Search results for "MANGANESE"

FIA-spectrophotometric determination of N-substituted phenothiazine derivatives by oxidation with a solid-phase reactor of manganese dioxide incorpor…

1995

Abstract The determination of several N -substituted phenothiazine derivatives was carried out by the reaction of the drug with managanese dioxide entrapped in a polymeric material in a packed-bed reactor; the oxidized drug was monitored at λ max . The calibration graph is linear over the range 5–50 μg/ml of phenothiazine derivatives with a relative standard deviation of 0.5–1% (at 10 μg/ml) and sample throughput of 40–48 h −1 . The influence of foreign compounds was studied and the method was applied to the determination of six different phenothiazine derivatives in pharmaceutical formulations.

Electron Transfer, Linkage Isomerization, Bulk Magnetic Order, and Spin-Glass Behavior in the Iron Hexacyanomanganate Prussian Blue Analogue

1999

Ba and Ni speciation in a nodule of binary Mn oxide phase composition from Lake Baikal

2007

The partitioning and incorporation mechanism of Ni and Ba in a ferromanganese nodule from Lake Baikal were characterized by X-ray microfluorescence, microdiffraction, and absorption spectroscopy. Fe is speciated as goethite, and Mn as romanechite (psilomelane) and 10 A ˚ -vernadite (turbostratic buserite) with minor 7 A ˚ -vernadite (turbostratic birnessite). Barium is associated with romanechite and Ni with vernadite in distinct and irregularly distributed layers, and each type of Mn oxide is separated from the other type by goethite. The binary Mn oxide banding pattern is interpreted by a two-mode accretionary model, in which the variation in Ba flux induced by hydrothermal water pulses d…

Slow relaxation of the magnetization in a {CoIIIMnIII} heterometallic brick-wall network

2021

Abstract The use of the cyanide-bearing dicobalt(III) complex (PPh4)2[Co2III(μ−2,5-dpp)(CN)8] as a metalloligand towards [Mn(salen)(H2O)]ClO4 afforded the heterobimetallic two-dimensional compound of formula [{MnIII(salen)}2{(μ-NC)4Co2III(μ−2,5-dpp)(CN)4}]n (1) [PPh4+ = teraphenylphosphonium cation, 2,5-dpp = 2,5-bis(2-pyridyl)pyrazine and H2salen = N,N’-ethylenebis(salicylideneimine)] whose structure has been determined by single crystal X-ray diffraction. Compound 1 exhibits a neutral brick-wall structure, where each [Co2III(μ−2,5-dpp)(CN)8]2− unit adopts a tetrakis-monodentate bridging mode towards four {MnIII(salen)}+ fragments through four of its eight cyanide ligands. Each cobalt(III)…

A novel octacyanido dicobalt(iii) building block for the construction of heterometallic compounds

2019

The first bimetallic octacyanido complex of CoIII, (PPh4)2[Co2(μ-2,5-dpp)(CN)8] (1), was synthesized and used as a metalloligand with [Mn(MAC)(H2O)2]Cl2·4H2O to give a new {CoIIIMnII} heterometallic chain of formula [MnII(MAC)(μ-NC)2Co2III(μ-2,5-dpp)(CN)6]n·7nH2O (2) (PPh4+ = tetraphenylphosphonium cation; 2,5-dpp = 2,5-bis(2-pyridyl)pyrazine and MAC = 2,13-dimethyl-3,6,9,12,18-pentaazabicyclo-[12.3.1]octadeca-1(18),2,12,14,16-pentaene). Both compounds were characterized by single-crystal X-ray diffraction. Compound 1 contains a diamagnetic 2,5-dpp-bridged dicobalt(III) unit with four peripheral cyanide ligands at each cobalt center achieving a six-coordinate surrounding, the electroneutral…

Sulfur cycling and methanogenesis primarily drive microbial colonization of the highly sulfidic Urania deep hypersaline basin

2009

Urania basin in the deep Mediterranean Sea houses a lake that is >100 m deep, devoid of oxygen, 6 times more saline than seawater, and has very high levels of methane and particularly sulfide (up to 16 mM), making it among the most sulfidic water bodies on Earth. Along the depth profile there are 2 chemoclines, a steep one with the overlying oxic seawater, and another between anoxic brines of different density, where gradients of salinity, electron donors and acceptors occur. To identify and differentiate the microbes and processes contributing to the turnover of organic matter and sulfide along the water column, these chemoclines were sampled at a high resolution. Bacterial cell numbers…

Synthesis, X-ray structure and magnetic properties of the azido adducts of quadridentate Schiff base manganese(III) complexes

2004

Abstract Two new azido derivatives of quadridentate Schiff base manganese(III) complexes have been synthesized and characterized structurally and magnetically. X-ray structure analysis revealed that both complexes viz. [Mn2(L1)2(N3)2] (1) and [Mn2(L2)2(N3)2] (2), where H2L1=N,N′-(1,1-dimethylethylene)-bis-(salicylaldiimine) and H2L2=bis(o-hydroxyacetophenone)-ethylenediimine exist as phenoxo-bridged dimer. The magnetic susceptibility of the complexes has been measured in the 5–300 K range. At room temperature the MnIII ions in complexes 1 and 2 possess an S=4 ground state. The global magnetic interaction in complex 1 is found to be ferromagnetic, while for complex 2 it is anti-ferromagnetic.

Base Control of Electron-Transfer Reactions of Manganese(III) Porphyrins

2000

Homogeneous electron-transfer kinetics for the reduction of four different manganese(III) porphyrins using different reductants were examined in deaerated acetonitrile, and the resulting data were evaluated in light of the Marcus theory of electron transfer to determine electron-exchange rate constants between manganese(III) and manganese(II) porphyrins. The investigated compounds are represented as (P)MnCl, where P = the dianion of dodecaphenylporphyrin (DPPX; X = H20, Cl12H8, or F20) or tetraphenylporphyrin (TPP). The electron transfer from semiquinone radical anion derivatives to (P)MnIIICl leads to formation of the corresponding MnII complex, [(P)MnIICl]−. The electron-exchange rate con…

CCDC 132983: Experimental Crystal Structure Determination

2001

Related Article: M.Hernandez-Padilla, E.Chinea, S.Dominguez, A.Mederos, M.C.Munoz, F.Lloret|2000|Polyhedron|19|1175|doi:10.1016/S0277-5387(00)00362-4

CCDC 837872: Experimental Crystal Structure Determination

2013

Related Article: B.Macias, M.V.Villa, R.Lapresa, G.Alzuet, J.Hernandez-Gil, F.Sanz|2012|J.Inorg.Biochem.|115|64|doi:10.1016/j.jinorgbio.2012.05.019