Search results for "Vanadium"

The stoichiometry of blue vanadium doped zircon obtained by sol-gel methods

1992

Abstract In this study, Sol-Gel processes in aqueous solution were used to investigate the stoichiometry of the V/1bZrSiO 4 solid solutions achieved by this method. Compositions with a formal stoichiometric defect in: (a) ZrO 2 ([ZrO 2 ] 1−2x [SiO 2 ] [V 2 O 5 ] x ), and (b) in SiO 2 ([ZrO 2 ] [SiO 2 ] 1−2x [V 2 O 5 ] x ), x=0.02, 0.04, 0.05 and 0.10 have been prepared. X Ray Diffraction analyses in fired samples (1200°/3 days) showed that cristobalite and monoclinic zirconia appear as residual crystalline phase in (a) and (b) compositions respectively, except in sample (a) with x=0.02 in which no residual phase was detected and therefore is considered stoichiometric. This sample and sample…

Oxidovanadium(v) complexes with l-proline-based amino acid phenolates

2019

L-proline was used to prepare chiral, tridentate amino acid phenol proligands H2L1—4. These proligands react with vanadium precursors VO(acac)2, VOSO4 ∙ 5 H2O and VO(OPr)3 in methanol to form the corresponding oxidoalkoxidovanadium(V) complexes 1—4. The complexes crystallize from methanol, and are octahedrally coordinated with a general formula [VO(L1—4)(OMe)(MeOH)]. In solution, however, they adopt several different conformations or isomeric structures depending on the solvent. peerReviewed

CCDC 270841: Experimental Crystal Structure Determination

2005

Related Article: J.-P.Costes, S.Shova, J.M.C.Juan, N.Suet|2005|Dalton Trans.||2830|doi:10.1039/b506102d

CCDC 825040: Experimental Crystal Structure Determination

2013

Related Article: N.Marino, F.Lloret, M.Julve, R.P.Doyle|2011|Dalton Trans.|40|12248|doi:10.1039/c1dt11004g

Vanadium induces calcium depletion and cell selective apoptosis during development of sea urchin embryos

2021

Vanadium (V) is a metal widely distributed in soil, water and air. It has recently received growing interest because its compounds are often used in different applications, from industry to medicine.1 Here, using atomic absorption spectrometry, we demonstrate the predisposition of V to accumulate directly into embryonic cells, interfering with Ca uptake. At the morphological level, we observed dose- and time-dependent effects on phenotypes and on skeletal malformations. At the molecular level, V-exposed embryos showed the activation of the cellular stress response, inducing Hsp 60 and Hsp 70 synthesis and the activation of autophagy and apoptosis. The Hsps-mediated stress response to V appe…

CCDC 1848817: Experimental Crystal Structure Determination

2018

Related Article: Yan Hou|2018|CSD Communication|||

CCDC 2122007: Experimental Crystal Structure Determination

2022

Related Article: Cristina Negro, Cristina Bilanin, Xiaoni Qu, Judit Oliver-Meseguer, Jesús Ferrando-Soria, Antonio Leyva-Pérez, Donatella Armentano, Emilio Pardo|2022|Chem.Commun.|58|5578|doi:10.1039/D2CC01137A

Effect of hydrogen on the ethylene polymerization process over Ziegler–Natta catalysts supported on MgCl2(THF)2. I. Studies of the chain‐transfer rea…

2001

The effect of hydrogen on the molecular weight of polyethylene obtained over vanadium catalysts (based on VCl4 and VOCl3) supported on MgCl2(THF)2 was studied and the results were compared to those obtained for similar titanium catalysts. It was confirmed that the dependencies of the transfer reaction on the hydrogen concentration are a half‐order in all investigated systems. However, the transition metal of the catalytic site affects the ratio of the transfer rate with hydrogen to the propagation rate (ktr,H/kp) and the results showed that hydrogen is a more effective agent of polyethylene molecular weight control in vanadium‐based systems as compared to the titanium catalyst.

First Observation of Multiply Charged Vanadium Clusters in a Penning Trap

1997

Reductions of M{N(SiMe3)2}3 (M = V, Cr, Fe): Terminal and Bridging Low-Valent First-Row Transition Metal Hydrido Complexes and “Metallo-Transaminatio…

2021

The reaction of the vanadium(III) tris(silylamide) V{N(SiMe3)2}3 with LiAlH4 in diethyl ether gives the highly unstable mixed-metal polyhydride [V(μ2-H)6[Al{N(SiMe3)2}2]3][Li(OEt2)3] (1), which was structurally characterized. Alternatively, performing the same reaction in the presence of 12-crown-4 affords a rare example of a structurally verified vanadium terminal hydride complex, [VH{N(SiMe3)2}3][Li(12-crown-4)2] (2). The corresponding deuteride 2D was also prepared using LiAlD4. In contrast, no hydride complexes were isolated by reaction of M{N(SiMe3)2}3 (M = Cr, Fe) with LiAlH4 and 12-crown-4. Instead, these reactions afforded the anionic metal(II) complexes [M{N(SiMe3)2}3][Li(12-crown-…