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Chemiluminescence was observed from reactions with a Mn(IV) colloid generated by reduction of KMnO_4 with Na_2S_2O_3. Due to the limited stability of the colloid under acidic conditions and the poor reproducibility of the chemilum...
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Chemiluminescence was observed from reactions with a Mn(IV) colloid generated by reduction of KMnO_4 with Na_2S_2O_3. Due to the limited stability of the colloid under acidic conditions and the poor reproducibility of the chemiluminescence signal when the reagent was prepared by published methods, an in situ (on-line) method of preparation utilising flow injection analysis methodology was developed. This approach provided superior emission intensities to the conventional Mn(IV) reagent, although less enhancement was obtained from the addition of formaldehyde. The selectivity of the reagent was 'tuned' towards specific classes of analyte through convenient modification of reaction conditions. Contrary to some previous reports, we attribute this chemiluminescence to the formation of an electronically excited Mn(II) species, based on direct comparison of the spectral distribution with that of other chemiluminescence reactions.
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Manganese(II) acetate tetrahydrate reacts with tris(hydroxymethyl)-N-(2-oxo-I-naphthylideneamino)methane (ohthH4) in methanolic solution in (1 : 2.5) molar ratio yielding the complex,bis[tris(hydroxymethyl)-N-(2-oxo-1-naphthyIiden...
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Manganese(II) acetate tetrahydrate reacts with tris(hydroxymethyl)-N-(2-oxo-I-naphthylideneamino)methane (ohthH4) in methanolic solution in (1 : 2.5) molar ratio yielding the complex,bis[tris(hydroxymethyl)-N-(2-oxo-1-naphthyIideneaniino)methane]manganese(IV),[Mn~(IV)(ohthH2)2] and its reaction with other oxygen and nitrogen donors results the complexes of manganese(IV) of the compositions [Mn~(IV)(ohthH)(sal)] (2) and [Mn~(IV)(ohthH)(sal)(A)] [A = pyridine (3),3-picoline (4)].The complexes have been characterized by elemental analysis,molar conductance,magnetic moment,cyclic voltammetry,electronic,ESR and infrared spectral studies.On the basis of UV,IR and NMR spectral evidences,the ligand,tris(hydroxymethyl)-N-(2-hydroxy-1-naphthylideneamino)methane,have been shown to exist predominately in the quinoneamine form and acting as dibasic tridentate,tribasic tetradentate and tribasic tridentate in these complexes.
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A historical review of the development of mangamese(IV) chemistry and its application in analytcal chemistry is presented. A brief presentation of the presence and improtance of mangamese(IV) in other areas of chemistry is also given.
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? RJPT All right reserved.Highly sensitive method for separation and determination of micro amount of oxyanion for Mo(VI), W(VI), and Mn(VII) was performed. It has been done after formation of ion pair association complexes with S...
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? RJPT All right reserved.Highly sensitive method for separation and determination of micro amount of oxyanion for Mo(VI), W(VI), and Mn(VII) was performed. It has been done after formation of ion pair association complexes with Safranin as complexing agent including joint cloud point extraction with liquid ion exchange methods in the presence of non-ionic surfactant Triton X–100. The study is based on the values of wavelength of maximum absorbance, λmax= 536, 533, and 534nm respectively. Optimal conditions have been pinpointed high extraction efficiency needed for HCl concentration (1.0, 1.0 and 0.6) M respectively in the presence of 50μg metal ions in 10mL aqueous solutions. Besides, the stoichiometry of probable extracted structure of ion pair complexes was1:1:1 for all extracted complex, in addition to other effective parameters on extraction efficiency in this study.
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The quest to synthesis advanced ceramic materials with enhanced density and mechanical properties have prompted the addition of multiwall carbon nanotubes (MWCNTs) and manganese oxide to titania (TiO_2) matrix. In this research, T...
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The quest to synthesis advanced ceramic materials with enhanced density and mechanical properties have prompted the addition of multiwall carbon nanotubes (MWCNTs) and manganese oxide to titania (TiO_2) matrix. In this research, TiO_2 based composites comprising of 0.5,1.0 and 1.5 wt. % MWCNTs and 5 wt. % manganese oxide (MnO_2) was synthesized via spark plasma sintering (SPS) technique. Prior to the consolidation of the ceramic composites, the starting powders were milled using ball milling technique, and the dispersibility and structural evolution of the MWCNTs were investigated. The milled powders were consolidated at 1200°C under a compressive pressure of 25 MPa using a holding time and heating rate of 5 min and 50 °C/min respectively. Furthermore, the influence of different fraction of MWCNTs and MnO_2 in the milled powders and sintered composites were evaluated using transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) technique and Raman spectroscopy. The roles of MWCNTs and the presence of MnO_2on the sintering, densification and microhardness of the sintered composites were also explored. The morphology, XRD patterns and Raman spectra of the milled powders indicated that the presence of MnO_2 influenced the dispersibility and structural integrity of the nanotubes in the composites. In addition, the presence of MnO_2 improved the densification and microhardness of the composites. The microhardness values were in the range of 11.5 -13.7 GPa, which improved with the addition of MWCNTs. Whereas, higher concentrations of MWCNTs result in decrease in the densification of the ceramic composites with relative density ranging from 98 to 99%.
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MnO2 surface layers and the addition of Mn-3(PO4)(2) through the gas phase have an advantageous combined effect on the thermal oxidation of InP, increasing the growth rate of the oxide film, ensuring rapid chemical binding of the ...
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MnO2 surface layers and the addition of Mn-3(PO4)(2) through the gas phase have an advantageous combined effect on the thermal oxidation of InP, increasing the growth rate of the oxide film, ensuring rapid chemical binding of the indium, blocking its diffusion into the film, and activating phosphate formation processes, which leads to the formation of dielectric nanofilms with resistivity as high as 10(10) Omega cm.
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Two extended Waugh-type polyoxometalates compounds, (NH4)(4)Na-2[MnMo9O32](center dot)6H(2)O (1) and (NH4)(2)Na-2[{CU(H2O)(4)} (MnMo9O32)](center dot)5H(2)O (2) have been synthesized and characterized. Both of the left-handed and ...
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Two extended Waugh-type polyoxometalates compounds, (NH4)(4)Na-2[MnMo9O32](center dot)6H(2)O (1) and (NH4)(2)Na-2[{CU(H2O)(4)} (MnMo9O32)](center dot)5H(2)O (2) have been synthesized and characterized. Both of the left-handed and right-handed [MnMo9O32](6-) polyanions enantiomers can be observed in compounds 1 and 2. In compound 1, the homochiral [MnMo9O32](6-) polyanions enantiomers are linked by sodium ions to form two kinds of alternately arranged 2D polymeric sheets, which are further stacked into a 3D framework. In compound 2, the homochiral [MnMo9O32](6-) polyanions enantiomers are linked by [(H2O)(2)Cu(mu(2)-H2O)(2)Na(H2O)(2)](3+) bimetal aggregates to form two kinds of alternately arranged zigzag chains, which are further weaved into a 2D polymeric sheet by sodium ions. In addition, the influence of the synthesis conditions has also been studied.
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Although potassium permanganate [Mn(VII)] has been used extensively as a chemiluminescence reagent for many decades, other manganese-based oxidants have only recently been explored for this purpose. There is strong evidence to sug...
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Although potassium permanganate [Mn(VII)] has been used extensively as a chemiluminescence reagent for many decades, other manganese-based oxidants have only recently been explored for this purpose. There is strong evidence to suggest that, like permanganate, man-ganese(III) and manganese(IV) oxidants react with many molecules to produce an excited manganese(II) species that emits light. However, these reagents differ markedly in terms of selectivity, and possess characteristics that provide new avenues for detection, such as the immobilisation of solid manganese dioxide, the production of 'soluble' manganese(IV) nanoparticles, and the electrochemical generation of manganese(III). In this review we examine the emergence of these alternative manganese oxidants as chemiluminescence reagents.
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One-dimensional manganese (IV) oxide (MnO_2) (～20 nm in average diameter) were synthesized by cathodic electrodeposition and heat treatment. The mechanism of electrodeposition and nanowire formation were discussed. The product wa...
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One-dimensional manganese (IV) oxide (MnO_2) (～20 nm in average diameter) were synthesized by cathodic electrodeposition and heat treatment. The mechanism of electrodeposition and nanowire formation were discussed. The product was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and Fourier transform infrared (FT-IR). Nanowires with varying lengths and diameters were found in TEM and SEM images of the sample. The results of N_2 adsorption-desorption analysis indicated that the BET surface area of the MnO_2 nanowires was 157 m~2g~(-1) and the pore size distributions were 2.5 and 4.5 nm. The electrochemical performances of the prepared MnO_2 as an electrode material for supercapacitors were evaluated by cyclic voltammetry and galvanostatic charge/discharge measurements in a solution of 0.5 M Na_2SO_4. The higher specific capacitance of 318 F g~(-1) and good capacity retention of 86% were achieved after 1000 charge-discharge cycles had been observed for the MnO _2 nanowires electrode.
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