Crystal structure and luminescent properties of the complex [Eu(III)(TFPB)(3)bpy]

The crystal structure of Eu(TFPB)(3)bpy [TFPB: 4,4,4-trifluoro-1-phenyl-1,3-butanedione, bpy: 2,2'-bipyridyl] has been determined by single crystal X-ray diffraction and the coordination geometry of Eu atom is a square antiprism. The complex can give the characteristic luminescence of Eu3+ upon UV excitation.

Triboluminescence of a new europate complex

A new europium (III) complex Eu(HFNH)(3)Phen (HFNH: 4, 4, 5, 5, 6, 6, 6-heptafluoro-1-(2-naphthyl) hexane-1,3-dione; phen: 1, 10-phenanthroline) was synthesized and its triboltuninescent phenomenon was observed. Photoluminescence and triboluminescence spectra were successfully determined. The most intense triboluminescent emission originates front the transition of the, central Eu3+ ion from D-5(0) level to F-7(2) level. The triboluminescent spectrum is basically similar to that of photoluminescence, which correlates with the disorders of F atoms.

Extraction and separation of cadmium(II), iron(III), zinc(II), and europium(III) by Cyanex302 solutions using hollow fiber membrane modules

The mass transfer behaviors of Cd(II), Fe(III), Zn(II), and Eu(III) in sulfuric acid solution using microporous hollow fiber membrane (HFM) containing bis(2,4,4-trimethylpentyl)monothiophosphinic acid (commercial name Cyanex302) were investigated in this paper. The experimental results showed that the values of the mass transfer coefficients (K-w) decreased with an increase of H+ concentration and increased with an increase of extractant Cyanex302 concentration. The mass transfer resistance of Eu3+ was the largest because K-w value of Eu3+ was the smallest. The order of mass transfer rate of metal ions at low pH was Cd > Zn > Fe > Eu. Mixtures of Zn2+ and Eu3+ or of Zn2+ and Cd2+ were well separated in a counter-current circulation experiment using two modules connected in series at different initial acidity and concentration ratio. These results indicate that a hollow fiber membrane extractor is capable of separating the mixture compounds by controlling the acidity of the aqueous solution and by exploiting different mass transfer kinetics. The interfacial activity of Cyanex302 in sulfuric acid solution was measured and interfacial parameters were obtained according to Gibbs adsorption equation.

Kinetics of extraction and stripping of y(III) by Cyanex 272 as an acidic extractant using a constant interfacial cell with laminar flow

The extraction and stripping kinetics of yttrium(III) with bis(2,4,4-trimethylpentyl) phosphinic acid (Cyanex 272, HA) dissolved in heptane as an acid extractant have been investigated by constant interfacial cell with laminar flow. The experimental hydrodynamic conditions have been chosen so that the contribution of diffusion to the measured rate of reaction is minimized. The plot of interfacial area on the rate has shown a linear relationship, which makes the interface the most probable local for the chemical reactions. At the same time, the extraction thermodynamic and kinetic methods are compared to determine the equilibrium extraction constant. A rate equation and the rate-determining step of the extraction and stripping of yttrium(III) have also been obtained, respectively.

Solvent extraction of scandium(III), yttrium(III), lanthanum(III) and gadolinium(III) using Cyanex 302 in heptane from hydrochloric acid solutions

The extractions of the selected rare earths (Sc, Y, La and Gd) from hydrochloric acid solutions have been investigated using bis(2,4,4-trimethylpentyl)-mono thiophosphinic acid (Cyanex 302, HL) in heptane as an extractant. The results demonstrate that the extractions of rare earths occur via the following reaction: Sc(OH)(2+) + 2[(HL)(2)]((O)) double left right arrow [Sc(OH)L-2 (.) 2(HL)]((O)) + 2H(+) Y3+ + 3[(HL)(2)]((O)) double left right arrow [Y(HL2)(3)]((O)) + 3H(+) La(OH)(2)(+) + 3[(HL)(2)](O) double left right arrow [La(OH)(2)L (.) 5(HL)]((O)) + H+ Gd(OH)(2+) + 3[(HL)(2)]((O)) double left right arrow [Gd(OH)L-2 (.) 4(HL)]((O)) + 2H(+) The pH(1/2) values and equilibrium constants of the extracted complexes have been deduced by taking into account the aqueous phase complexation of the metal ion with hydroxyl ligands and plausible complexes extracted into the organic phase. According to the pH(1/2) values, it is possible to realize mutual separation among Sc(III), Y(III), La(III) and Gd(III) with Cyanex 302 by controlling aqueous acidity.

Adsorption of heavy rare earth(III) with extraction resin containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid

In the present paper, the adsorption of thulium(Ill) from chloride medium on an extraction resin containing bis(2,4,4-trimethylpentyl) monothiophosphinic acid (CL302, HL) has been studied. The results show that 1.5 h is enough for the adsorption equilibrium. The distribution coefficients are determined as a function of the acidity of the aqueous phase and the data are analyzed both graphically and numerically. The plots of log D versus pH give a straight line with a slope of about 3, indicating that 3 protons are released in the adsorption reaction of thulium(III). The content of Cyanex302 in the resin is determined to be 48.21%. The total amount of Tm3+ adsorbed up to resin saturation is determined to be 82.46 mg Tm3+/g resin. Therefore, the sorption reactions of Tm3+ from chloride medium with CL302 can be described as: Tm3+ + 3HL((r)) <----> TmL3(r) + 3H(+) The Freundlich's isothermal adsorption equation is also determined as: log Q = 0.73 log C + 3.05 The amounts (Q) of Tm3+ adsorbed with the resin have been studied at different temperatures (15-40degreesC) at fixed concentrations of Tm3+, amounts of extraction resin, ion strength and acidities in the aqueous phase.

Extraction and separation of cerium(IV) from nitric acid solutions containing thorium(IV) and rare earths(III) by DEHEHP

The extraction behaviour of Ce(IV), Th(IV) and part of RE(III), viz., La, Ce, Nd and Yb, has been investigated using di(2-ethylhexyl) 2-ethylhexyl phosphonate (DEHEHP,B) in heptane as an extractant. Results show that extractability varies in the order: Ce(IV) > Th(IV) much greater than RE(III). Therefore, it is possible to find the appropriate conditions under which Ce(IV) can be effectively separated from Th(IV) and RE(III). Furthermore, stripping Ce(IV) from the loaded organic phase can be carried out by dilute H2SO4 with an aliquot of H2O2.Roasted bastnasite made in Baotou (China) by Na2CO3 and leached by HNO3, there is about 50% Ce mainly as tetravalent nitrate along with other RE(III) and Th(IV) in the leachings. Through fractional extraction, taking nitric acid leachings of roasted Bastnasite as feed and DEHEHP as an extractant, we can obtain the CeO2 products with high purity of 99.9-99.99%, with a yield of >85%, in which ThO2/CeO2 < 10(-4).

Barycenter of energy of lanthanide 4f(N)-(1)5d configuration in inorganic crystals

A semiempirical method for the evaluation of the barycenter of energy of 4f(N-1)5d configurations is presented. The environmental factors affecting the barycenter are given to be the bond volume polarization, fractional covalence of the chemical bond between the central ion and the nearest anion, and presented charge of the nearest anion in the chemical bonds. The barycenter energies of 4f(N-1)5d configurations of Eu2+ and Ce3+ are calculated in various crystals, and the results are in good agreement with the experimental values. A relationship is found between the barycenter of energy of the 4f(N-1)5d configuration on Eu2+ method offers the advantage of applicability to a broad class of luminescence materials and initiates a link between macroscopic properties and microscopic structure.

Heptaaquatetra-mu(3)-hydroxy-hexa-mu(2)-L-leucine-(L-leucine)tetraytterbium(III) tetrachlorozinc(II) trichlorohydroxyzinc(II) tetrachloride octahydrate

The title bimetallic compound, [Yb-4(mu(3)-OH)(4)(C6H13NO2)(7)-(H2O)(7)][ZnCl4][ZnCl3(OH)]Cl-4.8H(2)O, was synthesized at near physiological pH (6.0). The compound exhibits some novel structural features, including an asymmetric [Yb-4(mu(3)-OH)(4)(L-leucine)(7)(H2O)(7)](8+) complex cation in which four OH groups act as bridging ligands, linking four Yb3+ cations into a Yb4O4 structural unit. Each pair of adjacent Yb3+ ions is further bridged by one carboxy group from a leucine ligand. Water molecules and a monodentate leucine ligand also coordinate to Yb3+ ions, completing their eight-coordinate square-antiprismatic coordination. The Yb-4(mu(3)-OH)(4)(L-leucine)(7)(H2O)(7)](8+) cation, the [ZnCl4](2-), [ZnCl3OH](2-) and Cl- anions, and the lattice water molecules are linked via hydrogen bonds.

Computer simulation of Gd(III) speciation in human interstitial fluid

The speciation and distribution of Gd(III) in human interstitial fluid was studied by computer simulation. The results show that at the background concentration, all the Gd(III) species are soluble and no precipitates appear. However as the total concentration of Gd(III) rises above 2.610 x 10(-9) mol/l the insoluble species become predominant. GdPO4 is formed first as a precipitate and then Gd-2(CO3)(3). Among soluble species, free Gd(III), [Gd(HSA)], [Gd(Ox)] and the ternary complexes of Gd(III) with citrate as the primary ligand are main species when the total concentration of Gd(III) is below 2.074 x 10(-2) mol/l. With the total concentration of Gd(III) further rising, [Gd-3(OH)(4)] begins to appear and gradually becomes a predominant species.

Investigation of sandwiched gadolinium(III) complexes with tungstosilicates as potential MRI contrast agents

Two gadolinium-sandwiched complexes with tungstosilicates, K-13[Gd(SiW11O39)(2)] (Gd(SiW11)(2)) and K11H6[Gd2O3(SiW9O34)(2)] (Gd-3(SiW9)(2)), have been investigated by in vitro and in vivo experiments as potential contrast agents for magnetic resonance imaging (MRI). T-1-relaxivity of Gd(SiW11)(2)was 6.59 mM(-1) . s(-1) in aqueous solution and 6.85 mM(-1) . s(-1) in 0.725 mmol . L-1 bovine serum albumin solution at 25degreesC and 9.39 T, respectively. The corresponding T-1-relaxivity of Gd-3(SiW9)(2) was 12.6 and 19.3 mM(-1) . s(-1) per Gd, respectively. MRI for Sprague-Dawley rats showed longer and more remarkable enhancement in rat liver after i.v. injection of these two complexes: 39.4 +/- 3.9% and 57.4 +/- 11.6% within the first 30 min after injection, 31.2 +/- 2.6% and 39.9 +/- 7.6% in the next 60 min for Gd(SiW11)(2) and Gd-3(SiW9)(2) at doses of 0.081 and 0.084 mmol Gd/kg, respectively. Our preliminary in vitro and in vivo study indicates that Gd(SiW11)(2) and Gd-3(SiW9)(2) are favorable candidates for hepatic contrast agents for MRI. However, the two complexes exhibit higher acute toxicity and need to be modified and studied further before clinical use.

Separation of yttrium from heavy lanthanide by CA-100 using the complexing agent

The selective extraction of yttrium front heavy lanthanide by liquid-liquid extraction using CA-100 in the presence of the complexing agent, such as EDTA, DTPA, and HEDTA was investigated. The extraction of heavy lanthanide in the present of the complexing agent was Suppressed when compared to that of Y because of the masking effect, but the selective extraction of Y was enhanced. All complexing agents formed 1: 1 complex with rare earth elements (RE), and only free rare earth ions could take part in the extraction. The condition for separation was obtained by exploring the effects of the complexing agent concentration, the extractant concentration, pH and the equilibration time on the extraction of the heavy rare earth elements.

Synthesis and structural characterization of beta-diketiminate-lanthanide Amides and their catalytic activity for the polymerization of methyl methacrylate and epsilon-caprolactone

The synthesis and catalytic activity of lanthanide monoamido complexes supported by a beta-diketiminate ligand are described. Donor solvents, such as DME, can cleave the chloro bridges of the dinuclear beta-diketiminate ytterbium dichloride {[(DIPPh)(2)nacnac]YbCl(mu-Cl)(3)Yb[(DIPPh)(2)nacnac](THF)} (1) [(DIPPh)(2)nacnac = N,N-diisopropylphenyl-2,4-pentanediimine anion] to produce the monomeric complex [(DIPPh)(2)nacnac]YbCl2(DME) (2) in high isolated yield. Complex 2 is a useful precursor for the synthesis of beta-diketiminate-ytterbium monoamido derivatives. Reaction of complex 2 with 1 equiv of LiNPr2i in THF at room temperature, after crystallization in THF/toluene mixed solvent, gave the anionic beta-diketiminate-ytterbium amido complex [(DIPPh)(2)nacnac]Yb(NPr2i)(mu-Cl)(2)Li(THF)(2) (3), while similar reaction of complex 2 with LiNPh2 produced the neutral complex [(DIPPh)(2)nacnac]Yb(NPh2)Cl(THF) (4). Recrystallization of complex 3 from toluene solution at elevated temperature led to the neutral beta-diketiminate-lanthanide amido complex [{(DIPPh)(2)nacnac}Yb(NPr2i)(mu-Cl)](2) (5). The reaction medium has a significant effect on the outcome of the reaction.

Systematic synthesis and characterization of single-crystal lanthanide phenylphosphonate nanorods

Using low-temperature hydrothermal methods, nanoscale lanthanide phenylphosphonates species with different morphologies, namely, nanoparticles and nanorods, have been systematically synthesized. The possible growth mechanism of these nanorods was discussed. X-ray diffraction, transmission electron microscopy, electron diffraction, and photoluminescence spectra were used to characterize these materials. The photoluminescent properties of EU(O3PC6H5)(HO3PC6H5) and La0.91EU0.09(O3PC6H5)(HO3PC6H5) nanorods were discussed.

Memory devices based on lanthanide (SM3+, EU3+, Gd3+) complexes

Memory effects in single-layer organic light-emitting devices based on Sm3+, Gd3+, and Eu3+ rare earth complexes were realized. The device structure was indium-tin-oxide (ITO)/3,4-poly(ethylenedioxythiophene)-poly(styrenesulfonate) (PEDOT)/Poly(N-vinyl carbazole) (PVK): rare earth complex/LiF/Ca/Ag. It was found experimentally that all the devices exhibited two distinctive bistable conductivity states in current-voltage characteristics by applying negative starting voltage, and more than 10(6) write-read-erase-reread cycles were achieved without degradation. Our results indicate that the rare earth organic complexes are promising materials for high-density, low-cost memory application besides the potential application as organic light-emitting materials in display devices.