Die experimentelle Bestimmung der Neutronenstreulänge für das Wismutatom mit Hilfe der Totalreflexion an einem flüssigen Wismutspiegel

We construct generalized HF- and HB-equations fitted for building the symmetry properties of the Hamiltonian into. Therefore we use the method of Green's functions for condensed systems. The structure of HF- and HB-equations is conserved, only the density and pairing matrices change. Physical quantities may easily be calculated.     

Zur protonischen Leitfähigkeit von Eis-Einkristallen bei tiefen Temperaturen und hohen Feldstärken

In the course of an investigation of the electrical conductivity of ice single crystals a technique was developed for achieving electric fields of 450 kV/cm at low temperatures. Protons were injected into the sample from specially designed Pd electrodes. TheI – V (current-voltage) characteristics were found to resemble those due to space-charge limited currents which are well known inelectronic semiconductors. The concentration and depth of proton-traps, and the temperature dependence of the proton mobility were studied over a temperature range with a lower limit of 77°K. On the basis of these observations a number of mechanisms are proposed which contribute to the proton conductivity.     

Thermally driven acoustic oscillations,part III: Second-order heat flux

Summary The second-order heat flux in thermally driven oscillations of gas columns is calculated and given in a form suitable for numerical evaluation. Order-of-magnitude estimates are made in the case of steep temperature gradients.

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Zusammenfassung Der Wärmestrom zweiter Ordnung, der in thermisch getriebenen akustischen Schwingungen einer Gassäule entsteht, wurde berechnet und ist in einer für numerische Rechnungen geeigneten Form angegeben worden. Die Grössenordnung des Effektes wurde für steile Temperaturgradienten abgeschätzt.

     

Metal coordination to the formal P=N bond of an iminophosphorane and charge-density evidence against hypervalent phosphorus(V)

The iminophosphorane Ph(2)P(CH(2)Py)(NSiMe(3)) (1) was treated with deprotonating alkali metal reagents to give [(Et(2)O)Li[Ph(2)P(CHPy)(NSiMe(3))]] (2), [[Ph(2)P(CH(2)Py)(NSiMe(3))]Li[Ph(2)P(CHPy)(NSiMe(3))]] (3) and [[Ph(2)P(CH(2)Py)(NSiMe(3))]Na[Ph(2)P(CHPy)(NSiMe(3))]] (4). We report their coordination behaviour in solid-state structures and NMR spectroscopic features in solution. Furthermore, we furnish experimental evidence against hypervalency of the phosphorus atom in iminophosphoranes from experimental charge-density studies and subsequent topological analysis. The topological properties, correlated to the results from NMR spectroscopic investigations, illustrate that the formal P=N double bond is better written as a polar P(+)--N(-) single bond. Additionally, the effects of metal coordination on the bonding parameters of the iminophosphorane and the related anion are discussed.     

Selective synthesis of U-shaped terpyridines. Versatile ligands for the preparation of platinum complexes

The development of a simple and highly selective method for the preparation of substituted U-shaped terpyridines is described. The treatment of imine 5 with ternary iminium salts 2 leads to the terpyridines 4. A possible mechanism is discussed. The terpyridine derivatives are used for the preparation of several platinum(II) complexes 14. Complex 14e is characterized by single-crystal X-ray analysis.     

Structure and Dynamics of Molecular Rods in Membranes: Application of a Spin‐Labeled Rod

Molecular rods consisting of a hydrophobic backbone and terminally varying functional groups have been synthesized for applications for the functionalization of membranes. In the present study, we employ a spin‐labeled analogue of a recently described new class of molecular rods to characterize their dynamic interactions with membranes. By using the different approaches of ESR and NMR spectroscopy, we show that the spin moiety of the membrane‐embedded spin‐labeled rod is localized in the upper chain/glycerol region of membranes of different compositions. The rod is embedded within the membrane in a tilted orientation to adjust for the varying hydrophobic thicknesses of these bilayers. This orientation does not perturb the membrane structure. The water solubility of the rod is increased significantly in the presence of certain cyclodextrins. These cyclodextrins also allow the rods to be extracted from the membrane and incorporated into preformed membranes. The latter will improve the future applications of these rods in cellular systems as stable membrane‐associated anchors for the functionalization of membrane surfaces.     

Coordination preferences of the alkali cations sodium and caesium in the mixed‐cationic Zintl ammoniate Cs3.2Na0.8Ge9·5.3NH3

The involvement of two different alkali cations in the nonagermanide ammoniate Cs_3.2Na_0.8Ge₉·5.3NH₃ [tricaesium sodium nonagermanide–ammonia (1/5.3)] provides insights into the coordination behaviour of ammonia towards sodium and caesium cations within one compound and represents the first mixed‐cationic solvate structure of nonagermanide tetraanions. The compound crystallizes in the monoclinic space group P2₁/m and, with the presence of pseudomerohedral twinning, mixed‐cation sites and disordering of the nonagermanide cage anions, features a combination of crystallographic challenges which could all be resolved during the refinement.