Search results for "Yttrium"

2003

Hydrogenolysis of the dialkyl complexes [Y(η5-C5Me4SiMe2R)(CH2SiMe3)2(THF)] (1a, R = Me; 1b, R = Ph) results in the formation of the tetranuclear dihydrido complexes [{(η5-C5Me4SiMe2R)Y}4(μ-H)4(μ3-H)4(THF)2] (2a, R = Me; 2b, R = Ph), characterized by NMR spectroscopy. 2a was studied by single crystal X-ray diffraction. In the solid state, an unsymmetrical tetrahedral configuration of four [Y(η5-C5Me4SiMe3)] units is observed, two of which contain each one molecule of THF. Each yttrium atom is bonded to two μ2- as well as three μ3-bridging hydrido ligands. Synthese und Charakterisierung eines vierkernigen Hydrid-Clusters von Yttrium [{η5-(C5Me4SiMe3)Y}4(μ-H)4(μ3-H)4(THF)2] Die Hydrogenolyse …

Synthesis and Characterization of Yttrium Complexes Containing a Tridentate Linked Amido−Cyclopentadienyl Ligand

1998

The reaction of dilithium salts of the tridentate linked amido−cyclopentadienyl ligands Li2(C5Me4SiMe2NCH2CH2X) (X = OMe, NMe2, CH2OMe) with [Y(o-C6H4CH2NMe2)Cl2(LiCl)(THF)4] and Y(η5-C5H5)Cl2(THF)3 give chloro-bridged ate complexes of the type [Li(THF)][Y(η5:η1-C5Me4SiMe2NCH2CH2X)(R)Cl], where R = o-C6H4CH2NMe2, η5-C5H5.

Further synthetic investigation of the general lanthanoid(iii) [Ln(iii)]/copper(ii)/pyridine-2,6-dimethanol/carboxylate reaction system: {CuII5LnIII4…

2021

In addition to previously studied {CuII3Gd6}, {CuII8Gd4}, {CuII15Ln7} and {CuII4Ln8} coordination clusters (Ln = trivalent lanthanide) containing pdm2− or Hpdm− ligands (H2pdm = pyridine-2,6-dimethanol) and ancillary carboxylate groups (RCO2−), the present work reports the synthesis and study of three new members of a fifth family of such complexes. Compounds [Cu5Ln4O2(OMe)4(NO3)4(O2CCH2But)2(pdm)4(MeOH)2] (Ln = Dy, 1; Ln = Tb, 2; Ln = Ho, 3) were prepared from the reaction of Ln(NO3)3·xH2O (x = 5, 6), CuX2·yH2O (X = ClO4, Cl, NO3; y = 6, 2 and 3, respectively), H2pdm, ButCH2CO2H and Et3N (2 : 2.5 : 2 : 1 : 9) in MeCN/MeOH. Rather surprisingly, the copper(II)/yttrium(III) analogue has a sli…

Dimeric Hydrido Complexes of Rare-Earth Metals Containing a Linked Amido−Cyclopentadienyl Ligand:  Synthesis, Characterization, and Monomer−Dimer Equ…

2000

Dimeric hydrido complexes of lutetium, ytterbium, and yttrium containing a linked amido−cyclopentadienyl ligand, [Ln(η5:η1-C5Me4SiMe2NCMe2R)(L)(μ-H)]2 (Ln = Lu, Yb, Y; R = Me, Et; L = THF, PMe3), w...

Activation of C−H Bonds in Five-Membered Heterocycles by a Half-Sandwich Yttrium Alkyl Complex

2001

Yttrium Alkyl and Hydrido Complexes Containing a Tridentate-Linked Amido-Cyclopentadienyl Ligand

2003

A tridentate-linked amido-cyclopentadienyl ligand (C5Me4CH2SiMe2NCH2CH2NMe2)2- (L) was coordinated at yttrium to give the alkyl complex [Y(L)(CH2SiMe3)(THF)] (2), which reacts with H2 to give the T...

Dopant-Host oxide interactions and proton mobility in Gd:BaCeO3

2009

The local structure of Gd:BaCeO3 at different dopant concentrations (2-20%) was studied by X-ray absorption spectroscopy. The EXAFS analysis shows that the environment of the regular Ba2+ and Ce4+ cations is to a limited extent affected by doping. The local structure of gadolinium shows an expansion of the first coordination shell of oxygens, consistent with the ionic radius of Gd3+, but a contraction of the next neighboring shells of cations. In particular, the Ba2+ second neighbors get closer to the dopant, which can be originated by the effective negative charge sharply localized on the dopant. Comparison between EXAFS data of dry and hydrated compounds confirms this interpretation, show…

THE FATE OF ZR AND HF IN AQUATIC SYSTEMS UNDER THE EFFECTS OF SOLID-LIQUID INTERFACE PROCESSES, INTERPRETED IN THE LIGHT OF BEHAVIOUR OF RARE EARTHS …

2012

Yttrium and lanthanides in human lung fluids, probing the exposure to atmospheric fallout.

2011

International audience; Inhalation of airborne particles can produce crystallization of phosphatic microcrysts in intraaveolar areas of lungs, sometimes degenerating into pulmonary fibrosis. Results of this study indicate that these pathologies are induced by interactions between lung fluids and inhaled atmospheric dust in people exposed to volcanic dust ejected from Mount Etna in 2001. Here, the lung solid-liquid interaction is evaluated by the distribution of yttrium and lanthanides (YLn) in fluid bronchoalveolar lavages on selected individuals according the classical geochemical approaches. We found that shale-normalised patterns of yttrium and lanthanides have a 'V shaped' feature corre…

Geochemical behaviour of rare earths in Vitis vinifera grafted onto different rootstocks and growing on several soils.

2014

The geochemical behaviour of lanthanides and yttrium (Rare Earth Elements, REEs) has been investigated mainly in geological systems where these elements represent the best proxies of processes involving the occurrence of an interface between different media. This behaviour is assessed according to features recorded in sequences of REE concentrations along the REE series normalised with respect to a reference material. In this study, the geochemical behaviour of REE was investigated in different parts of Vitis vinifera specimens grown off-soil, on soils of different nature and grafted onto several rootstocks in order to evaluate effects induced by these changes. The results indicated that ro…