„Verstümmelte“ Grundeinheiten für biquadratische und bikubische Zahlkörper

Ohne Zusammenfassung     

Chemistry and biochemistry of branched-chain sugars

Branched-chain sugars have recently been isolated in larger numbers from microorganisms and higher plants as glycoside components of antibiotics or phenolic compounds. They also occur in plants in cell wall polysaccharides. Sugars with methyl, hydroxymethyl,formyl, hydroxyethyl, and glycoloyl branches have so far been found in nature. Many new methods have been developed for the synthesis of these sugars. With one exception, the branched sugars known at present can be divided biogenetically into three groups. Sugars with methyl branches are formed by C₁ transfer, sugars with hydroxyethyl branches by C₂ transfer to a hexose chain, and sugars with hydroxymethyl or formyl branches by rearrangement of a hexose or pentose chain.     

Pauli-correct separable potentials for composite particle interactions

Experimental totalβ-decay energies for short-lived isotopes of gallium and germanium are presented. The sources were produced as mass-separated fission products at the OSIRIS on-line separator at Studsvik. By applyingβ-γ-coincidence methodsQ _α-values were determined for^80,81Ga and^79,81,82Ge. For these nuclei on or close to the shellN =50 and in the vicinity of ther-process “seed”, the atomic mass excess is derived and compared with predictions from mass formulae.     

Oxide ultra-thin films on metals: new materials for the design of supported metal catalysts

Ultrathin oxide films on metals offer new opportunities for the design of supported nanoclusters with potential use in catalysis. This requires a characterization at the atomistic level of the structure and composition of the thin film, of its morphology and defect structure. A proper selection of metal/oxide interface, film thickness, lattice mismatch, etc. makes it possible to prepare collections of supported metal particles with novel properties. This critical review describes some illustrative examples, emphasizes the role of the interplay between theory and experiment, and relates some recent findings related to the possibility to control the charge state of a supported nanoparticle on an ultrathin oxide film (211 references).     

An accurate force field model for the strain energy analysis of the covalent organic framework COF-102

By using an accurate molecular mechanics force field, which was parametrized on the basis of first principles calculations, the network topology of the Covalent Organic Framework COF-102 could correctly be predicted without experimental input. The ctn structure is preferred thermodynamically by 11.2 kcal mol(-1) over the bor topology due to a lower steric strain. The origin for this strain is analyzed in detail.     

Rhodium(I) PNN Pincer Complexes with Proton-responsive Ligands: Synthesis,Characterisation, and Catalytic Dehydrocoupling of Amine Boranes

Coordination of a pyridine-pyrazole-based PNN(H) ligand to Rh^I produces a family of neutral ( 1 ) and cationic ( 2Cl ) Rh^I complexes. Deprotonation of the parent Rh chloride complex with LiNiPr₂ results in formation of a dinuclear LiCl bridged species 3 bearing a pyrazolate fragment. Complexes 1 , 2Cl and 3 were tested as precatalyst for the dehydrocoupling of amine boranes. All complexes studied show activity for the formation of cyclic oligomers with N-methylcyclotriborazane as the main product. Base activation of the neutral Rh chloride complex 1 produces catalyst systems that are significantly more active than the parent system, suggesting that dehydrohalogenation of the Rh chloride precatalyst 1 is one of the key steps for catalyst formation.