Modular and Selective Arylation of Aryl Germanes (C−GeEt3) over C−Bpin,C−SiR3 and Halogens Enabled by Light‐Activated Gold Catalysis

Selective C –C couplings are powerful strategies for the rapid and programmable construction of bi‐ or multiaryls. To this end, the next frontier of synthetic modularity will likely arise from harnessing the coupling space that is orthogonal to the powerful Pd‐catalyzed coupling regime. This report details the realization of this concept and presents the fully selective arylation of aryl germanes (which are inert under Pd⁰/Pd^II catalysis) in the presence of the valuable functionalities C?BPin, C?SiMe₃, C?I, C?Br, C?Cl, which in turn offer versatile opportunities for diversification. The protocol makes use of visible light activation combined with gold catalysis, which facilitates the selective coupling of C?Ge with aryl diazonium salts. Contrary to previous light‐/gold‐catalyzed couplings of Ar–N₂⁺, which were specialized in Ar–N₂⁺ scope, we present conditions to efficiently couple electron‐rich, electron‐poor, heterocyclic and sterically hindered aryl diazonium salts. Our computational data suggest that while electron‐poor Ar–N₂⁺ salts are readily activated by gold under blue‐light irradiation, there is a competing dissociative deactivation pathway for excited electron‐rich Ar–N₂⁺, which requires an alternative photo‐redox approach to enable productive couplings.     

In situ Mössbauer study of iron containing MFI ferrisilicates: Relations to catalytic properties

Ferrisilicates of MFI structure (HZSM-5) with Si/Fe ratios of 27.5, 35 and 67 have been studied by in situ Mössbauer spectroscopy, and the results are correlated with studies on catalytic conversions of toluene. Various species of iron ions are identified from 300 K spectra recorded after combinations of evacuation and reduction at 570 and 670 K, respectively. The roles of identified species are suggested in catalytic processes.     

Ueber eine einfache Gruppe von 504 Operationen

Ohne Zusammenfassung     

Ueber die Bestimmung des Stickstoffs in organischen Substanzen

Ohne Zusammenfassung     

Zur gruppentheoretischen Grundlegung der automorphen Functionen

Ohne Zusammenfassung     

Mehl, Teig, Backware

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Ueber ausgezeichnete Untergruppen in der Gruppe der elliptischen Modulfunctionen

Ohne ZusammenfassungVerallgemeinerung von Abschnitt I und II meiner Arbeit über die ausgezeichneten Gruppen des Geschlechtes Eins. Math. Ann. Bd. XXX, pag. S45.     

Ueber die ausgezeichneten Untergruppen vom Geschlechtep=1, welche in der Gruppe der linearen ω-Substitutionen enthalten sind

Ohne Zusammenfassung