The tri(bismuth tetrachloride)tris(N,N,N',N'-tetra-n-octyldiglycolamide)Eu salt, [Eu(TODGA)3][(BiCl4)3] obtained from methanol was examined by Eu L3-edge X-ray absorption spectroscopy (XAS) to reveal an inner-sphere coordination of Eu(3+) that arises from 9 O atoms and two next-nearest coordination spheres that arise from 6 carbon atoms each. A structural model is proposed in which each TODGA ligand with its O=Ca-Cb-O-Cb-Ca=O backbone acts as a tridentate O donor, where the two carbonyl O atoms and the one ether O atom bond to Eu(3+). Given the structural rigidity of the tridentate coordination motif in [Eu(TODGA)3](3+) with six 5-membered chelate rings, the six Eu-Ca and six Eu-Cb interactions are readily resolved in the EXAFS (extended X-ray absorption fine structure) spectrum. The three charge balancing [BiCl4](-) anions are beyond the cationic [Eu(TODGA)3](3+) cluster in an outer sphere environment that is too distant to be detected by XAS. Despite their sizeable length and propensity for entanglement, the four n-octyl groups of each TODGA (for a total of twelve) do not perturb the Eu(3+) coordination environment over that seen from previously reported single-crystal structures of tripositive lanthanide (Ln(3+)) complexes with tetraalkyldiglycolamide ligands (of the same 1:3 metal-to-ligand ratio stoichiometry) but having shorter i-propyl and i-butyl groups. The present results set the foundation for understanding advanced solvent extraction processes for the separation of the minor, tripositive actinides (Am, Cm) from the Ln(3+) ions in terms of the local structure of Eu(3+) in a solid state coordination complex with TODGA.

  1. Pentamethylcyclopentadienyl and bis(trimethylsilyl)amido complexes of the di- and trivalent lanthanides

    SciTech Connect

    Tilley, T.D.

    1982-03-01

    The reaction of the divalent iodides YbI/sub 2/ and EuI/sub 2/ with NaN(SiMe/sub 3/)/sub 2/ has provided pentane-soluble, monomeric derivatives of the divalent lanthanides. These compounds are isolated as the solvated species Eu(N(SiMe/sub 3/)/sub 2/)/sub 2/L/sub 2/ (L = thf or 1,2-dme), Yb(N(SiMe/sub 3/)/sub 2/)/sub 2/(thf)/sub 1/ /sub 5/ and Yb(N(SiMe/sub 3/)/sub 2/)/sub 2/L/sub 2/ (L = 1,2-dme or OEt/sub 2/), or as the sodium salts NaM(N(SiMe/sub 3/)/sub 2/)/sub 3/ (M = Eu or Yb). The pentamethylcyclopentadienyl ligand has been used to obtain trivalent derivatives of the type (C/sub 5/Me/sub 5/)/sub 2/MCl/sub 2/M'L/sub x/ (M = Nd, Sm or Yb; M' = Li or Na; L = OEt/sub 2/ or tmed) or (C/sub 5/Me/sub 5/)/sub 2/MCl(thf) (M = Nd or Yb). These compounds undergo metathesis reactions. The interaction of NaC/sub 5/Me/sub 5/ with EuCl/sub 3/ yields only the divalent (C/sub 5/Me/sub 5/)/sub 2/EuL (L = thf or OEt/sub 2/). Analogous compounds of ytterbium are obtained by reaction of YbI/sub 2/ with NaC/sub 5/Me/sub 5/ in thf or OEt/sub 2/. The ytterbium amine complexes are weakly paramagnetic, apparently due to charge transfer from ytterbium to the aromatic rings. The divalent phosphine complexes (C/sub 5/Me/sub 5/)/sub 2/ML (M = Eu or Yb; L = dmpe or dmpm) are also described. Crystallographic data are summarized.

  2. New crystal structural families of lanthanide chloride alcohol/water complexes

    SciTech Connect

    Chakoumakos, Bryan C; Custelcean, Radu; Ramey, Joanne Oxendine; Boatner, Lynn A

    2012-01-01

    The exploration of lanthanide chloride compounds as possible scintillation materials for gamma ray and neutron detection has led to the discovery of several new families of crystal structures with the general formula LnCl3(CH3OH)x(H2O)y. The specific crystal structure depends on the water/methanol content and lanthanide ion. The coordination of the light (large) lanthanides is the typical value of 8 and reduces to 7 for the heavier (small) lanthanides. The binding energy of water versus alcohol ligands is comparable, so that if water is present in the system, it is typically incorporated as a ligand in the crystal. In these crystals, the molecular adducts occur as monomers, dimers, and dichloro-bridged chains. These, in turn, form 3-D frameworks through H-bonds to the Cl atoms. Other distinct crystal structures are predicted, given the volume changes due to the lanthanide contraction, the water content of the crystal growth solutions, and the specific halide.

  3. A general method for preparing lanthanide oxide nanoparticles via thermal decomposition of lanthanide(III) complexes with 1-hydroxy-2-naphthoic acid and hydrazine ligands

    NASA Astrophysics Data System (ADS)

    Parimalagandhi, Karuppannan; Premkumar, Thathan; Vairam, Sundararajan

    2016-09-01

    Six new lanthanide(III) complexes (i.e., [Ln(L)2(NA)1.5]·3H2O, where Ln=La(III), Pr(III), Nd(III), Sm(III), Gd(III), and Ce(III) and L and NA indicate N2H4 and C10H6(1-O)(2-COO), respectively) with 1-hydroxy-2-naphthoic acid [C10H6(1-O)(2-COOH)] and hydrazine (N2H4) as co-ligands were characterized by elemental, FTIR, UV-visible, and XRD techniques. In the FT-IR spectra, the N-N stretching frequency in the range of 981-949 cm-1 demonstrates evidence of the presence of coordinated N2H4, indicating the bidentate bridging nature of hydrazine in the complexes. These complexes show symmetric and asymmetric COO- stretching from 1444 to 1441 cm-1 and 1582 to 1557 cm-1, respectively, indicating bidentate coordination. TG-DTA studies revealed that the compounds underwent endothermic dehydration from 98 to 110 °C. This was followed by the exothermic decomposition of oxalate intermediates to yield the respective metal oxides as the end products. From SEM images, the average size of the metal oxide particles prepared by thermal decomposition of the complexes was determined to be 39-42 nm. The powder X-ray and SEM coupled with energy dispersive X-ray (EDX) studies revealed the presence of the respective nano-sized metal oxides. The kinetic parameters of the decomposition of the complexes were calculated using the Coats-Redfern equation.

  4. Heterodimetallic [LnLn′] Lanthanide Complexes: Toward a Chemical Design of Two-Qubit Molecular Spin Quantum Gates

    PubMed Central

    2015-01-01

    A major challenge for realizing quantum computation is finding suitable systems to embody quantum bits (qubits) and quantum gates (qugates) in a robust and scalable architecture. An emerging bottom-up approach uses the electronic spins of lanthanides. Universal qugates may then be engineered by arranging in a molecule two interacting and different lanthanide ions. Preparing heterometallic lanthanide species is, however, extremely challenging. We have discovered a method to obtain [LnLn′] complexes with the appropriate requirements. Compound [CeEr] is deemed to represent an ideal situation. Both ions have a doubly degenerate magnetic ground state and can be addressed individually. Their isotopes have mainly zero nuclear spin, which enhances the electronic spin coherence. The analogues [Ce2], [Er2], [CeY], and [LaEr] have also been prepared to assist in showing that [CeEr] meets the qugate requirements, as revealed through magnetic susceptibility, specific heat, and EPR. Molecules could now be used for quantum information processing. PMID:25203521

  5. Trinuclear lanthanide complexes of a compartmental ligand N, N'-bis(2-pyridinyl)-2,6-pyridinedicarboxamide: A spectroscopic investigation

    NASA Astrophysics Data System (ADS)

    Gudasi, Kalagouda B.; Shenoy, Rashmi V.; Vadavi, Ramesh S.; Patil, Siddappa A.

    2006-11-01

    Trinuclear lanthanide complexes of the formula [Ln 3(PPDA)(NO 3) 6(H 2O) 2]·NO 3·2H 2O where Ln = La(III), Pr(III), Sm(III), Nd(III), Eu(III) Gd(III) Tb(III), Dy(III) and Y(III); H 2PPDA = N, N'-bis(2-pyridinyl)-2,6-pyridinedicarboxamide, have been isolated. The complexes were characterized by elemental analyses, conductivity measurements, magnetic susceptibility measurements and spectral (IR, NMR, UV-vis, fluorescence, FAB and EPR) and thermal studies.

  6. Core–shell Ag@SiO{sub 2} nanoparticles of different silica shell thicknesses: Preparation and their effects on photoluminescence of lanthanide complexes

    SciTech Connect

    Kang, Jie; Li, Yuan; Chen, Yingnan; Wang, Ailing; Yue, Bin; Qu, Yanrong; Zhao, Yongliang; Chu, Haibin

    2015-11-15

    Highlights: • Ag@SiO{sub 2} nanoparticles of different silica shell thicknesses were prepared via the Stöber process. • Sm and Dy complexes with benzoate, 1,10-phenanthroline and 2,2′-bipyridine were synthesized. • The complex-doped Ag@SiO{sub 2} composites show stronger luminescent intensities than pure complexes. • The luminescent intensities of the composites strongly depend on the SiO{sub 2} shell thickness. - Abstract: Three kinds of almost spherical core–shell Ag@SiO{sub 2} nanoparticles of different silica shell thicknesses (10, 25 and 80 nm) were prepared via the Stöber process. The Ag core nanoparticles were prepared by reducing silver nitrate with sodium citrate. The size, morphology and structure of core–shell Ag@SiO{sub 2} nanoparticles were characterized by transmission electron microscopy. Subsequently, eight kinds of lanthanide complexes with benzoate, 1,10-phenanthroline and 2,2′-bipyridine were synthesized. The composition of the lanthanide complexes was characterized by elemental analysis, IR and UV spectra. Finally, lanthanide complexes were attached to the surface of Ag@SiO{sub 2} nanoparticles to form lanthanide-complex-doped Ag@SiO{sub 2} nanocomposites. The results show that the complex-doped Ag@SiO{sub 2} nanocomposites display much stronger luminescence intensities than the lanthanide complexes. Furthermore, the luminescence intensities of the lanthanide-complex-doped Ag@SiO{sub 2} nanocomposites with SiO{sub 2} shell thickness of 25 nm are stronger than those of the nanocomposites with SiO{sub 2} shell thickness of 10 and 80 nm.

  7. Novel lanthanide(II) complexes supported by carbon-bridged biphenolate ligands: synthesis, structure and catalytic activity.

    PubMed

    Deng, Mingyu; Yao, Yingming; Shen, Qi; Zhang, Yong; Sun, Jin

    2004-03-21

    [Ln[N(SiMe3)2]2(THF)2](Ln = Sm, Yb) reacts with 1 equiv. of carbon-bridged biphenols, 2,2'-methylene-bis(6-tert-butyl-4-methylphenol)(L1H2) or 2,2'-ethylidene-bis(4,6-di-tert-butylphenol)(L2H2), in toluene to give the novel aryloxide lanthanide(II) complexes [[LnL1(THF)n]2](Ln = Sm, n = 3 (1); Ln = Yb, n = 2 (2)) and [[LnL2(THF)3]2](Ln = Sm (5); Ln = Yb (6)) in quantitative yield, respectively. Addition of 2 equiv. of hexamethylphosphoric triamide (HMPA) to a tetrahydrofuran (THF) solution of 1, 2 and 5 affords the corresponding HMPA-coordinated complexes, [[LnL1(THF)m(HMPA)n]2(THF)y](Ln = Sm, n = 2, m = 0, y = 2 (3); Ln = Yb, m = 1, n = 1, y = 6 (4)) and [[SmL2(HMPA)2]2](7) in excellent yields. The single-crystal structural analyses of 3, 4 and 7 revealed that these aryloxide lanthanide(II) complexes are dimeric with two Ln-O bridges. The coordination geometry of each lanthanide metal can be best described as a distorted trigonal bipyramid. Complexes 1-3, 5 and 7 can catalyze the ring-opening polymerization of epsilon-caprolactone (epsilon-CL), and 1-3, along with 5 show moderate activity for the ring-opening polymerization of 2,2-dimethyltrimethylene carbonate (DTC) and the copolymerization of epsilon-CL and DTC to give random copolymers with high molecular weights and relatively narrow molecular weight distributions.. PMID:15252483

  8. High-resolution electron spectroscopy of lanthanide (Ce, Pr, and Nd) complexes of cyclooctatetraene: the role of 4f electrons.

    PubMed

    Kumari, Sudesh; Roudjane, Mourad; Hewage, Dilrukshi; Liu, Yang; Yang, Dong-Sheng

    2013-04-28

    Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Møller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes.

  9. High-resolution electron spectroscopy of lanthanide (Ce, Pr, and Nd) complexes of cyclooctatetraene: The role of 4f electrons

    SciTech Connect

    Kumari, Sudesh; Roudjane, Mourad; Hewage, Dilrukshi; Yang Dongsheng; Liu Yang

    2013-04-28

    Cerium, praseodymium, and neodymium complexes of 1,3,5,7-cyclooctatetraene (COT) complexes were produced in a laser-vaporization metal cluster source and studied by pulsed-field ionization zero electron kinetic energy spectroscopy and quantum chemical calculations. The computations included the second-order Moller-Plesset perturbation theory, the coupled cluster method with single, double, and perturbative triple excitations, and the state-average complete active space self-consistent field method. The spectrum of each complex exhibits multiple band systems and is assigned to ionization of several low-energy electronic states of the neutral complex. This observation is different from previous studies of M(COT) (M = Sc, Y, La, and Gd), for which a single band system was observed. The presence of the multiple low-energy electronic states is caused by the splitting of the partially filled lanthanide 4f orbitals in the ligand field, and the number of the low-energy states increases rapidly with increasing number of the metal 4f electrons. On the other hand, the 4f electrons have a small effect on the geometries and vibrational frequencies of these lanthanide complexes.

  10. Unexpected Changes in the Population of Coordination Isomers for the Lanthanide Ion Complexes of DOTMA-Tetraglycinate.

    PubMed

    Kumas, Cemile; Fernando, W Shirangi; Zhao, Piyu; Regueiro-Figueroa, Martín; Kiefer, Garry E; Martins, André F; Platas-Iglesias, Carlos; Sherry, A Dean

    2016-09-19

    Lanthanide complexes with DOTA-tetraglycinate (DOTA-(gly)4) heavily favor the square antiprismatic (SAP) coordination isomer in aqueous solution, a structural feature that has made them useful as water-based paraCEST agents. In an effort to create amide-based paraCEST agents with rapid water exchange rates, we prepared the analogous tetraglycinate complexes with DOTMA, a ligand known to favor the twisted square antiprismatic (TSAP) coordination structures. Unexpectedly, NMR investigations show that the LnDOTMA-(gly)4 complexes, like the LnDOTA-(gly)4 complexes, also favor the SAP isomers in solution. This observation led to density functional theory (DFT) calculations in order to identify the energy terms that favor the SAP structures in lanthanide complexes formed with macrocyclic DOTA- and DOTMA-tetraamide ligands. The DFT calculations revealed that, regardless the nature of the ligand, the TSAP isomers present more negative hydration energies than the SAP counterparts. The extent to which the TSAP isomer is stabilized varies, however, depending on the ligand structure, resulting in different isomeric populations in solution. PMID:27603690

  11. Novel one-dimensional lanthanide acrylic acid complexes: an alternative chain constructed by hydrogen bonding

    NASA Astrophysics Data System (ADS)

    Li, Hui; Hu, Chang Wen

    2004-12-01

    Novel one-dimensional (1D) chains of three lanthanide complexes La(L 1) 3(CH 3OH)]·CH 3OH (L 1=(E)-3-(2-hydroxyl-phenyl)-acrylic acid) 1, La(L 2) 3(H 2O) 2]·2.75H 2O (L 2=(E)-3-(3-hydroxyl-phenyl)-acrylic acid) 2, and La(L 3) 3(CH 3OH) 2(H 2O)]·CH 3OH (L 3=(E)-3-(4-hydroxyl-phenyl)-acrylic acid) 3 are reported. The crystal structure data are as follows for 1: C 29H 29LaO 11, monoclinic, P2 1/ n, a=15.4289(12) Å, b=7.9585(6) Å, c=23.041(2) Å, β=99.657(2)°, Z=4, R1=0.0637, w R2=0.0919; for 2: C 27H 30.50LaO 13.75, triclinic, P-1, a=8.4719(17) Å, b=13.719(3) Å, c=14.570(3) Å, α=62.19(3)°, β=99.657(2)°, γ=78.22(3)°, Z=2, R1=0.0384, w R2=0.0820; and for 3: C 30H 35LaO 13, monoclinic, P2(1)/ c, a=9.5667(6) Å, b=24.3911(15) Å, c=14.0448(9) Å, β=109.245(2)°, Z=4, R1=0.0374, w R2=0.0630. All the three structure data were collected using graphite monochromated molybdenum Kα radiation and refined using full-matrix least-squares techniques on F 2. These structures show that four kinds of the carboxylato bridge modes are included in these chains to link the La(III) ions. It is the first time that it has been found that the intra-chain hydrogen bonding can construct an alternative chain even, when the coordination bridge mode is the same along the chain (complex 2). There are 2D and 3D hydrogen bonding in the crystal lattices of complexes 1- 3.

  12. Selective recovery of minor trivalent actinides from high level liquid waste by R-BTP/SiO2-P adsorbents

    NASA Astrophysics Data System (ADS)

    Sano, Yuichi; Surugaya, Naoki; Yamamoto, Masahiko

    2010-03-01

    Concerning the selective recovery of minor trivalent actinides (MA(III) = Am(III) and Cm(III)) from high level liquid waste (HLLW) by extraction chromatography, adsorption and elution behaviours of MA(III) and fission products (FP) in a nitric acid media were studied using iHex-BTP/SiO2-P adsorbents, which is expected to show high adsorption affinity for MA(III) even in concentrated HNO3 solution, such as HLLW. In the batch experiments, Pd showed strong adsorption on iHex-BTP/SiO2-P adsorbents under any concentration of HNO3. The MA(III) and heavy Ln(III) (Sm(III), Eu(III) and Gd(III)) were also adsorbed at the condition of high HNO3 concentration, but they showed no adsorption under low HNO3concentration. The separation factor for MA(III)/heavy Ln(III) took the maximum value (over 100) at around 1mol/dm3 HNO3. It was difficult to elute MA(III) or heavy Ln(III) selectively by HNO3 from the iHex-BTP/SiO2-P adsorbents degradated by γ-ray irradiation. The chromatographic separation of real HLLW by an iHex-BTP/SiO2-P column showed that MA(III) could be recovered selectively by adjusting the acidity of the feed solution, i.e. HLLW, to 1mol/dm3 and using H2O as eluant. The adsorption of Pd(II) can be decreased by the addition of appropriate complexing reagents, e.g. DTPA, into HLLW without any effects on the MA(III) adsorption.

  13. Microwave assisted synthesis, spectroscopic, electrochemical and DNA cleavage studies of lanthanide(III) complexes with coumarin based imines.

    PubMed

    Kapoor, Puja; Fahmi, Nighat; Singh, R V

    2011-12-01

    The present work stems from our interest in the synthesis, characterization and biological evaluation of lanthanide(III) complexes of a class of coumarin based imines which have been prepared by the interaction of hydrated lanthanide(III) chloride with the sodium salts of 3-acetylcoumarin thiosemicarbazone (ACTSZH) and 3-acetylcoumarin semicarbazone (ACSZH) in 1:3 molar ratio using thermal as well as microwave method. Characterization of the ligands as well as the metal complexes have been carried out by elemental analysis, melting point determinations, molecular weight determinations, magnetic moment, molar conductance, IR, (1)H NMR, (13)C NMR, electronic, EPR, X-ray powder diffraction and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and octahedral environment around metal ions. The redox behavior of one of the synthesized metal complex was investigated by cyclic voltammetry. Further, free ligands and their metal complexes have been screened for their antimicrobial as well as DNA cleavage activity. The results of these findings have been presented and discussed.

  14. Microwave assisted synthesis, spectroscopic, electrochemical and DNA cleavage studies of lanthanide(III) complexes with coumarin based imines

    NASA Astrophysics Data System (ADS)

    Kapoor, Puja; Fahmi, Nighat; Singh, R. V.

    2011-12-01

    The present work stems from our interest in the synthesis, characterization and biological evaluation of lanthanide(III) complexes of a class of coumarin based imines which have been prepared by the interaction of hydrated lanthanide(III) chloride with the sodium salts of 3-acetylcoumarin thiosemicarbazone (ACTSZH) and 3-acetylcoumarin semicarbazone (ACSZH) in 1:3 molar ratio using thermal as well as microwave method. Characterization of the ligands as well as the metal complexes have been carried out by elemental analysis, melting point determinations, molecular weight determinations, magnetic moment, molar conductance, IR, 1H NMR, 13C NMR, electronic, EPR, X-ray powder diffraction and mass spectral studies. Spectral studies confirm ligands to be monofunctional bidentate and octahedral environment around metal ions. The redox behavior of one of the synthesized metal complex was investigated by cyclic voltammetry. Further, free ligands and their metal complexes have been screened for their antimicrobial as well as DNA cleavage activity. The results of these findings have been presented and discussed.

  15. Fluorescent studies on the interaction of DNA and ternary lanthanide complexes with cinnamic acid-phenanthroline and antibacterial activities testing.

    PubMed

    Sun, Hui-Juan; Wang, Ai-Ling; Chu, Hai-Bin; Zhao, Yong-Liang

    2015-03-01

    Twelve lanthanide complexes with cinnamate (cin(-) ) and 1,10-phenanthroline (phen) were synthesized and characterized. Their compositions were assumed to be RE(cin)3 phen (RE(3+)  = La(3+) , Pr(3+) , Nd(3+) , Sm(3+) , Eu(3+) , Gd(3+) , Tb(3+) , Dy(3+) , Ho(3+) , Tm(3+) , Yb(3+) , Lu(3+) ). The interaction mode between the complexes and DNA was investigated by fluorescence quenching experiment. The results indicated the complexes could bind to DNA and the main binding mode is intercalative binding. The fluorescence quenching constants of the complexes increased from La(cin)3 phen to Lu(cin)3 phen. Additionally, the antibacterial activity testing showed that the complexes exhibited excellent antibacterial ability against Escherichia coli, and the changes of antibacterial ability are in agreement with that of the fluorescence quenching constants.

  16. Complexation of lanthanides with crown ether carboxylic acids and its applications in analytical chemistry

    SciTech Connect

    Tang, Jian.

    1989-01-01

    The extraction characteristics of trivalent lanthanides by three crown ether carboxylic acids of different lipophilicities were investigated. Extraction was found to be independent of anions and strongly dependent on pH. Quantitative extraction of lanthanides was observed in the pH range of 6-8 by all three crown ether carboxylic acids: sym-dibenzo-16-crown-5 oxyacetic acid (I), 2-(sym-dibenzo-16-crown-5-oxy)hexanoic acid (II), and 2-(sym-dibenzo-16-crown-5-oxy)stearic acid (III). Results of competitive experiments indicated that this extraction system was highly selective for lanthanides relative to other major ionic species, such as the alkali metal ions, the alkaline earth metal ions, and transition metal ions. The extraction method has been applied to the determination of low levels of lanthanides in natural waters and in biological materials. Sym-dibenzo-16-crown-5-oxyacetic acid had insufficient lipophilicity to remain in the organic phase when the pH of the aqueous phase was high and the organic to aqueous phase ratio was small. Extraction efficiency increased with the increasing lipophilicity of the crown ether carboxylic acids, which followed the order I < II < III. Using 2-(sym-dibenzo-16-crown-5-oxy)hexanoic acid as an extractant, lanthanides in some natural water and biological samples were determined by neutron activation analysis (NAA). Uranium can also be extracted by the three crown ether carboxylic acids with high efficiency. 2-(Sym-dibenzo-16-crown-5-oxy)hexanoic acid was utilized to extract uranyl ions from seawater and river water samples into chloroform, followed by back-extraction with a pH 2 nitric acid solution prior to NAA. The extraction method combined with NAA provides a sensitive method for the determination of uranium in natural waters.

  17. Synthesis and luminescence properties of hybrid organic-inorganic transparent titania thin film activated by in-situ formed lanthanide complexes

    SciTech Connect

    Wang Yige; Wang Li; Li Huanrong Liu Peng; Qin Dashan; Liu Binyuan; Zhang Wenjun; Deng Ruiping; Zhang Hongjie

    2008-03-15

    Stable transparent titania thin films were fabricated at room temperature by combining thenoyltrifluoroacetone (TTFA)-modified titanium precursors with amphiphilic triblock poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO, P123) copolymers. The obtained transparent titania thin films were systematically investigated by IR spectroscopy, PL emission and excitation spectroscopy and transmission electron microscopy. IR spectroscopy indicates that TTFA coordinates the titanium center during the process of hydrolysis and condensation. Luminescence spectroscopy confirms the in-situ formation of lanthanide complexes in the transparent titania thin film. TEM image shows that the in-situ formed lanthanide complexes were homogeneously distributed throughout the whole thin film. The quantum yield and the number of water coordinated to lanthanide metal center have been theoretically determined based on the luminescence data. - Graphical abstract: Novel stable luminescent organic-inorganic hybrid titania thin film with high transparency activated by in-situ formed lanthanide complexes have been obtained at room temperature via a simple one-pot synthesis approach by using TTFA-modified titanium precursor with amphiphilic triblock copolymer P123. The obtained hybrid thin film displays bright red (or green), near-monochromatic luminescence due to the in-situ formed lanthanide complex.

  18. Modeling the magnetic properties of lanthanide complexes: relationship of the REC parameters with Pauling electronegativity and coordination number.

    PubMed

    Baldoví, José J; Gaita-Ariño, Alejandro; Coronado, Eugenio

    2015-07-28

    In a previous study, we introduced the Radial Effective Charge (REC) model to study the magnetic properties of lanthanide single ion magnets. Now, we perform an empirical determination of the effective charges (Zi) and radial displacements (Dr) of this model using spectroscopic data. This systematic study allows us to relate Dr and Zi with chemical factors such as the coordination number and the electronegativities of the metal and the donor atoms. This strategy is being used to drastically reduce the number of free parameters in the modeling of the magnetic and spectroscopic properties of f-element complexes.

  19. Spectroscopic studies of lanthanide complexes of varying nuclearity based on a compartmentalised ligand.

    PubMed

    Olea-Román, Daniela; Bélanger-Desmarais, Nicolas; Flores-Álamo, Marcos; Bazán, Claudia; Thouin, Félix; Reber, Christian; Castillo-Blum, Silvia E

    2015-10-21

    The synthesis, characterization and solid-state luminescence spectroscopy of mononuclear (f), heterodinuclear (d-f) and heterotrinuclear (d-f-d) coordination compounds with the compartmental ligand N,N'-bis(3-hydroxyl salicylidene)benzene-1,2-diamine (H2L) are reported. The trivalent lanthanide ions Nd(III), Sm(III), Eu(III), Gd(III), Tb(III) and Dy(III) as single metal centres or in combination with either Zn(II) or Ni(II) were coordinated. Compounds are characterised by elemental analyses, IR, 1D and 2D solution (1)H and (13)C NMR spectroscopy, measurements of magnetic moments and solid state UV-Vis-NIR reflectance, luminescence and Raman spectroscopy techniques. Crystal structures of the dinuclear compounds [SmZn(O2NO)3(L)(OH2)]·EtOH and [DyZn(O2NO)2(Cl)(L)(EtOH)]·3EtOH and the trinuclear compound [TbZn2(L)2(Cl)2(OH2)](NO3)·EtOH are presented, where samarium(iii) displays a coordination number of ten, with a bicapped cubic geometry, while for the dysprosium compound a nine-coordinated environment with a tricapped trigonal prismatic geometry is shown. Their crystals belong to the triclinic system and the P1[combining macron] space group. The coordination number for terbium(iii) in the trinuclear complex is nine, with a tricapped trigonal prismatic geometry, and its crystal belongs to the monoclinic system, space group C2/c. For these three compounds, the zinc ion stabilises a penta-coordinated environment with square pyramid geometry. All mononuclear and dinuclear compounds are neutral, whereas the trinuclear complexes are ionic. The results of DFT theoretical calculations for the ligand (H2L) are used to assign the ligand singlet and triplet excited state energy levels. Luminescence studies of the neodymium compounds indicate that the ligand is a sensitizer for NIR emitters. PMID:26374465

  20. Secret lanthanides.

    PubMed

    Sturza, C M

    2014-09-15

    Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz.

  1. Secret lanthanides.

    PubMed

    Sturza, C M

    2014-09-15

    Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz. PMID:25408760

  2. Syntheses and characterization of novel lanthanide adamantine-dicarboxylate coordination complexes

    SciTech Connect

    Li Xing; Wei Danyi; Huang Shijie; Zheng Yueqing

    2009-01-15

    Hydrothermal reactions of 1,10-phenanthroline (phen), 1,3-adamantanedicarboxylic acid (H{sub 2}L) and lanthanide chlorides yielded six compounds: [Ln(L)(HL)(phen)] (Ln=Pr, 1; Nd, 2), [Ln(L)(HL)(phen)(H{sub 2}O)] (Sm, 3; Eu, 4), [Tb(L)(HL)(phen)(H{sub 2}O)]{sub 2}.2H{sub 2}O (5), [Er{sub 3}(L){sub 4}(OH)(phen)]{sub 2} (6). Compounds 1-4 are structurally featured by one-dimensional polymeric chains; 5 hold binuclear structure constructed from eight-coordinated lanthanide center LnN{sub 2}O{sub 6} of distorted bicapped trigonal prism bridged by dicarboxylate ligands; 6 shows that erbium ions are in mono and bicapped trigonal prismatic geometries, respectively, which are further connected by {mu}{sub 3}-OH to give rise to trinuclear structure. Thermogravimetric analyses of 1, 3 and 5 were performed. Fluorescent measurements of 4 and 5 were carried out, respectively. - Grapical Abstract: Hydrothermal reactions of 1,10-phenanthroline, 1,3-adamantanedicarboxylic acid and lanthanide choloride yielded a novel supramolecular architectures constructed from polyhedral LnN{sub 2}O{sub 6} of distorted bicapped trigonal prism bridged by dicarboxylate.

  3. Co-assembly and luminescence tuning of hybrids with task-specified ionic liquid encapsulating and linking lanthanide-polyoxometalates and complexes.

    PubMed

    Yan, Bing; Cuan, Jing

    2014-10-01

    A class of novel multifunctional hybrids assembled by lanthanide polyoxometalates, ionic liquid and lanthanide complexes were prepared through the reactions of ion exchange and coordination in mild conditions. These hybrids possess two luminescence centers, one is lanthanide polyoxometalates ([EuW10O36](9-) or [TbW10O36](9-)), the other is lanthanide complexes of 1,10-phenanthroline (phen) (or 2,2'-bipyridine (bpy)) and ionic liquid (1-methyl-3-propionic imidazole unit). Fourier transform infrared (FTIR) spectra, X-ray diffraction (XRD) analysis, thermo-gravimetric analysis (TGA), UV/vis diffuse reflectance spectra and photoluminescent properties are utilized to characterize these hybrid materials. The results reveal that all hybrids possess amorphous microstructures and are composed of inorganic polyoxometalates and lanthanide nitrate through chemical bonds. Most hybrids exhibit outstanding luminescent properties such as high quantum efficiency and long lifetimes. Moreover, the luminescent color of them can be tuned and even the white luminescence can be integrated. PMID:25082218

  4. Synthesis and spectroscopic properties of lanthanide nitrate complexes with a new amide-based quinoxaline-2,3-dione ligand

    NASA Astrophysics Data System (ADS)

    Song, Xue-Qin; Wang, Ya-Wen; Zheng, Jiang-Rong; Liu, Wei-Sheng; Tan, Min-Yu

    2007-11-01

    Solid complexes of lanthanide nitrate with 1,4-di( N, N-di- n-butyl-acetamido)-quinoxaline-2,3-dione (L), [Ln(NO 3) 3L·H 2O] (Ln = La, Nd, Eu, Gd, Tb, Er), have been prepared and characterized by elemental analysis, IR, UV-vis spectra and conductivity measurements. The fluorescence property of the europium complex in solid state and in MeCN, acetone, AcOEt and THF was studied. Under the excitation, the europium complex exhibited characteristic emissions of europium. The result indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion.

  5. Challenging lanthanide relaxation theory: erbium and thulium complexes that show NMR relaxation rates faster than dysprosium and terbium analogues.

    PubMed

    Funk, Alexander M; Harvey, Peter; Finney, Katie-Louise N A; Fox, Mark A; Kenwright, Alan M; Rogers, Nicola J; Senanayake, P Kanthi; Parker, David

    2015-07-01

    Measurements of the proton NMR paramagnetic relaxation rates for several series of isostructural lanthanide(III) complexes have been performed in aqueous solution over the field range 1.0 to 16.5 Tesla. The field dependence has been modeled using Bloch-Redfield-Wangsness theory, allowing values for the electronic relaxation time, Tle and the magnetic susceptibility, μeff, to be estimated. Anomalous relaxation rate profiles were obtained, notably for erbium and thulium complexes of low symmetry 8-coordinate aza-phosphinate complexes. Such behaviour challenges accepted theory and can be interpreted in terms of changes in Tle values that are a function of the transient ligand field induced by solvent collision and vary considerably between Ln(3+) ions, along with magnetic susceptibilities that deviate significantly from free-ion values. PMID:26051749

  6. Design of lanthanide fingers: compact lanthanide-binding metalloproteins.

    PubMed

    am Ende, Christopher W; Meng, Hai Yun; Ye, Mao; Pandey, Anil K; Zondlo, Neal J

    2010-08-16

    Lanthanides have interesting chemical properties; these include luminescent, magnetic, and catalytic functions. Toward the development of proteins incorporating novel functions, we have designed a new lanthanide-binding motif, lanthanide fingers. These were designed based on the Zif268 zinc finger, which exhibits a beta beta alpha structural motif. Lanthanide fingers utilize an Asp(2)Glu(2) metal-coordination environment to bind lanthanides through a tetracarboxylate peptide ligand. The iterative design of a general lanthanide-binding peptide incorporated the following key elements: 1) residues with high alpha-helix and beta-sheet propensities in the respective secondary structures; 2) an optimized big box alpha-helix N-cap; 3) a Schellman alpha-helix C-cap motif; and 4) an optional D-Pro-Ser type II' beta-turn in the beta-hairpin. The peptides were characterized for lanthanide binding by circular dichroism (CD), NMR, and fluorescence spectroscopy. In all instances, stabilization of the peptide secondary structures resulted in an increase in metal affinity. The optimized protein design was a 25-residue peptide that was a general lanthanide-binding motif; this binds all lanthanides examined in a competitive aqueous environment, with a dissociation constant of 9.3 microM for binding Er(3+). CD spectra of the peptide-lanthanide complexes are similar to those of zinc fingers and other beta beta alpha proteins. Metal binding involves residues from the N-terminal beta-hairpin and the C terminal alpha-helical segments of the peptide. NMR data indicated that metal binding induced a global change in the peptide structure. The D-Pro-Ser type II' beta-turn motif could be replaced by Thr-Ile to generate genetically encodable lanthanide fingers. Replacement of the central Phe with Trp generated genetically encodable lanthanide fingers that exhibited terbium luminescence greater than that of an EF-hand peptide.

  7. Complexation of trivalent americium and lanthanides with terdentate 'N' donor ligands: the role of rigidity in the ligand structure.

    PubMed

    Bhattacharyya, Arunasis; Gadly, Trilochan; Pathak, Priyanath; Ghosh, Sunil K; Mohapatra, Manoj; Ghanty, Tapan K; Mohapatra, Prasanta K

    2014-08-28

    A systematic study on the Ln(3+) complexation behaviour with two terdentate 'N' donor ligands of varying structural rigidity, viz. 5,6-dimethyl-(1,2,4)-triazinylbipyridine (Me2TBipy) and 5,6-dimethyl-(1,2,4)-triazinylphenanthroline (Me2TPhen), is performed in the present work by UV-Vis spectrophotometry, time resolved fluorescence spectroscopy (TRFS) and electrospray ionization mass spectrometric (ESI-MS) studies. These studies indicate the formation of a 1 : 1 complex of La(3+), 1 : 2 complexes of Eu(3+) and Er(3+) with both the ligands. Density functional theoretical (DFT) study is carried out to determine the solution phase structure of the Eu(3+) complex considering the species (from UV-Vis spectrophotometry) and C2v site symmetry around the Eu(3+) ion (from TRFS study). Me2TPhen is found to be a stronger complexing ligand as compared to Me2TBipy irrespective of the Ln(3+) ions. The solid state crystal structure of the La(3+) complex of Me2TPhen is determined using the single crystal X-ray diffraction (SCXRD) technique. The complexation of the trivalent Am(3+) ion is also studied with both these ligands using UV-Vis spectrophotometric titrations which show the formation of 1 : 2 complexes with higher complexation constant values as compared to all the Ln(3+) ions studied, indicating the selectivity of these ligands for the trivalent actinides over the lanthanides. PMID:25001925

  8. Aqueous complexation of trivalent lanthanide and actinide cations by N,N,N'{sub 2},N'-tetrakis(2-pyridylmethyl)ethylenediamine.

    SciTech Connect

    Beitz, J. V.; Ensor, D. D.; Jensen, M. P.; Morss, L. R.

    1999-06-16

    The aqueous complexation reactions of trivalent lanthanide and actinide cations with the hexadentate ligand N,N,N{prime},N{prime}-tetrakis(2-pyridylmethyl)ethylenediamine (TPEN), have been characterized using potentiometric and spectroscopic techniques in 0.1 M NaClO{sub 4} At 25 C, the stability constant of Am(TPEN){sup 3+} is two orders of magnitude larger than that of Sm(TPEN){sup 3+}, reflecting the stronger interactions of the trivalent actinide cations with softer ligands as compared to lanthanide cations.

  9. {sup 31}P NMR study of the complexation of TBP with lanthanides and actinides in solution and in a clay matrix

    SciTech Connect

    Hartzell, C.J.

    1994-07-24

    Goal was to use NMR to study TBP/lanthanide complexes in the interlayer or on edge sites of clays. Work in this laboratory yielded details of the complexation of Eu(NO{sub 3}){sub 3} and Pr(NO{sub 3}){sub 3} with TBP in hexane solution; this information is crucial to interpretation of results of NMR studies of the complexes exchanged into clays. The solution {sup 31}P-chemical shift values were improved by repeating the studies on the lanthanide salts dissolved directly into neat TBP. NMR studies of these neat solutions of the Eu(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex and the Pr(NO{sub 3}){sub 3}{lg_bullet}3TBP-complex show that the {sup 31}P chemical shift remains relatively constant for TBP: lanthanide ratios below 3: 1. At higher ratios, the chemical shift approaches that of free TBP, indicating rapid exchange of TBP between the free and complexed state. Exchange of these complexes into the clay hectorite yielded discrete {sup 31}P-NMR signals for the Eu{lg_bullet}TBP complex at -190 ppm and free TBP at -6 ppm. Adsorption of the Pr{lg_bullet}TBP complex yielded broad signals at 76 ppm for the complex and -6 ppm for free TBP. There was no evidence of exchange between the incorporated complex and the free TBP.

  10. Preparation of new fluorophore lanthanide complexes-Cloisite nanohybrids using the tricationic Pr(III), Gd(III) and Dy(III) complexes with 9,10-phenanthrenequinone.

    PubMed

    Mallakpour, Shadpour; Behnamfar, Mohammad Taghi; Dinari, Mohammad; Hadadzadeh, Hassan

    2015-02-25

    New fluorophore lanthanide complexes-Cloisite (LCs-C) nanohybrids have been prepared by the intercalation reaction of Cloisite Na(+) with the tricationic lanthanide complexes (1-3), [M(PQ)3(DMF)2(H2O)2](3+) (M=Pr(III) (1), Gd(III) (2), and Dy(III) (3); PQ=9,10-phenanthrenequinone), in aqueous solutions. The X-ray diffraction analysis of the modified clays (LCs-C) showed an increase in the interlayer distance (d) as compared to the pure Cloisite Na(+). Field-emission scanning electron microscopy (FE-SEM) was used to study the morphology of the modified clays and the results were demonstrated a homogeneous morphology for the nanohybrids. The thermal behavior of the LCs-C nanohybrids was investigated using thermogravimetric analysis. Solid-state fluorescence properties of the LCs-C nanohybrids were also investigated. The results show that all tricationic complexes have a significant fluorescence at room temperature when the complexes are adsorbed onto Cloisite.

  11. Preparation of new fluorophore lanthanide complexes-Cloisite nanohybrids using the tricationic Pr(III), Gd(III) and Dy(III) complexes with 9,10-phenanthrenequinone.

    PubMed

    Mallakpour, Shadpour; Behnamfar, Mohammad Taghi; Dinari, Mohammad; Hadadzadeh, Hassan

    2015-02-25

    New fluorophore lanthanide complexes-Cloisite (LCs-C) nanohybrids have been prepared by the intercalation reaction of Cloisite Na(+) with the tricationic lanthanide complexes (1-3), [M(PQ)3(DMF)2(H2O)2](3+) (M=Pr(III) (1), Gd(III) (2), and Dy(III) (3); PQ=9,10-phenanthrenequinone), in aqueous solutions. The X-ray diffraction analysis of the modified clays (LCs-C) showed an increase in the interlayer distance (d) as compared to the pure Cloisite Na(+). Field-emission scanning electron microscopy (FE-SEM) was used to study the morphology of the modified clays and the results were demonstrated a homogeneous morphology for the nanohybrids. The thermal behavior of the LCs-C nanohybrids was investigated using thermogravimetric analysis. Solid-state fluorescence properties of the LCs-C nanohybrids were also investigated. The results show that all tricationic complexes have a significant fluorescence at room temperature when the complexes are adsorbed onto Cloisite. PMID:25305612

  12. Secret Lanthanides

    PubMed Central

    Sturza, CM

    2014-01-01

    Abstract Lanthanides are a group of 15 chemical elements which, together with their salts, have come to be used in the last decade as homoeopathic remedies. The effective introduction of lanthanides and their salts into the clinical use, as homoeopathic remedies was based on the idea of Jan Scholten, MD to relate their physicochemical properties shown in the periodic table of elements to their homoeopathic potential. The lanthanides and their salts were prepared as homoeopathic remedies by Pharmacist Robert Münz. PMID:25408760

  13. Synthesis, crystal structures, magnetic and luminescent properties of unique 1D p-ferrocenylbenzoate-bridged lanthanide complexes

    SciTech Connect

    Yan, P.F.; Zhang, F.M.; Li, G.M.; Zhang, J.W.; Sun, W.B.; Suda, M.; Einaga, Y.

    2009-07-15

    Treatments of p-ferrocenylbenzoate [p-NaOOCH{sub 4}C{sub 6}Fc, Fc=(eta{sup 5}-C{sub 5}H{sub 5})Fe(eta{sup 5}-C{sub 5}H{sub 4})] with Ln(NO{sub 3}){sub 3}.nH{sub 2}O afford seven p-ferrocenylbenzoate lanthanide complexes {l_brace}[Ln(OOCH{sub 4}C{sub 6}Fc){sub 2}(mu{sub 2}-OOCH{sub 4}C{sub 6}Fc){sub 2}(H{sub 2}O){sub 2}](H{sub 3}O){r_brace}{sub n} [Ln=Ce (1), Pr (2), Sm (3), Eu (4), Gd (5), Tb (6) and Dy (7)]. X-ray crystallographic analysis reveals that the isomorphous complexes {l_brace}[Ce(OOCH{sub 4}C{sub 6}Fc){sub 2}(mu{sub 2}-OOCH{sub 4}C{sub 6}Fc){sub 2}(H{sub 2}O){sub 2}](H{sub 3}O){r_brace}{sub n} (1) and {l_brace}[Pr(OOCH{sub 4}C{sub 6}Fc){sub 2}(mu{sub 2}-OOCH{sub 4}C{sub 6}Fc){sub 2}(H{sub 2}O){sub 2}](H{sub 3}O){r_brace}{sub n} (2) form a unique 1D double-bridged infinite chain structure bridged by mu{sub 2}-OOCH{sub 4}C{sub 6}Fc groups. Each Ln(III) ion adopts a dodecahedron coordination environment with eight coordinated oxygen atoms from two terminal monodentate coordinated FcC{sub 6}H{sub 4}COO{sup -} units, two terminal monodentate coordinated H{sub 2}O molecules and four mu{sub 2}-{sup -}OOCH{sub 4}C{sub 6}Fc units. The luminescent spectra reveal that only 4 and 6 exhibit characteristic emissions of lanthanide ions, Eu(III) and Tb(III) ions, respectively. The variable-temperature magnetic properties of 5 and 7 suggest that a ferromagnetic coupling between spin carriers may exist in 5. - Graphical abstract: Seven p-ferrocenylbenzoate lanthanide coordination polymers were synthesized. Given is the perspective view of a unique 1D double-bridged infinite chain structure of 1, excitation and emission spectra of 6 and plots of chi{sub m}T vs. T and chi{sub m}{sup -1} vs. T of 5.

  14. Theoretical determination of spin Hamiltonians with isotropic and anisotropic magnetic interactions in transition metal and lanthanide complexes.

    PubMed

    Maurice, Rémi; Graaf, Coen de; Guihéry, Nathalie

    2013-11-21

    The determination of anisotropic magnetic parameters is a task of both experimental and theoretical interest. The added value of theoretical calculations can be crucial for analyzing experimental data by (i) allowing assessment of the validity of the phenomenological spin Hamiltonians, (ii) allowing discussion of the values of parameters extracted from experiments, and (iii) proposing rationalizations and magneto-structural correlations to better understand the relations between geometry, electronic structure, and properties. In this review, we discuss the model Hamiltonians that are used to describe magnetic properties, the computational approaches that can be used to compute magnetic parameters, and review their applications to transition metal and (to a lesser extent) lanthanide based complexes. Perspectives concerning current methodological challenges will then be presented, and finally the need for further joint experimental/theoretical efforts will be underlined.

  15. Complexation studies with lanthanides and humic acid analyzed by ultrafiltration and capillary electrophoresis-inductively coupled plasma mass spectrometry.

    PubMed

    Kautenburger, Ralf; Beck, Horst Philipp

    2007-08-01

    For the long-term storage of radioactive waste, detailed information about geo-chemical behavior of radioactive and toxic metal ions under environmental conditions is necessary. Humic acid (HA) can play an important role in the immobilisation or mobilisation of metal ions due to complexation and colloid formation. Therefore, we investigate the complexation behavior of HA and its influence on the migration or retardation of selected lanthanides (europium and gadolinium as homologues of the actinides americium and curium). Two independent speciation techniques, ultrafiltration and capillary electrophoresis coupled with inductively coupled plasma mass spectrometry (CE-ICP-MS) have been compared for the study of Eu and Gd interaction with (purified Aldrich) HA. The degree of complexation of Eu and Gd in 25 mg l(-1) Aldrich HA solutions was determined with a broad range of metal loading (Eu and Gd total concentration between 10(-6) and 10(-4) mol l(-1)), ionic strength of 10 mM (NaClO4) and different pH-values. From the CE-ICP-MS electropherograms, additional information on the charge of the Eu species was obtained by the use of 1-bromopropane as neutral marker. To detect HA in the ICP-MS and separate between HA complexed and non complexed metal ions in the CE-ICP-MS, we have halogenated the HA with iodine as ICP-MS marker. PMID:17459403

  16. Lanthanide(III) di- and tetra-nuclear complexes supported by a chelating tripodal tris(amidate) ligand.

    PubMed

    Brown, Jessie L; Jones, Matthew B; Gaunt, Andrew J; Scott, Brian L; MacBeth, Cora E; Gordon, John C

    2015-04-20

    Syntheses, structural, and spectroscopic characterization of multinuclear tris(amidate) lanthanide complexes is described. Addition of K3[N(o-PhNC(O)(t)Bu)3] to LnX3 (LnX3 = LaBr3, CeI3, and NdCl3) in N,N-dimethylformamide (DMF) results in the generation of dinuclear complexes, [Ln(N(o-PhNC(O)(t)Bu)3)(DMF)]2(μ-DMF) (Ln = La (1), Ce (2), Nd(3)), in good yields. Syntheses of tetranuclear complexes, [Ln(N(o-PhNC(O)(t)Bu)3)]4 (Ln = Ce (4), Nd(5)), resulted from protonolysis of Ln[N(SiMe3)2]3 (Ln = Ce, Nd) with N(o-PhNCH(O)(t)Bu)3. In the solid-state, complexes 1-5 exhibit coordination modes of the tripodal tris(amidate) ligand that are unique to the 4f elements and have not been previously observed in transition metal systems. PMID:25843202

  17. Lanthanide(III) di- and tetra-nuclear complexes supported by a chelating tripodal tris(amidate) ligand.

    PubMed

    Brown, Jessie L; Jones, Matthew B; Gaunt, Andrew J; Scott, Brian L; MacBeth, Cora E; Gordon, John C

    2015-04-20

    Syntheses, structural, and spectroscopic characterization of multinuclear tris(amidate) lanthanide complexes is described. Addition of K3[N(o-PhNC(O)(t)Bu)3] to LnX3 (LnX3 = LaBr3, CeI3, and NdCl3) in N,N-dimethylformamide (DMF) results in the generation of dinuclear complexes, [Ln(N(o-PhNC(O)(t)Bu)3)(DMF)]2(μ-DMF) (Ln = La (1), Ce (2), Nd(3)), in good yields. Syntheses of tetranuclear complexes, [Ln(N(o-PhNC(O)(t)Bu)3)]4 (Ln = Ce (4), Nd(5)), resulted from protonolysis of Ln[N(SiMe3)2]3 (Ln = Ce, Nd) with N(o-PhNCH(O)(t)Bu)3. In the solid-state, complexes 1-5 exhibit coordination modes of the tripodal tris(amidate) ligand that are unique to the 4f elements and have not been previously observed in transition metal systems.

  18. Lanthanide(III) di- and tetra-nuclear complexes supported by a chelating tripodal tris(amidate) ligand

    DOE PAGES

    Brown, Jessie L.; Jones, Matthew B.; Gaunt, Andrew J.; Scott, Brian L.; MacBeth, Cora E.; Gordon, John C.

    2015-04-06

    Syntheses, structural, and spectroscopic characterization of multinuclear tris(amidate) lanthanide complexes is described. Addition of K3[N(o-PhNC(O)tBu)3] to LnX3 (LnX3 = LaBr3, CeI3, and NdCl3) in N,N-dimethylformamide (DMF) results in the generation of dinuclear complexes, [Ln(N(o-PhNC(O)tBu)3)(DMF)]2(μ-DMF) (Ln = La (1), Ce (2), Nd(3)), in good yields. Syntheses of tetranuclear complexes, [Ln(N(o-PhNC(O)tBu)3)]4 (Ln = Ce (4), Nd(5)), resulted from protonolysis of Ln[N(SiMe3)2]3 (Ln = Ce, Nd) with N(o-PhNCH(O)tBu)3. As a result, in the solid-state, complexes 1–5 exhibit coordination modes of the tripodal tris(amidate) ligand that are unique to the 4f elements and have not been previously observed in transition metal systems.

  19. Lanthanide(III) di- and tetra-nuclear complexes supported by a chelating tripodal tris(amidate) ligand

    SciTech Connect

    Brown, Jessie L.; Jones, Matthew B.; Gaunt, Andrew J.; Scott, Brian L.; MacBeth, Cora E.; Gordon, John C.

    2015-04-06

    Syntheses, structural, and spectroscopic characterization of multinuclear tris(amidate) lanthanide complexes is described. Addition of K3[N(o-PhNC(O)tBu)3] to LnX3 (LnX3 = LaBr3, CeI3, and NdCl3) in N,N-dimethylformamide (DMF) results in the generation of dinuclear complexes, [Ln(N(o-PhNC(O)tBu)3)(DMF)]2(μ-DMF) (Ln = La (1), Ce (2), Nd(3)), in good yields. Syntheses of tetranuclear complexes, [Ln(N(o-PhNC(O)tBu)3)]4 (Ln = Ce (4), Nd(5)), resulted from protonolysis of Ln[N(SiMe3)2]3 (Ln = Ce, Nd) with N(o-PhNCH(O)tBu)3. As a result, in the solid-state, complexes 1–5 exhibit coordination modes of the tripodal tris(amidate) ligand that are unique to the 4f elements and have not been previously observed in transition metal systems.

  20. Photofragmentation of Gas-Phase Lanthanide Cyclopentadienyl Complexes: Experimental and Time-Dependent Excited-State Molecular Dynamics

    PubMed Central

    2015-01-01

    Unimolecular gas-phase laser-photodissociation reaction mechanisms of open-shell lanthanide cyclopentadienyl complexes, Ln(Cp)3 and Ln(TMCp)3, are analyzed from experimental and computational perspectives. The most probable pathways for the photoreactions are inferred from photoionization time-of-flight mass spectrometry (PI-TOF-MS), which provides the sequence of reaction intermediates and the distribution of final products. Time-dependent excited-state molecular dynamics (TDESMD) calculations provide insight into the electronic mechanisms for the individual steps of the laser-driven photoreactions for Ln(Cp)3. Computational analysis correctly predicts several key reaction products as well as the observed branching between two reaction pathways: (1) ligand ejection and (2) ligand cracking. Simulations support our previous assertion that both reaction pathways are initiated via a ligand-to-metal charge-transfer (LMCT) process. For the more complex chemistry of the tetramethylcyclopentadienyl complexes Ln(TMCp)3, TMESMD is less tractable, but computational geometry optimization reveals the structures of intermediates deduced from PI-TOF-MS, including several classic “tuck-in” structures and products of Cp ring expansion. The results have important implications for metal–organic catalysis and laser-assisted metal–organic chemical vapor deposition (LCVD) of insulators with high dielectric constants. PMID:24910492

  1. Impact of the Kohn-Sham Delocalization Error on the 4f Shell Localization and Population in Lanthanide Complexes.

    PubMed

    Duignan, Thomas J; Autschbach, Jochen

    2016-07-12

    The extent of ligand to metal donation bonding and mixing of 4f (and 5d) orbitals with ligand orbitals is studied by Kohn-Sham (KS) calculations for LaX3 (X = F, Cl, Br, I), GdX3, and LuX3 model complexes, CeCl6(2-), YbCp3, and selected lanthanide complexes with larger ligands. The KS delocalization error (DE) is quantified via the curvature of the energy for noninteger electron numbers. The extent of donation bonding and 4f-ligand mixing correlates well with the DE. For Lu complexes, the DE also correlates with the extent of mixing of ligand and 4f orbitals in the canonical molecular orbitals (MOs). However, the localized set of MOs and population analyses indicate that the closed 4f shell is localized. Attempts to create situations where mixing of 4f and ligand orbitals occurs due to a degeneracy of fragment orbitals were unsuccessful. For La(III) and, in particular, for Ce(IV), Hartree-Fock, KS, and coupled cluster singles and doubles calculations are in agreement in that excess 4f populations arise from ligand donation, along with donation into the 5d shell. Likewise, KS calculations for all systems with incompletely filled 4f shells, even those with "optimally tuned" functionals affording a small DE, produce varying degrees of excess 4f populations which may be only partially attributed to 5d polarization.

  2. Impact of the Kohn-Sham Delocalization Error on the 4f Shell Localization and Population in Lanthanide Complexes.

    PubMed

    Duignan, Thomas J; Autschbach, Jochen

    2016-07-12

    The extent of ligand to metal donation bonding and mixing of 4f (and 5d) orbitals with ligand orbitals is studied by Kohn-Sham (KS) calculations for LaX3 (X = F, Cl, Br, I), GdX3, and LuX3 model complexes, CeCl6(2-), YbCp3, and selected lanthanide complexes with larger ligands. The KS delocalization error (DE) is quantified via the curvature of the energy for noninteger electron numbers. The extent of donation bonding and 4f-ligand mixing correlates well with the DE. For Lu complexes, the DE also correlates with the extent of mixing of ligand and 4f orbitals in the canonical molecular orbitals (MOs). However, the localized set of MOs and population analyses indicate that the closed 4f shell is localized. Attempts to create situations where mixing of 4f and ligand orbitals occurs due to a degeneracy of fragment orbitals were unsuccessful. For La(III) and, in particular, for Ce(IV), Hartree-Fock, KS, and coupled cluster singles and doubles calculations are in agreement in that excess 4f populations arise from ligand donation, along with donation into the 5d shell. Likewise, KS calculations for all systems with incompletely filled 4f shells, even those with "optimally tuned" functionals affording a small DE, produce varying degrees of excess 4f populations which may be only partially attributed to 5d polarization. PMID:27224494

  3. Solution and Structural Investigations of Ligand Preorganization in Trivalent Lanthanide Complexes of Bicyclic Malonamides

    SciTech Connect

    Parks, Bevin W.; Gilbertson, Robert D.; Hutchison, J. E.; Rather Healey, Elisabeth; Weakley, Timothy J R; Rapko, Brian M.; Hay, Benjamin P.; Sinkov, Sergei I.; Broker, Grant A.; Rogers, Robin D.

    2006-02-20

    This report describes an investigation into the coordination chemistry of trivalentlanthanides in solution and the solid state with acyclic and preorganized bicyclic malonamide ligands. Two experimental investigations were performed: solution bindingaffinities were determined through single-phase spectrophotometric titrations and the extent of conformational change upon binding was investigated with single-crystal X-raycrystallography. Both experimental methods compare the bicyclic malonamide (BMA), which is designed to be preorganized for binding trivalent lanthanides, to an analogousacyclic malonamide. Results from the spectrophotometric titrations indicate that BMA exhibits a 10-100 times increase in binding affinity to Ln(III) over acyclic malonamide.In addition, BMA forms compounds with high ligand-metal ratios, even when competing with water and nitrate ligands for binding sites. The crystal structures exhibit nosignificant differences in the nature of the binding between Ln(III) and the BMA or acyclic malonamide. These results support the conclusion that rational ligand design canlead to compounds that enhance the binding affinities within a ligand class.

  4. Structure variation and luminescence properties of lanthanide complexes with 1,9-bis [2-(2'-picolylaminoformyl)-1,4,7,9-tetraoxadecane

    SciTech Connect

    Song Xueqin; Zang Zhipeng; Liu Weisheng; Zhang Yujie

    2009-04-15

    Using 1,9-salicylamide bissubstituted oxadecane ligand, 1,9-bis [2-(2'-picolylaminoformyl)-1,4,7,9-tetraoxadecane (L), two novel lanthanide complexes have been prepared and well characterized by means of elemental analysis, IR spectroscopy, UV-vis spectroscopy, TGA analysis and single-crystal X-ray diffraction. {l_brace}[PrL(NO{sub 3}){sub 3}(H{sub 2}O){sub 2}].CH{sub 3}OH{r_brace}{sub n} is a 1D zigzag polymer with three-dimensional supramolecular structure formed by hydrogen bonds, while [EuL(NO{sub 3}){sub 3}(H{sub 2}O)]{sub n} is a linear coordination polymer and present an interesting supramolecular double chain, which are very different from the structure of terbium complex reported before. The result reported herein demonstrated that steric crowding associated with the decreasing lanthanide ion radius causes changes of the conformation of the ligand as well as structures. Luminescence studies for the Eu(III) complexes demonstrated that the salicylamide ligand also exhibits a good antennae effect for the Eu(III) ion due to efficient intersystem crossing and ligand-to-metal energy transfer and the Eu(III) ion is well shielded from the surrounding environment. - Graphical abstract: Structure variation and luminescence properties of lanthanide complexes with 1,9-bis [2-(2'-picolylaminoformyl)-1,4,7,9-tetraoxadecane.

  5. Transparent volumetric three-dimensional image display based on the luminescence of a spinning sheet with dissolved Lanthanide(III) complexes.

    PubMed

    Hisatake, Shintaro; Suda, Sachio; Takahara, Jyunichi; Kobayashi, Tetsuro

    2007-05-28

    We have developed a new type of transparent volumetric three-dimensional (3D) image display in which a thin photopolymer sheet containing Lanthanide(III) complexes is used as a rotational screen. The Lanthanide(III) complexes used in our system are Eu(TTA)(3) Phen, designed for achieving red luminescence (615nm) for an excitation light of 395 nm. An arbitrary luminous point (voxel) is identified by controlling the excitation laser beam direction in synchronization with the photopolymer sheet rotation. The full colorization of the proposed volumetric 3D image display can be realized by using, for example, Eu(TTA)(3) Phen, Tb(ACAC)(3) Phen, and Coumarin 337, simultaneously.

  6. Tetranuclear lanthanide (III) complexes containing dimeric subunits: single-molecule magnet behavior for the Dy4 analogue.

    PubMed

    Chandrasekhar, Vadapalli; Das, Sourav; Dey, Atanu; Hossain, Sakiat; Sutter, Jean-Pascal

    2013-10-21

    The reaction of the lanthanide(III) salts [Dy(III), Tb(III), and Gd (III)] with a hetero donor chelating ligand N'-(2-hydroxy-3-methoxybenzylidene)-6-(hydroxymethyl) picolinohydrazide (LH3) and pivalic acid (PivH) in the presence of tetra-n-butylammonium hydroxide (TBAH) afforded the tetranuclear Ln(III) coordination compounds, [Ln4(LH)2(LH2)2(μ2-η(1)η(1)Piv)2(η(1)Piv)4]·2CHCl3 [Ln = Dy(1), Tb(2), and Gd(3)]. The molecular structure of these complexes reveals that the tetranuclear derivatives are composed of two dinuclear subunits which are interconnected through the coordination action of the picolinoyl hydrazine ligand. Within each subunit two different types of Ln(III) ions are present. One of these is eight-coordinate in a distorted triangular dodecahedral geometry while the other is nine-coordinate in a distorted spherical capped square antiprism geometry. Alternating current (ac) susceptibility measurements of complex 1 reveal a frequency- and temperature-dependent two step out-of-phase signals under 1kOe DC field which is characteristic of a single-molecule magnet (SMM) behavior. Analysis of the magnetic data afforded the anisotropic barriers and relaxation times: Δ/kB = 62.6 K, τ0 = 8.7 × 10(-7) s; Δ/kB = 26.3 K, τ0 = 1.26 × 10(-6) s for the slow and fast relaxations respectively. PMID:24111517

  7. Lanthanide Complexes with Multidentate Oxime Ligands as Single-Molecule Magnets and Atmospheric Carbon Dioxide Fixation Systems.

    PubMed

    Hołyńska, Małgorzata; Clérac, Rodolphe; Rouzières, Mathieu

    2015-09-14

    The synthesis, structure, and magnetic properties of five lanthanide complexes with multidentate oxime ligands are described. Complexes 1 and 2 (1: [La2 (pop)2 (acac)4 (CH3 OH)], 2: [Dy2 (pop)(acac)5 ]) are synthesized from the 2-hydroxyimino-N-[1-(2-pyridyl)ethylidene]propanohydrazone (Hpop) ligand, while 3, 4, and 5 (3: [Dy2 (naphthsaoH)2 (acac)4 H(OH)]⋅0.85 CH3 CN⋅1.58 H2 O; 4: [Tb2 (naphthsaoH)2 (acac)4 H(OH)]⋅0.52 CH3 CN⋅1.71 H2 O; 5: [La6 (CO3 )2 (naphthsao)5 (naphthsaoH)0.5 (acac)8 (CO3 )0.5 (CH3 OH)2.76 H5.5 (H2 O)1.24 ]⋅2.39 CH3 CN⋅0.12 H2 O) contain 1-(1-hydroxynaphthalen-2-yl)-ethanone oxime (naphthsaoH2 ). In 1-4, dinuclear [Ln2 ] complexes crystallize, whereas hexanuclear La(III) complex 5 is formed after fixation of atmospheric carbon dioxide. Dy(III) -based complexes 2 and 3 display single-molecule-magnet properties with energy barriers of 27 and 98 K, respectively. The presence of a broad and unsymmetrical relaxation mode observed in the ac susceptibility data for 3 suggest two different dynamics of the magnetization which might be a consequence of independent relaxation processes of the two different Dy(3+) ions.

  8. Azobenzene-derived tris-β-diketonate lanthanide complexes: reversible trans-to-cis photoisomerization in solution and solid state.

    PubMed

    Lin, Li-Rong; Wang, Xuan; Wei, Gao-Ning; Tang, Hui-Hui; Zhang, Hui; Ma, Li-Hua

    2016-10-14

    Novel azobenzene-derived β-diketonates (4,4,5,5,6,6,6-heptafluoro-1-azobenzene-1,3-hexanedione (LA), 4,4,5,5,6,6,6-heptafluoro-1-(4-dimethylamino)azobenzene-1,3-hexanedione (LB)) were designed and their complexes with lanthanide cations (La(3+), Eu(3+), Gd(3+), Yb(3+)) were prepared and characterized by (1)H NMR, FT-IR, and elemental analysis. Three of the complexes were crystallized successfully and identified by X-ray diffraction. It was significant to find that LA showed remarkably reversible trans-to-cis isomerization properties, however, LB, bearing an electron donor compared with LA, slowed down the isomerization to an extent. The presence of Ln(iii) enhanced the reversible trans-to-cis isomerization properties of both LA and LB a little upon photoirradiation in organic solvents, and amazingly increased the fatigue resistance. In addition, the complexes doped in polymethyl methacrylate (PMMA) films produced a similar phenomenon as well as when in solution. Theoretical calculations based on time dependent density functional theory (TD-DFT) were performed for geometry optimization and to determine the excitation energies of LA and LB to gain further insight into the electronic structure of the complexes, and the data were consistent with the experimental results. The excellent reversible photoisomerization properties of the newly designed Ln(iii) complexes can offer important advantages that will help with the further study of these materials to reach their full potential in applications such as molecular switching devices.

  9. Photo-induced DNA cleavage activity and remarkable photocytotoxicity of lanthanide(III) complexes of a polypyridyl ligand.

    PubMed

    Hussain, Akhtar; Gadadhar, Sudarshan; Goswami, Tridib K; Karande, Anjali A; Chakravarty, Akhil R

    2012-01-21

    Lanthanide(III) complexes [Ln(pyphen)(acac)(2)(NO(3))] (1, 2), [Ln(pydppz)(acac)(2)(NO(3))] (3, 4) and [La(pydppz)(anacac)(2)(NO(3))] (5), where Ln is La(III) (in 1, 3, 5) and Gd(III) (in 2, 4), pyphen is 6-(2-pyridyl)-1,10-phenanthroline, pydppz is 6-(2-pyridyl)-dipyrido[3,2-a:2',3'-c]phenazine, anacac is anthracenylacetylacetonate and acac is acetylacetonate, were prepared, characterized and their DNA photocleavage activity and photocytotoxicity studied. The crystal structure of complex 2 displays a GdO(6)N(3) coordination. The pydppz complexes 3-5 show an electronic spectral band at ~390 nm in DMF. The La(III) complexes are diamagnetic, while the Gd(III) complexes are paramagnetic with seven unpaired electrons. The molar conductivity data suggest 1 : 1 electrolytic nature of the complexes in aqueous DMF. They are avid binders to calf thymus DNA giving K(b) in the range of 5.4 × 10(4)-1.2 × 10(6) M(-1). Complexes 3-5 efficiently cleave supercoiled DNA to its nicked circular form in UV-A light of 365 nm via formation of singlet oxygen ((1)O(2)) and hydroxyl radical (HO˙) species. Complexes 3-5 also exhibit significant photocytotoxic effect in HeLa cancer cells giving respective IC(50) value of 0.16(±0.01), 0.15(±0.01) and 0.26±(0.02) μM in UV-A light of 365 nm, while they are less toxic in dark with an IC(50) value of >3 μM. The presence of an additional pyridyl group makes the pydppz complexes more photocytotoxic than their dppz analogues. FACS analysis of the HeLa cells treated with complex 4 shows apoptosis as the major pathway of cell death. Nuclear localization of complex 5 having an anthracenyl moiety as a fluorophore is evidenced from the confocal microscopic studies.

  10. Synthesis, characterization and DNA interaction studies of complexes of lanthanide nitrates with tris{2-[(3,4-dihydroxybenzylidene)imino]ethyl}amine

    NASA Astrophysics Data System (ADS)

    Liu, Min; Yuan, Wen-bing; Zhang, Qi; Yan, Lan; Yang, Ru-dong

    2008-10-01

    A new tripodal, hydroxyl-rich ligand, tris{2-[(3,4-dihydroxybenzylidene)imino]ethyl}amine (L), and its complexes with lanthanide nitrates were synthesized. These complexes which are stable in air with the general formula of [LnL(NO 3) 2]NO 3·H 2O (Ln = La, Sm, Eu, Gd, Y) were characterized by molar conductivity, elemental analysis, IR spectra and thermal analysis. The NO 3- groups coordinated to lanthanide mono-dentately, and the coordination number in these complexes may be 8. The interaction of complexes with DNA were investigated by ultraviolet and fluorescent spectra, which showed that the binding mode of complexes with DNA was intercalation, and the binding affinity with DNA were La(III) complex > Sm(III) complex > Eu(III) complex > Gd(III) complex > Y(III) complex. Based on these results, it can be shown that the La(III)complex is promising candidate for therapeutic reagents and DNA probes.

  11. Nonaqueous method for dissolving lanthanide and actinide metals

    DOEpatents

    Crisler, L.R.

    1975-11-11

    Lanthanide and actinide beta-diketonate complex molecular compounds are produced by reacting a beta-diketone compound with a lanthanide or actinide element in the elemental metallic state in a mixture of carbon tetrachloride and methanol.

  12. Bromide complexation by the Eu(III) lanthanide cation in dry and humid ionic liquids: a molecular dynamics PMF study.

    PubMed

    Chaumont, Alain; Wipff, Georges

    2012-05-14

    We report a molecular dynamics study on the EuBr(n)(3-n) complexes (n=0 to 6) formed upon complexation of Br(-) by Eu(3+) in the [BMI][PF(6)], [BMI][Tf(2)N] and [MeBu(3)N][Tf(2)N] ionic liquids (ILs), to compare the effect of the IL anion (PF(6)(-) versus Tf(2)N(-)), the IL cation (BMI(+) versus MeBu(3)N(+)) and the "IL humidity" on their solvation and stability. In "dry" solutions all complexes remain stable and the first coordination shell of Eu(3+) is purely anionic (Br(-) and IL anions), surrounded by IL cations (BMI(+) or MeBu(3)N(+) ions). Long range "onion type" solvation features (up to 20 Å from Eu(3+)), with alternating cation-rich and anion-rich solvent shells, are observed around the different complexes. The comparison of gas phase-optimized structures of EuBr(n)(3-n) complexes (that are unstable for n=5 and 6) with those observed in solution points to the importance of solvation forces on the nature of the complex, with a higher stabilization by imidazolium- than by ammonium-based dry ILs. Adding water to the IL has different effects, depending on the IL. In the highly hygroscopic [BMI][PF(6)] IL, Br(-) ligands are displaced by water, to finally form Eu(H(2)O)(9)(3+). In the less "humid" [BMI][Tf(2)N], the EuBr(n)(3-n) complexes do not dissociate and coordinate at most 1-2 H(2)O molecules. We also calculated the free-energy profiles (Potential of Mean Force calculations) for the stepwise complexation of Br(-), and found significant solvent effects. EuBr(6)(3-) is predicted to form in both [BMI][PF(6)] and [BMI][Tf(2)N], but not in [MeBu(3)N][Tf(2)N], mainly due to weaker interactions with the cationic solvation shell. First steps are found to be more exergonic in the PF(6)(-)- than in the Tf(2)N(-)-based IL. Molecular dynamics (MD) comparisons between ILs and classical solvents (acetonitrile and water) are also reported, affording good agreement with the experimental observations of Br(-) complexation by trivalent lanthanides in these classical

  13. meso-Phenyltetrabenzotriazaporphyrin based double-decker lanthanide(III) complexes: synthesis, structure, spectral properties and electrochemistry.

    PubMed

    Pushkarev, Victor E; Kalashnikov, Valery V; Tolbin, Alexander Yu; Trashin, Stanislav A; Borisova, Nataliya E; Simonov, Sergey V; Rybakov, Victor B; Tomilova, Larisa G; Zefirov, Nikolay S

    2015-10-01

    A series of half-sandwich and sandwich-type lanthanide(III) complexes have been prepared using tetrabenzotriazaporphyrin ligands. Reaction of 27-phenyl-29H,31H-tetrabenzo[b,g,l,q][5,10,15]-triazaporphyrin (PhTBTAPH2, 1) with salts [LnX3]·nH2O (Ln = Eu (a), Lu (b); X = OAc, acac) afforded the single- and homoleptic double-deckers (PhTBTAP)LnOAc (2) and (PhTBTAP)2Ln (3) respectively. Heteroleptic double-decker compounds (PhTBTAP)LnPc (4a,b) were obtained upon interaction of 1 with the corresponding Ln mono(phthalocyaninates). An unexpected formation of partially and completely dephenylated co-products 5 and 6 has been detected in the synthesis of sandwich 3, while the possibility of the dearylation of the half-sandwich compound 2 has been demonstrated as well. A more predictable yet firstly observed formation of the triple-decker compound (PhTBTAP)3Eu2 (7) has also been found. Structural studies of 3 supported by 1H NMR spectra, XRD analysis and DFT theoretical calculations reveal that the Eu complex 3a is formed as a single isomer, while the lutetium compound 3b represents an inseparable mixture of two rotational isomers with virtually identical spectral characteristics. The double-decker compounds 3 and 4 reveal intrinsic UV-Vis/NIR absorption as well as peculiar electrochromic behavior. The heteroleptic derivatives 4 generally show intermediate spectral and electrochemical properties with respect to their homoleptic relatives. PMID:26332086

  14. Mechanisms of dielectric polarization in thermotropic liquid-crystalline complexes based on lanthanides

    NASA Astrophysics Data System (ADS)

    Dobrun, L. A.; Kovshik, A. P.; Ryumtsev, E. I.; Knyazev, A. A.; Galyametdinov, Yu. G.

    2016-06-01

    The components of the dielectric constant of a terbium-based liquid-crystalline complex have been measured in the frequency range of 350-5 × 106 Hz. The magnitude and sign of the dielectric anisotropy of the complex have been determined. Dispersion of the dielectric constants in the liquid-crystalline and isotropic phases has been found. The mechanisms responsible for the relaxation phenomena that appear in the studied sample have been determined. The time of dielectric relaxation, the activation energy, and the dipole moment of the complex have been obtained.

  15. Computational study of organo-cesium complexes and the possibility of lanthanide/actinide ions substitution

    NASA Astrophysics Data System (ADS)

    Rabanal-León, Walter A.; Martinez-Ariza, Guillermo; Roberts, Sue A.; Hulme, Christopher; Arratia-Pérez, Ramiro

    2015-11-01

    Relativistic DFT calculations suggest that two organo-cesium complexes studied herein afford large HOMO-LUMO gaps of around 2.4 eV with the PBE xc-functional, which accounts for their stability. Energy decomposition studies suggest these two complexes are largely ionic with about 20% covalency. However, when the Cs+ ions are substituted by the isoelectronic La3+ and Th4+, their predicted ionicity decreases significantly. The significant increase in covalence indicates that employing Ugi reaction cascades that afford tetramic acid-based organo-cesium complexes may be extended to La3+ and Th4+ organometallics.

  16. Self-aggregated dinuclear lanthanide(III) complexes as potential bimodal probes for magnetic resonance and optical imaging.

    PubMed

    Regueiro-Figueroa, Martín; Nonat, Aline; Rolla, Gabriele A; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Charbonnière, Loïc J; Botta, Mauro; Platas-Iglesias, Carlos

    2013-08-26

    Homodinuclear lanthanide complexes (Ln = La, Eu, Gd, Tb, Yb and Lu) derived from a bis-macrocyclic ligand featuring two 2,2',2''-(1,4,7,10-tetraazacyclododecane-1,4,7-triyl)triacetic acid chelating sites linked by a 2,6-bis(pyrazol-1-yl)pyridine spacer (H2L(3)) were prepared and characterized. Luminescence lifetime measurements recorded on solutions of the Eu(III) and Tb(III) complexes indicate the presence of one inner-sphere water molecule coordinated to each metal ion in these complexes. The overall luminescence quantum yields were determined (ϕ H2O = 0.01 for [Eu2(L(3))] and 0.50 for [Tb2(L(3))] in 0.01 M TRIS/HCl, pH 7.4; TRIS = tris(hydroxymethyl)aminomethane), pointing to an effective sensitization of the metal ion by the bispyrazolylpyridyl unit of the ligand, especially with Tb. The nuclear magnetic relaxation dispersion (NMRD) profiles recorded for [Gd2(L(3))] are characteristic of slowly tumbling systems, showing a low-field plateau and a broad maximum around 30 MHz. This suggests the occurrence of aggregation of the complexes giving rise to slowly rotating species. A similar behavior is observed for the analogous Gd(III) complex containing a 4,4'-dimethyl-2,2'-bipyridyl spacer ([Gd2(L(1))]). The relaxivity of [Gd2(L(3))] recorded at 0.5 T and 298 K (pH 6.9) amounts to 13.7 mM(-1)  s(-1). The formation of aggregates has been confirmed by dynamic light scattering (DLS) experiments, which provided mean particle sizes of 114 and 38 nm for [Gd2(L(1))] and [Gd2(L(3))], respectively. TEM images of [Gd2(L(3))] indicate the formation of nearly spherical nanosized aggregates with a mean diameter of about 41 nm, together with some nonspherical particles with larger size.

  17. Potentiometric study of binary complexes of 3-[(1 R)-1-hydroxy-2-(methylamino)ethyl]phenol hydrochloride with some lanthanide ions in aqueous and mixed solutions

    NASA Astrophysics Data System (ADS)

    Sharma, S. S.; Kadia, M. V.

    2014-12-01

    The complexation of lanthanide ions (Y3+, La3+, Ce3+, Pr3+, Nd3+, Sm3+, Gd3+, Tb3+, and Dy3+) with 3-[(1 R)-1-hydroxy-2-(methylamino)ethyl]phenol hydrochloride was studied at different temperatures and different ionic strengths in aqueous solutions by Irving-Rossotti pH titration technique. Stepwise calculation, PKAS and BEST Fortran IV computer programs were used for determination of proton-ligand and metal-ligand stability constants. The formation of species like MA, MA2, and MA(OH) is considered in SPEPLOT. Thermodynamic parameters of complex formation (Δ G, Δ H, and Δ S) are also evaluated. Negative Δ G and Δ H values indicate that complex formation is favourable in these experimental conditions. The stability of complexes is also studied at in different solvent-aqueous (vol/vol). The stability series of lanthanide complexes has shown to have the "gadolinium break." Stability of complexes decreases with increase in ionic strength and temperature. Effect of systematic errors like effect of dissolved carbon dioxide, concentration of alkali, concentration of acid, concentration of ligand and concentration of metal have also been explained.

  18. Construction of Polynuclear Lanthanide (Ln = Dy(III), Tb(III), and Nd(III)) Cage Complexes Using Pyridine-Pyrazole-Based Ligands: Versatile Molecular Topologies and SMM Behavior.

    PubMed

    Bala, Sukhen; Sen Bishwas, Mousumi; Pramanik, Bhaskar; Khanra, Sumit; Fromm, Katharina M; Poddar, Pankaj; Mondal, Raju

    2015-09-01

    Employment of two different pyridyl-pyrazolyl-based ligands afforded three octanuclear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core. Relatively less common semirigid pyridyl-pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers. It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl-pyrazol. We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites. The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions. Alternating current (ac) susceptibility measurements of the two dysprosium complexes display frequency- and temperature-dependent out-of-phase signals in zero and 0.5 T direct current field, a typical characteristic feature of single-molecule magnet (SMM) behavior, indicating different energy reversal barriers due to different molecular topologies. Another aspect of this work is the occurrence of the not-so-common SMM behavior of the terbium complex, further confirmed by ac susceptibility measurement. PMID:26347289

  19. Construction of Polynuclear Lanthanide (Ln = Dy(III), Tb(III), and Nd(III)) Cage Complexes Using Pyridine-Pyrazole-Based Ligands: Versatile Molecular Topologies and SMM Behavior.

    PubMed

    Bala, Sukhen; Sen Bishwas, Mousumi; Pramanik, Bhaskar; Khanra, Sumit; Fromm, Katharina M; Poddar, Pankaj; Mondal, Raju

    2015-09-01

    Employment of two different pyridyl-pyrazolyl-based ligands afforded three octanuclear lanthanide(III) (Ln = Dy, Tb) cage compounds and one hexanuclear neodymium(III) coordination cage, exhibiting versatile molecular architectures including a butterfly core. Relatively less common semirigid pyridyl-pyrazolyl-based asymmetric ligand systems show an interesting trend of forming polynuclear lanthanide cage complexes with different coordination environments around the metal centers. It is noteworthy here that construction of lanthanide complex itself is a challenging task in a ligand system as soft N-donor rich as pyridyl-pyrazol. We report herein some lanthanide complexes using ligand containing only one or two O-donors compare to five N-coordinating sites. The resultant multinuclear lanthanide complexes show interesting magnetic and spectroscopic features originating from different spatial arrangements of the metal ions. Alternating current (ac) susceptibility measurements of the two dysprosium complexes display frequency- and temperature-dependent out-of-phase signals in zero and 0.5 T direct current field, a typical characteristic feature of single-molecule magnet (SMM) behavior, indicating different energy reversal barriers due to different molecular topologies. Another aspect of this work is the occurrence of the not-so-common SMM behavior of the terbium complex, further confirmed by ac susceptibility measurement.

  20. Luminescent lanthanide complexes with 4-acetamidobenzoate: Synthesis, supramolecular assembly via hydrogen bonds, crystal structures and photoluminescence

    SciTech Connect

    Yin Xia; Fan Jun; Wang Zhihong; Zheng Shengrun; Tan Jingbo; Zhang Weiguang

    2011-07-15

    Four new luminescent complexes, namely, [Eu(aba){sub 2}(NO{sub 3})(C{sub 2}H{sub 5}OH){sub 2}] (1), [Eu(aba){sub 3}(H{sub 2}O){sub 2}].0.5 (4, 4'-bpy).2H{sub 2}O (2), [Eu{sub 2}(aba){sub 4}(2, 2'-bpy){sub 2}(NO{sub 3}){sub 2}].4H{sub 2}O (3) and [Tb{sub 2}(aba){sub 4}(phen){sub 2}(NO{sub 3}){sub 2}].2C{sub 2}H{sub 5}OH (4) were obtained by treating Ln(NO{sub 3}){sub 3}.6H{sub 2}O and 4-acetamidobenzoic acid (Haba) with different coligands (4, 4'-bpy=4, 4'-bipyridine, 2, 2'-bpy=2, 2'-bipyridine, and phen=1, 10-phenanthroline). They exhibit 1D chains (1-2) and dimeric structures (3-4), respectively. This structural variation is mainly attributed to the change of coligands and various coordination modes of aba molecules. Moreover, the coordination units are further connected via hydrogen bonds to form 2D even 3D supramolecular networks. These complexes show characteristic emissions in the visible region at room temperature. In addition, thermal behaviors of four complexes have been investigated under air atmosphere. The relationship between the structures and physical properties has been discussed. - Graphical abstract: Structure variation of four complexes is attributed to the change of coligands and various coordination modes of aba molecules. Moreover, they show characteristic emissions in the visible region. Highlights: > Auxiliary ligands have played the crucial roles on the structures of the resulting complexes. > Isolated structure units are further assembled via H-bonds to form supramolecular networks. > These solid-state complexes exhibit strong, characteristic emissions in the visible region.

  1. Efficient Layers of Emitting Ternary Lanthanide Complexes for Fabricating Red, Green, and Yellow OLEDs.

    PubMed

    Ahmed, Zubair; Iftikhar, Khalid

    2015-12-01

    A series of novel nona- and octacoordinate highly volatile and luminescent complexes, [Eu(hfaa)3(indazole)3] and [Ln(hfaa)3(indazole)2] (Ln = Tb, Dy, and Lu), were synthesized using a monoanionic bidentate hexafluoroacetylacetone (hfaa(-)) and a neutral monodentate indazole ligand. The X-ray diffraction analyses of their single-crystals indicate that the complexes are mononuclear. The Eu complex is nonacoordinate and has a distorted monocapped square antiprismatic structure whereas the terbium and dysprosium complexes are octacoordinate and possess a trigonal bicapped prism geometry. The indazole units are involved in π-π stacking interaction and N-H···F hydrogen bonding with the fluorine atoms of hfaa(-). The photophysical studies of indazole and the complexes show that the triplet states are at the appropriate positions and make ligand-to-metal energy transfer process efficient. A strong protective shield is provided by the coordination of three hfaa(-) moieties (which have low frequency C-F vibrational oscillators), and two/three ancillary indazole ligands around these metal ions ascribe higher quantum yields and longer radiative life times (ΦEu = 69% ± 10, 989 ± 1 μs, ΦTb = 33% ± 10, 546 ± 1 μs, and ΦDy = 2.5% ± 10, 13.6 ± 1 μs) to these novel compounds. The emission from europium, terbium, and dysprosium are, respectively, red, green, and yellow. Finally, these compounds were used, as emitting layers, to fabricate electroluminescent devices of their respective colors. The best devices are found with the following structure: ITO/CuPc (15 nm)/[Eu complex]:CBP or [Tb complex]:CBP or [Dy complex]:CBP (80 nm)/BCP (25 nm)/AlQ (30 nm)/LiF (1 nm)/Al (100 nm), which indicates an improved EL performance for the Eu device over the Eu devices reported in the literature. The ligand, indazole, is a good sensitizer for trivalent europium, terbium, and dysprosium ions. It together with hfaa(-) plays an important role in fabricating OLEDs, especially

  2. Synthesis, structure and luminescence property of 2D lanthanide complexes with 3-fluorophthalate and oxalate

    SciTech Connect

    Cha, Yu-E; Li, Xia; Song, Shuang

    2012-12-15

    Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (Ln=Sm 1, Eu 2, Tb 3 and Dy 4; fpht=3-fluorophthalate and ox=oxalate) have been synthesized and structurally characterized by single crystal X-ray diffraction. The four complexes possess similar 2D framework structures constructed from Ln-fpht double-stranded helices and ox linkages. Complexes 2 and 3 display the characteristic emission {sup 5}D{sub 0}{yields}{sup 7}F{sub J} (J=0-4) transitions of Eu(III) ion and {sup 5}D{sub 4}{yields}{sup 7}F{sub J} (J=6-3) transitions of Tb(III) ion, respectively. The emission decay curves reveal a monoexponential behavior yielding the lifetime values of 0.266{+-}0.002 ms for 2 and 0.733{+-}0.002 ms for 3. The emission spectrum of 1 shows three weak bands corresponding to the characteristic emission {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 5/2}, {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 7/2} and {sup 4}G{sub 5/2}{yields}{sup 6}H{sub 9/2} transitions of Sm(III) ion. The emission spectrum of 4 displays a broad band centered at 438 nm, which comes from the {pi}{sup Low-Asterisk }-{pi} transition of the ligand. - Graphical abstract: Complexes [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate, ox=oxalate) possess 2D structures. Sm(III), Eu(III) and Tb(III) complexes show the characteristic fluorescent emission of the Ln(III). Dy(III) complex displays ligand-based luminescent behavior. Highlights: Black-Right-Pointing-Pointer [Ln{sub 2}(fpht){sub 2}(ox)(H{sub 2}O){sub 4}]{center_dot}H{sub 2}O (fpht=3-fluorophthalate; ox=oxalate) show 2D structures. Black-Right-Pointing-Pointer The 2D structures are constructed from Ln-fpht double-stranded helices and ox linkage. Black-Right-Pointing-Pointer The Sm(III), Eu(III) and Tb(III) complexes show the characteristic emission of the Ln(III) ions. Black-Right-Pointing-Pointer Dy(III) complex displays ligand-based luminescent behavior.

  3. 3,4,3-LI(1,2-HOPO): In Vitro Formation of Highly Stable Lanthanide Complexes Translates into Efficacious In Vivo Europium Decorporation

    SciTech Connect

    Sturzbecher-Hoehne, Manuel; Ng Pak Leung, Clara; Daleo, Anthony; Kullgren, Birgitta; Prigent, Anne-Laure; Shuh, David K.; Raymond, Kenneth N.; Abergel, Rebecca J.

    2011-07-13

    The spermine-based hydroxypyridonate octadentate chelator 3,4,3-LI(1,2-HOPO) was investigated for its ability to act as an antennae that sensitizes the emission of Sm{sup III}, Eu{sup III}, and Tb{sup III} in the Visible range (Φ{sub tot} = 0.2 - 7%) and the emission of Pr{sup III}, Nd{sup III}, Sm{sup III}, and Yb{sup III} in the Near Infra-Red range, with decay times varying from 1.78 μs to 805 μs at room temperature. The particular luminescence spectroscopic properties of these lanthanide complexes formed with 3,4,3-LI(1,2-HOPO) were used to characterize their respective solution thermodynamic stabilities as well as those of the corresponding La{sup III}, Gd{sup III}, Dy{sup III}, Ho{sup III}, Er{sup III}, Tm{sup III}, and Lu{sup III} complexes. The remarkably high affinity of 3,4,3-LI(1,2-HOPO) for lanthanide metal ions and the resulting high complex stabilities (pM values ranging from 17.2 for La{sup III} to 23.1 for Yb{sup III}) constitute a necessary but not sufficient criteria to consider this octadentate ligand an optimal candidate for in vivo metal decorporation. The in vivo lanthanide complex stability and decorporation capacity of the ligand were assessed, using the radioactive isotope {sup 152}Eu as a tracer in a rodent model, which provided a direct comparison with the in vitro thermodynamic results and demonstrated the great potential of 3,4,3-LI(1,2-HOPO) as a therapeutic metal chelating agent.

  4. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives

    NASA Astrophysics Data System (ADS)

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L = cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF = N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu3 + in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu3 + ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of 5D0 and triplet state contracts.

  5. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.

    PubMed

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts.

  6. Spectra, energy levels, and energy transition of lanthanide complexes with cinnamic acid and its derivatives.

    PubMed

    Zhou, Kaining; Feng, Zhongshan; Shen, Jun; Wu, Bing; Luo, Xiaobing; Jiang, Sha; Li, Li; Zhou, Xianju

    2016-04-01

    High resolution spectra and luminescent lifetimes of 6 europium(III)-cinnamic acid complex {[Eu2L6(DMF)(H2O)]·nDMF·H2O}m (L=cinnamic acid I, 4-methyl-cinnamic acid II, 4-chloro-cinnamic acid III, 4-methoxy-cinnamic acid IV, 4-hydroxy-cinnamic acid V, 4-nitro-cinnamic acid VI; DMF=N, N-dimethylformamide, C3H7NO) were recorded from 8 K to room temperature. The energy levels of Eu(3+) in these 6 complexes are obtained from the spectra analysis. It is found that the energy levels of the central Eu(3+) ions are influenced by the nephelauxetic effect, while the triplet state of ligand is lowered by the p-π conjugation effect of the para-substituted functional groups. The best energy matching between the ligand triplet state and the central ion excited state is found in complex I. While the other complexes show poorer matching because the gap of (5)D0 and triplet state contracts. PMID:26802538

  7. Complexing mechanism of the lanthanide cations Eu3+, Gd3+, and Tb3+ with 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (dota)-characterization of three successive complexing phases: study of the thermodynamic and structural properties of the complexes by potentiometry, luminescence spectroscopy, and EXAFS.

    PubMed

    Moreau, Juliette; Guillon, Emmanuel; Pierrard, Jean-Claude; Rimbault, Jean; Port, Marc; Aplincourt, Michel

    2004-10-11

    Complexation of the lanthanides Eu3+, Gd3+, and Tb3+ with 1,4,7,10-tetrakis(carboxymethyl)-1,4,7,10-tetraazacyclododecane (dota) has been studied in solution by using potentiometry, luminescence spectrometry, and EXAFS. Three series of successive complexes were characterized by at least two of these methods: the immediate [LnHn(dota)](n-1)+** and intermediate [LnHn(dota)](n-1)+* complexes with 0 complexes. The formation constants of the intermediate and final complexes were determined by using potentiometry. From the results, a complexation mechanism involving three steps has been proposed. In the [LnHn(dota)](n-1)+** complexes that are instantaneously formed, the lanthanide is bound to four oxygen atoms of the carboxylate groups and to five water molecules. These species evolve rapidly: the lanthanide moves into the macrocycle cavity, two new bonds are formed with two nitrogen atoms diametrically opposed in the tetraaza cycle and only three water molecules remain bound to the lanthanide in the [LnHn(dota)](n-1)+* (0 complexes, which appear after a two-day wait. These compounds are stable for about four days. After 4-8 weeks, a concerted rearrangement occurs which leads to the formation of thermodynamically stable [Ln(dota)]- complexes in which the lanthanide is bound to four nitrogen atoms, four carboxylate oxygen atoms, and one water molecule.

  8. Lanthanide triangles sandwiched by tetranuclear copper complexes afford a family of hendecanuclear heterometallic complexes [Ln(III)3Cu(II)8] (Ln = La-Lu): synthesis and magnetostructural studies.

    PubMed

    Iasco, Olga; Novitchi, Ghenadie; Jeanneau, Erwann; Luneau, Dominique

    2013-08-01

    Reaction in ethanol of 3-hydroxymethylen-5-methylsalicylaldoxime (H3L) with CuCl2·2H2O and LnCl3·xH2O [Ln = La (1), Ce (2), Pr (3), Nd (4), Eu (5), Gd (6), Tb (7), Dy (8), Er (9), Yb (10), Lu (11), Ho (12)] allowed the synthesis of a family of hendecanuclear heterometallic copper(II)-lanthanide(III) clusters with general formula [Ln(III)3Cu(II)8(HL)6(μ4-O)2Cl6(H2O)8]Cl3 (1-12). According to the single-crystal X-ray diffraction investigation, the complexes are isomorphous and crystallize in the trigonal R32 group. The hendecanuclear cluster is formed by two tetrahedral μ4-oxo {Cu4} clusters assembled by three lanthanide ions sandwiched in between. Along the family, the separation between the {Cu4} moieties increases linearly from Lu to La in good correlation with ionic radius of the lanthanide ions. A comparative analysis of the magnetic data for the lanthanum (1) and lutetium (11) compounds shows the presence of ferromagnetic and antiferromagnetic interactions within the μ4-oxo {Cu4} moieties. For the gadolinium (6) and terbium (7) compounds, the magnetic interactions between the lanthanide and the copper ions are found to be ferromagnetic. The dysprosium (8) compound exhibits single-molecule magnet behavior.

  9. Luminescent lanthanide complexes with 4-acetamidobenzoate: Synthesis, supramolecular assembly via hydrogen bonds, crystal structures and photoluminescence

    NASA Astrophysics Data System (ADS)

    Yin, Xia; Fan, Jun; Wang, Zhi Hong; Zheng, Sheng Run; Tan, Jing Bo; Zhang, Wei Guang

    2011-07-01

    Four new luminescent complexes, namely, [Eu(aba) 2(NO 3)(C 2H 5OH) 2] ( 1), [Eu(aba) 3(H 2O) 2]·0.5 (4, 4'-bpy)·2H 2O ( 2), [Eu 2(aba) 4(2, 2'-bpy) 2(NO 3) 2]·4H 2O ( 3) and [Tb 2(aba) 4(phen) 2(NO 3) 2]·2C 2H 5OH ( 4) were obtained by treating Ln(NO 3) 3·6H 2O and 4-acetamidobenzoic acid (Haba) with different coligands (4, 4'-bpy=4, 4'-bipyridine, 2, 2'-bpy=2, 2'-bipyridine, and phen=1, 10-phenanthroline). They exhibit 1D chains ( 1- 2) and dimeric structures ( 3- 4), respectively. This structural variation is mainly attributed to the change of coligands and various coordination modes of aba molecules. Moreover, the coordination units are further connected via hydrogen bonds to form 2D even 3D supramolecular networks. These complexes show characteristic emissions in the visible region at room temperature. In addition, thermal behaviors of four complexes have been investigated under air atmosphere. The relationship between the structures and physical properties has been discussed.

  10. Syntheses, structure, magnetic and thermodynamics property of novel lanthanide complexes with nitronyl nitroxide radical

    NASA Astrophysics Data System (ADS)

    Song, Mei-Ying; Hou, Yi-Fang; Wen, Long-Mei; Wang, Shu-Ping; Yang, Shu-Tao; Zhang, Jian-Jun; Geng, Li-Na; Shi, Shi-Kao

    2016-03-01

    Four new nitronyl nitroxide radical-Ln(III) complexes, Ln(hfac)3(NITPhSCF3)2 (Ln(III) = Sm(1), Gd(2), Tb(3), Dy(4); NITPhSCF3 = 2-(4-trifluoromethylthiophenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl- 3-oxide; hfac = hexafluoroacetylacetonate), have been synthesized and characterized. They are isostructural, which show mononuclear tri-spin structures. The central Ln(III) ion is eight-coordinated by three hfac anions and two NITPhSCF3 molecules. Direct-current magnetic study shows that there exist ferromagnetic interactions between Gd(III) ion and radicals (NITPhSCF3) with JGd-Rad = 1.61 cm-1, and antiferromagnetic interactions between radicals with JRad-Rad = -2.83 cm-1 in complex 2. The magnetic analysis with the rough approximate model show that a ferromagnetic coupling exists between Tb(III) and radical in 3, while a antiferromagnetic coupling between Dy(III) and radical in 4. The thermodynamics properties of four complexes were studied with differential scanning calorimetry (DSC), such as heat capacity, thermodynamic functions (HT-H298.15K), (ST-S298.15K), and (GT-G298.15K).

  11. Complexation of Sn{sub 2}Se{sub 6} with lanthanide(III) centers influenced by ethylene polyamines: Solvothermal syntheses, crystal structures, and optical properties of lanthanide selenidostannates

    SciTech Connect

    Tang, Chunying; Wang, Fang; Chen, Ruihong; Jiang, Wenqing; Zhang, Yong; Jia, Dingxian

    2013-08-15

    Lanthanide selenidostannates (H{sub 3}O){sub n}[Ce(tepa)(μ-1κ{sup 2}:2κ{sup 2}-Sn{sub 2}Se{sub 6})]{sub n} (1), [(Yb(tepa)(μ-OH)){sub 2}(μ-1κ:2κ-Sn{sub 2}Se{sub 6})]{sub n}·nH{sub 2}O (2), [Htrien]{sub 2}[(Ln(trien)(tren)){sub 2}(μ-1κ:2κ-Sn{sub 2}Se{sub 6})][Sn{sub 2}Se{sub 6}] (Ln=Ce(3), Nd(4)) and [(Yb(dien){sub 2}){sub 2}(μ-OH){sub 2}]Sn{sub 2}Se{sub 6} (5) were solvothermally prepared in different ethylene polyamines. The Sn{sub 2}Se{sub 6} unit connects [Ce(tepa)]{sup 3+} and [(Yb(tepa)(μ-OH)){sub 2}]{sup 4+} fragments with tetradentate μ-1κ{sup 2}Se{sup 1},Se{sup 2}:2κ{sup 2}Se{sup 5},Se{sup 6} and bidentate μ-1κSe{sup 1}:2κSe{sup 5} bridging coordination modes in tepa, to form polymers 1 and 2, respectively. It joins two [Ln(trien)(tren)]{sup 3+} fragments as a μ-1κSe{sup 1}:2κSe{sup 5} ligand to form binuclear complexes 3 and 4 in trien. Unlike the Sn{sub 2}Se{sub 6} units in 1–4 that bind with Ln(III) centers as Se-donor ligands, the Sn{sub 2}Se{sub 6} unit in 5 exists as a discrete ion. The syntheses of 1–5 show that the ethylene polyamines play an important role in the complexation of Sn{sub 2}Se{sub 6} ligand with Ln(III) centers. Compounds 1–5 exhibit optical band gaps in the range of 2.09–2.42 eV, which are influenced by the complexation of Sn{sub 2}Se{sub 6} with Ln(III) centers. - Graphical abstract: New lanthanide complexes concerning the Sn{sub 2}Se{sub 6} ligand were solvothermally prepared, and the effect of ethylene polyamines on the complexation of Sn{sub 2}Se{sub 6} with Ln(III) centers are observed. Highlights: • Lanthanide complexes concerning the selenidostannates have been solvothermally prepared in different ethylene polyamines. • A tetradentate μ-1κ{sup 2}Se{sup 1},Se{sup 2}:2κ{sup 2}Se{sup 5},Se{sup 6} and a bidentate μ-1κSe{sup 1}:2κSe{sup 5} bridging coordination modes for the Sn{sub 2}Se{sub 6} ligand is obtained. • The complexation of the Sn{sub 2}Se{sub 6} ligand with Ln(III) centers are

  12. Covalent lanthanide(III) macrocyclic complexes: the bonding nature and optical properties of a promising single antenna molecule.

    PubMed

    Rabanal-León, Walter A; Páez-Hernández, Dayán; Arratia-Pérez, Ramiro

    2014-12-21

    The present work is focused on the elucidation of the electronic structure, bonding nature and optical properties of a series of low symmetry (C2) coordination compounds of type [Ln(III)HAM](3+), where "Ln(III)" are the trivalent lanthanide ions: La(3+), Ce(3+), Eu(3+) and Lu(3+), while "HAM" is the neutral six-nitrogen donor macrocyclic ligand [C22N6H26]. This systematic study has been performed in the framework of the Relativistic Density Functional Theory (R-DFT) and also using a multi-reference approach via the Complete Active Space (CAS) wavefunction treatment with the aim of analyzing their ground state and excited state electronic structures as well as electronic correlation. Furthermore, the use of the energy decomposition scheme proposed by Morokuma-Ziegler and the electron localization function (ELF) allows us to characterize the bonding between the lanthanide ions and the macrocyclic ligand, obtaining as a result a dative-covalent interaction. Due to a great deal of lanthanide optical properties and their technological applications, the absorption spectra of this set of coordination compounds were calculated using the time-dependent density functional theory (TD-DFT), where the presence of the intense Ligand to Metal Charge Transfer (LMCT) bands in the ultraviolet and visible region and the inherent f-f electronic transitions in the Near-Infra Red (NIR) region for some lanthanide ions allow us to propose these systems as "single antenna molecules" with potential applications in NIR technologies.

  13. Features of the complexation of octadecane-2,4-dione and lanthanide ions in Langmuir monolayers

    NASA Astrophysics Data System (ADS)

    Sokolov, M. E.; Repina, I. N.; Raitman, O. A.; Kolokolov, F. A.; Panyushkin, V. T.

    2016-05-01

    Monolayers of octadecane-2,4-dione on the surfaces of EuCl3 and TbCl3 solutions in the concentration range of 1 × 10-4 to 5 × 10-3 M at pH 5.8 are studied. It is found that the limiting area of octadecane-2,4-dione molecule in a monolayer dependence on Eu3+ and Tb3+ concentration is of extreme nature. The formation of complex compounds in the ligand monolayer is postulated, and structures are proposed for these compounds at different concentrations of metal ions.

  14. Induced circularly polarized luminescence arising from anion or protein binding to racemic emissive lanthanide complexes

    NASA Astrophysics Data System (ADS)

    Carr, Rachel; Puckrin, Robert; McMahon, Brian K.; Pal, Robert; Parker, David; Pålsson, Lars-Olof

    2014-06-01

    A circularly polarized luminescence (CPL) spectrometer has been built and used to study the binding interaction of lactate and four different proteins with racemic EuIII and TbIII complexes in aqueous solution. Lactate binding gives rise to strong induced CPL spectra, and the observed emission dissymmetry factors vary linearly with enantiomeric composition. Particularly strong induced TbIII CPL also characterizes the binding interaction of alpha-1-acid glycoprotein with a dissociation constant, Kd, of 2.5 μM.

  15. Exploring tight junction alteration using double fluorescent probe combination of lanthanide complex with gold nanoclusters

    PubMed Central

    Wang, Xinyi; Wang, Na; Yuan, Lan; Li, Na; Wang, Junxia; Yang, Xiaoda

    2016-01-01

    Tight junctions play a key role in restricting or regulating passage of liquids, ions and large solutes through various biological barriers by the paracellular route. Changes in paracellular permeation indicate alteration of the tight junction. However, it is very difficult to obtain the structural change information by measuring paracellular flux based on transepithelial electrical resistance or using fluorescein-labeled dextrans. Here we show that the BSA and GSH stabilized gold nanoclusters exhibit marginal cytotoxicity and pass through the MDCK monolayer exclusively through the paracellular pathway. We propose a double fluorescence probe strategy, the combination of a proven paracellular indicator (europium complex) with fluorescent gold nanoclusters. We calculate changes of structural parameters in tight junctions based on determination of the diffusion coefficients of the probes. Two different types of tight junction openers are used to validate our strategy. Results show that EDTA disrupts tight junction structures and induces large and smooth paracellular pore paths with an average radius of 17 nm, but vanadyl complexes induce paths with the radius of 6 nm. The work suggests that the double fluorescence probe strategy is a useful and convenient approach for in vitro investigation of tight junction structural alternations caused by pharmacological or pathological events. PMID:27574102

  16. Exploring tight junction alteration using double fluorescent probe combination of lanthanide complex with gold nanoclusters.

    PubMed

    Wang, Xinyi; Wang, Na; Yuan, Lan; Li, Na; Wang, Junxia; Yang, Xiaoda

    2016-01-01

    Tight junctions play a key role in restricting or regulating passage of liquids, ions and large solutes through various biological barriers by the paracellular route. Changes in paracellular permeation indicate alteration of the tight junction. However, it is very difficult to obtain the structural change information by measuring paracellular flux based on transepithelial electrical resistance or using fluorescein-labeled dextrans. Here we show that the BSA and GSH stabilized gold nanoclusters exhibit marginal cytotoxicity and pass through the MDCK monolayer exclusively through the paracellular pathway. We propose a double fluorescence probe strategy, the combination of a proven paracellular indicator (europium complex) with fluorescent gold nanoclusters. We calculate changes of structural parameters in tight junctions based on determination of the diffusion coefficients of the probes. Two different types of tight junction openers are used to validate our strategy. Results show that EDTA disrupts tight junction structures and induces large and smooth paracellular pore paths with an average radius of 17 nm, but vanadyl complexes induce paths with the radius of 6 nm. The work suggests that the double fluorescence probe strategy is a useful and convenient approach for in vitro investigation of tight junction structural alternations caused by pharmacological or pathological events. PMID:27574102

  17. Exploring tight junction alteration using double fluorescent probe combination of lanthanide complex with gold nanoclusters

    NASA Astrophysics Data System (ADS)

    Wang, Xinyi; Wang, Na; Yuan, Lan; Li, Na; Wang, Junxia; Yang, Xiaoda

    2016-08-01

    Tight junctions play a key role in restricting or regulating passage of liquids, ions and large solutes through various biological barriers by the paracellular route. Changes in paracellular permeation indicate alteration of the tight junction. However, it is very difficult to obtain the structural change information by measuring paracellular flux based on transepithelial electrical resistance or using fluorescein-labeled dextrans. Here we show that the BSA and GSH stabilized gold nanoclusters exhibit marginal cytotoxicity and pass through the MDCK monolayer exclusively through the paracellular pathway. We propose a double fluorescence probe strategy, the combination of a proven paracellular indicator (europium complex) with fluorescent gold nanoclusters. We calculate changes of structural parameters in tight junctions based on determination of the diffusion coefficients of the probes. Two different types of tight junction openers are used to validate our strategy. Results show that EDTA disrupts tight junction structures and induces large and smooth paracellular pore paths with an average radius of 17 nm, but vanadyl complexes induce paths with the radius of 6 nm. The work suggests that the double fluorescence probe strategy is a useful and convenient approach for in vitro investigation of tight junction structural alternations caused by pharmacological or pathological events.

  18. Rational Design of a Lanthanide-Based Complex Featuring Different Single-Molecule Magnets.

    PubMed

    Pointillart, F; Guizouarn, T; Lefeuvre, B; Golhen, S; Cador, O; Ouahab, L

    2015-11-16

    The rational synthesis of the 2-{1-methylpyridine-N-oxide-4,5-[4,5-bis(propylthio)tetrathiafulvalenyl]-1H-benzimidazol-2-yl}pyridine ligand (L) is described. It led to the tetranuclear complex [Dy4(tta)12(L)2] (Dy-Dy2-Dy) after coordination reaction with the precursor Dy(tta)3⋅2 H2O (tta(-) = 2-thenoyltrifluoroacetonate). The X-ray structure of Dy-Dy2-Dy can be described as two terminal mononuclear units bridged by a central antiferromagnetically coupled dinuclear complex. The terminal N2O6 and central O8 environments are described as distorted square antiprisms. The ac magnetism measurements revealed a strong out-of-phase signal of the magnetic susceptibility with two distinct sets of data. The high- and low-frequency components were attributed to the two terminal mononuclear single-molecule magnets (SMMs) and the central dinuclear SMM, respectively. A magnetic hysteresis loop was detected at very low temperature. From both structural and magnetic points of view, the tetranuclear SMM Dy-Dy2-Dy is a self-assembly of two known mononuclear SMMs bridged by a known dinuclear SMM.

  19. An improved thermodynamic model for the complexation of trivalent actinides and lanthanide with oxalic acid valid to high ionic strength.

    DOE PAGES

    Xiong, Yongliang; Thakur, Punam; Borkowski, Marian

    2015-07-30

    The dissociation constants of oxalic acid (Ox), and the stability constants of Am3+, Cm3+ and Eu3+ with Ox2– have been determined at 25 °C, over a range of concentration varying from 0.1 to 6.60 m NaClO4 using potentiometric titration and extraction techniques, respectively. The experimental data support the formation of complexes, M(Ox)n3 – 2n, where (M = Am3+, Cm3+ and Eu3+ and n = 1 and 2). The dissociation constant and the stability constant values measured as a function of NaClO4 concentration were used to estimate the Pitzer parameters for the respective interactions of Am3+, Cm3+ and Eu3+ with Ox.more » Furthermore, the stability constants data of Am3+ –Ox measured in NaClO4 and in NaCl solutions from the literature were simultaneously fitted in order to refine the existing actinide–oxalate complexation model that can be used universally in the safety assessment of radioactive waste disposal. The thermodynamic stability constant: log β0101 = 6.30 ± 0.06 and log β0102 = 10.84 ± 0.06 for Am3+ was obtained by simultaneously fitting data in NaCl and NaClO4 media. Additionally, log β0101 = 6.72 ± 0.08 and log β0102 = 11.05 ± 0.09 for the Cm3+ and log β0101 = 6.67 ± 0.08 and log β0102 = 11.15 ± 0.09 for the Eu3+ were calculated by extrapolation of data to zero ionic strength in NaClO4 medium only. For all stability constants, the Pitzer model gives an excellent representation of the data using interaction parameters β(0), β(1), and CΦ determined in this work. The thermodynamic model developed in this work will be useful in accurately modeling the potential solubility of trivalent actinides and early lanthanides to ionic strength of 6.60 m in low temperature environments in the presence of Ox. Furthermore, the work is also applicable to the accurate modeling transport of rare earth elements in various environments under the surface conditions.« less

  20. Substituent effects on fluoride binding by lanthanide complexes of DOTA-tetraamides.

    PubMed

    Blackburn, Octavia A; Routledge, Jack D; Jennings, Laura B; Rees, Nicholas H; Kenwright, Alan M; Beer, Paul D; Faulkner, Stephen

    2016-02-21

    Fluoride binding by a series of europium and ytterbium complexes of DOTA-tetraamide ligands derived from primary, secondary and tertiary amides has been studied by NMR and luminescence spectroscopies. In all the systems studied, fluoride binding results in a change in the nature of the magnetic anisotropy at the metal centre from an easy axis, to an easy plane anisotropy. This results in reversal of the peaks in the NMR spectra, and in changes to the fine structure of the luminescence spectra. Furthermore, changes to the periphery of the binding cavity are implicated in determining the affinity constant for fluoride. There are clear differences in the entropic contribution to the free energy of activation between systems with benzylic amides and those with methylamides. PMID:26765788

  1. Failure of ESI Spectra to Represent Metal-Complex Solution Composition: A Study of Lanthanide-Carboxylate Complexes

    SciTech Connect

    McDonald, Luther W.; Campbell, James A.; Clark, Sue B.

    2014-01-21

    Electrospray ionization - mass spectrometry (ESI-MS) was used for the characterization of uranyl complexed to tributyl phosphate (TBP) and dibutyl phosphate (DBP). The stoichiometry of uranyl with TBP and DBP was determined, and the gas phase speciation was found to be dependent on the cone voltage applied to induce fragmentation on the gas phase complexes. To quantitatively compare the gas phase distribution of species to solution, apparent stability constants were calculated. With a cone voltage of 80V, the apparent stability constants for the complexes UO2(NO3)2•2TBP, UO2(NO3)2(H2O)•2TBP, and UO2(DBP)+ were determined. With a lower cone voltage applied, larger complexes were observed and stability constants for the complexes UO2(NO3)2•3TBP and UO2(DBP)42- were determined.

  2. Preparation of Lanthanide-Polymer Composite Material via Click Chemistry.

    PubMed

    Chen, Bin; Wen, Guian; Wu, Jiajie; Feng, Jiachun

    2015-10-01

    Covalently attaching lanthanide complexes to the polymer backbone can effectively reduce the clustering of lanthanides and thus become an important strategy to fully unleash their potential. In this Communication, a metal-free click reaction is used for the first time to link a lanthanide complex to the polymer matrix. A diene-bearing copolymer with anthracenylmethyl methacrylate as a monomer and a dienophile-bearing lanthanide complex with 5-maleimido-1,10-phenanthroline as the second ligand are synthesized and coupled together through a Diels-Alder cycloaddition (DA). A comparative investigation demonstrates that the composite material prepared by DA click reaction shows the highest quantum yields in the same lanthanide concentration as compared to materials prepared by widely used "directly doping" and "in situ coordinating lanthanide ions with macromolecular ligand" approaches. This work suggests that the "metal-free" DA click reaction can be a promising tool in the synthesis of high efficient lanthanide functionalized polymeric materials.

  3. Crystallization of the pneumococcal autolysin LytC: in-house phasing using novel lanthanide complexes

    PubMed Central

    Pérez-Dorado, Inmaculada; Sanles, Reyes; González, Ana; García, Pedro; García, José L.; Martínez-Ripoll, Martín; Hermoso, Juan A.

    2010-01-01

    LytC, one of the major autolysins from the human pathogen Streptococcus pneumoniae, has been crystallized as needles by the hanging-drop technique using 10%(w/v) PEG 3350 as precipitant and 10 mM HEPES pH 7.5. LytC crystals were quickly soaked in mother liquor containing 2 mM of the complex Gd-HPDO3A to produce derivatized crystals (LytCGd-HPDO3A). Both native LytC and isomorphous LytCGd-HPDO3A crystals were flash-cooled in a nitrogen flow at 120 K prior to X-ray data collection using an in-house Enraf–Nonius rotating-anode generator (λ = 1.5418 Å) and a MAR345 imaging-plate detector. In both cases, good-quality diffraction patterns were obtained at high resolution. LytCGd-HPDO3A crystals allowed the collection of a SAD X-ray data set to 2.6 Å resolution indexed in terms of a P21 monoclinic unit cell with parameters a = 59.37, b = 67.16, c = 78.85 Å, β = 105.69°. The anomalous Patterson map allowed the identification of one heavy-atom binding site, which was sufficient for the calculation of an interpretable anomalous map at 2.6 Å resolution. PMID:20383019

  4. Gold nanoparticle assemblies stabilized by bis(phthalocyaninato)lanthanide(III) complexes through van der Waals interactions

    PubMed Central

    Noda, Yuki; Noro, Shin-ichiro; Akutagawa, Tomoyuki; Nakamura, Takayoshi

    2014-01-01

    Gold nanoparticle assemblies possess diverse application potential, ranging from industrial nanotechnology to medical biotechnology. Because the structures and properties of assemblies are directly affected by the stabilization mechanism between the organic molecules serving as protecting ligands and the gold nanoparticle surface, it is crucial to find and investigate new stabilization mechanisms. Here, we report that π-conjugated phthalocyanine rings can serve as stabilizing ligands for gold nanoparticles. Bis(phthalocyaninato)lutetium(III) (LuPc2) or bis(phthalocyaninato)terbium(III) (TbPc2), even though complex, do not have specific binding units and stabilize gold nanoparticles through van der Waals interaction between parallel adsorbed phthalocyanine ligands and the gold nanoparticle surface. AC magnetic measurements and the electron-transport properties of the assemblies give direct evidence that the phthalocyanines are isolated from each other. Each nanoparticle shows weak electronic coupling despite the short internanoparticle distance (~1 nm), suggesting Efros–Shklovskii-type variable-range hopping and collective single-electron tunnelling behaviours. PMID:24441566

  5. Gold nanoparticle assemblies stabilized by bis(phthalocyaninato)lanthanide(III) complexes through van der Waals interactions

    NASA Astrophysics Data System (ADS)

    Noda, Yuki; Noro, Shin-Ichiro; Akutagawa, Tomoyuki; Nakamura, Takayoshi

    2014-01-01

    Gold nanoparticle assemblies possess diverse application potential, ranging from industrial nanotechnology to medical biotechnology. Because the structures and properties of assemblies are directly affected by the stabilization mechanism between the organic molecules serving as protecting ligands and the gold nanoparticle surface, it is crucial to find and investigate new stabilization mechanisms. Here, we report that π-conjugated phthalocyanine rings can serve as stabilizing ligands for gold nanoparticles. Bis(phthalocyaninato)lutetium(III) (LuPc2) or bis(phthalocyaninato)terbium(III) (TbPc2), even though complex, do not have specific binding units and stabilize gold nanoparticles through van der Waals interaction between parallel adsorbed phthalocyanine ligands and the gold nanoparticle surface. AC magnetic measurements and the electron-transport properties of the assemblies give direct evidence that the phthalocyanines are isolated from each other. Each nanoparticle shows weak electronic coupling despite the short internanoparticle distance (~1 nm), suggesting Efros-Shklovskii-type variable-range hopping and collective single-electron tunnelling behaviours.

  6. Hybrid materials of MCM-41 functionalized by lanthanide (Tb{sup 3+}, Eu{sup 3+}) complexes of modified meta-methylbenzoic acid: Covalently bonded assembly and photoluminescence

    SciTech Connect

    Li Ying; Yan Bing

    2008-05-15

    Novel organic-inorganic mesoporous hybrid materials were synthesized by linking lanthanide (Tb{sup 3+}, Eu{sup 3+}) complexes to the mesoporous MCM-41 through the modified meta-methylbenzoic acid (MMBA-Si) using co-condensation method in the presence of the cetyltrimethylammonium bromide (CTAB) surfactant as template. The luminescence properties of these resulting materials (denoted as Ln-MMBA-MCM-41, Ln=Tb, Eu) were characterized in detail, and the results reveal that luminescent mesoporous materials have high surface area, uniformity in the ordered mesoporous structure. Moreover, the mesoporous material covalently bonded Tb{sup 3+} complex (Tb-MMBA-MCM-41) exhibits the stronger characteristic emission of Tb{sup 3+} and longer lifetime than Eu-MMBA-MCM-41 due to the triplet state energy of organic legend MMBA-Si matches with the emissive energy level of Tb{sup 3+} very well. - Graphical abstract: Novel organic-inorganic mesoporous luminescent materials were synthesized by linking lanthanide (Tb{sup 3+}, Eu{sup 3+}) complexes to covalently bond the functionalized ordered mesoporous MCM-41 with modified meta-methylbenzoic acid (MMBA)-Si by co-condensation of tetraethoxysilane (TEOS) in the presence of the cetyltrimethylammonium bromide (CTAB) surfactant as template.

  7. Syntheses, characterization, biological activity and fluorescence properties of bis-(salicylaldehyde)-1,3-propylenediimine Schiff base ligand and its lanthanide complexes.

    PubMed

    Taha, Ziyad A; Ajlouni, Abdulaziz M; Al-Hassan, Khader A; Hijazi, Ahmed K; Faiq, Ari B

    2011-10-15

    Eight new lanthanide metal complexes [LnL(NO(3))(2)]NO(3) {Ln(III) = Nd, Dy, Sm, Pr, Gd, Tb, La and Er, L = bis-(salicyladehyde)-1,3-propylenediimine Schiff base ligand} were prepared. These complexes were characterized by elemental analysis, thermogravimetric analysis (TGA), molar conductivity measurements and spectral studies ((1)H NMR, FT-IR, UV-vis, and luminescence). The Schiff base ligand coordinates to Ln(III) ion in a tetra-dentate manner through the phenolic oxygen and azomethine nitrogen atoms. The coordination number of eight is achieved by involving two bi-dentate nitrate groups in the coordination sphere. Sm, Tb and Dy complexes exhibit the characteristic luminescence emissions of the central metal ions attributed to efficient energy transfer from the ligand to the metal center. Most of the complexes exhibit antibacterial activity against a number of pathogenic bacteria.

  8. Analysis of multinuclear lanthanide-induced shifts. 4. Some consequences of the lanthanide contraction

    NASA Astrophysics Data System (ADS)

    Peters, Joop A.

    The effects of the lanthanide contraction on lanthanide-induced shifts are estimated using simulated structures for a set of lanthanide chelates. The variations of the Ln-donor distances cause small conformational changes in the coordination polyhedron of the Ln(III) cation, and the induced pseudocontact shifts for a series of Ln complexes vary gradually going from La(III) to Lu(III). As a result of data manipulation these gradual variations may sometimes show up as an abrupt break in the middle of the lanthanide series.

  9. Macrocyclic lanthanide complexes as artificial nucleases and ribonucleases: effects of pH, metal ionic radii, number of coordinated water molecules, charge, and concentrations of the metal complexes.

    PubMed

    Chang, C Allen; Wu, Bo Hong; Kuan, Bu Yuan

    2005-09-19

    We have been interested in the design, synthesis, and characterization of artificial nucleases and ribonucleases by employing macrocyclic lanthanide complexes because their high thermodynamic stability, low kinetic lability, high coordination number, and charge density (Lewis acidity) allow more design flexibility and stability. In this paper, we report the study of the use of the europium(III) complex, EuDO2A+ (DO2A is 1,7-dicarboxymethyl-1,4,7,10-tetraazacyclododecane) and other lanthanide complexes (i.e., LaDO2A+, YbDO2A+, EuK21DA+, EuEDDA+, and EuHEDTA where K21DA is 1,7-diaza-4,10,13-trioxacyclopentadecane-N,N'-diacetic acid, EDDA is ethylenediamine-N,N'-diacetic acid, and HEDTA is N-hydroxyethyl-ethylenediamine-N,N',N'-triacetic acid), as potential catalysts for the hydrolysis of the phosphodiester bond of BNPP (sodium bis(4-nitrophenyl)-phosphate). For the pH range 7.0-11.0 studied, EuDO2A+ promotes BNPP hydrolysis with the quickest rates among LaDO2A+, EuDO2A+, and YbDO2A+. This indicates that charge density is not the only factor affecting the reaction rates. Among the four complexes, EuDO2A+, EuK21DA+, EuEDDA+, and EuHEDTA, with their respective number of inner-sphere coordinated water molecules three, two, five, and three, EuEDDA+, with the greatest number of inner-sphere coordinated water molecules and a positive charge, promotes BNPP hydrolysis more efficiently at pH below 8.4, and the observed rate trend is EuEDDA+ > EuDO2A+ > EuK21DA+ > EuHEDTA. At pH > 8.4, the EuEDDA+ solution becomes misty and precipitates form. At pH 11.0, the hydrolysis rate of BNPP in the presence of EuDO2A+ is 100 times faster than that of EuHEDTA, presumably because the positively charged EuDO2A+ is more favorable for binding with the negatively charged phosphodiester compounds. The logarithmic hydrolysis constants (pKh) were determined, and are reported in the parentheses, by fitting the kinetic k(obs) data vs pH for EuDO2A+ (8.4), LaDO2A+ (8.4), YbDO2A+ (9.4), EuK21DA+ (7

  10. The syntheses, structures and properties of three new lanthanoid thioarsenates: the only example of thioarsenate acting as a ligand to a lanthanide complex.

    PubMed

    Zhou, Jian; Liu, Xing; Li, Rong; An, Litao; Hu, Feilong; Chen, Rong; Wei, Yuanchun

    2013-08-21

    Three new lanthanoid thioarsenates [Eu(en)3(η²-AsS₄)] (1, en = ethylenediamine), [Er(teta)(en)(η²-AsS₄)] (2, teta = triethylenetetramine) and [La₂(tepa)₂(μ-η¹,η³-AsS₃)₂] (3, tepa = tetraethylenepentamine) have been solvothermally synthesized and structurally characterized. In compounds 1 and 2, the tetrathioarsenate [AsS₄]³⁻ anions act as η²-AsS₄ chelating ligands to the lanthanide complexes [Eu(en)₃]³⁺/[Er(teta)(en)]³⁺, leading to neutral molecules [Eu(en)₃(η²-AsS₄)]/[Er(teta)(en)(η²-AsS₄)], whereas the [AsS₃]³⁻ anion in compound 3 acts as a μ-η¹,η³-AsS₃ tetradentate bridging ligand to link [La(tepa)]³⁺ ions into neutral centrosymmetric [La₂(tepa)₂(μ-η¹,η³-AsS₃)₂] moieties, where a new coordination mode of μ-η¹,η³-AsS₃ is observed for the [AsS₃]³⁻ ligand. Compounds 1-3 are the only examples of solvothermally synthesized thioarsenates where the [AsS₄]³⁻/[AsS₃]³⁻ anions act as ligands in the lanthanide complex. Compound 1 exhibits a fluorescence emission at room temperature. Density functional theory calculations for compounds 2 and 3 also have been performed, and the absorption edges of compounds 1-3 have been investigated by UV-vis spectroscopy.

  11. Solid-state and solution-state coordination chemistry of lanthanide(III) complexes with (pyrazol-1-yl)acetic acid.

    PubMed

    Chen, Xiao-Yan; Goff, George S; Scott, Brian L; Janicke, Michael T; Runde, Wolfgang

    2013-03-18

    As a precursor of carboxyl-functionalized task-specific ionic liquids (TSILs) for f-element separations, (pyrazol-1-yl)acetic acid (L) can be deprotonated as a functionalized pyrazolate anion to coordinate with hard metal cations. However, the coordination chemistry of L with f-elements remains unexplored. We reacted L with lanthanides in aqueous solution at pH = 5 and synthesized four lanthanide complexes of general formula [Ln(L)3(H2O)2]·nH2O (1, Ln = La, n = 2; 2, Ln = Ce, n = 2; 3, Ln = Pr, n = 2; 4, Ln = Nd, n = 1). All complexes were characterized by single crystal X-ray diffraction analysis revealing one-dimensional chain formations. Two distinct crystallographic structures are governed by the different coordination modes of carboxylate groups in L: terminal bidentate and bridging tridentate (1-3); terminal bidentate, bridging bidentate, and tridentate coordination in 4. Comparison of the solid state UV-vis-NIR diffuse reflectance spectra with solution state UV-vis-NIR spectra suggests a different species in solution and solid state. The different coordination in solid state and solution was verified by distinctive (13)C NMR signals of the carboxylate groups in the solid state NMR.

  12. Slow relaxation of the magnetization in an Isostructural series of Zinc-lanthanide complexes: an integrated EPR and AC susceptibility study

    NASA Astrophysics Data System (ADS)

    Amjad, Asma; Madalan, Augustin; Andruh, Marius; Caneschi, Andrea; Sorace, Lorenzo; University of Bucharest, Faculty of Chemistry, Inorganic Chemistry Laboratory, Bucharest, Romania Collaboration

    2015-03-01

    Lanthanide based molecular complexes have shown potential to behave as single molecule magnets proficient to function above cryogenic temperatures. In this work we explore the dynamics of one such family, [Zn(LH)2Ln](NO3)3 .6H2O - (Ln = Nd3+, Dy3+, Tb3+, Ho3+, Er3+, Yb3+) . The series has a single lanthanide ion as a magnetic center in a low symmetry environment; the dynamics and energy landscape of the series is explored using X-band EPR, AC and DC susceptibility over a range of temperature, field and frequency. DC magnetic data show χT value consistent with expected behavior. EPR spectra for Er3+ and Yb3+ complexes shows EPR spectra typical for easy-plane and quasi-isotropic systems respectively, thus explaining the lack of out of phase susceptibility even in an external applied filed. However, Dy3+ derivative show slow relaxation of the magnetization in zero field up to 15 K and is, accordingly EPR silent.

  13. Method bacterial endospore quantification using lanthanide dipicolinate luminescence

    NASA Technical Reports Server (NTRS)

    Ponce, Adrian (Inventor); Venkateswaran, Kasthuri J. (Inventor); Kirby, James Patrick (Inventor)

    2007-01-01

    A lanthanide is combined with a medium to be tested for endospores. The dipicolinic acid released from the endospores binds the lanthanides, which have distinctive emission (i.e., luminescence) spectra, and are detected using photoluminescence. The concentration of spores is determined by preparing a calibration curve generated from photoluminescence spectra of lanthanide complex mixed with spores of a known concentration. A lanthanide complex is used as the analysis reagent, and is comprised of lanthanide ions bound to multidentate ligands that increase the dipicolinic acid binding constant through a cooperative binding effect with respect to lanthanide chloride. The resulting combined effect of increasing the binding constant and eliminating coordinated water and multiple equilibria increase the sensitivity of the endospore assay by an estimated three to four orders of magnitude over prior art of endospore detection based on lanthanide luminescence.

  14. New Family of Lanthanide-Based Complexes with Different Scorpionate-Type Ligands: A Rare Case Where Dysprosium and Ytterbium Analogues Display Single-Ion-Magnet Behavior.

    PubMed

    Lannes, Anthony; Luneau, Dominique

    2015-07-20

    A new family of lanthanide complexes [Ln(Tpz)2Bpz]·xCH2Cl2 (Ln = Gd, Tb, Dy, Ho, x = 0.5; Ln = Yb, x = 1; Tpz = hydrotris(pyrazolyl)borate; Bpz = dihydrobis(pyrazolyl)borate) has been synthesized. Those complexes have been characterized by single-crystal X-ray diffraction, and the magnetic properties have been investigated. Both dysprosium and ytterbium analogues display single-ion-magnet behavior, despite the difference in their spatial distribution of 4f electronic charges. Theoretical calculations with crystal field parameters have been carried out to gain better insight of the relaxation pathways that may be involved in those two complexes. PMID:26132295

  15. Coordination Complexes of Decamethylytterbocene with4,4'-Disubstituted Bipyridines: An Experimental Study of Spin Coupling inLanthanide Complexes

    SciTech Connect

    Walter, Marc D.; Berg, David J.; Andersen, Richard A.

    2005-12-08

    The paramagnetic 1:1 coordination complexes of (C5Me5)2Ybwith a series of 4,4'-disubstituted bipyridines, bipy-X, where X is Me,tert-Bu, OMe, Ph, CO2Me, and CO2Et have been prepared. All of thecomplexes are paramagnetic and the values of the magnetic susceptibilityas a function of temperature show that these values are less thanexpected for the cation, [(C5Me5)2Yb(III)(bipy-X)]+, which have beenisolated as the cation-anion ion-pairs[(C5Me5)2Yb(III)(bipy-X)]+[(C5Me5)2YbI2]f fnfn where X is CO2Et, OMe andMe. The 1H NMR chemical shifts (293 K) for the methine resonances locatedat the 6,6' site in the bipy-X ring show a linear relationship with thevalues of chiT (300 K) for the neutral complexes which illustrates thatthe molecular behavior does not depend upon the phase with one exception,viz., (C5Me5)2Yb(bipy-Me). Single crystals of the 4,4'-dimethylbipyridinecomplex undergo an irreversible, abrupt first order phase change at 228 Kthat shatters the single crystals. The magnetic susceptibility,represented in a delta vs. T plot, on this complex, in polycrystallineform undergoes reversible abrupt changes in the temperature regime 205 -212 K, which is suggested to be due to the way the individual molec ularunits pack in the unit cell. A qualitative model is proposed thataccounts for the sub-normal magnetic moments in theseytterbocene-bipyridine complexes.

  16. An improved thermodynamic model for the complexation of trivalent actinides and lanthanide with oxalic acid valid to high ionic strength.

    SciTech Connect

    Xiong, Yongliang; Thakur, Punam; Borkowski, Marian

    2015-07-30

    The dissociation constants of oxalic acid (Ox), and the stability constants of Am3+, Cm3+ and Eu3+ with Ox2– have been determined at 25 °C, over a range of concentration varying from 0.1 to 6.60 m NaClO4 using potentiometric titration and extraction techniques, respectively. The experimental data support the formation of complexes, M(Ox)n3 – 2n, where (M = Am3+, Cm3+ and Eu3+ and n = 1 and 2). The dissociation constant and the stability constant values measured as a function of NaClO4 concentration were used to estimate the Pitzer parameters for the respective interactions of Am3+, Cm3+ and Eu3+ with Ox. Furthermore, the stability constants data of Am3+ –Ox measured in NaClO4 and in NaCl solutions from the literature were simultaneously fitted in order to refine the existing actinide–oxalate complexation model that can be used universally in the safety assessment of radioactive waste disposal. The thermodynamic stability constant: log β0101 = 6.30 ± 0.06 and log β0102 = 10.84 ± 0.06 for Am3+ was obtained by simultaneously fitting data in NaCl and NaClO4 media. Additionally, log β0101 = 6.72 ± 0.08 and log β0102 = 11.05 ± 0.09 for the Cm3+ and log β0101 = 6.67 ± 0.08 and log β0102 = 11.15 ± 0.09 for the Eu3+ were calculated by extrapolation of data to zero ionic strength in NaClO4 medium only. For all stability constants, the Pitzer model gives an excellent representation of the data using interaction parameters β(0), β(1), and CΦ determined in this work. The thermodynamic model developed in this work will be useful in accurately modeling the potential solubility of trivalent

  17. Phosphorescent light-emitting iridium complexes serve as a hypoxia-sensing probe for tumor imaging in living animals

    NASA Astrophysics Data System (ADS)

    Takeuchi, Toshiyuki; Zhang, Shaojuan; Negishi, Kazuya; Yoshihara, Toshitada; Hosaka, Masahiro; Tobita, Seiji

    2010-02-01

    Iridium complex, a promising organic light-emitting diode material for next generation television and computer displays, emits phosphorescence. Phosphorescence is quenched by oxygen. We used this oxygen-quenching feature for imaging tumor hypoxia. Red light-emitting iridium complex Ir(btp)2(acac) (BTP) presented hypoxia-dependent light emission in culture cell lines, whose intensity was in parallel with hypoxia-inducible factor (HIF)-1 expression. BTP was further applied to imaging five nude mouse-transplanted tumors. All tumors presented a bright BTP-emitting image as early as 5 min after the injection. The BTP-dependent tumor image peaked at 1 to 2 h after the injection, and was then removed from tumors within 24 h. The minimal BTP image recognition size was at least 2 mm in diameter. By morphological examination and phosphorescence lifetime measurement, BTP is presumed to localize to the tumor cells, not to stay in the tumor microvessels by binding to albumin. The primary problem on suse of luminescent probe for tumor imaging is its weak penetrance to deep tissues from the skin surface. Since BTP is easily modifiable, we made BTP analogues with a longer excitation/emission wavelength to improve the tissue penetrance. One of them, BTPHSA, displayed 560/720 wavelength, and depicted its clear imaging from tumors transplanted over 6-7 mm deep from the skin surface. We suggest that BTP analogues have a vast potential for imaging hypoxic lesions such as tumor tissues.

  18. Biological and Clinical Aspects of Lanthanide Coordination Compounds

    PubMed Central

    Misra, Sudhindra N.; M., Indira Devi; Shukla, Ram S.

    2004-01-01

    The coordinating chemistry of lanthanides, relevant to the biological, biochemical and medical aspects, makes a significant contribution to understanding the basis of application of lanthanides, particularly in biological and medical systems. The importance of the applications of lanthanides, as an excellent diagnostic and prognostic probe in clinical diagnostics, and an anticancer material, is remarkably increasing. Lanthanide complexes based X-ray contrast imaging and lanthanide chelates based contrast enhancing agents for magnetic resonance imaging (MRI) are being excessively used in radiological analysis in our body systems. The most important property of the chelating agents, in lanthanide chelate complex, is its ability to alter the behaviour of lanthanide ion with which it binds in biological systems, and the chelation markedly modifies the biodistribution and excretion profile of the lanthanide ions. The chelating agents, especially aminopoly carboxylic acids, being hydrophilic, increase the proportion of their complex excreted from complexed lanthanide ion form biological systems. Lanthanide polyamino carboxylate-chelate complexes are used as contrast enhancing agents for Magnetic Resonance Imaging. Conjugation of antibodies and other tissue specific molecules to lanthanide chelates has led to a new type of specific MRI contrast agents and their conjugated MRI contrast agents with improved relaxivity, functioning in the body similar to drugs. Many specific features of contrast agent assisted MRI make it particularly effective for musculoskeletal and cerebrospinal imaging. Lanthanide-chelate contrast agents are effectively used in clinical diagnostic investigations involving cerebrospinal diseases and in evaluation of central nervous system. Chelated lanthanide complexes shift reagent aided 23Na NMR spectroscopic analysis is used in cellular, tissue and whole organ systems. PMID:18365075

  19. Complexation behavior of trivalent actinides and lanthanides with 1,10-phenanthroline-2,9-dicarboxylic acid based ligands: insight from density functional theory.

    PubMed

    Manna, Debashree; Ghanty, Tapan K

    2012-08-21

    We have investigated the complexation behavior of preorganized 1,10-phenanthroline-2,9-dicarboxylic acid (PDA) based ligands with trivalent lanthanides and actinides using density functional theory with various GGA type exchange-correlation functionals and different basis sets. New ligands have been designed from PDA through functionalization with soft donor atoms such as sulfur, resulting in mono-thio-dicarboxylic acids (TCA/TCA1) and di-thio-dicarboxylic acid (THIO). It has been found that selectivity in terms of complexation energy of actinides over lanthanides is the maximum with TCA1 where the metal-ligand binding is through the O atoms. This unusual feature where a softer actinide metal ion is bonded strongly with hard donor oxygen atoms has been explained using the popular chemical concepts, viz., Pearson's Hard-Soft-Acid-Base (HSAB) principle and the frontier orbital theory of chemical reactivity as proposed by Fukui. Detailed analysis within the framework of the HSAB principle indicates that the presence of softer nitrogen atoms in the phenanthroline moiety (which also act as donors to the metal ion) has a profound influence in changing the soft nature of the actinide ion, which in turn binds with the hard oxygen atoms in a stronger way as compared to the valence isoelectronic lanthanide ion. Also, the trends in the variation of calculated values of the metal-ligand bond distances and the corresponding complex formation energies have been rationalized using the Fukui reactivity indices corresponding to the metal ions and the donor sites. All the calculations have also been done in the presence of solvent. The "intra-ligand synergistic effect" demonstrated here for PDA or TCA1 with soft and hard donor centers might be very important in designing new ligands for selective extraction of various metal ions in a competitive environment. However, for TCA and THIO ligands with only soft donor centers, "intra-ligand synergism" may not be very efficient although

  20. Highly Efficient Visible-to-NIR Luminescence of Lanthanide(III) Complexes with Zwitterionic Ligands Bearing Charge-Transfer Character: Beyond Triplet Sensitization.

    PubMed

    Pan, Mei; Du, Bin-Bin; Zhu, Yi-Xuan; Yue, Mei-Qin; Wei, Zhang-Wen; Su, Cheng-Yong

    2016-02-12

    Two zwitterionic-type ligands featuring π-π* and intraligand charge-transfer (ILCT) excited states, namely 1,1'-(2,3,5,6-tetramethyl-1,4-phenylene)bis(methylene)dipyridinium-4-olate (TMPBPO) and 1-dodecylpyridin-4(1 H)-one (DOPO), have been prepared and applied to the assembly of lanthanide coordination complexes in an effort to understand the ligand-direction effect on the structure of the Ln complexes and the ligand sensitization effect on the luminescence of the Ln complexes. Due to the wide-band triplet states plus additional ILCT excitation states extending into lower energy levels, broadly and strongly sensitized photoluminescence of f→f transitions from various Ln(3+) ions were observed to cover the visible to near-infrared (NIR) regions. Among which, the Pr, Sm, Dy, and Tm complexes simultaneously display both strong visible and NIR emissions. Based on the isostructural feature of the Ln complexes, color tuning and single-component white light was achieved by preparation of solid solutions of the ternary systems Gd-Eu-Tb (for TMPBPO) and La-Eu-Tb and La-Dy-Sm (for DOPO). Moreover, the visible and NIR luminescence lifetimes of the Ln complexes with the TMPBPO ligand were investigated from 77 to 298 K, revealing a strong temperature dependence of the Tm(3+) ((3) H4 ) and Yb(3+) ((2) F5/2 ) decay dynamics, which has not been explored before for their coordination complexes.

  1. Five novel lanthanide complexes with 2-chloroquinoline-4-carboxylic acid and 1,10-phenanthroline: Crystal structures, molecular spectra, thermal properties and bacteriostatic activities

    NASA Astrophysics Data System (ADS)

    Wang, Ye; Jin, Cheng-Wei; He, Shu-Mei; Ren, Ning; Zhang, Jian-Jun

    2016-12-01

    Five novel lanthanide complexes [Ln2(2-ClQL)6(phen)2(H2O)2]·2H2O (Ln = Pr(1), Sm(2), Eu(3), Ho(4), Er(5)); 2-ClQL: 2-chloroquinoline-4-carboxylate; phen: 1,10-phenanthroline; were synthesized by conventional solution method at room temperature and characterized via elemental analysis, powder x-ray diffraction, Infrared spectroscopy and Raman spectrometry. The results indicate that complexes 1-5 are isostructural, and each Ln3+ ion is eight-coordinated adopting a distorted square antiprismatic molecular geometry. Binuclear complex 1 are stitched together via hydrogen bonding interactions to form 1D chains, and further to form 2D sheets by the π-π interactions. Luminescence investigation reveals that complex 3 displays strong red emission. TG/DTG-FTIR, reveal the thermal decomposition processes and products of title complexes. The bacteriostatic activities of the complexes were evaluated against Candida albicans, Escherichia coli, and Staphylococcus aureus.

  2. Luminescent lanthanide chelates and methods of use

    DOEpatents

    Selvin, Paul R.; Hearst, John

    1997-01-01

    The invention provides lanthanide chelates capable of intense luminescence. The celates comprise a lanthanide chelator covalently joined to a coumarin-like or quinolone-like sensitizer. Exemplary sensitzers include 2- or 4-quinolones, 2- or 4-coumarins, or derivatives thereof e.g. carbostyril 124 (7-amino-4-methyl-2-quinolone), coumarin 120 (7-amino-4-methyl-2-coumarin), coumarin 124 (7-amino-4-(trifluoromethyl)-2-coumarin), aminomethyltrimethylpsoralen, etc. The chelates form high affinity complexes with lanthanides, such as terbium or europium, through chelator groups, such as DTPA. The chelates may be coupled to a wide variety of compounds to create specific labels, probes, diagnostic and/or therapeutic reagents, etc. The chelates find particular use in resonance energy transfer between chelate-lanthanide complexes and another luminescent agent, often a fluorescent non-metal based resonance energy acceptor. The methods provide useful information about the structure, conformation, relative location and/or interactions of macromolecules.

  3. Me-3,2-HOPO Complexes of Near Infra-Red (NIR) Emitting Lanthanides: Efficient Sensitization of Yb(III) and Nd(III) in Aqueous Solution

    SciTech Connect

    Moore, Evan G.; Xu, Jide; Dodani, Sheel; Jocher, Christoph; D'Aleo, Anthony; Seitz, Michael; Raymond, Kenneth

    2009-11-10

    The synthesis, X-ray structure, solution stability, and photophysical properties of several trivalent lanthanide complexes of Yb(III) and Nd(III) using both tetradentate and octadentate ligand design strategies and incorporating the 1-methyl-3-hydroxy-pyridin-2-one (Me-3,2-HOPO) chelate group are reported. Both the Yb(III) and Nd(III) complexes have emission bands in the Near Infra-Red (NIR) region, and this luminescence is retained in aqueous solution ({Phi}{sub tot}{sup Yb} {approx} 0.09-0.22%). Furthermore, the complexes demonstrate very high stability (pYb {approx} 18.8-21.9) in aqueous solution, making them good candidates for further development as probes for NIR imaging. Analysis of the low temperature (77 K) photophysical measurements for a model Gd(III) complex were used to gain an insight into the electronic structure, and were found to agree well with corresponding TD-DFT calculations at the B3LYP/6-311G{sup ++}(d,p) level of theory for a simplified model monovalent sodium complex.

  4. Chirality sensing and size recognition of N-Boc-amino acids by cage-type dimeric lanthanide complexes: chirality detection of N-Boc-aspartate anions via luminescence colour change.

    PubMed

    Ito, Hiroshi; Shinoda, Satoshi

    2015-03-01

    Chiral luminescent lanthanide complexes, characterized by covalently-linked face-to-face octadentate cyclen (tetraaza-12-crown-4) ligands, specifically bound a chiral N-Boc-aspartate among various N-Boc amino acid anions to enhance Eu(III) luminescence intensity at 615 nm. The combination of Tb(III) and Eu(III) complexes enabled naked-eye discrimination of N-Boc-D- and L-aspartates via the luminescence colour change.

  5. Homo dinuclear lanthanide(III) complexes of a mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane: synthesis and characterization.

    PubMed

    Shakya, Pawan Raj; Singh, Angad Kumar; Rao, T R

    2011-09-01

    A mesogenic Schiff-base, N,N'-di-(4-decyloxysalicylidene)-1',6'-diaminohexane, H2ddsdh (abbreviated as H2L2) that exhibits smectic-B (SmB) mesophase, was synthesized and its structure studied by elemental analysis, mass spectrometry, NMR & IR spectral techniques. The Schiff-base, H2L2, upon condensation with hydrated lanthanide(III) nitrates, yields LnIII complexes of the general composition [Ln2(L2H2)3(NO3)4](NO3)2, where Ln=La, Pr, Nd, Sm, Eu, Gd, Tb, Dy and Ho. IR and NMR spectral data imply a bi-dentate bonding of the Schiff-base in its zwitterionic form (as L2H2) to the LnIII ions through two phenolate oxygens. The POM and DSC studies reveal that none of the LnIII complexes exhibits mesomorphism. Fluorescence studies show that the TbIII complex displays characteristic metal-centered fluorescence (solution state).

  6. A BTP1 prophage gene present in invasive non-typhoidal Salmonella determines composition and length of the O-antigen of the lipopolysaccharide.

    PubMed

    Kintz, Erica; Davies, Mark R; Hammarlöf, Disa L; Canals, Rocío; Hinton, Jay C D; van der Woude, Marjan W

    2015-04-01

    Salmonella Typhimurium isolate D23580 represents a recently identified ST313 lineage of invasive non-typhoidal Salmonellae (iNTS). One of the differences between this lineage and other non-iNTS S. Typhimurium isolates is the presence of prophage BTP1. This prophage encodes a gtrC gene, implicated in O-antigen modification. GtrC(BTP) (1) is essential for maintaining O-antigen length in isolate D23580, since a gtr(BTP) (1) mutant yields a short O-antigen. This phenotype can be complemented by gtrC(BTP) (1) or very closely related gtrC genes. The short O-antigen of the gtr(BTP) (1) mutant was also compensated by deletion of the BTP1 phage tailspike gene in the D23580 chromosome. This tailspike protein has a putative endorhamnosidase domain and thus may mediate O-antigen cleavage. Expression of the gtrC(BTP) (1) gene is, in contrast to expression of many other gtr operons, not subject to phase variation and transcriptional analysis suggests that gtrC is produced under a variety of conditions. Additionally, GtrC(BTP) (1) expression is necessary and sufficient to provide protection against BTP1 phage infection of an otherwise susceptible strain. These data are consistent with a model in which GtrC(BTP) (1) mediates modification of the BTP1 phage O-antigen receptor in lysogenic D23580, and thereby prevents superinfection by itself and other phage that uses the same O-antigen co-receptor. PMID:25586744

  7. The addition of a second lanthanide ion to increase the luminescence of europium(III) macrocyclic complexes

    SciTech Connect

    Bromm, A.J. Jr.; Vallarino, L.M.; Leif, R.C.; Quagliano, J.R.

    1998-12-29

    At present, the microscopic visualization of luminescent labels containing lanthanide(III) ions, primarily europium(III), as light-emitting centers is best performed with time-gated instrumentation, which by virtually eliminating the background fluorescence results in an improved signal to noise ratio. However, the use of the europium(III) macrocycle, Quantum Dye{trademark}, in conjunction with the strong luminescence enhancing effect (cofluorescence) of yttrium(III) or gadolinium(III), can eliminate the need for such specialized instrumentation. In the presence of Gd(III), the luminescence of the Eu(III)-macrocycles can be conveniently observed with conventional fluorescence instrumentation at previously unattainable low levels. The Eu(III) {sup 5}D{sub 0} {r_arrow} {sup 7}F{sub 2} emission of the Eu(III)-macrocycles was observed as an extremely sharp band with a maximum at 619 nm and a clearly resolved characteristic pattern. At very low Eu(III)-macrocycle concentrations, another sharp emission was detected at 614 nm, arising from traces of Eu(III) present in even the purest commercially available gadolinium products. Discrimination of the resolved emissions of the Eu(III)-macrocycle and Eu(III) contaminant should provide a means to further lower the limit of detection of the Eu(III)-macrocycle.

  8. Dependence of the mechanism and regularities of energy transfer in binuclear lanthanide complexes in solutions on the nature of the anion and solvent

    NASA Astrophysics Data System (ADS)

    Sveshnikova, E. B.; Dudar', S. S.; Lanin, V. E.; Ermolaev, V. L.

    2002-10-01

    The effect of anions contained in solutions on the energy transfer from Tb(III) and Dy(III) ions to different Ln(III) ions is investigated in aqueous and alcohol solutions. It is shown that the regularities revealed in the energy transfer are completely determined by the ratio between the dissociation rate of the binuclear complex and the rate of energy transfer in it. The rate constant k t of energy transfer in solutions in which labile binuclear complexes of Ln(III) ions are linked through the strong acid anions Cl-, NO{3/-}, and HSO{4/-} depends on the nature of ions in the pairs. It is demonstrated that the energy transfer in all the systems predominantly occurs through the induction-resonance mechanism. The rate constants k t in aqueous solutions of weak (acetic, salicylic, and carbonic) acids also depend on the nature of ions interacting in pairs but do not correlate with the Förster overlap integral of the spectra. In labile binuclear complexes, the interaction between these ions proceeds by the exchange-resonance mechanism at a distance of ≈0.4 nm. It is established that the constants k t in alcohol solutions of Ln(III) ions are virtually independent of the nature of the pairs of the ions interacting through the acetate bridge. A comparison of the dissociation rate constants for Ln-anion complexes in alcohol solutions and the expected intracomplex rates of energy transfer in the binuclear complexes offers a satisfactory explanation of the obtained results and makes it possible to determine the association constants for binuclear lanthanide complexes in these solutions.

  9. Sorption of trivalent lanthanides and actinides onto montmorillonite: Macroscopic, thermodynamic and structural evidence for ternary hydroxo and carbonato surface complexes on multiple sorption sites.

    PubMed

    Fernandes, M Marques; Scheinost, A C; Baeyens, B

    2016-08-01

    The credibility of long-term safety assessments of radioactive waste repositories may be greatly enhanced by a molecular level understanding of the sorption processes onto individual minerals present in the near- and far-fields. In this study we couple macroscopic sorption experiments to surface complexation modelling and spectroscopic investigations, including extended X-ray absorption fine structure (EXAFS) and time-resolved laser fluorescence spectroscopies (TRLFS), to elucidate the uptake mechanism of trivalent lanthanides and actinides (Ln/An(III)) by montmorillonite in the absence and presence of dissolved carbonate. Based on the experimental sorption isotherms for the carbonate-free system, the previously developed 2 site protolysis non electrostatic surface complexation and cation exchange (2SPNE SC/CE) model needed to be complemented with an additional surface complexation reaction onto weak sites. The fitting of sorption isotherms in the presence of carbonate required refinement of the previously published model by reducing the strong site capacity and by adding the formation of Ln/An(III)-carbonato complexes both on strong and weak sites. EXAFS spectra of selected Am samples and TRLFS spectra of selected Cm samples corroborate the model assumptions by showing the existence of different surface complexation sites and evidencing the formation of Ln/An(III) carbonate surface complexes. In the absence of carbonate and at low loadings, Ln/An(III) form strong inner-sphere complexes through binding to three Al(O,OH)6 octahedra, most likely by occupying vacant sites in the octahedral layers of montmorillonite, which are exposed on {010} and {110} edge faces. At higher loadings, Ln/An(III) binds to only one Al octahedron, forming a weaker, edge-sharing surface complex. In the presence of carbonate, we identified a ternary mono- or dicarbonato Ln/An(III) complex binding directly to one Al(O,OH)6 octahedron, revealing that type-A ternary complexes form with the one

  10. Ionization Energies of Lanthanides

    ERIC Educational Resources Information Center

    Lang, Peter F.; Smith, Barry C.

    2010-01-01

    This article describes how data are used to analyze the pattern of ionization energies of the lanthanide elements. Different observed pathways of ionization between different ground states are discussed, and the effects of pairing, exchange, and orbital interactions on ionization energies of the lanthanides are evaluated. When all the above…

  11. Breaking pseudo-symmetry in multiantennary complex N-glycans using lanthanide-binding tags and NMR pseudo-contact shifts.

    PubMed

    Canales, Angeles; Mallagaray, Alvaro; Pérez-Castells, Javier; Boos, Irene; Unverzagt, Carlo; André, Sadine; Gabius, Hans-Joachim; Cañada, Francisco Javier; Jiménez-Barbero, Jesús

    2013-12-16

    Controlling NMR shifts by lanthanides tagged to a "symmetrical" N-glycan reveals individual resonances for the residues of the otherwise identical A and B arms. This method provides a global perspective of conformational features and interactions in solution.

  12. Lanthanide(III) complexes of bis-semicarbazone and bis-imine-substituted phenanthroline ligands: solid-state structures, photophysical properties, and anion sensing.

    PubMed

    Nadella, Sandeep; Selvakumar, Paulraj M; Suresh, Eringathodi; Subramanian, Palani S; Albrecht, Markus; Giese, Michael; Fröhlich, Roland

    2012-12-21

    Phenanthroline-based hexadentate ligands L(1) and L(2) bearing two achiral semicarbazone or two chiral imine moieties as well as the respective mononuclear complexes incorporating various lanthanide ions, such as La(III), Eu(III), Tb(III), Lu(III), and Y(III) metal ions, were synthesized, and the crystal structures of [ML(1)Cl(3)] (M=La(III), Eu(III), Tb(III), Lu(III), or Y(III)) complexes were determined. Solvent or water molecules act as coligands for the rare-earth metals in addition to halide anions. The big Ln(III) ion exhibits a coordination number (CN) of 10, whereas the corresponding Eu(III), Tb(III), Lu(III), and Y(III) centers with smaller ionic radii show CN=9. Complexes of L(2), namely [ML(2)Cl(3)] (M=Eu(III), Tb(III), Lu(III), or Y(III)) ions could also be prepared. Only the complex of Eu(III) showed red luminescence, whereas all the others were nonluminescent. The emission properties of the Eu derivative can be applied as a photophysical signal for sensing various anions. The addition of phosphate anions leads to a unique change in the luminescence behavior. As a case study, the quenching behavior of adenosine-5'-triphosphate (ATP) was investigated at physiological pH value in an aqueous solvent. A specificity of the sensor for ATP relative to adenosine-5'-diphosphate (ADP) and adenosine-5'-monophosphate (AMP) was found. (31)P NMR spectroscopic studies revealed the formation of a [EuL(2)(ATP)] coordination species.

  13. Tuning the decay time of lanthanide-based near infrared luminescence from micro- to milliseconds through d-->f energy transfer in discrete heterobimetallic complexes.

    PubMed

    Torelli, Stéphane; Imbert, Daniel; Cantuel, Martine; Bernardinelli, Gérald; Delahaye, Sandra; Hauser, Andreas; Bünzli, Jean-Claude G; Piguet, Claude

    2005-05-20

    Inert and optically active pseudo-octahedral Cr(III)N6 and Ru(II)N6 chromophores have been incorporated by self-assembly into heterobimetallic triple-stranded helicates HHH-[CrLnL3]6+ and HHH-[RuLnL3]5+. The crystal structures of [CrLnL(3)](CF(3)SO(3))(6) (Ln=Nd, Eu, Yb, Lu) and [RuLnL3](CF3SO3)5 (Ln=Eu, Lu) demonstrate that the helical structure can accommodate metal ions of different sizes, without sizeable change in the intermetallic MLn distances. These systems are ideally suited for unravelling the molecular factors affecting the intermetallic nd-->4f communication. Visible irradiation of the Cr(III)N6 and Ru(II)N6 chromophores in HHH-[MLnL3]5/6+ (Ln=Nd, Yb, Er; M=Cr, Ru) eventually produces lanthanide-based near infrared (NIR) emission, after directional energy migration within the complexes. Depending on the kinetic regime associated with each specific d-f pair, the NIR luminescence decay times can be tuned from micro- to milliseconds. The origin of this effect, together with its rational control for programming optical functions in discrete heterobimetallic entities, are discussed. PMID:15779094

  14. Lanthanide complexes containing 5-methyl-1,2,4-triazolo[1,5-a] pyrimidin-7(4H)-one and their therapeutic potential to fight leishmaniasis and Chagas disease.

    PubMed

    Caballero, Ana B; Rodríguez-Diéguez, Antonio; Salas, Juan M; Sánchez-Moreno, Manuel; Marín, Clotilde; Ramírez-Macías, Inmaculada; Santamaría-Díaz, Noelia; Gutiérrez-Sánchez, Ramón

    2014-09-01

    In the last years, numerous and significant advances in lanthanide coordination chemistry have been achieved. The unique chemical nature of these metal ions which is conferred by their f-electrons has led to a wide range of coordination compounds with interesting structural, physical and also biological properties. Consequently, lanthanide complexes have found applications mainly in catalysis, gas adsorption, photochemistry and as diagnostic tools. However, research on their therapeutic potential and the understanding of their mechanism of action is still taking its first steps, and there is a distinct lack of research in the parasitology field. In the present work, we describe the synthesis and physical properties of seven new lanthanide complexes with the anionic form of the bioactive ligand 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one (HmtpO), namely [Ln(mtpO)3(H2O)6]·9H2O (Ln=La(III), Nd(III), Eu(III), Gd(III), Tb(III), Dy(III) and Er(III)). In addition, results on the in vitro antiproliferative activity against Leishmania spp. and Trypanosoma cruzi are described. The high activity of the new compounds against parasite proliferation and their low cytotoxicity against reference host cell lines show a great potential of this type of compounds to become a new generation of highly effective and non-toxic antiparasitic agents to fight the so considered neglected diseases leishmaniasis and Chagas disease.

  15. A lanthanide complex with dual biosensing properties: CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts) with europium DOTA-tetraglycinate.

    PubMed

    Coman, Daniel; Kiefer, Garry E; Rothman, Douglas L; Sherry, A Dean; Hyder, Fahmeed

    2011-12-01

    Responsive contrast agents (RCAs) composed of lanthanide(III) ion (Ln3R) complexes with a variety of1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetate (DOTA4S) derivatives have shown great potential as molecular imaging agents for MR. A variety of LnDOTA–tetraamide complexes have been demonstrated as RCAs for molecular imaging using chemical exchange saturation transfer (CEST). The CEST method detects proton exchange between bulk water and any exchangeable sites on the ligand itself or an inner sphere of bound water that is shifted by a paramagnetic Ln3R ion bound in the core of the macrocycle. It has also been shown that molecular imaging is possible when the RCA itself is observed (i.e. not its effect on bulk water) using a method called biosensor imaging of redundant deviation in shifts (BIRDS). The BIRDS method utilizes redundant information stored in the nonexchangeable proton resonances emanating from the paramagnetic RCA for ambient factors such as temperature and/or pH.Thus, CEST and BIRDS rely on exchangeable and nonexchangeable protons, respectively, for biosensing. We posited that it would be feasible to combine these two biosensing features into the same RCA (i.e. dual CEST and BIRDS properties). A complex between europium(III) ion (Eu3R) and DOTA–tetraglycinate [DOTA–(gly)S4] was used to demonstrate that its CEST characteristics are preserved, while its BIRDS properties are also detectable. The in vitro temperature sensitivity of EuDOTA–(gly)S4 was used to show that qualitative MR contrast with CEST can be calibrated using quantitative MR mapping with BIRDS, thereby enabling quantitative molecular imaging at high spatial resolution.

  16. Hydrolytic synthesis of novel lanthanide(III) complexes with pyridine-2,6-dicarboxylic acid: Characterization of the structure and the physical properties

    NASA Astrophysics Data System (ADS)

    Hojnik, Nuša; Kristl, Matjaž; Golobič, Amalija; Jagličić, Zvonko; Drofenik, Miha

    2015-01-01

    The coordination compounds of pyridine-2,6-dicarboxylic acid and two lanthanide(III) ions, Ho3+ and Dy3+, were hydrolytically synthesized in aqueous solutions at a slightly basic pH, and then characterized by thermogravimetric analysis, IR spectroscopy, magnetic measurements as well as X-ray powder and single-crystal diffraction analysis. The elemental analyses were performed to check the purity of the compounds. The formula for these compounds is identified as Na3[Ln(Pydc)3]ṡ14H2O (Ln = Ho, 1; Ln = Dy, 2) in agreement with the X-ray structural analysis and all the other experimental data. The absence of the 1709 cm-1 band corresponding to ν(C dbnd O) in the IR spectra of the compounds evidences the deprotonating of the carboxyl group. The very strong inductive effect of the metal ion that is readily coordinated by the carboxylate group of the zwitterionic ligand is responsible for the formation of the product. The single-crystal X-ray structural analysis revealed that compounds 1 and 2 are isostructural. Their structure can be described as interchanging layers of complex anions [Ln(Pydc)3]3 (Ln = Ho and Dy for 1 and 2, respectively) and layers of hydrated sodium cations. In complex anions the holmium and dysprosium atoms are coordinated by three crystallographically independent pyridinedicarboxylate ligands in tridentate-chelate mode, via one O atom of both carboxylate groups and the ring N atom. The coordination number is nine and the coordination polyhedron is a tricapped trigonal prism with O atoms at the corners.

  17. Semiempirical quantum chemistry model for the lanthanides: RM1 (Recife Model 1) parameters for dysprosium, holmium and erbium.

    PubMed

    Filho, Manoel A M; Dutra, José Diogo L; Rocha, Gerd B; Simas, Alfredo M; Freire, Ricardo O

    2014-01-01

    Complexes of dysprosium, holmium, and erbium find many applications as single-molecule magnets, as contrast agents for magnetic resonance imaging, as anti-cancer agents, in optical telecommunications, etc. Therefore, the development of tools that can be proven helpful to complex design is presently an active area of research. In this article, we advance a major improvement to the semiempirical description of lanthanide complexes: the Recife Model 1, RM1, model for the lanthanides, parameterized for the trications of Dy, Ho, and Er. By representing such lanthanide in the RM1 calculation as a three-electron atom with a set of 5 d, 6 s, and 6 p semiempirical orbitals, the accuracy of the previous sparkle models, mainly concentrated on lanthanide-oxygen and lanthanide-nitrogen distances, is extended to other types of bonds in the trication complexes' coordination polyhedra, such as lanthanide-carbon, lanthanide-chlorine, etc. This is even more important as, for example, lanthanide-carbon atom distances in the coordination polyhedra of the complexes comprise about 30% of all distances for all complexes of Dy, Ho, and Er considered. Our results indicate that the average unsigned mean error for the lanthanide-carbon distances dropped from an average of 0.30 Å, for the sparkle models, to 0.04 Å for the RM1 model for the lanthanides; for a total of 509 such distances for the set of all Dy, Ho, and Er complexes considered. A similar behavior took place for the other distances as well, such as lanthanide-chlorine, lanthanide-bromine, lanthanide, phosphorus and lanthanide-sulfur. Thus, the RM1 model for the lanthanides, being advanced in this article, broadens the range of application of semiempirical models to lanthanide complexes by including comprehensively many other types of bonds not adequately described by the previous models.

  18. Investigations of the effect of the non-manganese metal in heterometallic-oxido cluster models of the oxygen evolving complex of photosystem II: lanthanides as substitutes for calcium.

    PubMed

    Lin, Po-Heng; Takase, Michael K; Agapie, Theodor

    2015-01-01

    We report the syntheses and electrochemical properties of nine new clusters ([LLnMn(IV)3O4(OAc)3(DMF)n](+) (Ln = La(3+), Ce(3+), Nd(3+), Eu(3+), Gd(3+), Tb(3+), Dy(3+), Yb(3+), and Lu(3+), n = 2 or 3)) supported by a ligand (L(3-)) based on a 1,3,5-triarylbenzene motif appended with alkoxide and pyridine donors. All complexes were obtained by metal substitution of Ca(2+) with lanthanides upon treatment of previously reported LMn3CaO4(OAc)3(THF) with Ln(OTf)3. Structural characterization confirmed that the clusters contain the [LnMn3O4] cubane motif. The effect of the redox-inactive centers on the electronic properties of the Mn3O4 cores was investigated by cyclic voltammetry. A linear correlation between the redox potential of the cluster and the ionic radii or pKa of the lanthanide metal ion was observed. Chemical reduction of the LMn(IV)3GdO4(OAc)3(DMF)2 cluster with decamethylferrocene, resulted in the formation of LGdMn(IV)2Mn(III)O4(OAc)3(DMF)2, a rare example of mixed-valence [MMn3O4] cubane. The lanthanide-coordinated ligands can be substituted with other donors, including water, the biological substrate. PMID:25521310

  19. Synthesis and luminescence properties of two novel lanthanide (III) perchlorate complexes with bis(benzoylmethyl) sulfoxide and benzoic acid.

    PubMed

    Li, Wen-Xian; Chai, Wen-Juan; Sun, Xiao-Jun; Ren, Tie; Shi, Xiao-Yan

    2010-07-01

    Two novel ternary rare earth complexes of Tb(III) and Dy(III) perchlorates with bis(benzoylmethyl) sulfoxide (L) and benzoic acid (L') had been synthesized and characterized by elemental analysis, coordination titration analysis, molar conductivity, IR, TG-DSC, (1)HNMR and UV spectra. The results indicated that the composition of these complexes was REL(5)L'(ClO(4))(2) x nH(2)O (RE = Tb(III), Dy(III); L = C(6)H(5)COCH(2)SOCH(2)COC(6)H(5), L' = C(6)H(5)COO; n = 6,8). The fluorescence spectra illustrated that the ternary rare earth complexes presented stronger fluorescence intensities, longer lifetimes and higher fluorescence quantum efficiencies than the binary rare earth complexes REL(5) x (ClO(4))(3) x 2 H(2)O. After the introduction of the second ligand benzoic acid group, the relative fluorescence emission intensities and fluorescence lifetimes of the ternary complexes REL(5)L'(ClO(4))(2) x nH(2)O (RE = Tb(III), Dy(III)) enhanced more obviously than the binary complexes. This indicated that the presence of both organic ligands bis(benzoylmethyl) sulfoxide and the second ligand benzoic acid could sensitize fluorescence intensities of rare earth ions, and the introduction of benzoic acid group was resulted in the enhancement of the fluorescence properties of the ternary rare earth complexes. The phosphorescence spectra were also discussed.

  20. Comparative Study of f-Element Electronic Structure across a Series of Multimetallic Actinide, Lanthanide-Actinide and Lanthanum-Actinide Complexes Possessing Redox-Active Bridging Ligands

    SciTech Connect

    Schelter, Eric J.; Wu, Ruilian; Veauthier, Jacqueline M.; Bauer, Eric D.; Booth, Corwin H.; Thomson, Robert K.; Graves, Christopher R.; John, Kevin D.; Scott, Brian L.; Thompson, Joe D.; Morris, David E.; Kiplinger, Jaqueline L.

    2010-02-24

    A comparative examination of the electronic interactions across a series of trimetallic actinide and mixed lanthanide-actinide and lanthanum-actinide complexes is presented. Using reduced, radical terpyridyl ligands as conduits in a bridging framework to promote intramolecular metal-metal communication, studies containing structural, electrochemical, and X-ray absorption spectroscopy are presented for (C{sub 5}Me{sub 5}){sub 2}An[-N=C(Bn)(tpy-M{l_brace}C{sub 5}Me4R{r_brace}{sub 2})]{sub 2} (where An = Th{sup IV}, U{sup IV}; Bn = CH{sub 2}C{sub 6}H{sub 5}; M = La{sup III}, Sm{sup III}, Yb{sup III}, U{sup III}; R = H, Me, Et) to reveal effects dependent on the identities of the metal ions and R-groups. The electrochemical results show differences in redox energetics at the peripheral 'M' site between complexes and significant wave splitting of the metal- and ligand-based processes indicating substantial electronic interactions between multiple redox sites across the actinide-containing bridge. Most striking is the appearance of strong electronic coupling for the trimetallic Yb{sup III}-U{sup IV}-Yb{sup III}, Sm{sup III}-U{sup IV}-Sm{sup III}, and La{sup III}-U{sup IV}-La{sup III} complexes, [8]{sup -}, [9b]{sup -} and [10b]{sup -}, respectively, whose calculated comproportionation constant K{sub c} is slightly larger than that reported for the benchmark Creutz-Taube ion. X-ray absorption studies for monometallic metallocene complexes of U{sup III}, U{sup IV}, and U{sup V} reveal small but detectable energy differences in the 'white-line' feature of the uranium L{sub III}-edges consistent with these variations in nominal oxidation state. The sum of this data provides evidence of 5f/6d-orbital participation in bonding and electronic delocalization in these multimetallic f-element complexes. An improved, high-yielding synthesis of 4{prime}-cyano-2,2{prime}:6{prime},2{double_prime}-terpyridine is also reported.

  1. Semiempirical Quantum Chemistry Model for the Lanthanides: RM1 (Recife Model 1) Parameters for Dysprosium, Holmium and Erbium

    PubMed Central

    Filho, Manoel A. M.; Dutra, José Diogo L.; Rocha, Gerd B.; Simas, Alfredo M.; Freire, Ricardo O.

    2014-01-01

    Complexes of dysprosium, holmium, and erbium find many applications as single-molecule magnets, as contrast agents for magnetic resonance imaging, as anti-cancer agents, in optical telecommunications, etc. Therefore, the development of tools that can be proven helpful to complex design is presently an active area of research. In this article, we advance a major improvement to the semiempirical description of lanthanide complexes: the Recife Model 1, RM1, model for the lanthanides, parameterized for the trications of Dy, Ho, and Er. By representing such lanthanide in the RM1 calculation as a three-electron atom with a set of 5 d, 6 s, and 6 p semiempirical orbitals, the accuracy of the previous sparkle models, mainly concentrated on lanthanide-oxygen and lanthanide-nitrogen distances, is extended to other types of bonds in the trication complexes’ coordination polyhedra, such as lanthanide-carbon, lanthanide-chlorine, etc. This is even more important as, for example, lanthanide-carbon atom distances in the coordination polyhedra of the complexes comprise about 30% of all distances for all complexes of Dy, Ho, and Er considered. Our results indicate that the average unsigned mean error for the lanthanide-carbon distances dropped from an average of 0.30 Å, for the sparkle models, to 0.04 Å for the RM1 model for the lanthanides; for a total of 509 such distances for the set of all Dy, Ho, and Er complexes considered. A similar behavior took place for the other distances as well, such as lanthanide-chlorine, lanthanide-bromine, lanthanide, phosphorus and lanthanide-sulfur. Thus, the RM1 model for the lanthanides, being advanced in this article, broadens the range of application of semiempirical models to lanthanide complexes by including comprehensively many other types of bonds not adequately described by the previous models. PMID:24497945

  2. Five different types of η(8)-cyclooctatetraenyl-lanthanide half-sandwich complexes from one ligand set, including a "giant neodymium wheel".

    PubMed

    Sroor, Farid M; Hrib, Cristian G; Liebing, Phil; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T

    2016-09-14

    The lithium-cyclopropylethynylamidinates Li[c-C3H5-C[triple bond, length as m-dash]C-C(NR)2] (1a: R = (i)Pr, 1b: R = cyclohexyl (Cy)) have been used as precursors for the preparation of five new series of half-sandwich complexes. These complexes contain the large flat cyclooctatetraenyl ligand (C8H8(2-), commonly abbreviated as COT), and were isolated as solvated, unsolvated and inverse sandwich complexes. Treatment of the halide precursors [(COT)Pr(μ-Cl)(THF)2]2 with 1b and [(COT)Nd(μ-Cl)(THF)2]2 with 1a and 1b in THF in a 1 : 2 molar ratio, respectively, afforded (COT)Ln[μ-c-C3H5-C[triple bond, length as m-dash]C-C(NR)2]2Li(L) (2: Ln = Pr, R = Cy, L = Et2O; 3: Ln = Nd, R = (i)Pr, L = THF; 4: Ln = Nd, R = Cy, L = THF). Treatment of the dimeric cerium(iii) bis(cyclopropylethynylamidinate) complexes [{c-C3H5-C[triple bond, length as m-dash]C-C(NR)2}2Ce(μ-Cl)(THF)]2 (5: R = (i)Pr; 6: R = Cy) in situ with K2C8H8 in a 1 : 1 molar ratio in THF at room temperature afforded the inverse-sandwich complexes (μ-η(8):η(8)-COT)[Ce{c-C3H5-C[triple bond, length as m-dash]C-C(NR)2}2]2 (7: R = (i)Pr; 8: R = Cy). This reaction represents a new method for encapsulation of a planar (C8H8)(2-) ring in lanthanide complexes containing amidinate ligands in the outer decks. Novel unsolvated dinuclear lanthanide half-sandwich complexes were prepared by using the precursors 1a, 1b and COT(2-). Unlike the complexes 2-4, the reaction of [(COT)Pr(μ-Cl)(THF)2]2 with 1a afforded the unsolvated centrosymmetric complex [(COT)Pr(μ-c-C3H5-C[triple bond, length as m-dash]C-C(N(i)Pr)2)]2 (9). These dimeric structures could be also accessed by reaction of LnCl3 (Ln = Ce or Nd) with 1a or 1b and K2COT in a 1 : 1 : 1 molar ratio as a one-pot reaction to give novel [(COT)Ln(μ-c-C3H5-C[triple bond, length as m-dash]C-C(NR)2)]2 complexes (10: Ln = Ce, R = (i)Pr; 11: Ln = Ce, R = Cy; 12: Ln = Nd, R = (i)Pr). Similar treatment of HoCl3 with 1a or 1b and K2COT as three

  3. Five different types of η(8)-cyclooctatetraenyl-lanthanide half-sandwich complexes from one ligand set, including a "giant neodymium wheel".

    PubMed

    Sroor, Farid M; Hrib, Cristian G; Liebing, Phil; Hilfert, Liane; Busse, Sabine; Edelmann, Frank T

    2016-09-14

    The lithium-cyclopropylethynylamidinates Li[c-C3H5-C[triple bond, length as m-dash]C-C(NR)2] (1a: R = (i)Pr, 1b: R = cyclohexyl (Cy)) have been used as precursors for the preparation of five new series of half-sandwich complexes. These complexes contain the large flat cyclooctatetraenyl ligand (C8H8(2-), commonly abbreviated as COT), and were isolated as solvated, unsolvated and inverse sandwich complexes. Treatment of the halide precursors [(COT)Pr(μ-Cl)(THF)2]2 with 1b and [(COT)Nd(μ-Cl)(THF)2]2 with 1a and 1b in THF in a 1 : 2 molar ratio, respectively, afforded (COT)Ln[μ-c-C3H5-C[triple bond, length as m-dash]C-C(NR)2]2Li(L) (2: Ln = Pr, R = Cy, L = Et2O; 3: Ln = Nd, R = (i)Pr, L = THF; 4: Ln = Nd, R = Cy, L = THF). Treatment of the dimeric cerium(iii) bis(cyclopropylethynylamidinate) complexes [{c-C3H5-C[triple bond, length as m-dash]C-C(NR)2}2Ce(μ-Cl)(THF)]2 (5: R = (i)Pr; 6: R = Cy) in situ with K2C8H8 in a 1 : 1 molar ratio in THF at room temperature afforded the inverse-sandwich complexes (μ-η(8):η(8)-COT)[Ce{c-C3H5-C[triple bond, length as m-dash]C-C(NR)2}2]2 (7: R = (i)Pr; 8: R = Cy). This reaction represents a new method for encapsulation of a planar (C8H8)(2-) ring in lanthanide complexes containing amidinate ligands in the outer decks. Novel unsolvated dinuclear lanthanide half-sandwich complexes were prepared by using the precursors 1a, 1b and COT(2-). Unlike the complexes 2-4, the reaction of [(COT)Pr(μ-Cl)(THF)2]2 with 1a afforded the unsolvated centrosymmetric complex [(COT)Pr(μ-c-C3H5-C[triple bond, length as m-dash]C-C(N(i)Pr)2)]2 (9). These dimeric structures could be also accessed by reaction of LnCl3 (Ln = Ce or Nd) with 1a or 1b and K2COT in a 1 : 1 : 1 molar ratio as a one-pot reaction to give novel [(COT)Ln(μ-c-C3H5-C[triple bond, length as m-dash]C-C(NR)2)]2 complexes (10: Ln = Ce, R = (i)Pr; 11: Ln = Ce, R = Cy; 12: Ln = Nd, R = (i)Pr). Similar treatment of HoCl3 with 1a or 1b and K2COT as three

  4. Lanthanide complexes of the hexadentate N-donor podand tris[3-(2-pyridyl)pyrazolyl]hydroborate: Solid-state and solution properties

    SciTech Connect

    Jones, P.L.; Amoroso, A.J.; Jeffery, J.C.; Rees, L.H.

    1997-01-01

    The hexadentate N{sub 6}-donor podand tris[3-(2-pyridyl)pyrazolyl]hydroborate (Tp{sup Py}) contains 2-pyridyl fragments attached to the pyrazolyl C{sup 3}-positions such that each arm is a bidentate chelate. Three series of lanthanide(III) complexes were prepared: [M(Tp{sup Py})(MeOH){sub 2}F][PF{sub 6}] (series A), [M(Tp{sup Py})(NO{sub 3}){sub 2}] (series B), and [M(Tp{sup Py}){sub 2}]-[BPh{sub 4}] (series C). Crystallographic studies showed that series A and B have a 1:1 metal:Tp{sup Py} ratio, with the metal ion lying within the podand cavity and the remaining coordination sites occupied by solvent molecules and/or counterions to give 9-coordination (A, with one fluoride and two methanol ligands) or 10-coordination (B, with two bidentate nitrate ligands). The C complexes were prepared in the absence of any coordinating anions and have a 1:2 metal:Tp{sup Py} ratio with an unusual icosahedral geometry arising from coordination of the 12 nitrogen donors from two interleaved podands. Conductivity studies on the B complexes show that in water the nitrates dissociate to give [M(Tp{sup Py})(H{sub 2}O){sub q}](NO{sub 3}){sub 2}; the relaxivity of [Gd(Tp{sup Py}(NO{sub 3}){sub 2}] in water is 4.4 s{sup -1} mM{sup -1}, a value comparable to those of clinically useful MRI contrast enhancement agents. Comparison of emission lifetimes of [M(Tp{sup Py})(NO{sub 3}){sub 2}] M = Eu, Tb) in H{sub 2}O/d{sub 2}O and CH{sub 3}OH/Cd{sub 3}OD give values for q, the number of coordinated solvent molecules, of 3.6 (water) and 2.6 (methanol). The C complex [Tb(Tp{sup Py}){sub 2}][BPh{sub 4}] also has q = 2.6 in methanol, suggesting that partial ligand dissociation allows access of solvent molecules to the metal coordination sphere.

  5. Curvature of the Lanthanide Contraction: An Explanation

    SciTech Connect

    Raymond, Kenneth; Wellman, Daniel; Sgarlata, Carmelo; Hill, Aru

    2009-12-21

    A number of studies have shown that for isostructural series of the lanthanides (elements La through Lu), a plot of equivalent metal-ligand bond lengths versus atomic number differs significantly from linearity and can be better fit as a quadratic equation. However, for hydrogen type wave functions, it is the inverse of the average distance of the electron from the nucleus (an estimate of size) that varies linearly with effective nuclear charge. This generates an apparent quadratic dependence of radius with atomic number. Plotting the inverse of lanthanide ion radii (the observed distance minus the ligand size) as a function of effective nuclear charge gives very good linear fits for a variety of lanthanide complexes and materials. Parameters obtained from this fit are in excellent agreement with the calculated Slater shielding constant, k.

  6. Solvothermal syntheses and characterizations of three new holmium selenidostannates(iv): a rare example of adamantane-like [Sn4Se10](4-) selenidostannate(iv) with lanthanide complexes.

    PubMed

    Xiao, Hong-Ping; Zhou, Jian; Wang, Xiao-Li; Zou, Hua-Hong; Zhao, Rong-Qing; Xiao, Hong

    2014-08-28

    Three new holmium selenidostannates(iv), [Ho(dap)4]2[Sn2Se6]Cl2 (, dap = diaminopropane), {[Ho(dien)2]2(μ2-OH)2}[Sn2Se6] (, dien = diethylenetriamine), and [Ho2(tepa)2(μ2-OH)2Cl2]2[Sn4Se10]·4H2O (, tepa = tetraethylenepentamine), have been solvothermally synthesized and structurally characterized. consists of two mononuclear [Ho(dap)4](3+) complex cations, one [Sn2Se6](4-) anion built up from two [SnSe4] tetrahedra sharing a common edge, and two Cl(-) ions. consists of one binuclear holmium(iii) complex {[Ho(dien)2]2(μ2-OH)2}(4+) cation and one dimeric [Sn2Se6](4-) anion. is composed of rare binuclear holmium(iii) complex [Ho2(tepa)2(μ2-OH)2Cl2](2+) cations, adamantane-like [Sn4Se10](4-) and free water molecules. Although a few chalcogenidostannates(iv) with lanthanide(iii) complex cations acting as counterions have been reported, their anions are strongly dominated by the dimeric [Sn2Se6](4-) moieties. represents a rare example of an adamantane-like [Sn4Se10](4-) selenidostannate with lanthanide complexes as counterions. The optical properties of have been investigated by UV-vis spectroscopy.

  7. A [Cyclentetrakis(methylene)]tetrakis[2-hydroxybenzamide]Ligand That Complexes and Sensitizes Lanthanide(III) Ions

    SciTech Connect

    D'Aleo, Anthony; Xu, Jide; Do, King; Muller, Gilles; Raymond, Kenneth N.

    2009-04-30

    The synthesis of a cyclen derivative containing four isophthalamide groups (L{sup 1}) is described. The spectroscopic properties of the Ln(III) complexes of L{sup 1} (Ln = Gd, Tb, Yb, Eu) reveal changes of the UV/visible absorption, circular dichroism absorption, luminescence and circularly polarized luminescence properties. It is shown that at least two metal complex species are present in solution, whose relative amounts are pH dependent. When at pH > 8.0, an intense long lived emission is observed (for [L{sup 1}Tb] and [L{sup 1}Yb]) while at pH < 8.0, a weaker, shorter-lived species predominates. Unconventional Ln(III) emitters (Pr, Nd, Sm, Dy and Tm) were sensitized in basic solution, both in the visible and in the near infra-red, to measure the emission of these ions.

  8. Lanthanide coordination polymers: Synthesis, diverse structure and luminescence properties

    SciTech Connect

    Song, Xue-Qin Lei, Yao-Kun; Wang, Xiao-Run; Zhao, Meng-Meng; Peng, Yun-Qiao; Cheng, Guo-Quan

    2014-10-15

    The new semirigid exo-bidentate ligand incorporating furfurysalicylamide terminal groups, namely, 1,4-bis([(2′-furfurylaminoformyl)phenoxyl]methyl)-2,5-bismethylbenzene (L) was synthesized and used as building blocks for constructing lanthanide coordination polymers with luminescent properties. The series of lanthanide nitrate complexes have been characterized by elemental analysis, IR spectroscopy, and X-ray diffraction analysis. The semirigid ligand L, as a bridging ligand, reacts with lanthanide nitrates forming three distinct structure types: chiral noninterpenetrated two-dimensional (2D) honeycomblike (6,3) (hcb, Schläfli symbol 6{sup 3}, vertex symbol 6 6 6) topological network as type I, 1D zigzag chain as type II and 1D trapezoid ladder-like chain as type III. The structural diversities indicate that lanthanide contraction effect played significant roles in the structural self-assembled process. The luminescent properties of Eu{sup III}, Tb{sup III} and Dy{sup III} complexes are discussed in detail. Due to the good match between the lowest triplet state of the ligand and the resonant energy level of the lanthanide ion, the lanthanide ions in Eu{sup III}, Tb{sup III} and Dy{sup III} complexes can be efficiently sensitized by the ligand. - Graphical abstract: We present herein six lanthanide coordination polymers of a new semirigid exo-bidentate ligand which not only display diverse structures but also possess strong luminescence properties. - Highlights: • We present lanthanide coordination polymers of a new semirigid exo-bidentate ligand. • The lanthanide coordination polymers exhibit diverse structures. • The luminescent properties of Tb{sup III}, Eu{sup III} and Dy{sup III} complexes are discussed in detail.

  9. Trivalent scandium, yttrium and lanthanide complexes with thia-oxa and selena-oxa macrocycles and crown ether coordination.

    PubMed

    Champion, Martin J D; Farina, Paolo; Levason, William; Reid, Gillian

    2013-09-28

    Complexes of the oxa-thia macrocycles [18]aneO4S2, [15]aneO3S2 and the oxa-selena macrocycle [18]aneO4Se2 (L) of types [MCl2(L)]FeCl4 (M = Sc or Y) were prepared from [ScCl3(thf)3] or [YCl2(THF)5][YCl4(THF)2] and the ligand in anhydrous MeCN, using FeCl3 as a chloride abstractor. The [MI2(L)]I, [LaI3(L)] and [LuI2(L)]I have been prepared from the ligands and the appropriate anhydrous metal triiodide in MeCN. Complexes of type [LaI3(crown)] and [LuI2(crown)]I (crown = 18-crown-6, 15-crown-5) were made for comparison. Use of the metal iodide results in complexes with high solubility compared to the corresponding chlorides, although also with increased sensitivity to moisture. All complexes were characterised by microanalysis, IR, (1)H, (45)Sc and (77)Se NMR spectroscopy as appropriate. X-ray crystal structures are reported for [ScCl2([18]aneO4S2)][FeCl4], [ScI2([18]aneO4S2)]I, [YCl2(18-crown-6)]3[Y2Cl9], [YCl2([18]aneO4S2)][FeCl4], [LaI3(15-crown-5)], [LaI2(18-crown-6)(MeCN)]I, [LuI(18-crown-6)(MeCN)2]I2, [Lu(15-crown-5)(MeCN)2(OH2)]I3, [LaI3([18]aneO4S2)], [LaI([18]aneO4S2)(OH2)]I2, [LaI3([18]aneO4Se2)] and [LuI2([18]aneO4Se2)]I. In each complex all the neutral donor atoms of the macrocycles are coordinated to the metal centre, showing very rare examples of these oxophilic metal centres coordinated to thioether groups, and the first examples of coordinated selenoether donors. In some cases MeCN or adventitious water displaces halide ligands, but not the S/Se donors from La or Lu complexes. A complex of the oxa-tellura macrocycle [18]aneO4Te2, [ScCl2([18]aneO4Te2)][FeCl4] was isolated, but is unstable in MeCN solution, depositing elemental Te. YCl3 and 18-crown-6 produced [YCl2(18-crown-6)]3[Y2Cl9], the asymmetric unit of which contains two cations with a trans-YCl2 arrangement and a third with a cis-YCl2 group.

  10. Nuclear Magnetic Resonance Shift Reagents: Abnormal 13C Shifts Produced by Complexation of Lanthanide Chelates with Saturated Amines and n-Butyl Isocyanide

    PubMed Central

    Marzin, Claude; Leibfritz, Dieter; Hawkes, Geoffrey E.; Roberts, John D.

    1973-01-01

    Lanthanide-induced shfits of 13C nuclear magnetic resonances are reported for several amines and n-butyl isocyanide. Contact contributions to such shifts, especially of β carbons, are clearly important for the chelates of Eu+3 and Pr+3. The importance of contact terms is shown to change in a rather predictable manner with the structure of the amine. PMID:16592062

  11. Determination of solubility products of complex compounds of certain lanthanide and actinide diiodies with 18-crown-6 in tetrahydrofuran

    SciTech Connect

    Mikheev, N.B.; Kamenskaya, A.N.; Kulyukhin, S.A.

    1988-09-01

    The existence of divalent americium in a tetrahydrofuran (THF) solution was proved for the first time. The values of the solubility products (SP) of the complex compounds with the composition of MeI{sub 2}{centered dot}18-crown-6 (Me = Sm, Eu, Yb, Am, Cf, Es, Fm) in the THF solutions were determined by the cocrystallization method. The SP values obtained are within (5.9-7.9){centered dot}10{sup {minus}12} and are close to the SP value for SrI{sub 2}{centered dot}10{sup {minus}12}, which indicates a similarity in the properties of these elements.

  12. Slow Relaxation of Magnetization in an Isostructural Series of Zinc-Lanthanide Complexes: An Integrated EPR and AC Susceptibility Study.

    PubMed

    Amjad, Asma; Madalan, Augustin M; Andruh, Marius; Caneschi, Andrea; Sorace, Lorenzo

    2016-08-26

    We report the synthesis, structure, and spectroscopic and dynamic magnetic properties of a series of heterodinuclear complexes, [ZnLn(LH4 )2 ](NO3 )3 ⋅6 H2 O (Ln=Nd, Tb, Dy, Ho, Er, and Yb), with the singly deprotonated form of a new compartmentalized Schiff-base ligand, LH5 . The Ln(III) ions in these systems show a distorted square-antiprism geometry with an LnO8 coordination sphere. EPR spectroscopy and DC magnetic studies have shown that the anisotropic nature of the complexes is far more complicated than predicted on the basis of a simple electrostatic model. Among the investigated systems, only the Dy(III) derivative showed single-ion magnet behavior, in zero and an applied magnetic field, both in pure polycrystalline samples and in a series of polycrystalline samples with different degrees of dilution at the single-crystal level in the isostructural Y(III) derivative. The rich dynamics observed as functions of frequency, field, and temperature reveals that multiple relaxation mechanisms are at play, resulting in a barrier of 189 cm(-1) , which is among the highest reported for a dinuclear Zn-Dy system. Analysis of the dynamic behavior as a function of dilution degree further evidenced the persistence of non-negligible intermolecular interactions, even at the lowest concentration of 1 %. PMID:27465998

  13. Dissociation kinetics of macrocyclic trivalent lanthanide complexes of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (DO2A).

    PubMed

    Lin, Chih-Cheng; Chen, Chia-Ling; Liu, Kuan-Yu; Chang, C Allen

    2011-06-21

    The [H(+)]-catalyzed dissociation rate constants of several trivalent lanthanide (Ln) complexes of 1,4,7,10-tetraazacyclododecane-1,7-diacetic acid (LnDO2A(+), Ln = La, Pr, Eu, Er and Lu) have been determined in two pH ranges: 3.73-5.11 and 1.75-2.65 at four different temperatures (19-41.0 °C) in aqueous media at a constant ionic strength of 0.1 mol dm(-3) (LiClO(4)). For the study in the higher pH range, i.e. pH 3.73-5.11, copper(II) ion was used as the scavenger for the free ligand DO2A in acetate/acetic acid buffer medium. The rates of Ln(III) complex dissociation have been found to be independent of [Cu(2+)] and all the Ln(III) complexes studied show [H(+)]-dependence at low acid concentrations but become [H(+)]-independent at high acid concentrations. Influence of the acetate ion content in the buffer on the dissociation rate has also been investigated and all the complexes exhibit a first-order dependence on [Acetate]. The dissociation reactions follow the rate law: k(obs) = k(Ac)[Acetate] + K'k(lim)[H(+)]/(1 + K'[H(+)]) where k(AC) is the dissociation rate constant for the [Acetate]-dependent pathway, k(lim) is the limiting rate constant, and K' is the equilibrium constant for the reaction LnDO2A(+) + H(+) ⇔ LnDO2AH(2+). In the lower pH range, i.e. pH 1.75-2.65, the dye indicator, cresol red, was used to monitor the dissociation rate, and all the Ln(III) complexes also show [H(+)]-dependence dissociation pathways but without the rate saturation observed at higher pH range. The dissociation reactions follow the simple rate law: k(obs) = k(H)[H(+)], where k(H) is the dissociation rate constant for the pathway involving monoprotonated species. The absence of an [H(+)]-independent pathway in both pH ranges indicates that LnDO2A(+) complexes are kinetically rather inert. The obtained k(AC) values follow the order: LaDO2A(+) > PrDO2A(+) > EuDO2A(+) > ErDO2A(+) > LuDO2A(+), whereas the k(lim) and k(H) values follow the order: LaDO2A(+) > PrDO2A(+) > ErDO2A

  14. Structural variations across the lanthanide series of macrocyclic DOTA complexes: insights into the design of contrast agents for magnetic resonance imaging.

    PubMed

    Benetollo, F; Bombieri, G; Calabi, L; Aime, S; Botta, M

    2003-01-13

    associated with the decrease of the CN from 9 to 8. In [Sc(DOTA)](-), the even smaller ionic radius of Sc(III) shifts the geometry of the coordination cage to the more compact SA' typology with a twist angle of 41 degrees, a value very similar to that found in the SA structures of lanthanide(III) ions with CN 9. Finally, an investigation was made into the hydration spheres of the complexes with SA and TSA geometries to account for the experimental evidence of a markedly different rate of water exchange for the two isomeric structures. This is of fundamental importance to the understanding of the corresponding Gd(III) complexes as MRI contrast agents.

  15. Complex Magnetism of Lanthanide Intermetallics and the Role of their Valence Electrons: Ab Initio Theory and Experiment.

    PubMed

    Petit, L; Paudyal, D; Mudryk, Y; Gschneidner, K A; Pecharsky, V K; Lüders, M; Szotek, Z; Banerjee, R; Staunton, J B

    2015-11-13

    We explain a profound complexity of magnetic interactions of some technologically relevant gadolinium intermetallics using an ab initio electronic structure theory which includes disordered local moments and strong f-electron correlations. The theory correctly finds GdZn and GdCd to be simple ferromagnets and predicts a remarkably large increase of Curie temperature with a pressure of +1.5 K kbar(-1) for GdCd confirmed by our experimental measurements of +1.6  K kbar(-1). Moreover, we find the origin of a ferromagnetic-antiferromagnetic competition in GdMg manifested by noncollinear, canted magnetic order at low temperatures. Replacing 35% of the Mg atoms with Zn removes this transition, in excellent agreement with long-standing experimental data.

  16. Lanthanide(III)/actinide(III) differentiation in coordination of azine molecules to tris(cyclopentadienyl) complexes of cerium and uranium.

    PubMed

    Mehdoui, Thouraya; Berthet, Jean-Claude; Thuéry, Pierre; Ephritikhine, Michel

    2004-02-21

    Reaction of azine molecules L with the trivalent metallocenes [M(C5H4R)3](M = Ce, U; R = But, SiMe3) in toluene gave the Lewis base adducts [M(C5H4R)3(L)](L = pyridine, 3-picoline, 3,5-lutidine, 3-chloropyridine, pyridazine, pyrimidine, pyrazine, 3,5-dimethylpyrazine and s-triazine), except in the cases of M = U and L = 3-chloropyridine, pyridazine, pyrazine and s-triazine where oxidation of U(III) was found to occur. In the pairs of analogous compounds of Ce(III) and U(III), i.e.[M(C5H4But)3(L)](L = pyridine, picoline) and [M(C5H4SiMe3)3(L)](L = pyridine, lutidine, pyrimidine and dimethylpyrazine), the M-N and average M-C distances are longer for M = Ce than for M = U; however, within a series of azine adducts of the same metallocene, no significant variation is noted in the M-N and average M-C distances. The equilibria between [M(C5H4R)3], L and [M(C5H4R)3(L)] were studied by 1H NMR spectroscopy. The stability constants of the uranium complexes, KUL, are greater than those of the cerium counterparts, KCeL. The values of KML are much greater for R = SiMe3 than for R = But and a linear correlation is found between the logarithms of KML and the hydrogen-bond basicity pKHB scale of the azines. Thermodynamic parameters indicate that the enthalpy-entropy compensation effect holds for these complexation reactions. Competition reactions of [Ce(C5H4R)3] and [U(C5H4R)3] with L show that the selectivity of L in favour of U(III) increases with the [small pi] donor character of the metallocene and is proportional to the pi accepting ability of the azine molecule, measured by its reduction potential.

  17. Auto-ionization in lutetium iodide complexes: effect of the Iioic radius on lanthanide-iodide binding.

    PubMed

    Giesbrecht, Garth R; Gordon, John C; Clark, David L; Scott, Brian L

    2004-02-01

    Reaction of lutetium metal with 1.5 equiv of elemental iodine in 2-propanol leads to the isolation of LuI(3)(HO(i)Pr)(4) (1). An X-ray crystal structure reveals an ionic structure with well-separated [LuI(2)(HO(i)Pr)(4)] cations and [I] anions. Dissolution of 1 in pyridine generates the unusual alkoxide species [LuI(O(i)Pr)(py)(5)][I] (2) with the elimination of HI. An X-ray crystal structure of 2 confirmed the ionic nature of the compound, with the cationic portion of the complex exhibiting a seven-coordinated lutetium center with trans-disposed iodo and alkoxide ligands and five pyridine molecules equally displaced within the equatorial plane. Exposure of 2 to iodotrimethylsilane yields the expected triiodide species [LuI(2)(py)(5)][I] (3), which may also be prepared by refluxing commercially available LuI(3) in THF, followed by crystallization from a THF/pyridine mixture. The solid-state structure of 3 is similar to that of 2, with the alkoxide ligand having been replaced by an iodide. The formation of ionic structures 1-3 as opposed to the higher-coordinated neutral species may be traced to the small lutetium center and the presence of relatively strong Lewis bases within the coordination sphere of the metal. PMID:14753829

  18. Preparation, crystal structure and luminescent properties of the (6,3) type network supramolecular lanthanide picrate complexes with 2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide

    SciTech Connect

    Wang Qin; Tang Kuanzhen; Liu Weisheng; Tang Yu; Tan Minyu

    2009-11-15

    Solid complexes of lanthanide picrates with a new podand-type ligand, 2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide (L) have been prepared and characterized by elemental analysis, conductivity measurements, IR and electronic spectroscopies. The crystal and molecular structures of the coordination polymer {l_brace}[Eu{sub 2}L{sub 3}(Pic){sub 6}].(CHCl{sub 3}){sub 3}.(H{sub 2}O){sub 0.5}{r_brace}{sub n} have been determined by single-crystal X-ray diffraction, and the structure displays a two-dimensional honeycomb-like framework in the ab plane, which can be regarded as a (6,3) topological network with europium atoms acting as 'three-connected' centers. Furthermore, the coordination layers are linked by the intermolecular hydrogen bonds to form a three-dimensional (3-D) netlike supermolecule. Under excitation, Eu complex exhibited characteristic emissions. The lowest triplet state energy level of the ligand indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. - Graphical abstract: The (6,3) type network supramolecular luminescent lanthanide picrate complexes {l_brace}Ln{sub 2}L{sub 3}(Pic){sub 6}{r_brace}{sub n} (L=2,2'-[(1,2-naphthalene)bis(oxy)]bis[N-(phenylmethyl)]acetamide) displaying a two-dimensional honeycomb-like framework have been designed and prepared.

  19. Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate for dual biosensing of pH with chemical exchange saturation transfer (CEST) and biosensor imaging of redundant deviation in shifts (BIRDS).

    PubMed

    Huang, Yuegao; Coman, Daniel; Ali, Meser M; Hyder, Fahmeed

    2015-01-01

    Relaxivity-based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd(3+)) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the nonexchangeable or the exchangeable protons on the lanthanide complexes themselves. The nonexchangeable protons (e.g. -CHx, where 3 ≥ x ≥ 1) are detected using a three-dimensional chemical shift imaging method called biosensor imaging of redundant deviation in shifts (BIRDS), whereas the exchangeable protons (e.g. -OH or -NHy , where 2 ≥ y ≥ 1) are measured with chemical exchange saturation transfer (CEST) contrast. Here we tested the feasibility of BIRDS and CEST for pH imaging of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP(8-)) chelated with thulium (Tm(3+) ) and ytterbium (Yb(3+)). BIRDS and CEST experiments show that both complexes are responsive to pH and temperature changes. Higher pH and temperature sensitivities are obtained with BIRDS for either complex when using the chemical shift difference between two proton resonances vs using the chemical shift of a single proton resonance, thereby eliminating the need to use water resonance as reference. While CEST contrast for both agents is linearly dependent on pH within a relatively large range (i.e. 6.3-7.9), much stronger CEST contrast is obtained with YbDOTA-4AmP(5-) than with TmDOTA-4AmP(5-). In addition, we demonstrate the prospect of using BIRDS to calibrate CEST as new platform for quantitative pH imaging.

  20. Giant exchange interaction in mixed lanthanides

    PubMed Central

    Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

    2016-01-01

    Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction. PMID:27087470

  1. Giant exchange interaction in mixed lanthanides

    NASA Astrophysics Data System (ADS)

    Vieru, Veacheslav; Iwahara, Naoya; Ungur, Liviu; Chibotaru, Liviu F.

    2016-04-01

    Combining strong magnetic anisotropy with strong exchange interaction is a long standing goal in the design of quantum magnets. The lanthanide complexes, while exhibiting a very strong ionic anisotropy, usually display a weak exchange coupling, amounting to only a few wavenumbers. Recently, an isostructural series of mixed (Ln = Gd, Tb, Dy, Ho, Er) have been reported, in which the exchange splitting is estimated to reach hundreds wavenumbers. The microscopic mechanism governing the unusual exchange interaction in these compounds is revealed here by combining detailed modeling with density-functional theory and ab initio calculations. We find it to be basically kinetic and highly complex, involving non-negligible contributions up to seventh power of total angular momentum of each lanthanide site. The performed analysis also elucidates the origin of magnetization blocking in these compounds. Contrary to general expectations the latter is not always favored by strong exchange interaction.

  2. Luminescent 1-hydroxy-2-pyridinone chelates of lanthanides

    DOEpatents

    Raymond, Kenneth N.; Xu, Jide; Moore, Evan G.; Werner, Eric J.

    2013-10-15

    The present invention provides luminescent complexes between a lanthanide ion and an organic ligand which contains 1,2-hydroxypyridinone units. The complexes of the invention are stable in aqueous solutions and are useful as molecular probes, for example in medical diagnostics and bioanalytical assay systems. The invention also provides methods of using the complexes of the invention.

  3. Lanthanide-halide based humidity indicators

    DOEpatents

    Beitz, James V.; Williams, Clayton W.

    2008-01-01

    The present invention discloses a lanthanide-halide based humidity indicator and method of producing such indicator. The color of the present invention indicates the humidity of an atmosphere to which it is exposed. For example, impregnating an adsorbent support such as silica gel with an aqueous solution of the europium-containing reagent solution described herein, and dehydrating the support to dryness forms a substance with a yellow color. When this substance is exposed to a humid atmosphere the water vapor from the air is adsorbed into the coating on the pore surface of the silica gel. As the water content of the coating increases, the visual color of the coated silica gel changes from yellow to white. The color change is due to the water combining with the lanthanide-halide complex on the pores of the gel.

  4. Tailoring lanthanide nanocrystals for nanomedicine

    NASA Astrophysics Data System (ADS)

    Zhang, Yan; Tan, Timothy T. Y.

    2013-02-01

    Lanthanide nanocrystals have demonstrated strong potentials in nanomedicine due to its up-conversion and strong magnetic properties, and low toxicity. This talk will focus on strategies in lanthanide nanostructure tailoring to achieve up-conversion color emission tuning, MRI T1 and T2 contrast tuning, and the use of up-conversion fluorescence in drug delivery and cancer cells ablation.

  5. Complexations of Ln(III) with SnS{sub 4}H and Sn{sub 2}S{sub 6}: Solvothermal syntheses and characterizations of lanthanide coordination polymers with thiostannate and polyamine mixed ligands

    SciTech Connect

    Tang, Chunying; Lu, Jialin; Han, Jingyu; Liu, Yun; Shen, Yali; Jia, Dingxian

    2015-10-15

    Polymeric lanthanide complexes with thiostannate and polyamine mixed ligands, [Ln(peha)(μ–SnS{sub 4}H)]{sub n} [Ln=La (1a), Nd (1b)] and [(Ln(tepa)(μ–OH)){sub 2}(μ–Sn{sub 2}S{sub 6})]{sub n}nH{sub 2}O [Ln=Nd (2a), Sm (2b), Gd (2c), Dy (2d)] (peha=pentaethylenehexamine, tepa=tetraethylenepentamine) were respectively prepared in peha and tepa coordinative solvents by the solvothermal methods. In 1a and 1b, the Ln{sup 3+} ions are coordinated by a hexadentate peha ligand forming [Ln(peha)]{sup 3+} units. The [SnS{sub 4}H]{sup 3−} anion chelates a [Ln(peha)]{sup 3+} unit via two S atoms and coordinates to another [Ln(peha)]{sup 3+} unit via the third S atom. As a result, the [Ln(peha)]{sup 3+} units are connected into coordination polymers [Ln(peha)(μ–SnS{sub 4}H)]{sub n} by an unprecedented tridentate μ–η{sup 1},η{sup 2}–SnS{sub 4}H bridging ligands. In 2a–2d, the Ln{sup 3+} ions are coordinated by a pentadentate tepa ligand, and two [Ln(tepa)]{sup 3+} units are joined by two μ–OH bridges to form a binuclear [(Ln(tepa)(μ–OH)){sub 2}]{sup 4+} unit. Behaving as a bidentate μ–η{sup 1}, η{sup 1}–Sn{sub 2}S{sub 6} bridging ligand, the Sn{sub 2}S{sub 6} unit connects [(Ln(tepa)(μ–OH)){sub 2}]{sup 4+} units into a neutral coordination polymer [(Ln(tepa)(μ–OH)){sub 2}(μ–Sn{sub 2}S{sub 6})]{sub n} via the trans S atoms. The Ln{sup 3+} ions are in distorted monocapped square antiprismatic and bicapped trigonal prismatic environments in [(Ln(peha)(μ–SnS{sub 4}H)]{sub n} and [(Ln(tepa)(μ–OH)){sub 2}(μ–Sn{sub 2}S{sub 6})]{sub n}, respectively. The denticities of ethylene polyamine play an important role on the formation and complexation of the thiostannate in the presence of lanthanide ions. Compounds 1a–2d show well-defined absorption edges with band gaps between 2.81 and 3.15 eV. - Graphical abstract: Lanthanide coordination polymers concerning thiostannate ligands were prepared by the solvothermal methods, and μ{sub 3}

  6. Yttrium and lanthanide complexes of β-dialdehydes: synthesis, characterization and luminescence of coordination compounds with the conjugate base of nitromalonaldehyde.

    PubMed

    Bortoluzzi, Marco; Bianchin, Elena; Roppa, Stefania; Bertolasi, Valerio; Enrichi, Francesco

    2014-07-14

    Coordination compounds having formulae [AsPh4][Ln(NMA)4] (1(Ln)), Ln(NMA)3(tppo)2 (2(Ln)), Ln(NMA)3(bipyO2) (3(Ln)), Ln(NMA)3(phen) (4(Ln)) and Ln(NMA)3(terpy) (5(Ln)) (Ln = Y and some lanthanides; NMA = conjugate base of nitromalonaldehyde; tppo = triphenylphosphine oxide; bipyO2 = 2,2'-bipyridine-N,N'-dioxide; phen = 1,10-phenanthroline; terpy = 2,2':6',2''-terpyridine) were synthesized and characterized and X-ray diffraction data were collected for [AsPh4][Y(NMA)4] (1(Y)). The neutral europium derivatives showed appreciable luminescence in the solid state upon excitation with UV light and photoluminescence measurements were carried out. These compounds were used as dopants for the preparation of luminescent poly(methyl methacrylate). Luminescent polyvinylpyrrolidone samples were obtained by reacting the pure polymer with water solutions containing NMA and trivalent europium ions.

  7. Protonation at the aromatic ring vs at the carbonyl group of lanthanide-diaryl ketone dianion species by aryl alcohols. Formation, structural characterization, and reactivity of lanthanide aryloxide, mixed aryloxide/alkoxide, and aryloxide/enolate complexes

    SciTech Connect

    Yoshimura, Takashi; Hou, Z.; Wakatsuki, Yasua

    1995-11-01

    Reaction of the ytterbium-benzophenone dianion complex (1), which was formed by reaction of Yb metal with benzophenone in THF/HMPA, with 2,6-di-tert-butyl-4-methylphenol, yielded the ytterbium(II) aryloxide complex Yb(OAr){sub 2}(HMPA){sub 2} (2, Ar= C{sub 6}H{sub 2} -{sup t}Bu{sub 2}-2,6-Me-4) as a major product (80%) and the ytterbium(III) enolate complex (3) as a minor one (ca. 5% yield). The mechanisms of these reactions are discussed. X-ray crystallographic studies reveal that 3, 4a, and 7b are isostructural, and so are 5a and 6. The central metal ions in these complexes are all five-coordinated in a trigonal bipyramid form (highly distorted in the case of 5a and 6) with two HMPA ligands at the apical and three anionic oxygen ligands at the equatorial positions. 25 refs., 7 figs., 7 tabs.

  8. Luminescent hybrid lanthanide sulfates and lanthanide sulfonate-carboxylates with 1,10-phenanthroline involving in-situ oxidation of 2-mercaptonbenzoic acid

    SciTech Connect

    Zhong, Jie-Cen; Wan, Fang; Sun, Yan-Qiong; Chen, Yi-Ping

    2015-01-15

    A series of lanthanide sulfates and lanthanide sulfonate-carboxylates, [Ln{sub 2}(phen){sub 2}(SO{sub 4}){sub 3}(H{sub 2}O){sub 2}]{sub n} (I:Ln=Nd(1a), Sm(1b), Eu(1c), phen=1,10-phenanthroline) and [Ln(phen)(2-SBA)(BZA)]{sub n} (II: Ln=Sm(2a), Eu(2b), Dy(2c), 2-SBA=2-sulfobenzoate, BZA=benzoate) have been hydrothermally synthesized from lanthanide oxide, 2-mercaptonbenzoic acid with phen as auxiliary ligand and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra, TG analyses and luminescence spectroscopy. Interestingly, SO{sub 4}{sup 2−} anions in I came from the in situ deep oxidation of thiol groups of 2-mercaptonbenzoic acid while 2-sulfobenzoate and benzoate ligands in II from the middle oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. Compounds I are organic–inorganic hybrid lanthanide sulfates, which have rare one-dimensional column-like structures. Complexes II are binuclear lanthanide sulfonate-carboxylates with 2-sulfobenzoate and benzoate as bridges and 1,10-phenanthroline as terminal. Photoluminescence studies reveal that complexes I and II exhibit strong lanthanide characteristic emission bands in the solid state at room temperature. - Graphical abstract: Lanthanide sulfates and lanthanide sulfonate-carboxylates have been hydrothermally synthesized. Interestingly, sulfate anions, 2-sulfobenzoate and benzoate ligands came from the in situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. - Highlights: • In situ oxidation and desulfuration reactions of 2-mercaptonbenzoic acid. • The organic–inorganic hybrid lanthanide sulfates with one-dimensional column-like structure. • The dinuclear lanthanide sulfonate-carboxylates. • The emission spectra exhibit the characteristic transition of {sup 5}D{sub 0}→{sup 7}F{sub J} (J=0–4) of the Eu(III)

  9. A Ratiometric Luminescent Thermometer Co-doped with Lanthanide and Transition Metals.

    PubMed

    Li, Zhiqiang; Hou, Zhaohui; Ha, Denghui; Li, Huanrong

    2015-12-01

    Herein, we report the fabrication of a sensitive ratiometric and colorimetric luminescent thermometer with a wide operating-temperature range, from cryogenic temperatures up to high temperatures, through the combination of lanthanide and transition metal complexes. Benefiting from the transition metal complex as a self-reference, the lanthanide content in the mixed-coordination complex, Eu0.05(Mebip-mim bromine)0.15Zn0.95(Mebip-mim bromine)1.9, was lowered to 5%.

  10. Early Transcriptional Responses of Bovine Chorioallantoic Membrane Explants to Wild Type, ΔvirB2 or ΔbtpB Brucella abortus Infection

    PubMed Central

    Mol, Juliana P. S.; Costa, Erica A.; Carvalho, Alex F.; Sun, Yao-Hui; Tsolis, Reneé M.; Paixão, Tatiane A.; Santos, Renato L.

    2014-01-01

    The pathogenesis of the Brucella-induced inflammatory response in the bovine placenta is not completely understood. In this study we evaluated the role of the B. abortus Type IV secretion system and the anti-inflammatory factor BtpB in early interactions with bovine placental tissues. Transcription profiles of chorioallantoic membrane (CAM) explants inoculated with wild type (strain 2308), ΔvirB2 or ΔbtpB Brucella abortus were compared by microarray analysis at 4 hours post infection. Transcripts with significant variation (>2 fold change; P<0.05) were functionally classified, and transcripts related to defense and inflammation were assessed by quantitative real time RT-PCR. Infection with wild type B. abortus resulted in slightly more genes with decreased than increased transcription levels. Conversely, infection of trophoblastic cells with the ΔvirB2 or the ΔbtpB mutant strains, that lack a functional T4SS or that has impaired inhibition of TLR signaling, respectively, induced more upregulated than downregulated genes. Wild type Brucella abortus impaired transcription of host genes related to immune response when compared to ΔvirB and ΔbtpB mutants. Our findings suggest that proinflammatory genes are negatively modulated in bovine trophoblastic cells at early stages of infection. The virB operon and btpB are directly or indirectly related to modulation of these host genes. These results shed light on the early interactions between B. abortus and placental tissue that ultimately culminate in inflammatory pathology and abortion. PMID:25259715

  11. Tri- and tetra-substituted cyclen based lanthanide(III) ion complexes as ribonuclease mimics: a study into the effect of log Ka, hydration and hydrophobicity on phosphodiester hydrolysis of the RNA-model 2-hydroxypropyl-4-nitrophenyl phosphate (HPNP).

    PubMed

    Fanning, Ann-Marie; Plush, Sally E; Gunnlaugsson, Thorfinnur

    2015-05-28

    A series of tetra-substituted 'pseudo' dipeptide ligands of cyclen (1,4,7,10,-tetraazacyclododecane) and a tri-substituted 3'-pyridine ligand of cyclen, and the corresponding lanthanide(III) complexes were synthesised and characterised as metallo-ribonuclease mimics. All complexes were shown to promote hydrolysis of the phosphodiester bond of 2-hydroxypropyl-4-nitrophenyl phosphate (HPNP, τ1/2 = 5.87 × 10(3) h), a well known RNA mimic. The La(III) and Eu(III) tri-substituted 3'-pyridine lanthanide(III) complexes being the most efficient in promoting such hydrolysis at pH 7.4 and at 37 °C; with τ1/2 = 1.67 h for La(III) and 1.74 h for Eu(III). The series was developed to provide the opportunity to investigate the consequences of altering the lanthanide(III) ion, coordination ability and hydrophobicity of a metallo-cavity on the rate of hydrolysis using the model phosphodiester, HPNP, at 37 °C. To further provide information on the role that the log Ka of the metal bound water plays in phosphodiester hydrolysis the protonation constants and the metal ion stability constants of both a tri and tetra-substituted 3'pyridine complex were determined. Our results highlighted several key features for the design of lanthanide(III) ribonucelase mimics; the presence of two metal bound water molecules are vital for pH dependent rate constants for Eu(III) complexes, optimal pH activity approximating physiological pH (∼7.4) may be achieved if the log Ka values for both MLOH and ML(OH)2 species occur in this region, small changes to hydrophobicity within the metallo cavity influence the rate of hydrolysis greatly and an amide adjacent to the metal ion capable of forming hydrogen bonds with the substrate is required for achieving fast hydrolysis.

  12. Density functional theory investigations of the homoleptic tris(dithiolene) complexes [M(dddt)(3)](-q) (q = 3, 2 ; M = Nd(3+) and U(3+/4+)) related to lanthanide(III)/actinide(III) differentiation.

    PubMed

    Meskaldji, Samir; Belkhiri, Lotfi; Arliguie, Thérèse; Fourmigué, Marc; Ephritikhine, Michel; Boucekkine, Abdou

    2010-04-01

    The structures of the homoleptic lanthanide and actinide tris(dithiolene) complexes [M(dddt)(3)](q-) (q = 3, M = Nd(3+) and q = 3 or 2, M = U(3+/4+)) have been investigated using relativistic Density Functional Theory (DFT) computations including spin-orbit corrections coupled with the COnductor-like Screening Model (COSMO) for a realistic solvation approach. The dithiolene ligands are known to be very efficient at stabilizing metal high oxidation states. The aim of the work is to explain the peculiar symmetric folding of the three Mdddt metallacycles in these complexes, some of them existing under a polymeric form, in relation with the Ln(III)/An(III) differentiation. In the [M(dddt)(3)(py)](q-) species, where an additional pyridine ligand is linked to the metal center, the Mdddt moieties appear to be almost planar. The study brings to light the occurrence of a M...C=C interaction explaining the Mdddt folding of the [U(dddt)(3)](q-) uranium species, the metal 5f electrons playing a driving role. No such interaction appears in the case of the Nd(III) complex, and the folding of the rather flexible dddt ligands in the polymeric structure of this species should be mainly due to steric effects. Moreover, the analysis of the normal modes of vibration shows that the U(III) complex [U(dddt)(3)](3-), which has not yet been isolated, is thermodynamically stable. It appears that the X-ray characterized U(IV) complex [U(dddt)(3)](2-) should be less stable than the calculated U(III) complex in a polar solvent.

  13. Understanding stability trends along the lanthanide series.

    PubMed

    Regueiro-Figueroa, Martín; Esteban-Gómez, David; de Blas, Andrés; Rodríguez-Blas, Teresa; Platas-Iglesias, Carlos

    2014-04-01

    The stability trends across the lanthanide series of complexes with the polyaminocarboxylate ligands TETA(4-) (H4TETA=2,2',2'',2'''-(1,4,8,11-tetraazacyclotetradecane-1,4,8,11-tetrayl)tetraacetic acid), BCAED(4-) (H4BCAED=2,2',2'',2'''-{[(1,4-diazepane-1,4-diyl)bis(ethane-2,1-diyl)]bis(azanetriyl)}tetraacetic acid), and BP18C6(2-) (H2BP18C6=6,6'-[(1,4,10,13-tetraoxa-7,16-diazacyclooctadecane-7,16-diyl)bis(methylene)]dipicolinic acid) were investigated using DFT calculations. Geometry optimizations performed at the TPSSh/6-31G(d,p) level, and using a 46+4f(n) ECP for lanthanides, provide bond lengths of the metal coordination environments in good agreement with the experimental values observed in the X-ray structures. The contractions of the Ln(3+) coordination spheres follow quadratic trends, as observed previously for different isostructural series of complexes. We show here that the parameters obtained from the quantitative analysis of these data can be used to rationalize the observed stability trends across the 4f period. The stability trends along the lanthanide series were also evaluated by calculating the free energy for the reaction [La(L)](n+/-)(sol)+Ln(3+)(sol)→[Ln(L)](n+/-)(sol)+La(3+)(sol). A parameterization of the Ln(3+) radii was performed by minimizing the differences between experimental and calculated standard hydration free energies. The calculated stability trends are in good agreement with the experimental stability constants, which increase markedly across the series for BCAED(4-) complexes, increase smoothly for the TETA(4-) analogues, and decrease in the case of BP18C6(2-) complexes. The resulting stability trend is the result of a subtle balance between the increased binding energies of the ligand across the lanthanide series, which contribute to an increasing complex stability, and the increase in the absolute values of hydration energies along the 4f period.

  14. Complexations of Ln(III) with SnS4H and Sn2S6: Solvothermal syntheses and characterizations of lanthanide coordination polymers with thiostannate and polyamine mixed ligands

    NASA Astrophysics Data System (ADS)

    Tang, Chunying; Lu, Jialin; Han, Jingyu; Liu, Yun; Shen, Yali; Jia, Dingxian

    2015-10-01

    Polymeric lanthanide complexes with thiostannate and polyamine mixed ligands, [Ln(peha)(μ-SnS4H)]n [Ln=La (1a), Nd (1b)] and [{Ln(tepa)(μ-OH)}2(μ-Sn2S6)]nnH2O [Ln=Nd (2a), Sm (2b), Gd (2c), Dy (2d)] (peha=pentaethylenehexamine, tepa=tetraethylenepentamine) were respectively prepared in peha and tepa coordinative solvents by the solvothermal methods. In 1a and 1b, the Ln3+ ions are coordinated by a hexadentate peha ligand forming [Ln(peha)]3+ units. The [SnS4H]3- anion chelates a [Ln(peha)]3+ unit via two S atoms and coordinates to another [Ln(peha)]3+ unit via the third S atom. As a result, the [Ln(peha)]3+ units are connected into coordination polymers [Ln(peha)(μ-SnS4H)]n by an unprecedented tridentate μ-η1,η2-SnS4H bridging ligands. In 2a-2d, the Ln3+ ions are coordinated by a pentadentate tepa ligand, and two [Ln(tepa)]3+ units are joined by two μ-OH bridges to form a binuclear [{Ln(tepa)(μ-OH)}2]4+ unit. Behaving as a bidentate μ-η1, η1-Sn2S6 bridging ligand, the Sn2S6 unit connects [{Ln(tepa)(μ-OH)}2]4+ units into a neutral coordination polymer [{Ln(tepa)(μ-OH)}2(μ-Sn2S6)]n via the trans S atoms. The Ln3+ ions are in distorted monocapped square antiprismatic and bicapped trigonal prismatic environments in [{Ln(peha)(μ-SnS4H)]n and [{Ln(tepa)(μ-OH)}2(μ-Sn2S6)]n, respectively. The denticities of ethylene polyamine play an important role on the formation and complexation of the thiostannate in the presence of lanthanide ions. Compounds 1a-2d show well-defined absorption edges with band gaps between 2.81 and 3.15 eV.

  15. Tetrathiafulvalene-amido-2-pyridine-N-oxide as efficient charge-transfer antenna ligand for the sensitization of Yb(III) luminescence in a series of lanthanide paramagnetic coordination complexes.

    PubMed

    Pointillart, Fabrice; Cauchy, Thomas; Maury, Olivier; Le Gal, Yann; Golhen, Stéphane; Cador, Olivier; Ouahab, Lahcène

    2010-10-18

    The tetrathiafulvalene-amido-2-pyridine-N-oxide (L) ligand has been employed to coordinate 4f elements. The architecture of the complexes mainly depends on the ionic radii of the lanthanides. Thus, the reaction of L in the same experimental protocol leads to three different molecular structure series. Binuclear [Ln(2)(hfac)(5)(O(2)CPhCl)(L)(3)]·2 H(2)O (hfac(-)=1,1,1,5,5,5-hexafluoroacetylacetonate anion, O(2)CPhCl(-)=3-chlorobenzoate anion) and mononuclear [Ln(hfac)(3)(L)(2)] complexes were obtained by using rare-earth ions with either large (Ln(III)=Pr, Gd) or small (Ln(III)=Y, Yb) ionic radius, respectively, whereas the use of Tb(III) that possesses an intermediate ionic radius led to the formation of a binuclear complex of formula [Tb(2)(hfac)(4)(O(2)CPhCl)(2)(L)(2)]. Antiferromagnetic interactions have been observed in the three dinuclear compounds by using an extended empirical method. Photophysical properties of the coordination complexes have been studied by solid-state absorption spectroscopy, whereas time-dependent density functional theory (TD-DFT) calculations have been carried out on the diamagnetic Y(III) derivative to build a molecular orbital diagram and to reproduce the absorption spectrum. For the [Yb(hfac)(3)(L)(2)] complex, the excitation at 19,600 cm(-1) of the HOMO→LUMO+1/LUMO+2 charge-transfer transition induces both line-shape emissions in the near-IR spectral range assigned to the (2)F(5/2)→(2)F(7/2) (9860 cm(-1)) ytterbium-centered transition and a residual charge-transfer emission around 13,150 cm(-1). An efficient antenna effect that proceeds through energy transfer from the singlet excited state of the tetrathiafulvalene-amido-2-pyridine-N-oxide chromophore is evidence of the Yb(III) sensitization.

  16. The Lanthanide Contraction beyond Coordination Chemistry.

    PubMed

    Ferru, Geoffroy; Reinhart, Benjamin; Bera, Mrinal K; Olvera de la Cruz, Monica; Qiao, Baofu; Ellis, Ross J

    2016-05-10

    The lanthanide contraction is conceptualized traditionally through coordination chemistry. Here we break this mold in a structural study of lanthanide ions dissolved in an amphiphilic liquid. The lanthanide contraction perturbs the weak interactions between molecular aggregates that drive mesoscale assembly and emergent behavior. The weak interactions correlate with lanthanide ion transport properties, suggesting new strategies for rare-earth separation that exploit forces outside of the coordination sphere.

  17. Fixation of carbon dioxide by macrocyclic lanthanide(III) complexes under neutral conditions producing self-assembled trimeric carbonato-bridged compounds with μ3-η2:η2:η2 bonding.

    PubMed

    Bag, Pradip; Dutta, Supriya; Biswas, Papu; Maji, Swarup Kumar; Flörke, Ulrich; Nag, Kamalaksha

    2012-03-28

    A series of mononuclear lanthanide(III) complexes [Ln(LH(2))(H(2)O)(3)Cl](ClO(4))(2) (Ln = La, Nd, Sm, Eu, Gd, Tb, Lu) of the tetraiminodiphenolate macrocyclic ligand (LH(2)) in 95 : 5 (v/v) methanol-water solution fix atmospheric carbon dioxide to produce the carbonato-bridged trinuclear complexes [{Ln(LH(2))(H(2)O)Cl}(3)(μ(3)-CO(3))](ClO(4))(4)·nH(2)O. Under similar conditions, the mononuclear Y(III) complex forms the dimeric compound [{Y(LH(2))(H(2)O)Cl}(μ(2)-CO(3)){Y(LH(2))(H(2)O)(2)}](ClO(4))(3)·4H(2)O. These complexes have been characterized by their IR and NMR ((1)H, (13)C) spectra. The X-ray crystal structures have been determined for the trinuclear carbonato-bridged compounds of Nd(III), Gd(III) and Tb(III) and the dinuclear compound of Y(III). In all cases, each of the metal centers are 8-coordinate involving two imine nitrogens and two phenolate oxygens of the macrocyclic ligand (LH(2)) whose two other imines are protonated and intramolecularly hydrogen-bonded with the phenolate oxygens. The oxygen atoms of the carbonate anion in the trinuclear complexes are bonded to the metal ions in tris-bidentate μ(3)-η(2):η(2):η(2) fashion, while they are in bis-bidentate μ(2)-η(2):η(2) mode in the Y(III) complex. The magnetic properties of the Gd(III) complex have been studied over the temperature range 2 to 300 K and the magnetic susceptibility data indicate a very weak antiferromagnetic exchange interaction (J = -0.042 cm(-1)) between the Gd(III) centers (S = 7/2) in the metal triangle through the carbonate bridge. The luminescence spectral behaviors of the complexes of Sm(III), Eu(III), and Tb(III) have been studied. The ligand LH(2) acts as a sensitizer for the metal ions in an acetonitrile-toluene glassy matrix (at 77 K) and luminescence intensities of the complexes decrease in the order Eu(3+) > Sm(3+) > Tb(3+).

  18. Multicolor (Vis-NIR) mesoporous silica nanospheres linked with lanthanide complexes using 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline for in vitro bioimaging.

    PubMed

    Liu, Ying; Sun, Lining; Liu, Jinliang; Peng, Yu-Xin; Ge, Xiaoqian; Shi, Liyi; Huang, Wei

    2015-01-01

    A novel mesoporous nanosphere functionalized with 3-(aminopropyl)triethoxysilane (APTES) and 2-(5-bromothiophen)imidazo[4,5-f][1,10]phenanthroline (5-Br-Tip) was synthesized (denoted as Tip-MSS). With the coordinating function of the 5-Br-Tip to lanthanide (Ln) ions, for the first time, LnL3(5-Br-Tip) complexes were linked to the mesoporous nanospheres. The derived materials, named Ln-Tip-MSS (Ln = Eu, Tb, Sm, Nd, Yb), were characterized by Fourier-transform infrared (FT-IR) spectroscopy, TEM, XRD (wide-angle and small-angle), N2 adsorption/desorption analysis, and fluorescence spectroscopy. Upon excitation in the ligand absorption, the Ln-Tip-MSS nanomaterials show characteristic visible (Eu, Tb, Sm) and NIR (Sm, Nd, Yb) luminescence (multicolor emission covered from 450 nm to 1400 nm spectral region). Of importance is that, with low cytotoxicity and good biocompatibility given by the methyl thiazolyl tetrazolium (MTT) assay, the Eu-Tip-MSS was successfully applied to cell imaging in vitro based on the Eu(3+) luminescence (under 405 nm excitation).

  19. Synthesis and characterization of lanthanide(III) (La, Gd, Yb, Y) disalicylidene-1,2-phenylenediamine (H{sub 2}dsp) Schiff-base complexes

    SciTech Connect

    Chen, Huiyong; Archer, R.D.

    1994-11-09

    Novel rare earth (III) disalicylidene-1,2-phenylenediamine(H{sub 2}dsp) complexes with the formula M[Ln(dsp){sub 2}] (M = Li, Na, K, Cs) were prepared. UV-visible absorption and NMR were used to study the disproportionation equilibrium for these complexes in DMSO. Structures for these complexes are suggested.

  20. Experimental and theoretical comparison of actinide and lanthanide bonding in M[N(EPR(2))(2)](3) complexes (M = U, Pu, La, Ce; E = S, Se, Te; R = Ph, iPr, H).

    PubMed

    Gaunt, Andrew J; Reilly, Sean D; Enriquez, Alejandro E; Scott, Brian L; Ibers, James A; Sekar, Perumal; Ingram, Kieran I M; Kaltsoyannis, Nikolas; Neu, Mary P

    2008-01-01

    Treatment of M[N(SiMe3)2]3 (M = U, Pu (An); La, Ce (Ln)) with NH(EPPh2)2 and NH(EPiPr2)2 (E = S, Se), afforded the neutral complexes M[N(EPR2)2]3 (R = Ph, iPr). Tellurium donor complexes were synthesized by treatment of MI3(sol)4 (M = U, Pu; sol = py and M = La, Ce; sol = thf) with Na(tmeda)[N(TePiPr2)2]. The complexes have been structurally and spectroscopically characterized with concomitant computational modeling through density functional theory (DFT) calculations. The An-E bond lengths are shorter than the Ln-E bond lengths for metal ions of similar ionic radii, consistent with an increase in covalent interactions in the actinide bonding relative to the lanthanide bonding. In addition, the magnitude of the differences in the bonding is slightly greater with increasing softness of the chalcogen donor atom. The DFT calculations for the model systems correlate well with experimentally determined metrical parameters. They indicate that the enhanced covalency in the M-E bond as group 16 is descended arises mostly from increased metal d-orbital participation. Conversely, an increase in f-orbital participation is responsible for the enhancement of covalency in An-E bonds compared to Ln-E bonds. The fundamental and practical importance of such studies of the role of the valence d and f orbitals in the bonding of the f elements is emphasized.

  1. Towards inert and preorganized d-block-containing receptors for trivalent lanthanides: the synthesis and characterization of triple-helical monometallic Os(II) and bimetallic Os(II)-Ln(III) complexes.

    PubMed

    Riis-Johannessen, Thomas; Dupont, Nathalie; Canard, Gabriel; Bernardinelli, Gérald; Hauser, Andreas; Piguet, Claude

    2008-07-28

    The mononuclear Os(II) complex [Os()(3)](PF(6))(2) ( = 5-methyl(1-methylbenzimidazol-2-yl)pyridine) is an obvious candidate for the design of an inert d-block-based tripodal receptor capable of binding and photosensitizing trivalent lanthanides (Ln(III)). It has thus been prepared and its two enantiomeric meridional (Delta-mer and Lambda-mer) and facial (rac-fac) isomers have been separated by ion-exchange chromatography. The optical isomers have been characterized by CD spectroscopy and assignments of absolute configuration confirmed by an X-ray crystallographic study of Lambda-mer-[Os()(3)](PF(6))(2).1.5MeCN (monoclinic, P2(1), Z = 4). Comparison of the latter structure with that of racemic fac-[Os()(3)](PF(6))(2) (monoclinic, C2/c, Z = 8) and [Os(bipy)(3)](PF(6))(2) (where bipy = 2,2'-bipyridine) shows minimal structural variations, but differences are observed in the photophysical and electrochemical properties of the respective compounds. Luminescence emissions from Os(II) complexes of are typically lower in energy, with shorter lifetimes and lower quantum yields than their bipy analogues, whilst metal-centred oxidation processes are more facile due to the enhanced pi-donor ability of . The key relationships between these parameters are discussed. Finally, though challenged by (i) the low reactivity of many osmium precursors and (ii) the irreversible formation of competing side products, the synthesis and purification of the heterobimetallic triple-stranded helicate HHH-[OsLu()(3)](CF(3)SO(3))(5) has been realised, in which is a segmental ligand containing the same bidentate unit as that found in further connected to a tridentate binding site adapted for complexing Ln(III). Its solid-state structure has been established by X-ray crystallography (triclinic, P1, Z = 2). PMID:18615212

  2. Magnetic field alignable domains in phospholipid vesicle membranes containing lanthanides.

    PubMed

    Beck, Paul; Liebi, Marianne; Kohlbrecher, Joachim; Ishikawa, Takashi; Rüegger, Heinz; Zepik, Helmut; Fischer, Peter; Walde, Peter; Windhab, Erich

    2010-01-14

    Magnetic fields were applied as a structuring force on phospholipid-based vesicular systems, using paramagnetic lanthanide ions as magnetic handles anchored to the vesicle membrane. Different vesicle formulations were investigated using small angle neutron scattering (SANS) in a magnetic field of up to 8 T, cryo-transmission electron microscopy (cryo-TEM), (31)P NMR spectroscopy, dynamic light scattering (DLS), and permeability measurements with a fluorescent water-soluble marker (calcein). The investigated vesicle formulations consisted usually of 80 mol % of the phospholipid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and 20 mol % of a chelator lipid (DMPE-DTPA; 1,2-dimyristoyl-sn-glycero-3-phosphoethanolamine-diethylenetriaminepentaacetate) with complexed lanthanide ions (Tm(3+), Dy(3+), or La(3+)), and the total lipid concentration was 15 mM. Vesicles containing the paramagnetic lanthanide Tm(3+) or Dy(3+) exhibited a temperature-dependent response to magnetic fields, which can be explained by considering the formation of lipid domains, which upon reaching a critical size become alignable in a magnetic field. The features of this "magnetic field alignable domain model" are as follows: with decreasing temperature (from 30 to 2.5 degrees C) solid domains, consisting mainly of the higher melting phospholipid (DMPE-DTPA.lanthanide), begin to form and grow in size. The domains assemble the large magnetic moments conferred by the lanthanides and orient in magnetic fields. The direction of alignment depends on the type of lanthanide used. The domains orient with their normal parallel to the magnetic field with thulium (Tm(3+)) and perpendicular with dysprosium (Dy(3+)). No magnetic field alignable domains were observed if DMPE-DTPA is replaced either by POPE-DTPA (1-palmitoyl-2-oleoyl-sn-glycero-3-phosphoethanolamine-diethylenetriamine-pentaacetate) or by DMPC (1,2-dimyristoyl-sn-glycero-3-phosphocholine).

  3. Lanthanides: New life metals?

    PubMed

    Chistoserdova, Ludmila

    2016-08-01

    Lanthanides (Ln(3+)) that are Rare Earth Elements, until recently thought to be biologically inert, have recently emerged as essential metals for activity and expression of a special type of methanol dehydrogenase, XoxF. As XoxF enzyme homologs are encoded in a wide variety of microbes, including microbes active in important environmental processes such as methane and methanol metabolism, Ln(3+) may represent some of the key biogeochemical drivers in cycling of carbon and other elements. However, significant gaps in understanding the role of Ln(3+) in biological systems remain as the functions of most of the proteins potentially dependent of Ln(3+) and their roles in specific metabolic networks/respective biogeochemical cycles remain unknown. Moreover, enzymes dependent on Ln(3+) but not related to XoxF enzymes may exist, and these so far have not been recognized. Through connecting the recently uncovered genetic divergence and phylogenetic distribution of XoxF-like enzymes and through elucidation of their activities, metal and substrate specificities, along with the biological contexts of respective biochemical pathways, most parsimonious scenarios for their evolution could be uncovered. Generation of such data will firmly establish the role of Ln(3+) in the biochemistry of Life inhabiting this planet. PMID:27357406

  4. Features of the reaction of heterocyclic analogs of chalcone with lanthanide shift reagents

    SciTech Connect

    Turov, A.V.; Khilya, V.P.

    1994-10-01

    The PMR spectra of heterocyclic analogs of 2-hydroxychalcone containing thiazole, benzofuran, triazole, imidazole, benzodioxane, or pyridine rings in the presence of lanthanide shift reagents are studied. It is found that the most effective reagent for modifying the spectra of these compounds is Yb(fod)3. The broadening of the spectra of 2-hydroxy chalcones in the presence of lanthanide shift reagents is explained by the dynamic effects of complex formation. An example is given of the determination of the conformation of molecules of 2-hydroxychalcone by the simultaneous use of lanthanide shift reagents and the homonuclear Overhauser effect. 9 refs., 1 fig., 1 tab.

  5. The separation of lanthanides and actinides in supercritical fluid carbon dioxide

    SciTech Connect

    Mincher, Bruce J.; Wai, Chien M.; Fox, Robert V.; Baek, Donna L.; Yen, Clive; Case, Mary E.

    2015-10-28

    Supercritical fluid carbon dioxide presents an attractive alternative to conventional solvents for recovery of the actinides and lanthanides. Carbon dioxide is a good solvent for fluorine and phosphate-containing ligands, including the traditional tributylphosphate ligand used in process-scale uranium separations. Actinide and lanthanide oxides may even be directly dissolved in carbon dioxide containing the complexes formed between these ligands and mineral acids, obviating the need for large volumes of acids for leaching and dissolution, and the corresponding organic liquid–liquid solvent extraction solutions. As a result, examples of the application of this novel technology for actinide and lanthanide separations are presented.

  6. The interactions between the sterically demanding trimesitylphosphine oxide and trimesityphosphine with scandium and selected lanthanide ions

    NASA Astrophysics Data System (ADS)

    Platt, Andrew W. G.; Singh, Kuldip

    2016-05-01

    The reactions between lanthanide nitrates, Ln(NO3)3 and scandium and lanthanide trifluoromethane sulfonates, Ln(Tf)3 with trimesitylphosphine oxide, Mes3PO show that coordination to the metal ions does not lead to crystalline complexes. Investigation of the reactions by 31-P NMR spectroscopy shows that weak complexes are formed in solution. The crystal structures of Mes3PO·0.5CH3CN (1) and [Mes3PO]3H3O·2CH3CN·Tf (2), formed in the reaction between ScTf3 and Mes3PO, are reported. Trimesitylphosphine, Mes3P, is protonated by scandium and lanthanide trifluoromethane sulfonates and lanthanide nitrates in CD3CN and the structure of [Mes3PH]Cl·HCl·2H2O (3) is reported.

  7. Enhancement of Anion Binding in Lanthanide Optical Sensors

    PubMed Central

    Cable, Morgan L.; Kirby, James P.; Gray, Harry B.; Ponce, Adrian

    2013-01-01

    In the design of molecular sensors, researchers exploit binding interactions that are usually defined in terms of topology and charge complementarity. The formation of complementary arrays of highly cooperative, noncovalent bonding networks facilitates protein-ligand binding, leading to motifs such as the ‘lock-and-key.’ Synthetic molecular sensors often employ metal complexes as key design elements as a way to construct a binding site with the desired shape and charge to achieve target selectivity. In transition metal complexes, coordination number, structure and ligand dynamics are governed primarily by a combination of inner-sphere covalent and outer-sphere noncovalent interactions. These interactions provide a rich variable space that researchers can use to tune structure, stability and dynamics. In contrast, lanthanide(III)-ligand complex formation and ligand-exchange dynamics are dominated by reversible electrostatic and steric interactions, because the unfilled f shell is shielded by the larger, filled d shell. Luminescent lanthanides such as terbium, europium, dysprosium and samarium display many photophysical properties that make them excellent candidates for molecular sensor applications. Complexes of lanthanide ions act as receptors that exhibit a detectable change in metal-based luminescence upon binding of an anion. In our work on sensors for detection of dipicolinate, the unique biomarker of bacterial spores, we discovered that the incorporation of an ancillary ligand (AL) can enhance binding constants of target anions to lanthanide ions by as much as two orders of magnitude. In this Account, we show that selected ALs in lanthanide/anion systems greatly improve sensor performance for medical, planetary science and biodefense applications. We suggest that the observed anion binding enhancement could result from an AL-induced increase in positive charge at the lanthanide ion binding site. This effect depends on lanthanide polarizability, which can

  8. Novel materials based on DNA-CTMA and lanthanide (Ce(3+) , Pr(3+) ).

    PubMed

    Lazar, Cosmina Andreea; Kajzar, François; Mihaly, Maria; Rogozea, Adina Elena; Petcu, Adina Roxana; Olteanu, Nicoleta Liliana; Rau, Ileana

    2016-09-01

    New, deoxyribonucleic acid (DNA) based compounds, functionalized with hexadecyltrimethylammonium chloride (CTMA) and lanthanide hydroxide nanoparticles were synthesized. The spectral measurements suggest that between the DNA-CTMA complex and the lanthanide (III) ions a chemical interaction takes place. The obtained materials exhibit an improved fluorescence efficiency, showing a potential interest for application in photonics, and more particularly, in light emitting devices. © 2016 Wiley Periodicals, Inc. Biopolymers 105: 613-617, 2016. PMID:27120012

  9. Highly Luminescent, Water-Soluble Lanthanide Fluorobenzoates: Syntheses, Structures and Photophysics, Part I: Lanthanide Pentafluorobenzoates.

    PubMed

    Kalyakina, Alena S; Utochnikova, Valentina V; Bushmarinov, Ivan S; Ananyev, Ivan V; Eremenko, Igor L; Volz, Daniel; Rönicke, Franziska; Schepers, Ute; Van Deun, Rik; Trigub, Alexander L; Zubavichus, Yan V; Kuzmina, Natalia P; Bräse, Stefan

    2015-12-01

    Highly luminescent, photostable, and soluble lanthanide pentafluorobenzoates have been synthesized and thoroughly characterized, with a focus on Eu(III) and Tb(III) complexes as visible emitters and Nd(III) , Er(III) , and Yb(III) complexes as infrared emitters. Investigation of the crystal structures of the complexes in powder form and as single crystals by using X-ray diffraction revealed five different structural types, including monomeric, dimeric, and polymeric. The local structure in different solutions was studied by using X-ray absorption spectroscopy. The photoluminescence quantum yields (PLQYs) of terbium and europium complexes were 39 and 15 %, respectively; the latter value was increased almost twice by using the heterometallic complex [Tb0.5 Eu0.5 (pfb)3 (H2 O)] (Hpfb=pentafluorobenzoic acid). Due to the effectively utilized sensitization strategy (pfb)(-) →Tb→Eu, a pure europium luminescence with a PLQY of 29 % was achieved. PMID:26489887

  10. The Partitioning of Americium and the Lanthanides Using Tetrabutyldiglycolamide (TBDGA) in Octanol and in Ionic Liquid Solution

    SciTech Connect

    M.E. Mincher; D.L. Quach; Y.J. Liao; B.J. Mincher; C.M. Wai

    2012-11-01

    Separations among the lanthanides and the separation of Am from the lanthanides remain challenging, and research in this area continues to expand. The separation of adjacent lanthanides is of interest to high-tech industries because individual lanthanides have specialized uses and are in short supply. In nuclear fuel cycle applications Am would be incorporated into fast reactor fuels, yet the lanthanides are not desired. In this work the diamide N,N,N',N'-tetrabutyldiglycolamide (TBDGA) was investigated as a ligand for lanthanide and Am solvent extraction in both molecular and room temperature ionic liquid (RTIL) diluents. The RTIL [C4MIM][Tf2N-] showed very high extraction efficiency for these trivalent metals from low nitric acid concentrations, while the molecular diluent 1-octanol showed high extraction efficiency at high acid concentrations. This was attributed to the extraction of ionic nitrate complexes by the RTIL, whereas 1-octanol extracted neutral nitrate complexes. TBDGA in RTIL did not provide adequate separation factors for Am/lanthanide partitioning, but 1-octanol did show reasonable separation possibilities. Lanthanide intergroup separations appeared to be feasible in both diluents, but with higher separation factors from 1-octanol.

  11. Involvement of lanthanides in the free radicals homeostasis.

    PubMed

    Valcheva-Traykova, Maria; Saso, Luciano; Kostova, Irena

    2014-01-01

    Lanthanides are group of rare-earth elements with growing applications both in the industry and healthcare. Their unique properties impose various possibilities for involvement in electron transfer reactions essential for the cellular survival and health on general. The intensified contact of people with lanthanides and the expanding medicinal applications of their compounds insist more profound knowledge on the involvement in biologically relevant electron transfer reactions. It is well known that the balance between formation and elimination of free radicals in a living body is essential for its health and survival. Any internal or environmental factor that alters this balance alters the homeostasis and this way altering the health status. In the present review, the possibilities of changing the balance between formation and elimination of free radicals, due to introduction of different lanthanides and their complexes with organic ligands, were explored, based on the available information in the literature. It was observed that lanthanides may act either as antioxidants or pro-oxidants, depending on the environment, the nature of the bonding in their compounds, and concentration in the tissues. The opportunities for their application in medicine were related with the abilities to control over their involvement in the overall oxidative status of the body.

  12. Synthesis of novel lanthanide acylpyrazolonato ligands with long aliphatic chains and immobilization of the Tb complex on the surface of silica pre-modified via hydrophobic interactions.

    PubMed

    Pettinari, C; Marchetti, F; Pettinari, R; Belousov, Y A; Taydakov, I V; Krasnobrov, V D; Petukhov, D I; Drozdov, A A

    2015-09-01

    Five new complexes Ln(Q(C17))3(H2O)(Solv) (Ln = Y, Solv = H2O, Ln = Tb, Dy, Sm or Eu, Solv = EtOH) were synthesized with the acylpyrazolonato ligand Q(C17) bearing a long aliphatic C17H35 chain in the acyl moiety, and the crystal structure of Y(Q(C17))3(H2O)2 shows the three aliphatic chains from the coordinated ligands positioned in the same direction, affording plane layers built by Y(Q(C17))3(H2O)2 molecules connected through H-bonding interactions. The layers are stitched to each other like in "hook & loop" tapes. Luminescence of complexes was determined and the complex Tb(Q(C17))3(H2O)(EtOH) was immobilized on the surface of silica preprocessed using a C17H35CONH(CH2)3Si(OEt)3 reagent via hydrophobic interactions of long aliphatic chains. Luminescent properties and micromorphology of the obtained hybrid particles and hybrid films were investigated. Intensive green emission of the complex retains after grafting onto the silica surface. Inclusion of the complex on the surface of silica materials occurs as separate molecules, after the disruption of the H-bonding network present in the crystalline phase of the pure terbium sample.

  13. Control of Lanthanide Coordination Environment: Synthesis, Structure, and Oxygen-Sensitive Luminescence Properties of an Eight-Coordinate Tb(III) Complex.

    PubMed

    Nakai, Hidetaka; Seo, Juncheol; Kitagawa, Kazuhiro; Goto, Takahiro; Nonaka, Kyoshiro; Matsumoto, Takahiro; Ogo, Seiji

    2016-07-01

    Coordination environment of the Tb(3+) ion in oxygen-sensitive luminescent complexes can be successfully controlled through the size of alkyl substituents on ligands {((RMe)ArOH)4cyclen} (R = tBu or Me; cyclen = 1,4,7,10-tetraazacyclododecane); a newly prepared eight-coordinate complex 1(tBu) shows higher oxygen sensitivity (KSV = 17 600) and lower luminescence quantum yield (Φ = 0.67 under N2) than those of the previously reported seven-coordinate analogues 1(Me) and [{((MeMe)ArO)3tacn}Tb(III)(THF)] (KSV = 12 600 and 8300, Φ = 0.91 and 0.91 under N2, respectively; tacn = 1,4,7-triazacyclononane; THF = tetrahydrofuran). The oxygen-sensitive mechanism is discussed on the basis of the photophysical properties of the corresponding Gd(III) complexes. PMID:27326826

  14. Lanthanide(III) complexes of aminoethyl-DO3A as PARACEST contrast agents based on decoordination of the weakly bound amino group.

    PubMed

    Krchová, Tereza; Kotek, Jan; Jirák, Daniel; Havlíčková, Jana; Císařová, Ivana; Hermann, Petr

    2013-11-28

    2-Aminoethyl DOTA analogues with unsubstituted (H3L1), monomethylated (H3L2) and dimethylated (H3L3) amino groups were prepared by improved synthetic procedures. Their solid-state structures exhibit an extensive system of intramolecular hydrogen bonds, which is probably present in solution and leads to the rather high value of the last dissociation constant. The protonation sequence of H3L1 in solution corresponds to that found in the solid state. The stability constants of the H3L1 complexes with La(3+) and Gd(3+) (20.02 and 22.23, respectively) are similar to those of DO3A and the reduction of the pK(A) value of the pendant amino group from 10.51 in the free ligand to 6.06 and 5.83 in the La(3+) and Gd(3+) complexes, respectively, points to coordination of the amino group. It was confirmed in the solid state structure of the [Yb(L1)] complex, where disorder between the SA' and TSA' isomers was found. A similar situation is expected in solution, where a fast equilibration among the isomers hampers the unambiguous determination of the isomer ratio in solution. The PARACEST effect was observed in Eu(III)-H3L1/H3L2 and Yb(III)-H3L1/H3L2 complexes, being dependent on pH in the region of 4.5-7.5 and pH-independent in more alkaline solutions. The decrease of the PARACEST effect parallels with the increasing abundance of the complex protonated species, where the pendant amino group is not coordinating. Surprisingly, a small PARACEST effect was also observed in solutions of Eu(III)/Yb(III)-H3L3 complexes, where the pendant amino group is dimethylated. The effect is detectable in a narrow pH region, where both protonated and deprotonated complex species are present in equilibrium. The data points to the new mechanism of the PARACEST effect, where the slow coordination-decoordination of the pendant amine is coupled with the fast proton exchange between the free amino group and bulk water mediates the magnetization transfer. The pH-dependence of the effect was proved to be

  15. The selectivity of diglycolamide (TODGA) and bis-triazine-bipyridine (BTBP) ligands in actinide/lanthanide complexation and solvent extraction separation - a theoretical approach.

    PubMed

    Narbutt, Jerzy; Wodyński, Artur; Pecul, Magdalena

    2015-02-14

    Theoretical calculations (density functional theory with the scalar relativistic ZORA Hamiltonian) have been performed to obtain the energy and Gibbs free energy of formation of cationic 1 : 3 complexes of americium(iii) and europium(iii) with a tri-O-dentate diglycolamide ligand TEDGA (a model of TODGA extractant), as well as the free energy of their partition between water and an organic diluent. The distribution of electron density over the atoms, bonds, and molecular orbitals was analyzed by means of Mulliken population analysis, the localization procedure of natural bond orbitals, and the Quantum Theory of Atoms-in-Molecules. The stabilities of both [M(TEDGA)(3)](3+) complexes are similar to each other. On the other hand, our recent data for a similar pair of cationic Am/Eu complexes with a softer (HSAB) tetra-N-dentate ligand C2-BTBP show that the [Am(C2-BTBP)(2)](3+) complex is significantly more stable in aqueous solution than its Eu counterpart. The decisive factor stabilizing the Am(3+) complexes over their Eu(3+) analogues is the charge transfer from the ligands, somewhat greater on the 6d(Am(III)) than on 5d(Eu(III)) orbitals. The covalency of M-N bonds in the [M(C2-BTBP)(2)](3+) complexes is greater than that of M-O bonds in [M(TEDGA)(3)](3+), but the latter is not negligible, in particular in the bonds with the oxygen atoms of the amide groups in TEDGA. The analysis of charge distribution over the whole molecules of the complexes shows that the TEDGA molecule is not hard as expected, but a relatively soft Lewis base, only slightly harder than BTBP. This conclusion has been confirmed by the calculation of the chemical hardness of the ligands. Moreover, the comparison of the results of bonding analysis with the calculated energies of complex formation in water and in the gas phase allows us to conclude that the population analysis, QTAIM topological parameters, and SOPT stabilization energy, as well as Wiberg and overlap-weighted NAO indices are the

  16. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements.

  17. Biological toxicity of lanthanide elements on algae.

    PubMed

    Tai, Peidong; Zhao, Qing; Su, Dan; Li, Peijun; Stagnitti, Frank

    2010-08-01

    The biological toxicity of lanthanides on marine monocellular algae was investigated. The specific objective of this research was to establish the relationship between the abundance in the seawater of lanthanides and their biological toxicities on marine monocellular algae. The results showed that all single lanthanides had similar toxic effects on Skeletonema costatum. High concentrations of lanthanides (29.04+/-0.61 micromol L(-1)) resulted in 50% reduction in growth of algae compared to the controls (0 micromol L(-1)) after 96 h (96 h-EC50). The biological toxicity of 13 lanthanides on marine monocellular algae was unrelated with the abundance of different lanthanide elements in nature, and the "Harkins rule" was not appropriate for the lanthanides. A mixed solution that contained equivalent concentrations of each lanthanide element had the same inhibition effect on algae cells as each individual lanthanide element at the same total concentration. This phenomenon is unique compared to the groups of other elements in the periodic table. Hence, we speculate that the monocellular organisms might not be able to sufficiently differentiate between the almost chemically identical lanthanide elements. PMID:20547408

  18. Antioxidation and DNA-binding properties of binuclear lanthanide(III) complexes with a Schiff base ligand derived from 8-hydroxyquinoline-7-carboxaldehyde and benzoylhydrazine.

    PubMed

    Liu, Yongchun; Zhang, Kejun; Wu, Yun; Zhao, Junying; Liu, Jianning

    2012-08-01

    8-Hydroxyquinoline-7-carboxaldehyde (8-HQ-7-CA), Schiff-base ligand 8-hydroxyquinoline-7-carboxaldehyde benzoylhydrazone, and binuclear complexes [LnL(NO(3))(H(2)O)(2)](2) were prepared from the ligand and equivalent molar amounts of Ln(NO(3))·6H(2)O (Ln=La(3+), Nd(3+), Sm(3+), Eu(3+), Gd(3+), Dy(3+), Ho(3+), Er(3+), Yb(3+), resp.). Ligand acts as dibasic tetradentates, binding to Ln(III) through the phenolate O-atom, N-atom of quinolinato unit, and C=N and -O-C=N- groups of the benzoylhydrazine side chain. Dimerization of this monomeric unit occurs through the phenolate O-atoms leading to a central four-membered (LnO)(2) ring. Ligand and all of the Ln(III) complexes can strongly bind to CT-DNA through intercalation with the binding constants at 10(5)-10(6) M(-1). Moreover, ligand and all of the Ln(III) complexes have strong abilities of scavenging effects for hydroxyl (HO·) radicals. Both the antioxidation and DNA-binding properties of Ln(III) complexes are much better than that of ligand.

  19. Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides.

    PubMed

    Zhang, Qingnan; Hu, Shu-Xian; Qu, Hui; Su, Jing; Wang, Guanjun; Lu, Jun-Bo; Chen, Mohua; Zhou, Mingfei; Li, Jun

    2016-06-01

    The chemistry of lanthanides (Ln=La-Lu) is dominated by the low-valent +3 or +2 oxidation state because of the chemical inertness of the valence 4f electrons. The highest known oxidation state of the whole lanthanide series is +4 for Ce, Pr, Nd, Tb, and Dy. We report the formation of the lanthanide oxide species PrO4 and PrO2 (+) complexes in the gas phase and in a solid noble-gas matrix. Combined infrared spectroscopic and advanced quantum chemistry studies show that these species have the unprecedented Pr(V) oxidation state, thus demonstrating that the pentavalent state is viable for lanthanide elements in a suitable coordination environment.

  20. Trivalent actinide and lanthanide separations using tetraalkyldiglycolamides (TCnDGA) in molecular and ionic liquid diluents

    SciTech Connect

    Bruce J. Mincher; Robert V. Fox; Mary E. Mincher; Chien M. Wai

    2014-09-01

    The use of the diglycolamide, tetrabutyldiglycolamide was investigated for intergroup separations of the lanthanides, focusing especially on those lanthanides (Y, Ce, Eu, Tb, Dy, Er, and Yb) found in lighting phosphors. Tetrabutyldiglycolamide extraction efficiency for the lanthanides varied depending on whether the diluent was the conventional molecular diluent 1-octanol, the ionic liquid 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)-imide, or a mixture of the two. This was attributed to extraction of either neutral, cationic or anionic lanthanide metal complexes with nitrate ion. Based on the batch contact solvent extraction results measured here, a series of extractions providing product streams containing separated Y, Ce, Eu, Tb/Dy, and Er/Yb are proposed.

  1. Pentavalent Lanthanide Compounds: Formation and Characterization of Praseodymium(V) Oxides.

    PubMed

    Zhang, Qingnan; Hu, Shu-Xian; Qu, Hui; Su, Jing; Wang, Guanjun; Lu, Jun-Bo; Chen, Mohua; Zhou, Mingfei; Li, Jun

    2016-06-01

    The chemistry of lanthanides (Ln=La-Lu) is dominated by the low-valent +3 or +2 oxidation state because of the chemical inertness of the valence 4f electrons. The highest known oxidation state of the whole lanthanide series is +4 for Ce, Pr, Nd, Tb, and Dy. We report the formation of the lanthanide oxide species PrO4 and PrO2 (+) complexes in the gas phase and in a solid noble-gas matrix. Combined infrared spectroscopic and advanced quantum chemistry studies show that these species have the unprecedented Pr(V) oxidation state, thus demonstrating that the pentavalent state is viable for lanthanide elements in a suitable coordination environment. PMID:27100273

  2. Selectivity enhancement of Arsenazo(III) reagent towards heavier lanthanides using polyaminocarboxylic acids: A spectrophotometric study

    NASA Astrophysics Data System (ADS)

    Matharu, Komal; Mittal, Susheel K.; Ashok Kumar, S. K.; Sahoo, Suban K.

    2015-06-01

    A new study has been conducted to quantify lanthanide(III) ions using Arsenazo III-polyaminocarboxylic acid (PACA) system. The study disclosed two different analytically important information: (i) λmax of lanthanide-Arsenazo III complexes for lighter lanthanides like Ce(III) and Nd(III) did not shift from its original position on addition of PACA and (ii) for heavier lanthanides like Dy(III), Tm(III) and Lu(III) a new λmax at 538 nm was observed, while wavelengths at 610 nm and 654 nm were disappeared in presence of ethylenediaminetertracetic acid (EDTA) and trans-1,2-Diaminocyclohexane-N,N,N‧,N‧-tetraacetic acid (DCTA), further the intensity of peak decreased with increase in lanthanide(III) ion concentration. Effect of ethylene glycol-bis(2-aminoethylether)-N,N,N‧,N‧-tetraacetic acid (EGTA) and N-(2-hydroxyethyl) ethylenediamine-N,N‧,N‧-triacetic acid (EDTA-OH) on Arsenzo(III)-Ln(III) complex is very weak and there is no analytically importance of such interaction. Moreover, this work confirms that Nd(III) and heavy lanthanides can be successfully determined with high accuracy in the working range of concentration of these metal ions.

  3. Extraction and coordination studies of a carbonyl-phosphine oxide scorpionate ligand with uranyl and lanthanide(III) nitrates: structural, spectroscopic and DFT characterization of the complexes.

    PubMed

    Matveeva, Anna G; Vologzhanina, Anna V; Goryunov, Evgenii I; Aysin, Rinat R; Pasechnik, Margarita P; Matveev, Sergey V; Godovikov, Ivan A; Safiulina, Alfiya M; Brel, Valery K

    2016-03-28

    Hybrid scorpionate ligand (OPPh2)2CHCH2C(O)Me (L) was synthesized and characterized by spectroscopic methods and X-ray diffraction. The selected coordination chemistry of L with UO2(NO3)2 and Ln(NO3)3 (Ln = La, Nd, Lu) has been evaluated. The isolated mono- and binuclear complexes, namely, [UO2(NO3)2L] (1), [{UO2(NO3)L}2(μ2-O2)]·EtOH (2), [La(NO3)3L2]·2.33MeCN (3), [Nd(NO3)3L2]·3MeCN (4), [Nd(NO3)2L2]+·(NO3)−·EtOH (5) and [Lu(NO3)3L2] (6) have been characterized by IR spectroscopy and elemental analysis. Single-crystal X-ray structures have been determined for complexes 1-5. Intramolecular intraligand π-stacking interactions between two phenyl fragments of the coordinated ligand(s) were observed in all complexes 1-5. The π-stacking interaction energy was estimated from Bader's AIM theory calculations performed at the DFT level. Solution properties have been examined using IR and multinuclear ((1)H, (13)C, and (31)P) NMR spectroscopy in CD3CN and CDCl3. Coordination modes of L vary with the coordination polyhedron of the metal and solvent nature showing many coordination modes: P(O),P(O), P(O),P(O),C(O), P(O),C(O), and P(O). Preliminary extraction studies of U(VI) and Ln(III) (Ln = La, Nd, Ho, Yb) from 3.75 M HNO3 into CHCl3 show that scorpionate L extracts f-block elements (especially uranium) better than its unmodified prototype (OPPh2)2CH2.

  4. Trivalent lanthanide ions do not cleave RNA in DNA-RNA hybrids

    SciTech Connect

    Kolasa, K.A.; Morrow, J.R.; Sharma, A.P. )

    1993-09-15

    Lanthanide(III) complexes rapidly catalyze cleavage of single-stranded RNA. RNA cleavage by lanthanide complexes is, however, dependent on RNA structure. A DNA-RNA hybrid formed by annealing a complementary oligodeoxynucleotide to t-RNA[sup phe] is found to be inert to cleavage by a europium(III) hexadentate Schiff base complex and by Eu(CO[sub 2]CH[sub 3])[sub 3]. Because DNA-RNA hybrids are important structures in antisense oligonucleotide strategies, these results may influence the design of antisense oligonucleotides with attached metal complex cleaving agents.

  5. Investigation of Gravity Lanthanide Separation Chemistry

    SciTech Connect

    Payne, Rosara F.; Schulte, Shannon M.; Douglas, Matthew; Friese, Judah I.; Farmer, Orville T.; Finn, Erin C.

    2011-03-01

    Lanthanides are common fission products and the ability to separate and quantify these elements is critical to rapid radiochemistry applications. Published lanthanide separations using Eichrom Ln Spec resin utilize an HCl gradient. Here it is shown that the efficacy and resolution of the separation is improved when a nitric acid gradient is used instead. The described method allows parallel processing of many samples in 1.5 hours followed by 60 minute counting for quantification of 9 isotopes of 7 lanthanide elements.

  6. Enhancement of lanthanide evaporation by complexation: Dysprosium tri-iodide mixed with indium iodide and thulium tri-iodide mixed with thallium iodide

    SciTech Connect

    Curry, J. J.; Henins, A.; Hardis, J. E.; Estupiñán, E. G.; Lapatovich, W. P.; Shastri, S. D.

    2013-09-28

    The vapors in equilibrium with condensates of DyI{sub 3}, DyI{sub 3}/InI, TmI{sub 3}, and TmI{sub 3}/TlI were observed over the temperature range from 900 K to 1400 K using x-ray induced fluorescence. The total densities of each element (Dy, Tm, In, Tl, and I) in the vapor, summed over all atomic and molecular species, were determined. Dramatic enhancements in the total vapor densities of Dy and Tm were observed in the vapors over DyI{sub 3}/InI and TmI{sub 3}/TlI as compared to the vapors over pure DyI{sub 3} and pure TmI{sub 3}, respectively. An enhancement factor exceeding 10 was observed for Dy at T≈ 1020 K, decreasing to 0 at T≈ 1250 K. An enhancement factor exceeding 20 was observed for Tm at T≈ 1040 K, decreasing to 0 at T≈ 1300 K. Such enhancements are expected from the formation of the vapor-phase hetero-complexes DyInI{sub 4} and TmTlI{sub 4}. Numerical simulations of the thermo-chemical equilibrium suggest the importance of additional complexes in liquid phases. A description of the measurement technique is given. Improvements in the absolute calibration lead to an approximately 40% correction to previously reported preliminary results [J. J. Curry et al., Chem. Phys. Lett. 507, 52 (2011); Appl. Phys. Lett. 100, 083505 (2012)].

  7. Fracture-resistant lanthanide scintillators

    DOEpatents

    Doty, F. Patrick

    2011-01-04

    Lanthanide halide alloys have recently enabled scintillating gamma ray spectrometers comparable to room temperature semiconductors (<3% FWHM energy resolutions at 662 keV). However brittle fracture of these materials upon cooling hinders the growth of large volume crystals. Efforts to improve the strength through non-lanthanide alloy substitution, while preserving scintillation, have been demonstrated. Isovalent alloys having nominal compositions of comprising Al, Ga, Sc, Y, and In dopants as well as aliovalent alloys comprising Ca, Sr, Zr, Hf, Zn, and Pb dopants were prepared. All of these alloys exhibit bright fluorescence under UV excitation, with varying shifts in the spectral peaks and intensities relative to pure CeBr.sub.3. Further, these alloys scintillate when coupled to a photomultiplier tube (PMT) and exposed to .sup.137Cs gamma rays.

  8. Employment of methyl 2-pyridyl ketone oxime in 3d/4f-metal chemistry: dinuclear nickel(II)/lanthanide(III) species and complexes containing the metals in separate ions.

    PubMed

    Polyzou, Christina D; Nikolaou, Helen; Papatriantafyllopoulou, Constantina; Psycharis, Vassilis; Terzis, Aris; Raptopoulou, Catherine P; Escuer, Albert; Perlepes, Spyros P

    2012-11-28

    The use of methyl 2-pyridyl ketone oxime (mpkoH) for the synthesis of Ni(II)/Ln(III) (Ln = lanthanide) complexes, using "one-pot" reactions in the absence of an external base, is described. Depending on the reaction and crystallization conditions employed, two families of complexes have been obtained. The first family consists of true heterometallic species and involves complexes [NiLn(mpko)(3)(mpkoH)(3)](ClO(4))(2), where Ln = Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho and Er. The second family contains the pseudo heterometallic complexes [Ni(mpkoH)(3)](2)[Ln(NO(3))(6)](ClO(4)), where Ln = La, Ce, Pr, Nd and Sm. The crystal structures of [NiCe(mpko)(3)(mpkoH)(3)](ClO(4))(2) (1), [NiDy(mpko)(3)(mpkoH)(3)](ClO(4))(2) (8) and [Ni(mpkoH)(3)](2)[La(NO(3))(6)](ClO(4)) (11) have been determined by single-crystal, X-ray crystallography. Complexes 1·1.2MeOH·0.6H(2)O and 8·1.2MeOH·0.6H(2)O crystallise in the monoclinic space group P2(1)/a and are isomorphous; there are two crystallographically independent cations in the unit cell, but their interatomic distances and angles differ little. The Ni(II) and Ln(III) ions are bridged by three oximate groups belonging to the η(1):η(1):η(1):μ mpko(-) ligands. The Ni(II) centre is octahedrally coordinated by the six nitrogen atoms of the mpko(-) ligands in a facial arrangement. The Ln(III) centre is bound to an (O(oximate))(3)N(6) set of donor atoms, the nitrogen atoms belonging to the three N,N'-bidentate chelating mpkoH ligands. The stereochemistry of the Ln(III) atoms has been evaluated by means of continuous shape measures (CShM). The two crystallographically independent Ce(III) atoms in 1 have tricapped trigonal prismatic and capped square antiprismatic coordination geometries, while the polyhedra of the Dy(III) atoms in 8 are both close to a tricapped trigonal prism. The octahedral Ni(II) atoms in 11 are both facially bound to a N(6) set of donor atoms from three N,N'-bidentate chelating mpkoH ligands, while the 12-coordinate

  9. Lanthanide mixed ligand chelates for DNA profiling and latent fingerprint detection

    NASA Astrophysics Data System (ADS)

    Menzel, E. R.; Allred, Clay

    1997-02-01

    It is our aim to develop a universally applicable latent fingerprint detection method using lanthanide (rare-earth) complexes as a source of luminescence. Use of these lanthanide complexes offers advantages on several fronts, including benefits from large Stokes shifts, long luminescence lifetimes, narrow emissions, ability of sequential assembly of complexes, and chemical variability of the ligands. Proper exploitation of these advantages would lead to a latent fingerprint detection method superior to any currently available. These same characteristics also lend themselves to many of the problems associated with DNA processing in the forensic science context.

  10. Tuning the self-assembly of lanthanide triple stranded heterobimetallic helicates by ligand design.

    PubMed

    Jensen, Thomas B; Scopelliti, Rosario; Bünzli, Jean-Claude G

    2008-02-28

    The heterobitopic ligands L(AB4) and L(AB5) have been designed and synthesised with the ultimate aim of self-assembling dual-function lanthanide complexes containing either a magnetic and a luminescent probe or two luminescent probes emitting at different wavelengths. They react with lanthanide ions to form complexes of composition [Ln(2)(L(ABX))(3)](6+) of which three (X = 4; Ln = Pr, Nd, Sm) have been isolated and characterised by means of X-ray diffraction. The unit cells contain triple-stranded helicates in which the three ligand strands are wrapped tightly around the two lanthanide ions. In acetonitrile solution the ligands form not only homobimetallic, but also heterobimetallic complexes of composition [Ln(1)Ln(2)(L(ABX))(3)](6+) when reacted with a pair of different lanthanide ions. The yield of heterobimetallic complexes is analyzed in terms of both the difference in ionic radii of the lanthanide ions and of the inherent tendency of the ligands to form high percentages of head-head-head (HHH) helicates in which all three ligand strands are oriented in the same direction with respect to the Ln-Ln vector. The latter is very sensitive to slight modifications of the tridentate coordinating units. PMID:18274683

  11. Advancing the scientific basis of trivalent actinide-lanthanide separations

    SciTech Connect

    Nash, K.L.

    2013-07-01

    For advanced fuel cycles designed to support transmutation of transplutonium actinides, several options have been demonstrated for process-scale aqueous separations for U, Np, Pu management and for partitioning of trivalent actinides and fission product lanthanides away from other fission products. The more difficult mutual separation of Am/Cm from La-Tb remains the subject of considerable fundamental and applied research. The chemical separations literature teaches that the most productive alternatives to pursue are those based on ligand donor atoms less electronegative than O, specifically N- and S-containing complexants and chloride ion (Cl{sup -}). These 'soft-donor' atoms have exhibited usable selectivity in their bonding interactions with trivalent actinides relative to lanthanides. In this report, selected features of soft donor reagent design, characterization and application development will be discussed. The roles of thiocyanate, aminopoly-carboxylic acids and lactate in separation processes are detailed. (authors)

  12. A TRUEX-based separation of americium from the lanthanides

    SciTech Connect

    Bruce J. Mincher; Nicholas C. Schmitt; Mary E. Case

    2011-03-01

    Abstract: The inextractability of the actinide AnO2+ ions in the TRUEX process suggests the possibility of a separation of americium from the lanthanides using oxidation to Am(V). The only current method for the direct oxidation of americium to Am(V) in strongly acidic media is with sodium bismuthate. We prepared Am(V) over a wide range of nitric acid concentrations and investigated its solvent extraction behavior for comparison to europium. While a separation is achievable in principal, the presence of macro amounts of cerium competes for the sparingly soluble oxidant and the oxidant itself competes for CMPO complexation. These factors conspire to reduce the Eu/Am separation factor from ~40 using tracer solutions to ~5 for extractions from first cycle raffinate simulant solution. To separate pentavalent americium directly from the lanthanides using the TRUEX process, an alternative oxidizing agent will be necessary.

  13. Citrate based ``TALSPEAK`` lanthanide-actinide separation process

    SciTech Connect

    Del Cul, G.D.; Bond, W.D.; Toth, L.M.; Davis, G.D.; Dai, S.; Metcalf, D.H.

    1994-09-01

    The potential hazard posed to future generations by long-lived radionuclides such as the transuranic elements (TRU) is perceived as a major problem associated with the use of nuclear power. TRU wastes have to remain isolated from the environment for ``geological`` periods of time. The costs of building, maintaining, and operating a ``geological TRU repository`` can be very high. Therefore, there are significant economical advantages in segregating the relatively low volume of TRU wastes from other nuclear wastes. The chemical behavior of lanthanides and actinides, 4f and 5f elements respectively, is rather similar. As a consequence, the separation of these two groups is difficult. The ``TALSPEAK`` process (Trivalent Actinide Lanthanide Separations by Phosphorus-reagent Extraction from Aqueous Complexes) is one of the few means available to separate the trivalent actinides from the lanthanides. The method is based on the preferential complexation of the trivalent actinides by an aminopolyacetic acid. Cold experiments showed that by using citric acid the deleterious effects produced by impurities such as zirconium are greatly reduced.

  14. Role of the deposition temperature on the self-assembly of the non-planar molecule benzene-1,3,5-triphosphonic acid (BTP) at the liquid-solid interface.

    PubMed

    Nguyen, Doan Chau Yen; Smykalla, Lars; Nguyen, Thi Ngoc Ha; Mehring, Michael; Hietschold, Michael

    2016-09-21

    Benzene-1,3,5-triphosphonic acid (BTP) contains three non-planar phosphonic acid groups which enable three-dimensional hydrogen bonding. Because of these versatile 3D functional groups, BTP is an interesting intermediate to design both 2D and 3D supramolecular hydrogen-bonded architectures and organic-inorganic hybrid frameworks. However, the adsorption of BTP has surprisingly not been the subject of scanning tunneling microscopy (STM) investigations so far. Here a STM study of the adsorption pattern of BTP as obtained from deposition out of a solution in undecanol on an interface to highly-oriented pyrolytic graphite (HOPG) is presented. Furthermore, the influence of the substrate temperature during the deposition from solution on the self-assembly is investigated. High-resolution STM images reveal that the BTB molecules usually form various structures by co-adsorption with undecanol and that the BTP molecules as parts of self-assembled aggregates adsorb with their benzene ring planes tilted with respect to the substrate plane. The specific supramolecular pattern and the 2D packing density of BTP can be precisely tuned by adjusting the initial substrate temperature during deposition. The experimental results are compared to corresponding model structures obtained from semi-empirical simulations and explained by the influence of temperature on the concentration at the solution-solid interface and the kinetics of the self-assembly process. Based on these results, the control of the deposition substrate temperature has been proven to be a versatile tool to control the polymorphism of molecular patterns deposited out of solutions. PMID:27530556

  15. Role of the deposition temperature on the self-assembly of the non-planar molecule benzene-1,3,5-triphosphonic acid (BTP) at the liquid-solid interface.

    PubMed

    Nguyen, Doan Chau Yen; Smykalla, Lars; Nguyen, Thi Ngoc Ha; Mehring, Michael; Hietschold, Michael

    2016-09-21

    Benzene-1,3,5-triphosphonic acid (BTP) contains three non-planar phosphonic acid groups which enable three-dimensional hydrogen bonding. Because of these versatile 3D functional groups, BTP is an interesting intermediate to design both 2D and 3D supramolecular hydrogen-bonded architectures and organic-inorganic hybrid frameworks. However, the adsorption of BTP has surprisingly not been the subject of scanning tunneling microscopy (STM) investigations so far. Here a STM study of the adsorption pattern of BTP as obtained from deposition out of a solution in undecanol on an interface to highly-oriented pyrolytic graphite (HOPG) is presented. Furthermore, the influence of the substrate temperature during the deposition from solution on the self-assembly is investigated. High-resolution STM images reveal that the BTB molecules usually form various structures by co-adsorption with undecanol and that the BTP molecules as parts of self-assembled aggregates adsorb with their benzene ring planes tilted with respect to the substrate plane. The specific supramolecular pattern and the 2D packing density of BTP can be precisely tuned by adjusting the initial substrate temperature during deposition. The experimental results are compared to corresponding model structures obtained from semi-empirical simulations and explained by the influence of temperature on the concentration at the solution-solid interface and the kinetics of the self-assembly process. Based on these results, the control of the deposition substrate temperature has been proven to be a versatile tool to control the polymorphism of molecular patterns deposited out of solutions.

  16. Computing UV/vis spectra using a combined molecular dynamics and quantum chemistry approach: bis-triazin-pyridine (BTP) ligands studied in solution.

    PubMed

    Höfener, Sebastian; Trumm, Michael; Koke, Carsten; Heuser, Johannes; Ekström, Ulf; Skerencak-Frech, Andrej; Schimmelpfennig, Bernd; Panak, Petra J

    2016-03-21

    We report a combined computational and experimental study to investigate the UV/vis spectra of 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridine (BTP) ligands in solution. In order to study molecules in solution using theoretical methods, force-field parameters for the ligand-water interaction are adjusted to ab initio quantum chemical calculations. Based on these parameters, molecular dynamics (MD) simulations are carried out from which snapshots are extracted as input to quantum chemical excitation-energy calculations to obtain UV/vis spectra of BTP ligands in solution using time-dependent density functional theory (TDDFT) employing the Tamm-Dancoff approximation (TDA). The range-separated CAM-B3LYP functional is used to avoid large errors for charge-transfer states occurring in the electronic spectra. In order to study environment effects with theoretical methods, the frozen-density embedding scheme is applied. This computational procedure allows to obtain electronic spectra calculated at the (range-separated) DFT level of theory in solution, revealing solvatochromic shifts upon solvation of up to about 0.6 eV. Comparison to experimental data shows a significantly improved agreement compared to vacuum calculations and enables the analysis of relevant excitations for the line shape in solution. PMID:26907588

  17. Computing UV/vis spectra using a combined molecular dynamics and quantum chemistry approach: bis-triazin-pyridine (BTP) ligands studied in solution.

    PubMed

    Höfener, Sebastian; Trumm, Michael; Koke, Carsten; Heuser, Johannes; Ekström, Ulf; Skerencak-Frech, Andrej; Schimmelpfennig, Bernd; Panak, Petra J

    2016-03-21

    We report a combined computational and experimental study to investigate the UV/vis spectra of 2,6-bis(5,6-dialkyl-1,2,4-triazin-3-yl)pyridine (BTP) ligands in solution. In order to study molecules in solution using theoretical methods, force-field parameters for the ligand-water interaction are adjusted to ab initio quantum chemical calculations. Based on these parameters, molecular dynamics (MD) simulations are carried out from which snapshots are extracted as input to quantum chemical excitation-energy calculations to obtain UV/vis spectra of BTP ligands in solution using time-dependent density functional theory (TDDFT) employing the Tamm-Dancoff approximation (TDA). The range-separated CAM-B3LYP functional is used to avoid large errors for charge-transfer states occurring in the electronic spectra. In order to study environment effects with theoretical methods, the frozen-density embedding scheme is applied. This computational procedure allows to obtain electronic spectra calculated at the (range-separated) DFT level of theory in solution, revealing solvatochromic shifts upon solvation of up to about 0.6 eV. Comparison to experimental data shows a significantly improved agreement compared to vacuum calculations and enables the analysis of relevant excitations for the line shape in solution.

  18. Metal-ligand interaction of lanthanides with coumarin derivatives. Part I. Complexation of 3-(1-aminoethylidene)-2H-chromene-2,4(3H)-dione with La(III), Ce(III), Nd(III) and Ho(III).

    PubMed

    Swiatek, Mirosława; Kufelnicki, Aleksander

    2012-01-01

    Solutions of lanthanum(III), cerium(III), neodymium(III) and holmium(III) nitrates with 3-(1-aminoethylidene)-2H-chromene-2,4(3H)-dione (1) in 10% v/v dioxane-water medium were used. Coordination modes of 1 with the selected lanthanides have been examined. Hydroxo-complexes with deprotonated water molecules from the inner coordination sphere have been stated in basic medium. Stability constants of the forming complex species were determined by potentiometric titrations using Superquad and Hyperquad2003 programs. The most stable complexes are formed with La(III). The UV-Vis spectra of the Nd(III)-1 system confirmed the L:M = 1:1 stoichiometry evaluated potentiometrically.

  19. Separation of Lanthanide Ions with Kläui Ligand Resin

    SciTech Connect

    Granger, Trinity D.; Henry, Victoria A.; Latesky, Stanley

    2007-07-01

    Separation and pre-concentration of the desired analyte is often a critical step in many radioanalytical methods. Current procedures for separating and concentrating analytes for detection are complex, and can be both expensive and time consuming. Therefore, the purpose of this research is to develop an alternative method of separating lanthanide ions through the use of an extraction chromatography resin containing a Klaui ligand salt. This research is a continuation of a concerted effort to develop new methods of detecting small concentrations of radionuclides and lanthanides using Klaui ligands. The Klaui ligands, C5Me5Co(OP(OR)2)3- (R=Me, Et, n-Pr) (LOR-), have unique affinity for lanthanide and actinide ions in the presence of competing metal ions. The use of 1 wt% NaLOR (R=Et or n-Pr) adsorbed onto resin support has been shown to extract lanthanide ions from aqueous nitric acid solutions of different concentrations. In order to further evaluate the utility of these materials in radiochemical separation, the selectivity of the resins for the different lanthanide ions was examined by measuring the distribution coefficients (Kd) for a series of lanthanides over a range of solution conditions. Based on prior research with actinide ions, it was hypothesized that the lanthanide ions would bond strongly with the Klaui ligands. The success of this research is important, because it will assist in expanding and improving current automated radiochemical methods, which will decrease the cost of developing and implementing radiochemical methods. To date, Kd values have been determined for Eu+3, Nd+3 and Pr+3 under varying nitric acid (HNO3) concentration, using a resin consisting of 1.0 wt% NaLOPr on Amberlite XAD-7HP. The dependence of the Kd values for Eu+3 has also been examined as a function of the ligand-to-europium ratio and the nitrate concentration. Decreasing Kd values were obtained upon increasing the nitric acid concentration, indicating protonation of the

  20. Method of loading organic materials with group III plus lanthanide and actinide elements

    DOEpatents

    Bell, Zane W.; Huei-Ho, Chuen; Brown, Gilbert M.; Hurlbut, Charles

    2003-04-08

    Disclosed is a composition of matter comprising a tributyl phosphate complex of a group 3, lanthanide, actinide, or group 13 salt in an organic carrier and a method of making the complex. These materials are suitable for use in solid or liquid organic scintillators, as in x-ray absorption standards, x-ray fluorescence standards, and neutron detector calibration standards.

  1. Separation of actinides from lanthanides

    DOEpatents

    Smith, Barbara F.; Jarvinen, Gordon D.; Ryan, Robert R.

    1989-01-01

    An organic extracting solution and an extraction method useful for separating elements of the actinide series of the periodic table from elements of the lanthanide series, where both are in trivalent form. The extracting solution consists of a primary ligand and a secondary ligand, preferably in an organic solvent. The primary ligand is a substituted monothio-1,3-dicarbonyl, which includes a substituted 4-acyl-2-pyrazolin-5-thione, such as 4-benzoyl-2,4-dihydro-5-methyl-2-phenyl-3H-pyrazol-3-thione (BMPPT). The secondary ligand is a substituted phosphine oxide, such as trioctylphosphine oxide (TOPO).

  2. Enhanced Luminescence of Lanthanides: Determination of Europium by Enhanced Luminescence

    NASA Astrophysics Data System (ADS)

    Jenkins, Amanda L.; Murray, George M.

    1998-02-01

    An experiment has been developed to teach the principles of molecular luminescence spectroscopy. This laboratory experiment is designed for upper-level undergraduates as a less toxic alternative to current fluorescence experiments. It combines elements of physical and inorganic as well as analytical chemistry. The experiment can be performed on a variety of rudimentary fluorescence instrumentation and still give good analytical figures of merit. The object of the experiment is to measure the luminescent enhancement that is achieved when a lanthanide such as Eu(III) or Tb(III) is complexed with appropriate organic ligands, in this case 2,6 pyridinedicarboxylic acid. The importance of pH on metal ion coordination is also explored via luminescence intensity. This approach provides several advantages over current luminescence experiments. These advantages include limited toxicity and flammability of the chemicals involved, a large luminescence linear dynamic range, and low detection limits (parts per trillion). These low detection limits, achieved using modest equipment, allow the determination of the europium concentration in a variety of samples, such as tap water. The narrow lanthanide luminescent bands also permit incorporation of qualitative analysis of a mixture of lanthanides.

  3. Complexation of Cm(III) and Eu(III) with a hydrophilic 2,6-bis(1,2,4-triazin-3-yl)-pyridine studied by time-resolved laser fluorescence spectroscopy.

    PubMed

    Ruff, Christian M; Müllich, Udo; Geist, Andreas; Panak, Petra J

    2012-12-28

    The complexation of Cm(III) and Eu(III) with 2,6-bis(5,6-di(sulfophenyl)-1,2,4-triazin-3-yl)pyridine (aq-BTP) is studied in water at pH 3.0 applying time-resolved laser fluorescence spectroscopy. With increasing ligand concentration [M(H(2)O)(9-3n)(aq-BTP)(n)] (M = Cm(III)/Eu(III), n = 1, 2, 3) complex species are spectroscopically identified. The conditional stability constants of the M(III) 1 : 3 complex species with aq-BTP are log β(03) = 12.2 for Cm(III) and log β(03) = 10.2 for Eu(III). The complexation reaction is enthalpy- and entropy-driven for both metal ions, while the enthalpy change ΔH(03) is 9.7 kJ mol(-1) more negative for Cm(III); changes in ΔS(03) are marginal. The difference in ΔG(03) of -12.7 kJ mol(-1) between the formation of the [M(aq-BTP)(3)] complexes agrees with aq-BTP's selectivity in liquid-liquid extraction studies. PMID:23018544

  4. Complexation of Cm(III) and Eu(III) with a hydrophilic 2,6-bis(1,2,4-triazin-3-yl)-pyridine studied by time-resolved laser fluorescence spectroscopy.

    PubMed

    Ruff, Christian M; Müllich, Udo; Geist, Andreas; Panak, Petra J

    2012-12-28

    The complexation of Cm(III) and Eu(III) with 2,6-bis(5,6-di(sulfophenyl)-1,2,4-triazin-3-yl)pyridine (aq-BTP) is studied in water at pH 3.0 applying time-resolved laser fluorescence spectroscopy. With increasing ligand concentration [M(H(2)O)(9-3n)(aq-BTP)(n)] (M = Cm(III)/Eu(III), n = 1, 2, 3) complex species are spectroscopically identified. The conditional stability constants of the M(III) 1 : 3 complex species with aq-BTP are log β(03) = 12.2 for Cm(III) and log β(03) = 10.2 for Eu(III). The complexation reaction is enthalpy- and entropy-driven for both metal ions, while the enthalpy change ΔH(03) is 9.7 kJ mol(-1) more negative for Cm(III); changes in ΔS(03) are marginal. The difference in ΔG(03) of -12.7 kJ mol(-1) between the formation of the [M(aq-BTP)(3)] complexes agrees with aq-BTP's selectivity in liquid-liquid extraction studies.

  5. Selective extraction of trivalent actinides from lanthanides with dithiophosphinic acids and tributylphosphate

    SciTech Connect

    Jarvinen, G.; Barrans, R.; Schroeder, N.; Wade, K.; Jones, M.; Smith, B.F.; Mills, J.; Howard, G.; Freiser, H.; Muralidharan, S.

    1995-01-01

    A variety of chemical systems have been developed to separate trivalent actinides from lanthanides based on the slightly stronger complexation of the trivalent actinides with ligands that contain soft donor atoms. The greater stability of the actinide complexes in these systems has often been attributed to a slightly greater covalent bonding component for the actinide ions relative to the lanthanide ions. The authors have investigated several synergistic extraction systems that use ligands with a combination of oxygen and sulfur donor atoms that achieve a good group separation of the trivalent actinides and lanthanides. For example, the combination of dicyclohexyldithiophosphinic acid and tributylphosphate has shown separation factors of up to 800 for americium over europium in a single extraction stage. Such systems could find application in advanced partitioning schemes for nuclear waste.

  6. Prototypes of Lanthanide(III) Agents Responsive to Enzymatic Activities in Three Complementary Imaging Modalities: Visible/Near-Infrared Luminescence, PARACEST-, and T1-MRI.

    PubMed

    He, Jiefang; Bonnet, Célia S; Eliseeva, Svetlana V; Lacerda, Sara; Chauvin, Thomas; Retailleau, Pascal; Szeremeta, Frederic; Badet, Bernard; Petoud, Stéphane; Tóth, Éva; Durand, Philippe

    2016-03-01

    We report first prototypes of responsive lanthanide(III) complexes that can be monitored independently in three complementary imaging modalities. Through the appropriate choice of lanthanide(III) cations, the same reactive ligand can be used to form complexes providing detection by (i) visible (Tb(3+)) and near-infrared (Yb(3+)) luminescence, (ii) PARACEST- (Tb(3+), Yb(3+)), or (iii) T1-weighted (Gd(3+)) MRI. The use of lanthanide(III) ions of different natures for these imaging modalities induces only a minor change in the structure of complexes that are therefore expected to have a single biodistribution and cytotoxicity.

  7. Lanthanide ion (III) complexes of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP8−) for dual biosensing of pH with CEST (chemical exchange saturation transfer) and BIRDS (biosensor imaging of redundant deviation in shifts)

    PubMed Central

    Huang, Yuegao; Coman, Daniel; Ali, Meser M.; Hyder, Fahmeed

    2014-01-01

    Relaxivity based magnetic resonance of phosphonated ligands chelated with gadolinium (Gd3+) shows promise for pH imaging. However instead of monitoring the paramagnetic effect of lanthanide complexes on the relaxivity of water protons, biosensor (or molecular) imaging with magnetic resonance is also possible by detecting either the non-exchangeable or the exchangeable protons on the lanthanide complexes themselves. The non-exchangeable protons (e.g., –CHx, where 3≥x≥1) are detected using a three-dimensional chemical shift imaging method called Biosensor Imaging of Redundant Deviation in Shifts (BIRDS), whereas the exchangeable protons (e.g., –OH or –NHy, where 2≥y≥1) are measured with Chemical Exchange Saturation Transfer (CEST) contrast. Here we tested the feasibility of BIRDS and CEST for pH imaging of 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraaminophosphonate (DOTA-4AmP8−) chelated with thulium (Tm3+) and ytterbium (Yb3+). BIRDS and CEST experiments show that both complexes are responsive to pH and temperature changes. Higher pH and temperature sensitivities are obtained with BIRDS for either complex when using the chemical shift difference between two proton resonances vs. using the chemical shift of a single proton resonance, thereby eliminating the need to use water resonance as reference. While CEST contrast for both agents is linearly dependent on pH within a relatively large range (i.e., 6.3-7.9), much stronger CEST contrast is obtained with YbDOTA-4AmP5− than with TmDOTA-4AmP5−. In addition, we demonstrate the prospect of using BIRDS to calibrate CEST as new platform for quantitative pH imaging. PMID:24801742

  8. Periodic behavior of lanthanide coordination within reverse micelles.

    PubMed

    Ellis, Ross J; Meridiano, Yannick; Chiarizia, Renato; Berthon, Laurence; Muller, Julie; Couston, Laurent; Antonio, Mark R

    2013-02-18

    Trends in lanthanide(III) (Ln(III)) coordination were investigated within nanoconfined solvation environments. Ln(III) ions were incorporated into the cores of reverse micelles (RMs) formed with malonamide amphiphiles in n-heptane by contact with aqueous phases containing nitrate and Ln(III); both insert into pre-organized RM units built up of DMDOHEMA (N,N'-dimethyl-N,N'-dioctylhexylethoxymalonamide) that are either relatively large and hydrated or small and dry, depending on whether the organic phase is acidic or neutral, respectively. Structural aspects of the Ln(III) complex formation and the RM morphology were obtained by use of XAS (X-ray absorption spectroscopy) and SAXS (small-angle X-ray scattering). The Ln(III) coordination environments were determined through use of L(3)-edge XANES (X-ray absorption near edge structure) and EXAFS (extended X-ray absorption fine structure), which provide metrical insights into the chemistry across the period. Hydration numbers for the Eu species were measured using TRLIFS (time-resolved laser-induced fluorescence spectroscopy). The picture that emerges from a system-wide perspective of the Ln-O interatomic distances and number of coordinating oxygen atoms for the extracted complexes of Ln(III) in the first half of the series (i.e., Nd, Eu) is that they are different from those in the second half of the series (i.e., Tb, Yb): the number of coordinating oxygen atoms decrease from 9O for early lanthanides to 8O for the late ones--a trend that is consistent with the effect of the lanthanide contraction. The environment within the RM, altered by either the presence or absence of acid, also had a pronounced influence on the nitrate coordination mode; for example, the larger, more hydrated, acidic RM core favors monodentate coordination, whereas the small, dry, neutral core favors bidentate coordination to Ln(III). These findings show that the coordination chemistry of lanthanides within nanoconfined environments is neither

  9. Lessons learned from dinuclear lanthanide nano-magnets.

    PubMed

    Habib, Fatemah; Murugesu, Muralee

    2013-04-21

    The quest for higher density information storage has led to the investigation of Single-Molecule Magnets (SMMs) as potential molecules to be applied in materials such as hard discs. In order for this to occur, one must first design metal complexes which can retain magnetic information at temperatures where these applications become possible. This can only be achieved through answering and understanding fundamental questions regarding the observed physical properties of SMMs. While mononuclear lanthanide complexes have shown promise in obtaining high energy barriers for the reversal of the magnetisation they are limited to Single-Ion Magnet behaviour intrinsic to one metal centre with a limited number of unpaired electrons. As a way of increasing the effective anisotropic barrier, systems with higher nuclearity have been sought to increase the spin ground state of the molecule. Dinuclear complexes are presented as key compounds in studying and understanding the nature of magnetic interactions between metal ions. This tutorial review will span a number of dinuclear 4f complexes which have been critical in our understanding of the way in which lanthanide centres in a complex interact magnetically. It will examine key bridging moieties from the more common oxygen-based groups to newly discovered radical-based bridges and draw conclusions regarding the most effective superexchange pathways allowing the most efficient intracomplex interactions. PMID:23334210

  10. The role of lanthanides in optical materials

    SciTech Connect

    Weber, M.J.

    1995-05-01

    A survey is presented of the use of the lanthanides as chemical components in transmitting optical materials and as activators in materials for luminescent, electro-optic, magneto-optic, and various photosensitive applications.

  11. Novel states of matter with ultracold magnetic lanthanides

    NASA Astrophysics Data System (ADS)

    Kotochigova, Svetlana

    2016-05-01

    Ultracold atomic physics is now poised to enter a new regime, where far-more complex atomic species can be cooled and studied. Magnetic lanthanide atoms with their large magnetic moment and large orbital momentum are extreme examples of such species. In fact, ultracold gases of magnetic lanthanides provide the opportunity to examine strongly correlated matter, creating a platform to explore exotic many-body phases such as quantum ferrofluids, quantum liquid crystals, and supersolids. Experimental advances in trapping and cooling magnetic Dy and Er atoms are paving the way towards these goals. Over the last few years we have developed a framework for understanding the complex anisotropic interactions between magnetic lanthanide atoms. Our theoretical model uses novel tools and advanced numerical treatments to describe the underlying mechanism that generates correlations and chaos in dipolar scattering and bridges the enormous conceptual gap between simple atoms and complex molecules. This allows us to explain the origin of the dense spectra and statistics of the observed Er and Dy collisional resonances due to the anisotropy of the short- and long-range interactions between the atoms. We also study the distribution of the values of the molecular wave functions to isolate Anderson-type localized states within chaotic structures and confirm the existence of an intermediate chaotic regime. In addition, our model for the three-body recombination via the formation of a resonant trimer has identified the origin of the temperature-sensitive resonance density observed in both Er and Dy collisions as due to d-wave entrance channel collisions. This work is supported by AFOSR (No. FA9550-14-1-0321) and NSF (No. PHY-1308573) grants.

  12. White-Light-Emitting Lanthanide Metallogels with Tunable Luminescence and Reversible Stimuli-Responsive Properties.

    PubMed

    Chen, Pangkuan; Li, Qiaochu; Grindy, Scott; Holten-Andersen, Niels

    2015-09-16

    We have developed model light-emitting metallogels functionalized with lanthanide metal-ligand coordination complexes via a terpyridyl-end-capped four-arm poly(ethylene glycol) polymer. The optical properties of these highly luminescent polymer networks are readily modulated over a wide spectrum, including white-light emission, simply by tuning of the lanthanide metal ion stoichiometry. Furthermore, the dynamic nature of the Ln-N coordination bonding leads to a broad variety of reversible stimuli-responsive properties (mechano-, vapo-, thermo-, and chemochromism) of both sol-gel systems and solid thin films. The versatile functional performance combined with the ease of assembly suggests that this lanthanide coordination polymer design approach offers a robust pathway for future engineering of multi-stimuli-responsive polymer materials. PMID:26301493

  13. LANTHANIDE ENHANCE LUMINESCENCE (LEL) WITH ONE AND TWO PHOTON EXCITATION OF QUANTUM DYES LANTHANIDE (III) - MACROCYCLES

    EPA Science Inventory

    Title: Lanthanide Enhance Luminescence (LEL) with one and two photon excitation of Quantum Dyes? Lanthanide(III)-Macrocycles
    Principal Author:
    Robert C. Leif, Newport Instruments
    Secondary Authors:
    Margie C. Becker, Phoenix Flow Systems
    Al Bromm, Virginia Commonw...

  14. Tetrametallic lanthanide(III) phosphonate cages: synthetic, structural and magnetic studies.

    PubMed

    Zangana, Karzan H; Pineda, Eufemio Moreno; Winpenny, Richard E P

    2014-12-01

    The synthesis, structures and magnetic properties of a family of lanthanide complexes containing phosphonate ligands are reported. Reaction of hydrated lanthanide nitrate and (t)butylphosphonic acid under reflux conditions in iso-butanol, in the presence of pivalic acid as a co-ligand produced five new lanthanide complexes; pyridine (py) was present as a base. The compounds formed are tetrametallic, with the general formula [pyH]4[Ln4(μ3-OH)(O3P(t)Bu)3(HO3P(t)Bu)(O2C(t)Bu)2(NO3)6] where Ln = Gd(III), 1; Tb(III), 2; Dy(III), 3; Ho(III), 4 and Er(III), 5. The metal sites within the complexes lie on the vertices of a triangle-based pyramid, with phosphonate ligands on the triangular faces linking the apical Ln site to the Ln sites in the base. Each lanthanide(III) site is eight-coordinate. Magnetic studies of the compounds show a decline in the product χ(M)T with T; modelling the behaviour of 1 shows anti-ferromagnetic exchange between Gd(III) centres within the triangle with a negligible interaction to the fourth Gd(III) centre at the apex of the trigonal pyramid. PMID:25310820

  15. Lanthanide Oleates: Chelation, Self-assembly, and Exemplification of Ordered Nanostructured Colloidal Contrast Agents for Medical Imaging

    SciTech Connect

    Liu, Guozhen; Conn, Charlotte E.; Drummond, Calum J.

    2010-01-12

    Eight lanthanide(III) oleates have been prepared and characterized. The chelation and self-assembly structures of these rare-earth oleates have been studied by elemental analysis, Fourier transfer infrared spectroscopy (FTIR), and X-ray powder diffraction (XRD) analysis. Elemental analysis and FTIR results indicate that three oleate anions are complexed with one lanthanide cation and, with the exception of anhydrous cerium(III) oleate, form either a mono- or a hemihydrate. The X-ray analysis showed that the neat lanthanide soaps have a lamellar bilayer structure at room temperature. The thermal behavior has been investigated by cross-polarized optical microscopy (POM), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). POM scans showed that all the lanthanide oleates form a lamellar phase in the presence of excess water. Small-angle X-ray scattering (SAXS) and XRD were used to investigate the internal structure of the bulk lanthanide oleates in excess water, and these X-ray results confirmed that the lanthanide oleates do not swell in water. Select lanthanide oleates were dispersed in water to form nonswelling lamellar submicrometer particles, confirmed by dynamic light scattering (DLS) and synchrotron SAXS measurements. NMR results indicated that colloidal dispersions of lanthanide oleates containing paramagnetic ions, such as gadolinium(III), terbium(III), and dysprosium(III), have a significant effect on the longitudinal (T{sub 1}) and transverse (T{sub 2}) relaxation times of protons in water. Time-resolved fluorescence measurements have demonstrated that colloidal dispersions of europium(III) oleate exhibit strong luminescence. The rare earth metal soaps exemplify the potential of self-assembled chelating amphiphiles as contrast agents in medical imaging modalities such as magnetic resonance imaging (MRI) and fluorescence imaging.

  16. From antenna to assay: lessons learned in lanthanide luminescence.

    PubMed

    Moore, Evan G; Samuel, Amanda P S; Raymond, Kenneth N

    2009-04-21

    Ligand-sensitized, luminescent lanthanide(III) complexes are of considerable importance because their unique photophysical properties (microsecond to millisecond lifetimes, characteristic and narrow emission bands, and large Stokes shifts) make them well suited as labels in fluorescence-based bioassays. The long-lived emission of lanthanide(III) cations can be temporally resolved from scattered light and background fluorescence to vastly enhance measurement sensitivity. One challenge in this field is the design of sensitizing ligands that provide highly emissive complexes with sufficient stability and aqueous solubility for practical applications. In this Account, we give an overview of some of the general properties of the trivalent lanthanides and follow with a summary of advances made in our laboratory in the development of highly luminescent Tb(III) and Eu(III) complexes for applications in biotechnology. A focus of our research has been the optimization of these compounds as potential commercial agents for use in homogeneous time-resolved fluorescence (HTRF) technology. Our approach involves developing high-stability octadentate Tb(III) and Eu(III) complexes that rely on all-oxygen donor atoms and using multichromophore chelates to increase molar absorptivity; earlier examples utilized a single pendant chromophore (that is, a single "antenna"). Ligands based on 2-hydroxyisophthalamide (IAM) provide exceptionally emissive Tb(III) complexes with quantum yield values up to approximately 60% that are stable at the nanomolar concentrations required for commercial assays. Through synthetic modification of the IAM chromophore and time-dependent density functional theory (TD-DFT) calculations, we have developed a method to predict absorption and emission properties of these chromophores as a tool to guide ligand design. Additionally, we have investigated chiral IAM ligands that yield Tb(III) complexes possessing both high quantum yield values and strong circularly

  17. In vitro selection of a new lanthanide-dependent DNAzyme for ratiometric sensing lanthanides.

    PubMed

    Huang, Po-Jung Jimmy; Vazin, Mahsa; Liu, Juewen

    2014-10-01

    Developing biosensors for lanthanides is an important but challenging analytical task. To address this problem, in vitro selection of RNA-cleaving DNAzymes was carried out using a library containing a region of 35 random nucleotides in the presence of Lu(3+), since Lu(3+) was reported to be the most efficient lanthanide for RNA cleavage. The resulting DNA sequences can be aligned to a single family with two conserved stretches of nucleotides. One of the representative DNAzymes (named Lu12) was further studied. Lu12 is more active with smaller lanthanides and has the lowest activity in the presence of the largest lanthanide (lutetium). Its cleavage rate is 0.12 min(-1) in the presence of 10 μM Nd(3+) at pH 6.0. This is a new DNAzyme, and a catalytic beacon sensor is designed by attaching a fluorophore/quencher pair, detecting Nd(3+) down to 0.4 nM (72 parts-per-trillion). This DNAzyme is highly selective for lanthanides as well, showing cleavage only with two nonlanthanide ions: Y(3+) and Pb(2+). We previously reported a DNAzyme named Ce13d, which has similar responses to all the trivalent lanthanides. Combining these two allows for a ratiometric assay that identifies a few large lanthanides.

  18. Stabilization of molecular lanthanide polysulfides by bulky scorpionate ligands.

    PubMed

    Kühling, Marcel; McDonald, Robert; Liebing, Phil; Hilfert, Liane; Ferguson, Michael J; Takats, Josef; Edelmann, Frank T

    2016-07-01

    Well-defined lanthanide polysulfide complexes containing S4(2-) and S5(2-) ligands, the samarium(iii) pentasulfide complex Sm(Tp(iPr2))(κ(1)-3,5-(i)Pr2Hpz)(S5) and the tetrasulfide-bridged binuclear ytterbium(iii) complex (μ-S4)[Yb(Tp(iPr2))(κ(1)-3,5-(i)Pr2Hpz)(κ(2)-3,5-(i)Pr2pz)]2 (Tp(iPr2) = hydro-tris(3,5-diisopropylpyrazolyl)borate), have been synthesized and structurally characterized by single-crystal X-ray diffraction. PMID:27151931

  19. Electronic Structure of Small Lanthanide Containing Molecules

    NASA Astrophysics Data System (ADS)

    Kafader, Jared O.; Ray, Manisha; Topolski, Josey E.; Chick Jarrold, Caroline

    2016-06-01

    Lanthanide-based materials have unusual electronic properties because of the high number of electronic degrees of freedom arising from partial occupation of 4f orbitals, which make these materials optimal for their utilization in many applications including electronics and catalysis. Electronic spectroscopy of small lanthanide molecules helps us understand the role of these 4f electrons, which are generally considered core-like because of orbital contraction, but are energetically similar to valence electrons. The spectroscopy of small lanthanide-containing molecules is relatively unexplored and to broaden this understanding we have completed the characterization of small cerium, praseodymium, and europium molecules using photoelectron spectroscopy coupled with DFT calculations. The characterization of PrO, EuH, EuO/EuOH, and CexOy molecules have allowed for the determination of their electron affinity, the assignment of numerous anion to neutral state transitions, modeling of anion/neutral structures and electron orbital occupation.

  20. Separations of actinides, lanthanides and other metals

    DOEpatents

    Smith, Barbara F.; Jarvinen, Gordon D.; Ensor, Dale D.

    1995-01-01

    An organic extracting solution comprised of a bis(acylpyrazolone or a substituted bis(acylpyrazolone) and an extraction method useful for separating certain elements of the actinide series of the periodic table having a valence of four from one other, and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also from one or more of the substances in a group consisting of hexavalent actinides, trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals and also useful for separating hexavalent actinides from one or more of the substances in a group consisting of trivalent actinides, trivalent lanthanides, trivalent iron, trivalent aluminum, divalent metals, and monovalent metals.

  1. Spectrophotometric, potentiometric, and gravimetric determination of lanthanides with peri-dihydroxynaphthindenone

    SciTech Connect

    Hassan, S.S.M.; Mahmoud, W.H.

    1982-02-01

    Sensitive and reasonably selective methods are described for the spectrophotometric, potentiometric, and gravimetric determination of lanthanides using peri-dihydroxynaphthindenone as a novel chromogenic and precipitating reagent. The reagent forms a stable 1:2 (metal:reagent) type of complex with light lanthanides at pH 2-7 in 1:1 ethanol-water mixture. Low metal concentrations (<10 ..mu..g/mL) develop colored species (lambda/sub max/ 580 to 590 nm, epsilon/sub max/ (4-6) x 10/sup 4/ L mol/sup -1/ cm/sup -1/) which obey Beer's law. Quantitative precipitation of the complexes from metal solutions of concentrations > 100 ..mu..g/mL permits both gravimetric quantitation by igniting the precipitates to the metal oxides and potentiometric titration of the excess reagent. Results with an average recovery of 98% (standard deviation 0.7%) are obtainable for 0.1 ..mu..g to 200 mg of all light lanthanides. Many foreign ions naturally occurring or frequently associated with lanthanides do not interfere or can be tolerated.

  2. Actinide Lanthanide Separation Process – ALSEP

    SciTech Connect

    Gelis, Artem V.; Lumetta, Gregg J.

    2014-01-29

    Separation of the minor actinides (Am, Cm) from the lanthanides at an industrial scale remains a significant technical challenge for closing the nuclear fuel cycle. To increase the safety of used nuclear fuel (UNF) reprocessing, as well as reduce associated costs, a novel solvent extraction process has been developed. The process allows for partitioning minor actinides, lanthanides and fission products following uranium/plutonium/neptunium removal; minimizing the number of separation steps, flowsheets, chemical consumption, and waste. This new process, Actinide Lanthanide SEParation (ALSEP), uses an organic solvent consisting of a neutral diglycolamide extractant, either N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) or N,N,N',N'-tetraoctyldiglycolamide (TODGA), and an acidic extractant 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]), dissolved in an aliphatic diluent (e.g. n-dodecane). The An/Ln co-extraction is conducted from moderate-to-strong nitric acid, while the selective stripping of the minor actinides from the lanthanides is carried out using a polyaminocarboxylic acid/citrate buffered solution at pH anywhere between 3 and 4.5. The extraction and separation of the actinides from the fission products is very effective in a wide range of HNO3 concentrations and the minimum separation factors for lanthanide/Am exceed 30 for Nd/Am, reaching > 60 for Eu/Am under some conditions. The experimental results presented here demonstrate the great potential for a combined system, consisting of a neutral extractant such as T2EHDGA or TODGA, and an acidic extractant such as HEH[EHP], for separating the minor actinides from the lanthanides.

  3. Lanthanide-based laser-induced phosphorescence for spray diagnostics

    NASA Astrophysics Data System (ADS)

    van der Voort, D. D.; Maes, N. C. J.; Lamberts, T.; Sweep, A. M.; van de Water, W.; Kunnen, R. P. J.; Clercx, H. J. H.; van Heijst, G. J. F.; Dam, N. J.

    2016-03-01

    Laser-induced phosphorescence (LIP) is a relatively recent and versatile development for studying flow dynamics. This work investigates certain lanthanide-based molecular complexes for their use in LIP for high-speed sprays. Lanthanide complexes in solutions have been shown to possess long phosphorescence lifetimes (˜1-2 ms) and to emit light in the visible wavelength range. In particular, europium and terbium complexes are investigated using fluorescence/phosphorescence spectrometry, showing that europium-thenoyltrifluoracetone-trioctylphosphineoxide (Eu-TTA-TOPO) can be easily and efficiently excited using a standard frequency-tripled Nd:YAG laser. The emitted spectrum, with maximum intensity at a wavelength of 614 nm, is shown not to vary strongly with temperature (293-383 K). The decay constant of the phosphorescence, while independent of ambient pressure, decreases by approximately 12 μs/K between 323 and 373 K, with the base level of the decay constant dependent on the used solvent. The complex does not luminesce in the gas or solid state, meaning only the liquid phase is visualized, even in an evaporating spray. By using an internally excited spray containing the phosphorescent complex, the effect of vaporization is shown through the decrease in measured intensity over the length of the spray, together with droplet size measurements using interferometric particle imaging. This study shows that LIP, using the Eu-TTA-TOPO complex, can be used with different solvents, including diesel surrogates. Furthermore, it can be easily handled and used in sprays to investigate spray breakup and evaporation.

  4. Lanthanide-based laser-induced phosphorescence for spray diagnostics.

    PubMed

    van der Voort, D D; Maes, N C J; Lamberts, T; Sweep, A M; van de Water, W; Kunnen, R P J; Clercx, H J H; van Heijst, G J F; Dam, N J

    2016-03-01

    Laser-induced phosphorescence (LIP) is a relatively recent and versatile development for studying flow dynamics. This work investigates certain lanthanide-based molecular complexes for their use in LIP for high-speed sprays. Lanthanide complexes in solutions have been shown to possess long phosphorescence lifetimes (∼1-2 ms) and to emit light in the visible wavelength range. In particular, europium and terbium complexes are investigated using fluorescence/phosphorescence spectrometry, showing that europium-thenoyltrifluoracetone-trioctylphosphineoxide (Eu-TTA-TOPO) can be easily and efficiently excited using a standard frequency-tripled Nd:YAG laser. The emitted spectrum, with maximum intensity at a wavelength of 614 nm, is shown not to vary strongly with temperature (293-383 K). The decay constant of the phosphorescence, while independent of ambient pressure, decreases by approximately 12 μs/K between 323 and 373 K, with the base level of the decay constant dependent on the used solvent. The complex does not luminesce in the gas or solid state, meaning only the liquid phase is visualized, even in an evaporating spray. By using an internally excited spray containing the phosphorescent complex, the effect of vaporization is shown through the decrease in measured intensity over the length of the spray, together with droplet size measurements using interferometric particle imaging. This study shows that LIP, using the Eu-TTA-TOPO complex, can be used with different solvents, including diesel surrogates. Furthermore, it can be easily handled and used in sprays to investigate spray breakup and evaporation. PMID:27036779

  5. Shear viscosity coefficient of liquid lanthanides

    SciTech Connect

    Patel, H. P. Thakor, P. B. Prajapati, A. V.; Sonvane, Y. A.

    2015-05-15

    Present paper deals with the computation of shear viscosity coefficient (η) of liquid lanthanides. The effective pair potential v(r) is calculated through our newly constructed model potential. The Pair distribution function g(r) is calculated from PYHS reference system. To see the influence of local field correction function, Hartree (H), Tailor (T) and Sarkar et al (S) local field correction function are used. Present results are compared with available experimental as well as theoretical data. Lastly, we found that our newly constructed model potential successfully explains the shear viscosity coefficient (η) of liquid lanthanides.

  6. Lanthanides in silicate glasses: A vibrational spectroscopic study

    NASA Astrophysics Data System (ADS)

    Ellison, Adam J. G.; Hess, Paul C.

    1990-09-01

    Parallel- and perpendicular-polarized Raman and KBr pellet transmission IR spectra of quenched 10K2O-50SiO2-nR2O3 (R = La, Gd, Yb; n = 0, 1, 5, 10 mol) glasses are presented. Increasing lanthanide oxide concentration produces partially-polarized high-frequency bands at 1030, 940, and 860 cm-1, assigned to the symmetric stretching modes of SiO4 tetrahedra containing 1, 2, and 4 nonbridging oxygen, respectively, in which the nonbridging oxygen coordinate primarily with lanthanides. Lanthanides therefore form silicate anions that are depolymerized relative to the bulk liquid and which have no counterparts in R2O3-SiO2 binary systems. The spectra indicate that there is little sharing of nonbridging oxygen by K and lanthanides. The spectra of glasses containing different lanthanides at the same concentration are qualitatively and quantitatively very similar. Lanthanides have energetically unfavorable interactions with the network structure of polymerized liquids compared to cations of lower valence. If lanthanides coordinate nonbridging oxygen without the aid of K, then lanthanide saturation concentrations will show modest increases with increasing (Na,K)/Al in peralkaline liquids, except in liquids in which P2O5 concentration is comparable to the total lanthanide concentration. Since differences in lanthanide ionic radii have small effects upon the spectra, lanthanide solution mechanisms in silicate glasses (and by inference silicate liquids) are probably very similar.

  7. Lanthanide-IMAC enrichment of carbohydrates and polyols.

    PubMed

    Schemeth, Dieter; Rainer, Matthias; Messner, Christoph B; Rode, Bernd M; Bonn, Günther K

    2014-03-01

    In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4-butandiole dimethacrylate using azo-bis-isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by applying high pH values. The new method was evaluated by single standard solutions, mixtures of standards, honey and a more complex extract of Cynara scolymus. The washing step was accomplished by acetonitrile in excess volumes. Elution of enriched carbohydrates was successfully performed with deionized water. The subsequent analysis was carried out with matrix-free laser desorption/ionization-time of flight mass spectrometry involving a TiO2 -coated steel target, especially suitable for the measurement of low-molecular-weight substances. Quantitative analysis of the sugar alcohol xylitol as well as the determination of the maximal loading capacity was performed by gas chromatography in conjunction with mass spectrometric detection after chemical derivatization. In a parallel approach quantum mechanical geometry optimizations were performed in order to compare the coordination behavior of various trivalent lanthanide ions. PMID:24097333

  8. Lanthanide-IMAC enrichment of carbohydrates and polyols.

    PubMed

    Schemeth, Dieter; Rainer, Matthias; Messner, Christoph B; Rode, Bernd M; Bonn, Günther K

    2014-03-01

    In this study a new type of immobilized metal ion affinity chromatography resin for the enrichment of carbohydrates and polyols was synthesized by radical polymerization reaction of vinyl phosphonic acid and 1,4-butandiole dimethacrylate using azo-bis-isobutyronitrile as radical initiator. Interaction between the chelated trivalent lanthanide ions and negatively charged hydroxyl groups of carbohydrates and polyols was observed by applying high pH values. The new method was evaluated by single standard solutions, mixtures of standards, honey and a more complex extract of Cynara scolymus. The washing step was accomplished by acetonitrile in excess volumes. Elution of enriched carbohydrates was successfully performed with deionized water. The subsequent analysis was carried out with matrix-free laser desorption/ionization-time of flight mass spectrometry involving a TiO2 -coated steel target, especially suitable for the measurement of low-molecular-weight substances. Quantitative analysis of the sugar alcohol xylitol as well as the determination of the maximal loading capacity was performed by gas chromatography in conjunction with mass spectrometric detection after chemical derivatization. In a parallel approach quantum mechanical geometry optimizations were performed in order to compare the coordination behavior of various trivalent lanthanide ions.

  9. Molecular lanthanide single-ion magnets: from bulk to submonolayers.

    PubMed

    Dreiser, J

    2015-05-13

    Single-ion magnets (SIMs) are mononuclear molecular complexes exhibiting slow relaxation of magnetization. They are currently attracting a lot of interest because of potential applications in spintronics and quantum information processing. However, exploiting SIMs in, e.g. molecule-inorganic hybrid devices requires a fundamental understanding of the effects of molecule-substrate interactions on the SIM magnetic properties. In this review the properties of lanthanide SIMs in the bulk crystalline phase and deposited on surfaces in the (sub)monolayer regime are discussed. As a starting point trivalent lanthanide ions in a ligand field will be described, and the challenges in characterizing the ligand field are illustrated with a focus on several spectroscopic techniques which are able to give direct information on the ligand-field split energy levels. Moreover, the dominant mechanisms of magnetization relaxation in the bulk phase are discussed followed by an overview of SIMs relevant for surface deposition. Further, a short introduction will be given on x-ray absorption spectroscopy, x-ray magnetic circular dichroism and scanning tunneling microscopy. Finally, the recent experiments on surface-deposited SIMs will be reviewed, along with a discussion of future perspectives.

  10. Lanthanide Phytanates: Liquid-Crystalline Phase Behavior, Colloidal Particle Dispersions, and Potential as Medical Imaging Agents

    SciTech Connect

    Conn, Charlotte E.; Panchagnula, Venkateswarlu; Weerawardena, Asoka; Waddington, Lynne J.; Kennedy, Danielle F.; Drummond, Calum J.

    2010-08-23

    Lanthanide salts of phytanic acid, an isoprenoid-type amphiphile, have been synthesized and characterized. Elemental analysis and FTIR spectroscopy were used to confirm the formed product and showed that three phytanate anions are complexed with one lanthanide cation. The physicochemical properties of the lanthanide phytanates were investigated using DSC, XRD, SAXS, and cross-polarized optical microscopy. Several of the hydrated salts form a liquid-crystalline hexagonal columnar mesophase at room temperature, and samarium(III) phytanate forms this phase even in the absence of water. Select lanthanide phytanates were dispersed in water, and cryo-TEM images indicate that some structure has been retained in the dispersed phase. NMR relaxivity measurements were conducted on these systems. It has been shown that a particulate dispersion of gadolinium(III) phytanate displays proton relaxivity values comparable to those of a commercial contrast agent for magnetic resonance imaging and a colloidal dispersion of europium(III) phytanate exhibits the characteristics of a fluorescence imaging agent.

  11. Thermodynamic parameters governing the self-assembly of head-head-head lanthanide bimetallic helicates.

    PubMed

    Jensen, Thomas B; Scopelliti, Rosario; Bünzli, Jean-Claude G

    2007-01-01

    The heterobitopic ligands L ABX (X=1, 2, 3, 4 or 5), differing only by a Cl or NEt(2) substituent, have been designed to complex with a pair of lanthanide ions to form triple-stranded bimetallic helicates of overall composition [Ln2(L ABX)3]6+. The percentage of HHH (head-head-head) isomer, in which each of the three ligand strands coordinates to the same lanthanide ion with the same coordination unit, is deciding the ability of the ligands to selectively form heterobimetallic complexes containing one luminescent and one magnetic or two different luminescent ions. It deviates significantly from the statistical value of 25 % and ranges from 6-20 % for L AB2 complexes to 93-96 % for L AB4 complexes. The equilibrium between HHT (head-head-tail) and HHH isomers has been investigated in detail for homobimetallic helicates (Ln=Y, La, Ce, Pr, Nd, Sm, Eu, Lu) by means of variable temperature NMR and thermodynamic parameters have been determined. The equilibrium is characterized by small values of DeltaH and DeltaS, which vary in opposite direction along the lanthanide series for complexes with the same ligand in a way that keeps the value of DeltaG almost constant. The results are interpreted in terms of differences in interstrand stacking, ion-dipole interactions and metal-metal repulsion. PMID:17600785

  12. Four unexpected lanthanide coordination polymers involving in situ reaction of solvent N, N-Dimethylformamide

    SciTech Connect

    Jin, Jun-Cheng; Tong, Wen-Quan; Fu, Ai-Yun; Xie, Cheng-Gen; Chang, Wen-Gui; Wu, Ju; Xu, Guang-Nian; Zhang, Ya-Nan; Li, Jun; Li, Yong; Yang, Peng-Qi

    2015-05-15

    Four unexpected 2D lanthanide coordination polymers have been synthesized through in situ reactions of DMF solvent under solvothermal conditions. The isostructural complexes 1–3 contain four types of 2{sub 1} helical chains. While the Nd(III) ions are bridged through μ{sub 2}-HIDC{sup 2−} and oxalate to form a 2D sheet along the bc plane without helical character in 4. Therefore, complex 1 exhibits bright red solid-state phosphorescence upon exposure to UV radiation at room temperature. - Graphical abstract: Four unexpected 2D lanthanide coordination polymers have been synthesized through in situ reactions of solvent DMF to formate acid or oxalic acid under solvothermal conditions. The isostructural complexes 1–3 contain four types of different 2{sub 1} helical chains in the 2D layer and 1 exhibits bright red solid-state phosphorescence upon UV radiation. - Highlights: • Four unexpected 2D lanthanide coordination compounds have been synthesized through in situ reactions under solvothermal conditions. • The complexes 1–3 contain four types of 2{sub 1} helical chains in the layer. • Complex 1 exhibits bright red solid-state phosphorescence upon exposure to UV radiation at room temperature.

  13. Structure of the two-subsite beta-D-xylosidase from Selenomonas ruminantium in complex with 1,3-bis[tris(hydroxymethyl)methylamino]propane

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The three-dimensional structure of the catalytically-efficient beta-xylosidase from Selenomonas ruminantium in complex with competitive inhibitor 1,3 bis[tris(hydroxymethyl)methylamino]propane (BTP) was determined by using X-ray crystallography (1.3 Å resolution). Most H bonds between inhibitor and...

  14. The Effects of Trivalent Lanthanide Cationization on the Electron Transfer Dissociation of Acidic Fibrinopeptide B and its Analogs

    NASA Astrophysics Data System (ADS)

    Commodore, Juliette J.; Cassady, Carolyn J.

    2016-09-01

    Electrospray ionization (ESI) on mixtures of acidic fibrinopeptide B and two peptide analogs with trivalent lanthanide salts generates [M + Met + H]4+, [M + Met]3+, and [M + Met -H]2+, where M = peptide and Met = metal (except radioactive promethium). These ions undergo extensive and highly efficient electron transfer dissociation (ETD) to form metallated and non-metallated c- and z-ions. All metal adducted product ions contain at least two acidic sites, which suggest attachment of the lanthanide cation at the side chains of one or more acidic residues. The three peptides undergo similar fragmentation. ETD on [M + Met + H]4+ leads to cleavage at every residue; the presence of both a metal ion and an extra proton is very effective in promoting sequence-informative fragmentation. Backbone dissociation of [M + Met]3+ is also extensive, although cleavage does not always occur between adjacent glutamic acid residues. For [M + Met - H ]2+, a more limited range of product ions form. All lanthanide metal peptide complexes display similar fragmentation except for europium (Eu). ETD on [M + Eu - H]2+ and [M + Eu]3+ yields a limited amount of peptide backbone cleavage; however, [M + Eu + H]4+ dissociates extensively with cleavage at every residue. With the exception of the results for Eu(III), metallated peptide ion formation by ESI, ETD fragmentation efficiencies, and product ion formation are unaffected by the identity of the lanthanide cation. Adduction with trivalent lanthanide metal ions is a promising tool for sequence analysis of acidic peptides by ETD.

  15. The Effects of Trivalent Lanthanide Cationization on the Electron Transfer Dissociation of Acidic Fibrinopeptide B and its Analogs.

    PubMed

    Commodore, Juliette J; Cassady, Carolyn J

    2016-09-01

    Electrospray ionization (ESI) on mixtures of acidic fibrinopeptide B and two peptide analogs with trivalent lanthanide salts generates [M + Met + H](4+), [M + Met](3+), and [M + Met -H](2+), where M = peptide and Met = metal (except radioactive promethium). These ions undergo extensive and highly efficient electron transfer dissociation (ETD) to form metallated and non-metallated c- and z-ions. All metal adducted product ions contain at least two acidic sites, which suggest attachment of the lanthanide cation at the side chains of one or more acidic residues. The three peptides undergo similar fragmentation. ETD on [M + Met + H](4+) leads to cleavage at every residue; the presence of both a metal ion and an extra proton is very effective in promoting sequence-informative fragmentation. Backbone dissociation of [M + Met](3+) is also extensive, although cleavage does not always occur between adjacent glutamic acid residues. For [M + Met - H ](2+), a more limited range of product ions form. All lanthanide metal peptide complexes display similar fragmentation except for europium (Eu). ETD on [M + Eu - H](2+) and [M + Eu](3+) yields a limited amount of peptide backbone cleavage; however, [M + Eu + H](4+) dissociates extensively with cleavage at every residue. With the exception of the results for Eu(III), metallated peptide ion formation by ESI, ETD fragmentation efficiencies, and product ion formation are unaffected by the identity of the lanthanide cation. Adduction with trivalent lanthanide metal ions is a promising tool for sequence analysis of acidic peptides by ETD. Graphical Abstract ᅟ.

  16. The solution structure of Ln (DOTP) 5- complexxes. A comparison of lanthanide-induced paramagnetic shifts with the MMX energy-minimized structure

    NASA Astrophysics Data System (ADS)

    Geraldes, Carlos F. G. C.; Sherry, A. Dean; Kiefer, Garry E.

    Complexes between the trivalent lanthanide ions and the macrocyclic chelate 1,4,7,10-tetraazacyclododecane- N,N',N″,N‴-tetra(methylene phosphonate) (DOTP) have been examined by high-resolution NMR spectroscopy. The proton spectra of the diamagnetic La(DOTP) 5- and Lu(DOTP) 5- complexes provide evidence for very rigid chelate structures with the ethylenediamine-containing chelate rings essentially locked into a single conformation at room temperature. The activation energy for ethylenediamine chelate ring interconversions in these complexes is approximately 100 kJ mol -1, considerably higher than that reported previously for the corresponding Ln(DOTA) - complexes (DOTA is the tetraacetate analog of DOTP). Lanthanide-induced shifts are reported for all 1H, 13C, and 31P nuclei in 11 Ln(DOTP) 5- complexes. The proton spectra of these complexes display unusually large lanthanide-induced shifts, one showing a spectrum in which the 1H resonances span 900 ppm. The contact and pseudocontact contributions to these shifts were separated using Reilley's temperature-independent method and the resulting pseudocontact lanthanide-induced NMR shifts were in excellent agreement with those calculated for a structure derived using MMX molecular modeling methods. The pseudocontact shifts provide evidence for Ln (DOTP) 5- chelates which have virtually identical structures along the lanthanide series, with the possible exception of Tm(DOTP) 5-.

  17. Lanthanide-Catalyzed Reversible Alkynyl Exchange by Carbon-Carbon Single-Bond Cleavage Assisted by a Secondary Amino Group.

    PubMed

    Shao, Yinlin; Zhang, Fangjun; Zhang, Jie; Zhou, Xigeng

    2016-09-12

    Lanthanide-catalyzed alkynyl exchange through C-C single-bond cleavage assisted by a secondary amino group is reported. A lanthanide amido complex is proposed as a key intermediate, which undergoes unprecedented reversible β-alkynyl elimination followed by alkynyl exchange and imine reinsertion. The in situ homo- and cross-dimerization of the liberated alkyne can serve as an additional driving force to shift the metathesis equilibrium to completion. This reaction is formally complementary to conventional alkyne metathesis and allows the selective transformation of internal propargylamines into those bearing different substituents on the alkyne terminus in moderate to excellent yields under operationally simple reaction conditions. PMID:27510403

  18. Lanthanide doped strontium-barium cesium halide scintillators

    SciTech Connect

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  19. Acidic 1,3-propanediaminetetraacetato lanthanides with luminescent and catalytic ester hydrolysis properties

    SciTech Connect

    Chen, Mao-Long; Shi, Yan-Ru; Yang, Yu-Chen; Zhou, Zhao-Hui

    2014-11-15

    In acidic solution, a serials of water-soluble coordination polymers (CPs) were isolated as zonal 1D-CPs 1,3-propanediaminetetraacetato lanthanides [Ln(1,3-H{sub 3}pdta)(H{sub 2}O){sub 5}]{sub n}·2Cl{sub n}·3nH{sub 2}O [Ln=La, 1; Ce, 2; Pr, 3; Nd, 4; Sm, 5] (1,3-H{sub 4}pdta=1,3-propanediaminetetraacetic acid, C{sub 11}H{sub 18}N{sub 2}O{sub 8}) in high yields. When 1 eq. mol potassium hydroxide was added to the solutions of 1D-CPs, respectively, two 1D-CPs [Ln(1,3-H{sub 2}pdta)(H{sub 2}O){sub 3}]{sub n}·Cl{sub n}·2nH{sub 2}O [Ln=Sm, 6; Gd, 7] were isolated at room temperature and seven 2D-CPs [Ln(1,3-H{sub 2}pdta)(H{sub 2}O){sub 2}]{sub n}·Cl{sub n}·2nH{sub 2}O [Ln=La, 8; Ce, 9; Pr, 10; Nd, 11; Sm, 12; Eu, 13; Gd, 14] were isolated at 70 °C. When the crystals of 1–4 were hydrothermally heated at 180 °C with 1–2 eq. mol potassium hydroxide, four 3D-CPs [Ln(1,3-Hpdta)]{sub n}·nH{sub 2}O [Ln=La, 15; Ce, 16; Pr, 17; Nd, 18] were obtained. The two 2D-CPs [Ln(1,3-Hpdta)(H{sub 2}O)]{sub n}·4nH{sub 2}O (Sm, 19; Eu, 20) were isolated in similar reaction conditions. With the increments of pH value in the solution and reaction temperature, the structure becomes more complicated. 1–5 are soluble in water and 1 was traced by solution {sup 13}C({sup 1}H) NMR technique, the water-soluble lanthanides 1 and 5 show catalytic activity to ester hydrolysis reaction respectively, which indicate their important roles in the hydrolytic reaction. The europium complexes 13 and 20 show visible fluorescence at an excitation of 394 nm. The structure diversity is mainly caused by the variation of coordinated ligand in different pH values and lanthanide contraction effect. Acidic conditions are favorable for the isolations of lanthanide complexes in different structures and this may helpful to separate different lanthanides. The thermal stability investigations reveal that acidic condition is favorable to obtain the oxides at a lower temperature. - Graphical abstract: A series

  20. The Actinide-Lanthanide Separation Process

    SciTech Connect

    Lumetta, Gregg J.; Gelis, Artem V.; Carter, Jennifer C.; Niver, Cynthia M.; Smoot, Margaret R.

    2014-02-21

    The Actinide-Lanthanide SEParation (ALSEP) process is described. The process uses an extractant phase consisting of either N,N,N',N'-tetraoctyldiglycolamide (TODGA) or N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) combined with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]). The neutral TODGA or T2EHDGA serves to co-extract the trivalent actinide and lanthanide ions from nitric acid media. Switching the aqueous phase chemistry to a citrate buffered diethylenetriaminepentaacetic acid (DTPA) solution at pH 2.5 to 4 results in selective transfer of the actinides to the aqueous phase, thus resulting in separation of these two groups of elements.

  1. Relaxation-based distance measurements between a nitroxide and a lanthanide spin label

    NASA Astrophysics Data System (ADS)

    Jäger, H.; Koch, A.; Maus, V.; Spiess, H. W.; Jeschke, G.

    2008-10-01

    Distance measurements by electron paramagnetic resonance techniques between labels attached to biomacromolecules provide structural information on systems that cannot be crystallized or are too large to be characterized by NMR methods. However, existing techniques are limited in their distance range and sensitivity. It is anticipated by theoretical considerations that these limits could be extended by measuring the enhancement of longitudinal relaxation of a nitroxide label due to a lanthanide complex label at cryogenic temperatures. The relaxivity of the dysprosium complex with the macrocyclic ligand DOTA can be determined without direct measurements of longitudinal relaxation rates of the lanthanide and without recourse to model compounds with well defined distance by analyzing the dependence of relaxation enhancement on either temperature or concentration in homogeneous glassy frozen solutions. Relaxivities determined by the two calibration techniques are in satisfying agreement with each other. Error sources for both techniques are examined. A distance of about 2.7 nm is measured in a model compound of the type nitroxide-spacer-lanthanide complex and is found in good agreement with the distance in a modeled structure. Theoretical considerations suggest that an increase of the upper distance limit requires measurements at lower fields and temperatures.

  2. Nanometrization of Lanthanide-Based Coordination Polymers.

    PubMed

    Neaime, Chrystelle; Daiguebonne, Carole; Calvez, Guillaume; Freslon, Stéphane; Bernot, Kevin; Grasset, Fabien; Cordier, Stéphane; Guillou, Olivier

    2015-11-23

    Heteronuclear lanthanide-based coordination polymers are microcrystalline powders, the luminescence properties of which can be precisely tuned by judicious choice of the rare-earth ions. In this study, we demonstrate that such materials can also be obtained as stable solutions of nanoparticles in non-toxic polyols. Bulk powders of the formula [Ln2-2x Ln'2x (bdc)3 ⋅4 H2 O]∞ (where H2 bdc denotes 1,4-benzene-dicarboxylic acid, 0≤x≤1, and Ln and Ln' denote lanthanide ions of the series La to Tm plus Y) afford nanoparticles that have been characterized by dynamic light-scattering (DLS) and transmission electron microscopy (TEM) measurements. Their luminescence properties are similar to those of the bulk materials. Stabilities versus time and versus dilution with another solvent have been studied. This study has revealed that it is possible to tune the size of the nanoparticles. This process offers a reliable means of synthesizing suspensions of nanoparticles with tunable luminescence properties and tunable size distributions in a green solvent (glycerol). The process is also extendable to other coordination polymers and other solvents (ethylene glycol, for example). It constitutes a new route for the facile solubilization of lanthanide-based coordination polymers. PMID:26471940

  3. Switchable sensitizers stepwise lighting up lanthanide emissions

    PubMed Central

    Zhang, Yan; Jiao, Peng-Chong; Xu, Hai-Bing; Tang, Ming-Jing; Yang, Xiao-Ping; Huang, Shaoming; Deng, Jian-Guo

    2015-01-01

    Analagous to a long-ranged rocket equipped with multi-stage engines, a luminescent compound with consistent emission signals across a large range of concentrations from two stages of sensitizers can be designed. In this approach, ACQ, aggregation-caused quenching effect of sensitizers, would stimulate lanthanide emission below 10−4 M, and then at concentrations higher than 10−3 M, the “aggregation-induced emission” (AIE) effect of luminophores would be activated with the next set of sensitizers for lanthanide emission. Simultaneously, the concentration of the molecules could be monitored digitally by the maximal excitation wavelengths, due to the good linear relationship between the maximal excitation wavelengths and the concentrations {lg(M)}. This model, wherein molecules are assembled with two stages (both AIE and ACQ effect) of sensitizers, may provide a practicable strategy for design and construction of smart lanthanide bioprobes, which are suitable in complicated bioassay systems in which concentration is variable. PMID:25791467

  4. Actinide and lanthanide separation process (ALSEP)

    SciTech Connect

    Guelis, Artem V.

    2013-01-15

    The process of the invention is the separation of minor actinides from lanthanides in a fluid mixture comprising, fission products, lanthanides, minor actinides, rare earth elements, nitric acid and water by addition of an organic chelating aid to the fluid; extracting the fluid with a solvent comprising a first extractant, a second extractant and an organic diluent to form an organic extractant stream and an aqueous raffinate. Scrubbing the organic stream with a dicarboxylic acid and a chelating agent to form a scrubber discharge. The scrubber discharge is stripped with a simple buffering agent and a second chelating agent in the pH range of 2.5 to 6.1 to produce actinide and lanthanide streams and spent organic diluents. The first extractant is selected from bis(2-ethylhexyl)hydrogen phosphate (HDEHP) and mono(2-ethylhexyl)2-ethylhexyl phosphonate (HEH(EHP)) and the second extractant is selected from N,N,N,N-tetra-2-ethylhexyl diglycol amide (TEHDGA) and N,N,N',N'-tetraoctyl-3-oxapentanediamide (TODGA).

  5. Nanometrization of Lanthanide-Based Coordination Polymers.

    PubMed

    Neaime, Chrystelle; Daiguebonne, Carole; Calvez, Guillaume; Freslon, Stéphane; Bernot, Kevin; Grasset, Fabien; Cordier, Stéphane; Guillou, Olivier

    2015-11-23

    Heteronuclear lanthanide-based coordination polymers are microcrystalline powders, the luminescence properties of which can be precisely tuned by judicious choice of the rare-earth ions. In this study, we demonstrate that such materials can also be obtained as stable solutions of nanoparticles in non-toxic polyols. Bulk powders of the formula [Ln2-2x Ln'2x (bdc)3 ⋅4 H2 O]∞ (where H2 bdc denotes 1,4-benzene-dicarboxylic acid, 0≤x≤1, and Ln and Ln' denote lanthanide ions of the series La to Tm plus Y) afford nanoparticles that have been characterized by dynamic light-scattering (DLS) and transmission electron microscopy (TEM) measurements. Their luminescence properties are similar to those of the bulk materials. Stabilities versus time and versus dilution with another solvent have been studied. This study has revealed that it is possible to tune the size of the nanoparticles. This process offers a reliable means of synthesizing suspensions of nanoparticles with tunable luminescence properties and tunable size distributions in a green solvent (glycerol). The process is also extendable to other coordination polymers and other solvents (ethylene glycol, for example). It constitutes a new route for the facile solubilization of lanthanide-based coordination polymers.

  6. f-state luminescence of lanthanide and actinide ions in solution

    SciTech Connect

    Beitz, J.V.

    1993-09-01

    Detailed studies of the luminescence of aquated Am{sup 3+} are presented in the context of prior lanthanide and actinide ion work. The luminescing state of aquated Am{sup 3+} is confirmed to be {sup 5}D{sub l} based on observed emission and excitation spectra. The luminescence lifetime of Am{sup 3+} in H{sub 2}O solution is (22 {plus_minus} 3) ns and (155 {plus_minus} 4) ns in D{sub 2}O solution at 295 K. Judd-Ofelt transition intensity theory qualitatively describes the observed Am{sup 3+} relative integrated fluorescence intensities. Recent luminescence studies on complexed trivalent f-element ions in solution are reviewed as to the similarities and differences between lanthanide ion 4f state and actinide ion 5f state properties.

  7. Synthesis and lanthanide coordination chemistry of trifluoromethyl derivatives of phosphinoylmethyl pyridine N-oxides

    SciTech Connect

    Pailloux, Sylvie; Shirima, Cornel Edicome; Duesler, Eileen N.; Smith, Karen Ann; Paine, Robert T.; Klaehn, John D.; McIlwain, Michael E; Hay, Benjamin

    2009-01-01

    A synthetic route for the formation of 2-[bis-(2-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine N-oxide (1c) and 2-[bis-(3,5-trifluoromethyl-phenyl)-phosphinoylmethyl]-pyridine N-oxide (1d) was developed and the new ligands characterized by spectroscopic methods and single crystal X-ray diffraction analyses. The coordination chemistry of the ligands was examined with early and late lanthanide ions. The molecular structure of one complex, [Yb(1c)(NO3)3(DMF)](DMF)(H2O)0.5, was determined by single crystal X-ray diffraction methods and the ligand found to coordinate in a bidentate fashion. This coordination chemistry is compared against lanthanide coordination chemistry observed for the related ligand, [Ph2P(O)CH2] C5H4NO.

  8. Photocontrolled Reversible Luminescent Lanthanide Molecular Switch Based on a Diarylethene-Europium Dyad.

    PubMed

    Cheng, Hong-Bo; Hu, Guo-Fei; Zhang, Zhan-Hui; Gao, Liang; Gao, Xingfa; Wu, Hai-Chen

    2016-08-15

    A new europium complex coordinated between a Eu(III) ion and an unsymmetrical diarylperfluorocyclopentene yields a light-controlled diarylethene-europium dyad, DAE@TpyEu(tta)3, whose photophysical properties can be reversibly switched by optical stimuli. When DAE@TpyEu(tta)3 is exposed to 365 nm UV light, an efficient intramolecular photochromic fluorescence resonance energy transfer (pc-FRET) occurs between the emission of the Eu(3+) donor (D) and the absorption of the diarylethene acceptor (A) in closed-form DAE@TpyEu(tta)3 accompanied by luminescence quenching. However, the pc-FRET process could be effectively inhibited by visible light (λ > 600 nm) irradiation, and the lanthanide emission of DAE@TpyEu(tta)3 is rapidly recovered. Furthermore, this luminescent lanthanide molecular switch could serve as a highly reliable and sensitive "turn on" fluorescent marker in living cells irradiated by red light without any optical interference. PMID:27447742

  9. Selective chelation and extraction of lanthanides and actinides with supercritical fluids

    SciTech Connect

    Brauer, R.D.; Carleson, T.E.; Harrington, J.D.; Jean, F.; Jiang, H.; Lin, Y.; Wai, C.M.

    1994-01-01

    This report is made up of three independent papers: (1) Supercritical Fluid Extraction of Thorium and Uranium with Fluorinated Beta-Diketones and Tributyl Phosphate, (2) Supercritical Fluid Extraction of Lanthanides with Beta-Diketones and Mixed Ligands, and (3) A Group Contribution Method for Predicting the Solubility of Solid Organic Compounds in Supercritical Carbon Dioxide. Experimental data are presented demonstrating the successful extraction of thorium and uranium using fluorinated beta-diketones to form stable complexes that are extracted with supercritical carbon dioxide. The conditions for extracting the lanthanide ions from liquid and solid materials using supercritical carbon dioxide are presented. In addition, the Peng-Robison equation of state and thermodynamic equilibrium are used to predict the solubilities of organic solids in supercritical carbon dioxide from the sublimation pressure, critical properties, and a centric factor of the solid of interest.

  10. Improved method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E.P.; Kalina, D.G.; Kaplan, L.; Mason, G.W.

    1983-07-26

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions uses a new series of neutral bi-functional extractants, the alkyl(phenyl)-N,N-dialkylcarbamoylmethylphosphine oxides. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high-level nuclear reprocessing waste solutions.

  11. Trivalent Lanthanide/Actinide Separation Using Aqueous-Modified TALSPEAK Chemistry

    SciTech Connect

    Travis S. Grimes; Richard D. Tillotson; Leigh R. Martin

    2014-05-01

    TALSPEAK is a liquid/liquid extraction process designed to separate trivalent lanthanides (Ln3+) from minor actinides (MAs) Am3+ and Cm3+. Traditional TALSPEAK organic phase is comprised of a monoacidic dialkyl bis(2-ethylhexyl)phosphoric acid extractant (HDEHP) in diisopropyl benzene (DIPB). The aqueous phase contains a soluble aminopolycarboxylate diethylenetriamine-N,N,N’,N”,N”-pentaacetic acid (DTPA) in a concentrated (1.0-2.0 M) lactic acid (HL) buffer with the aqueous acidity typically adjusted to pH 3.0. TALSPEAK balances the selective complexation of the actinides by DTPA against the electrostatic attraction of the lanthanides by the HDEHP extractant to achieve the desired trivalent lanthanide/actinide group separation. Although TALSPEAK is considered a successful separations scheme, recent fundamental studies have highlighted complex chemical interactions occurring in the aqueous and organic phases during the extraction process. Previous attempts to model the system have shown thermodynamic models do not accurately predict the observed extraction trends in the p[H+] range 2.5-4.8. In this study, the aqueous phase is modified by replacing the lactic acid buffer with a variety of simple and longer-chain amino acid buffers. The results show successful trivalent lanthanide/actinide group separation with the aqueous-modified TALSPEAK process at pH 2. The amino acid buffer concentrations were reduced to 0.5 M (at pH 2) and separations were performed without any effect on phase transfer kinetics. Successful modeling of the aqueous-modified TALSPEAK process (p[H+] 1.6-3.1) using a simplified thermodynamic model and an internally consistent set of thermodynamic data is presented.

  12. Lanthanide-based imaging of protein-protein interactions in live cells.

    PubMed

    Rajendran, Megha; Yapici, Engin; Miller, Lawrence W

    2014-02-17

    In order to deduce the molecular mechanisms of biological function, it is necessary to monitor changes in the subcellular location, activation, and interaction of proteins within living cells in real time. Förster resonance energy-transfer (FRET)-based biosensors that incorporate genetically encoded, fluorescent proteins permit high spatial resolution imaging of protein-protein interactions or protein conformational dynamics. However, a nonspecific fluorescence background often obscures small FRET signal changes, and intensity-based biosensor measurements require careful interpretation and several control experiments. These problems can be overcome by using lanthanide [Tb(III) or Eu(III)] complexes as donors and green fluorescent protein (GFP) or other conventional fluorophores as acceptors. Essential features of this approach are the long-lifetime (approximately milliseconds) luminescence of Tb(III) complexes and time-gated luminescence microscopy. This allows pulsed excitation, followed by a brief delay, which eliminates nonspecific fluorescence before the detection of Tb(III)-to-GFP emission. The challenges of intracellular delivery, selective protein labeling, and time-gated imaging of lanthanide luminescence are presented, and recent efforts to investigate the cellular uptake of lanthanide probes are reviewed. Data are presented showing that conjugation to arginine-rich, cell-penetrating peptides (CPPs) can be used as a general strategy for the cellular delivery of membrane-impermeable lanthanide complexes. A heterodimer of a luminescent Tb(III) complex, Lumi4, linked to trimethoprim and conjugated to nonaarginine via a reducible disulfide linker rapidly (∼10 min) translocates into the cytoplasm of Maden Darby canine kidney cells from the culture medium. With this reagent, the intracellular interaction between GFP fused to FK506 binding protein 12 (GFP-FKBP12) and the rapamycin binding domain of mTOR fused to Escherichia coli dihydrofolate reductase (FRB

  13. Lanthanide mixed-ligand complexes of the [Ln(CAPh)3(Phen)] and [LaxEu1-x(CAPh)3(Phen)] (CAPh = carbacylamidophosphate) type. A comparative study of their spectral properties.

    PubMed

    Litsis, Olena O; Ovchynnikov, Vladimir A; Scherbatskii, Vasyl P; Nedilko, Sergiy G; Sliva, Tatiana Yu; Dyakonenko, Viktoriya V; Shishkin, Oleg V; Davydov, Valentine I; Gawryszewska, Paula; Amirkhanov, Vladimir M

    2015-09-21

    A series of complexes Ln(Pip)3(Phen) (Ln(iii) = La, Ce-Nd, Sm-Lu, Y; HPip (CAPh type ligand) = 2,2,2-trichloro-N-(dipiperidin-1-yl-phosphoryl)acetamide, Phen = 1,10-phenanthroline) has been synthesized. The lanthanum(iii) doped europium(iii) complexes ([LaxEu1-x(Pip)3(Phen)], x = 0.99, 0.95, 0.50) have been obtained by the co-crystallization method. The complexes have been characterized by means of X-ray diffraction, IR, (1)H and (31)P-NMR and absorption spectroscopy. Emission and excitation luminescence spectra were recorded at 295 and 77 K. The lifetime values (τ) for the emission of all europium complexes were determined. The (5)D0 luminescence quantum efficiency is 73-89%. The symmetries of the nearest europium surrounding in pure and doped complexes were evaluated from the Stark splitting of (5)D0-(7)FJ transitions. Crystal structures of [Ln(Pip)3(Phen)] (Ln = Nd (1), Eu (2) and Tb (3)) have been determined. Lattice parameters of the [Ln(Pip)3(Phen)] (Ln = Tb, Yb) and the doped [LaxEu1-x(Pip)3(Phen)] (x = 0.99, 0.95, 0.50) complexes have been measured. The presence of four polymorphs within a number of rare earth elements has been estimated: two in triclinic (Ln1 = La, Nd; Ln2 = Eu), one in the monoclinic (Ln3 = Tb) and one in the rhombic (Ln4 = Tb, Yb) symmetry. Complex 3 can be obtained in two crystal modifications: monoclinic and orthorhombic ones.

  14. Lanthanide mixed-ligand complexes of the [Ln(CAPh)3(Phen)] and [LaxEu1-x(CAPh)3(Phen)] (CAPh = carbacylamidophosphate) type. A comparative study of their spectral properties.

    PubMed

    Litsis, Olena O; Ovchynnikov, Vladimir A; Scherbatskii, Vasyl P; Nedilko, Sergiy G; Sliva, Tatiana Yu; Dyakonenko, Viktoriya V; Shishkin, Oleg V; Davydov, Valentine I; Gawryszewska, Paula; Amirkhanov, Vladimir M

    2015-09-21

    A series of complexes Ln(Pip)3(Phen) (Ln(iii) = La, Ce-Nd, Sm-Lu, Y; HPip (CAPh type ligand) = 2,2,2-trichloro-N-(dipiperidin-1-yl-phosphoryl)acetamide, Phen = 1,10-phenanthroline) has been synthesized. The lanthanum(iii) doped europium(iii) complexes ([LaxEu1-x(Pip)3(Phen)], x = 0.99, 0.95, 0.50) have been obtained by the co-crystallization method. The complexes have been characterized by means of X-ray diffraction, IR, (1)H and (31)P-NMR and absorption spectroscopy. Emission and excitation luminescence spectra were recorded at 295 and 77 K. The lifetime values (τ) for the emission of all europium complexes were determined. The (5)D0 luminescence quantum efficiency is 73-89%. The symmetries of the nearest europium surrounding in pure and doped complexes were evaluated from the Stark splitting of (5)D0-(7)FJ transitions. Crystal structures of [Ln(Pip)3(Phen)] (Ln = Nd (1), Eu (2) and Tb (3)) have been determined. Lattice parameters of the [Ln(Pip)3(Phen)] (Ln = Tb, Yb) and the doped [LaxEu1-x(Pip)3(Phen)] (x = 0.99, 0.95, 0.50) complexes have been measured. The presence of four polymorphs within a number of rare earth elements has been estimated: two in triclinic (Ln1 = La, Nd; Ln2 = Eu), one in the monoclinic (Ln3 = Tb) and one in the rhombic (Ln4 = Tb, Yb) symmetry. Complex 3 can be obtained in two crystal modifications: monoclinic and orthorhombic ones. PMID:26239675

  15. Spectroscopic Study of the Use of Lanthanide Metalloporphyrins as Sensors for Benzene and Acetonitrile Detection in Aqueous Studies

    NASA Astrophysics Data System (ADS)

    Crawford, Carlos Lemarr, Jr.

    This work entails the research on lanthanide metalloporphyrins for their potential use as chemical sensors for benzene and acetonitrile. This research is of importance due to the health implications that benzene and acetonitrile cause; benzene is a known carcinogen and acetonitrile is a known lung irritant. The use of UV-Vis spectroscopy, Fluorescence spectroscopy, Gaussian DFT, and X-ray diffraction crystallography were used in the characterization and analysis of the lanthanide porphyrin complexes. Europium, terbium, dysprosium, cerium, and gadolinium were the lanthanides used in conjunction with 5,10,15,20-tetraphenylporphyrin, TPP and 5,10,15,20-tetrakissulfonato porphyrin, TBSP. Based on the luminescence spectroscopy and UV-Vis spectroscopy data, an aqueous sensor for acetonitrile and benzene was shown to be promising. Among the compounds studied, EuTPP and DyTPP complexes exposed to sodium hydroxide showed promising results for sensing acetonitrile due to significant narrowing of the soret band and the decrease of Q bands in the UV-Vis spectra, along with the blue shifting of luminescence emission spectra. On the other hand, the CeTPP and EuTPP solutions show promise as benzene sensors due to the blue shifting of emission luminescence and variation in intensity. Based on the lanthanide TBSP complexes, TbTBSP was shown to be a promising sensor for acetonitrile due to the narrow soret band, decreased Q bands, and blue shifted emission spectra. EuTBSP, DyTBSP, and TbTBSP were shown to be promising for benzene sensors. Benzene stabilized the TBSP at a higher energy state, S2, to facilitate the energy transfer to the lanthanide ions.

  16. Multicoordinate ligands for actinide/lanthanide separations.

    PubMed

    Dam, Henk H; Reinhoudt, David N; Verboom, Willem

    2007-02-01

    In nuclear waste treatment processes there is a need for improved ligands for the separation of actinides (An(III)) and lanthanides (Ln(III)). Several research groups are involved in the design and synthesis of new An(III) ligands and in the confinement of these and existing An(III) ligands onto molecular platforms giving multicoordinate ligands. The preorganization of ligands considerably improves the An(III) extraction properties, which are largely dependent on the solubility and rigidity of the platform. This tutorial review summarizes the most important An(III) ligands with emphasis on the preorganization strategy using (macrocyclic) platforms.

  17. Spectroscopic investigations of lanthanide ion binding to nucleic acids.

    PubMed

    Morrow, Janet R; Andolina, Christopher M

    2012-01-01

    Luminescent lanthanide (Ln(III)) ions are valuable spectroscopic probes for metal ion binding sites in nucleic acids. In this chapter, we briefly review Ln(III) luminescence and the information available from these experiments. An emphasis is placed on direct excitation Eu(III) spectroscopy as a tool. Eu(III) excitation spectroscopy is used to show that solutions containing micromolar Eu(III), 100 mM NaCl, and 20 mM MES buffer contain predominantly a mononuclear Eu(III) aqua complex and an Eu(III) hydroxide complexes. The binding of these species to various RNA and DNA sequences are monitored by using Eu(III) excitation spectroscopy. Eu(III) luminescence lifetime data shows that the Eu(III) ion typically loses 1-3 water molecules to form innersphere complexes with RNA and DNA that contain tandem base pair mismatches or hairpin loops. In addition, early studies that used nucleobase-sensitized Eu(III) or Tb(III) luminescence within transfer RNA or in the hammerhead ribozyme are presented. Luminescence resonance energy transfer studies are shown to be useful for determining distances between bound Ln(III) ion and organic fluorophores or between two different Ln(III) ions. To supplement luminescence data, the binding sites of paramagnetic Ln(III) ions are determined by monitoring the chemical shifts of nucleotide protons. Binding sites are identified by following the protons that are influenced by the Ln(III) pseudo-contact shift.

  18. Solvent systems combining neutral and acidic extractants for separating trivalent lanthanides from the transuranic elements.

    SciTech Connect

    Lumetta, G. J.; Gelis, A. V.; Vandegrift, G. F.; Chemical Sciences and Engineering Division; PNL

    2010-01-01

    This paper is a review of recent publications that have focused on combined extractant systems for separating trivalent actinides from the lanthanides. These mixed solvent systems combine an acidic extractant with a neutral extractant to achieve the actinide/lanthanide separation. Depending on the neutral extractant used, three categorizations of systems can be considered, including combinations of acidic extractants with 1 diamides, 2 carbamoylmethylphosphine oxides, and 3 polydentate nitrogen-donor ligands. This review of relevant publications indicates that, although there is significant potential for practical exploitation of mixed neutral/acidic extractant systems to achieve a single-step separation of trivalent actinides from acidic high-level waste solutions, the fundamental chemistry underlying these combined systems is not yet well understood. For example, although there is strong evidence suggesting that adducts form between the neutral and acidic extractants, the nature of these adducts generally is not known. Likewise, the structures of the mixed complexes formed between the metal ions and the two different extractants are not fully understood. Research into these basic phenomena likely will provide clues about how to design practical mixed-extractant systems that can be used to efficiently separate the transuranic elements from the lanthanides and other components of irradiated fuel.

  19. Investigation of aggregation in solvent extraction of lanthanides by acidic extractants (organophosphorus and naphthenic acid)

    USGS Publications Warehouse

    Zhou, N.; Wu, J.; Yu, Z.; Neuman, R.D.; Wang, D.; Xu, G.

    1997-01-01

    Three acidic extractants (I) di(2-ethylhexyl) phosphoric acid (HDEHP), (II) 2-ethylhexyl phosphonic acid mono-2-ethylhexyl ester (HEHPEHE) and (III) naphthenic acid were employed in preparing the samples for the characterization of the coordination structure of lanthanide-extractant complexes and the physicochemical nature of aggregates formed in the organic diluent of the solvent extraction systems. Photo correlation spectroscopy (PCS) results on the aggregates formed by the partially saponified HDEHP in n-heptane showed that the hydrodynamic radius of the aggregates was comparable to the molecular dimensions of HDEHP. The addition of 2-octanol into the diluent, by which the mixed solvent was formed, increased the dimensions of the corresponding aggregates. Aggregates formed from the lanthanide ions and HDEHP in the organic phase of the extraction systems were found very unstable. In the case of naphthenic acid, PCS data showed the formation of w/o microemulsion from the saponified naphthenic acid in the mixed solvent. The extraction of lanthanides by the saponified naphthenic acid in the mixed solvent under the given experimental conditions was a process of destruction of the w/o microemulsion. A possible mechanism of the breakdown of the w/o microemulsion droplets is discussed.

  20. Syntheses, structures and photoluminescence of lanthanide-organic frameworks assembled from multifunctional N,O-donor ligand

    SciTech Connect

    Che, Guang-Bo; Liu, Shu-Yu; Zhang, Qing; Liu, Chun-Bo; Zhang, Xing-Jing

    2015-05-15

    Four new lanthanide complexes [Ln(O–NCP){sub 2}(NO{sub 3})]{sub n} based on multifunctional N,O-donor ligand 2-(2-carboxyphenyl)imidazo(4,5-f)-(1,10)phenanthroline (O–HNCP) and Ln(NO{sub 3}){sub 3}·6H{sub 2}O (Ln=Nd(1), La(2), Sm(3), Eu(4)) have been achieved under hydrothermal conditions and characterized by elemental analyses, infrared spectra and single crystal X-ray diffraction. Structural analyses revealed that all of these four complexes possess similar two-dimensional layer structures. In addition, thermal stability and luminescent properties of these complexes were also investigated. - Graphical abstract: A series of lanthanide(III) coordination polymers with intriguing structures based on 2-(2-carboxyphenyl)imidazo(4,5-f)-(1,10)phenanthroline ligand have been hydrothermally synthesized. The thermal stabilities and photoluminescence properties of these complexes have been investigated. - Highlights: • Four lanthanide(III) complexes have been hydrothermally synthesized. • The N,O-donor O–HNCP was used as the ligand. • TGA and PL properties of complexes 1–4 have been investigated.

  1. The Crystal Structure of Lanthanide Zirconates

    NASA Astrophysics Data System (ADS)

    Clements, Richard; Kennedy, Brendan; Ling, Christopher; Stampfl, Anton P. J.

    2010-03-01

    The lanthanide zirconates of composition Ln2Zr2O7 (Ln = La-Gd) are of interest for use in inert matrix fuels and nuclear wasteforms. The series undergoes a pyrochlore to fluorite phase transition as a function of the Ln atomic radii. The phase transition has been attributed to disordering of both the cation and the anion [1]. We have undertaken a synthesis of the lanthanide zirconate series Ln2Zr2O7 (Ln = La-Gd), Ln0.2Zr0.8O1.9 (Ln = Tb-Yb) and NdxHo2-xZr2O7 (0

  2. Ion exchange in hydroxyapatite with lanthanides.

    PubMed

    Cawthray, Jacqueline F; Creagh, A Louise; Haynes, Charles A; Orvig, Chris

    2015-02-16

    Naturally occurring hydroxyapatite, Ca5(PO4)3(OH) (HAP), is the main inorganic component of bone matrix, with synthetic analogues finding applications in bioceramics and catalysis. An interesting and valuable property of both natural and synthetic HAP is the ability to undergo cationic and anionic substitution. The lanthanides are well-suited for substitution for the Ca(2+) sites within HAP, because of their similarities in ionic radii, donor atom requirements, and coordination geometries. We have used isothermal titration calorimetry (ITC) to investigate the thermodynamics of ion exchange in HAP with a representative series of lanthanide ions, La(3+), Sm(3+), Gd(3+), Ho(3+), Yb(3+) and Lu(3+), reporting the association constant (Ka), ion-exchange thermodynamic parameters (ΔH, ΔS, ΔG), and binding stoichiometry (n). We also probe the nature of the La(3+):HAP interaction by solid-state nuclear magnetic resonance ((31)P NMR), X-ray diffraction (XRD), and inductively coupled plasma-optical emission spectroscopy (ICP-OES), in support of the ITC results. PMID:25594577

  3. Picosecond dynamics from lanthanide chloride melts

    NASA Astrophysics Data System (ADS)

    Kalampounias, Angelos G.

    2012-12-01

    The picosecond dynamics of molten lanthanide chlorides is studied by means of vibrational spectroscopy. Polarized Raman spectra of molten LaCl3, NdCl3, GdCl3, DyCl3, HoCl3 and YCl3 are fitted to a model enabling to obtain the times of vibrational dephasing, tν and vibrational frequency modulation tω. Our aim is to find possible sensitive indicators of short-time dynamics. It has been found that all lanthanide chlorides exhibit qualitative similarities in the vibrational relaxation and frequency modulation times in the molten state. It appears that the vibrational correlation functions of all melts comply with the Rothschild approach assuming that the environmental modulation is described by a stretched exponential decay. The evolution of the dispersion parameter α indicates the deviation of the melts from the model simple liquid and the similar local environment in which the oscillator is placed and with which it is coupled. The "packing" of the anions around central La3+ cation seems to be the key factor for the structure and the dynamics of the melts. The results are discussed in the framework of the current phenomenological status of the field.

  4. Carbon-bridged bis(phenolato)lanthanide alkoxides: syntheses, structures, and their application in the controlled polymerization of epsilon-caprolactone.

    PubMed

    Yao, Yingming; Xu, Xiaoping; Liu, Bao; Zhang, Yong; Shen, Qi; Wong, Wing-Tak

    2005-07-11

    A convenient method for the synthesis of lanthanide alkoxo complexes supported by a carbon-bridged bis(phenolate) ligand 2,2'-methylenebis(6-tert-butyl-4-methylphenoxo) (MBMP2-) is described. The reaction of (C5H5)3Nd with MBMPH2 in a 1:1 molar ratio in THF gave the bis(phenolato)lanthanide complex (C5H5)Nd(MBMP)(THF)2 (1) in a nearly quantitative yield. Complex 1 further reacted with 1 equiv of 2-propanol in THF to yield the bis(phenolato)lanthanide isopropoxide [(MBMP)2Nd(mu-OPr(i))(THF)2]2 (2) in high yield. Complex 2 can also be synthesized by the direct reaction of (C5H5)3Nd with MBMPH2 in a 1:1 molar ratio and then with 1 equiv of 2-propanol in situ in THF. Thus, the analogue bis(phenolato)lanthanide alkoxides [(MBMP)2Ln(mu-OR)(THF)2]2 [R = Pr(i), Ln = Yb (3); R = Me, Ln = Nd (4), Yb (5); R = CH2Ph, Ln = Nd (6), Yb (7)] were obtained by the reactions of (C5H5)3Ln (Ln = Nd, Yb) with MBMPH2 and then with 2-propanol, methanol, or benzyl alcohol, respectively. The ytterbium complex {[(MBMP)2Yb(THF)2]2(mu-OCH2Ph)(mu-OH)} (8) was also isolated as a byproduct. The single-crystal structural analyses of complexes 1-3 and 8 revealed that the coordination geometry around lanthanide metal can be best described as a distorted tetrahedron in complex 1 and as a distorted octahedron in complexes 2, 3, and 8. A O-H...Yb agostic interaction was observed in complex 8. Complexes 2-7 were shown to be efficient catalysts for the controlled polymerization of epsilon-caprolactone. PMID:15998042

  5. Carbon-bridged bis(phenolato)lanthanide alkoxides: syntheses, structures, and their application in the controlled polymerization of epsilon-caprolactone.

    PubMed

    Yao, Yingming; Xu, Xiaoping; Liu, Bao; Zhang, Yong; Shen, Qi; Wong, Wing-Tak

    2005-07-11

    A convenient method for the synthesis of lanthanide alkoxo complexes supported by a carbon-bridged bis(phenolate) ligand 2,2'-methylenebis(6-tert-butyl-4-methylphenoxo) (MBMP2-) is described. The reaction of (C5H5)3Nd with MBMPH2 in a 1:1 molar ratio in THF gave the bis(phenolato)lanthanide complex (C5H5)Nd(MBMP)(THF)2 (1) in a nearly quantitative yield. Complex 1 further reacted with 1 equiv of 2-propanol in THF to yield the bis(phenolato)lanthanide isopropoxide [(MBMP)2Nd(mu-OPr(i))(THF)2]2 (2) in high yield. Complex 2 can also be synthesized by the direct reaction of (C5H5)3Nd with MBMPH2 in a 1:1 molar ratio and then with 1 equiv of 2-propanol in situ in THF. Thus, the analogue bis(phenolato)lanthanide alkoxides [(MBMP)2Ln(mu-OR)(THF)2]2 [R = Pr(i), Ln = Yb (3); R = Me, Ln = Nd (4), Yb (5); R = CH2Ph, Ln = Nd (6), Yb (7)] were obtained by the reactions of (C5H5)3Ln (Ln = Nd, Yb) with MBMPH2 and then with 2-propanol, methanol, or benzyl alcohol, respectively. The ytterbium complex {[(MBMP)2Yb(THF)2]2(mu-OCH2Ph)(mu-OH)} (8) was also isolated as a byproduct. The single-crystal structural analyses of complexes 1-3 and 8 revealed that the coordination geometry around lanthanide metal can be best described as a distorted tetrahedron in complex 1 and as a distorted octahedron in complexes 2, 3, and 8. A O-H...Yb agostic interaction was observed in complex 8. Complexes 2-7 were shown to be efficient catalysts for the controlled polymerization of epsilon-caprolactone.

  6. Some aspects of the geochemistry of yttrium and the lanthanides

    USGS Publications Warehouse

    Fleischer, Michael

    1965-01-01

    Recent data on the relative abundances of the lanthanides and yttrium in meteorites, basaltic rocks, granitic rocks and sedimentary rocks are reviewed. It is shown that the data are inadequate to substantiate or to disprove Taylor's derivation from these data of a 1:1 abundance ratio of basaltic to granitic rocks in the continental crust. Graphs are given to illustrate the variation of lanthanides in minerals with paragenesis. Both the paragenesis and the crystal chemistry of minerals affect the composition of the lanthanides.

  7. Lanthanide-doped upconverting phosphors for bioassay and therapy

    NASA Astrophysics Data System (ADS)

    Guo, Huichen; Sun, Shiqi

    2012-10-01

    Lanthanide-doped fluorescent materials have gained increasing attention in recent years due to their unique luminescence properties which have led to their use in wide-ranging fields including those of biological applications. Aside from being used as agents for in vivo imaging, lanthanide-doped fluorescent materials also present many advantages for use in bioassays and therapy. In this review, we summarize the applications of lanthanide-doped up-converting phosphors (UCPs) in protein and gene detection, as well as in photodynamic and gene therapy in recent years, and outline their future potential in biological applications. The current report could serve as a reference for researchers in relevant fields.

  8. Solution thermodynamic stability of complexes formed with the octadentate hydroxypyridinonate ligand 3,4,3-LI(1,2-HOPO): a critical feature for efficient chelation of lanthanide(IV) and actinide(IV) ions.

    PubMed

    Deblonde, Gauthier J-P; Sturzbecher-Hoehne, Manuel; Abergel, Rebecca J

    2013-08-01

    The solution thermodynamics of water-soluble complexes formed between Ce(III), Ce(IV), Th(IV) and the octadentate chelating agent 3,4,3-LI(1,2-HOPO) were investigated. Several techniques including spectrofluorimetric and automated spectrophotometric titrations were used to overcome the slow spontaneous oxidation of Ce(III) complexes yielding to stability constants of log β110 = 17.4 ± 0.5, log β11-1 = 8.3 ± 0.4 and log β111 = 21.2 ± 0.4 for [Ce(III)(3,4,3-LI(1,2-HOPO))](-), [Ce(III)(3,4,3-LI(1,2-HOPO)(OH)](2-), and [Ce(III)(3,4,3-LI(1,2-HOPO)H], respectively. Using the spectral properties of the hydroxypyridinonate chelator in ligand competition titrations against nitrilotriacetic acid, the stability constant log β110 = 41.5 ± 0.5 was determined for [Ce(IV)(3,4,3-LI(1,2-HOPO))]. Finally, the extraordinarily stable complex [Ce(IV)(3,4,3-LI(1,2-HOPO))] was used in Th(IV) competition titrations, resulting in a stability constant of log β110 = 40.1 ± 0.5 for [Th(IV)3,4,3-LI(1,2-HOPO))]. These experimental values are in excellent agreement with previous estimates, they are discussed with respect to the ionic radius and oxidation state of each cationic metal, and allow predictions on the stability of other actinide complexes including [U(IV)(3,4,3-LI(1,2-HOPO))], [Np(IV)(3,4,3-LI(1,2-HOPO))], and [Pu(IV)(3,4,3-LI(1,2-HOPO))]. Comparisons with the standard ligand diethylenetriamine pentaacetic acid (DTPA) provide a thermodynamic basis for the observed significantly higher efficacy of 3,4,3-LI(1,2-HOPO) as an in vivo actinide decorporation agent. PMID:23855806

  9. Solution thermodynamic stability of complexes formed with the octadentate hydroxypyridinonate ligand 3,4,3-LI(1,2-HOPO): A critical feature for efficient chelation of lanthanide(IV) and actinide(IV) ions

    PubMed Central

    Deblonde, Gauthier J-P.; Sturzbecher-Hoehne, Manuel; Abergel, Rebecca J.

    2013-01-01

    The solution thermodynamics of water soluble complexes formed between Ce(III), Ce(IV), Th(IV) and the octadentate chelating agent 3,4,3-LI(1,2-HOPO) were investigated. Several techniques including spectrofluorimetric and automated spectrophotometric titrations were used to overcome the slow spontaneous oxidation of Ce(III) complexes yielding to stability constants of log β110 = 17.4 ± 0.5, log β11-1 = 8.3 ± 0.4 and log β111 = 21.2 ± 0.4 for [Ce(III)(3,4,3-LI(1,2-HOPO))]−, [Ce(III)(3,4,3-LI(1,2-HOPO)(OH)]2− and [Ce(III)(3,4,3-LI(1,2-HOPO)H], respectively. Using the spectral properties of the hydroxypyridinonate chelator in ligand competition titrations against nitrilotriacetic acid, the stability constant log β110 = 41.5 ± 0.5 was determined for [Ce(IV)(3,4,3-LI(1,2-HOPO))]. Finally, the extraordinarily stable complex [Ce(IV)(3,4,3-LI(1,2-HOPO))] was used in Th(IV) competition titrations, resulting in a stability constant of log β110 = 40.1 ± 0.5 for [Th(IV)3,4,3-LI(1,2-HOPO))]. These experimental values are in excellent agreement with previous estimates, they are discussed with respect to the ionic radius and oxidation state of each cationic metal and allow predictions on the stability of other actinide complexes including [U(IV)(3,4,3-LI(1,2-HOPO))], [Np(IV)(3,4,3-LI(1,2-HOPO))] and [Pu(IV)(3,4,3-LI(1,2-HOPO))]. Comparisons with the standard ligand diethylenetriamine pentaacetic acid (DTPA) provide a thermodynamic basis for the observed significantly higher efficacy of 3,4,3-LI(1,2-HOPO) as an in vivo actinide decorporation agent. PMID:23855806

  10. Lanthanide Tetrazolate Complexes Combining Single-Molecule Magnet and Luminescence Properties: The Effect of the Replacement of Tetrazolate N3 by β-Diketonate Ligands on the Anisotropy Energy Barrier.

    PubMed

    Jiménez, Juan-Ramón; Díaz-Ortega, Ismael F; Ruiz, Eliseo; Aravena, Daniel; Pope, Simon J A; Colacio, Enrique; Herrera, Juan Manuel

    2016-10-01

    Three new sets of mononuclear Ln(III) complexes of general formulas [LnL3 ]⋅CH3 OH [Ln(III) =Yb (1), Er (2), Dy (3), Gd (4), and Eu (5)], [LnL2 (tmh)(CH3 OH)]⋅n H2 O⋅m CH3 OH [Ln(III) =Yb (1 b), Er (2 b), Dy (3 b), Gd (4 b)], and [LnL2 (tta)(CH3 OH)]⋅CH3 OH [Ln(III) =Yb (1 c), Er (2 c), Dy (3 c), Gd (4 c)] were prepared by the reaction of Ln(CF3 SO3 )⋅n H2 O salts with the tridentate ligand 2-(tetrazol-5-yl)-1,10-phenanthroline (HL) and, for the last two sets, additionally with the β-diketonate ligands 2,2,6,6-tetramethylheptanoate (tmh) and 2-thenoyltrifluoroacetonate (tta), respectively. In the [LnL3 ]⋅CH3 OH complexes the Ln(III) ions are coordinated to three phenanthroline tetrazolate ligands with an LnN9 coordination sphere. Dynamic ac magnetic measurements on 1-3 reveal that these complexes only exhibit single-molecule magnet (SMM) behavior when an external dc magnetic field is applied, with Ueff values of 11.7 K (1), 16.0 K (2), and 20.2 K (3). When the tridentate phenanthroline tetrazolate ligand is replaced by one molecule of methanol and the β-diketonate ligand tmh (1 b-3 b) or tta (1 c-3 c), a significant increase in Ueff occurs and, in the case of the Dy(III) complexes 3 b and 3 c, out-of-phase χ'' signals below 15 and 10 K, respectively, are observed in zero dc magnetic field. CASSCF+RASSI ab initio calculations performed on the Dy(III) complexes support the experimental results. Thus, for 3 the ground Kramers' doublet is far from being axial and the first excited state is found to be very close in energy to the ground state, so the relaxation barrier in this case is almost negligible. Conversely, for 3 b and 3 c, the ground Kramers' doublet is axial with a small quantum tunneling of the magnetization, and the energy difference between the ground and first Kramers' doublets is much higher, which allows these compounds to behave as SMMs at zero field. Moreover, these calculations support the

  11. Lanthanide Tetrazolate Complexes Combining Single-Molecule Magnet and Luminescence Properties: The Effect of the Replacement of Tetrazolate N3 by β-Diketonate Ligands on the Anisotropy Energy Barrier.

    PubMed

    Jiménez, Juan-Ramón; Díaz-Ortega, Ismael F; Ruiz, Eliseo; Aravena, Daniel; Pope, Simon J A; Colacio, Enrique; Herrera, Juan Manuel

    2016-10-01

    Three new sets of mononuclear Ln(III) complexes of general formulas [LnL3 ]⋅CH3 OH [Ln(III) =Yb (1), Er (2), Dy (3), Gd (4), and Eu (5)], [LnL2 (tmh)(CH3 OH)]⋅n H2 O⋅m CH3 OH [Ln(III) =Yb (1 b), Er (2 b), Dy (3 b), Gd (4 b)], and [LnL2 (tta)(CH3 OH)]⋅CH3 OH [Ln(III) =Yb (1 c), Er (2 c), Dy (3 c), Gd (4 c)] were prepared by the reaction of Ln(CF3 SO3 )⋅n H2 O salts with the tridentate ligand 2-(tetrazol-5-yl)-1,10-phenanthroline (HL) and, for the last two sets, additionally with the β-diketonate ligands 2,2,6,6-tetramethylheptanoate (tmh) and 2-thenoyltrifluoroacetonate (tta), respectively. In the [LnL3 ]⋅CH3 OH complexes the Ln(III) ions are coordinated to three phenanthroline tetrazolate ligands with an LnN9 coordination sphere. Dynamic ac magnetic measurements on 1-3 reveal that these complexes only exhibit single-molecule magnet (SMM) behavior when an external dc magnetic field is applied, with Ueff values of 11.7 K (1), 16.0 K (2), and 20.2 K (3). When the tridentate phenanthroline tetrazolate ligand is replaced by one molecule of methanol and the β-diketonate ligand tmh (1 b-3 b) or tta (1 c-3 c), a significant increase in Ueff occurs and, in the case of the Dy(III) complexes 3 b and 3 c, out-of-phase χ'' signals below 15 and 10 K, respectively, are observed in zero dc magnetic field. CASSCF+RASSI ab initio calculations performed on the Dy(III) complexes support the experimental results. Thus, for 3 the ground Kramers' doublet is far from being axial and the first excited state is found to be very close in energy to the ground state, so the relaxation barrier in this case is almost negligible. Conversely, for 3 b and 3 c, the ground Kramers' doublet is axial with a small quantum tunneling of the magnetization, and the energy difference between the ground and first Kramers' doublets is much higher, which allows these compounds to behave as SMMs at zero field. Moreover, these calculations support the

  12. Evaluating the performance of time-gated live-cell microscopy with lanthanide probes.

    PubMed

    Rajendran, Megha; Miller, Lawrence W

    2015-07-21

    Probes and biosensors that incorporate luminescent Tb(III) or Eu(III) complexes are promising for cellular imaging because time-gated microscopes can detect their long-lifetime (approximately milliseconds) emission without interference from short-lifetime (approximately nanoseconds) fluorescence background. Moreover, the discrete, narrow emission bands of Tb(III) complexes make them uniquely suited for multiplexed imaging applications because they can serve as Förster resonance energy transfer (FRET) donors to two or more differently colored acceptors. However, lanthanide complexes have low photon emission rates that can limit the image signal/noise ratio, which has a square-root dependence on photon counts. This work describes the performance of a wide-field, time-gated microscope with respect to its ability to image Tb(III) luminescence and Tb(III)-mediated FRET in cultured mammalian cells. The system employed a UV-emitting LED for low-power, pulsed excitation and an intensified CCD camera for gated detection. Exposure times of ∼1 s were needed to collect 5-25 photons per pixel from cells that contained micromolar concentrations of a Tb(III) complex. The observed photon counts matched those predicted by a theoretical model that incorporated the photophysical properties of the Tb(III) probe and the instrument's light-collection characteristics. Despite low photon counts, images of Tb(III)/green fluorescent protein FRET with a signal/noise ratio ≥ 7 were acquired, and a 90% change in the ratiometric FRET signal was measured. This study shows that the sensitivity and precision of lanthanide-based cellular microscopy can approach that of conventional FRET microscopy with fluorescent proteins. The results should encourage further development of lanthanide biosensors that can measure analyte concentration, enzyme activation, and protein-protein interactions in live cells. PMID:26200860

  13. Evaluating the performance of time-gated live-cell microscopy with lanthanide probes.

    PubMed

    Rajendran, Megha; Miller, Lawrence W

    2015-07-21

    Probes and biosensors that incorporate luminescent Tb(III) or Eu(III) complexes are promising for cellular imaging because time-gated microscopes can detect their long-lifetime (approximately milliseconds) emission without interference from short-lifetime (approximately nanoseconds) fluorescence background. Moreover, the discrete, narrow emission bands of Tb(III) complexes make them uniquely suited for multiplexed imaging applications because they can serve as Förster resonance energy transfer (FRET) donors to two or more differently colored acceptors. However, lanthanide complexes have low photon emission rates that can limit the image signal/noise ratio, which has a square-root dependence on photon counts. This work describes the performance of a wide-field, time-gated microscope with respect to its ability to image Tb(III) luminescence and Tb(III)-mediated FRET in cultured mammalian cells. The system employed a UV-emitting LED for low-power, pulsed excitation and an intensified CCD camera for gated detection. Exposure times of ∼1 s were needed to collect 5-25 photons per pixel from cells that contained micromolar concentrations of a Tb(III) complex. The observed photon counts matched those predicted by a theoretical model that incorporated the photophysical properties of the Tb(III) probe and the instrument's light-collection characteristics. Despite low photon counts, images of Tb(III)/green fluorescent protein FRET with a signal/noise ratio ≥ 7 were acquired, and a 90% change in the ratiometric FRET signal was measured. This study shows that the sensitivity and precision of lanthanide-based cellular microscopy can approach that of conventional FRET microscopy with fluorescent proteins. The results should encourage further development of lanthanide biosensors that can measure analyte concentration, enzyme activation, and protein-protein interactions in live cells.

  14. From Antenna to Assay: Lessons Learned in Lanthanide Luminescence

    SciTech Connect

    Moore, Evan; Samuel, Amanda; Raymond, Kenneth

    2008-09-25

    Ligand-sensitized luminescent lanthanide(III) complexes are of considerable current interest due to their unique photophysical properties (micro- to millisecond lifetimes, characteristic and narrow emission bands, and large Stokes shifts), which make them well suited to serve as labels in fluorescence-based bioassays. The long-lived Ln(III) emission can be temporally resolved from scattered light and background fluorescence, resulting in vastly enhanced measurement sensitivity. One of the challenges in this field is the design of sensitizing ligands that provide highly emissive Ln(III) complexes that also possess sufficient stability and aqueous solubility required for practical applications. In this account we give an overview of some of the general properties of the trivalent lanthanides and follow with a summary of advances made in our laboratory in the development of highly luminescent Tb(III) and Eu(III) complexes for applications in biotechnology. A focus of our research has been the optimization of these compounds as potential commercial agents for use in Homogeneous Time Resolved Fluorescence (HTRF) technology, the requirements and current use of which will be briefly discussed. Our approach involves developing high-stability octadentate Tb(III) and Eu(III) complexes that rely on all-oxygen donor atoms as well as using multi-chromophore chelates to increase molar absorptivity compared to earlier examples that utilize a single pendant antenna chromophore. We have found that ligands based on 2-hydroxyisophthalamide (IAM) provide exceptionally emissive Tb(III) complexes with quantum yield values up to ca. 60%. Solution thermodynamic studies have indicated that these complexes are stable at the nanomolar concentrations required for commercial assays. Through synthetic modification of the IAM-chromophore, in conjunction with time-dependent density functional theory (TD-DFT) calculations, we have developed a method to predict absorption and emission properties of

  15. Octadentate Cages of Tb(III) 2-Hydroxyisophthalamides: A New Standard for Luminescent Lanthanide Labels

    PubMed Central

    Xu, Jide; Corneillie, Todd M.; Moore, Evan G.; Law, Ga-Lai; Butlin, Nathaniel G.; Raymond, Kenneth N.

    2011-01-01

    The synthesis, structure, and photophysical properties of several Tb(III) complexes with octadentate, macrotricyclic ligands that feature a bicapped topology and 2-hydroxyisopthalamide (IAM) chelating units are reported. These Tb(III) complexes exhibit highly efficient emission (Φtotal ≥ 50%), large extinction coefficients (εmax ≥ 20,000 M−1cm−1), and long luminescence lifetimes (τH2O ≥ 2.45 ms) at dilute concentrations in standard biological buffers. The structure of the methyl-protected ligand was determined by single-crystal X-ray diffraction, and confirms the macrotricyclic structure of the parent ligand; the amide groups of the methyl-protected cage compound generate an anion binding cavity that complexes a chloride anion. Once the ligand is deprotected a conformational change generates a similar cavity, formed by the phenolate and ortho amide oxygen groups that strongly bind lanthanide ions. The Tb(III) complexes thus formed display long term stability, with little if any change in their spectral properties (including lifetime, quantum yield, and emission spectrum) over time or in different chemical environments. Procedures to prepare functionalized derivatives with a terminal amine, carboxylate and N-hydroxysuccinimide groups suitable for derivatization and protein bioconjugation have also been developed. These bifunctional ligands have been covalently attached to a number of different proteins and the terbium complexes' exceptional photophysical properties are retained. These compounds establish a new aqueous stability and quantum yield standard for long-lifetime lanthanide reporters. PMID:22010878

  16. Coupling of the 4f Electrons in Lanthanide Molecules

    SciTech Connect

    Kazhdan, Daniel

    2008-09-01

    (C5Me5)2LnOTf where Ln = La, Ce, Sm, Gd, and Yb have been synthesized and these derivatives are good starting materials for the synthesis of (C5Me5)2LnX derivatives. (C5Me5)2Ln(2,2'-bipyridine), where Ln = La, Ce, Sm, and Gd, along with several methylated bipyridine analogues have been synthesized and their magnetic moments have been measured as a function of temperature. In lanthanum, cerium, and gadolinium complexes the bipyridine ligand ligand is unequivocally the radical anion, and the observed magnetic moment is the result of intramolecular coupling of the unpaired electron on the lanthanide fragment with the unpaired electron on the bipyridine along with the intermolecular coupling between radicals. Comparison with the magnetic moments of the known compounds (C5Me5)2Sm(2,2'-bipyridine) and (C5Me5)2Yb(2,2'-bipyridine) leads to an understanding of the role of the SmII/SmIII and YbII/YbIII couple in the magnetic properties of (C5Me5)2Sm(2,2'-bipyridine) and (C5Me5)2Yb(2,2'-bipyridine). In addition, crystal structures of (C5Me5)2Ln(2,2'-bipyridine) and [(C5Me5)2Ln(2,2'-bipyridine)][BPh4](Ln= Ce and Gd), where the lanthanide is unequivocally in the +3 oxidation state, give the crystallographic characteristics of bipyridine as an anion and as a neutral ligand in the same coordination environment, respectively. Substituted bipyridine ligands coordinated to (C5Me5)2Yb are studied to further understand how the magnetic coupling in (C5Me5)2Yb(2,2'-bipyridine) changes with substitutions. In the cases of (C5Me5)2Yb(5,5'-dimethyl-2,2'-bipyridine) and (C5Me5

  17. Separation of Minor Actinides from Lanthanides by Dithiophosphinic Acid Extractants

    SciTech Connect

    D. R. Peterman; M. R. Greenhalgh; R. D. Tillotson; J. R. Klaehn; M. K. Harrup; T. A. Luther; J. D. Law; L. M. Daniels

    2008-09-01

    The selective extraction of the minor actinides (Am(III) and Cm(III)) from the lanthanides is an important part of advanced reprocessing of spent nuclear fuel. This separation would allow the Am/Cm to be fabricated into targets and recycled to a reactor and the lanthanides to be dispositioned. This separation is difficult to accomplish due to the similarities in the chemical properties of the trivalent actinides and lanthanides. Research efforts at the Idaho National Laboratory have identified an innovative synthetic pathway yielding new regiospecific dithiophosphinic acid (DPAH) extractants. The synthesis provides DPAH derivatives that can address the issues concerning minor actinide separation and extractant stability. For this work, two new symmetric DPAH extractants have been prepared. The use of these extractants for the separation of minor actinides from lanthanides will be discussed.

  18. Lanthanides migration and immobilization in U-Zr nuclear fuels

    NASA Astrophysics Data System (ADS)

    Bozzolo, G.; Hofman, G. L.; Yacout, A. M.; Mosca, H. O.

    2012-06-01

    Redistribution of lanthanides fission products during irradiation and migration to the surface of U-Zr based metallic fuels is a concern due to their interaction with the cladding. The existing remedy for preventing this effect is the introduction of diffusion barriers on the cladding inner surface or by adding thermodynamically stable compound-forming elements to the fuel. Exploring this second option, in this work atomistic modeling with the Bozzolo-Ferrante-Smith (BFS) method for alloys is used to study the formation of lanthanide-rich precipitates in U-Zr fuel and the segregation patterns of all constituents to the surface. Surface energies for all elements were computed and, together with the underlying concepts of the computational methodology and large scale simulations, the migration of lanthanides to the surface region in U-Zr fuels is explained. The role of additions to the fuel such as In, Ga, and Tl for immobilization of lanthanides is discussed.

  19. Separation of actinides from lanthanides utilizing molten salt electrorefining

    SciTech Connect

    Grimmett, D.L.; Fusselman, S.P.; Roy, J.J.; Gay, R.L.; Krueger, C.L.; Storvick, T.S.; Inoue, T.; Hijikata, T.; Takahashi, N.

    1996-10-01

    TRUMP-S (TRansUranic Management through Pyropartitioning Separation) is a pyrochemical process being developed to separate actinides form fission products in nuclear waste. A key process step involving molten salt electrorefining to separate actinides from lanthanides has been studied on a laboratory scale. Electrorefining of U, Np, Pu, Am, and lanthanide mixtures from molten cadmium at 450 C to a solid cathode utilizing a molten chloride electrolyte resulted in > 99% removal of actinides from the molten cadmium and salt phases. Removal of the last few percent of actinides is accompanied by lowered cathodic current efficiency and some lanthanide codeposition. Actinide/lanthanide separation ratios on the cathode are ordered U > Np > Pu > Am and are consistent with predictions based on equilibrium potentials.

  20. Lanthanide ions as required cofactors for DNA catalysts.

    PubMed

    Dokukin, Victor; Silverman, Scott K

    2012-01-01

    We report that micromolar concentrations of lanthanide ions can be required cofactors for DNA-hydrolyzing deoxyribozymes. Previous work identified deoxyribozymes that simultaneously require both Zn(2+) and Mn(2+) to achieve DNA-catalyzed DNA hydrolysis (10(12) rate enhancement); a mutant of one such DNA catalyst requires only Zn(2+). Here we show that in vitro selection in the presence of 10 µM lanthanide ion (Ce(3+), Eu(3+), or Yb(3+)) along with 1 mM Zn(2+) leads to numerous DNA-hydrolyzing deoxyribozymes that strictly require the lanthanide ion as well as Zn(2+) for catalytic activity. These DNA catalysts have a range of lanthanide dependences, including some deoxyribozymes that strongly favor one particular lanthanide ion (e.g., Ce(3+) > Eu(3+) > Yb(3+)) and others that function well with more than one lanthanide ion. Intriguingly, two of the Yb(3+)-dependent deoxyribozymes function well with Yb(3+) alone (K(d,app) ~10 µM, in the absence of Zn(2+)) and have little or no activity with Eu(3+) or Ce(3+). In contrast to these selection outcomes when lanthanide ions were present, new selections with Zn(2+) or Mn(2+) alone, or Zn(2+) with Mg(2+)/Ca(2+), led primarily to deoxyribozymes that cleave DNA by deglycosylation and β-elimination rather than by hydrolysis, including several instances of depyrimidination. We conclude that lanthanide ions warrant closer attention as cofactors when identifying new nucleic acid catalysts, especially for applications in which high concentrations of polyvalent metal ion cofactors are undesirable.

  1. Lighting up cells with lanthanide self-assembled helicates

    PubMed Central

    Bünzli, Jean-Claude G.

    2013-01-01

    Lanthanide bioprobes and bioconjugates are ideal luminescent stains in view of their low propensity to photobleaching, sharp emission lines and long excited state lifetimes permitting time-resolved detection for enhanced sensitivity. We show here how the interplay between physical, chemical and biochemical properties allied to microfluidics engineering leads to self-assembled dinuclear lanthanide luminescent probes illuminating live cells and selectively detecting biomarkers expressed by cancerous human breast cells. PMID:24511387

  2. Syntheses, structures, and photoluminescence of three-dimensional lanthanide coordination polymers with 2,5-pyridinedicarboxylic acid

    SciTech Connect

    Huang Yan; Song Yishan; Yan, Bing Shao Min

    2008-08-15

    Four new open-framework coordination polymers of lanthanide 2,5-pyridinedicarboxylates, with the formulas Pr2(pydc){sub 3}(H{sub 2}O){sub 2} (1), Ln(pydc)(Hpydc) (Ln=Tb (2), Er (3), Eu (5)), and Gd(pydc)(nic)(H{sub 2}O) (4) (H{sub 2}pydc=2,5-pyridinedicarboxylic acid, Hnic=nicotinic acid), have been hydrothermally synthesized and four of them (except Eu (5)) have been structurally characterized. Complex 1 consists of two types of ligand-binding modes contributing to link the PrO{sub 7}N(H{sub 2}O) polyhedral chains to three-dimensional (3D) open-framework architecture. Complexes 2 and 3 are isostructural and feature unique 3D cage-like supramolecular frameworks remarkably different from that of 1, owing to the different ligand-bridging pattern. Complex 4, however, has the distinct 3D open-framework architecture due to the presence of unexpected nicotinate ligands, which may be derived from pydc ligands via in-situ decarboxylation under the hydrothermal condition. - Graphical abstract: Four new lanthanide coordination polymers have been hydrothermally synthesized by the reaction of 2,5-pyridinedicarboxylic acid with the corresponding lanthanide nitrates, and they show three types of 3D open-framework architecture. Complexes 2 and 5 show strong characteristic green (or red) luminescence and long lifetimes.

  3. The Effects of Trivalent Lanthanide Cationization on the Electron Transfer Dissociation of Acidic Fibrinopeptide B and its Analogs.

    PubMed

    Commodore, Juliette J; Cassady, Carolyn J

    2016-09-01

    Electrospray ionization (ESI) on mixtures of acidic fibrinopeptide B and two peptide analogs with trivalent lanthanide salts generates [M + Met + H](4+), [M + Met](3+), and [M + Met -H](2+), where M = peptide and Met = metal (except radioactive promethium). These ions undergo extensive and highly efficient electron transfer dissociation (ETD) to form metallated and non-metallated c- and z-ions. All metal adducted product ions contain at least two acidic sites, which suggest attachment of the lanthanide cation at the side chains of one or more acidic residues. The three peptides undergo similar fragmentation. ETD on [M + Met + H](4+) leads to cleavage at every residue; the presence of both a metal ion and an extra proton is very effective in promoting sequence-informative fragmentation. Backbone dissociation of [M + Met](3+) is also extensive, although cleavage does not always occur between adjacent glutamic acid residues. For [M + Met - H ](2+), a more limited range of product ions form. All lanthanide metal peptide complexes display similar fragmentation except for europium (Eu). ETD on [M + Eu - H](2+) and [M + Eu](3+) yields a limited amount of peptide backbone cleavage; however, [M + Eu + H](4+) dissociates extensively with cleavage at every residue. With the exception of the results for Eu(III), metallated peptide ion formation by ESI, ETD fragmentation efficiencies, and product ion formation are unaffected by the identity of the lanthanide cation. Adduction with trivalent lanthanide metal ions is a promising tool for sequence analysis of acidic peptides by ETD. Graphical Abstract ᅟ. PMID:27294379

  4. Periodic Trends in Lanthanide Compounds through the Eyes of Multireference ab Initio Theory.

    PubMed

    Aravena, Daniel; Atanasov, Mihail; Neese, Frank

    2016-05-01

    Regularities among electronic configurations for common oxidation states in lanthanide complexes and the low involvement of f orbitals in bonding result in the appearance of several periodic trends along the lanthanide series. These trends can be observed on relatively different properties, such as bonding distances or ionization potentials. Well-known concepts like the lanthanide contraction, the double-double (tetrad) effect, and the similar chemistry along the lanthanide series stem from these regularities. Periodic trends on structural and spectroscopic properties are examined through complete active space self-consistent field (CASSCF) followed by second-order N-electron valence perturbation theory (NEVPT2) including both scalar relativistic and spin-orbit coupling effects. Energies and wave functions from electronic structure calculations are further analyzed in terms of ab initio ligand field theory (AILFT), which allows one to rigorously extract angular overlap model ligand field, Racah, and spin-orbit coupling parameters directly from high-level ab initio calculations. We investigated the elpasolite Cs2NaLn(III)Cl6 (Ln(III) = Ce-Nd, Sm-Eu, Tb-Yb) crystals because these compounds have been synthesized for most Ln(III) ions. Cs2NaLn(III)Cl6 elpasolites have been also thoroughly characterized with respect to their spectroscopic properties, providing an exceptionally vast and systematic experimental database allowing one to analyze the periodic trends across the lanthanide series. Particular attention was devoted to the apparent discrepancy in metal-ligand covalency trends between theory and spectroscopy described in the literature. Consistent with earlier studies, natural population analysis indicates an increase in covalency along the series, while a decrease in both the nephelauxetic (Racah) and relativistic nephelauxetic (spin-orbit coupling) reduction with increasing atomic number is calculated. These apparently conflicting results are discussed on the

  5. Lanthanide structures, coordination, and extraction investigations of a 1,3-bis(diethyl amide)-substituted caliz[4]arene ligand

    SciTech Connect

    Beer, P.D.; Ogden, M.I.; Drew, M.G.B.

    1996-04-10

    The synthesis and structure determinations of lanthanum, samarium, ytterbium, and lutetium complexes of 5,11,17,23-tetra-tert-butyl-25,27-bis((diethylcarbamoyl)methoxy)-26,28-dihydroxycalix[4]arene (L) are described. The four structures display similar characteristics with the trivalent lanthanide cation being encapsulated in an eight-coordinate oxygen environment, consisting of six oxygens from the calixarene, a water molecule, and unidentate picrate for lanthanum [La(L-2H)(picrate)(H{sub 2}O)]; and bidentate chelating picrate for the other lanthanides [Ln(L-2H)(picrate)]Ln = Sm, Yb, Lu. Under optimised experimental conditions solvent extraction investigations showed the calix[4]arene ligand L exhibited generally very high percentage extractabilities of lanthanide cations into dichloromethane, presumably on account of the ligand`s unique lower rim oxygen containing coordination sphere and its lipophilic exterior.

  6. Lanthanide-Functionalized Hydrophilic Magnetic Hybrid Nanoparticles: Assembly, Magnetic Behaviour, and Photophysical Properties

    NASA Astrophysics Data System (ADS)

    Han, Shuai; Tang, Yu; Guo, Haijun; Qin, Shenjun; Wu, Jiang

    2016-05-01

    The lanthanide-functionalized multifunctional hybrid nanoparticles combining the superparamagnetic core and the luminescent europium complex were successfully designed and assembled via layer-by-layer strategy in this work. It is noted that the hybrid nanoparticles were modified by a hydrophilic polymer polyethyleneimine (PEI) through hydrogen bonding which bestowed excellent hydrophilicity and biocompatibility on this material. A bright-red luminescence was observed by fluorescence microscopy, revealing that these magnetic-luminescent nanoparticles were both colloidally and chemically stable in PBS solution. Therefore, the nanocomposite with magnetic resonance response and fluorescence probe property is considered to be of great potential in multi-modal bioimaging and diagnostic applications.

  7. Lanthanide-Functionalized Hydrophilic Magnetic Hybrid Nanoparticles: Assembly, Magnetic Behaviour, and Photophysical Properties.

    PubMed

    Han, Shuai; Tang, Yu; Guo, Haijun; Qin, Shenjun; Wu, Jiang

    2016-12-01

    The lanthanide-functionalized multifunctional hybrid nanoparticles combining the superparamagnetic core and the luminescent europium complex were successfully designed and assembled via layer-by-layer strategy in this work. It is noted that the hybrid nanoparticles were modified by a hydrophilic polymer polyethyleneimine (PEI) through hydrogen bonding which bestowed excellent hydrophilicity and biocompatibility on this material. A bright-red luminescence was observed by fluorescence microscopy, revealing that these magnetic-luminescent nanoparticles were both colloidally and chemically stable in PBS solution. Therefore, the nanocomposite with magnetic resonance response and fluorescence probe property is considered to be of great potential in multi-modal bioimaging and diagnostic applications. PMID:27245169

  8. Ytterbium(III) porpholactones: β-lactonization of porphyrin ligands enhances sensitization efficiency of lanthanide near-infrared luminescence.

    PubMed

    Ke, Xian-Sheng; Yang, Bo-Yan; Cheng, Xin; Chan, Sharon Lai-Fung; Zhang, Jun-Long

    2014-04-01

    The near-infrared (NIR) luminescence efficiency of lanthanide complexes is largely dependent on the electronic and photophysical properties of antenna ligands. Although porphyrin ligands are efficient sensitizers of lanthanide NIR luminescence, non-pyrrolic porphyrin analogues, which have unusual symmetry and electronic states, have been much less studied. In this work, we used porpholactones, a class of β-pyrrolic-modified porphyrins, as ligands and investigated the photophysical properties of lanthanide porpholactones Yb-1 a-5 a. Compared with Yb porphyrin complexes, the porpholactone complexes displayed remarkable enhancement of NIR emission (50-120 %). Estimating the triplet-state levels of porphyrin and porpholactone in Gd complexes revealed that β-lactonization of porphyrinic ligands lowers the ligand T1 state and results in a narrow energy gap between this state and the lowest excited state of Yb(3+) . Transient absorption spectra showed that Yb(III) porpholactone has a longer transient decay lifetime at the Soret band than the porphyrin analogue (30.8 versus 17.0 μs). Thus, the narrower energy gap and longer lifetime arising from β-lactonization are assumed to enhance NIR emission of Yb porpholactones. To demonstrate the potential applications of Yb porpholactone, a water-soluble Yb bioprobe was constructed by conjugating glucose to Yb-1 a. Interestingly, the NIR emission of this Yb porpholactone could be specifically switched on in the presence of glucose oxidase and then switched off by addition of glucose. This is the first demonstration that non-pyrrolic porphyrin ligands enhance the sensitization efficiency of lanthanide luminescence and also display switchable NIR emission in the region of biological analytes (800-1400 nm).

  9. Computer-Aided Molecular Design of Bis-phosphine Oxide Lanthanide Extractants

    DOE PAGES

    McCann, Billy W.; Silva, Nuwan De; Windus, Theresa L.; Gordon, Mark S.; Moyer, Bruce A.; Bryantsev, Vyacheslav S.; Hay, Benjamin P.

    2016-02-17

    Computer-aided molecular design and high-throughput screening of viable host architectures can significantly reduce the efforts in the design of novel ligands for efficient extraction of rare earth elements. This paper presents a computational approach to the deliberate design of bis-phosphine oxide host architectures that are structurally organized for complexation of trivalent lanthanides. Molecule building software, HostDesigner, was interfaced with molecular mechanics software, PCModel, providing a tool for generating and screening millions of potential R2(O)P-link-P(O)R2 ligand geometries. The molecular mechanics ranking of ligand structures is consistent with both the solution-phase free energies of complexation obtained with density functional theory and themore » performance of known bis-phosphine oxide extractants. For the case where link is -CH2-, evaluation of the ligand geometry provides the first characterization of a steric origin for the ‘anomalous aryl strengthening’ effect. The design approach has identified a number of novel bis-phosphine oxide ligands that are better organized for lanthanide complexation than previously studied examples.« less

  10. Computer-Aided Molecular Design of Bis-phosphine Oxide Lanthanide Extractants.

    PubMed

    McCann, Billy W; Silva, Nuwan De; Windus, Theresa L; Gordon, Mark S; Moyer, Bruce A; Bryantsev, Vyacheslav S; Hay, Benjamin P

    2016-06-20

    Computer-aided molecular design and high-throughput screening of viable host architectures can significantly reduce the efforts in the design of novel ligands for efficient extraction of rare earth elements. This paper presents a computational approach to the deliberate design of bis-phosphine oxide host architectures that are structurally organized for complexation of trivalent lanthanides. Molecule building software, HostDesigner, was interfaced with molecular mechanics software, PCModel, providing a tool for generating and screening millions of potential R2(O)P-link-P(O)R2 ligand geometries. The molecular mechanics ranking of ligand structures is consistent with both the solution-phase free energies of complexation obtained with density functional theory and the performance of known bis-phosphine oxide extractants. For the case where the link is -CH2-, evaluation of the ligand geometry provides the first characterization of a steric origin for the "anomalous aryl strengthening" effect. The design approach has identified a number of novel bis-phosphine oxide ligands that are better organized for lanthanide complexation than previously studied examples.

  11. Partitioning of lanthanides and Y between immiscible silicate and fluoride melts, fluorite and cryolite and the origin of the lanthanide tetrad effect in igneous rocks

    NASA Astrophysics Data System (ADS)

    Veksler, Ilya V.; Dorfman, Alexander M.; Kamenetsky, Maya; Dulski, Peter; Dingwell, Donald B.

    2005-06-01

    Some F-rich granitic rocks show anomalous, nonchondritic ratios of Y/Ho, extreme negative Eu anomalies, and unusual, discontinuous, segmented chondrite-normalised plots of rare earth elements (REE). The effects of F-rich fluids have been proposed as one of the explanations for the geochemical anomalies in the evolved granitic systems, as the stability of nonsilicate complexes of individual rare earths may affect the fluid-melt element partitioning. The lanthanide tetrad effect, related to different configurations of 4f-electron subshells of the lanthanide elements, is one of the factors affecting such complexing behaviour. We present the first experimental demonstration of the decoupling of Y and Ho, and the tetrad effect in the partitioning of rare earths between immiscible silicate and fluoride melts. Two types of experiments were performed: dry runs at atmospheric pressure in a high-temperature centrifuge at 1100 to 1200°C, and experiments with the addition of H 2O at 700 to 800°C and 100 MPa in rapid-quench cold-seal pressure vessels. Run products were analysed by electron microprobe (major components), solution-based inductively coupled plasma mass spectrometry (ICP-MS) (REE in the centrifuged runs), and laser ablation ICP-MS (REE and Li in the products of rapid-quench runs). All the dry centrifuge runs were performed at super-liquidus, two-phase conditions. In the experiments with water-bearing mixtures, minor amounts of aqueous vapour were present in addition to the melts. We found that lanthanides and Y concentrated strongly in the fluoride liquids, with two-melt partition coefficients reaching values as high as 100-220 in water-bearing compositions. In all the experimental samples, two-melt partition coefficients of lanthanides show subtle periodicity consistent with the tetrad effect, and the partition coefficient of Y is greater than that of Ho. One of the mixtures also produced abundant fluorite (CaF 2) and cryolite (Na 3AlF 6) crystals, which enabled

  12. Lanthanide accumulation in the periplasmic space of Escherichia coli B.

    PubMed

    Bayer, M E; Bayer, M H

    1991-01-01

    Treatment of growing Escherichia coli B with lanthanide ions [lanthanum(III), terbium(III), and europium(III)] and subsequent aldehyde-OsO4 fixation caused areas of high contrast to appear within the periplasm (the space between inner and outer membrane of the cell envelope). X-ray microanalysis of ultrathin sections of Epon-embedded or acrylic resin-embedded cells revealed the presence of the lanthanide and of phosphorus in the areas, whose contrast greatly exceeded that of other stained structures. Comparatively small amounts of the lanthanide were also present in the outer membrane and in the cytoplasm. The distribution of the periplasmic areas of high contrast was found to be random and not clustered at areas of current or future septum formation. Irregular cell shapes were observed after lanthanide treatment before onset of fixation. In contrast to glutaraldehyde-OsO4 fixation, glutaraldehyde used as the sole fixer caused a scattered distribution of the lanthanide. Cryofixation (slam-freezing) and freeze substitution revealed a lanthanum stain at both the periplasm and the outer part of the outer membrane. Deenergization of the cell membrane by either phage T4 or carbonyl cyanide m-chlorophenylhydrazone abolished the metal accumulation. Furthermore, addition of excess calcium, administered together with the lanthanide solution, diminished the quantity and size of areas of high contrast. Cells grown in media of high NaCl concentration revealed strongly stained areas of periplasmic precipitates, whereas cells grown under low-salt conditions showed very few high-contrast patches in the periplasm. Terbium treatment (during fixation) enhanced the visibility of the sites of inner-outer membrane contact (the membrane adhesion sites) in plasmolized cells, possibly as the result of an accumulation of the metal at the adhesion domains. The data suggest a rapid interaction of the lanthanides with components of the cell envelope, the periplasm, and the energized inner

  13. Lanthanide coordination polymers based on multi-donor ligand containing pyridine and phthalate moieties: Structures, luminescence and magnetic properties

    SciTech Connect

    Feng, Xun; Liu, Lang; Wang, Li-Ya; Song, Hong-Liang; Qiang Shi, Zhi; Wu, Xu-Hong; Ng, Seik-Weng

    2013-10-15

    A new family of five lanthanide-organic coordination polymers incorporating multi-functional N-hetrocyclic dicarboxylate ligand, namely, [Ln{sub 2}(Hdpp){sub 2}(dpp){sub 2}]{sub n}Ln=Pr(1), Eu(2), Gd(3), Dy(4), Er(5) (H{sub 2}dpp=1-(3, 4-dicarboxyphenyl) pyridin-4-ol) have been fabricated successfully through solvothermal reaction of 1-(3,4-dicarboxyphenyl)-4-hydroxypyridin-1-ium chloride with trivalent lanthanide salts, and have been characterized systematically. The complexes 1–5 are isomorphous and isostructural. They all feature three dimensional (3D) frameworks based on the interconnection of 1D double chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 4+} basic carboxylate as secondary building unit (SBU). The results of magnetic analysis shows the same bridging fashion of carboxylic group in this case results in the different magnetic properties occurring within lanthanide polymers. Moreover, the Eu(III) and Dy(III) complexes display characteristic luminescence emission in the visible regions. - Graphical abstract: A new family of lanthanide-organic frameworks incorporating multi-donor twisted ligand has been fabricated successfully, and has been characterized systematically. The complexes 1–5 are isostructural, and all feather three dimensional (3D) frameworks based on the interconnection of 1D double stride chains composed of the binuclear moiety [Ln{sub 2}(Hdpp){sub 2}]{sup 2+} basic carboxylate as secondary building unit (SBU). Display Omitted - Highlights: • New family of lanthanide–organic coordination polymers incorporating multifunctional N-hetrocyclic dicarboxylate ligand has been fabricated. • They have been characterized systematically. • They all feather three dimensional frameworks based on the binuclear moiety of [Ln{sub 2}(Hdpp){sub 2}]{sup 2+}. • The Eu(III) and Dy(III) analogues exhibit intense photoluminescence.

  14. A Simple Empirical Analysis of the Enthalpies of Formation of Lanthanide Halides and Oxides.

    ERIC Educational Resources Information Center

    Smith, Derek W.

    1986-01-01

    Proposes a simple and general method whereby the lattice energies of lanthanide(II) and (IV) compounds are derived directly from those found experimentally for the corresponding lanthanide(III) compounds. The method is applicable to all lanthanide halides and oxides and involves calculations which can be easily and quickly performed by students.…

  15. Lanthanide-doped hollow nanomaterials as theranostic agents.

    PubMed

    Kang, Xiaojiao; Li, Chunxia; Cheng, Ziyong; Ma, Ping'an; Hou, Zhiyao; Lin, Jun

    2014-01-01

    The field of theranostics has sprung up to achieve personalized medicine. The theranostics fuses diagnostic and therapeutic functions, empowering early diagnosis, targeted drug delivery, and real-time monitoring of treatment effect into one step. One particularly attractive class of nanomaterials for theranostic application is lanthanide-doped hollow nanomaterials (LDHNs). Because of the existence of lanthanide ions, LDHNs show outstanding fluorescent and paramagnetic properties, enabling them to be used as multimodal bioimaging agents. Synchronously, the huge interior cavities of LDHNs are able to be applied as efficacious tools for storage and delivery of therapeutic agents. The LDHNs can be divided into two types based on difference of component: single-phase lanthanide-doped hollow nanomaterials and lanthanide-doped hollow nanocomposites. We describe the synthesis of first kind of nanomaterials by use of hard template, soft template, template-free, and self-sacrificing template method. For lanthanide-doped hollow nanocomposites, we divide the preparation strategies into three kinds (one-step, two-step, and multistep method) according to the synthetic procedures. Furthermore, we also illustrate the potential bioapplications of these LDHNs, including biodetection, imaging (fluorescent imaging and magnetic resonance imaging), drug/gene delivery, and other therapeutic applications.

  16. Development of the Actinide-Lanthanide Separation (ALSEP) Process

    SciTech Connect

    Lumetta, Gregg J.; Carter, Jennifer C.; Niver, Cynthia M.; Gelis, Artem V.

    2014-09-30

    Separating the minor actinide elements (Am and Cm) from acidic high-level raffinates arising from the reprocessing of irradiated nuclear fuel is an important step in closing the nuclear fuel cycle. Most proposed approaches to this problem involve two solvent extraction steps: 1) co-extraction of the trivalent lanthanides and actinides, followed by 2) separation of the actinides from the lanthanides. The objective of our work is to develop a single solvent-extraction process for isolating the minor actinide elements. We report here a solvent containing N,N,N',N'-tetra(2 ethylhexyl)diglycolamide (T2EHDGA) combined with 2-ethylhexylphosphonic acid mono-2-ethylhexyl ester (HEH[EHP]) that can be used to separate the minor actinides in a single solvent-extraction process. T2EHDGA serves to co-extract the trivalent actinide and lanthanide ions from nitric acid solution. Switching the aqueous phase chemistry to a citrate buffered solution of N-(2-hydroxyethyl)ethylenediamine-N,N',N'-triacetic acid at pH 2.5 to 4 results in selective transfer of the actinides to the aqueous phase, thus affecting separation of the actinides from the lanthanides. Separation factors between the lanthanides and actinides are approximately 20 in the pH range of 3 to 4, and the distribution ratios are not highly dependent on the pH in this system.

  17. Multi-component lanthanide hybrids based on zeolite A/L and zeolite A/L-polymers for tunable luminescence.

    PubMed

    Chen, Lei; Yan, Bing

    2015-02-01

    Some multi-component hybrids based on zeolite L/A are prepared. Firstly, zeolite A/L is loaded with lanthanide complexes (Eu-DBM or Tb-AA (acetylacetone = AA, dibenzoylmethane = DBM)) into its channels. Secondly, 3-methacryloyloxypropyltrimethoxysilane (γ-MPS) is used to covalently graft onto the surface of functionalized zeolite A/L (Si-[ZA/L⊃Eu-DBM(Tb-AA)]). Thirdly, lanthanide ions (Eu(3+)/Tb(3+)) are coordinated to the functionalized zeolite A/L and ligands (phen(1,10-phenanthroline) or bipy (2,2'-bipyridyl)) are introduced by a ship-in-bottle method. The inside-outside double modifications of ZA/L with lanthanide complexes afford the final hybrids and these are characterized by means of XRD, FT-IR, UV-vis DRS, SEM and luminescence spectroscopy, some of which display white or near-white light emission. Furthermore, selected above-mentioned hybrids are incorporated into PEMA/PMMA (poly ethyl methylacryate/poly methyl methacrylate) hosts to prepare luminescent polymer films. These results provide abundant data that these hybrid materials can be expected to have potential application in various practical fields.

  18. Allosteric effects in binuclear homo- and heterometallic triple-stranded lanthanide podates.

    PubMed

    Ryan, Patrick E; Canard, Gabriel; Koeller, Sylvain; Bocquet, Bernard; Piguet, Claude

    2012-09-17

    This work illustrates a simple approach for deciphering and exploiting the various free energy contributions to the global complexation process leading to the binuclear triple-stranded podates [Ln(2)(L9)](6+) (Ln is a trivalent lanthanide). Despite the larger microscopic affinities exhibited by the binding sites for small Ln(3+), the stability constants measured for [Ln(2)(L9)](6+) decrease along the lanthanide series; a phenomenon which can be ascribed to the severe enthalpic penalty accompanying the intramolecular cyclization around small Ln(III), combined with increasing anticooperative allosteric interligand interactions. Altogether, the microscopic thermodynamic characteristics predict β(1,1,1)(La,Lu,L9)/β(1,1,1)(Lu,La,L9) = 145 for the ratio of the formation constants of the target heterobimetallic [LaLu(L9)](6+) and [LuLa(L9)](6+) microspecies, a value in line with the quantitative preparation (>90%) of [LaLu(L9)](6+) at millimolar concentrations. Preliminary NMR titrations indeed confirm the rare thermodynamic programming of a pure heterometallic f-f' complex. PMID:22946598

  19. Lanthanide triple-stranded helicates: controlling the yield of the heterobimetallic species.

    PubMed

    Jensen, Thomas B; Scopelliti, Rosario; Bünzli, Jean-Claude G

    2006-09-18

    Two unsymmetrical ditopic hexadentate ligands designed for the simultaneous recognition of two different trivalent lanthanide ions have been synthesized, L(AB2) and L(AB3), where A represents a tridentate benzimidazole-pyridine-benzimidazole coordination unit, B2 a diethylamine-substituted benzimidazole-pyridine-carboxamide one, and B3 a chlorine-substituted benzimidazole-pyridine-carboxamide moiety. Under stoichiometric 2:3 (Ln/L) conditions, these ligands self-assemble with lanthanide ions to yield triple-stranded bimetallic helicates. The crystal structures of four helicates with L(AB3) of composition [LnLn'(L(AB3))3](ClO4)6.solv (CeCe, PrPr, PrLu, NdLu) show the metal ions embedded into a helical structure with a pitch of about 13.2-13.4 A. The metal ions lie at a distance of 9.1-9.2 A and are nine-coordinated by the three ligand strands, which are oriented in a HHH (head-head-head) fashion, where all ligand strands are oriented in the same direction. In the presence of a pair of different lanthanide ions in acetonitrile solution, the ligand L(AB3) shows selectivity and gives high yields of heterobimetallic complexes. L(AB2) displays less selectivity, and this is shown to be directly related to the tendency of this ligand to form high yields of HHT (head-head-tail) isomer. A fine-tuning of the HHH left arrow over right arrow HHT equilibrium and of the selectivity for heteropairs of Ln(III) ions is therefore at hand. PMID:16961372

  20. Mixed lanthanide oxide nanoparticles as dual imaging agent in biomedicine

    NASA Astrophysics Data System (ADS)

    Xu, Wenlong; Bony, Badrul Alam; Kim, Cho Rong; Baeck, Jong Su; Chang, Yongmin; Bae, Ji Eun; Chae, Kwon Seok; Kim, Tae Jeong; Lee, Gang Ho

    2013-11-01

    There is no doubt that the molecular imaging is an extremely important technique in diagnosing diseases. Dual imaging is emerging as a step forward in molecular imaging technique because it can provide us with more information useful for diagnosing diseases than single imaging. Therefore, diverse dual imaging modalities should be developed. Molecular imaging generally relies on imaging agents. Mixed lanthanide oxide nanoparticles could be valuable materials for dual magnetic resonance imaging (MRI)-fluorescent imaging (FI) because they have both excellent and diverse magnetic and fluorescent properties useful for dual MRI-FI, depending on lanthanide ions used. Since they are mixed nanoparticles, they are compact, robust, and stable, which is extremely useful for biomedical applications. They can be also easily synthesized with facile composition control. In this study, we explored three systems of ultrasmall mixed lanthanide (Dy/Eu, Ho/Eu, and Ho/Tb) oxide nanoparticles to demonstrate their usefulness as dual T2 MRI-FI agents.

  1. Ultrasensitive DNAzyme beacon for lanthanides and metal speciation.

    PubMed

    Huang, Po-Jung Jimmy; Lin, Jenny; Cao, Jing; Vazin, Mahsa; Liu, Juewen

    2014-02-01

    Metal-ion detection and speciation analysis is crucial for environmental monitoring. Despite the importance of lanthanides, few sensors are available for their detection. DNAzymes have been previously used to detect divalent metals, while no analytical work was carried out for trivalent and tetravalent ions. Herein, in vitro selection was performed using a Ce(4+) salt as the target metal, and a new DNAzyme (named Ce13) with a bulged hairpin structure was isolated and characterized. Interestingly, Ce13 has almost no activity with Ce(4+) but is highly active with all trivalent lanthanides and Y(3+), serving as a general probe for rare earth metals (omitting Sc). A DNAzyme beacon was engineered detecting down to 1.7 nM Ce(3+) (240 parts per trillion), and other lanthanides showed similar sensitivity. The feasibility of metal speciation analysis was demonstrated by measuring the reduction of Ce(4+) to Ce(3+).

  2. Spectroscopic studies on the lanthanide sensitized luminescence and chemiluminescence properties of fluoroquinolone with different structure

    NASA Astrophysics Data System (ADS)

    Sun, Chunyan; Ping, Hong; Zhang, Minwei; Li, Hongkun; Guan, Fengrui

    2011-11-01

    Lanthanide sensitized luminescence and chemiluminescence (CL) are of great importance because of the unique spectral properties, such as long lifetime, large Stokes shifts, and narrow emission bands characteristic to lanthanide ions (Ln 3+). With the fluoroquinolone (FQ) compounds including enoxacin (ENX), norfloxacin (NFLX), lomefloxacin (LMFX), fleroxacin (FLRX), ofloxacin (OFLX), rufloxacin (RFX), gatifloxacin (GFLX) and sparfloxacin (SPFX), the luminescence and CL properties of Tb 3+-FQ and Eu 3+-FQ complexes have been investigated in this contribution. Ce 4+-SO 32- in acidic conditions was taken as the CL system and sensitized CL intensities of Tb 3+-FQ and Eu 3+-FQ complexes were determined by flow-injection analysis. The luminescence and CL spectra of Tb 3+-FQ complexes show characteristic peaks of Tb 3+ at 490 nm, 545 nm, 585 nm and 620 nm. Complexes of Tb 3+-ENX, Tb 3+-NFLX, Tb 3+-LMFX and Tb 3+-FLRX display relatively strong emission intensity compared with Tb 3+-OFLX, Tb 3+-RFX, Tb 3+-GFLX and Tb 3+-SPFX. Quite weak peaks with unique characters of Eu 3+ at 590 nm and 617 nm appear in the luminescence and CL spectra of Eu 3+-ENX, but no notable sensitized luminescence and CL of Eu 3+ could be observed when Eu 3+ is added into other FQ. The distinct differences on emission intensity of Tb 3+-FQ and Eu 3+-FQ might originate from the different energy gap between the triplet levels of FQ and the excited levels of the Ln 3+. The different sensitized luminescence and CL signals among Tb 3+-FQ complexes could be attributed to different optical properties and substituents of these FQ compounds. The detailed mechanism involved in the luminescence and CL properties of Tb 3+-FQ and Eu 3+-FQ complexes has been investigated by analyzing the luminescence and CL spectra, quantum yields, and theoretical calculation results.

  3. Preparation and study of an f,f,f',f'' covalently linked tetranuclear hetero-trimetallic complex - a europium, terbium, dysprosium triad.

    PubMed

    Sørensen, Thomas Just; Tropiano, Manuel; Blackburn, Octavia A; Tilney, James A; Kenwright, Alan M; Faulkner, Stephen

    2013-01-28

    A heterotrimetallic tetranuclear lanthanide complex containing two dysprosium ions, a terbium ion and a europium ion has been prepared by coupling three kinetically stable complexes together using the Ugi reaction. The covalently linked trimetallic system exhibits luminescence from all the different lanthanide centres.

  4. Method for providing oxygen ion vacancies in lanthanide oxides

    DOEpatents

    Kay, D. Alan R.; Wilson, William G.

    1989-12-05

    A method for desulfurization of fuel gases resulting from the incomplete combustion of sulfur containing hydrocarbons whereby the gases are treated with lanthanide oxides containing large numbers of oxygen-ion vacancies providing ionic porosity which enhances the ability of the lanthanide oxides to react more rapidly and completely with the sulfur in the fuel gases whereby the sulfur in such gases is reduced to low levels suitable for fuels for firing into boilers of power plants generating electricity with steam turbine driven generators, gas turbines, fuel cells and precursors for liquid fuels such as methanol and the like.

  5. Plasma mass filtering for separation of actinides from lanthanides

    NASA Astrophysics Data System (ADS)

    Gueroult, R.; Fisch, N. J.

    2014-06-01

    Separating lanthanides from actinides is a key process in reprocessing nuclear spent fuel. Plasma mass filters, which operate on dissociated elements, offer conceptual advantages for such a task as compared with conventional chemical methods. The capabilities of a specific plasma mass filter concept, called the magnetic centrifugal mass filter, are analyzed within this particular context. Numerical simulations indicate separation of americium ions from a mixture of lanthanides ions for plasma densities of the order of 1012 cm-3, and ion temperatures of about 10 eV. In light of collision considerations, separating small fractions of heavy elements from a larger volume of lighter ones is shown to enhance the separation capabilities.

  6. Method for extracting lanthanides and actinides from acid solutions

    DOEpatents

    Horwitz, E. Philip; Kalina, Dale G.; Kaplan, Louis; Mason, George W.

    1985-01-01

    A process for the recovery of actinide and lanthanide values from aqueous acidic solutions with an organic extractant having the formula: ##STR1## where .phi. is phenyl, R.sup.1 is a straight or branched alkyl or alkoxyalkyl containing from 6 to 12 carbon atoms and R.sup.2 is an alkyl containing from 3 to 6 carbon atoms. The process is suitable for the separation of actinide and lanthanide values from fission product values found together in high level nuclear reprocessing waste solutions.

  7. SOLVENT EXTRACTION PROCESS FOR SEPARATING ACTINIDE AND LANTHANIDE METAL VALUES

    DOEpatents

    Hildebrandt, R.A.; Hyman, H.H.; Vogler, S.

    1962-08-14

    A process of countercurrently extracting an aqueous mineral acid feed solution for the separation of actinides from lanthanides dissolved therern is described. The feed solution is made acid-defrcient with alkali metal hydroxide prior to.contact with acid extractant; during extraction, however, acid is transferred from organic to aqueous solution and the aqueous solution gradually becomes acid. The acid-deficient phase ' of the process promotes the extraction of the actinides, while the latter acid phase'' of the process improves retention of the lanthanides in the aqueous solution. This provides for an improved separation. (AEC)

  8. Thermodynamical properties of liquid lanthanides-A variational approach

    SciTech Connect

    Patel, H. P.; Thakor, P. B.; Sonvane, Y. A.

    2015-06-24

    Thermodynamical properties like Entropy (S), Internal energy (E) and Helmholtz free energy (F) of liquid lanthanides using a variation principle based on the Gibbs-Bogoliubuv (GB) inequality with Percus Yevick hard sphere reference system have been reported in the present investigation. To describe electron-ion interaction we have used our newly constructed parameter free model potential along with Sarkar et al. local field correction function. Lastly, we conclude that our newly constructed model potential is capable to explain the thermodynamical properties of liquid lanthanides.

  9. Property enchancement of polyimide films by way of the incorporation of lanthanide metal ions

    NASA Technical Reports Server (NTRS)

    Thompson, David W.

    1993-01-01

    Lanthanide metal ions were incorporated into the polyimide derived from 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) and 1,3-bis(aminophenoxy) benzene (APB) in an attempt to produce molecular level metal-polymer composites. The lanthanide series of metal ions (including aluminum, scandium, and yttrium) provide discrete and stable metal ions in the 3+ oxidation state. Throughout the series there is a uniform variation in ionic size ranging from 50 pm for aluminum to a maximum of 103.4 pm for cerium and gradually decreasing again to 84.8 pm for lutetium. The high charge-to-size ratio for these ions as well as the ability to obtain large coordination numbers makes them excellent candidates for interacting with the polymer substructure. The distinct lack of solubility of simple lanthanide salts such as the acetates and halides has made it difficult to obtain metal ions distributed in the polymer framework as discrete ions or metal complexes rather than microcomposites of metal clusters. (Lanthanum nitrates are quite soluble, but the presence of the strongly oxidizing nitrate ion leads to serious degradation of the polymer upon thermal curing. This work was successful at extending the range of soluble metals salts by using chelating agents derived from the beta-diketones dipivaloylmethane, dibenzoylmethane, trifluoroacetylacetone, and hexafluoroacetylacetone. Metal acetates which are insoluble in dimethylacetamide dissolve readily in the presence of the diketones. Addition of the polyimide yields a homogeneous resin which is then cast into a clear film. Upon curing clear films were obtained with the dibenzoylmethane and trifluoroacetylacetone ligands. The dipavaloylmethane precipitates the metal during the film casting process, and hexafluoroacetylacetone gives cured films which are deformed and brittle. These clear films are being evaluated for the effect of the metal ions on the coefficient of thermal expansion, resistance to atomic oxygen, and on

  10. Supramolecular recognition of heteropairs of lanthanide ions: a step toward self-assembled bifunctional probes.

    PubMed

    André, Nicolas; Jensen, Thomas B; Scopelliti, Rosario; Imbert, Daniel; Elhabiri, Mourad; Hopfgartner, Gérard; Piguet, Claude; Bünzli, Jean-Claude G

    2004-01-26

    Three unsymmetrical ditopic hexadentate ligands coded for the recognition of trivalent lanthanide ions have been synthesized, L(AB), L(AC), and L(BC), where A represents a benzimidazole-pyridine-benzimidazole coordination unit, B a benzimidazole-pyridine-carboxamide one, and C a benzimidazole-pyridine-carboxylic acid moiety. Under stoichiometric 2:3 (Ln:L) conditions, these ligands self-assemble with lanthanide ions to yield triple-stranded bimetallic helicates having a sizable stability in acetonitrile: log beta(23) values for Eu are equal to 23.9 +/- 0.5 (L(AB)), 23.3 +/- 0.7 (deprotonated L(AC)), and 29.8 +/- 0.5 (deprotonated L(BC)). The crystal structure of the EuEu helicate with L(AB) shows 9-coordinate metal ions and an HHH (H stands for head) configuration of the helically wrapped ligand strands. In the presence of equimolar quantities of Ln and Ln' ions, L(AB) displays a remarkable predisposition to form HHH-heterobimetallic edifices, as proved both in the solid state by the crystal structures of the LaEu, LaTb, PrEr, and PrLu helicates and in solution by NMR spectroscopy. In all cases, the benzimidazole-pyridine-carboxamide units of the three ligands are bound to the smaller lanthanide ion, a fact further ascertained by high-resolution luminescence data on LaEu and by (1)H NMR. Analysis of the lanthanide-induced (1)H NMR shifts and of the spin-lattice relaxation times of the [LnLu(L(AB))(3)](6+) series (Ln = Ce, Pr, Nd, Sm, Eu) demonstrates the isostructural nature of the complexes in solution and that the crystal structure of LaTb is a good model for the solution structure. The selectivity of L(AB) for heteropairs of Ln(III) ions increases with increasing difference in ionic radius, resulting in 70% of the heterobimetallic species for deltar(i) = 0.1 A and up to 90% for LaLu (deltar(i) = 0.18 A), and corresponding to delta(deltaG) in the range 3-10 kJ.mol(-)(1). The origins of this stabilization are discussed in terms of the donor properties of the

  11. Advanced Extraction Methods for Actinide/Lanthanide Separations

    SciTech Connect

    Scott, M.J.

    2005-12-01

    The separation of An(III) ions from chemically similar Ln(III) ions is perhaps one of the most difficult problems encountered during the processing of nuclear waste. In the 3+ oxidation states, the metal ions have an identical charge and roughly the same ionic radius. They differ strictly in the relative energies of their f- and d-orbitals, and to separate these metal ions, ligands will need to be developed that take advantage of this small but important distinction. The extraction of uranium and plutonium from nitric acid solution can be performed quantitatively by the extraction with the TBP (tributyl phosphate). Commercially, this process has found wide use in the PUREX (plutonium uranium extraction) reprocessing method. The TRUEX (transuranium extraction) process is further used to coextract the trivalent lanthanides and actinides ions from HLLW generated during PUREX extraction. This method uses CMPO [(N, N-diisobutylcarbamoylmethyl) octylphenylphosphineoxide] intermixed with TBP as a synergistic agent. However, the final separation of trivalent actinides from trivalent lanthanides still remains a challenging task. In TRUEX nitric acid solution, the Am(III) ion is coordinated by three CMPO molecules and three nitrate anions. Taking inspiration from this data and previous work with calix[4]arene systems, researchers on this project have developed a C3-symmetric tris-CMPO ligand system using a triphenoxymethane platform as a base. The triphenoxymethane ligand systems have many advantages for the preparation of complex ligand systems. The compounds are very easy to prepare. The steric and solubility properties can be tuned through an extreme range by the inclusion of different alkoxy and alkyl groups such as methyoxy, ethoxy, t-butoxy, methyl, octyl, t-pentyl, or even t-pentyl at the ortho- and para-positions of the aryl rings. The triphenoxymethane ligand system shows promise as an improved extractant for both tetravalent and trivalent actinide recoveries form

  12. Breaking and Making of Carbon-Carbon Bonds by Lanthanides and Third-Row Transition Metals.

    PubMed

    Zhou, Shaodong; Li, Jilai; Schlangen, Maria; Schwarz, Helmut

    2016-02-24

    Carbon-atom extrusion from the ipso-position of a halobenzene ring (C6 H5 X; X=F, Cl, Br, I) and its coupling with a methylene ligand to produce acetylene is not confined to [LaCH2 ](+) ; also, the third-row transition-metal complexes [MCH2 ](+) , M=Hf, Ta, W, Re, and Os, bring about this unusual transformation. However, substrates with substituents X=CN, NO2 , OCH3 , and CF3 are either not reactive at all or give rise to different products when reacted with [LaCH2 ](+) . In the thermal gas-phase processes of atomic Ln(+) with C7 H7 Cl substrates, only those lanthanides with a promotion energy small enough to attain a 4f(n) 5d(1) 6s(1) configuration are reactive and form both [LnCl](+) and [LnC5 H5 Cl](+) . Branching ratios and the reaction efficiencies of the various processes seem to correlate with molecular properties, like the bond-dissociation energies of the C-X or M(+) -X bonds or the promotion energies of lanthanides. PMID:26875940

  13. Advancing Chemistry with the Lanthanide and Actinide Elements Final Report, September 2013

    SciTech Connect

    Evans, William John

    2013-09-11

    The objective of this research is to use the unique chemistry available from complexes of the lanthanides and actinides, as well as related heavy metals such as scandium, yttrium, and bismuth to advance chemistry in energy-related areas. The lanthanides and actinides have a combination of properties in terms of size, charge, electropositive character, and f valence orbitals that provides special opportunities to probe reactivity and catalysis in ways not possible with the other metals in the periodic table. We seek to discover reaction pathways and structural types that reveal new options in reaction chemistry related to energy. Identification of new paradigms in structure and reactivity should stimulate efforts to develop new types of catalytic processes that at present are not under consideration because either the transformation or the necessary intermediates are unknown. This project is one half of my laboratory’s DOE research which was split 50:50 between Catalysis and Heavy Element Chemistry programs in 2010. Hence, this report is for a half-project.

  14. Tailoring Bicelle Morphology and Thermal Stability with Lanthanide-Chelating Cholesterol Conjugates.

    PubMed

    Isabettini, Stéphane; Liebi, Marianne; Kohlbrecher, Joachim; Ishikawa, Takashi; Windhab, Erich J; Fischer, Peter; Walde, Peter; Kuster, Simon

    2016-09-01

    Bicelles composed of DMPC and phospholipids capable of chelating lanthanide ions, such as 1,2-dimyristoyl-sn-glycero-3-phospho-ethanolamine-diethylene triaminepentaacetate (DMPE-DTPA), are highly tunable magnetically responsive soft materials. Further doping of these systems with cholesterol-DTPA conjugates complexed to a lanthanide ion considerably enhances the bicelle's size and magnetic alignability. The high value of these cholesterol conjugates for bicelle design remains largely unexplored. Herein, we examine how molecular structural alterations within the cholesterol-DTPA conjugates lead to contrasting self-assembled polymolecular aggregate structures when incorporated into DMPC/DMPE-DTPA/Tm(3+) bilayers. The nature of the linker connecting the DTPA-chelating moiety to the sterol backbone is examined by synthesizing conjugates of various linker lengths and polarities. The incorporation of these compounds within the bilayer results in polymolecular aggregate geometries of higher curvature. The increasing degrees of freedom for conformational changes conveyed to the chelator headgroup with increasing linker atomic length reduce the cholesterol-DTPA conjugate's critical packing parameter. Consequently, an inverse correlation between the number of carbon atoms in the linker and the bicelle radius is established. The introduction of polarity into the carbon chain of the linker did not cause major changes in the polymolecular aggregate architecture. Under specific conditions, the additives permit the formation of remarkably temperature-resistant bicelles. The versatility of design offered by these amphiphiles gives rise to new and viable tools for the growing field of magnetically responsive soft materials. PMID:27529644

  15. Synthesis and Characterization of Europium(III) and Terbium(III) Complexes: An Advanced Undergraduate Inorganic Chemistry Experiment

    ERIC Educational Resources Information Center

    Swavey, Shawn

    2010-01-01

    Undergraduate laboratories rarely involve lanthanide coordination chemistry. This is unfortunate in light of the ease with which many of these complexes are made and the interesting and instructive photophysical properties they entail. The forbidden nature of the 4f transitions associated with the lanthanides is overcome by incorporation of…

  16. Interactions between metal ions and carbohydrates. Spectroscopic characterization and the topology coordination behavior of erythritol with trivalent lanthanide ions.

    PubMed

    Yang, Limin; Hua, Xiaohui; Xue, Junhui; Pan, Qinghua; Yu, Lei; Li, Weihong; Xu, Yizhuang; Zhao, Guozhong; Liu, Liming; Liu, Kexin; Chen, Jia'er; Wu, Jinguang

    2012-01-01

    The coordination of carbohydrate to metal ions is important because it may be involved in many biochemical processes. The synthesis and characterization of several novel lanthanide-erythritol complexes (TbCl(3)·1.5C(4)H(10)O(4)·H(2)O (TbE(I)), Pr(NO(3))(3)·C(4)H(10)O(4)·2H(2)O (PrEN), Ce(NO(3))(3)·C(4)H(10)O(4)·2H(2)O (CeEN), Y(NO(3))(3)·C(4)H(10)O(4)·C(2)H(5)OH (YEN), Gd(NO(3))(3)·C(4)H(10)O(4)·C(2)H(5)OH (GdEN)) and Tb(NO(3))(3)·C(4)H(10)O(4)·C(2)H(5)OH (TbEN) are reported. The structures of these complexes in the solid state have been determined by X-ray diffraction. Erythritol is used as two bidentate ligands or as three hydroxyl group donor in these complexes. FTIR spectra indicate that two kinds of structures, with water and without water involved in the coordination sphere, were observed for lanthanide nitrate-erythritol complexes. FIR and THz spectra show the formation of metal ion-erythritol complexes. Luminescence spectra of Tb-erythritol complexes have the characteristics of the Tb ion.

  17. Luminescent Lanthanide Reporters for High-Sensitivity Novel Bioassays.

    SciTech Connect

    Anstey, Mitchell R.; Fruetel, Julia A.; Foster, Michael E.; Hayden, Carl C.; Buckley, Heather L.; Arnold, John

    2013-09-01

    Biological imaging and assay technologies rely on fluorescent organic dyes as reporters for a number of interesting targets and processes. However, limitations of organic dyes such as small Stokes shifts, spectral overlap of emission signals with native biological fluorescence background, and photobleaching have all inhibited the development of highly sensitive assays. To overcome the limitations of organic dyes for bioassays, we propose to develop lanthanide-based luminescent dyes and demonstrate them for molecular reporting applications. This relatively new family of dyes was selected for their attractive spectral and chemical properties. Luminescence is imparted by the lanthanide atom and allows for relatively simple chemical structures that can be tailored to the application. The photophysical properties offer unique features such as narrow and non-overlapping emission bands, long luminescent lifetimes, and long wavelength emission, which enable significant sensitivity improvements over organic dyes through spectral and temporal gating of the luminescent signal.Growth in this field has been hindered due to the necessary advanced synthetic chemistry techniques and access to experts in biological assay development. Our strategy for the development of a new lanthanide-based fluorescent reporter system is based on chelation of the lanthanide metal center using absorbing chromophores. Our first strategy involves "Click" chemistry to develop 3-fold symmetric chelators and the other involves use of a new class of tetrapyrrole ligands called corroles. This two-pronged approach is geared towards the optimization of chromophores to enhance light output.

  18. On the Suitability of Lanthanides as Actinide Analogs

    SciTech Connect

    Szigethy, Geza; Raymond, Kenneth N.

    2008-04-11

    With the current level of actinide materials used in civilian power generation and the need for safe and efficient methods for the chemical separation of these species from their daughter products and for long-term storage requirements, a detailed understanding of actinide chemistry is of great importance. Due to the unique bonding properties of the f-elements, the lanthanides are commonly used as structural and chemical models for the actinides, but differences in the bonding between these 4f and 5f elements has become a question of immediate applicability to separations technology. This brief overview of actinide coordination chemistry in the Raymond group at UC Berkeley/LBNL examines the validity of using lanthanide analogs as structural models for the actinides, with particular attention paid to single crystal X-ray diffraction structures. Although lanthanides are commonly accepted as reasonable analogs for the actinides, these comparisons suggest the careful study of actinide materials independent of their lanthanide analogs to be of utmost importance to present and future efforts in nuclear industries.

  19. Heat capacities of lanthanide and actinide monazite-type ceramics

    NASA Astrophysics Data System (ADS)

    Kowalski, Piotr M.; Beridze, George; Vinograd, Victor L.; Bosbach, Dirk

    2015-09-01

    (Ln, An)xPO4 monazite-type ceramics are considered as potential matrices for the disposal of nuclear waste. In this study we computed the heat capacities and the standard entropies of these compounds using density functional perturbation theory. The calculations of lanthanide monazites agree well with the existing experimental data and provide information on the variation of the standard heat capacities and entropies along the lanthanide series. The results for AnPO4 monazites are similar to those obtained for the isoelectronic lanthanide compounds. This suggests that the missing thermodynamic data on actinide monazites could be similarly computed or assessed based on the properties of their lanthanide analogs. However, the computed heat capacity of PuPO4 appear to be significantly lower than the measured data. We argue that this discrepancy might indicate potential problems with the existing experimental data or with their interpretation. This shows a need for further experimental studies of the heat capacities of actinide-bearing, monazite-type ceramics.

  20. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    SciTech Connect

    Lippuner, Jonas; Roberts, Luke F.

    2015-12-20

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y{sub e}, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y{sub e} ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y{sub e} lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y{sub e}, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y{sub e}, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

  1. Lanthanide sorption on smectitic clays in presence of cement leachates

    NASA Astrophysics Data System (ADS)

    Galunin, Evgeny; Alba, María D.; Santos, Maria J.; Abrão, Taufik; Vidal, Miquel

    2010-02-01

    Due to their potential retention capacity, clay minerals have been proposed for use in the engineered barriers for the storage of high-level radioactive actinides in deep geological waste repositories. However, there is still a lack of data on the sorption of actinides in clays in conditions simulating those of the repositories. The present article examines the sorption of two lanthanides (actinide analogues) in a set of smectitic clays (FEBEX bentonite, MX80 bentonite, hectorite, saponite, Otay montmorillonite, and Texas montmorillonite). Distribution coefficients ( Kd) were determined in two media: water and 0.02 mol L -1 Ca, the latter representing the cement leachates that may modify the chemical composition of the water in contact with the clay. The Kd values of the lanthanides used in the experiments (La and Lu) varied greatly (25-50 000 L kg -1) depending on the ionic medium (higher values in water than in the Ca medium), the initial lanthanide concentration (up to three orders of magnitude decrease inversely with lanthanide concentration), and the examined clay (up to one order of magnitude for the same lanthanide and sorption medium). Freundlich and Langmuir isotherms were used to fit sorption data to allow comparison of the sorption parameters among smectites. The model based on the two-site Langmuir isotherms provided the best fit of the sorption data, confirming the existence of sorption sites with different binding energies. The sites with higher sorption affinity were about 6% of the total sorption capacity in the water medium, and up to 17% in the Ca medium, although in this latter site sorption selectivity was lower. The wide range of Kd values obtained regarding the factors examined indicated that the retention properties of the clays should also be considered when selecting a suitable clay for engineered barriers.

  2. Bispyrene/surfactant-assembly-based fluorescent sensor array for discriminating lanthanide ions in aqueous solution.

    PubMed

    Wang, Shihuai; Ding, Liping; Fan, Junmei; Wang, Zhongxiu; Fang, Yu

    2014-09-24

    Lanthanides are valuable nonrenewable resources and widely used in a variety of industries. Detection and identification of lanthanide ions are in high demand but challenging because of the similarity among lanthanide ions. In the present work, a fluorescent sensor array of three cationic bispyrene derivatives mixed with anionic surfactant assemblies was developed. The sensor array exhibits cross-reactive responses to lanthanide ions when tested in aqueous solution. The combination of fluorescence variations at both monomer and excimer emission of each of the bispyrene sensor elements provides a six-signal recognition pattern for lanthanide ions. Principle component analysis illustrates that the sensor array could at least identify 6 of the 14 similar lanthanide ions including La(3+), Pr(3+), Nd(3+), Eu(3+), Ho(3+), and Er(3+). UV-vis absorption measurements rule out the possibility of binding lanthanides with fluorophores. Fluorescence titration experiments in both cationic and neutral surfactant aqueous solutions reveal that the three fluorophores show slight fluorescence responses to the lanthanide ions, indicating that electrostatic attraction between lanthanide ions and anionic surfactant plays an important role in the sensing behavior of the sensor array. Control experiments with divalent metal ions find no cross-reactive responses, suggesting that the stronger electrostatic interaction with trivalent lanthanide ions is responsible for the multiple fluorescence responses. PMID:25188720

  3. Feasibility of the electrochemical way in molten fluorides for separating thorium and lanthanides and extracting lanthanides from the solvent

    NASA Astrophysics Data System (ADS)

    Chamelot, P.; Massot, L.; Hamel, C.; Nourry, C.; Taxil, P.

    2007-01-01

    An alternative way of reprocessing nuclear fuel by hydrometallurgy could be using treatment with molten salts, particularly fluoride melts. Moreover, one of the six concepts chosen for GEN IV nuclear reactors (Technology Roadmap - http://gif.inel.gov/roadmap/) is the molten salt reactor (MSR). The originality of the concept is the use of molten salts as liquid fuel and coolant. During the running of the reactor, fission products, particularly lanthanides, accumulate in the melt and have to be eliminated to optimise reactor operation. This study concerns the feasibility of the separation actinides-lanthanides-solvent by selectively electrodepositing the elements to be separated on an inert (Mo, Ta) or a reactive (Ni) cathodic substrate in molten fluoride media. The main results of this work lead to the conclusions that: The solvents to be used for efficient separation must be fluoride media containing lithium as cation. Inert substrates are suitable for actinide/lanthanide separation; nickel substrate is more suitable for the extraction of lanthanides from the solvent, owing to the depolarisation occurring in the cathodic process through alloy formation.

  4. Lanthanide-containing polycations for monitoring polyplex dynamics via lanthanide resonance energy transfer.

    PubMed

    Kelkar, Sneha S; Xue, Lian; Turner, S Richard; Reineke, Theresa M

    2014-05-12

    Theranostic nanomaterials have emerged in the past decade that combine therapeutic delivery and diagnostic imaging into one package. Such materials offer the opportunity to aid diagnosis, track therapeutic biodistribution, and monitor drug release. We have developed a series of nucleic acid delivery polymers containing oligoethylene amines that are able to be protonated at physiological pH (for binding/compacting pDNA) and a lanthanide-chelating domain, which imparts diagnostic functionality. Diamine monomers (containing between 3 and 6 Boc-protected ethyleneamines) were prepared via a multistep procedure involving the selective protection and deprotection of primary and secondary amines. The polymer structures were then synthesized by step-growth polymerization of the oligoethylene diamines with a bisanhydride of diethylenetriamine pentaacetic acid (DTPA-BA), yielding degrees of polymerization between 18 and 24. Chelation of the polymers with gadolinium and terbium was performed to offer MRI contrast agent and luminescence properties, respectively. All of the polymer chelates were found to house approximately one water coordination site, as calculated by the Horrock's equation and possess longitudinal relaxivities (r1, on a per Gd basis) at least twice that of Magnevist, a clinical contrast agent. All the structures formed polyplexes with pDNA with highly positive zeta potentials and hydrodynamic diameters around 50-80 nm. Lanthanide resonance energy transfer (LRET) was used to monitor polyplex association and dissociation. Polyplexes were formed using the donor-acceptor pair comprising of terbium-chelated polymer with five ethyleneamines within the repeat unit (6c-Tb) and tetramethyl rhodamine (TMR)-labeled pDNA. Association/dissociation in the presence of heparin and NaCl was monitored. The effect of amine number along the polymer backbone on transfection efficiency and cytotoxicity was also investigated. None of the polymers revealed cytotoxic effects with

  5. Reduction of FCCI effects in lanthanide-iron diffusion couples by doping with palladium

    NASA Astrophysics Data System (ADS)

    Egeland, G. W.; Mariani, R. D.; Hartmann, T.; Porter, D. L.; Hayes, S. L.; Kennedy, J. R.

    2013-09-01

    Fast-reactor metallic fuels produce lanthanide fission products which have been shown to diffuse to the fuel periphery. Lanthanides interacting with the cladding is one cause of fuel-cladding chemical interaction. To test the viability of reducing the interaction by pinning these lanthanides, palladium was chosen as a fuel dopant based on the lanthanide-palladium intermetallic thermodynamic stability and fuel compatibility. Three lanthanides were tested, neodymium, cerium, and praseodymium, along with their 1:1 palladium compounds, against iron using diffusion couples. These experiments show the direct contact effect on iron of each lanthanide and its respective palladium compound at temperatures from 580 °C to 700 °C for 100 h.

  6. Dynamic tests for actinide/lanthanide separation by CMPO solvent in fluorinated diluents

    SciTech Connect

    Tkachenko, L.; Babain, V.; Alyapyshev, M.; Vizniy, A.; Il'in, A.; Shadrin, A.

    2013-07-01

    Actinide and lanthanide extraction by new solvent: 0.2 M phenyl-octyl-N,N-diiso-butylcarbamoyl-phosphine oxide (CMPO) + 30% TBP + formal of octafluoro-pentanol was studied. A dynamic test with this solvent was performed. It was shown that americium and lanthanides are effectively extracted from PUREX process raffinate. The separation of americium from light lanthanides was confirmed in the modified SETFICS flowsheet with this new solvent. (authors)

  7. Extraction of trivalent lanthanides and actinides by ``CMPO-like`` calixarenes

    SciTech Connect

    Delmau, L.H.; Simon, N.; Schwing-Weill, M.J.

    1999-04-01

    Extractive properties of calix[4]arenes bearing carbamoylmethylphosphine oxide moieties on their upper rim toward trivalent lanthanide and actinide cations were investigated. The study revealed that these molecules selectively extract light lanthanides and actinides from heavy lanthanides. All parameters present in the extraction system were varied to determine the origin of the selectivity. It was found that this selectivity requires a calix[4]arene platform and acetamidophosphine oxide groups containing phenyl substituents on the four phosphorus atoms.

  8. Selective Separation of Trivalent Actinides from Lanthanides by Aqueous Processing with Introduction of Soft Donor Atoms

    SciTech Connect

    Kenneth L. Nash

    2009-09-22

    Implementation of a closed loop nuclear fuel cycle requires the utilization of Pu-containing MOX fuels with the important side effect of increased production of the transplutonium actinides, most importantly isotopes of Am and Cm. Because the presence of these isotopes significantly impacts the long-term radiotoxicity of high level waste, it is important that effective methods for their isolation and/or transmutation be developed. Furthermore, since transmutation is most efficiently done in the absence of lanthanide fission products (high yield species with large thermal neutron absorption cross sections) it is important to have efficient procedures for the mutual separation of Am and Cm from the lanthanides. The chemistries of these elements are nearly identical, differing only in the slightly stronger strength of interaction of trivalent actinides with ligand donor atoms softer than O (N, Cl-, S). Research being conducted around the world has led to the development of new reagents and processes with considerable potential for this task. However, pilot scale testing of these reagents and processes has demonstrated the susceptibility of the new classes of reagents to radiolytic and hydrolytic degradation. In this project, separations of trivalent actinides from fission product lanthanides have been investigated in studies of 1) the extraction and chemical stability properties of a class of soft-donor extractants that are adapted from water-soluble analogs, 2) the application of water soluble soft-donor complexing agents in tandem with conventional extractant molecules emphasizing fundamental studies of the TALSPEAK Process. This research was conducted principally in radiochemistry laboratories at Washington State University. Collaborators at the Radiological Processing Laboratory (RPL) at the Pacific Northwest National Laboratory (PNNL) have contributed their unique facilities and capabilities, and have supported student internships at PNNL to broaden their

  9. Transient isotachophoretic-electrophoretic separations of lanthanides with indirect laser-induced fluorescence detection.

    PubMed

    Church, M N; Spear, J D; Russo, R E; Klunder, G L; Grant, P M; Andresen, B D

    1998-07-01

    Indirect laser-induced fluorescence was used for the detection of several lanthanide species separated by capillary electrophoresis. Quinine sulfate was the fluorescent component of the background electrolyte, and α-hydroxyisobutyric acid was added as a complexing agent to enable the separation of analyte ions that have similar mobilities. The UV lines (333-364 nm) of an argon ion laser were used as the excitation source with a diode array detector for monitoring the fluorescent emission at 442 nm. Electrokinetic injections and transient isotachophoresis were implemented to stack the analyte ions into more concentrated zones. On-line preconcentration factors were determined to be ∼700 and resulted in limits of detection for La(3+), Ce(3+), Pr(3+), Nd(3+), Sm(3+), and Eu(3+) in the low-ppb range (6-11 nM).

  10. Analytical-scale separations of lanthanides : a review of techniques and fundamentals.

    SciTech Connect

    Nash, K. L.; Jensen, M. P.

    1999-10-27

    Separations chemistry is at the heart of most analytical procedures to determine the rare earth content of both man-made and naturally occurring materials. Such procedures are widely used in mineral exploration, fundamental geology and geochemistry, material science, and in the nuclear industry. Chromatographic methods that rely on aqueous solutions containing complexing agents sensitive to the lanthanide cationic radius and cation-exchange phase transfer reactions (using a variety of different solid media) have enjoyed the greatest success for these procedures. In this report, they will briefly summarize the most important methods for completing such analyses. they consider in some detail the basic aqueous (and two-phase) solution chemistry that accounts for separations that work well and offer explanations for why others are less successful.

  11. Nuclear and electronic relaxation in lanthanide solutions: (CH 3) 4N +/Gd 3+ repulsive ion pair in D 2O

    NASA Astrophysics Data System (ADS)

    Vigouroux, C.; Bardet, M.; Belorizky, E.; Fries, P. H.; Guillermo, A.

    1998-04-01

    The longitudinal relaxation rate and self-diffusion coefficient of the tetramethylammonium protons are investigated at 400 MHz in D 2O solutions of hydrated Gd 3+ paramagnetic impurities, without and with complexing NO 3- ions. The results are interpreted using the hypernetted chain approximation of the potential of mean force between the repulsive ions, approximated as charged hard spheres in discrete polar and polarizable water. The standard dipolar relaxation formalism of Solomon is valid for the Gd 3+ lanthanide, i.e. its electron relaxation time is much longer than the translational correlation time of the interionic Brownian diffusion. The coordination effect by NO 3- is analyzed.

  12. The lanthanides and yttrium in minerals of the apatite group; a review

    USGS Publications Warehouse

    Fleischer, Michael; Altschuler, Z.S.

    1982-01-01

    More than 1000 analyses have been tabulated of the distribution of the lanthanides and yttrium in minerals of the apatite group, recalculated to atomic percentages. Average compositions have been calculated for apatites from 14 types of rocks. These show a progressive change of composition from apatites of granitic pegmatites, highest in the heavy lanthanides and yttrium, to those from alkalic pegmatites, highest in the light lanthanides and lowest in yttrium. This progression is clearly shown in plots of S (= at % La+Ce+Pr) vs the ratio La/Nd and of S vs the ratio 100Y/(Y+Ln), where Ln is the sum of the lanthanides. Apatites of sedimentary phosphorites occupy a special position, being relatively depleted in Ce and relatively enriched in yttrium and the heavy lanthanides, consequences of deposition from sea water. Apatites associated with iron ores are close in composition to apatites of carbonatites, alkalic ultramafic, and ultramafic rocks, being enriched in the light lanthanides and depleted in the heavy lanthanides. Their compositions do not support the hypothesis of Parak that the Kiruna-type ores are of sedimentary origin. Table 9 and Figures 1-3 show the dependence of lanthanide distribution on the nature of the host rock. Although a given analysis of the lanthanides does not unequivocally permit certain identification of the host rock, it can indicate a choice of highly probable host rocks.

  13. Lanthanide Selective Sorbents: Self-Assembled Monolayers on Mesoporous Supports (SAMMS)

    SciTech Connect

    Fryxell, Glen E.; Wu, Hong; Lin, Yuehe; Shaw, Wendy J.; Birnbaum, Jerome C.; Linehan, John C.; Nie, Zimin; Kemner, Kenneth M.; Kelly, Shelley

    2004-11-01

    Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of the support). This lanthanide-specific ligand field is created by pairing a “hard” anionic Lewis base with a suitable synergistic ligand, in a favorable chelating geometry. Details of the synthesis, characterization, lanthanide binding studies, binding kinetics, competition experiments and sorbent regeneration studies are summarized.

  14. Lanthanide Selective Sorbents: Self-Assembled Monolayers on Mesoporous Supports (SAMMS)

    SciTech Connect

    Fryxell, Glen E.; Wu, Hong; Lin, Yuehe; Shaw, Wendy J.; Birnbaum, Jerome C.; Linehan, John C.; Nie, Zimin; Kemner, K. M.; Kelly, Shelley

    2004-11-01

    Through the marriage of mesoporous ceramics with self-assembled monolayer chemistry, the genesis of a powerful new class of environmental sorbent materials has been realized. By coating the mesoporous ceramic backbone with a monolayer terminated with a lanthanide-specific ligand, it is possible to couple high lanthanide binding affinity with the high loading capacity (resulting from the extremely high surface area of the support). This lanthanide-specific ligand field is created by pairing a ''hard'' anionic Lewis base with a suitable synergistic ligand, in a favorable chelating geometry. Details of the synthesis, characterization, lanthanide binding studies, binding kinetics, competition experiments and sorbent regeneration studies are summarized

  15. Superabsorbing gel for actinide, lanthanide, and fission product decontamination

    DOEpatents

    Kaminski, Michael D.; Mertz, Carol J.

    2016-06-07

    The present invention provides an aqueous gel composition for removing actinide ions, lanthanide ions, fission product ions, or a combination thereof from a porous surface contaminated therewith. The composition comprises a polymer mixture comprising a gel forming cross-linked polymer and a linear polymer. The linear polymer is present at a concentration that is less than the concentration of the cross-linked polymer. The polymer mixture is at least about 95% hydrated with an aqueous solution comprising about 0.1 to about 3 percent by weight (wt %) of a multi-dentate organic acid chelating agent, and about 0.02 to about 0.6 molar (M) carbonate salt, to form a gel. When applied to a porous surface contaminated with actinide ions, lanthanide ions, and/or other fission product ions, the aqueous gel absorbs contaminating ions from the surface.

  16. Deep-UV biological imaging by lanthanide ion molecular protection

    PubMed Central

    Kumamoto, Yasuaki; Fujita, Katsumasa; Smith, Nicholas Isaac; Kawata, Satoshi

    2015-01-01

    Deep-UV (DUV) light is a sensitive probe for biological molecules such as nucleobases and aromatic amino acids due to specific absorption. However, the use of DUV light for imaging is limited because DUV can destroy or denature target molecules in a sample. Here we show that trivalent ions in the lanthanide group can suppress molecular photodegradation under DUV exposure, enabling a high signal-to-noise ratio and repetitive DUV imaging of nucleobases in cells. Underlying mechanisms of the photodegradation suppression can be excitation relaxation of the DUV-absorptive molecules due to energy transfer to the lanthanide ions, and/or avoiding ionization and reactions with surrounding molecules, including generation of reactive oxygen species, which can modify molecules that are otherwise transparent to DUV light. This approach, directly removing excited energy at the fundamental origin of cellular photodegradation, indicates an important first step towards the practical use of DUV imaging in a variety of biological applications. PMID:26819825

  17. Lanthanides caged by the organic chelates; structural properties.

    PubMed

    Smentek, Lidia

    2011-04-13

    The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

  18. A self-assembling lanthanide molecular nanoparticle for optical imaging†

    PubMed Central

    Brown, Katherine A.; Yang, Xiaoping; Schipper, Desmond; Hall, Justin W.; DePue, Lauren J.; Gnanam, Annie J.; Arambula, Jonathan F.; Jones, Jessica N.; Swaminathan, Jagannath; Dieye, Yakhya; Vadivelu, Jamuna; Chandler, Don J.; Marcotte, Edward M.; Sessler, Jonathan L.; Ehrlich, Lauren I. R.; Jones, Richard A.

    2015-01-01

    Chromophores that incorporate f-block elements have considerable potential for use in bioimaging applications because of their advantageous photophysical properties compared to organic dye, which are currently widely used. We are developing new classes of lanthanide-based self-assembling molecular nanoparticles as reporters for imaging and as multi-functional nanoprobes or nanosensors for use with biological samples. One class of these materials, which we call lanthanide “nano-drums”, are homogeneous 4d–4f clusters approximately 25 to 30 Å in diameter. These are capable of emitting from the visible to near-infrared wavelengths. Here, we present the synthesis, crystal structure, photophysical properties and comparative cytotoxicity data for a 32 metal Eu-Cd nano-drum [Eu8Cd24L12(OAc)48] (1). We also explored the imaging capabilities of this nano-drum using epifluorescence, TIRF, and two-photon microscopy platforms. PMID:25512085

  19. Magnetic hysteresis in a lanthanide molecular magnet dimer system

    NASA Astrophysics Data System (ADS)

    Atkinson, James; Cebulka, Rebecca; Del Barco, Enrique; Roubeau, Olivier; Velasco, Veronica; Barrios, Leo; Aromi, Guillem

    Molecular magnets present a wonderful means for studying the dynamics of spin. Often synthesized as a crystal lattice of identical systems, ensemble measurements enable thorough detailing of the internal degrees of freedom. Here we present the results of characterization performed on a dimer system, CeTm(HL)2(H2L)NO3pyH2O (L = ligand, C45H31O15N3), consisting of two lanthanide spins (Cerium and Thulium) with expected local axial anisotropies tilted with respect to each other. Microwave EPR spectroscopy at low temperature reveals hysteresis in observed absorption features, with angle dependence studies indicating the presence of several ``easy axis'' orientations. We attempt to understand this system through modelling via a spin Hamiltonian, and to determine the strength and nature of the coupling between the lanthanide centers. This research was funded through NSF Grant # 24086159.

  20. Lanthanides caged by the organic chelates; structural properties

    NASA Astrophysics Data System (ADS)

    Smentek, Lidia

    2011-04-01

    The structure, in particular symmetry, geometry and morphology of organic chelates coordinated with the lanthanide ions are analyzed in the present review. This is the first part of a complete presentation of a theoretical description of the properties of systems, which are widely used in technology, but most of all, in molecular biology and medicine. The discussion is focused on the symmetry and geometry of the cages, since these features play a dominant role in the spectroscopic activity of the lanthanides caged by organic chelates. At the same time, the spectroscopic properties require more formal presentation in the language of Racah algebra, and deserve a separate analysis. In addition to the parent systems of DOTA, DOTP, EDTMP and CDTMP presented here, their modifications by various antennas are analyzed. The conclusions that have a strong impact upon the theory of the energy transfer and the sensitized luminescence of these systems are based on the results of numerical density functional theory calculations.

  1. Interfacial Structure in Silicon Nitride Sintered with Lanthanide Oxide

    SciTech Connect

    Dwyer, C.; Ziegler, A.; Shibata, Naoya; Winkelman, G. B.; Satet, R. L.; Hoffmann, M. J.; Cinibulk, M. K.; Becher, Paul F; Painter, Gayle S; Browning, N. D.; Cockayne, D.J.H.; Ritchie, R O; Pennycook, Stephen J

    2006-01-01

    Three independent research groups present a comparison of their structural analyses of prismatic interfaces in silicon nitride densified with the aid of lanthanide oxide Ln{sub 2}O{sub 3}. All three groups obtained scanning transmission electron microscope images which clearly reveal the presence of well-defined Ln segregation sites at the interfaces, and, moreover, reveal that these segregation sites are element-specific. While some results differ across the three research groups, the vast majority exhibits good reproducibility.

  2. Lanthanide ions as spectral converters for solar cells.

    PubMed

    van der Ende, Bryan M; Aarts, Linda; Meijerink, Andries

    2009-12-21

    The use of lanthanide ions to convert photons to different, more useful, wavelengths is well-known from a wide range of applications (e.g. fluorescent tubes, lasers, white light LEDs). Recently, a new potential application has emerged: the use of lanthanide ions for spectral conversion in solar cells. The main energy loss in the conversion of solar energy to electricity is related to the so-called spectral mismatch: low energy photons are not absorbed by a solar cell while high energy photons are not used efficiently. To reduce the spectral mismatch losses both upconversion and downconversion are viable options. In the case of upconversion two low energy infrared photons that cannot be absorbed by the solar cell, are added up to give one high energy photon that can be absorbed. In the case of downconversion one high energy photon is split into two lower energy photons that can both be absorbed by the solar cell. The rich and unique energy level structure arising from the 4f(n) inner shell configuration of the trivalent lanthanide ions gives a variety of options for efficient up- and downconversion. In this perspective an overview will be given of recent work on photon management for solar cells. Three topics can be distinguished: (1) modelling of the potential impact of spectral conversion on the efficiency of solar cells; (2) research on up- and downconversion materials based on lanthanides; and (3) proof-of-principle experiments. Finally, an outlook will be given, including issues that need to be resolved before wide scale application of up- and downconversion materials can be anticipated.

  3. Ultracold lanthanides: from optical clock to a quantum simulator

    NASA Astrophysics Data System (ADS)

    Vishnyakova, G. A.; Golovizin, A. A.; Kalganova, E. S.; Sorokin, V. N.; Sukachev, D. D.; Tregubov, D. O.; Khabarova, K. Yu; Kolachevsky, N. N.

    2016-02-01

    We review the current research on precision spectroscopy and quantum optics applications of laser-cooled lanthanides. We discuss the specific electronic structure of hollow atoms, which determine prospects for application in optical frequency standards and in quantum simulators based on spin interactions in optical lattices. Using the example of the thulium atom, we describe the specifics of laser cooling, optical lattice trapping techniques, and clock transition spectroscopy using spectrally narrow lasers.

  4. Magnetic ordering in lanthanide-molybdenum oxide nanostructure arrays

    NASA Astrophysics Data System (ADS)

    Hagmann, Joseph; Le, Son; Schneemeyer, Lynn; Olsen, Patti; Besara, Tiglet; Siegrist, Theo; Seiler, David; Richter, Curt

    Reduced ternary molybdenum oxides, or bronzes, offer an attractive materials platform to study a wide variety of remarkable physical phenomena in a system with highly varied structural chemistry. Interesting electronic behaviors, such as superconductivity, charge density waves, and magnetism, in these materials arise from the strong hybridization of the 4d states of high-valent Mo with O p orbitals. We investigate a series of molybdenum bronze materials with Lanthanide-Mo16O44 composition that can be described as a three-dimensional array of metallic Mo8O32 nanostructures computationally predicted to contain a single charge with spin 1/2 separated by insulating MoO4 tetrahedra. This study reveals novel magnetic ordering in Lanthanide-Mo16O44 systems arising, not from the inclusion of magnetic elements, but rather from an exchange interaction between cubic Mo8O32 units. Here, we report the magnetometry and transport behaviors of a series of Lanthanide-Mo16O44 materials, emphasizing an observed low-temperature phase transition signifying the onset of antiferromagnetic ordering between the arrayed nanostructures, and relate these behaviors to their experimentally-characterized structures to reveal the intriguing physics of these correlated electronic systems.

  5. Characterization and Classification of Lanthanides by Multivariate-Analysis Methods

    NASA Astrophysics Data System (ADS)

    Horovitz, Ossi; Sârbu, Costel

    2005-03-01

    A chemometric study was conducted on a data set consisting of 18 characteristics, mainly physical properties of the 14 lanthanides and lanthanum, including Sc and Y. Classical methods of multivariate analysis, namely, principal component analysis (PCA) and cluster analysis (CA) were applied. The results obtained by using the Statistica software package are presented and discussed concerning the correlations between the properties and those between the elements themselves. The discussion and findings are based on the tables of correlation, the eigenvectors and eigenvalues of PCA, the 2D- and 3D-representations of the loadings of variables and scores of the elements corresponding to the first principal components, including also the dendrograms obtained by using CA. Loadings scatterplots are used as a display tool for examining the relationships between properties, looking for trends, grouping, or outliers. In the same way, the scatterplots of scores emphasized the difference between La and the lanthanides on the one side and Sc and Y on the other and support setting Lu as their homologue, rather than La. On the basis of these findings, a ”periodic system“ of the lanthanides is suggested that agrees well with chemical intuition.

  6. Probing the difference in covalence by enthalpy measurements: a new heterocyclic N-donor ligand for actinide/lanthanide separation.

    PubMed

    Yang, Yanqiu; Liu, Jun; Yang, Liang; Li, Kun; Zhang, Huabei; Luo, Shunzhong; Rao, Linfeng

    2015-05-21

    Complexation of Am(III), Nd(III), and Eu(III) with a new heterocyclic nitrogen-donor ligand, 2,9-di(quinazolin-2-yl)-1,10-phenanthroline (denoted as BQPhen in this paper), was studied by thermodynamic measurements and theoretical computations. The stability constants of two successive complexes in dimethylformamide, ML(3+) and ML2(3+) where M stands for Nd, Eu, or Am while L stands for the BQPhen ligand, were determined by absorption spectrophotometry. The enthalpy of complexation was determined by microcalorimetry. Results show that BQPhen forms ten times stronger complexes with Am(III) than Eu(III) or Nd(III) under identical conditions, suggesting that BQPhen could be used as an efficient extractant for the separations of trivalent actinides from lanthanides. The higher binding strength of BQPhen towards Am(III) than Nd(III) or Eu(III) is mainly due to the more favourable enthalpy of complexation for Am(III)/BQPhen complexes, implying a higher degree of covalence in the Am(III)/BQPhen complexes than the lanthanide(III)/BQPhen complexes. The thermodynamic trend was corroborated with computational results and validated by solvent extraction experiments that demonstrated BQPhen preferably extracted Am(III) more than Eu(III), with a separation factor of about 10. Discussions have been made to compare BQPhen with other phenanthroline derivatives such as CyMe4-BTPhen, a bis-triazine-phenanthroline derivative that was reported in the literature. Data suggest that, under identical conditions, BQPhen would form stronger complexes with Am(III), Eu(III), and Nd(III) than CyMe4-BTPhen.

  7. Supramolecular architectures from the self-assembly of lanthanide ions with 6-hydroxypicolinic acid and 1,10-phenanthroline

    NASA Astrophysics Data System (ADS)

    Sun, Chang-Yan; Jin, Lin-Pei

    2005-05-01

    Three new lanthanide complexes, [La(HpicO) 3(phen)(H 2O)] n ( 1) and Ln 3(picO) 4(phen) 3(H 2O) 2·HpicO·0.5H 2O (Ln=Er ( 2), Yb ( 3)) were synthesized by the hydrothermal reactions and characterized by single crystal X-ray diffraction, elemental analysis and IR spectrum. In complex 1, each La(III) ion is 10-coordinated and HpicO - ligands link the metal ions into 1D zigzag chains. Complexes 2 and 3 are isomorphous, and there are three crystallographically independent Ln(III) ions in the asymmetric unit. The N-H⋯O and O-H⋯O hydrogen bonds and π-π stacking interactions in these complexes result in the formation of 3D supramolecular architectures.

  8. Novel lanthanide pH fluorescent probes based on multiple emissions and its visible-light-sensitized feature.

    PubMed

    Lin, Jintai; Zheng, Yuhui; Wang, Qianming; Zeng, Zhi; Zhang, Cheng Cheng

    2014-08-11

    A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been presented. Compared to pure ligand, the complex offers more distinguished color changes (green-red-blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. During the concentration dependence experiments, the photoluminescence studies on the complex showed that the excitation of this pH probe can occur at a very long wavelength which extends to visible range (Ex=427 nm). Furthermore, the functional complex was successfully incorporated into soft networks and two novel luminescent hydrogels (rod and film) were fabricated. The soft materials also exhibited specific responses towards the pH variation. Finally, the onion cell-stain experiments were carried out to further confirm the validity of pH dependence and the results support the idea that the material will be suitable for monitoring biological samples in the future. PMID:25066718

  9. Novel lanthanide pH fluorescent probes based on multiple emissions and its visible-light-sensitized feature.

    PubMed

    Lin, Jintai; Zheng, Yuhui; Wang, Qianming; Zeng, Zhi; Zhang, Cheng Cheng

    2014-08-11

    A new type of Eu(III) ofloxacin complex as the fluorescent pH indicator has been presented. Compared to pure ligand, the complex offers more distinguished color changes (green-red-blue) derived from both lanthanide line emissions and the secondary ionization steps of ofloxacin. During the concentration dependence experiments, the photoluminescence studies on the complex showed that the excitation of this pH probe can occur at a very long wavelength which extends to visible range (Ex=427 nm). Furthermore, the functional complex was successfully incorporated into soft networks and two novel luminescent hydrogels (rod and film) were fabricated. The soft materials also exhibited specific responses towards the pH variation. Finally, the onion cell-stain experiments were carried out to further confirm the validity of pH dependence and the results support the idea that the material will be suitable for monitoring biological samples in the future.

  10. Early-Lanthanide(III) Acetonitrile-Solvento Adducts with Iodide and Noncoordinating Anions.

    PubMed

    Brown, Jessie L; Davis, Benjamin L; Scott, Brian L; Gaunt, Andrew J

    2015-12-21

    Dissolution of LnI3 (Ln = La, Ce) in acetonitrile (MeCN) results in the highly soluble solvates LnI3(MeCN)5 [Ln = La (1), Ce (2)] in good yield. The ionic complex [La(MeCN)9][LaI6] (4), containing a rare homoleptic La(3+) cation and anion, was also isolated as a minor product. Extending this chemistry to NdI3 results in the consistent formation of the complex ionic structure [Nd(MeCN)9]2[NdI5(MeCN)][NdI6][I] (3), which contains an unprecedented pentaiodide lanthanoid anion. Also described is the synthesis, isolation, and structural characterization of several homoleptic early-lanthanide MeCN solvates with noncoordinating anions, namely, [Ln(MeCN)9][AlCl4]3 [Ln = La (5), Ce (6), Nd (7)]. Notably, complex 6 is the first homoleptic cerium MeCN solvate reported to date. All reported complexes were structurally characterized by X-ray crystallography, as well as by IR spectroscopy and CHN elemental analysis. Complexes 1-3 were also characterized by thermogravimetric analysis coupled with mass spectrometry to further elucidate their bulk composition in the solid-state.

  11. Early-lanthanide(III) acetonitrile–solvento adducts with iodide and noncoordinating anions

    SciTech Connect

    Brown, Jessie L.; Davis, Benjamin L.; Scott, Brian L.; Gaunt, Andrew J.

    2015-12-25

    Dissolution of LnI3 (Ln = La, Ce) in acetonitrile (MeCN) results in the highly soluble solvates LnI3(MeCN)5 [Ln = La (1), Ce (2)] in good yield. The ionic complex [La(MeCN)9][LaI6] (4), containing a rare homoleptic La3+ cation and anion, was also isolated as a minor product. Extending this chemistry to NdI3 results in the consistent formation of the complex ionic structure [Nd(MeCN)9]2[NdI5(MeCN)][NdI6][I] (3), which contains an unprecedented pentaiodide lanthanoid anion. Also described is the synthesis, isolation, and structural characterization of several homoleptic early-lanthanide MeCN solvates with noncoordinating anions, namely, [Ln(MeCN)9][AlCl4]3 [Ln = La (5), Ce (6), Nd (7)]. Notably, complex 6 is the first homoleptic cerium MeCN solvate reported to date. All reported complexes were structurally characterized by X-ray crystallography, as well as by IR spectroscopy and CHN elemental analysis. Furthermore, complexes 1–3 were also characterized by thermogravimetric analysis coupled with mass spectrometry to further elucidate their bulk composition in the solid-state.

  12. Selective Removal of Lanthanides from Natural Waters, Acidic Streams and Dialysate

    SciTech Connect

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, Raymond S.; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

    2009-09-15

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, increasing public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd, Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS®) that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (ProPhos), and 1-hydroxy-2-pyridinone (1,2-HOPO) from natural waters (river, ground, and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate and compares their performance to a high surface area activated carbon. The properties include sorption affinity, capacity, and sorption kinetics. Stability and regenerability of SAMMS materials were also investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. While the activated carbon is as effective as 1,2-HOPO-SAMMS for capturing lanthanides in natural (alkaline) waters, it has no affinity in acid solutions (pH 2.4) and low affinity in carbonate-rich dialysate. Over 99% of 100 ug/L of Gd in dialysate was removed by the ProPhos-SAMMS after ten minutes. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties, for a number of regeneration cycles. In acid solutions, PhoPhos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their potential for chromatographic lanthanide separations. Thus, SAMMS materials have a great potential to be used as sorbents in large scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and sorbent dialyzers for lanthanide clearances.

  13. Selective removal of lanthanides from natural waters, acidic streams and dialysate

    PubMed Central

    Yantasee, Wassana; Fryxell, Glen E.; Addleman, R. Shane; Wiacek, Robert J.; Koonsiripaiboon, View; Pattamakomsan, Kanda; Sukwarotwat, Vichaya; Xu, Jide; Raymond, Kenneth N.

    2009-01-01

    The increased demand for the lanthanides in commercial products result in increased production of lanthanide containing ores, which increases public exposure to the lanthanides, both from various commercial products and from production wastes/effluents. This work investigates lanthanide (La, Ce, Pr, Nd, Eu, Gd and Lu) binding properties of self-assembled monolayers on mesoporous silica supports (SAMMS™), that were functionalized with diphosphonic acid (DiPhos), acetamide phosphonic acid (AcPhos), propionamide phosphonic acid (Prop-Phos), and 1-hydroxy-2-pyridinone (1,2-HOPO), from natural waters (river, ground and sea waters), acid solutions (to mimic certain industrial process streams), and dialysate. The affinity, capacity, and kinetics of the lanthanide sorption, as well as regenerability of SAMMS materials were investigated. Going from the acid side over to the alkaline side, the AcPhos- and DiPhos-SAMMS maintain their outstanding affinity for lanthanides, which enable the use of the materials in the systems where the pH may fluctuate. In acid solutions, Prop-Phos- and 1,2-HOPO-SAMMS have differing affinity along the lanthanide series, suggesting their use in chromatographic lanthanide separation. Over 95% of 100 µg/L of Gd in dialysate was removed by the Prop-Phos-SAMMS after 1 min and 99% over 10 min. SAMMS can be regenerated with an acid wash (0.5 M HCl) without losing the binding properties. Thus, they have a great potential to be used as in large-scale treatment of lanthanides, lanthanide separation prior to analytical instruments, and in sorbent dialyzers for treatment of acute lanthanide poisoning. PMID:19345006

  14. Raman and absorption spectrophotometric studies of selected lanthanide, californium-doped lanthanide, and actinide trihalides in the solid state

    SciTech Connect

    Wilmarth, W.R.

    1988-03-01

    The solid-state absorption spectra of Cf(III) ions as a dopant in lanthanide trihalide hosts (LnCl/sub 3/: Ln = Ce, Sm, and Y; LnBr/sub 3/: Ln = Ce, Sm, Tb, and Y; LnI/sub 3/: Ln = Ce and Y) have been recorded. The spectra of Cf(III) have been correlated with the various crystal structures. The phonon Raman spectra and solid-state absorption spectra of PmF/sub 3/, PmCl/sub 3/, PmBr/sub 3/, and two crystal modifications of PmI/sub 3/ have been recorded. Symmetry assignments have been made for the Raman-active bands for these trihalides and also the sesquioxide. The room-temperature absorption spectra have been correlated to crystal field effects. The symmetry assignments of the Raman-active phonon modes have been made based on polarized Raman spectra from single crystals of YF/sub 3/-type orthorhombic TbF/sub 3/ and PuBr/sub 3/-type orthorhombic NdBr/sub 3/. Raman spectra of other isostructural lanthanide compounds have been recorded and compared. Symmetry assignments for these compounds have been made by analogy to the single-crystal assignments. Raman spectra have been obtained and catalogued for a number of actinide compounds. Symmetry assignments have been made for the observed Raman-active phonon bands in this work based on the assignments made for isostructural lanthanide compounds. 29 figs., 22 tabs.

  15. Polyaminocarboxylic acids as potential candidates for trivalent actinide/lanthanide separations

    NASA Astrophysics Data System (ADS)

    Kissel, Daniel S.

    Nuclear energy, which has historically been considered an alternative energy solution in the United States, is regaining support as an efficient means of energy production. The viability of nuclear energy for the future, however, will remain suspect until issues involving the waste created are fully addressed in the next generation of advanced nuclear fuel cycles. The TALSPEAK process, developed at Oak Ridge National Laboratory, is a classic solvent extraction technique that employs a series of analytical separations in an effort to remove radioactive contaminants from spent nuclear fuel (SNF) and recover uranium in high purity. This separation utilizes a polyaminocarboxylic acid and a phosphorous extractant to separate trivalent actinides (An(III)s) from trivalent lanthanides (Ln(III)s). Conversely, issues with these reagents have hampered TALSPEAK's implementation as an industrial scale solution. The process requires a high concentration of lactic acid to facilitate phase separations, and the An(III)/Ln(III) separation factor is too low to achieve the purity required for artificial transmutation. Artificial transmutation involves steady neutron irradiation, which is impossible in the presence of Ln(III)s because of large neutron capture cross-sections. It is therefore critical to develop superior solvent extractants that effectively separate An(III)s from Ln(III)s. The present study focuses on the design, synthesis, characterization and analysis of advanced polyaminocarboxylic acids and their metal complexes in an effort to identify potential TALSPEAK-type extractants with superior separation properties. A facile, higher yield synthesis of these ligands and their complexation of trivalent metal ions (Co(III), Al(III), Ga(III), and In(III)), and selected lanthanides are reported. The polyaminocarboxylic acids and their trivalent metal complexes were characterized by elemental analysis, mass spectrometry, IR spectroscopy and NMR spectroscopy. Quantum mechanical

  16. Synthesis and characterization of Lanthanide Aluminotungstates and Rhenium Polyoxometalates: Potential Application in Molecular Information Storage Devices

    NASA Astrophysics Data System (ADS)

    Bian, Fang

    2011-12-01

    Polyoxometalates (abbreviated as POMs) are metal-oxide clusters with frameworks built from group 5 or 6 transition metals linked by shared oxide ions. The Keggin structure is one of the most famous structural forms of POMs. Keggin anions have a general formula of [XM12O40 ]n-, where X is a p-block atom and M is a transition metal atom such as W or Mo. Upon removal of one MO4+ unit from the Keggin anion, the monovacant structure [XM11O39] n- is formed. Those POMs that have lost one or more metal center are called lacunary POMs, which are very nice building blocks for the fabrication of coordination polymers. My research focuses on two facets of POM chemistry: 1) Lanthanide chemistry of aluminum tungstate monovacant Keggin and 2) Rhenium chemistry of aluminum tungstate Keggin and Wells-Dawson POM alpha1 -P2W17O61. In lanthanide POM research area, we obtained the following results: 1) The starting material aluminum tungstate monovacant Keggin α-K 9AlW12O39 was synthesized. Its single crystal was firstly identified by multinuclear NMR and X-ray crystallography. Its redox properties on the nano-scale solid state were determined by Conducting Electrostatic Force Mode (EFM) probes. It is well known that for POMs, a number of varies redox states are normally stable and reversible. Thus we estimated that POMs can potentially be used in molecular information storage applications, which we refer to as "redox disk drives". 2) Eight lanthanide aluminum tungstate Keggin complexes were synthesized. In their molecular structures (identified by multinuclear NMR and X-ray crystallography), each α-AlW11O39 is connected by lanthanide (III) cations to form 1D and 2D networks. All AlW11O39 Keggin POMs are regularly aligning on a flat plane. Microscopic data also verified that there is layer-by-layer morphology in this series of compounds. Overall, we postulate that aluminum tungstate Keggin POMs are a very promising materials for making future information storage device because they

  17. Series of dinuclear and tetranuclear lanthanide clusters encapsulated by salen-type and β-diketionate ligands: single-molecule magnet and fluorescence properties.

    PubMed

    Sun, Wen-Bin; Han, Bing-Lu; Lin, Po-Heng; Li, Hong-Feng; Chen, Peng; Tian, Yong-Mei; Murugesu, Muralee; Yan, Peng-Fei

    2013-10-01

    Three dinuclear [Ln2H2OL(1)2(acac)2]·solvent (1, Ln = Gd, solvent = 2CH2Cl2; 2, Ln = Tb, no solvent; 3, Ln = Er, solvent = (C2H5)2O), and two tetranuclear lanthanide clusters [Ln4(μ3-OH)2L(2)2(acac)6]·2(solvent) (4, Ln = Tb, solvent = CH3OH; 5, Ln = Dy, solvent = CH3CN) were characterized in terms of structure, fluorescence and magnetism. The dinuclear lanthanide complexes were constructed by a rigid salen-type ligand H2L(1) = N,N'-bis(salicylidene)-o-phenylenediamine and β-diketonate (acac = acetylacetonate) ligands, while the tetranuclear clusters were formed from the flexible ligand H2L(2) = N,N'-bis(salicylidene)-1,2-ethanediamine. Crystal structure analysis indicates that the rigid ligand favors the double-decker sandwich structure (Ln2L(1)2), in which the two lanthanide ions have different coordination numbers and geometry, while the more flexible ligand (H2L(2)) leads to planar tetranuclear clusters. The relationship between their respective magnetic anisotropy and ligand-field geometries and their fluorescence properties was investigated. The Dy and Tb-containing clusters exhibit typical visible fluorescence properties, and single-molecule magnet behavior is seen in complex 5.

  18. Fungus-promoted transformation of lanthanides during the biooxidation of divalent manganese

    NASA Astrophysics Data System (ADS)

    Yu, Qianqian; Ohnuki, Toshihiko; Tanaka, Kazuya; Kozai, Naofumi; Yamasaki, Shinya; Sakamoto, Fuminori; Tani, Yukinori

    2016-02-01

    Although microorganisms possess high sorption capability for lanthanides, the effect of their biological response on lanthanides migration is unclear. Using active fungus Acremonium strictum KR21-2, supplied with nutrients, this study compared the transformation of lanthanides during the biooxidation of Mn(II) in the absence and presence of trisodium citrate. In the absence of trisodium citrate, lanthanides were rapidly sorbed on fungal cells within 24 h, followed by the preferential desorption of Ce over other lanthanides as Mn oxide formed. Most of the desorbed Ce was in the colloidal phase and associated with a biomolecule produced by the active fungus. In contrast, neither desorption of Ce nor release of this biomolecule occurred in the presence of trisodium citrate. Most importantly, the Ce-binding biomolecule was not found to associate with any other trivalent lanthanides tested or with Fe. The biomolecule was characterized as c.a. 4700 Da in size, and it contains saccharides that differed from those non-nuclide-specific organic substances released from resting cells, as reported previously. This study highlights the importance of biotic reactions between lanthanides and microbial cells, which may affect the migration of lanthanides at the water-Mn oxide interface.

  19. Lanthanides in Metallic Nuclear Fuels: Their Behavior and Methods for Their Control

    SciTech Connect

    Robert D. Mariani; Douglas L. Porter; Thomas P. O'Holleran; Steven L. Hayes; J. Rory Kennedy

    2011-12-01

    The thermodynamic and experimental basis is given for using dopant additives to bind lanthanides as intermetallic compounds in metallic nuclear fuels. Lanthanide fission products are a major factor in limiting the lifetime of the fuel, because they migrate to the fuel slug peripheral surface where they participate in fuel-cladding chemical interactions (FCCI) with the steel cladding. Lanthanide carryover in recycled metal fuels can accelerate FCCI, as recycled lanthanides would likely segregate from the fuel phase, putting the lanthanides in prompt contact with the cladding. In out-of-pile tests we examined the use of Pd for binding the lanthanides, with Pd selected because of its known metallurgical properties in fuel related systems and because of its known behavior in irradiated EBR-II fuels. Initial results confirmed that palladium may be expected to mitigate FCCI arising from lanthanides, and it has been recommended for in-pile tests. We also evaluated transport phenomena responsible for lanthanide migration, and identified liquid-like behaviors as being dominant. Liquid-like behaviors include transport with liquid metals, liquid metal solutions, and rapid surface transport of alloys/metals near their melting temperatures. The analysis led to establishing general criteria for selecting alternate dopant additives, and identifying Sn, Sb, and Te as alternates for further testing.

  20. Lanthanide ion and tetrathiafulvalene-based ligand as a "magic" couple toward luminescence, single molecule magnets, and magnetostructural correlations.

    PubMed

    Pointillart, Fabrice; le Guennic, Boris; Cador, Olivier; Maury, Olivier; Ouahab, Lahcène

    2015-11-17

    The synthesis of molecules featuring different properties is a perpetual challenge for the chemists' community. The coexistence and even more the synergy of those properties open new perspectives in the field of molecular devices and molecular electronics. In that sense, coordination chemistry contributed to the development of new functional molecules through, for instance, single-molecule magnets (SMMs) and light emitting molecules with potential applications in high capacity data storage and OLEDs, respectively. The appealing combination of both electronic properties into one single object may offer the possibility to have magnetized luminescent entities at nanometric scale. To that end, lanthanides seem to be one of the key ingredients since their peculiar electronic structures endow them with specific magnetic and luminescence properties. Indeed, lanthanides cover a wide range of emission wavelengths, from infrared to UV, which add up to a large variety of magnetic behaviors, from the fully isotropic spin (e.g., Gd(III)) to highly anisotropic magnetic moments (e.g., Dy(III)). In lanthanide complexes, ligands play a fundamental role because on one hand they govern the orientation of the magnetic moment of anisotropic lanthanides and on the other hand they can sensitize efficiently the luminescence. The design of appropriate organic ligands to elaborate such chemical objects with the desired property appears to be essential but remains a perpetual challenge. In this Account, we describe the design of lanthanide-based complexes that emit light, behave as SMMs, or combine both properties. We have paid peculiar attention to the design of ligands based on the tetrathiafulvalene (TTF) moiety. TTF and its derivatives are well-known chemical entities, stable at different oxidation states, and employed mainly in the synthesis of molecular conductors and superconductors. In addition to their redox properties, TTF-based derivatives act as organic chromophores for the

  1. Lanthanide ion and tetrathiafulvalene-based ligand as a "magic" couple toward luminescence, single molecule magnets, and magnetostructural correlations.

    PubMed

    Pointillart, Fabrice; le Guennic, Boris; Cador, Olivier; Maury, Olivier; Ouahab, Lahcène

    2015-11-17

    The synthesis of molecules featuring different properties is a perpetual challenge for the chemists' community. The coexistence and even more the synergy of those properties open new perspectives in the field of molecular devices and molecular electronics. In that sense, coordination chemistry contributed to the development of new functional molecules through, for instance, single-molecule magnets (SMMs) and light emitting molecules with potential applications in high capacity data storage and OLEDs, respectively. The appealing combination of both electronic properties into one single object may offer the possibility to have magnetized luminescent entities at nanometric scale. To that end, lanthanides seem to be one of the key ingredients since their peculiar electronic structures endow them with specific magnetic and luminescence properties. Indeed, lanthanides cover a wide range of emission wavelengths, from infrared to UV, which add up to a large variety of magnetic behaviors, from the fully isotropic spin (e.g., Gd(III)) to highly anisotropic magnetic moments (e.g., Dy(III)). In lanthanide complexes, ligands play a fundamental role because on one hand they govern the orientation of the magnetic moment of anisotropic lanthanides and on the other hand they can sensitize efficiently the luminescence. The design of appropriate organic ligands to elaborate such chemical objects with the desired property appears to be essential but remains a perpetual challenge. In this Account, we describe the design of lanthanide-based complexes that emit light, behave as SMMs, or combine both properties. We have paid peculiar attention to the design of ligands based on the tetrathiafulvalene (TTF) moiety. TTF and its derivatives are well-known chemical entities, stable at different oxidation states, and employed mainly in the synthesis of molecular conductors and superconductors. In addition to their redox properties, TTF-based derivatives act as organic chromophores for the

  2. Core level photoelectron spectroscopy on the lanthanide-induced hydrolysis of DNA

    NASA Astrophysics Data System (ADS)

    Shigekawa, Hidemi; Ikawa, Hiroyuki; Yoshizaki, Ryozo; Iijima, Yoshitoki; Sumaoka, Jun; Komiyama, Makoto

    1996-03-01

    The electronic structures of the complexes of diphenyl phosphate (DPP), a model compound of DNA, with lanthanide ions have been investigated to shed light on the mechanism of the cerium (IV)-induced nonenzymatic hydrolysis of DNA. Binding energies of the P 2p core level of DPP were 134.2 eV for the complexes with La(III), Eu(III), and Lu(III), and was 134.4 eV for the Ce(IV) complex, when the metal/DPP molar ratio was 1:1. When the molar ratio was increased, only Ce(IV), the most active metal ion for DNA hydrolysis, showed a chemical shift of ˜0.5 eV toward the higher binding energy region. The chemical shift of ˜0.5 eV toward the higher binding energy region. The chemical shift was due to the systematic increase in the intensity of the higher binding energy component. The observed change in the electronic structure of the DPP-Ce(IV) complex may be related to the superb ability of Ce(IV) for the hydrolysis of DNA.

  3. Early-lanthanide(III) acetonitrile–solvento adducts with iodide and noncoordinating anions

    DOE PAGES

    Brown, Jessie L.; Davis, Benjamin L.; Scott, Brian L.; Gaunt, Andrew J.

    2015-12-25

    Dissolution of LnI3 (Ln = La, Ce) in acetonitrile (MeCN) results in the highly soluble solvates LnI3(MeCN)5 [Ln = La (1), Ce (2)] in good yield. The ionic complex [La(MeCN)9][LaI6] (4), containing a rare homoleptic La3+ cation and anion, was also isolated as a minor product. Extending this chemistry to NdI3 results in the consistent formation of the complex ionic structure [Nd(MeCN)9]2[NdI5(MeCN)][NdI6][I] (3), which contains an unprecedented pentaiodide lanthanoid anion. Also described is the synthesis, isolation, and structural characterization of several homoleptic early-lanthanide MeCN solvates with noncoordinating anions, namely, [Ln(MeCN)9][AlCl4]3 [Ln = La (5), Ce (6), Nd (7)]. Notably, complexmore » 6 is the first homoleptic cerium MeCN solvate reported to date. All reported complexes were structurally characterized by X-ray crystallography, as well as by IR spectroscopy and CHN elemental analysis. Furthermore, complexes 1–3 were also characterized by thermogravimetric analysis coupled with mass spectrometry to further elucidate their bulk composition in the solid-state.« less

  4. Spectroscopic system for direct lanthanide photoluminescence spectroscopy with nanomolar detection limits.

    PubMed

    Andolina, Christopher M; Holthoff, William G; Page, Phillip M; Mathews, Ryan A; Morrow, Janet R; Bright, Frank V

    2009-05-01

    A new spectroscopic system for direct photoluminescence of lanthanide ions (Ln(III)) through electronic transitions within the 4f(n) manifold is described. The system is based on an injection seeded frequency tripled (lambda = 355 nm) Nd:YAG pump laser coupled with a master oscillator power oscillator (MOPO). The MOPO delivers an average pulse energy of approximately 60 mJ/pulse, is continuously tunable from 425 to 690 nm (Signal) and 735 to 1800 nm (Idler) with a linewidth of <0.2 cm(-1), and has a pulse duration of 10-12 ns. Aqueous solutions containing two polyaminocarboxylate complexes, ethylenediaminetetraacetic acid (EDTA) and diethylenetriaminepentaacetic acid (DTPA), and Ln(3+) aqua ion for several lanthanides including Eu(III), Tb(III), Dy(III), and Sm(III)) are used as steady-state and time-resolved photoluminescence standards. The versatility of the instrument is demonstrated by excitation scans over a broad visible range for aqueous solutions of complexes of Eu(III), Dy(III), Sm(III), and Tb(III). The Eu(III) excitation band ((7)F(o)-->(5)D(o)) is recorded over a range of complex concentrations that are 1000-fold less than reported previously, including Eu(EDTA) (1.00 nM), Eu(DTPA) (1.00 nM), and Eu(III) aqua ion (50.0 nM). Emission spectra are recorded in the visible range for Ln(III) complexes at pH 6.5 and 1.00 mM. Excited-state lifetimes for the standards were constant as a function of concentration from 10.0 nM to 1.00 mM for Eu(EDTA) and Eu(DTPA) and from 100 nM to 1.00 mM for Eu(III) aqua ion. Photoluminescence lifetimes in H(2)O and D(2)O are recorded and used to calculate the number of bound water molecules for all complexes.

  5. Paramagnetic lanthanide chelates for multicontrast MRI.

    PubMed

    Cakić, Nevenka; Savić, Tanja; Stricker-Shaver, Janice; Truffault, Vincent; Platas-Iglesias, Carlos; Mirkes, Christian; Pohmann, Rolf; Scheffler, Klaus; Angelovski, Goran

    2016-07-28

    The preparation of a paramagnetic chelator that serves as a platform for multicontrast MRI, and can be utilized either as a T1-weighted, paraCEST or (19)F MRI contrast agent is reported. Its europium(iii) complex exhibits an extremely slow water exchange rate which is optimal for the use in CEST MRI. The potential of this platform was demonstrated through a series of MRI studies on tube phantoms and animals. PMID:27291157

  6. Equilibrium Speciation of Select Lanthanides in the Presence of Acidic Ligands in Homo- and Heterogeneous Solutions

    SciTech Connect

    Robinson, Troy A

    2011-08-01

    phase that becomes heterogeneous by the micellization of surfactants through the increase of temperature. To better understand the behavior of europium (Eu3+) and 8-hydroxyquinoline under cloud point extraction conditions, potentiometric and spectrophotometric titrations coupled with modeling with Hyperquad and SQUAD computer programs were performed to assess europium (Eu3+) and 8-hydroxyquinoline speciation. Experiments in both water and a 1wt% Triton X-114/water mixed solvent were compared to understand the effect of Triton X-114 on the system speciation. Results indicated that increased solvation of 8-hydroxyquinoline by the mixed solvent lead to more stable complexes involving 8-hydroxyquinoline than in water, whereas competition between hydroxide and Triton X-114 for Eu3+ led to lower stability hydrolysis complexes in the mixed solvent than in water. Lanthanide speciation is challenging due to the trivalent oxidation state that leads to multiple ligand complexes, including some mixed complexes. The complexity of the system demands well-designed and precise experiments that capture the nuances of the chemistry. This work increased the understanding of lanthanide speciation in the explored systems, but more work is required to produce a comprehensive understanding of the speciation involved.

  7. Centrifugal atomization of lanthanide materials for cryogenic coolers

    SciTech Connect

    Osborne, M.G.

    1994-01-04

    Until recently, Pb was the preferred heat exchanger matrix material used in low temperature cryocoolers; however, the heat capacity of Pb drops drastically below {approximately}15K and new matrix materials based on the lanthanide elements have been developed. These materials magnetically order at low temperatures and the entropy change associated with ordering contributes to the materials` heat capacities. The drawback to widespread use of lanthanide intermetallic compounds in cryocoolers has been the difficulty in manufacturing high-quality particulates. The purpose of this project was to develop a technique for producing high-quality powders of lanthanide metals and lanthanide intermetallic compounds for use in cryocooler heat exchangers. A series of atomization experiments was performed using Er{sub 3}Ni, Nd, Nd{sub 3}Ni, and (Er{sub 0.5}Nd{sub 0.5}){sub 3}Ni. Atomization of these materials resulted in particles ranging from mostly spherical to extremely flattened. Analyses of size distributions for the experiments indicate that increased atomization disk speed and superheat result in smaller mean particle diameters and narrower size distributions. Chemical analyses of the atomized powders indicate that the CA/RQB technique produces particulate with much lower interstitial contamination than other techniques. The Er{sub 3}Ni and Nd{sub 3}Ni powders were predominantly of the desired phase and the (Er{sub 0.5}Nd{sub 0.5}){sub 3}Ni powder had one major and possibly three minor phases. The solidification morphology is typically fine dendritic or cellular with finer microstructure spacings near the particle surfaces. The Er{sub 3}Ni powders have higher heat capacities than gas atomized powders reported in literature. The heat capacity of Nd{sub 3}Ni has a peak which does not degrade dramatically with processing. The (Er{sub 0.5}Nd{sub 0.5}){sub 3}Ni material has a higher heat capacity compared to Er{sub 3}Ni, Nd{sub 3}Ni, and Nd at temperatures above 10K.

  8. Surface X-ray emission from lanthanide metals

    NASA Astrophysics Data System (ADS)

    Hübinger, F.; Shulakov, A. S.; Starke, K.; Grigoriev, A.; Kaindl, G.

    2003-02-01

    O 3 X-ray emission (XE) upon 5p 3/2 electron-impact ionization of La(0 0 0 1) and Sm(0 0 0 1) metal surfaces exhibits up to 30% spectral intensity from the topmost atomic surface layer. The energy separation of surface and bulk XE peaks is explained by the surface core-level shift of La and the surface valence transition of Sm. While the bulk XE spectra are in reasonable agreement with theoretical sd partial density of states (DOS), the experimental access to the partial surface-layer DOS opens new opportunities in studying surface phenomena in lanthanide metals and compounds.

  9. N,N-dimethyldodecylamine oxide self-organization in the presence of lanthanide ions in aqueous and aqueous-decanol solutions.

    PubMed

    Selivanova, Natalia M; Galeeva, Aliya I; Sukhanov, Andrey A; Gnezdilov, Oleg I; Chachkov, Denis V; Galyametdinov, Yury G

    2013-05-01

    The article represents the results of research in self-organization of new lanthanide systems in water-decanol medium. The systems are based on N,N-dimethyldodecylamine oxide, a zwitterionic surfactant. The study covers the complex formation of lanthanide ions with C12DMAO molecules and the influence of Ln(III) ions and medium composition on surfactant association in diluted solutions. The analysis of adsorption isotherms was carried out on the basis of the combination of Gibbs and Langmuir adsorption equations. The results were used to determine physicochemical properties and parameters of a monomolecular adsorption layer. The research objects were various lanthanide ions with identical coordination centers. A number of spectroscopic methods (UV, NMR self-diffusion, EPR, dynamic light scattering (DLS), and fluorescent analysis) were involved in the research for comparative estimations of molecular dynamics, critical micellization concentration, geometry, sizes, and aggregation numbers of micellar aggregates. Micelle structure simulation revealed good agreement between experimental data and quantum chemical calculations. PMID:23557206

  10. Gadolinium speciation with Tetradentate, N-donor extractants for minor actinide/lanthanide separation: an XRD, mass spectrometry and EPR study

    SciTech Connect

    Whittaker, D.M.; Sharrad, C.A.; Sproules, S.

    2013-07-01

    The hydrophobic organic molecules CyMe{sub 4}-BTPhen (1) and CyMe{sub 4}-BTBP (2) have been developed and tuned over many years to be able to separate the trivalent actinides from the trivalent lanthanides (Ln) selectively in bi-phasic solvent extraction processes for the separation of the long-lived radio-toxic minor actinides from spent nuclear fuel. The ability of these N-donor ligands to perform this separation is poorly understood, as is their speciation with the metal ions when extracted into the organic phase. Our previous work has shown Ln{sup 3+} speciation to be largely 1:2 Ln:L in nature with another small molecule, either water or nitrate, occupying a cavity between the tetradentate bound N-donor ligands. The identity of the small molecule changes across the lanthanide series, and here we continue investigations into this speciation. Complexes of these N-donor ligands with Gd{sup 3+} have been synthesised and characterised by X-ray crystallography, mass spectrometry and EPR spectroscopy. We show that the N-donor ligands have no effect on the electronic configuration of Gd{sup 3+} and that the lanthanide contraction with the steric rigidity of the N-donor ligand appears to determine the size of the cavity between the coordinated ligands. This in turn appears to control the identity of the small molecule on the ninth site in the 1:2 Gd:L species. (authors)

  11. Thermodynamics and extraction modeling of trivalent lanthanides in the nuclear fuel cycle

    SciTech Connect

    Levitskaia, T.G.; Chatterjee, S.; Valerio, E.L.; Robinson, T.A.

    2013-07-01

    In this investigation, a combination of VPO (Vapor Pressure Osmometry) and water activity methods was applied to measure water activity and osmotic coefficients of binary lanthanide nitrate solutions at a temperature of 25 C. degrees. It was observed that the nature of the lanthanide nitrate has pronounced effect on the water activity in solution. In the solutions with the same Ln(NO{sub 3}){sub 3} molality, water activity is decreased in the order from the light to heavy lanthanides. This trend was explained by the contraction of the lanthanide ionic radii in the same order resulting in the [Ln(H{sub 2}O){sub n}]{sup 3+} (aq) hydration number of 9 for the early (La-Sm) and 8 for the late (Dy-Lu) lanthanides, with the intermediate metals exhibiting a mixture of eight and nine coordinate molecules. This results in the dissimilar effect of the light and heavy lanthanides on the water structure manifesting in the systematic changes of the water activity in the series of concentrated lanthanide solutions. Experimental water activity and osmotic coefficient data agree well with the literature for both 1:1 and 3:1 electrolyte systems. The Pitzer parameters obtained fitting these data are in an excellent agreement with the literature reported values for Ln(NO{sub 3}){sub 3} solutions.

  12. A remarkable enhancement in Am³⁺/Eu³⁺ selectivity by an ionic liquid based solvent containing bis-1,2,4-triazinyl pyridine derivatives: DFT validation of experimental results.

    PubMed

    Bhattacharyya, Arunasis; Ansari, Seraj A; Gadly, Trilochan; Ghosh, Sunil K; Mohapatra, Manoj; Mohapatra, P K

    2015-04-01

    Mutual separation of trivalent actinide (An(3+)) and lanthanide (Ln(3+)) using several soft (N) donor ligands (bis(5,6-dialkyl-1,2,4-triazinyl)pyridine (R-BTP)) is attempted for the first time in room temperature ionic liquid (RTIL) medium. The results indicate a spectacular enhancement in the selectivity as compared to that in molecular diluents with a separation factor (S.F.) of >3000 for Am(3+) over Eu(3+) using the methyl derivative (Me-BTP) in RTIL medium using [C(n)mim]·[NTf2] as the diluents (where n = 2, 3, 4, 6 or 8). Such a high S.F. value has never been reported before with any of the R-BTP derivatives in molecular diluents. An opposite trend in the distribution ratio values of both Am(3+) and Eu(3+) with the increasing size of the alkyl (R) group is observed in RTIL medium when compared with that in molecular diluents. The differences in the extraction behaviour of R-BTPs in RTILs vis-à-vis molecular diluents are explained on the basis of the difference in the nature of complexes extracted in these two distinctly different media as supported by the time resolved fluorescence (TRFS) study. An unusually high extractability and selectivity for Am(3+) over Eu(3+) with Me-BTP was attributed to the formation of a 1 : 4 complex for Am(3+), which was never reported earlier with any of the R-BTP derivatives in molecular diluents. DFT studies indicated higher metal 'd' and 'f' orbital participation (covalence) in the bonding with R-BTP in the case of Am(3+) complexes as compared to that in the case of Eu(3+) complexes, which resulted in the selectivity of these classes of ligands. The observed results may have a great significance in the radioactive waste management involving the partitioning and transmutation strategy. PMID:25736729

  13. Stabilization of actinides and lanthanides in unusually high oxidation states

    SciTech Connect

    Eller, P.G.; Penneman, R.A.

    1986-01-01

    Chemical environments can be chosen which stabilize actinides and lanthanides in unusually high or low oxidation states and in unusual coordination. In many cases, one can rationalize the observed species as resulting from strong charge/size influences provided by specific sites in host lattices (e.g., Tb(IV) in BaTbO/sub 3/ or Am(IV) in polytungstate anions). In other cases, the unusual species can be considered from an acid-base viewpoint (e.g., U(III) in AsF/sub 5//HF solution or Pu(VII) in Li/sub 5/PuO/sub 6/). In still other cases, an interplay of steric and redox effects can lead to interesting comparisons (e.g., instability of double fluoride salts of Pu(V) and Pu(VI) relative to U, Np, and Am analogues). Generalized ways to rationalize compounds containing actinides and lanthanides in unusual valences (particularly high valences), including the above and numerous other examples, will form the focus of this paper. Recently developed methods for synthesizing high valent f-element fluorides using superoxidizers and superacids at low temperatures will also be described. 65 refs., 8 figs., 9 tabs.

  14. Basic understanding of the lanthanide related upconversion emissions

    NASA Astrophysics Data System (ADS)

    Dong, Hao; Sun, Ling-Dong; Yan, Chun-Hua

    2013-06-01

    With abundant energy levels of 4f electron configurations, trivalent lanthanide ions (Ln3+) are endowed with unique and fascinating luminescent properties. Inheriting the native transition behaviour of the lanthanide ions, Ln3+ based nanomaterials have aroused great interest for a wide range of applications, including lighting and displays, optical fibers and amplifiers, responsive luminescent stains for biomedical analysis, in vivo and in vitro imaging, and enhancement for silicon solar cell devices. It should be noted that the application depends completely on the corresponding luminescent behaviour. To deepen the understanding of the luminescent mechanism is important for the developing of the field and the design of new Ln3+ based luminescent materials toward applications. In this review, we focused mainly on the recent developments on upconversion (UC) emission studies. Firstly, the emphasis was put on the introduction of basic luminescent properties of Ln3+ with f-f transitions, and then the corresponding mechanisms and properties of UC emission were discussed in detail, the potential researches with respect to UC mechanisms and properties were finally outlined.

  15. Purification of lanthanides for double beta decay experiments

    NASA Astrophysics Data System (ADS)

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Cappella, F.; Cerulli, R.; Danevich, F. A.; Incicchitti, A.; Laubenstein, M.; Mokina, V. M.; Nisi, S.; Poda, D. V.; Tretyak, V. I.

    2013-08-01

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain 238U, 226Ra and 232,228Th typically on the level of ˜ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO2, Nd2O3 and Gd2O3. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R&D of the methods to remove the pollutions with improved efficiency is in progress.

  16. Purification of lanthanides for double beta decay experiments

    SciTech Connect

    Polischuk, O. G.; Barabash, A. S.; Belli, P.; Bernabei, R.; Boiko, R. S.; Danevich, F. A.; Mokina, V. M.; Poda, D. V.; Tretyak, V. I.; Cappella, F.; Incicchitti, A.; Cerulli, R.; Laubenstein, M.; Nisi, S.

    2013-08-08

    There are several potentially double beta active isotopes among the lanthanide elements. However, even high purity grade lanthanide compounds contain {sup 238}U, {sup 226}Ra and {sup 232,228}Th typically on the level of ∼ (0.1 - 1) Bq/kg. The liquid-liquid extraction technique was used to remove traces of U, Ra and Th from CeO{sub 2}, Nd{sub 2}O{sub 3} and Gd{sub 2}O{sub 3}. The radioactive contamination of the samples before and after the purification was tested by using ultra-low-background HPGe γ spectrometry at the underground Gran Sasso National Laboratories of the INFN (Italy). After the purification the radioactive contamination of gadolinium oxide by Ra and Th was decreased at least one order of magnitude. The efficiency of the approach to purify cerium oxide from Ra was on same level, while the radioactive contamination of neodymium sample before and after the purification is below the sensitivity of analytical methods. The purification method is much less efficient for chemically very similar radioactive elements like lanthanum, lutetium and actinium. R and D of the methods to remove the pollutions with improved efficiency is in progress.

  17. Lanthanide Hydroxide Nanoparticles Induce Angiogenesis via ROS-Sensitive Signaling.

    PubMed

    Zhao, Haishan; Osborne, Olivia J; Lin, Sijie; Ji, Zhaoxia; Damoiseux, Robert; Wang, Yuqiang; Nel, André E; Lin, Shuo

    2016-08-01

    Recent studies suggest that the nanorods consisting of europium hydroxide could promote angiogenesis. In this study, it is sought to determine if additional types of nanoparticles are capable of enhancing angiogenesis and in addition, understand the underlying mechanisms. For this reason, a method is employed that combines a high throughput in vitro cell based screen coupled with an in vivo validation using vascular specific green fluorescent protein reporter transgenic zebrafish for examining proangiogenesis activity. After screening multiple types of nanoparticles, it is discovered that four of them, Eu(III) (OH)3 rods (Eu rods), Eu(III) (OH)3 spheres (Eu spheres), Tb(III) (OH)3 rods (Tb rods), and Tb(III) (OH)3 spheres (Tb spheres), are the most effective in promoting angiogenesis. It is also showed that ionic forms of europium nitrate [Eu(NO3 )3 ] (Eu) and terbium nitrate [Tb(NO3 )3 ] (Tb), the two lanthanide elements for these four nanoparticles, are also capable of enhancing angiogenesis. However, this effect is further enhanced by nanoparticle synthesis. Finally, it is demonstrated that reactive oxygen species H2 O2 is a key factor in the process of proangiogenesis by lanthanide elemental nanoparticles. PMID:27383397

  18. Lanthanide Ion Doped Upconverting Nanoparticles: Synthesis, Structure and Properties.

    PubMed

    Yan, Chenglin; Zhao, Haiguang; Perepichka, Dmitrii F; Rosei, Federico

    2016-08-01

    Lanthanide doped upconverting nanoparticles (UCNPs) have emerged as a new class of luminescent materials, with major discoveries and overall significant progress during the last decade. Unlike multiphoton absorption in organic dyes or semiconductor quantum dots, lanthanide doped UCNPs involve real intermediate quantum states and convert infrared (IR) into visible light via sequential electronic excitation. The relatively high efficiency of this process even at low radiation flux makes UCNPs particularly attractive for many current and emerging areas of technology. The aim of this article is to highlight several recent advances in this rapidly growing field, emphasizing the relationships between structure and properties of UCNPs. Additionally, various strategies developed for the synthesis of UCNPs with a focus on the various synthetic approaches that yield high-quality monodisperse samples with controlled size, shape and crystalline phase are reviewed. Emerging synthetic approaches towards designed structure to improve the optical and electronic properties of UCNPs are discussed. Finally, recent examples of applications of UCNPs in biomedical and optoelectronics research, giving our own perspectives on future directions and emerging possibilities of the field are described. PMID:27345736

  19. Pentanuclear lanthanide pyramids based on thiacalix[4]arene ligand exhibiting slow magnetic relaxation.

    PubMed

    Ge, Jing-Yuan; Ru, Jing; Gao, Feng; Song, You; Zhou, Xin-Hui; Zuo, Jing-Lin

    2015-09-21

    A series of pentanuclear Ln(III) clusters, [Ln5(μ4-OH)(μ3-OH)4(L1)(acac)6] (H4L1 = p-tert-butylthiacalix[4]arene; acac = acetylacetonate; Ln = Dy, Ho, Er) and [Ln5(μ5-OH)(μ3-OH)4(L1)(L2)2(acac)2(CH3OH)2] (H3L2 = 5,11,17,23-tetrakis(1,1-dimethylethyl)-25,26,27-trihydroxy-28-methoxy thiacalix[4]arene; Ln = Dy, Ho, Er), have been synthesized based on the thiacalix[4]arene ligand. All of these complexes feature a square-based pyramid with four triangular Ln3 structural motifs. One μ4-OH group bridges four Ln(III) ions in the basal plane of , while the OH group in complexes adopts the μ5-coordination mode. Our results illuminate the coordination modes of the versatile thiacalix[4]arene ligands and their application to new cluster compounds. The structural and magnetic studies confirm that the molecular symmetries and coordination geometries for lanthanide metal cores have a significant effect on some parameters as single-molecule magnets. Among them, two Dy5 pyramids exhibit distinct slow magnetic relaxation. PMID:26237158

  20. Multifunctional lanthanide-organic frameworks for fluorescent sensing, gas separation and catalysis.

    PubMed

    Liu, Xiaobin; Lin, Huan; Xiao, Zhenyu; Fan, Weidong; Huang, Ao; Wang, Rongming; Zhang, Liangliang; Sun, Daofeng

    2016-03-01

    Two lanthanide MOFs based on 3,3'-((2,3,6,7-tetramethoxyanthracene-9,10-diyl)bis(4,1-phenylene))diacrylic acid (H2LOMe), [Eu(LOMe)1.5(H2O)2]·3.5DMA·2H2O (1) and [Pr(LOMe)(H2O)4]·2.5DMA·3H2O (2) were synthesized under solvothermal conditions. Complex 1 displayed a 2D net with single nodal 44-sql topology, which further formed a 3D supramolecular architecture by strong π⋯π interaction. Complex 2 featured a 3D open framework with {42·84}-PtS topology. The PL spectrum results showed that 2 has potential application not only in the sensing of small organic molecules, such as DMF and NB, but also in detecting Al3+ and nitroaromatic derivatives. Furthermore, 2 also showed the selective adsorption of CO2 over CH4 and high catalytic activities with the cyanosilylation reaction. PMID:26815197

  1. Self-assembled light lanthanide oxalate architecture with controlled morphology, characterization, growing mechanism and optical property

    SciTech Connect

    He, Hongmei; Zhang, Youjin; Zhu, Wei; Zheng, Ao

    2011-10-15

    Highlights: {yields} Flower-like Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O was gained with Na{sub 3}Cit assisted precipitation method. {yields} The mechanism of the flower-like Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O formation was proposed. {yields} The Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O and Sm{sub 2}O{sub 3} samples exhibited obviously different PL spectra. {yields} Ln{sub 2}(C{sub 2}O{sub 4}){sub 3}.nH{sub 2}O (Ln = Gd, Dy, Lu, Y) also were achieved by the simple method. -- Abstract: Flower-like Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O had been synthesized by a facile complex agent assisted precipitation method. The flower-like Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O was characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, thermogravimetry-differential thermal analysis and photoluminescence. The possible growth mechanism of the flower-like Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O was proposed. To extend this method, other Ln{sub 2}(C{sub 2}O{sub 4}){sub 3}.nH{sub 2}O (Ln = Gd, Dy, Lu, Y) with different morphologies also had been prepared by adjusting different rare earth precursors. Further studies revealed that besides the reaction conditions and the additive amount of complex agents, the morphologies of the as-synthesised lanthanide oxalates were also determined by the rare earth ions. The Sm{sub 2}(C{sub 2}O{sub 4}){sub 3}.10H{sub 2}O and Sm{sub 2}O{sub 3} samples exhibited different photoluminescence spectra, which was relevant to Sm{sup 3+} energy level structure of 4f electrons. The method may be applied in the synthesis of other lanthanide compounds, and the work could explore the potential optical materials.

  2. Synthesis, structures, and photoluminescence properties of novel lanthanide tetracyanoplatinates lacking Pt-Pt interactions

    SciTech Connect

    Stojanovic, Milorad; Robinson, Nicholas J.; Chen Xi; Smith, Philip A.; Sykora, Richard E.

    2010-04-15

    The synthesis of a series of lanthanide tetracyanoplatinates all incorporating 2,2':6',2''-terpyridine (terpy) have been carried out by reaction of Ln{sup 3+} nitrate salts with terpy and potassium tetracyanoplatinate. The incorporation of different Ln{sup 3+} cations results in the isolation of [Ln(DMF){sub 2}(C{sub 15}H{sub 11}N{sub 3})(H{sub 2}O){sub 2}(NO{sub 3})]Pt(CN){sub 4} (Ln=La-Nd, Sm-Yb) under otherwise identical reaction conditions. These compounds have been isolated as single crystals and X-ray diffraction has been used to investigate their structural features. All of the reported compounds are isostructural. Crystallographic data for the representative Eu{sup 3+} compound (EuPt) are (MoKalpha, lambda=0.71073 A): monoclinic, space group P2{sub 1}/c, a=10.1234(4) A, b=18.7060(7) A, c=17.1642(5) A, beta=97.249(3){sup o}, V=3224.4(2), Z=4, R(F)=2.78% for 426 parameters with 7724 reflections with I>2sigma(I). The structure consists of a zero-dimensional, ionic salt containing complex [Eu(DMF){sub 2}(C{sub 15}H{sub 11}N{sub 3})(H{sub 2}O){sub 2}(NO{sub 3})]{sup 2+} cations and Pt(CN){sub 4}{sup 2-} anions. The complex cations contain the Eu{sup 3+} ions in a tri-capped trigonal prismatic coordination environment with one terdentate 2,2':6',2''-terpyridine molecule, one bidentate nitrate anion, two O-bound dimethylformamide molecules, and two coordinated water molecules. Photoluminescence data illustrate that EuPt displays intramolecular energy transfer from the coordinated terpy molecule to the Eu{sup 3+} cation. The uncoordinated tetracyanoplatinate anion also exhibits visible emission. - Graphical abstract: The synthesis of an isostructural series of lanthanide tetracyanoplatinates incorporating 2,2':6',2''-terpyridine are presented. Solid-state absorption and luminescence properties are discussed for the Eu{sup 3+} and La{sup 3+} compounds.

  3. Magneto-photoluminescence in lanthanide-bearing endohedral metallofullerenes with various cage symmetries

    NASA Astrophysics Data System (ADS)

    Merritt, Travis; Dorn, Harry; Khodaparast, Giti A.; McGill, Steve

    2012-02-01

    Taken as a family, endohedral metallofullerenes (EMF) nanomaterials provide opportunities for exquisite functional tunability at the nanoscale, enabling a wide range of synthetic nanoparticles with diverse sizes, symmetries, electronic, optical and, especially, magnetic properties. In particular, metallofullerenes incarcerating lanthanide ions will permit endohedral luminescence due to the 4f optically-active electrons being uninvolved in the stabilizing charge transfer between the endohedral guest and cage. In addition, if those lanthanide ions possess optical transitions beyond the absorption onset of the cage, a well-defined optical spectrum may be observed for the metallofullerene system. In this talk, several magneto-optical and time-resolved studies at high magnetic fields on lanthanide-based EMFs with different cage symmetries will be presented, where the residual magnetic degeneracies in the lanthanide ion energy levels are lifted and observed in the optical spectrum with magnetic field strengths in excess of 10 T.

  4. Patterns in the stability of the lower oxidation states of the actinides and lanthanides

    SciTech Connect

    Mikheev, N.B.; Auerman, L.N.; Ionova, G.V.; Korshunov, B.G.; Spitsyn, V.I.

    1986-09-01

    The authors compare the first half of the lanthanides and the second half of the actinides by considering the specifics of the electronic structure of the valence atoms of the f-, d-, and s-orbitals, consisting of he following: The lanthanides from praseodymium to europium and from dysprosium to ytterbium, as well as the actinides from californium to nobelium, have the same electronic configuration f /SUP n/ s/sub 2/ in the state of free neutral atoms, which corresponds to their divalent state. On the basis of a consideration of the energy characteristics of the valence orbitals of the elements of the lanthanide and actinide famililies and as a result of an experimental determination of the standard oxidation potential of these elements, the authors consider the profound similarity between the elements of the first half of the lanthanide family and the second half of the actinide family to be established.

  5. Lanthanide salts solutions: representation of osmotic coefficients within the binding mean spherical approximation.

    PubMed

    Ruas, Alexandre; Moisy, Philippe; Simonin, Jean-Pierre; Bernard, Olivier; Dufrêche, Jean-François; Turq, Pierre

    2005-03-24

    Osmotic coefficients of aqueous solutions of lanthanide salts are described using the binding mean spherical approximation (BIMSA) model based on the Wertheim formalism for association. The lanthanide(III) cation and the co-ion are allowed to form a 1-1 ion pair. Hydration is taken into account by introducing concentration-dependent cation size and solution permittivity. An expression for the osmotic coefficient, derived within the BIMSA, is used to fit data for a wide variety of lanthanide pure salt aqueous solutions at 25 degrees C. A total of 38 lanthanide salts have been treated, including perchlorates, nitrates, and chlorides. For most solutions, good fits could be obtained up to high ionic strengths. The relevance of the fitted parameters has been discussed, and a comparison with literature values has been made (especially the association constants) when available.

  6. The TRUSPEAK Concept: Combining CMPO and HDEHP for Separating Trivalent Lanthanides from the Transuranic Elements

    SciTech Connect

    Lumetta, Gregg J.; Gelis, Artem V.; Braley, Jenifer C.; Carter, Jennifer C.; Pittman, Jonathan W.; Warner, Marvin G.; Vandegrift, George F.

    2013-04-08

    Combining octyl(phenyl)-N,N-diisobutyl-carbamoylmethyl-phosphine oxide (CMPO) and bis-(2-ethylhexyl) phosphoric acid (HDEHP) into a single process solvent for separating transuranic elements from liquid high-level waste is explored. Co-extraction of americium and the lanthanide elements from nitric acid solution is possible with a solvent mixture consisting of 0.1-M CMPO plus 1-M HDEHP in n-dodecane. Switching the aqueous-phase chemistry to a citrate-buffered solution of diethylene triamine pentaacetic acid (DTPA) allows for selective stripping of americium, separating it from the lanthanide elements. Potential strategies for managing molybdenum and zirconium (both of which co-extract with americium and the lanthanides) have been developed. The work presented here demonstrates the feasibility of combining CMPO and HDEHP into a single extraction solvent for recovering americium from high-level waste and its separation from the lanthanides.

  7. Lanthanide-Directed Fabrication of Four Tetranuclear Quadruple Stranded Helicates Showing Magnetic Refrigeration and Slow Magnetic Relaxation.

    PubMed

    Mondal, Amit Kumar; Jena, Himanshu Sekhar; Malviya, Amita; Konar, Sanjit

    2016-06-01

    A rare class of four tetranuclear lanthanide based quadruple stranded helicates namely, [Ln4L4(OH)2](OAc)2·xH2O (Ln = Gd(III)(1), Dy(III)(2) and x = 4, 5 respectively), [Er4L4(OH)2](NO3)2·9H2O (3), and [Dy4L4(NO3)](NO3)2·2CH3OH·H2O (4) were synthesized by employing succinohydrazone derived bis-tridentate ligand (H2L) and characterized. Structures of 1-3 are similar to each other except the nature of counterions and number of lattice water molecules. In 4, a distorted nitrate ion was arranged in a hexagonal manner holding four dysprosium centers in a slightly twisted manner. Because of the symmetrical nature of each complex, the C4 axis crosses the center of helicate resulting a pseudo-D4 coordination environment. Each ligand coordinates to lanthanide centers in helical manner forming mixture of left (Λ) and right (Δ) handed discrete units. Complex 1 exhibits antiferromagnetic exchange interaction between nearby Gd(III) centers and shows magnetic refrigeration (-ΔSm = 24.4 J kg(-1) K(-1) for ΔH = 7 T at 3 K). AC magnetic susceptibility measurements of 2 and 4 demonstrate slow relaxation behavior, with Ueff (effective energy barrier) of 20.5 and 4.6 K, respectively. As per our knowledge, complexes 1, 2, and 4 represent the first examples of aesthetically pleasing quadruple stranded helicates showing potential magnetocaloric effect and single-molecule-magnet-like behavior. PMID:27196362

  8. SEPARATION OF EUROPIUM FROM OTHER LANTHANIDE RAE EARTHS BY SOLVENT EXTRACTION

    DOEpatents

    Peppard, D.F.; Horwitz, E.P.; Mason, G.W.

    1963-02-12

    This patent deals with a process of separating europium from other lanthanides present in aqueous hydrochloric or sulfuric acid solutions. The europium is selectively reduced to the divalent state with a divalent chromium salt formed in situ from chromium(III) salt plus zinc amalgam. The other trivalent lanthanides are then extracted away from the divalent europium with a nitrogen-flushed phosphoric acid ester or a phosphonic acid ester. (AEC)

  9. Gold Coated Lanthanide Phosphate Nanoparticles for Targeted Alpha Generator Radiotherapy

    SciTech Connect

    McLaughlin, Mark F; Woodward, Jonathan; Boll, Rose Ann; Wall, Jonathan; Rondinone, Adam Justin; Kennel, Steve J; Mirzadeh, Saed; Robertson, David J.

    2013-01-01

    Targeted radiotherapies maximize cytotoxicty to cancer cells. In vivo generators such as 225Ac, which emits four particles in its decay chain, can significantly amplify the radiation dose delivered to the target site. However, renal dose from unbound 213Bi escaping during the decay process limits the dose of 225Ac that can be administered. Traditional chelating moieties are unable to sequester the radioactive daughters because of the high recoil energy from alpha particle emission. To counter this, we demonstrate that an engineered multilayered nanoparticle-antibody conjugate can both deliver radiation and contain the decay daughters of the in vivo -generator 225Ac while targeting biologically relevant receptors. These multi-shell nanoparticles combine the radiation resistance of crystalline lanthanide phosphate to encapsulate and contain 225Ac and its radioactive decay daughters, the magnetic properties of gadolinium phosphate for easy separation, and established surface chemistry of gold for attachment of nanoparticles to targeting antibodies.

  10. Multimodal cancer imaging using lanthanide-based upconversion nanoparticles.

    PubMed

    Yang, Dongmei; Li, Chunxia; Lin, Jun

    2015-01-01

    Multimodal nanoprobes that integrate different imaging modalities in one nano-system could offer synergistic effect over any modality alone to satisfy the higher requirements on the efficiency and accuracy for clinical diagnosis and medical research. Upconversion nanoparticles (UCNPs), particularly lanthanide (Ln)-based NPs have been regarded as an ideal building block for constructing multimodal bioprobes due to their fascinating properties. In this review, we first summarize recent advances in the optimizations of existing UCNPs. In particular, we highlight the applications of Ln-based UCNPs for multimodal cancer imaging in vitro and in vivo. The explorations of UCNPs-based multimodal nanoprobes for targeting diagnosis and imaging-guided therapeutics are also presented. Finally, the challenges and perspectives of Ln-based UCNPs in this rapid growing field are discussed. PMID:26293416

  11. Lanthanide transport in stabilized zirconias: interrelation between ionic radius and diffusion coefficient.

    PubMed

    Kilo, Martin; Taylor, Marcela A; Argirusis, Christos; Borchardt, Günter; Weber, Sylvain; Scherrer, Hubert; Jackson, Robert A

    2004-09-15

    The diffusion of all stable lanthanides was measured both in calcia stabilized zirconia (CSZ) and in yttria stabilized zirconia (YSZ) in the temperature range between 1,286 and 1,600 degrees C. The lanthanide diffusion coefficients obtained increase with increasing ionic radius. The experimental activation enthalpy of diffusion is near 6 eV for CSZ and between 4 and 5 eV for YSZ and is not strongly affected by the type of lanthanide. The results were correlated with defect energy calculations of the lanthanide diffusion enthalpy using the Mott-Littleton approach. An association enthalpy of cation vacancies with oxygen vacancies of about 1 eV (96 kJ/mol) was deduced in the case of CSZ, while there is no association in the case of YSZ. Furthermore, the change in diffusion coefficients can be correlated to the interaction parameter for the interaction between the lanthanide oxide with zirconia: The higher the interaction parameter, the higher the lanthanide diffusion coefficient.

  12. Lanthanide transport in stabilized zirconias: Interrelation between ionic radius and diffusion coefficient

    NASA Astrophysics Data System (ADS)

    Kilo, Martin; Taylor, Marcela A.; Argirusis, Christos; Borchardt, Günter; Weber, Sylvain; Scherrer, Hubert; Jackson, Robert A.

    2004-09-01

    The diffusion of all stable lanthanides was measured both in calcia stabilized zirconia (CSZ) and in yttria stabilized zirconia (YSZ) in the temperature range between 1286 and 1600 °C. The lanthanide diffusion coefficients obtained increase with increasing ionic radius. The experimental activation enthalpy of diffusion is near 6 eV for CSZ and between 4 and 5 eV for YSZ and is not strongly affected by the type of lanthanide. The results were correlated with defect energy calculations of the lanthanide diffusion enthalpy using the Mott-Littleton approach. An association enthalpy of cation vacancies with oxygen vacancies of about 1 eV (96 kJ/mol) was deduced in the case of CSZ, while there is no association in the case of YSZ. Furthermore, the change in diffusion coefficients can be correlated to the interaction parameter for the interaction between the lanthanide oxide with zirconia: The higher the interaction parameter, the higher the lanthanide diffusion coefficient.

  13. Interaction between lanthanide ions and Saccharomyces cerevisiae cells.

    PubMed

    Ene, Cristian D; Ruta, Lavinia L; Nicolau, Ioana; Popa, Claudia V; Iordache, Virgil; Neagoe, Aurora D; Farcasanu, Ileana C

    2015-10-01

    Lanthanides are a group of non-essential elements with important imaging and therapeutic applications. Although trivalent lanthanide ions (Ln³⁺) are used as potent blockers of Ca²⁺ channels, the systematic studies correlating Ln³⁺ accumulation and toxicity to Ca²⁺ channel blocking activity are scarce. In this study, we made use of the eukaryotic model Saccharomyces cerevisiae to investigate the correlation between Ln³⁺ accumulation, their toxicity and their capacity to block the exogenous stress-induced Ca²⁺ influx into the cytosol. It was found that the Ln³⁺ blocked the Ca²⁺ entry into the yeast cells only when present at concentration high enough to allow rapid binding to cell surface. At lower concentrations, Ln³⁺ were taken up by the cell, but Ca²⁺ blockage was no longer achieved. At 1 mM concentration, all ions from the Ln³⁺ series could block Ca²⁺ entry into cytosol with the exception of La³⁺, and to a lesser extent, Pr³⁺ and Nd³⁺. The plasma membrane Ca²⁺-channel Cch1/Mid1 contributed to La³⁺ and Gd³⁺ entry into the cells, with a significant preference for La³⁺. The results open the possibility to obtain cells loaded with controlled amounts and ratios of Ln³⁺.

  14. X-ray spectral diagnostics of synthetic lanthanide silicates

    NASA Astrophysics Data System (ADS)

    Kravtsova, A. N.; Guda, A. A.; Soldatov, A. V.; Goettlicher, J.; Taroev, V. K.; Kashaev, A. A.; Suvorova, L. F.; Tauson, V. L.

    2015-12-01

    Potassium and rare-earth (Eu, Sm, Yb, Ce) silicate and aluminosilicate crystals are hydrothermally synthesized under isothermal conditions at 500°C and a pressure of 100 MPa. The chemical and structural formulas of the synthesized compounds HK6Eu[Si10O25], K7Sm3[Si12O32], K2Sm[AlSi4O12] · 0.375H2O, K4Yb2[Si8O21], and K4Ce2[Al2Si8O24] are determined. In addition, a synthesis product with Eu, in which the dominant phase is assumed to be K3Eu3+[Si6O15] · 2H2O, is studied. The oxidation state of lanthanides in the silicates under study is determined based on X-ray absorption near-edge structure spectroscopy. The Eu L 3-, Sm L 3-, Yb L 3-, and Ce L 3-edge X-ray absorption spectra of the studied silicates and reference samples are recorded using a Rigaku R-XAS laboratory spectrometer. As reference samples, Eu2+S, Eu3+F3, Eu 2 3+ O3, Sm 2 3+ O3, Yb 2 3+ O3, Yb3+F3, Yb3+Cl3, Ce 2 3+ O3, and Ce4+O2 are used. Comparison of the absorption edge energies of lanthanide silicates and reference samples shows that Eu, Sm, Yb, and Ce in all the samples studied are in the oxidation state 3+. The synthesized silicates will supplement our knowledge of possible rare-earth minerals existing in hydrothermal systems, which is important for analyzing the distribution spectra of rare elements, which are widely used for diagnostics of geochemical processes and determination of sources of ore materials.

  15. Syntheses, structures and tunable luminescence of lanthanide metal-organic frameworks based on azole-containing carboxylic acid ligand

    NASA Astrophysics Data System (ADS)

    Zhao, Dian; Rao, Xingtang; Yu, Jiancan; Cui, Yuanjing; Yang, Yu; Qian, Guodong

    2015-10-01

    Design and synthesis of a series of isostructural lanthanide metal-organic frameworks (LnMOFs) serving as phosphors by coordinate the H2TIPA (5-(1H-tetrazol-5-yl)isophthalic acid) ligands and lanthanide ions is reported. The color of the luminescence can be tuned by adjusting the relative concentration of the lanthanide ions in the host framework GdTIPA, and near-pure-white light emission can be achieved.

  16. Dissolution of metal oxides and separation of uranium from lanthanides and actinides in supercritical carbon dioxide

    SciTech Connect

    Quach, D.L.; Wai, C.M.; Mincher, B.J.

    2013-07-01

    This paper investigates the feasibility of extracting and separating uranium from lanthanides and other actinides by using supercritical fluid carbon dioxide (sc-CO{sub 2}) as a solvent modified with tri-n-butylphosphate (TBP) for the development of a counter current stripping technique, which would be a more efficient and environmentally benign technology for spent nuclear fuel reprocessing compared to traditional solvent extraction. Several actinides (U, Pu, and Np) and europium were extracted in sc-CO{sub 2} modified with TBP over a range of nitric acid concentrations and then the actinides were exposed to reducing and complexing agents to suppress their extractability. According to this study, uranium/europium and uranium/plutonium extraction and separation in sc-CO{sub 2} modified with TBP is successful at nitric acid concentrations of less than 6 M and at nitric acid concentrations of less than 3 M with acetohydroxamic acid or oxalic acid, respectively. A scheme for recycling uranium from spent nuclear fuel by using sc-CO{sub 2} and counter current stripping columns is presented. (authors)

  17. Two novel 2D lanthanide sulfate frameworks: Syntheses, structures, and luminescence properties

    NASA Astrophysics Data System (ADS)

    Li, Zhong-Yi; Zhang, Chi; Zhang, Fu-Li; Zhang, Fu-Qiang; Zhang, Xiang-Fei; Li, Su-Zhi; Cao, Guang-Xiu; Zhai, Bin

    2016-03-01

    Two novel lanthanide-sulfate compounds, [Ln2(SO4)3(H2O)8] (Ln = Tb (1) and Dy (2)), have been synthesized under hydrothermal reactions. X-ray crystal structure analyses reveal that 1 and 2 are isomorphous and crystallize in monoclinic C2/c pace group, showing a layered structure. The layers bear a rare quasi-honeycomb metal arrangement, which is fastened by μ3 = η1:η1:η1 and μ2 = η1:η1 sulfates. If assigning the μ3 = η1:η1:η1 sulfate as a 3-connected node and the Ln3+ ion as a 4-connected node, the network can be rationalized as a binodal (3,4)-connected V2O5 topology with a Schäfli symbol of (42·63·8) (42·6). In addition, the infrared, thermogravimetric analysis and luminescent properties were also studied. Complexes 1 and 2 exhibit outstanding thermal stability and characteristic terbium and dysprosium luminescence.

  18. Bioadsorption of rare earth elements through cell surface display of lanthanide binding tags

    DOE PAGES

    Park, Dan M.; Reed, David W.; Yung, Mimi C.; Eslamimanesh, Ali; Lencka, Malgorzata M.; Anderko, Andrzej; Fujita, Yoshiko; Riman, Richard E.; Navrotsky, Alexandra; Jiao, Yongqin

    2016-02-02

    In this study, with the increasing demand for rare earth elements (REEs) in many emerging clean energy technologies, there is an urgent need for the development of new approaches for efficient REE extraction and recovery. As a step toward this goal, we genetically engineered the aerobic bacterium Caulobacter crescentus for REE adsorption through high-density cell surface display of lanthanide binding tags (LBTs) on its S-layer. The LBT-displayed strains exhibited enhanced adsorption of REEs compared to cells lacking LBT, high specificity for REEs, and an adsorption preference for REEs with small atomic radii. Adsorbed Tb3+ could be effectively recovered using citrate,more » consistent with thermodynamic speciation calculations that predicted strong complexation of Tb3+ by citrate. No reduction in Tb3+ adsorption capacity was observed following citrate elution, enabling consecutive adsorption/desorption cycles. The LBT-displayed strain was effective for extracting REEs from the acid leachate of core samples collected at a prospective rare earth mine. Our collective results demonstrate a rapid, efficient, and reversible process for REE adsorption with potential industrial application for REE enrichment and separation.« less

  19. Dissolution of cerium(IV)-lanthanide(III) oxides: comparative effect of chemical composition, temperature, and acidity.

    PubMed

    Horlait, D; Clavier, N; Szenknect, S; Dacheux, N; Dubois, V

    2012-03-19

    The dissolution of Ce(1-x)Ln(x)O(2-x/2) solid solutions was undertaken in various acid media in order to evaluate the effects of several physicochemical parameters such as chemical composition, temperature, and acidity on the reaction kinetics. The normalized dissolution rates (R(L,0)) were found to be strongly modified by the trivalent lanthanide incorporation rate, due to the presence of oxygen vacancies decreasing the samples cohesion. Conversely, the nature of the trivalent cation considered only weakly impacted the R(L,0) values. The dependence of the normalized dissolution rates on the temperature then appeared to be of the same order of magnitude than that of chemical composition. Moreover, it allowed determining the corresponding activation energy (E(A) ≈ 60-85 kJ·mol(-1)) which accounts for a dissolution driven by surface-controlled reactions. A similar conclusion was made regarding the acidity of the solution: the partial order related to (H(3)O(+)) reaching about 0.7. Finally, the prevailing effect of the incorporation of aliovalent cations in the fluorite-type CeO(2) matrix on the dissolution kinetics precluded the observation of slight effects such as those linked to the complexing agents or to the crystal structure of the samples.

  20. Redox-activated MRI contrast agents based on lanthanide and transition metal ions.

    PubMed

    Tsitovich, Pavel B; Burns, Patrick J; McKay, Adam M; Morrow, Janet R

    2014-04-01

    The reduction/oxidation (redox) potential of tissue is tightly regulated in order to maintain normal physiological processes, but is disrupted in disease states. Thus, the development of new tools to map tissue redox potential may be clinically important for the diagnosis of diseases that lead to redox imbalances. One promising area of chemical research is the development of redox-activated probes for mapping tissue through magnetic resonance imaging (MRI). In this review, we summarize several strategies for the design of redox-responsive MRI contrast agents. Our emphasis is on both lanthanide(III) and transition metal(II/III) ion complexes that provide contrast either as T1 relaxivity MRI contrast agents or as paramagnetic chemical exchange saturation transfer (PARACEST) contrast agents. These agents are redox-triggered by a variety of chemical reactions or switches including redox-activated thiol groups, and heterocyclic groups that interact with the metal ion or influence properties of other ancillary ligands. Metal ion centered redox is an approach which is ripe for development by coordination chemists. Redox-triggered metal ion approaches have great potential for creating large differences in magnetic properties that lead to changes in contrast. An attractive feature of these agents is the ease of fine-tuning the metal ion redox potential over a biologically relevant range.