Mechanismus und Selektivität des Alkali-Ionentransportes in Modell-Membranen in Gegenwart des Antibioticums Valinomycin

Selective transport of potassium ions through synthetic membranes impregnated with valinomycin in octane-2-ol in the presence of equal amounts of K⁺ and Na⁺ or Li⁺ ions is induced on application of a potential difference across these membranes. By using ¹⁴C-labelled valinomycin it is shown that transport of potassium ions is accompanied by an equivalent transport of valinomycin within the membrane, consistent with the formation of a 1 : 1 complex of K⁺ with valinomycin. The exchange of ligands is shown to occur during the transport process so that a carrier-relay mechanism, as proposed earlier for macrotetrolide-mediated potassium transport, accounts for all experimental results on the bulk membranes studied.     

Untersuchung der Reaktivität und Sinterungsaktivität von Eisen(III)-oxid mittels der Diffusion radioaktiver Edelgase

Various methods for introduction of radioactive noble gases into solids are reviewed and also the diffusion of radioactive noble gases in α-iron(III)oxide, labelled by different methods. The HAHN emanation and ion bombardment methods have been used. Different noble gas diffusion processes have been shown to occur during heating the type of which is influenced by the kind of labelling conditions. The values of the activation energy of the noble gas diffusion are compared. Lattice defects including the amorphous state of Fe^IIIoxide are produced by ion bombardment. On the basis of the diffusion behaviour of radon, being studied by the emanation method, the “activity” of Fe^III oxide prepared by heating of different iron salts and sintered at various temperatures has been estimated. It is shown that the emanation method can be used for the study of the sintering of ferric oxide. On the basis of the solid state reaction ZnO + Fe₂O₃ the reactivity of ferric oxide in dependence on its thermal history has been investigated.     

Zum Mechanismus der Autoxydation von Vanadium (IV)-Komplexen

The stoichiometry and the kinetics of the autoxidation of vanadium(IV)-picolinic acid complexes are studied. Oxygen is reduced to H₂O₂, a stable peroxovanadate being formed as end product.     

Untersuchungen an Metallkatalysatoren. 37. Zum Einfluß der Beladung auf Aktivität und Selektivität von Nickel/Träger-Katalysatoren

Investigations on Metal Catalysts. 37. On the Influence of the Loading on Activity and Selectivity of Supported Nickel Catalysts Strong metal-support interactions effect a distinct decrease of the hydrogenolysis activity. They can be detected with diminishing metal loading in the following order: Ni/TiO₂ > Ni/Al₂O₃ > Ni/SiO₂. Strong metal-support interactions mean an influence on the electronic properties of the metal crystallites. On the other hand a mechanical mixture of nickel and η-Al₂O₃ is more active in hydrogenolysis than nickel.     

Magnetochemische und Mößbauerspektroskopische Untersuchungen an Eisen(II)-Komplexen mit Cyanmethanid- bzw. Cyanamidliganden

Magnetic and Mössbauer Measurements of Iron(II) Complexes with Cyanmethanide and Cyanamide Ligands Iron(II) complexes with cyanmethanide and cyanamide ligands were characterized using ⁵⁷Fe Mössbauer effect and magnetic measurements. The pseudo-octahedral complexes exist in a high spin d⁶ configuration and obey the Curie-Weiss-Law. The Weiss constants have been estimated graphically. The isomer shift δ, the quadrupole splitting ΔE and the magnetic moments are discussed in dependence of the complex structure proposed.