Neutraler Ionophor für Flüssigmembranelektroden mit hoher Selektivität für Natrium- gegenüber Kalium-Ionen

Neutral Ionophore for Liquid Membrane Electrodes of High Selectivity for Sodium Over Potassium Ions. The preparation of a neutral ion carrier suitable as a component for liquid membrane electrodes is described. These sensors may be used for the potentiometric determination of sodium ion activities with a discrimination of potassium ions by a factor of up to 250.     

Einfluss der Lipophilie von 3, 6-Dioxakorksäurediamiden auf ihr Verhalten als Ionophore

Influence of the lipophilicity of 3,6-dioxaoctanedioic diamides on their ion carrier properties A series of lipophilic 3,6-dioxaoctanedioic diamides (potential ionophores for Ca²⁺) have been prepared. With increasing lipophilicity the ionophoric behavior of these ligands vanishes. This loss is shown to be due to kinetic limitations in the exchange reactions between aqueous phase and membrane phase.     

Amin-Borane als Precursoren für Borcarbidnitrid

Amine-Boranes as Precursors for Boron Carbonitride Amine-Boranes have been investigated with respect to their thermal decomposition in the temperature range from rom temperature to 1050°C. The phase transformation of the pyrolytic residue derived from BH₃ · C₅H₅N subsequently heat-treated at temperatures up to 2200°C was studied. The progress of the pyrolysis has been detected by thermal analysis (TGA) and mass spectroscopy. Chemical analysis and ESCA measurements show that the pyrolytic products are single-phase boron carbonitride (B_xC_yN_z) which can be described as a boron and nitrogen containing pyrolytic carbon. This is also supported by means of analytical electron microscopy. Hot pressing of the pyridine-borane-derived B_xC_yN_z at 1800°C and a pressure of 190 MPa yields whiskerlike crystals whose d-values are in accordance with that of BN and/or graphite.