Search results for "ammonium"
showing 10 items of 1070 documents
CCDC 919043: Experimental Crystal Structure Determination
2013
Related Article: María Castellano, Wdeson P. Barros, Alvaro Acosta, Miguel Julve, Francesc Lloret, Yanling Li, Yves Journaux, Giovanni De Munno, Donatella Armentano, Rafael Ruiz-García, Joan Cano|2014|Chem.-Eur.J.|20|13965|doi:10.1002/chem.201403987
The reduction of tris-dithiolene complexes of molybdenum(vi) and tungsten(vi) by hydroxide ion: kinetics and mechanism
2004
The kinetic study of the spontaneous reduction of some neutral tris-dithiolene complexes [ML3] of molybdenum(VI) and tungsten(VI), (L = S2C6H42−, S2C6H3CH32− and S2C2(CH3)22−; M = Mo or W) by tetrabutylammonium hydroxide in tetrahydrofuran-water solutions demonstrates that OH− is an effective reductant. Their reduction is fast, clean and quantitative. Depending upon both the molar ratio in which the reagents are mixed and the amount of water present, one- or two-electron reductions of these tris-dithiolene complexes were observed. If Bu4NOH is present in low concentration or/and at high concentrations of water, the total transformation of the neutral M(VI) complex into the monoanionic M(V) …
Capillary electrophoretic and nuclear magnetic resonance studies of interactions between halophenols and ionic liquid or tetraalkylammonium cations.
2003
Aqueous capillary electrophoretic studies were performed to investigate interactions between halophenols and 1-ethyl-3-methylimidazolium tetrafluoroborate or tetraethylammonium tetrafluoroborate electrolytes. In both cases, increased halogen size correlated with increased affinity for the electrolyte cation. For isomers, the ortho substituted isomer exhibited higher affinity than the para isomer. Irreproducible CE results for analyte pairs in the presence of the ionic liquid stimulated investigations of the interactions between halophenols as well as with the cations of the electrolyte. These interactions were explored by proton and fluorine one-dimensional NMR. The NMR results indicated di…
Dimeric Capsules Formed by Tetra-CMPO Derivatives of (Thia)Calix[4]arenes
2010
Thiacalix[4]arene 2, calix[4]arene 3 a and its tetraether fixed in the cone conformation 3 b form homo- and heterodimeric capsules in apolar solvents, which are held together by a seam of NH⋅⋅⋅O=P hydrogen bonds between carbamoylmethyl phospine oxide functions attached to their wide rim. Their internal volume of ∼370 A3 requires the inclusion of a suitable guest. Although neutral molecules such as adamantane (derivatives) or tetraethylammonium cations form kinetically stable complexes (1H- and 31P-time scale), the included solvent is rapidly exchanged. The internal mobility of the included tetraethylammonium cation is distinctly higher (ΔG=42.5 and 49.7 kJ mol−1 for 3 a and 3 b) than that f…
CCDC 218498: Experimental Crystal Structure Determination
2003
Related Article: M.Makinen, P.Vainiotalo, M.Nissinen, K.Rissanen|2003|J.Am.Soc.Mass.Spectrom.|14|143|doi:10.1016/S1044-0305(02)00863-2
CCDC 645088: Experimental Crystal Structure Determination
2007
Related Article: M.Cametti, M.Nissinen, A.D.Cort, L.Mandolini, K.Rissanen|2007|J.Am.Chem.Soc.|129|3641|doi:10.1021/ja068561z
CCDC 293967: Experimental Crystal Structure Determination
2006
Related Article: R.Artali, G.Bombieri, N.Bertazzi|2005|Acta Crystallogr.,Sect.E:Struct.Rep.Online|61|m2733|doi:10.1107/S1600536805038870
Characterization of the Oxidation of Magnetite Nanoparticles during Their Synthesis by Different Structural Analysis Techniques
2020
Water colloidal solutions of iron oxide nanoparticles coated with tetramethylammonium hydroxide were synthesized by co-precipitation methods. Dimensional analyses were accomplished by transmission ...
On-line determination of bipyridylium herbicides in water by HPLC
1997
Selective on-line solid phase extraction (SPE) and liquid chromatography determination (HPLC) of diquat, paraquat and difenzoquat from environmental water samples has been accomplished with Graphitized Carbon Black (GCB) as both extraction and analytical columns. The method involved passing of 50 mL of water through a cartridge filled with Carbograph. In the elution step, the herbicides were transferred from the cartridge to the analytical column (Hypercarb) by mean of a gradient of pH 3 aqueous solution of tetramethylammonium hydroxide (TMAOH) and ammonium sulphate and methanol. Hypercarb columns were found to give a low probability of false positives for bypiridylium herbicides and are ve…
Characterization of acrylic resins used for restoration of artworks by pyrolysis-silylation-gas chromatography/mass spectrometry with hexamethyldisil…
2006
A procedure based on the technique of the pyrolysis-GC/MS has been applied, in this work, in order to determine the composition of synthetic acrylic resins employed in artworks. The method is based on the on line derivatization of these resins using hexamethyldisilazane (HMDS). Results obtained have been compared with those others from direct pyrolysis and in situ thermally assisted hydrolysis and methylation with tetramethylammonium hydroxide (TMAH). Sensitivity using HMDS as derivatising reagent is found similar to that from direct pyrolysis and methylation with TMAH. Better resolution of the most representative peaks has been also obtained. Additionally, this method reduces the formation…