Yb Metal Research Articles

Extraction of rare-earth, yttrium, and scandium perchlorates by podands bearing diphenylphosphorylacetamide terminal groups

Partition of trace amounts of metal (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Y, and Sc) perchlorates was studied between aqueous HClO4 solutions and dichloroethane solutions of phosphorus podands bearing two Ph2P(O)CH2C(O)NH-terminal groups linked via di-and triethylene glycol spacers. The stoichiometry of extracted complexes was determined. The efficiency of metal ion recovery to the organic phase was studied as a function of aqueous HClO4 concentration and nature of the organic solvent. The compounds synthesized have higher metal extraction capacities in HClO4 solutions than (dibutylcarbamoyl)diphenylphoshine oxide. The utility of macroporous polymer sorbents impregnated by these podands for extracting and concentrating rare earth(III) and scandium(III) ions from aqueous perchlorate solutions was demonstrated.

Crystallography and photoluminescence properties of β-diketonate monoporphyrinate ytterbium(III) complexes

The structures of two β-diketonate monoporphyrinate ytterbium(III) complexes were characterized by single-crystal X-ray diffraction analysis revealing, for the first time, seven-coordinate Yb(III) metal centers. The results reveal that there is only one solvent molecule (water or methanol) coordinating to ytterbium(III) in the complexes. Their photoluminescence of complexes in solution also shows that water and methanol that bind to ytterbium(III) ion quench the near-infrared emission of lanthanide, resulting a shorter lifetime (∼2.4 μs).

Abbau von Koordinationspolymeren bis zum Monomer und Konkurrenz von Polymerisation und Chemischer Schere an Carbazolaten von Yb und Eu mit N‐Phenylpiperazin

AbstractDegradation of Coordination Polymers to the Monomer and Competition of Polymerization and Chemical Scissors on Carbazolates of Yb and Eu with N‐PhenylpiperazineThe coordination polymers $^{1}_{\infty}\rm [Ln_{2}(Cbz)_{4}]$, Ln = Yb, Eu, Cbz− = carbazolate anion, C12H8N−, can be degraded by the use of strong N‐donor ligands like N‐phenylpiperazine (Phpip = (C6H5)C4H8NNH) as chemical scissors. The degradation process for the ytterbium containing polymer ends in the monomeric compound [Yb(Cbz)3(Phpip)2]·1/2Phpip and includes an oxidation step YbII → YbIII. Thus the circle of reactions of Yb metal with carbazole (CbzH) starting in liquid NH3 to the coordination polymer and ending with its degradation by the use of chemical scissors is resolved. Transformation on europium has been started on the base of both metals leading to coordination polymers of the same chemical formula. However already the prelude of reactions differs for Eu as the electride induced reaction of Eu metal with CbzH in liquid ammonia followed by Phpip treatment gives single crystalline [Eu2(Cbz)4(NH3)2(Phpip)4]·2Phpip. This dimeric molecule contains EuII and ligands of all reaction steps, NH3, Cbz−, Phpip, and is thereby an interesting starting point for the resolution of polymer formation and degradation as well as a competition of these counter reactions.

Investigation of an efficient YbF 3/Al cathode for tris-(8-hydroxyquinoline)aluminum-based small molecular organic light-emitting diodes

Efficient tris-(8-hydroxyquinoline)aluminum (Alq 3)-based organic light-emitting diodes (OLEDs) using YbF 3 as the electron injection layer have been investigated. With an YbF 3 (3.0 nm)/Al cathode, the device with Alq 3 as the emitting layer achieved a better performance than the control device with a LiF (0.5 nm)/Al cathode. The release of the low-work-function metal Yb is responsible for the performance enhancement. From the analysis by atomic force spectroscopy and X-ray photoemission spectroscopy, it is observed that the Alq 3-cathode interface could be well covered by YbF 3 at an optimum thickness of 3.0 nm, which helps to prevent the contact between Alq 3 and Al, and to reduce the destruction of Alq 3 by Al.

Fabrication of YbAl 3 film via annealing amorphous Yb–Al film deposited by RF magnetron sputtering

YbAl 3 single-phase bulk alloy was synthesized by melting at 1258 K using raw Yb and Al metals in the ratio of 1:2.2. A sputtering YbAl 3 target was prepared using the precursor YbAl 3 bulk alloy with the spark plasma sintering process. An amorphous Yb–Al film was fabricated by RF magnetron sputtering using the YbAl 3 target, and a single-phase crystalline YbAl 3 film was fabricated by annealing the amorphous Yb–Al film at temperatures higher than 923 K in Ar atmosphere.

A Coordinatively Linked Yb Metal–Organic Framework Demonstrates High Thermal Stability and Uncommon Gas‐Adsorption Selectivity

A Coordinatively Linked Yb Metal–Organic Framework Demonstrates High Thermal Stability and Uncommon Gas‐Adsorption Selectivity

A Coordinatively Linked Yb Metal–Organic Framework Demonstrates High Thermal Stability and Uncommon Gas‐Adsorption Selectivity

Narrow pores for high selectivity: The ytterbium metal–organic framework PCN-17, which contains coordinatively (through SO42− ions) linked, doubly interpenetrated (8,3)-nets (see picture), is stable up to 480 °C and exhibits selective adsorption of H2 and O2 over N2 and CO.

Small Steric Variations in Ligands with Large Synthetic and Structural Consequences

AbstractThe reaction of ytterbium metal with the aminopyridines2,6‐(diisopropylphenyl)‐[6‐(2,6‐dimethylphenyl)pyridin‐2‐yl]amine (1, Ap′H) and (2,4,6‐trimethylphenyl)‐[6‐(2,4,6‐trimethylphenyl)pyridin‐2‐yl]amine (2, ApMeH) at elevated temperature under vacuum in the presence of mercury gave rise to divalent [Yb(Ap′)2] (3) and trivalent [Yb(ApMe)3] (4), respectively. The single‐crystal X‐ray structure analysis of 3 revealed a four‐coordinate ytterbium atom with two chelating (N,N′) Ap′ ligands inclined to each other at an angle of 126.93(7)° (Cl–Yb–C26). Additionally the complex forms intermolecular CAryl–H agostic interactions [Yb1···C17 2.981(2) Å and Yb1···H17 2.56(3) Å] (all H atoms refined). Complex 4 contains a six‐coordinate ytterbium atom having three chelating (N,N′) ApMe ligands and has distorted octahedral stereochemistry. The reaction of the potassium salts of Ap′H (5) and ApMeH (6) with [YbI2 (thf)4] in thf gave rise to the divalent lanthanoid complexes [Yb(Ap′)2(thf)] (7), and [Yb(ApMe)2(thf)2] (8), respectively, and 7 was also obtained by redox transmetallation/ligand exchange from Yb metal, HgPh2 and Ap′H. X‐ray crystal structures show that 7 and 8 have five‐ and six‐coordinate ytterbium atoms and distorted trigonal‐bipyramidal and distorted octahedral stereochemistry, respectively, the difference in coordination number reflecting the difference in steric demand of the Ap′ and ApMe ligands.(© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2008)

Specific features of the formation of ytterbium films on the Si(111) surface at room temperature

The processes accompanying the formation of ytterbium films on the Si(111) surface at room temperature are investigated by the contact potential difference method, Auger electron spectroscopy, low-energy electron diffraction, and thermal desorption spectroscopy. It is shown that the grown metal films are uniform in thickness and that Si atoms virtually do not dissolve in the films. The atoms of the silicon substrate can diffuse in limited amounts into the Yb metal film only when the surface is bombarded by high-energy primary electron beams employed in Auger electron spectroscopy. The results obtained permit the conclusion that the previously observed oscillations of the work function in Yb-Si(111) thin-film structures cannot originate from dissolution of silicon atoms in the ytterbium film.

Spectral and nonlinear optical properties of metal complexes with 1,2-naphthalocyanine in silicate gel matrices

We have studied the influence of the method for embedding metal (Yb or Zn) complexes with 1,2-naphthalocyanine into nanoporous silicate xerogels (directly during sol-gel synthesis or by impregnation of the xerogel) and the nature of the Yb3+ exoligand (anionic Cl− or acetylacetone) on the spectral properties and structure of impurity molecular centers. It is shown that the degree of protonation and/or aggregation of the studied metal complexes is determined by the average surface concentration of HO-Si≡ silanol groups of the gel-matrix nanopores. It is established that the Yb complex with 1,2-naphthalocyanine and the anionic ligand Cl− penetrates to the greatest extent from solution into the inner cavities of the xerogel (degree of impregnation). This is due to quasichemical interaction of pigment molecules with the dehydroxylated nanopore surface containing ≡Si-O-Si≡ siloxane bridges. It is shown that the investigated metal complexes in both liquid solutions and solid-state silicate gel-matrices have a limiting effect on powerful optical radiation.

Ba, Si, U, Al, Sc, La, Th, C and 13C/ 12C in a sediment core in the western subarctic Pacific as proxies of past biological production

A sediment core covering the last 145 kyrs was collected in the western subarctic Pacific (WSAP), and analyzed for Ba, U, Al, Sc, La, Yb, Th, biogenic opal (Opal) and organic carbon (C org) as well as its isotopic ratio ( δ 13C). This study examined the change of past biological production in WSAP with multiple proxies, together with understanding the relation between Loess from the Asian continent and the biological production. The Loess content was estimated from the metal components, Al, Sc, La, Yb and Th. In this high latitude core (50°N), the Loess content was generally high during the glacial periods, but it was also high even in some interglacial periods. The excess amount of Ba relative to the detrital material composition, Ba ex, showed the best correlation with the Vostok δD ( r = 0.72, p < 0.001), indicating that the biological production was lower in the glacial periods than in the interglacials. This corroborates the pervasive correlation between Ba ex in the polar region, WSAP and the Antarctic Sea, and Antarctic temperature, combined with previous research. This correlation might be explained by the stratification caused by cooling. In addition, the time variations of Ba ex in WSAP were similar to those of Ba ex in the Okhotsk Sea and of other proxies (C org and Opal) in both the Okhotsk and the Bering Sea, indicating the spatial homogeneity of Ba ex in WSAP including proximal marginal seas. The Opal content was more weakly correlated with the Vostok δD ( r = 0.46, p < 0.001) than Ba ex, reflecting that Opal in WSAP including proximal marginal seas was spatially heterogeneous compared to Ba ex. While both the C org content and U ex, the excess amount of U relative to the detritus composition, were not positively correlated with the Vostok δD, they behaved similarly in the sediments. The positive correlation between δ 13C and the Vostok δD ( r = 0.42, p < 0.001), between δ 13C and Ba ex ( r = 0.60, p < 0.001) and between δ 13C and Opal ( r = 0.36, p < 0.01) indicates that δ 13C in WSAP may give some information on the phytoplankton growth rate. There was not a significant correlation between the spatially homogeneous Ba ex in WSAP and Loess ( r = − 0.16, p > 0.01), suggesting that the increase of biological production with the increase of Loess supply during the glacial periods did not occur.

Mesoporous titanium dioxide as a novel solid-phase extraction material for flow injection micro-column preconcentration on-line coupled with ICP-OES determination of trace metals in environmental samples

Mesoporous titanium dioxide as a novel solid-phase extraction material for flow injection micro-column preconcentration on-line coupled with ICP-OES determination of trace metals (Co, Cd, Cr, Cu, Mn, Ni, V, Ce, Dy, Eu, La and Yb) in environmental samples was described. Possessing a high adsorption capacity towards the metal ions, mesoporous titanium dioxide has found to be of great potential as an adsorbent for the preconcentration of trace metal ions in samples with complicated matrix. The experimental parameters including pH, sample flow rate, volume, elution and interfering ions on the recovery of the target analytes were investigated, and the optimal experimental conditions were established. Under the optimized operating conditions, a preconcentration time of 90 s and elution time of 18 s with enrichment factor of 10 and sampling frequency of 20 h −1 were obtained. The detection limits of this method for the target elements were between 0.03 and 0.36 μg L −1, and the relative standard deviations (R.S.D.s) were found to be less than 6.0% ( n =7, c =5 ng mL −1). The proposed method was validated using a certified reference material, and has been successfully applied for the determination of the afore mentioned trace metals in natural water samples and coal fly ash with satisfactory results.

Structural characteristics and the temperature derivative of the electrical resistivity of liquid lanthanides

The technique of an analysis is described and structural characteristics of liquid metals are calculated in terms of the model of hard spheres whose diameters asymptotically tend to zero with increasing temperature. The structure factor of a liquid refractory metal near the first maximum has been established to only weakly depend on temperature. A sufficient condition for the validity of the hard-sphere model has been formulated. On the example of many liquid lanthanides, it has been shown that the model satisfying this condition relatively well reproduces not only the structure factor of the melt but also its electrical resistivity in the vicinity of the melting point of the metal. With increasing temperature, the resistivity ρ of trivalent lanthanides increases monotonically, whereas in the case of divalent metals Eu and Yb smooth minima appear in the temperature dependences of ρ. An analysis of the results of calculations suggests that the hard-sphere model used in terms of the electron theory can relatively well describe properties of at least those liquid metals which crystallize into lattices with a packing fraction η ≥ π √3 /8.

Lanthanide−Transition Metal Carbonyl Complexes: Condensation of Solvent-Separated Ion-Pair Compounds into Extended Structures

New solvent-separated ion-pair compounds and extended structures containing ytterbium(II)-transition metal isocarbonyl linkages were synthesized. [Yb(THF)6][M(CO)5]2 (1, M = Mn; 2, M = Re) were prepared via transmetalation reactions between Yb metal and Hg[M(CO)5]2 in THF. Reflux of 1 in Et2O afforded {Yb(THF)2(Et2O)2[(mu-CO)2Mn(CO)3]2}infinity (3) which is a sheet-layer structure. In ether solution, 3 is converted to {Yb(THF)4[(mu-CO)2Mn(CO)3]2}infinity (4) which has a linear structure. In both 3 and 4, ytterbium is 8-coordinated (distorted square antiprism geometry), four coordination sites occupied by molecules of solvent and four more by oxygen atoms of isocarbonyl linkages. The [Mn(CO)5]- anion has trigonal bipyramidal geometry and is linked to ytterbium through two equatorial carbonyls. The formation of two minor products, (THF)2Mn3(CO)10 (5) and [(THF)5Yb(mu-CO)Mn3(CO)13][Mn3(CO)14] (6), was observed during condensation of 1 into 3 and 4.

Application of metal-doped organic layer both as exciton blocker and optical spacer for organic photovoltaic devices

An effective optical spacer based on doping of ytterbium (Yb) metal into bathophenanthroline (BPhen) has been developed for applications in organic photovoltaic (OPV) devices. Utilizing Yb:BPhen as an optical spacer in standard copper phthalocyanine/C60 photovoltaic devices, power efficiency can be increased by four times to 3.42%. Ultraviolet photoemission spectroscopy measurements reveal that the good electron transport between C60 and Yb:BPhen is mainly related to the suitable energy level alignment at the interface. Combining with its high optical transparency and electrical conductivity, the Yb:BPhen film provides a useful means for maximizing the power conversion efficiency of OPV devices.

Pressure-Tuning of thec–fHybridization in Yb Metal Detected by Infrared Spectroscopy up to 18 GPa

It has been known that the elemental Yb, a divalent metal at mbient pressure, becomes a mixed-valent metal under external pressure, with its valence reaching ~2.6 at 30 GPa. In this work, infrared spectroscopy has been used to probe the evolution of microscopic electronic states associated with the valence crossover in Yb at external pressures up to 18 GPa. The measured infrared reflectivity spectrum R(w) of Yb has shown large variations with pressure. In particular, R(w) develops a deep minimum in the mid-infrared, which shifts to lower energy with increasing pressure. The dip is attributed to optical absorption due to a conduction c-f electron hybridization state, similarly to those previously observed for heavy fermion compounds. The red shift of the dip indicates that the $c$-$f$ hybridization decreases with pressure, which is consistent with the increase of valence.

Understanding mixed valent materials: Effects of dynamical core-hole screening in high-pressure x-ray spectroscopy

Changes in the electronic structure of Yb, a material whose valence is modified under pressure, are observed with remarkable detail in x-ray absorption and emission data measured between ambient conditions and $20\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$. These changes are reproduced by a theory that essentially does not rely on experimental parameters, and includes dynamical core-hole screening. From the combined experimental and theoretical data we can firmly establish on a quantitative level how the valency of an intermediate valence material is modified by pressure. In metallic Yb it increases from 2 to $2.55\ifmmode\pm\else\textpm\fi{}0.05$ between 0 and $20\phantom{\rule{0.3em}{0ex}}\mathrm{GPa}$.

Structure of Some 4f Rare Earth Liquid Metals —A Charged Hard Sphere Approach

A well-established pseodopotential is used to study the structureof some 4f rare earth liquid metals (Ce, Pr, Eu, Gd, Tb, and Yb).The structure factor S(q), pair distribution function g(r),interatomic distance r1, and coordination number n1 are calculatedusing Charged Hard Sphere (CHS) reference system. To introducethe exchange and correlation effects, the local field correctiondue to Sarkar et al. (S) is applied. The present investigationis successful in generating the structural information of Ce,Pr, Eu, Gd, Tb, and Yb 4f rare earth liquid metals.

Syntheses, structures, and vibrational spectroscopy of the two-dimensional iodates Ln(IO 3) 3 and Ln(IO 3) 3(H 2O) ( Ln[dbnd]Yb, Lu)

The reaction of Lu 3+ or Yb 3+ and H 5IO 6 in aqueous media at 180 °C leads to the formation of Yb(IO 3) 3(H 2O) or Lu(IO 3) 3(H 2O), respectively, while the reaction of Yb metal with H 5IO 6 under similar reaction conditions gives rise to the anhydrous iodate, Yb(IO 3) 3. Under supercritical conditions Lu 3+ reacts with HIO 3 and KIO 4 to yield the isostructural Lu(IO 3) 3. The structures have been determined by single-crystal X-ray diffraction. Crystallographic data are (Mo Kα, λ=0.71073 Å): Yb(IO 3) 3, monoclinic, space group P2 1/ n, a=8.6664(9) Å, b=5.9904(6) Å, c=14.8826(15) Å, β=96.931(2)°, V=766.99(13), Z=4, R( F)=4.23% for 114 parameters with 1880 reflections with I>2 σ( I); Lu(IO 3) 3, monoclinic, space group P2 1/ n, a=8.6410(9), b=5.9961(6), c=14.8782(16) Å, β=97.028(2)°, V=765.08(14), Z=4, R( F)=2.65% for 119 parameters with 1756 reflections with I>2 σ( I); Yb(IO 3) 3(H 2O), monoclinic, space group C2/ c, a=27.2476(15), b=5.6296(3), c=12.0157(7) Å, β=98.636(1)°, V=1822.2(2), Z=8, R( F)=1.51% for 128 parameters with 2250 reflections with I>2 σ( I); Lu(IO 3) 3(H 2O), monoclinic, space group C2/ c, a=27.258(4), b=5.6251(7), c=12.0006(16) Å, β=98.704(2)°, V=1818.8(4), Z=8, R( F)=1.98% for 128 parameters with 2242 reflections with I>2 σ( I). The f elements in all of the compounds are found in seven-coordinate environments and bridged with monodentate, bidentate, or tridentate iodate anions. Both Lu(IO 3) 3(H 2O) and Yb(IO 3) 3(H 2O) display distinctively different vibrational profiles from their respective anhydrous analogs. Hence, the Raman profile can be used as a complementary diagnostic tool to discern the different structural motifs of the compounds.

Optical properties of Er and Er+Yb doped hydrogenated amorphous silicon films

Hydrogenated amorphous silicon (a-Si:H) films were prepared by sputtering a Si target in an atmosphereof Ar+H2. TheEr (and Er+Yb) doping of the films was achieved by partially covering the Si target with small pieces of Er(Er+Yb) metal. After deposition the films were annealed up to700 °C in an inert atmosphere. Ion beam analyses, Raman spectroscopy, optical transmissionand photoluminescence measurements were employed for characterizationpurposes. According to the experimental results, thermal treatments up to∼300 °C do not significantly alter the composition, atomic structure or opticalbandgap of the present a-Si:H films. On the contrary, the Er-relatedphotoluminescence intensity at 1540 nm increases and reaches its maximum at about400 °C. Treatments attemperatures higher than ∼400 °C reduce both the Er-related light emission and the optical bandgap of the filmsdue to the out-diffusion of hydrogen atoms. Furthermore, the relatively smalloptical bandgap and the presence of tail states prevent any optical activity ofYb3+ ions in the measured a-Si:H films. At the present doping levels and sample characteristics,ytterbium only increases the incidence of non-radiative processes.