Ueber den Nachweis der Cyanverbindungen in forensen F?llen

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Zur Bestimmung des Reinheitsgrades von Kalium-, bezw. Natriumferrocyanid

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Alcuni elementi di meccanica negli spazi curvi

Sunto L'A. espone detti elementi col metodo della rappresentazione funzionale, metodo che, come egli dice, nella sostanza equivale al metodo vettoriale, ma nella forma lo supera per la scorrevolezza e per la naturalezza. L'A. approfitta della pubblicazione per sottolineare alcune osservazioni, delle quali pensa di dover trar partito in altra occasione.     

High-Pressure Synthesis of Metal–Inorganic Frameworks Hf4N20⋅N2, WN8⋅N2, and Os5N28⋅3 N2 with Polymeric Nitrogen Linkers

Polynitrides are intrinsically thermodynamically unstable at ambient conditions and require peculiar synthetic approaches. Now, a one-step synthesis of metal–inorganic frameworks Hf₄N₂₀⋅N₂, WN₈⋅N₂, and Os₅N₂₈⋅3 N₂ via direct reactions between elements in a diamond anvil cell at pressures exceeding 100 GPa is reported. The porous frameworks (Hf₄N₂₀, WN₈, and Os₅N₂₈) are built from transition-metal atoms linked either by polymeric polydiazenediyl (polyacetylene-like) nitrogen chains or through dinitrogen units. Triply bound dinitrogen molecules occupy channels of these frameworks. Owing to conjugated polydiazenediyl chains, these compounds exhibit metallic properties. The high-pressure reaction between Hf and N₂ also leads to a non-centrosymmetric polynitride Hf₂N₁₁ that features double-helix catena-poly[tetraz-1-ene-1,4-diyl] nitrogen chains [−N−N−N=N−]_∞.     

Hydrosilylation of Ketones,Imines and Nitriles Catalysed by Electrophilic Phosphonium Cations: Functional Group Selectivity and Mechanistic Considerations

The electrophilic phosphonium salt, [(C₆F₅)₃PF][B(C₆F₅)₄], catalyses the efficient hydrosilylation of ketones, imines and nitriles at room temperature. In the presence of this catalyst, adding one equivalent of hydrosilane to a nitrile yields a silylimine product, whereas adding a second equivalent produces the corresponding disilylamine. [(C₆F₅)₃PCl][B(C₆F₅)₄] and [(C₆F₅)₃PBr][B(C₆F₅)₄] are also synthesised and tested as catalysts. Competition experiments demonstrate that the reaction exhibits selectivity for the following functional groups in order of preference: ketone>nitrile>imine>olefin. Computational studies reveal the reaction mechanism to involve initial activation of the Si?H bond by its interaction with the phosphonium centre. The activated complex then acts cooperatively on the unsaturated substrate.