The nickel-catalysed carbonylation of 2-mercaptoethanol

2-Mercapthoethanol undergoes carbonylation in pyridine solution in the presence of oxygen and of [Ni(CO)₃Pyl as a catalyst to give cyclic O, S-ethylelnethiorcarbonate. The isolation of thiolatonickel compound [Ni(SCH₂CH₂OH)₂] by the oxidation of a solution containing [Ni(CO)₃Py] and 2-mercaptoethanol, and its reaction with carbon monoxide to give the cyclic thiocarbonate and [Ni(CO)₃Py] prove that the reaction proceeds in at least two steps.     

Synthesis, structures, and strain energies of dispirophosphiranes. Comparisons with dispirocyclopropanes

Six novel dispirophosphirane complexes have been synthesized from the reaction of bicycloalkylidenes with the electrophilic phosphinidene complex PhPW(CO)(5). They contain a central phosphirane ring, which is spirofused on one side to a cyclopropane or cyclobutane ring and on the other side with a three-, four-, five-, or six-membered ring. Their crystal structures and MP2/6-31G-computed geometries for simplified parent systems suggest that spirofusion with small rings results in a tightening of the central three-membered phosphaheterocycle, while spirofusion with larger rings results in a relaxation of the phosphirane geometry. Similar theoretical predictions are made for the corresponding annulated hydrocarbons. Strain energies for both the hydrocarbon and phosphorus series of structures have been calculated at G3(MP2). Whereas the [3]triangulane hydrocarbon and phospha[3]triangulane have a significant excess strain of 8.1 and 5.2 kcal/mol per spiroatom, respectively, the excess strain for systems spirofused with larger rings are negligible for the hydrocarbons and even negative for the phosphorus-containing species because of hyperconjugative stabilization.     

Dynamical and thermal aspects of relativistic heavy-ion collisions

Within a covariant BUU-approach we simulate heavyion collisions at various bombarding energies from 400 MeV/u to 1 GeV/u. We evaluate locally the energymomentum tensorT ^v (x), and extract pressures, energydensities and temperatures. The connection of these thermodynamical quantities to experimental observables and their sensitivity to the equation of state is discussed. Furthermore, we investigate the question of local equilibration and evaluate the entropy produced in these reactions.Dedicated to Prof. Dr. P. Kienle on the occasion of his 60th birthday. Work supported by BMFT and GSI Darmstadt     

Growth and characterization of Mn- and Co-doped ZnO nanowires

A flow injection chemiluminescence method is proposed for the determination of cobalt, based on the strong catalytic effect of Cobalt(II) (1,10-phenanthroline)₃ complex on the lucigenin-periodate reaction in alkaline medium. Under the optimum experimental conditions, the chemiluminescence signal responded linearly to the concentration of cobalt(II) in the 1.0 × 10⁻⁹–3.0 × 10⁻⁷ g mL⁻¹ range with a detection limit of 4.4 × 10⁻¹⁰ g mL⁻¹ cobalt(II). The relative standard deviation for the determination of 5.0 × 10⁻⁸ g mL⁻¹ of cobalt was 2.3% in eleven replicated measurements. The method was successfully applied to the determination of cobalt(II) in pharmaceutical preparations.     

Influence of surface structure on surface analytical statements

The influence of surface structure of technical materials on results and statements of surface analytical methods has been investigated. Especially surface roughness as a typical property of rolled products has been observed. For this purpose samples of steel (technical surface, roughness up to 5 m) and silicon wafers (polished surface) have been analyzed by SNMS and GDOS in order to get information about changes of the surface roughness as function of the sputtering time and their influence on the statements about the depth profiles obtained.