Search results for "Metals"
showing 10 items of 2013 documents
Metal complexes of phenobarbituric acid. Chelating behavior of the phenobarbiturate ring. Anticonvulsant properties of the K2[Cu(N-methylphenobarbitu…
1992
Abstract Na2Ni(phenobarbiturato)4·3H2O, Na2Ni3(phenobarbiturato)2(OH)6·4H2O, and NaZn(phenobarbiturato)2(OH)·H2O derivatives were prepared from Ni(II) and Zn(II) and phenobarbital. The Na2Ni(phenobarbiturato)4·3H2O complex is diamagnetic and isostructural with the complex previously reported, Na2Cu(phenobarbiturato)4, suggesting a square-planar environment around the Ni(II) ion. The DMF solutions of this complex show the existence of two species. The EPR spectra of the Cu(II) doped complex show the hyperfine and superhyperfine structures. The covalence parameters α2, β2, and δ2 show a strong bonding in the equatorial plane and suggests the formation of a [CuN4] chromophore. The anticonvulsa…
Hybrid molecular magnets incorporating organic donors and other electroactive molecules
1999
Molecule-based bidimensional ferromagnets can be used as anionic hosts for electroactive molecules, with the aim of obtaining multiproperty materials exhibiting in addition to the cooperative magnetism other interesting properties according to the nature of the inserted molecules. In particular, hybrid molecular compounds containing conducting (TTF-type organic donors), bi-stable or non-linear optical species are reported.
Molecular hybrids formed by oxalate bridged dinuclear anions and organometallic cations
1999
Abstract The syntheses, magnetic properties and infrared spectra of a new series of molecular hybrids formed by association of two magnetic sublattices: (i) oxalate bridged dinuclear anions [V 2 O 2 (ox)(NCS) 6 ] 4− and [M′M′'(ox)(NCS) 8 ] 4 ( M′= Fe III , Cr III ; M′' - Fe III , Cr III ; ox 2 = C 2 O 4 2 and (ii) decamethylferrocenium organometallic cation are presented. The crystal structure of [Fe(Cp * ) 2 ][(C 2 H 5 ) 4 N] 2 [V 2 O 2 (ox)(NCS) 6 ] is also discussed.
Hybrid functional study of structural, electronic and magnetic properties of S-doped ZnO with and without neutral vacancy
2013
Abstract The structural and electronic properties of S-doped ZnO are investigated by density functional theory (DFT) and empirical pseudopotential method (EPM). Using the Heyd–Scuseria–Ernzerhof (HSE) hybrid functional with an adjusted mixing coefficient α , we obtain a good agreement on lattice parameters and band gap energy with the available experimental data. We have also investigate the Zn-vacancy effects on the electronic and magnetic properties of S-doped ZnO. Our calculations demonstrate that S impurity prefers to be close to the cation vacancy in the apical position. The magnetic analysis with the HSE functional shows a triplet state character with a total magnetic moment of 1.81 μ…
Coordination Complexes of a Neutral 1,2,4-Benzotriazinyl Radical Ligand: Synthesis, Molecular and Electronic Structures, andMagnetic Properties
2015
A series of d-block metal complexes of the recently reported coordinating neutral radical ligand 1-phenyl-3-(pyrid-2-yl)-1,4-dihydro-1,2,4-benzotriazin-4-yl (1) was synthesized. The investigated systems contain the benzotriazinyl radical 1 coordinated to a divalent metal cation, MnII, FeII, CoII, or NiII, with 1,1,1,5,5,5-hexafluoroacetylacetonato (hfac) as the auxiliary ligand of choice. The synthesized complexes were fully characterized by single-crystal X-ray diffraction, magnetic susceptibility measurements, and electronic structure calculations. The complexes [Mn(1)(hfac)2] and [Fe(1)(hfac)2] displayed antiferromagnetic coupling between the unpaired electrons of the ligand and the meta…
Geostatistical 3-dimensional integration of measurements of soil magnetic susceptibility.
2010
In soil magnetometry, two types of measurements are usually performed. The first type is measurements performed on the soil surface, frequently using an MS2D sensor. The second type includes measurements of magnetic susceptibility carried out in the soil profile, usually to a depth of about 30 cm. Up to now, such measurement results were analyzed separately. However, it is possible and advantageous to integrate these two types of measurements. The goal of the study was to integrate measurements of magnetic susceptibility performed on the soil surface and in the soil profile. More specifically, the goal was to obtain 3-dimensional spatial distributions of magnetic susceptibility of the topso…
Magnetoresistance studies of the ferromagnetic molecular metal (BEDT-TTF)3[MnCr(C2O4)3] under pressure
2003
(BEDT-TTF)3[MnCr(C2O4)3] is the first ferromagnetic molecular metal, in which organic layers of BEDT-TTF alternate with infinite layers of the bimetallic oxalate complex [MnCr(C2O4)3]-. While the bimetallic layer undergoes a magnetic phase transition into a canted ferromagnetic state at 5.5 K, the metallic character of the conductivity is not affected by the magnetic transition [Nature 408 (2000) 447]. We performed magnetoresistance measurements (B≤17 T) at low temperatures (T≥900 mK) and under hydrostatic pressures of up to 2.0 GPa. Oscillations in the magnetoresistance develop under pressure that can be interpreted as Shubnikov-de Haas oscillations, if an internal magnetic field is taken …
Gender as a key factor in trace metal and metalloid content of human scalp hair. A multi-site study
2016
This multi-site study discusses the content of metals and metalloids (MM) in scalp hair of children, living in different environmental contexts, with the purpose of verifying if hair level of some MM is distinctively gender-specific. A total of 943 hair samples (537 females and 406 males) from adolescents were analysed for their content of Al, As, Ba, Cd, Co, Cr, Cu, Li, Mn, Mo, Ni, Pb, Rb, Sb, Se, Sr, U, V and Zn. Elemental quantification was performed by ICP-MS. The obtained data identified different metal distributions in adolescent girls which exhibited significantly higher hair concentrations of some trace metals, especially Sr, Zn and Ni, than boys. On the base of the median value, hai…
Association between toenail scandium levels and risk of acute myocardial infarction in European men: the EURAMIC and Heavy Metals Study
2002
The association between scandium status and risk of acute myocardial infarction (MI) was examined in a multicentre case control study in 10 centres from Europe and Israel. Scandium in toenails was assessed in 684 cases and 724 controls less than 70 years of age. Mean concentrations of toenail scandium were 6.74 micro/kg in cases and 7.75 microg/kg in controls. Scandium among controls, adjusted for age and centre was positively associated with concentrations of lycopene and oleic acid in adipose tissue (P = 0.002 for both nutrients). Pearson correlations adjusted for age and centre were significant (P0.05) between scandium and lycopene (r = 0.08), zinc (r = 0.08), mercury (r = 0.18) and olei…
Coverage intervals for trace elements in human scalp hair are site specific.
2014
Coverage intervals for trace elements in human scalp hair commonly provide the basis for interpreting laboratory results and also in comparative decision-making processes regarding exposure risk assessment. This short communication documents, by some examples, that those computed for human hair are to be considered site specific, as they reflect local environmental conditions; also each geographic area has a typical profile of hair elemental composition of its inhabitants. Therefore, the levels of trace elements in hair are not strictly comparable between different areas of the world. This issue is particularly relevant when identification of anomalous environmental exposures are requested …