Search results for "LANTHANIDE"
showing 10 items of 230 documents
Magnetic order in a CuII–DyIII oxamato-based two-dimensional coordination polymer
2019
Abstract We report the synthesis, crystal structure, and magnetic characterization of a novel two-dimensional copper(II)–dysprosium(III) coordination polymer of formula [LiI(OH2)4]2[DyIIICuII2(Me2pma)4Cl(H2O)] . 4H2O (1) [Me2pma = N-2,6-dimethylphenyloxamate]. Compound 1 was obtained using the mononuclear anionic complex [CuII(Me2pma)2]2–, as a bis(bidentate) metalloligand toward solvated dysprosium(III) cations, and it shows a square [DyIIICuII2] layered structure of (44.62) net topology. Interestingly, the combination of two factors, the well-known efficiency of oxamato ligands to transmit strong magnetic couplings between neighboring atoms and such structural topology, is responsible for…
Lanthanide complexation with CMPO and CMPO-calix[4]arenes in solution: spectrophotometric and electrospray mass spectrometric approaches.
2007
The binding of lanthanide(III) cations with organophosphorous ligands like CMPO and related calix[4]arene-based derivatives have been investigated using two experimental methods. The stability constants of the lanthanum, europium and ytterbium complexes were first determined in methanol by UV absorption spectrophotometry in the presence of nitrate or chloride anions. The results showed that the stoichiometry and the stability of the complexes formed depend on the position of the CMPO moieties either on the wide or the narrow rim of the calixarene scaffold, the nature of the medium, the conformational mobility of the ligands. Complexation of lanthanum was also followed by ESI-mass spectromet…
Slow relaxation in doped coordination polymers and dimers based on lanthanoids and anilato ligands
2019
Abstract In this work we report the synthesis, structure and magnetic properties of two lanthanoid based coordination polymers (CP) and two dimers prepared with two derivatives of the 2,5-dihydroxy-1,4-benzoquinone (C6O4X2)2− as ligands. Using the bromanilato ligand: (C6O4Br2)2− we have prepared the CP [Eu1.96Dy0.04(C6O4Br2)3(DMSO)6]·2DMSO (1) (DMSO = dimethylsulfoxide) and with the chlorocyananilato ligand: (C6O4(CN)Cl)2−) we have prepared one CP formulated as [Eu1.96Dy0.04(C6O4(CN)Cl)3(DMSO)6] (2) and two isostructural dimers: [Eu1.96Dy0.04(C6O4(CN)Cl)3(H2O)10]·6H2O (3) and [Eu2(C6O4(CN)Cl)3(H2O)10]·6H2O (4). Compounds 1, 2 and 3 are Eu(III) compounds doped with 2.0 % of Dy(III), whereas …
Hydrogen bond-mediated conjugates involving lanthanide diphthalocyanines and trifluoroacetic acid (Lnpc2@TFA): Structure, photoactivity, and stability
2020
The interaction between lanthanide diphthalocyanine complexes, LnPc2 (Ln = Nd, Sm, Eu, Gd, Yb, Lu
Full multiple scattering analysis of X-ray absorption near edge structure at the Eu L3-edge in EuO
2004
Abstract X-ray absorption near edge structure (XANES) at the Eu L 3 -edge in crystalline EuO is interpreted within full multiple scattering (FMS) formalism. Our theoretical results, based on the ab initio self-consistent (SC) potential calculations, are in good agreement with experimental data. The main features in the experimental signal are reproduced taking into account a cluster of about five coordination shells, centred at the europium atom and having EuO structure. An addition of more distant coordination shells makes features only better resolved. The relatively high intensity of the peak, located just above the Eu L 3 -edge, indicates that 5d states are well localised. Comparative a…
Radiochemical separation of no-carrier-added as produced via the process
2000
The 176Yb(n,gamma)177Yb-beta(-)-->177Lu process was investigated to provide no-carrier-added (nca) 177Lu. The radiochemical separation of the 177Lu from the macro-amounts of the ytterbium target based on the cementation process, i.e. the selective extraction of Yb by Na(Hg) amalgam from Cl-/CH3COO- electrolytes, followed by a final cation exchange purification. The cementation separation process provides a decontamination factor of Yb(III) of 10(4), the cation exchange purification adding a decontamination factor of > 10(2). The nca 177Lu is available in radiochemically pure form despite the chemical similarity of the lanthanides with 75 +/- 5% overall separation yield within 4-5 h. It can …
Tetra-CMPO-derivatives of calix[4]arenes fixed in the 1,3-alternate conformation
2010
Calix[4]arene derivatives fixed in the 1,3-alternate conformation and substituted at one side by four carbamoylmethylphosphine oxide (CMPO) residues were synthesised. Two CMPO groups are directly attached to the wide rim, while the second pair is bound to the narrow rim via a tri- or tetramethylene spacer. Similar compounds, in which two CMPO groups at the wide rim are combined with two picolinamide groups or two ionisable carboxylic groups at the narrow rim, were also prepared. Some of these calixarene derivatives were studied as extractants for lanthanides (La3+, Eu3+, Yb3+) and thorium (Th4+) from acidic solution into methylene chloride. For selected samples, stability constants in metha…
Preparation, characterization and photophysical properties of hybrid materials from rare earth complexes of phosphonato-substituted DOTAM derivatives
2011
Europium complexes [Eu.L]X33 (X = SO3CF3, NO3) of (diethoxyphosphorylnaphthyl)-substituted DOTAM were prepared and incorporated into titania and zirconia inorganic matrices. Zirconia revealed an appropriate matrix to achieve an efficient sensitization of emitting lanthanides.
Dimeric n-Alkyl Complexes of Rare-Earth Metals Supported by a Linked Amido−Cyclopentadienyl Ligand: Evidence for β-Agostic Bonding in Bridging n-Alk…
2002
The dimeric rare-earth hydrides [Ln(η^5:η^1-C_5Me_4SiMe_2NCMe_3)(THF)(μ-H)]_2 (Ln = Y, Yb) react with excess α-olefin H_2C ═ CHR (R = Et, ^nPr, ^nBu) in a 1,2-insertion to give the series of THF-free dimeric n-alkyl complexes [Ln(η^5:η^1-C_5Me_4SiMe_2NCMe_3)(μ-CH_2CH_2R)]_2 as isolable crystals. Single-crystal X-ray diffraction studies on the five derivatives [Y(η^5:η^1-C_5Me_4SiMe_2NCMe_2R‘)(μ-CH_2CH_2R)]_2 (R‘ = Me, R = Et, ^nBu; R‘ = Et, R = Et, ^nPr) and [Yb(η^5:η^1-C_5Me_4SiMe_2NCMe_3)(μ-CH_2CH_2^nBu)]_2 revealed that the centrosymmetric dimeric complexes consist of two trans-arranged [Ln(η^5:η^1-C_5Me_4SiMe_2NCMe_2R‘)] fragments connected by two μ-alkyl ligands. Most strikingly, there…
Selective Lanthanides Sequestration Based on a Self-Assembled Organosilica
2010
International audience; In this paper, we investigate the cation-exchange properties of a self-assembled hybrid material towards trivalent ions, lanthanides (La3+,Eu3+, Gd3+,Yb3+) and Fe3+. The bis-zwitter- ionic lamellar material was prepared by sol-gel process from only 3-amino- propyltriethoxysilane (APTES), succin- ic anhydride, and ethylenediamine. In ethanol heated under reflux, the ex- change ethylenediammonium versus Ln3+ proved to be complete by com- plexometry measurements and elemen- tal analyses, one Cl ion per one LnIII remaining as expected for charge bal- ance. In aqueous solution at 20 8C, the material was found to be selective to- wards lanthanide in spite of the similar- i…