Search results for "Oxide"
showing 10 items of 6424 documents
Ejection of molecules from WO3 under ion bombardment: the role of the crystal structure
1992
Abstract Emission of molecular ions from WO 3 and Na x WO 3 was studied by SIMS. It was found that the phenomenon of ejection of molecules had not arisen from specific WO bond lengths and strengths in tungsten trioxide.
Crystal and molecular structures of hexaaquazinc(II)isonicotinate n-oxide and catena-diaquabis-μ-(isonicotinato n-oxide)cadmium(II)
1984
Abstract [Zn(H2O)6](N-inicO)2 is an ionic compound made up of hexaaqua metal cations and isonicotinate N-oxide anions. It forms an isomorphic series with the corresponding Mg2+, Fe2+, Co2+ and Ni2+ compounds. In [Cd(N-inicO)2(H2O)2]n complex, coordination takes place through the NO oxygen and one of the (COO) oxygens with ligand forming thus a double bridge between Cd2+ ions. The structure is an endless chain stretching diagonally through the unit cell. The coordination polyhedron in both compounds is almost undistorted octahedron.
Electrochemical study on (NN)Fe3 (CO)9 ((NN) = 2,3-diazanorbornene) and related compounds. A new example of activation of carbon monoxide replaceme…
1985
Abstract The compound (NN)Fe 3 (CO) 9 ( 1 ) in tetrahydrofuran undergoes two reversible one-electron reduction processes in cyclic voltammetry at the platinum electrode. A rapid electron transfer-catalyzed reaction occurs when 1 is reduced in the presence of L (L = P(OMe) 3 ) and this gives (NN)Fe 3 (CO) 8 L ( 2 ), quantitatively. Only an electron-induced nucleophilic substitution is observed for compound 2 under the same conditions, yielding (NN)Fe 3 (CO) 7 L 2 , which undergoes a similar reaction but with much lower efficiency, to give (NN)Fe 3 (CO) 6 L 3 .
Environmental analysis of chlorinated aromatic thioethers, sulphoxides and sulphones
1993
Abstract Chlorinated aromatic thioethers discussed here are polychlorinated dibenzothiophenes, thianthrenes and diphenylsulphides. Relatively little is known about their occurrence, behaviour and fate in the environment. Polychlorinated dibenzothiophenes and diphenylsulphides have recently been found to be formed in waste combustion and analysed in pulp mill effluents. Chlorinated sulphoxides and sulphones are usually metabolites or oxidation products of different chlorinated aromatic compounds. Different gas chromatographic-mass spectrometric techniques are used in the analysis of the chlorinated thioethers. The sulphoxides and sulphones, because of their higher polarity, can be isolated f…
Single-pump bi-dimensional LC applied to the characterization of derivatized fatty alcohol ethoxylates.
2010
A column selection valve and a 6-port 2-position injection valve were combined to implement bi-dimensional LC in a system driven by a single pump. The system was applied to the separation of linear fatty alcohol ethoxylates with 12-18 carbon atoms in the hydrocarbon moiety, previous derivatization with diphenic anhydride. Separation on the first separation dimension (C(1)) was carried out with a propyl-diol column and an acetonitrile/aqueous ammonium acetate gradient. Fatty alcohol ethoxylate hydrocarbon series (oligomers with the same number of carbon atoms in the alkyl chain but differing in the number of ethylene oxide units) were resolved without distinguishing the oligomers within the …
Modeling of Amino Acid Electrodiffusion through Fixed Charge Membranes
2001
Abstract We study theoretically the electrodiffusion of amino acids through fixed charge membranes, calculating the ionic fractions of the amino acid in the membrane as well as its total flux as a function of the relevant experimental parameters (amino acid concentration, salt concentration, and pH of the external solution; membrane fixed charge concentration; and amino acid membrane/solution partition coefficients) under different experimental conditions (symport vs antiport transport, uphill transport, etc.). The theoretical approach employed is based on the Nernst–Planck flux equations in the (Goldman) constant electric field assumption and considers all the species present in the system…
Structurally bound lipids in peat humic acids
2001
Humic acids from highly decomposed peat were subjected to oxidation with alkaline cupric oxide (CuO) at 170°C (single oxidation). Oxidation products were isolated as three fractions, oxidized humic acids, fulvic acids and lipophilic compounds. Isolated oxidized humic acids were subsequently re-oxidized (sequential oxidation) under the same conditions, and released lipophilic compounds were isolated. Lipids released during single and sequential oxidations were determined using capillary gas chromatography and mass spectrometry. Identified compounds accounted for 3.3 and 0.12 wt.% of humic acid content, respectively. Lipid profiles of lipophilic fractions released during single and sequential…
New acetylenes fromChrysanthemum coronarium L.
1990
The investigation of the aerial parts of Chrysanthemum coronarium yielded, in addition to several known compounds, two new acetylenic sulfoxides 9 and 10, and a new thiophene spiroacetal enol ether 11. Their structures were deduced by spectroscopic and chemical methods.
Electropolymerization of N-methylanthranilic acid and spectroelectrochemical characterization of the formed film
2009
Abstract The electropolymerization of N-methylanthranilic acid (NMAA) is reported in this paper. The monomer is substituted both at ortho- and N-position and, to the best of our knowledge, it has not been previously electropolymerized. Electropolymerization of NMAA was done on glassy carbon and optically transparent (indium) tin oxide electrodes. The obtained films, which are probably of an oligomeric nature (oligoNMMA), were characterized with cyclic voltammetry (CV), in situ UV–vis and Raman spectroscopy, ex situ FTIR spectroscopy and scanning electron microscopy (SEM). Our results show that NMAA can be electropolymerized as thin films in 1.0 M HClO4, but the oxidation and reduction peak …
Electrochromic Performances of Poly(Azure A) Films from Digital Video-Electrochemistry (DVEC)
2020
Poly(Azure A) (PAA) films doped with sodium dodecyl sulfate (SDS) were grown on transparent indium tin oxide (ITO) glass substrates by cyclic voltammetry. The electrochromism of PAA was investigated by digital video-electrochemistry (DVEC). DVEC consists of the acquisition of sequential digital images during the electro-stimulated changes of PAA color. The evolution of red, green, and blue (R, G, B) colors intensity (I) of analyzed pixels provides enough sensitivity to detect changes of some nmol cm−2 of electroactive centers. Besides, the different time evolution of these color intensities can serve to discern among different electroactive centers activated in the polymer. For the first ti…