A Mass Spectrometric Study of the Sublimation of Lutetium Tribromide under Knudsen and Langmuir Conditions

The molecular and ionic sublimation of lutetium tribromide under thermodynamic equilibrium (Knudsen effusion) conditions and from the open surface of a LuBr₃ single crystal (Langmuir conditions) was studied by high-temperature mass spectrometry. Vapor contained the LuBr₃, Lu₂Br₆, Lu₃Br₉, and Lu₄Br₁₂ molecules and the Br^?, LuBr₄ ^?, Lu₂Br ₇ ^? , and Lu₃Br ₁₀ ^? negative ions. The partial pressures of the molecules in saturated vapor and the ratio between the sublimation coefficients of monomers and dimers under free vaporization conditions were determined. The degree of the electron impact-induced fragmentation of LuBr₃ molecules under Knudsen and Langmuir sublimation conditions was analyzed. The second and third laws of thermodynamics were used to calculate the enthalpies of sublimation in the form of monomers and oligomers (Knudsen vaporization) and the corresponding activation energies of sublimation (Langmuir vaporization). Ion—molecular equilibria with the participation of negative ions were studied. The enthalpies of formation of molecules and ions in the gas phase were obtained.     

Novel Lu3+ Carbon Paste Electrode Based on Functionalized Multiwalled Carbon Nanotubes

A novel carbon paste ion selective electrode for determination of trace amount of lutetium was prepared. Modified (functionalized) multiwalled carbon nanotubes (f‐MWCNTs) were used for improvement of a lutetium carbon paste sensor response. MWCNTs have a good conductivity which helps the transduction of the signal in carbon paste electrode. In this work it is shown that introducing certain functional groups on MWCNTs can improve the electrode signals. The electrode composition of 20 % paraffin oil, 56 % graphite powder, 18 % ionophore and 6 % f‐MWCNTs showed the stable potential response to Lu³⁺ ions with the Nernstian slope of 21.1 (±0.3) mV decade^?1 over a wide linear concentration range of 1.0×10^?6–1.0×10^?1 mol L^?1. The electrode has fast response time (<15 s) and long term stability (about one month).     

Securing a Supramolecular Architecture by Tying a Stopper Knot

We report on a rotaxane‐like architecture secured by the in situ tying of an overhand knot in the tris(2,6‐pyridyldicarboxamide) region of the axle through complexation with a lanthanide ion (Lu³⁺). The increase in steric bulk caused by the knotting locks a crown ether onto the thread. Removal of the lutetium ion unties the knot, and when the axle binding site for the ring is deactivated, the macrocycle spontaneously dethreads. When the binding interaction is switched on again, the crown ether rethreads over the 10 nm length of the untangled strand. The overhand knot can be retied, relocking the threaded structure, by once again adding lutetium ions.     

Synthesis and characterization of Eu<Superscript>3+</Superscript> doped Lu<Subscript>2</Subscript>O<Subscript>3</Subscript> nanophosphor using a solution-combustion method

Fine Eu³⁺-doped lutetium oxide (Lu₂O₃:Eu³⁺) nanophosphor were synthesized using a low-temperature solution-combustion method in a methyl-alcohol solution. The characteristics of the nanophosphors synthesized at various sintering temperatures with different Eu³⁺ concentrations were analyzed to determine the optimum synthesis conditions. Thermogravimetry/differential thermal analysis showed that Lu₂O₃:Eu³⁺ crystallizes completely when the dry powder is sintered at 500 °C. The Lu₂O₃:Eu³⁺ crystals had a cubic structure and monoclinic phase. The peak position of the luminescence spectrum did not differ with the concentration of Eu or the sintering temperature or atmosphere, whereas the luminescence intensity was strongly dependent on the concentration and sintering conditions.     

Photoluminescence and structural characteristics of Lu2O3:Eu nanocrystallites in silica matrix

Two silica ceramics were obtained by mixing nanocrystalline Lu₂O₃:Eu³⁺ with silica sol using the sol-gel technique. The synthesis procedure for both samples differed in the pH of the sol and time of the sol condensation before substrates were mixed together, which implied their different optical properties. The first one has the same spectroscopic properties as Lu₂O₃:Eu³⁺ nanocrystallites with an exception of small lowering of the charge transfer (CT) band intensity. This feature is preserved up to about 950 °C. Above this temperature, nanocrystallites of Lu₂O₃:Eu³⁺ react with the silica matrix synthesis pyrosilicate (Lu₂Si₂O₇). The Eu³⁺ ions occupy only one crystallographic site in the crystal lattice for low concentration of the activator (1%) and two sites for higher concentration (10%). The second sample exhibits different Eu³⁺ emission than Lu₂O₃:Eu³⁺ nanocrystallites and, additionally, a broad band of the matrix originating at the green region of the spectrum. Sintering the sample at higher temperatures leads to disappearance of this broad emission and continuous changes of the Eu³⁺ emission because of the progressive conversion of the Lu₂O₃:Eu³⁺ to pyrosilicate. At 1300 °C for both samples, the reaction of synthesis lutetium pyrosilicate is completed. Structural characteristic of the samples is presented and correlate with the decay profile of the Eu³⁺ emission.     

Effects of lutetium doping on the X-ray-excited luminescence properties of the tungstate Zn<Subscript>1−<Emphasis Type="Italic">x</Emphasis></Subscript>Lu<Subscript><Emphasis Type="Italic">x</Emphasis></Subscript>WO<Subscript>4</Subscript>

Polycrystalline samples in the lutetium-doped zinc tungstate system Zn_1?x Lu _x WO₄ with 0 ≤ x ≤ 0.08 were synthesized using the coprecipitation method followed by thermal treatment at 1000 °C during 4 h. The polycrystalline samples were characterized by X-ray diffraction analysis, scanning electron microscopy (SEM), infrared spectroscopy, and luminescence analysis under X-ray excitation. Rietveld analyses were performed. The variation of the wolframite structure cell parameters in the range 0 ≤ x ≤ 0.05 were congruent with substitution of Zn²⁺ by Lu³⁺. SEM micrographs of the obtained samples presented improved crystallization with morphology depending on the lutetium fraction. The luminescence spectra obtained under X-ray excitation (E < 40 keV) were in the blue–green region, and their intensity increased with x up to x = 0.05. The differences in the intensities of the X-ray luminescence spectra could be related to additional cation vacancies resulting from substitution of Zn²⁺ by Lu³⁺.     

Gas-phase synthesis of lanthanide(III) benzoates Ln(Bz)<Subscript>3</Subscript> (Ln = La,Tb, Lu)

A new method for the synthesis and film deposition of nonvolatile aromatic lanthanide(III) carboxylates by ligand exchange reaction between the starting volatile components in the gas phase was proposed. The complexes Ln(Bz)₃ (Ln = La³⁺, Tb³⁺, Lu³⁺, HBz = benzoic acid) were synthesized by gas-phase ligand exchange reaction between the volatile Ln(Thd)₃ and HBz (HThd = 2,2,6,6-tetramethylheptane-3,5-dione). The composition of the complexes was confirmed by elemental, thermal, IR-spectroscopic, and photoluminescence analyses and, in the case of lanthanum and lutetium complexes, by ¹H NMR.     

Oscillatory diffuse X-ray scattering from lead chalcogenides

New inorganic compounds having the general formula (Bi₂O₃)_1−x (Lu₂O₃) _x (x ranges from 0.1 to 0.5) displaying orange colours have been synthesized by traditional solid-state route, as viable alternatives to lead, cadmium and chromium based yellow toxic inorganic pigments. The host lattice of these pigments is Bi₂O₃ that is doped by Lu³⁺ ions. The goal was to develop conditions for the synthesis of these compounds and to determine the influence of calcination temperature and lutetium content on their colouring effects. The simultaneous TG-DTA measurements were used for determination of the temperature region of the pigment formation and thermal stability of pigments. The pigments were also evaluated from the standpoint of their structure and particle sizes.     

The First Example of μ-η 2:η 2-Peroxo-Bridged Macrocyclic Lanthanide Complex. The Crystal Structure of [Lu2{Me2pyo[16]trieneN5}2(μ-η 2:η 2-O2)Cl2](ClO4)2 Dioxane Solvate

The crystal structure of [Lu₂{Me₂pyo[16]trieneN₅}₂(μ-η ²:η ²-O₂)Cl₂](ClO₄)₂(1), where Me₂pyo[16]trieneN₅ is 2,14-dimethyl-3,6,10,13,19-pentaazabicyclo[13.3.1]nonadeca-1(19),2,13,15,17-pentaene reveals the biologically significant – unprecedented among the lanthanide macrocyclic complexes – planar side-on μ-η ²:η ² coordination mode of the peroxide as a result of [1 + 1] template Schiff base cyclocondensation of 2,6-diacetylpyridine with 3,7-diazanonane-1,9-diamine in the presence of mixed lutetium chloride and perchlorate salts followed by slow crystallization process.     

Synthesis and crystal structures of hydrogen and carbon stabilized lutetium monochloride,LuClHx and Lu2Cl2C

Single crystals of the, basically, four-layer slab structure …?ClLuLuCl…? of the apparently as such nonexisting lutetium monochloride, LuCl, stabilized by interstitial hydrogen or carbon have been obtained from reactions of LuCl₃ and cesium (LuClH_x, due to ubiquitous hydrogen) and C_sCl, lutetium and carbon (Lu₂Cl₂C), respectively, in sealed tantalum containers at elevated temperatures (above 700°C). Both exhibit so-called 3R structures (space group R3 m): LuClH_x (a = 363.83(3), c = 2710.2(3) pm, Z = 6) crystalizes with the ZrCl type structure with hydrogen in tetrahedral interstices and Lu₂Cl₂C (a = 360.17(3), c = 2716.0(3) pm, Z = 3) with the tetradymite type (Bi₂Te₂S) with carbon in octahedral interstices between the double metal layers. Power X-ray diffraction shows that for Lu₂Cl₂C a 1T structure is also adopted (a = 359.72(3), c = 909.25(9) pm, p3 m1, Z = 1).     

Structure of a new intermediate Lu2 + xS3 phase

A new intermediate phase in the Lu-S system, Lu_{2 + x}S₃, between the sulfur-rich end of the monosulfide homogeneity range and Lu₂S₃ was found to be isostructural with Sc₂S₃. The structure of Lu_{2 + x}S₃ is based upon the NaCl-type with a 12 times larger orthorhombic unit cell due to ordering on the vacant lutetium sites, and with ordered vacancies that differentiate it from Sc₂S₃.     

The electron affinity of tellurium

The electron affinity of tellurium has been determined to 1.970 876(7) eV. The threshold for photodetachment of Te^-(² P _3/2) forming neutral Te in the ground state was investigated by measuring the total photodetachment cross section using a collinear laser-ion beam geometry. The electron affinity was obtained from a fit to the Wigner law in the threshold region.     

Coordination Polymerization of Renewable 3‐Methylenecyclopentene with Rare‐Earth‐Metal Precursors

Coordination polymerization of renewable 3‐methylenecyclopentene has been investigated for the first time using rare‐earth metal‐based precursors bearing various bulky ligands. All the prepared complexes catalyze controllable polymerization of 3‐methylenecyclopentene into high molecular weight polymers, of which the NPN‐ and NSN‐tridentate non‐Cp ligated lutetium‐based catalytic systems exhibited extremely high activities up to 11 520 kg/(mol_Lu⋅h) in a dilute toluene solution (3.2 g/100 mL) at room temperature. The resultant polymers have pure 1,4‐regioregularity (>99 %) and tailorable number average molecular weights (1–20×10⁴) with narrow molecular weight distributions (polydispersity index (PDI)=1.45–1.79). DFT simulations were employed to study the polymerization mechanism and stereoregularity control.     

Rare-Earth Actived Sol-Gel Films for Scintillator Applications

Recently, there has been a growth of interest in new phosphors preparation for high resolution X-rays imaging systems. Sol-gel method has been used to synthesize europium doped gadolinium and lutetium oxide films. Structural and optical results are investigated and discussed on both Gd₂O₃:Eu³⁺ (5 mol%) and Lu₂O₃:Eu³⁺ (5 mol%). Those films are crystallized into cubic phase and present a density of 7.1 g/cm³ and 8.4 g/cm³ for Gd₂O₃:Eu³⁺ and Lu₂O₃:Eu³⁺ respectively. Room temperature emission spectra using an excitation of 468 nm was used to obtain the intense red emission ⁵D₀ ⁷F₂ (611 nm) of Eu³⁺. Scintillation properties at 611 nm are finally proved using X-rays excitation.     

Heterometallic Europium(III)–Lutetium(III) Terephthalates as Bright Luminescent Antenna MOFs

A new series of luminescent heterometallic europium(III)–lutetium(III) terephthalate metal–organic frameworks, namely (Eu_xLu_1−x)₂bdc₃·nH₂O, was synthesized using a direct reaction in a water solution. At the Eu³⁺ concentration of 1–40 at %, the MOFs were formed as a binary mixture of the (Eu_xLu_1−x)₂bdc₃ and (Eu_xLu_1−x)₂bdc₃·4H₂O crystalline phases, where the Ln₂bdc₃·4H₂O crystalline phase was enriched by europium(III) ions. At an Eu³⁺ concentration of more than 40 at %, only one crystalline phase was formed: (Eu_xLu_1−x)₂bdc₃·4H₂O. All MOFs containing Eu³⁺ exhibited sensitization of bright Eu³⁺-centered luminescence upon the 280 nm excitation into a ¹ππ* excited state of the terephthalate ion. The fine structure of the emission spectra of Eu^{3+ 5}D₀-⁷F_J (J = 0–4) significantly depended on the Eu³⁺ concentration. The luminescence quantum yield of Eu³⁺ was significantly larger for Eu-Lu terephthalates containing a low concentration of Eu³⁺ due to the absence of Eu-Eu energy migration and the presence of the Ln₂bdc₃ crystalline phase with a significantly smaller nonradiative decay rate compared to the Ln₂bdc₃·4H₂O.     

Electric transport in tungstates Ln<Subscript>2</Subscript>(WO4)<Subscript>3</Subscript> (La = Yb,Lu)

Electrical transport in orthorhombic ytterbium and lutetium tungstates with Sc₂(WO₄)₃ structural type was studied. It was proved by using two independent methods (EMF, dependence of conductivity on pressure of oxygen in the gas phase) that these phases are purely ionic conductors. It was found by Tubandt method for Lu₂(WO₄)₃ the negligible contribution of the [WO₄]^2– anion into transport, which, together with the results of the EMF technique, indicates a predominantly oxygen character of conductivity.     

Molecular structure of lutetium trichloride monomer and dimer

This paper reports on a simultaneous electron diffraction and mass spectrometric study of the saturated vapor of lutetium trichloride at T = 1070(10) K. It is found that the vapor consists of the monomer LuCl₃ [91.6(1.2) mol. %] and dimer Lu₂Cl₆. The following parameters were obtained for LuCl₃ (r_g configuration): r_g(Lu-Cl) = 2.403(5) Å, r_g(CL.Cl) = 4.119(18) Å,_g(Cl-Lu-Cl) = 117.9(1.3)?. Calculation of vibrational corrections for a transition from r_g to r_α geometry gave a planar equilibrium configuration for LuCl₃ with D_3h symmetry, whereas our previous electron diffraction study recommended a pyramidal configuration. Possible reasons for this controversy are discussed. The geometry of the Lu₂Cl₆ molecule of D_2h symmetry is described by the following parameters (ra configuration): r_α(Lu-Cl_t) = 2.366(5) Å, r_α(Lu-Clα) = 2.589(24) Å, ZCl_t-rLu-Cl_t = 119(7)?, ZCl_b-Lu-Cl_b = 84(2)?. The mean energies of the terminal [E(Lu-Cl_t) = 485 kJ/mole] and bridging [E(Lu-Cl_b) = 292 kJ/mole] bonds of Lu₂Cl₂₆ are estimated.     

The Synthesis of New Phthalocyanines Substituted with 12-Membered Diazadioxa Macrocycles

 A macrocyclic diazadioxa dibromo compound was synthesized by ring closure of 1,2-bis-(2-iodoethoxy)-4,5-dibromo-benzene and 1,4-bis-(p-tolylsulfonyl)-ethylenediamine. Its phthalonitrile derivative was obtained by cyano substitution. This diazadioxa macrocyclic dibromo derivative was directly converted into the copper(II) phthalocyanine by reaction with CuCN in tetramethyl urea. Conversion of this phthalonitrile derivative into the metal-free phthalocyanine was accomplished by refluxing with DBU. The zinc(II) phthalocyanine was prepared by reaction of the dinitrile derivative with Zn(OAc)₂ in quinoline. The lutetium bis-(phthalocyaninate) complex was obtained by treating the dinitrile derivative with anhydrous lutetium acetate and DBU in 1-hexanol. The new compounds were characterized by elemental analyses and IR, ¹H NMR, mass, UV/Vis, and ESR spectra.     

All‐Fullerene Electron Donor–Acceptor Conjugates

The synthesis and characterization of a covalent all‐fullerene C₆₀‐Lu₃N@I_h‐C₈₀ electron donor–acceptor conjugate has been realized by sequential 1,3‐dipolar cycloaddition reactions of azomethine ylides on Lu₃N@I_h‐C₈₀ and C₆₀. To the best of our knowledge, this is the first time that two fullerenes behaving as both electron donor (Lu₃N@I_h‐C₈₀) and acceptor (C₆₀) are forming an electroactive dumbbell. DFT calculations reveal up to 16 diastereomeric pairs, that is, 8 with syn and 8 with anti orientation, with the anti‐RSSS isomer being the most stable. Spectroelectrochemical absorption and femtosecond transient absorption experiments support the notion that a C₆₀^??‐Lu₃N@I_h‐C₈₀^?+ charge‐separated state is formed. Spin conversion from the charge‐separated singlet state C₆₀^??‐Lu₃N@I_h‐C₈₀^?+ into the corresponding triplet state is facilitated by the heavy‐atom effect stemming from the Lu₃N‐cluster, which, in turn, slows down the charge recombination by one order of magnitude.     

Ionic liquid-based hydrothermal synthesis of Lu2O3 and Lu2O3:Eu3+ microcrysals

Uniform and well-defined Lu₂O₃ and Lu₂O₃:Eu³⁺ microarchitectures have been successfully synthesized via a green and facile ionic liquid-based hydrothermal method followed by a subsequent calcination process. Novel 3D micro-rodbundles and 1D microrods of Lu₂O₃ and Lu₂O₃:Eu³⁺ were controllably obtained through this method. X-ray powder diffraction, scanning electron microscopy, transmission electron microscopy and photoluminescence spectra were used to characterize the micromaterials. The proposed formation mechanisms have been investigated on the basis of a series of SEM studies of the products obtained at different hydrothermal durations. The results indicated that hydrothermal temperature and the ionic liquid-tetrabutylammonium hydroxide were two key factors for the formation as well as the morphology control of the Lu₂O₃ and Lu₂O₃:Eu³⁺ microarchitectures.