Search results for "MANGANESE"
showing 10 items of 666 documents
Microwave muffle furnace assisted decomposition of vegetable samples for flame atomic spectrometric determination of Ca, Mg, K, Fe, Mn and Zn
1992
Calcium, magnesium, potassium, iron, manganese and zinc can be accurately determined in vegetable samples by flame atomic absorption and flame emission spectrophotometry after a previous dry ashing of the sample in a microwave muffle furnace. This treatment is carried out in 45 min using a new accessory developed by us to obtain high temperatures on a domestic microwave oven. Sample ashes, obtained in the muffle, are diluted with nitric acid and the obtained slurry is introduced directly into an air-C2H2 flame for the analysis of Fe, Mn, and Zn, or injected into a double-channel FIA manifold to determine Ca, Mg and K. The obtained results agree with those certified and also with those obtai…
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…
Magnetism and EPR spectra of the two‐sublattice manganese chain Mn2(EDTA)⋅9H2O
1990
We report on the magnetic behavior and single‐crystal EPR spectra of the chain complex Mn2(EDTA)⋅9H2O characterized by two different alternating sites for the manganese ions. Magnetic susceptibility data are indicative of weak antiferromagnetic exchange interactions between the manganese ions, showing a maximum of about 3 K. This behavior can be accurately described on the basis of a Heisenberg chain model that assumes classical spins, giving J/k=−0.72 K and g=2.0. The EPR spectra are typically low dimensional, with an angular dependence of the linewidth of the type (3 cos2 θ−1)n (n=4/3 or 2). Nevertheless, such a behavior cannot be reproduced from a one‐dimensional model with dipolar broad…
Ferromagnetism in [Mn(Cp*) 2 ] + ‐Derived Complexes: the “Miraculous” Stacking in [Mn(Cp*) 2 ][Ni(dmit) 2 ]
2003
The synthesis and characterisation (X-ray structure and magnetism) of metal complexes (Ni, Au) with the [Mn(Cp*)2]+ cation and the dmit2− and dmid2− ligands are reported. [Mn(Cp*)2][Ni(dmit)2] (1) and [Mn(Cp*)2][Au(dmit)2] (2) exhibit the same structural arrangement, built on stacks of [Ni(dmit)2]− pairs separated by two [Mn(Cp*)2]+ cations, showing a ···D+D+A−A−D+D+A−A−··· motif. On the contrary, the dmid2− derivative [Mn(Cp*)2][Ni(dmid)2]·CH3CN (3) exhibits a totally different structure, built on mixed layers composed of one [Ni(dmid)2]− unit separated by two [Mn(Cp*)2]+ cations, showing a ···D+D+A−D+D+A−···motif. The layers are separated from each other by perpendicular [Ni(dmid)2]− unit…
Significant in vivo anti-inflammatory activity of Pytren4Q-Mn a superoxide dismutase 2 (SOD2) mimetic scorpiand-like Mn (II) complex.
2015
Background The clinical use of purified SOD enzymes has strong limitations due to their large molecular size, high production cost and immunogenicity. These limitations could be compensated by using instead synthetic SOD mimetic compounds of low molecular weight. Background/Methodology We have recently reported that two SOD mimetic compounds, the MnII complexes of the polyamines Pytren2Q and Pytren4Q, displayed high antioxidant activity in bacteria and yeast. Since frequently molecules with antioxidant properties or free-radical scavengers also have anti-inflammatory properties we have assessed the anti-inflammatory potential of Pytren2Q and Pytren4Q MnII complexes, in cultured macrophages …
Effects of manganese injected into rat nostrils: implications for in vivo functional study of olfaction using MEMRI.
2011
WOS: 000298212500007; International audience; Manganese-enhanced magnetic resonance imaging (MEMRI) is a powerful tool for visualizing neuronal pathways and mapping brain activity modulation. A potential drawback of MEMRI lies in the toxic effects of manganese (Mn), which also depend on its administration route. The aim of this study was to analyze the effects of Mn doses injected into the nostrils of rats on both olfactory perception and MRI contrast enhancement. For this purpose, doses in the range 0-8 μmol MnCl(2) were tested. Behavioral items were quantified with and without odor stimulation during the first 2 h following Mn injection. The MRI study was performed after 16 h of intermitt…
Foetal exposure to heavy metals and risk of atopic diseases in early childhood
2020
International audience; Background: Accumulating evidence suggests that in utero exposures can influence the development of the immune system and thus contribute to disease development. Studies investigating the association between prenatal exposures to heavy metals and atopic diseases, however, are scarce.Methods: Children from the EDEN birth cohort were prospectively followed up using parental questionnaires with validated questions on asthma, allergic rhinitis, eczema, and food allergy symptoms. The questionnaires were administered every 4 months during the children's first year, and then every year until the age of 5, with a final survey at the age of 8. Serum concentrations of lead (Pb…
m-Carboranylphosphinate as Versatile Building Blocks To Design all Inorganic Coordination Polymers
2017
The first examples of coordination polymers of manganese(II) and a nickel(II) complex with a purely inorganic carboranylphosphinate ligand are reported, together with its exhaustive characterization. X-ray analysis revealed 1D polymeric chains with carboranylphosphinate ligands bridging two manganese(II) centers. The reactivity of polymer 1 with water and Lewis bases has also been studied Thanks to MINECO (CTQ2015-66143-P, CTQ2010-16237 and SEV-2015-0496), Generalitat de Catalunya (2014/SGR/149), and COST CM1302. E.O. who is enrolled in the PhD program of the UAB thanks for FPU grant
Mn(IV) and Co(III)-complexes of –OH-rich ligands possessing O2N, O3N and O4N cores: syntheses, characterization and crystal structures
2003
Mn(IV) and Co(III) complexes of tridentate –OH–rich ligands possessing O2N, O3N and O4N donor sets were synthesized, characterized and their structures were established by single crystal X-ray diffraction, where the binding core is O4N2. In the structurally characterized complexes, the coordination geometry about the metal ion was found to be distorted octahedral.
Electrochemistry and Spectroelectrochemistry of Bismanganese Porphyrin-Corrole Dyads
2011
A series of homobimetallic manganese cofacial porphyrin-corrole dyads were synthesized and investigated as to their electrochemistry, spectroelectrochemistry, and ligand binding properties in nonaqueous media. Four dyads were investigated, each of which contained a Mn(III) corrole linked in a face-to-face arrangement with a Mn(III) porphyrin. The main difference between compounds in the series is the type of spacer, 9,9-dimethylxanthene, anthracene, dibenzofuran, or diphenylether, which determines the distance and interaction between the metallomacrocycles. Each redox process of the porphyrin-corrole dyads was assigned on the basis of spectroscopic and electrochemical data and by comparison…