Trivalent Praseodymium Research Articles

Electron transfer dissociation mass spectrometry of acidic phosphorylated peptides cationized with trivalent praseodymium.

The lanthanide ion praseodymium, Pr(III), was employed to study metallated ion formation and electron transfer dissociation (ETD) of 27 biological and model highly acidic phosphopeptides. All phosphopeptides investigated form metallated ions by electrospray ionization (ESI) that can be studied by ETD to yield abundant sequence information. The ions formed are [M+Pr-H]2+ , [M+Pr]3+ , and [M+Pr+H]4+ . All biological phosphopeptides with a chain length of seven or more residues generate [M+Pr]3+ . For biological phosphopeptides, [M+Pr]3+ undergoes more backbone cleavage by ETD than [M+Pr - H]2+ and, in some cases, full sequence coverage occurs. Acidic model phosphorylated hexa-peptides and octa-peptides, composed of alanine residues and one phosphorylated residue, form exclusively [M+Pr - H]2+ by ESI. Limited sequence information is obtained by ETD of [M+Pr - H]2+ with only metallated product ions being generated. For two biological phosphopeptides, [M+Pr+H]4+ is observed and may be due to the presence of at least one residue with a highly basic side chain that facilitates the addition of an extra proton. For the model phosphopeptides, more sequence coverage occurs when the phosphorylated residue is in the middle of the sequence than at either the N- or C-terminus. ETD of the metallated precursor ions formed by ESI generates exclusively metallated and nonmetallated c- and z-ions for the biological phosphopeptides, while metallated c-ions, z-ions, and a few y-ions form for the model phosphopeptides. Most of the product ions contain the phosphorylated residue indicating that the metal ion binds predominantly at the deprotonated phosphate group. The results of this study indicate that ETD is a promising tool for sequencing highly acidic phosphorylated peptides by metal adduction with Pr (III) and, by extension, all nonradioactive lanthanide metal ions.

A novel strategy to improve the sensitivity of aerosol phosphor thermometry using co-doped phosphors

A novel strategy is presented to improve the temperature sensitivity and potentially extend the temperature range of aerosol phosphor thermometry (APT) by co-doping host materials with two rare-earth ions. The ratio of the emission bands from each ion are measured and calibrated versus temperature to utilize the high sensitivity of thermographic phosphor absolute signal levels. The potential of the technique is illustrated using trivalent cerium (Ce3+) and praseodymium (Pr3+) co-doped into yttrium aluminum garnet (Ce,Pr:YAG). The measured fractional sensitivity of this phosphor from 300–450 K was 0.004–0.006 K−1, a factor of 1.5–2 better than previously observed for Eu:BAM. Additionally, the single-shot precision (1σ) was between 9 and 25 K over the range of temperatures measured, illustrating the utility of this co-doping strategy. The level of temperature sensitivity and single-shot precision observed here should be achievable over different temperature ranges by doping Ce3+ and Pr3+ into different hosts. This new strategy should provide a pathway to ultimately extend the high-temperature single-shot measurement limit for APT to temperatures greater than 1000 K and push forward the state-of-the-art for planar temperature diagnostics in combustion applications.

Compact Two-Color Pr3+-Doped ZBLAN Fiber Lasers

ABSTRACTTwo-color laser simultaneous oscillation in compact trivalent praseodymium ion (Pr3+)-doped ZrF4-BaF2-LaF3-AlF3-NaF (ZBLAN) fiber lasers is investigated. Fiber pigtails by coating high-reflective visible dielectric films are utilized as fiber mirrors (FMs) to construct compact all-fiber laser cavity. Reflectance/transmittance of FMs is intentionally designed to balance net gains and reduce gain competition of different lasable wavelengths in the constructed fiber lasers. By using two selected FMs with high reflectivity at green-light and low reflectivity at red-light, simultaneous green and red laser emission in all-fiber Pr3+-doped ZBLAN fiber laser is obtained. Moreover, simultaneous orange and red laser emission is also achieved with another selected FM of high reflectivity at orange-light and low reflectivity at red-light. Our work will provide an effective and easy method to construct compact special fiber (e.g.,ZBLAN fiber, chalcogenide fiber) lasers.

Effects of acidic peptide size and sequence on trivalent praseodymium adduction and electron transfer dissociation mass spectrometry.

Using the lanthanide ion praseodymium, Pr(III), metallated ion formation and electron transfer dissociation (ETD) were studied for 25 biological and model acidic peptides. For chain lengths of seven or more residues, even highly acidic peptides that can be difficult to protonate by electrospray ionization will metallate and undergo abundant ETD fragmentation. Peptides composed of predominantly acidic residues form only the deprotonated ion, [M+Pr - H]2+ ; this ion yields near complete ETD sequence coverage for larger peptides. Peptides with a mixture of acidic and neutral residues generate [M+Pr]3+ , which cleaves between every residue for many peptides. Acidic peptides that contain at least one residue with a basic side chain also produce the protonated ion, [M+Pr+H]4+ ; this ion undergoes the most extensive sequence coverage by ETD. Primarily metallated and non-metallated c- and z-ions form for all peptides investigated. Metal adducted product ions are only present when at least half of the peptide sequence can be incorporated into the ion; this suggests that the metal ion simultaneously attaches to more than one acidic site. The only site consistently lacking dissociation is at the N-terminal side of a proline residue. Increasing peptide chain length generates more backbone cleavage for metal-peptide complexes with the same charge state. For acidic peptides with the same length, increasing the precursor ion charge state from 2+ to 3+ also leads to more cleavage. The results of this study indicate that highly acidic peptides can be sequenced by ETD of complexes formed with Pr(III). Copyright © 2017 John Wiley & Sons, Ltd.

Synthesis and thermoluminescence of LaAlO3:Pr3+ to UVC radiation dosimetry

Thermoluminescent (TL) response of trivalent praseodymium ion doped lanthanum aluminate (LaAlO3:Pr3+) obtained by Pechini method and Spray Dryer was studied. TL response of LaAlO3:Pr3+ powders submitted at 1600°C exhibited one peak centered at 157°C. Sensitivity of LaAlO3:Pr3+ was improved in around 90 times compared with undoped LaAlO3. TL response as a function of wavelength showed a maximum in 230nm. Dosimetric characteristics of LaAlO3:Pr3+ under UVR radiation effects were analyzed. Evaluation of activation energy was obtained by Glow Fit v.1.3 software. Experimental results about thermoluminescent characteristics of LaAlO3:Pr3+ suggest as good candidate to be employed as a complementary thermoluminescent device with other TL phosphors as aluminum oxide

Solvation structure and thermodynamics for Pr(III), Nd(III) and Dy(III) complexes in ionic liquids evaluated by Raman spectroscopy and DFT calculation

The coordination states of trivalent praseodymium, neodymium, and dysprosium complexes in the ionic liquid, triethyl-n-pentylphosphonium bis(trifluoromethyl-sulfonyl) amide ([P2225][TFSA]) were investigated by Raman spectroscopy. The effect of the concentration of rare earth ions on the Raman spectra was investigated, ranging from 0.23 to 0.45 mol kg−1 of Pr(III), Nd(III), and Dy(III) in [P2225][TFSA]. Based on a conventional analysis, the solvation numbers, n, of Pr(III), Nd(III), and Dy(III) in [P2225][TFSA] were determined to be 4.99, 5.01, and 5.00 at 298 K and 5.04, 5.06, and 5.07 at 373 K, respectively.Thermodynamic properties such as ΔisoG, ΔisoH, and ΔisoS for the isomerism of [TFSA]− from trans- to cis-coordinated isomer in the bulk and the first solvation sphere of the central RE3+ (RE = Pr, Nd, and Dy) cation in [P2225][TFSA] were evaluated from the temperature dependence of the Raman bands, measured at temperatures ranging from 298 to 398 K. Regarding the bulk properties, ΔisoG(bulk), ΔisoH(bulk), and TΔisoS(bulk) at 298 K were found to be −1.06, 6.86, and 7.92 kJ mol−1, respectively. The trans-[TFSA]− was a dominant contributor to the enthalpy, as shown by the positive value of ΔisoH(bulk). The value of TΔisoS(bulk) was slightly larger than that of ΔisoH(bulk), and cis-[TFSA]− was, therefore, entropy-controlled in [P2225][TFSA]. In contrast, in the first solvation sphere of the RE3+ cation, ΔisoH(RE) became remarkably negative, suggesting that cis-[TFSA]− isomers were stabilized by enthalpic contributions. Furthermore, ΔisoH(RE) contributed to the remarkable decrease in ΔisoG(RE), and this result clearly indicates that cis-[TFSA]− conformers bound to RE3+ cations are the preferred coordination state of [RE(III)(cis-TFSA)5]2− in [P2225][TFSA].Moreover, optimized geometries and binding energies of [Pr(III)(cis-TFSA)5]2−, [Nd(III)(cis-TFSA)5]2−, and [Dy(III)(cis-TFSA)5]2− clusters were also investigated by DFT calculations using the ADF package. The bonding energy, ΔEb, was calculated as ΔEb = Etot(cluster) − Etot(RE3+) − nEtot([TFSA]−), and ΔEb ([Pr(III)(cis-TFSA)5]2−), ΔEb([Nd(III)(cis-TFSA)5]2−), and ΔEb([Dy(III)(cis-TFSA)5]2−) were calculated to be −4238.6 ± 6.8, −4362.3 ± 8.2, and −4284.2 ± 7.4 kJ mol−1, respectively. This series of structural results allows us to conclude that [Dy(III)(cis-TFSA)5]2− clusters are more stable state than the [Pr(III)(cis-TFSA)5]2− clusters in [P2225][TFSA]. Furthermore, the average atomic charges and the bond distances of these clusters were consistent with the thermodynamic properties.

Morphological and Optical Characterizations of CaAl2O4 Doped with Trivalent Praseodymium

This work was synthesized CaAl2O4 (calcium aluminate) doped with trivalent praseodymium ions. CaAl2O4 with praseodymium 1.0% and 0.5% were synthesized. The powders of aluminates were characterized by scanning electron microscopy and luminescence spectrofluorimetry. CaAl2O4 doped with praseodymium ion that showed less porosity in its grain structure and luminescent transitions that are dependent on the wavelengths of excitation and showing both types of transitions both 5d-4f and 4f-4f.

Growth and diode-pumped laser operation of Pr3+:β-(Y0.5,Gd0.5)F3 at various transitions.

We report on the crystal growth of the orthorhombic low-temperature β-phase of (Y0.5,Gd0.5)F3 (YGF) single crystals. The crystals were activated with trivalent praseodymium (Pr3+) and characterized with respect to their ground state absorption and stimulated emission properties. Under InGaN-laser-diode pumping, laser oscillation was obtained at more than ten wavelengths in the green, orange, red, and dark red spectral regions. In these initial experiments, output powers exceeding 100 mW and slope efficiencies between 10% and 30% were obtained. To the best of our knowledge, these results represent the first application of YGF crystals as laser host material for any active ion.

Monochromic orange emission of Pr3+ ions in phosphate glass

Zinc strontium phosphate glasses doped with different trivalent praseodymium ion (Pr3+) concentrations are presented and their photoluminescence properties are investigated upon 442 nm excitation. With the Pr3+ concentration decreasing, the orange emission of Pr3+ (D21 HJ3) is enhanced steadily at the cost of its blue emission (P1,03 H43). Monochromic orange emission of Pr3+ ions is obtained when the Pr3+ doping is reduced to 0.05 mol.%. The mechanism controlling the monochromatic characteristic of Pr3+ emissions is supposed to be associated with the phonon-aided nonradiative relaxation process of Pr3+: Pj3→

Structural variations of praseodymium(III) benzoate derivative complexes with dimethylformamide

Eight- or nine-coordinated trivalent praseodymium complexes derived from para-substituted benzoic acids have been synthesized by the reaction of hydrated Pr(OH)3 with 4-XC6H4CO2H, where X=OMe, H, Cl, NO2, OH, NH2 or F, in dimethylformamide [DMF, (CH3)2NCHO], and eight single crystal X-ray structures have been determined. For the substituted systems studied, dimeric units hydrogen-bonded into chains or networks are observed in complexes comprising electron-donating groups X, whereas electron-withdrawing groups X form polymeric complexes. However, the steric effect of the ligand and the coordination of solvated molecules also play roles in determining the coordination polyhedra. The coordination geometry of the carboxylate ligand in these complexes is restricted to three types: bidentate chelating (η2); bridging bidentate (μ-η1:η1 (O,O′)) and bridging chelating tridentate (μ-η2:η1). Two geometrical isomers, of [Pr(C6H5COO)3(DMF)(H2O)]2, designated as a and b, crystallize in the same monoclinic space group but differ in the arrangement of C6H5COO and DMF ligands in their coordination polyhedra. The packing of isomer a is more efficient than that of b, resulting in a smaller unit-cell volume of about 50Å3.Although functional group fingerprints from the p-substitution moieties are well-identified in the vibrational spectra of the complexes, reasons are provided to explain why the correlation between carboxyl group ligation and spectra cannot be readily made.

The Gallium Intermetallics REPdGa3 (RE=La, Ce, Pr, Nd, Sm, Eu) with SrPdGa3-type Structure

Abstract The gallium-rich intermetallic phases REPdGa3 (RE=La, Ce, Pr, Nd, Sm, Eu) were obtained by arc-melting of the elements and subsequent annealing for crystal growth. The samples were studied by X-ray diffraction on powders and single crystals. The structures of three crystals were refined from X-ray diffractometer data: SrPdGa3 type, Cmcm, a=634.3(1), b=1027.2(1), c=593.5(1) pm, wR=0.0621, 380 F2 values, 20 variables for CePd0:80(4)Ga3:20(4), a=635.9(1), b=1027.5(1), c=592.0(1) pm, wR=0.1035, 457 F2 values, 19 variables for CePdGa3, and a=640.7(1), b=1038.2(1), c=593.7(1) pm, wR=0.0854, 489 F2 values, 19 variables for EuPdGa3. The REPdGa3 gallides are orthorhombic superstructure variants of the aristotype ThCr2Si2. The palladium and gallium atoms build up polyanionic [PdGa3]δ- networks with Pd-Ga and Ga-Ga distances of 248 - 254 and 266 - 297 pm, respectively, in EuPdGa3. The rare earth atoms fill cavities within the polyanionic networks. They are coordinated by five palladium and twelve gallium atoms. Taking CePdGa3 as an illustrative representative, the band structure calculations show largely dispersive itinerant s, p bands and little dispersive d (Pd) and f (Ce) bands, the latter crossing the Fermi level at large magnitude leading to magnetic instability in a spin-degenerate state and a subsequent antiferromagnetic ground state with a small moment of ±0.36 μB on Ce. The bonding characteristics indicate a prevailing Ce-Ga bonding versus Pd-Ga and Ce-Pd. Temperature-dependent magnetic susceptibility and 151Eu Mössbauer spectroscopic measurements point to stable trivalent lanthanum, cerium, praseodymium, and neodymium, but divalent europium. SmPdGa3 shows intermediate valence. Antiferromagnetic ordering occurs at TN =5.1(5), 7.0(5), 6.3(5), 11.9(5), and 23.0(5) for RE=Ce, Pr, Nd, Sm, and Eu, respectively.

Synthesis and characterization of Y2O3:Pr3+ phosphor powders by simple solvent evaporation

The synthesis of trivalent praseodymium doped yttrium oxide powders (Y2O3:Pr3+) by the solvent evaporation method as well as their structural and luminescent (cathodoluminescence and photoluminescence) properties are reported as a function of the concentration of the reagents and annealing temperatures in the 400 to 1100°C range. These powders become polycrystalline in a cubic Y2O3 structure at temperatures above 600°C. An increase in the diffraction peaks intensity was observed as the temperature is increased. Transmission electron microscopy analysis showed irregular needle like crystallites and the characteristic electron diffraction rings for polycrystalline powders on samples annealing above 600°C. Scanning electron microscopy showed that these crystallites clump into larger particles of irregular shape. Luminescence spectra show the characteristic peaks at 620 and 630nm due to 1D2 to 3H4 transitions in Pr3+ ions in the Y2O3 host.

Luminescence characteristics of doubly doped KLuS2:Eu, RE (RE = Pr, Sm, Ce)

KLuS2 single crystals doped with divalent europium and co-doped with trivalent praseodymium, samarium or cerium were synthesized in the form of crystalline hexagonal platelets as interesting candidates for white LED solid state lighting. Luminescence characteristics in UV/Vis, including radioluminescence, photoluminescence excitation and emission spectra and photoluminescence decays, were measured in the broad concentration and temperature interval revealing presence of thermally stable emission features of both Eu2+ and co-dopants in a single KLuS2 host. Energy transfer from Eu2+ to Pr3+, Sm3+ and Ce3+ is identified. CIE xy-coordinates are used to compare effects of dopants on resulting spectrum. The application potential in white LEDs phosphors is discussed.

Electronic States of Trivalent Praseodymium Ion Doped in 20Al(PO3)3–80LiF Glass

We investigate the photoluminescence (PL) and photoluminescence excitation (PLE) spectra of 20Al(PO3)3–80LiF+Pr glass (APLF+Pr) and Pr3+-doped LiCaAlF6 crystal (Pr:LiCAF) in order to determine the electronic states of Pr3+ in APLF glass host and to improve APLF+Pr scintillation properties. Ultraviolet (UV) emission bands at around 250 and 340 nm were observed from both materials and these can be ascribed to 4f5d→4f2 transitions in Pr3+. Emission at around 400 nm was also obtained and is principally attributed to 1S0→4f2 transition. Difference in the emission profiles of these two materials was found to be due to the extent of the 5d band and its position relative to the 1S0 state. Increasing the concentration of Pr3+ up to 2 mol % was found to improve UV emission ratio due to the faster cross-relaxation of 4f states. This could improve the quantum efficiency of APLF+Pr as a neutron scintillator for scattered-neutron diagnostics in laser fusion research.

Growth, optical spectroscopy and Judd–Ofelt analysis of Pr-doped BaY2F8 monocrystals

This work is devoted to the study of BaY2F8 crystal, doped with different concentrations of trivalent praseodymium ion in the range from 0.3% to 3%. Spectroscopic properties of these materials showed a large dependence on two parameters: dopant concentration and temperature. Judd–Ofelt model analysis of absorption and emission spectra revealed the potential of our materials as promising blue laser emitters.

Liquid–liquid extraction of neodymium(iii) by dialkylphosphate ionic liquids from acidic medium: the importance of the ionic liquid cation

The ionic liquids 1-hexyl-3-methylimidazolium bis(2-ethylhexyl)phosphate, [C6mim][DEHP], 1-hexyl-1-methylpyrrolidinium bis(2-ethylhexyl)phosphate, [C6mpyr][DEHP], and tetrabutylammonium bis(2-ethylhexyl)phosphate, [N4444][DEHP], were prepared and characterized using (1)H and (13)C NMR spectroscopy. The extraction behavior of neodymium(iii) from nitrate medium by these ionic liquids, diluted with the room temperature ionic liquids 1-hexyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide, [C6mim][NTf2], 1-hexyl-3-methylpyrrolidinium bis(trifluoromethylsulfonyl)imide, [C6mpyr][NTf2], and tributylmethylammonium bis(trifluoromethylsulfonyl)imide, [N1444][NTf2], was studied. The distribution ratio of neodymium(iii) was measured as a function of various parameters, such as pH, concentration of the ionic liquid extractant, nature of diluents, concentration of ionic liquid cations and nitrate anions in the aqueous phase. The extraction behavior was compared with that obtained for a solution of the molecular extractant bis(2-ethylhexyl)phosphoric acid (DEHPA) in an ionic liquid diluent. The extraction of neodymium(iii) in the ionic liquids [C6mim][DEHP] and [C6mpyr][DEHP] showed markedly different extraction properties in comparison with that of the quaternary ammonium analogue [N4444][DEHP], especially concerning the pH dependence of the extraction process. These results show that the extraction process can be tuned by the selection of the ionic liquid cation. The extraction experiments also included the trivalent rare-earth ions lanthanum(iii), cerium(iii), praseodymium(iii), ytterbium(iii) and yttrium(iii). Studies of the stripping behavior and the reusability of the ionic liquids were carried out, which indicate that the ionic liquids can be reused with no loss in activity.

Pr:YAG temperature imaging in gas-phase flows

In this study, a new thermographic phosphor for planar gas-phase thermometry is investigated. The thermographic phosphor used is composed of trivalent praseodymium (Pr3+) ions doped into a yttrium aluminum garnet (YAG) host. Spectrally-resolved emission data were taken in a furnace for temperatures up to 1,300 K. The emission spectra were used to develop a temperature measurement strategy utilizing a non-equilibrium population ratio. The developed temperature measurement technique was demonstrated in a turbulent heated air jet for exit temperatures ranging from 300 to 750 K. The results demonstrate the promise of the Pr:YAG phosphor for obtaining high-precision single-shot temperature measurements in gas-phase flows.

Trivalent Cerium and Praseodymium Aromatic Ketone Adducts

AbstractThe reactions of the aromatic ketones benzophenone and 9‐fluorenone with trivalent [LnL3] complexes [Ln = Ce, Pr; L = N(SiMe3)2, C5H5 (Cp)] produce highly colored solutions in toluene. Characterization of these complexes by X‐ray diffraction revealed them to be monoadducts of the form [LnL3(ketone)]. The crystallographically determined C–O bonds of these complexes are longer than those of the free ketones. Significant ligand‐to‐metal charge transfer is also indicated by the ν(C=O) vibration of the coordinated ketone, which appears at lower wavelength. Solution‐based 1H NMR spectroscopy showed paramagnetic spectra of complexes Ln[N(SiMe3)2]3(ketone) and Ln(C5H5)3(ketone), which further supports this finding.

Praseodymium valence determination in Lu2SiO5, Y2SiO5, and Lu3Al5O12 scintillators by x-ray absorption spectroscopy

Until now, determination of both Pr3+ and Pr4+ at the low concentration levels commonly used in single crystal scintillators has proven to be difficult. We have found that it is possible to use synchrotron radiation and superconducting tunnel junction detectors to measure the X-ray absorption on the M4 and M5 edges of Pr to directly determine Pr3+ and Pr4+ in Lu2SiO5, Y2SiO5, and Lu3Al5O12. The spectra were measured at room temperature and compared to model samples of trivalent and tetravalent praseodymium, which provided clear signatures of the two charge states. The results show predominant Pr(III) in most samples.

Super-resolution upconversion microscopy of praseodymium-doped yttrium aluminum garnet nanoparticles

We demonstrate background-free subdiffraction optical microscopy with upconverting YAG nanoparticles doped with trivalent praseodymium ions ($Pr:\text{YAG}$). The presented microscopy with $Pr:\text{YAG}$ nanoparticles takes advantage of three facts. First, while excited with visible laser light, $Pr:\text{YAG}$ nanoparticles can emit upconverted ultraviolet (UV) radiation, thus allowing for background-free microscopy. Second, the technique based on exploiting donut-shaped laser beam was introduced to obtain subdiffraction-limited optical resolution. All optical resolution of 50 nm limited by the size of the particles was achieved. Third, $Pr:\text{YAG}$ nanoparticles are absolutely photostable. This technique resembles stimulated emission depletion microscopy (STED) though it is significantly different from STED since it involves stimulated absorption rather than stimulated emission.