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The preparation of {[(MeO)3P]n·AgO 3SCH3} (n = 1, 2a; n = 2, 2b) is described. The molecular structure of 2a was determined by using X-ray single crystal analysis. Complex 2a contains an Ag4 rectangular make-up, the centroid of w...
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The preparation of {[(MeO)3P]n·AgO 3SCH3} (n = 1, 2a; n = 2, 2b) is described. The molecular structure of 2a was determined by using X-ray single crystal analysis. Complex 2a contains an Ag4 rectangular make-up, the centroid of which constitutes an inversion center. Complex 2b was used as precursor in the deposition of silver films using metal organic chemical vapor deposition (MOCVD) technique for the first time. The silver films obtained were characterized using scanning electron microscopy (SEM) and energy-dispersion X-ray (EDX) analysis.
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The conditions for stable silver nanoparticles dispersions synthesis from organic sulfonic acids in an anhydrous medium of ethylene glycol and its methyl ester were studied. Ascorbic acid and potassium citrate were used as reducing agents.
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Dendritic silver particles (DSPs) were synthesized by a facile electrolysis method based on the self-made silver methanesul-fonic as an electrolyte and the surface of DSPs was coated with methyl-1H-benzotriazole to prepare the sur...
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Dendritic silver particles (DSPs) were synthesized by a facile electrolysis method based on the self-made silver methanesul-fonic as an electrolyte and the surface of DSPs was coated with methyl-1H-benzotriazole to prepare the surface-modified DSPs. Dendritic feature with a trunk and nano-branches is confirmed by scanning electron microscopy. At temperatures above 200°C, the sintering phenomenon is discovered at the nano- branches of DSPs. As the prepared DSPs are introduced into the commercial micron-scale silver particles-based electrically conductive adhesives (ECAs), the electrical resistivity can be significantly reduced to 5.63×10~5 Ω cm, which is superior to the traditional conductive adhesives derived from the pure micron-scale silver particles, implying the high application value of DSPs for high-performance conductive adhesive.
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A series of experiments for obtaining modified with silver nanoparticles ultra-high molecular weight polyethylene (UHMWPE) is done. Optimal precursors are silver trifluoroacetate, silver nitrate and silver methanesulfonate. Three ...
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A series of experiments for obtaining modified with silver nanoparticles ultra-high molecular weight polyethylene (UHMWPE) is done. Optimal precursors are silver trifluoroacetate, silver nitrate and silver methanesulfonate. Three variants of UHMWPE modification is studied: 1) the polyol synthesis, 2) polymer processing silver nanoparticle colloid and 3) reduction of silver salt solution in the UHMWPE polymer matrix. It is found that the last method is optimal. The specific surface of obtained nanoparticles is 7.1-7.6 m~2/g and the size varies in the range of 60-110 nm. The antibacterial activity of the composite samples to ￡ Coli and S. Aureus is studied. Inhibition of bacterial growth occurs at the level 10~4 cfu/ml and 10~6 cfu/ml respectively.
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Silver refining is traditionally done by casting raw silver anodes and a following electrolytic refining step in a nitrate system (Moebius electrolysis). However, the disadvantages of this technology like the necessity of scrapers...
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Silver refining is traditionally done by casting raw silver anodes and a following electrolytic refining step in a nitrate system (Moebius electrolysis). However, the disadvantages of this technology like the necessity of scrapers, the possible redissolution of deposited silver and the possible production of harmful NOx gases give a strong impetus to develop an alternative technology for the refining of raw silver. Due to the high solubility of its silver salts and its less environmentally harmful character in comparison to nitric acid, methanesulfonic acid (MSA) is an attractive option as base chemical for silver refining and winning. In this paper the leaching of raw silver with MSA is investigated. The processed raw silver granules consist of approx. 93 % silver and have a diameter size range of 100 % < 1 mm. Laboratory scale agitation leaching experiments are conducted for five hours under strongly acidic conditions with hydrogen peroxide as oxidation agent. Leaching parameters like solid to liquid ratio and hydrogen peroxide dosage are varied. Silver leaching yields of about 95 % and high selectivity regarding the leaching of palladium are obtained with a solid start concentration of 550 g/L and a three times stoichiometric H2O2 dosage. Furthermore, characterization of the leaching residues was done. The experimental results demonstrate the suitability of the MSA/H2O2 leaching system as an approach towards a new technology of raw silver refining.
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For the last 120 years the Mobius electrolysis in nitric acid system has been the most widely used technology for silver electrorefining in Europe. The Institute for Nonferrous Metallurgy and Purest Materials lately conducted seve...
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For the last 120 years the Mobius electrolysis in nitric acid system has been the most widely used technology for silver electrorefining in Europe. The Institute for Nonferrous Metallurgy and Purest Materials lately conducted several electrolysis experiments to examine the suitability of methanesulfonic acid (MSA) as an alternative electrolyte for silver refining. In the electrolysis tests temperature, silver concentration, free acid concentration, current density and the type of additives were varied. Basic electrolysis specifications were measured during the experiments and afterwards the deposited silver cathodes were chemically and optically examined. The electrolysis tests showed that compact silver deposition is possible up to high current densities. By varying the process parameters relatively smooth surfaces even at high current densities could be produced. The results showed that low temperatures, a silver concentration in the range of 80 to 150 g/L and a relatively high free acid concentration improved the quality of the cathodes. The tests proved that methanesulfonic acid is an interesting alternative to nitric acid for the electrorefining of silver, particularly if process stability, energy consumption and complexity of the cell design are considered.
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(Protamine-pectin)(4) and (protamine-pectin)8 microcapsules and those containing also Ag nanoparticles were formed using the polyelectrolyte layer-by-layer (LbL) self-assembly method. The efficiency of imatinib methanesulfonate en...
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(Protamine-pectin)(4) and (protamine-pectin)8 microcapsules and those containing also Ag nanoparticles were formed using the polyelectrolyte layer-by-layer (LbL) self-assembly method. The efficiency of imatinib methanesulfonate encapsulation in the microcapsules was 85.0 +/- 6.0%. Microcapsules containing up to 50 mass% imatinib methanesulfonate and providing a prolonged release profile of the encapsulated drug were prepared. Encapsulation of imatinib in microcapsules increased its cytostatic activity (IC50 values reduced by 1.2 - 3.5 times) as compared with the free drug on the Molt-4, K-562, and KG-1 cell lines.
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The reaction of Ag(CH3SO3) with PPh3 gave the compound [Ag(CH3SO3)(PPh3)(2)] (I) and the reaction of Ag(CH3SO3) with PPh3 and 1,2-bis(4-pyridyl)ethane (Dpe) affords the mixed complex [Ag(CH3SO3)(PPh3)(Dpe)] (II). The crystal struc...
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The reaction of Ag(CH3SO3) with PPh3 gave the compound [Ag(CH3SO3)(PPh3)(2)] (I) and the reaction of Ag(CH3SO3) with PPh3 and 1,2-bis(4-pyridyl)ethane (Dpe) affords the mixed complex [Ag(CH3SO3)(PPh3)(Dpe)] (II). The crystal structures of I and II were determined by X-ray diffraction (CIF file CCDC no. 1563357 (for I)). In I, the centrosymmetric binuclear complex [Ag(CH3SO3)-(PPh3)(2)](2) is formed. The Ag atom has a distorted tetrahedral coordination composed of two bidentate bridging O atoms of the sulfonate anion and two P atoms of two PPh3 ligands. The structure of II is based on the centrosymmetric binuclear molecule with two bridging Dpe ligands between two [Ag(CH3SO3)(PPh3)] complexes. The O atoms of the methanesulfonate ion are statistically disordered, which induces a considerable distortion of the silver polyhedron with C.N. 5. Both compounds tend to emit in the blue and green regions of the PL spectra.
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Six organophosphine/phosphite stabilized silver(I) methanesulfonates of type [LnAgO3SCH3] (L=Ph3P, n = 1, 2a; n = 2, 2b; n = 3, 2c; L = (EtO)(3)P; n = 1, 2d; n = 2, 2e; n = 3, 2f) were synthesized by the reaction of silver methane...
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Six organophosphine/phosphite stabilized silver(I) methanesulfonates of type [LnAgO3SCH3] (L=Ph3P, n = 1, 2a; n = 2, 2b; n = 3, 2c; L = (EtO)(3)P; n = 1, 2d; n = 2, 2e; n = 3, 2f) were synthesized by the reaction of silver methanesulfonates with triphenylphosphine or triethylphosphite in dichloromethane under nitrogen atmosphere. These complexes were obtained in high yields and characterized by elemental analysis, H-1-, C-13{H} NMR, IR spectroscopy and thermogravimetric analysis (TGA), respectively. X-ray single crystal analysis reveals that complex 2a is a tetramer [ph(3)PAgO(3)SCH(3)](4) and complex 2b is a monomer. The thermal stability of 2a has been Studied by applying thermogravimetric analysis. It starts to decompose between 50 and 440 degrees C in a three-step process. The final residue (Ag) is about 20.50%. (C) 2008 Elsevier Ltd. All rights reserved.
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