Tetrajodterephtalsäure-derivate als Röntgen-Kontrastmittel

New monoamides and diamides of tetraiodoterephthalic acid have been synthesized for evaluation as X-ray contrast agents. Solubility, toxicity, bilitropism, urotropism, and in some cases cholecystographic quality of these compounds are given.     

Optisch aktive übergangsmetall-komplexe XX. Optisch aktive cyclopentadienyl-perfluoropropyl-kobalt-komplexe mit zweizähnigen schiff-basen

In the reaction of C₅H₅ Co(C₃F₇)(CO)I with the Schiff base NN′, derived from S-(-)-?-phenylethylamine and pyridine carbaldehyde-2, the salt [C₅H₅Co(C₃F₇)NN′]⁺ I^? (Ia,b) is formed, which can be transformed to [C₅H₅ Co(C₃F₇)NN′]⁺ PF₆^? (IIa,b). The sodium salt Na⁺ [NN″]^? of the Schiff base, derived from S-(-)-α-phenylethylamine and pyrrol carbaldehyde-2, in the reaction with C₅H₅ C0(C₃F₇)(CO)I yields the neutral complex C₅H₅ Co(C₃F₇)NN″ (IIIa,b). The diastereoisomeric pairs IIa,b and IIIa,b are separated by fractional crystallisation and chromatography respectively into the optically pure components which differ in their ¹H NMR spectra. The IR, UV, CD, mass spectra and optical rotations of the new compounds IIa, IIb, IIIa and IIIb are compared.     

Synthesen in der Naphthalinreihe: Methoxylierte Tetralone und Naphthole

Ohne ZusammenfassungHerrn Prof. Dr.A. Franke in aufrichtiger Verehrung zum 80. Geburtstag gewidmet.     

Ab initio SCF Calculation of the Fluoronium Ion: Geometry,electronic structure and vibrational constants

An ab initio SCF calculation of 42 points of the energy hypersurface of the fluoronium ion is presented using a contracted F(5s/3p), H(2s) gaussian basis set. In its equilibrium structure a bond length of 1.812 a.u. and a HFH bond angle of 127.2° are predicted. The calculated vibrational frequencies for H₂F⁺, HDF⁺, and D₂F⁺ are in good agreement with the experimental data.     

Optisch aktive übergangsmetall-komplexe : XXXIX. Stereospezifische phenyl-addition an das C5H5(CO)2 Mo-Pyridin-Carbaldimin-Kation

The addition of C₆H₅^? to the NN' ligand (NN' = Schiff base of pyridine carbaldehyde-(2) and (S)-(—)-α-phenylethylamine) in [C₅H₅ Mo(CO)₂ NN'] PF₆ occurs stereospecific from the side opposite to the C₅H₅-ring.     

Optisch aktive übergangsmetall-komplexe LXIV. Neue optisch aktive Cp(CO)Fe-acyl-komplexe mit

The novel complexes CpFe(CO)(COR)P(C₆H₅)₂NR'R^* with Cp = C₅H₅,C₉H₇ (indenyl); R = CH₃, C₂H₅, CH(CH₃)₂, CH₂C₆H₅;R` = H, CH<sub>3</sub>, C<sub>2</sub>H<sub>5</sub>, CH<sub>2</sub>C<sub>6</sub>H<sub>5</sub> and R<sup>*</sup> = (S)-CH(CH<sub>3</sub>)(C<sub>6</sub>H<sub>5</sub>), have been synthesized by reaction of CpFe(CO)<sub>2</sub>R wiht P(C<sub>6</sub>H<sub>5</sub>)<sub>2</sub>NR`R^* and characterized analytically as well as spectroscopically. The pairs of diastereoisomers RS/SS have been separated by preparative liquid chromatography and fractional crystallization, respectively. The optically pure complexes (+)₄₃₆- und ()₄₃₆-CpFe(CO)(COR)P(C₆H₅)₂NR`R^* are configurationally stable at room temperature. At higher temperatures they equilibrate with CpFe(CO)₂R and epimerize with respect to the Fe configuration.     

High- and low-confinement modes in simple magnetized toroidal plasmas

Three-field simulations of interchange turbulence are presented for a simple magnetized toroidal plasma with a vertical magnetic field. The simulations show the presence of two turbulent regimes characterized by low (L) and high (H) confinement properties. We evaluate analytically the properties of the L regime, obtaining expressions for the plasma gradients and for the density and heat fluxes that agree well with the simulations. By increasing the plasma source strength or reducing the vertical magnetic field, a transition to a H regime occurs, in which a strong velocity shear limits the perpendicular transport with respect to the L scaling and the plasma profiles steepen. The analytic estimate of the transition condition is in accord with the simulations.