Chelate von ß-Dicarbonylverbindungen und ihren Derivaten. 60. Zur Komplexbildung von 2-Acylthioacetamiden

Chelates of ß-Dicarbonyl Compounds and their Derivatives. 60. Coordination Ability of 2-Acylthioacetamides A series of metal chelates with N-substituted and N, N-disubstituted 2-acylthioacetamides was synthesized in the solid state, and the coordination site was studied. Acid constants and complex stability constants determined in dioxane-water mixture were used to characterize the coordination ability of the ligands. In comparison with nickel the zinc chelates show a higher stability. The formation of pyridine adducts of the nickel chelates was discussed in their relation to complex stability and the influence of substituents in the ligands.     

Liquid—liquid extraction of transition metals with acylthioacetamides

The extraction behaviour of acylthioacetamides, R¹—CO—CH₂—CS—NR²R³, was studied for a series of transition metals. The highest distribution ratios were obtained with benzoylthioacetanilide. Complexes with acylthioacetamides which were completely substituted on the amide group were extracted slowly. The ranking of the extraction characteristics is related to the different pK_a values of the compounds used. Polymerization and solvation reactions can be excluded at metal concentrations of ? 10^-3 mol dm^-3 and extractant concentrations of ?10^-1 mol dm^-3, respectively. Decreasing extractability, Cu(II) > Zn(II) > Ni(II) > Co(II) > Cd(II), corresponds to the stability constants of the extracted metal chelates. Iron(III) cannot be extracted at pH ?3; Hg(II), Pd(II), and Au(III) are extracted readily over a reasonably wide pH range. The different extraction constants for zinc(II) and cadmium(II) permit an effective separation of these ions with benzoylthioacetanilide.     

High energy improved scalar quantum field theory from noncommutative geometry without UV/IR-mixing

We consider an interacting scalar quantum field theory on noncommutative Euclidean space. We implement a family of noncommutative deformations, which – in contrast to the well known Moyal–Weyl deformation – lead to a theory with modified kinetic term, while all local potentials are unaffected by the deformation. We show that our models, in particular, include propagators with anisotropic scaling z=2$z=2$ in the ultraviolet (UV). For a Φ⁴${\Phi }^4$-theory on our noncommutative space we obtain an improved UV behaviour at the one-loop level and the absence of UV/IR-mixing and of the Landau pole.     

The effect of magnetic fields on the electrodeposition of iron

The effect of a uniform magnetic field with flux density up to 1 T on the electrodeposition of Fe from sulphate electrolyte has been investigated under different field configurations relative to the electrode surface. Voltammetric and chronoamperometric experiments have been carried out coupled with an electrochemical quartz crystal microbalance for in situ mass change measurements. The structure and morphology of the deposited films were determined by scanning electron microscopy, atomic force microscopy and X-ray diffraction measurements. Results show that, when the magnetic field is applied parallel to the electrode surface, the limiting current density and the deposition rate are increased due to the magnetohydrodynamic effect. The nucleation process is also affected in parallel configuration; the current density of the maximum on the chronoamperograms is decreased, and an additional nucleation step might be observed. This effect is attributed to the hydrodynamic response of the electrochemical system. No significant influence on the electrochemical reaction was observed when a magnetic field was applied perpendicular to the electrode. But in this configuration, the morphology of deposited layers is changed by the magnetic field. The morphology changes are discussed. No effect of the magnetic field on the crystallographic structure was observed.     

Chelate von Chinolin-8-ol-Derivaten. VI. Komplexbildung und Extraktion von Kupfer mit alkyl- bzw. alkenylsubstituierten Chinolin-8-olen

Chelates of 8-Quinolinol Derivatives. VI. Complex Formation and Extraction of Copper with Alkyl and Alkenyl Substituted 8-Quinolinols The copper chelates of a series of 7-substituted alkyl and alkenyl 8-quinolinols as well as 2-, 5-, and 7-methyl-8-quinolinols were synthesized and the chemical bonding was studied by EPR spectroscopy in chloroform and pyridine solution. Spectral changes in the chloroformic solutions of the chelates produced by pyridine are the result of a slow destruction reaction. For the extraction of copper in the chloroform/water system the extraction parameters as well as distribution data of the ligands were determined.     

Zinn(IV)-Komplexe mit dreizähnigen diaciden Liganden

Tin(IV) Complexes with Tridentate Diacidic Ligands By template reactions including bis(acetylacetonato)-dichloro-tin(IV) and O-aminophenol as well as o-aminothiophenol, benzoylhydrazine, and thiobenzoylhydrazine the tin chelates of tridentate diacidic ligands containing ligator atoms were prepared. To characterize the compound, IR, UV-VIS and Mössbauer spectroscopy were used. Crystal structure analyses demonstrate the existence of disturbed octahedral structures. Bis[acetylacetonbenzoylhydrazonato(2-)]tin(IV): space group P2₁/c, Z = 4, 2501 observed unique reflections, R = 0.045. Lattice dimensions at 20°C: a = 992.3, b = 2405.5, c = 1071.8pm, β = 116.94°. Bis[acetylacetonthiobenzoylhydrazonato(2-)] tin(IV): space group P2₁/c, Z = 4, 3603 observed unique reflections, R= 0.029. Lattice dimensions at 20°C: a = 1581.5, b = 947.8, c = 1644.9pm, β = 90.32°.     

Rate of copper extraction and structure of model β-diketones and 4-acyl-5-pyrazolones

The rate of copper extraction with individual 4-acyl-5-pyrazolones and the stability of various enolic and keto forms and their monohydrates were studied. The rate of extraction depends mainly upon the structure of substituent at position 4 and falls when the substituent becomes spacy. The effect of the substituent at position 1 is rather low. The enolic form with intramolecular hydrogen bonding is the most stable. It can form hydrates with water molecules without intramolecular hydrogen bond breaking.     

Komplexbildung und Extraktion von Molybdän(VI) mit zweizähnigen Liganden

Coordination and Extraction of Molybdenum(VI) with Bidentate Ligands A series of bidentate ligands as well as their thio derivatives from the groups of 8-quinolinols, β-diketones, acylpyrazolones, and N-acyl-phenylhydroxylamines was studied for the ability to extract molybdenum(VI) from heptamolybdate. The extraction principally runs only in acidic medium, sulfur-containing extractants having no advantage. The composition of the complexes was determined by the isolation of compounds in the solid state and also by the interpretation of distribution data.     

Struktur und ausgewählte Reaktionen von ReCl4(PPh3)2

ReCl₄(PPh₃)₂ – Reactions and Structure The compounds ReCl₄(PPh₃)₂ and Re₂OCl₃(C₂H₅COO)₂(PPh₃)₂ resulting from the reaction of ReOCl₃(PPh₃)₂ with PPh₃ in boiling propionic acid and HCl atmosphere were characterized by their VIS-spectra and structural data. Ligand exchange reactions with acetylacetone gave ReCl₂(acac)₂ as well as ReCl₂(acac)(PPh₃)₂. Crystallographic data see “Inhaltsübersicht”.