10361-79-2Relevant articles and documents
Praseodymium hydroxide and oxide nanorods and Au/Pr6O 11 nanorod catalysts for CO oxidation
Huang,Wu,Zhu,Li,Wang,Gao,Zhu,Yan,Huang,Zhang,Song
, p. 1614 - 1620 (2006)
Praseodymium hydroxide nanorods were synthesized by a two-step approach: First, metallic praseodymium was used to form praseodymium chloride, which reacted subsequently with KOH solution to produce praseodymium hydroxide. In the second step the hydroxide was treated with a concentrated alkaline solution at 180°C for 45 h, yielding nanorods as shown by the scanning and transmission electron microscopy images. The results of X-ray diffraction and energy-dispersive X-ray spectroscopy experiments indicate that these nanorods are pure praseodymium hydroxide with a hexagonal structure, which can be converted into praseodymium oxide (Pr6O11) nanorods of a face-centered cubic structure after calcination at 600°C for 2 h in air. Gold was loaded on the praseodymium oxide nanorods using HAuCl4 as the gold source, and NaBH4 was used to reduce the gold species to metallic nanoparticles with sizes of 8-12 nm on the nanorod surface. These Au/Pr6O11 nanorods exhibit superior catalytic activity for CO oxidation.
Pr4N2S3 and Pr4N 2Se3: Two non-isostructural praseodymium(III) nitride chalcogenides
Lissner, Falk,Schleid, Thomas
, p. 427 - 432 (2005)
The non-isostructural nitride chalcogenides of praseodymium, Pr 4N2S3 and Pr4N2Se 3, are formed by the reaction of the praseodymium metal with sodium azide (NaN3), praseodymium trihalide (PrX3; X = Cl, Br, I) and the respective chalcogen (sulfur or selenium) at 900°C in evacuated silica ampoules after seven days. Both crystallize monoclinically in space group C2/c (Pr4N2S3: a = 1788.57(9), b = 986.04(5), c = 1266.49(6) pm, β = 134.546(7)°, Z = 8; Pr4N 2Se3: a = 1311.76(7), b = 1017.03(5), c = 650.42(3) pm, β = 90.114(6)°, Z = 4). The crystal structures of both compounds show a layered construction, dominated by N3--centred (Pr 3+)4 tetrahedra which share a common edge first. Continuing linkage of the so resulting bitetrahedral [N2Pr 6]12+ units via the non-connected vertices to layers according to ∞2{[N(Pr)2/2 e(Pr')2/2v]3+} forms different kinds of tetrahedral nets which can be described as layers consisting of four- and eight-rings for Pr4N2S3 and as layers of six-rings for Pr4N2Se3. Whereas the crystal structure of Pr4N2S3 exhibits four different Pr3+ cations with coordination numbers of six (2x) and seven (2x) against N3- and S2-, the number of cations in the nitride selenide (Pr4N2Se3) is reduced to half (Pr1 and Pr2) also having six- and sevenfold anionic coordination spheres. Further motifs for the connection of [NM4]9+ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare-earth elements with ratios of N:M = 1:2 are presented and discussed.
The dependence of persistent phosphorescence on annealing temperatures in CaTiO3:Pr3+ nanoparticles prepared by a coprecipitation technique
Zhang, Xianmin,Zhang, Jiahua,Ren, Xinguang,Wang, Xiao-Jun
, p. 393 - 398 (2008)
Red emitting phosphors of CaTiO3:Pr3+ nanoparticles with size ranging from 6 to 95 nm have been prepared by a coprecipitation technique and structurally characterized by X-ray diffraction, energy dispersive spectroscopy and scanning electron microscopy. The fluorescence and phosphorescence of CaTiO3:Pr3+ nanoparticles as a function of annealing temperature are investigated. It is found that fluorescence intensities monotonously increase with increasing temperature. However, a maximum in phosphorescence with the increase of annealing temperature occurs for the sample prepared at 700 °C. Based on the measurement of fluorescence emission, fluorescence excitation and reflectance spectra as well as time decay patterns of fluorescence and phosphorescence, it is demonstrated that the dependence of fluorescence and phosphorescence on annealing temperature originates from the decrease of surface defects with the increase of temperature.
Praseodymium β-diketonates and luminescence properties of their solutions
Meshkova,Kiriak,Topilova,Andrianov
, p. 556 - 561 (2007)
The luminescence intensity of Pr(III) in a series of complexes with alkyl and thienyl fluoroacetylacetone derivatives has been shown to increase not only with an increase in the length of the fluoroalkyl radical but also with the introduction of an oxygen heteroatom into this radical. The luminescence intensity of Pr(III) increases by about two orders of magnitude when a donor ligand (an organic solvent) is introduced into the complex. In some cases, the triplet level of β-diketone become higher due to interligand energy transfer and the Pr(III) luminescence occurs from two emitting levels 1 D 2 (the 1 D 2 → 3 H 4 transition, λlum = 605 nm) and 3 P 0 (the 3 P 0 → 3 H 6 transition, λ = 612 nm). Heteroleptic Pr(III) β-diketonates have short lifetimes (τ); for example, the lifetime of the Pr(III) complex with thenoyltrifluoroacetone and diantipyrylmethane is shorter than 1 μs. Nauka/Interperiodica 2007.
Pr6C2-bitetrahedra in Pr6C 2Cl10 and Pr6C2Cl5Br 5
Schaloske, Manuel C.,Mattausch, Hansjuergen,Kienle, Lorenz,Simon, Arndt
, p. 1493 - 1500 (2008)
The compounds Pr6C2Cl10 and Pr 6C2Cl5Br5 are prepared by heating stoichiometric mixtures of Pr, PrCl3, PrBr3 and C in sealed Ta capsules at 810-820°C. They form bulky transparent yellow to green and moisture sensitive crystals which have different structures: space groups C2/c, (a = 13.687(3) A, b = 8.638(2) A, c = 15.690(3) A, β = 97.67(3)° for Pr6C2Cl10 and a = 13.689(1) A, b = 10.383(1) A, c = 14.089(1) A, β = 106.49(1)° for Pr6C2Cl5Br5). Both crystal structures contain C-centered Pr6C2 bitetrahedra, linked via halogen atoms above edges and corners in different ways. The site selective occupation of the halogen positions in Pr 6C2Cl5Br5 is refined in a split model and analysed with the bond length-bond strength formalism. The compound is further characterized via TEM investigations and magnetic measurements (μeff = 3.66 μB).
The enthalpy of formation of the praseodymium ion (3+) in an infinitely dilute aqueous solution
Goryushkina,Monaenkova,Popova,Tiflova
, p. 697 - 701 (2006)
The enthalpy of reaction between praseodymium metal and 1.07 n HCl and the enthalpy of solution of praseodymium trichloride in 1.07 n HCl and water were measured in a swinging isoperibol calorimeter at 298.15 K. The results were used to calculate the enthalpy of formation of the praseodymium ion in the state of an infinitely dilute aqueous solution, Δf H° 298.15 Pr3+(sln, ∞H2O) = -687.8 ± 1.7 kJ/mol. Pleiades Publishing, Inc., 2006.
A novel 1D polyoxometallate-based coordination polymer [{Pr(DMSO) 6(H2O)}(PMo12O40)·CH 3CN]n: Properties, crystal structure and characterization
Niu, Jing-Yang,Wei, Mei-Lin,Wang, Jing-Ping
, p. 147 - 152 (2004)
A novel compound, [{Pr(DMSO)6(H2O)}(PMo 12O40)·CH3CN]n, has been synthesized and characterized by IR and single crystal X-ray structural analysis. It forms an one-dimensional zigzag chain built from alternating polyanions and cationic units through Mo-Ot-Pr-Ot-Mo links in the crystal. The results of the single crystal X-ray diffraction analyses and IR are agreement and both show the metal cation units are coordinately bonded to the Keggin cluster. The low temperature ESR spectrum indicates thermal electron delocalization occurs among the Mo atoms in the compound. The result of CV shows that the title compound undergoes five two-electron reversible reductions and that [PMo12O 40]3- anions are active centre for electrochemical redox in the solutions, while matched cations have small effect on electrochemical redox.
Thermal and spectroscopic studies on solid Ketoprofen of lighter trivalent lanthanides
Galico, D. A.,Holanda, B. B.,Perpetuo, G. L.,Schnitzler, E.,Treu-Filho, O.,Bannach, G.
, p. 371 - 380 (2012/04/23)
Solid-state Ln(L)3 compounds, where Ln stands for trivalent La, Ce, Pr, Nd, Sm, Eu, and L is ketoprofen have been synthesized. Thermogravimetry (TG), differential thermal analysis (DTA), differential scanning calorimetry (DSC) as well as X-ray diffraction powder (DRX) patterns, Fourier transformed infrared spectroscopy (FTIR), and other methods ofanalysis were used to study solid Ketoprofen of lighter trivalent lanth anides. The results provided information of the composition, dehydration, coordination mode, structure, thermal behavior, and thermal decomposition. The theoretical and experimental spectroscopic study suggests that the carboxylate group of ketoprofen is coordinate to metals as bidentatebond.
Synthesis, thermal properties and spectroscopic study of solid mandelate of light trivalent lanthanides
Gigante,Gomes,Lima,Caires,Treu-Filho,Ionashiro
, p. 6 - 14 (2012/05/31)
Characterization, thermal stability and thermal decomposition of light trivalent lanthanide mandelates Ln(C6H5CH(OH)CO 2)3·nH2O (Ln = La to Gd, except Pm) were investigated employing simultaneous thermogravimetry and differential thermal analysis (TG-DTA), differential scanning calorimetry (DSC), experimental and theoretical infrared spectroscopy, elemental analysis, X-ray diffractometry, complexometry and TG-DSC coupled to FTIR. The dehydration of the lanthanum, samarium, europium and gadolinium compounds occurs in a single step while for praseodymium and neodymium ones it occurs in two consecutive steps. The thermal decomposition of the anhydrous compounds occurs in three, four or five consecutive steps, with formation of the respective oxides CeO2, Pr6O11 and Ln2O3 (Ln = La, Nd to Gd) as final residues. The results also provide information concerning the composition, thermal behavior and gaseous products evolved during the thermal decomposition of these compounds. The theoretical and experimental spectroscopic data suggest the possible modes of coordination of the ligand with the lanthanum.
Comparison of covalency in the lanthanide chloride and nitrate complexes based on the adsorption data on zeolite y
G?adysz-P?aska, Agnieszka,Majdan, Marek,Ferenc, Wies?awa,Sarzyński, Jan
, p. 469 - 474 (2012/03/22)
The changes of the distribution constants Kd of lanthanide chlorides in the system: zeolite Y (solid phase)-sodium chloride (aqueous phase) were investigated. The evident tetrad effect in the change of log Kd values within the lantha
