Optical velocity measurements of electrolytic boundary layer flows influenced by magnetic fields

Magnetic fields are applied to electrically conducting fluids in order to influence electrochemical processes through the magnetohydrodynamic effect. Various phenomena, e.g. on electrodeposited metal layers, which can be attributed to forced convections were observed. To provide information about acting forces, the laser Doppler velocity profile sensor was applied to measure the transition layer of a Lorentz force influenced flow over a backward-facing step and the velocity boundary layer during copper deposition. With this sensor, the electrolyte convection within < 500 μm of the front of an electrode is measured with a spatial resolution down to 15 μm. The interaction of buoyancy, Lorentz and magnetic field gradient forces is studied by measuring the velocities down to 10 μm in front of the cathode. Inside the concentration boundary layer, complex electrolyte convection is induced, which varies not only in time but also in its structure, depending on the forces present and their influence over time. In inhomogeneous magnetic field configurations, the magnetic field gradient force dominates the velocity boundary layer at steady state and transports electrolyte toward regions of high magnetic gradients, where maximum deposit thicknesses are found. In this way, the measurements confirm the predicted influence of the magnetic field gradient force on the structuring of copper deposits.     

New hardware for radio frequency powered glow discharge spectroscopies and its capabilities for analytical applications

A new radio frequency (rf) hardware is developed for glow discharge spectroscopic methods. The resulting features and its capabilities for analytical applications are discussed. The electrical equipment developed allows to work as quickly, stably, reliably and easily as known from the direct current (dc) mode. Moreover, the rf power measurement has been improved. The hardware has been developed, optimised and tested for glow discharge optical emission spectroscopy (GDOES), but nevertheless it is possible to use it for all procedures applying glow discharge sources.     

Metallverbindungen Meso-alkylsubstituierter Thio-β-diketone

By Claisen type condensation of suitable ketones with dithiocarbonic esters meso-alkyl substituted thio-β-diketones were prepared and studied in their sensitivity towards metal ions. Real metal chelates could be obtained only with cobalt(III) and nickel(II). The compounds of lead(II), cadmium(II), zinc(II), copper(I), mercury(II), silver(I), palladium(II), platinum(II) and rhodium(III) show an unchelated carbonyl group in the IR spectrum and are therefore interpreted as mercaptides. From the IR spectra it is also concluded that the free ligands are predominantly existing in the enethiolic tautomeric form. The absence of visible absorption bands characteristic for usual thio-β-diketones and their metal chelates in the case of the meso-substituted derivates is discussed as a consequence of distortion of the molecule accompanied by a decrease of conjugation.     

Titan(IV)-Komplexe mit dreizähnigen diaciden Liganden. Kristallstruktur von Bis[2,6-diphenacylpyridinato(2 –)]titan(IV)

Titanium(IV) Complexes with Tridentate Diacidic Ligands. Crystal Structure of Bis[2,6-diphenacylpyridinato(2–)]titanium(IV) The titanium(IV) chelates with 2,2′-dihydroxy-azobenzene, salicylaldehyde-2-hydroxyanil, 2-(2′-hydroxyphenyl)-8-quinolinol, 2,6-diphenacylpyridine as well as with aroylhydrazones of salicylaldehyde, benzoylacetone and thenoyltrifluoroacetone were synthesized by ligand exchange reactions of titanium(IV)-isopropoxide. The compounds are red or black in colour and were identified by distinct molecular peaks in the mass spectra. The crystal and molecular structure was determined for bis[2,6-diphenacylpyridinato(2–)] titanium(IV). Crystallographic data see “Inhaltsübersicht”.     

Struktur von Bis[salicylaldehyd-2-hydroxyanilato(2—)]vanadium(IV)

Molecular Structure of Bis[salicylaldehyde-2-hydroxyanilato(2—)]vanadium(IV) By the reaction of tris(acetylacetonato)vanadium(III) with salicylaldehyde-2-hydroxyanil the non-oxo vanadium(IV) complex of this ligand was prepared. Bis[salicylaldehyde-2-hydroxyanilato(2—)]vanadium(IV) has a distorted octahedral structure. Crystallographic data see “Inhaltsübersicht”.     

Synthese und extraktionseigenschaften von 2-(sym-dibenzo-14-krone-4-oxy)essigsäure bzw. -n-hexansäure

(Synthesis and extraction behaviour of 2-(sym-dibenzo-14-crown-4-oxy)-acetic and -hexanoic acid)An improved synthesis for carboxylic acid derivatives of dibenzo-14-crown-4- using sodium amide is described. The reagents were studied for the extraction of alkali and alkaline earth metal ions. The dependence of the metal distribution on pH and ligand concentration is used to evaluate the composition of the extracted species. (2-sym-Dibenzo-14-crown-4-oxy)hexanoic acid is a very good extractant for alkaline earth metal ions but is also if interest for lithium.     

Chelate von β-Dicarbonylverbindungen und ihren Derivaten. XXIV. Stabilitätskonstanten von Metallchelaten unterschiedlich substituierter Pivaloylacylmethane

Chelates of β-dicarbonyl compounds and their derivatives. XXIV. Stability constants of metal chelates with differently substituted acylpivaloylmethanes Stoichiometric stability constants of copper(II), beryllium(II), nickel(II), cobalt(II) and zinc(II) chelates of 25 differently substituted acylpivaloylmethanes are determined in dioxane-water mixture and relations for calculating thermodynamic constants are given. The influence of aromatic and aliphatic substituents of the β-diketones on complex stability is discussed.     

Chelate von β-Dicarbonylverbindungen und ihren Derivaten. XXX. ESR-Untersuchungen an Kupferchelaten des Typs Cu [N2S2]

Chelates of β-Dicarbonyl Compounds and their Derivatives. XXX. EPR Studies on Copper Chelates of Cu[N₂S₂] Type Two copper(II) chelates with ligands containing sulphur and nitrogen in 1,3-positions were investigated by the EPR method. The Cu? S bond was found to be more covalent than the Cu? N bond.     

Chelate von β-Dicarbonylverbindungen und ihren Derivaten. 48 Ligandeigenschaften von 1-Phenyl-3-methyl-4-thiobenzoylpyrazolon, -4-benzoylthiopyrazolon und -4-benzoylselenopyrazolon

Chelates of β-Dicarbonyl Compounds and their Derivatives. 48. Properties of the 1-Phenyl-3-methyl-4-thiobenzoylpyrazolone, -4-benzoylthiopyrazolone, and -4-benzoylselenopyrazolone Ligands Thio and seleno derivatives of 1-phenyl-3-methyl-4-benzoyl-pyrazolone were synthesized by reaction of 1-phenyl-3-methyl-pyrazolon with dithiobenzoic ester and by reaction of the analogue 4-benzoyl-5-chlorpyrazole with sodium hydrosulfide or -selenide. Metal chelates of Cu, Ni, Co, Zn, Cd, Hg, Tl, and In were isolated. The influence of the central atoms on the optical behaviour was studied.