Dipole excitations in 122Te, 126Te and 130Te

Excited states of the nuclei ¹²²Te, ¹²⁶Te and ¹³⁰Te were populated via the (γ, γ') reaction at endpoint energies of the bremsstrahlung between 4.5 and 5.5 MeV. Gamma rays were detected with a EUROBALL-CLUSTER detector and a single detector. In all nuclei several dipole transitions were identified at energies around 3 MeV. The lowest corresponding J = 1 states are interpreted as two-phonon excitations. Quasiparticle-phonon-model calculations predict one 1^? state arising from the coupling of the first quadrupole and the first octupole phonon and one 1⁺ state arising from the coupling of the first and the isovector second quadrupole phonon at about 3 MeV. The calculated transition strengths are compatible with experimental ones.     

Beiträge zur Chemie des Siliciums und des Germaniums. XXXVII. Weitere Untersuchungen zur Darstellung eines Silangemisches

Contributions to the Chemistry of Silicon and Germanium. XXXVII. Further Investigations to the Preparation of a Mixture of Silanes A production unit with 20 l reactor for preparation of greater amounts of silanes is described, which is a further developement of our earlier apparatus with 50 l reactor, and the cooling system of which also allows the condensation of disilane. The process is based on the method of acid decomposition of magnesium silicide used by STOCK . Furthermore we report about differences concerning reactivity and yield occuring with the decomposition of 21 kg melted and 17 kg sintered magnesium silicide of different grain size.     

Untersuchung von Kartoffeln, Gerste und Malz

Ohne Zusammenfassung     

Asymmetric Synthesis of Spirocyclic β‐Lactams through Copper‐Catalyzed Kinugasa/Michael Domino Reactions

The first copper‐catalyzed highly chemo‐, regio‐, diastereo‐, and enantioselective Kinugasa/Michael domino reaction for the desymmetrization of prochiral cyclohexadienones is described. In the presence of a chiral copper catalyst, alkyne‐tethered cyclohexadienones couple with nitrones to generate the chiral spirocyclic lactams with excellent stereoselectivity (up to 97 % ee, >20:1 dr). The new method provides direct access to versatile highly functionalized spirocyclic β‐lactams possessing four contiguous stereocenters, including one quaternary and one tetra‐substituted stereocenter.