Vicarious nucleophilic substitution of hydrogen in nitro-1,6-methano[10]annulenes

Summary The 2- and 3-nitro-1,6-methano[10]annulenes and their 11,11-difluoro derivatives react with carbanions bearing leaving groups at the carbanionic center according to the Vicarious Nucleophilic Substitution of Hydrogen (VNS) scheme. The analogy between corresponding annulenes and naphthalenes with respect to reactivity is discussed.

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Vicarielle nucleophile Substitution von Wasserstoff in Nitro-1,6-methano[10]annulenen

Zusammenfassung 2- und 3-Nitro-1,6-methano[10]annulene und ihre 11,11-Difluoroderivate reagieren mit Carbanionen, die am carbanionischen Zentrum Abgangsgruppen aufweisen, nach dem Schema der vicariellen nucleophilen Substitution (VNS). Die Analogie zwischen entsprechenden Annulenen und Naphthalinen bezüglich ihrer Reaktivität wird diskutiert.

     

Einwirkung der natriumzitrate auf das berlinerblau

1. Prussian blue is soluble in the sodium citrates to form sodium ferrocyanide and sodium ferric citrate. It is much less soluble in disodium citrate than in trisodium citrate, and nearly insoluble in monosodium citrate. 2. Colloidal solutions are formed when the sodium citrates are added to Prussian blue in much smaller quantities than is required to produce a complete solution. 3. The peptizing action of the sodium citrates is explained by the formation of water soluble colloidal sodium ferric ferrocyanide NaFe[Fe(CN)₆]. 4. The peptizing action of the potassium oxalates and of the neutral alkali tartrates is also explained by the formation of KFe[Fe(CN)₆].     

Zur Kenntnis der 1-Methylisatine

Ohne ZusammenfassungDer Schmelzpunkt liegt um 145°. Das Krystallisationsvermögen ist ein geringes. Das mikroskopische Bild scheint auf monokline tafelförmige Krystalle zu deuten, welche zum Teil unvollkommen ausgebildet sind. Charakteristisch für die Substanz ist die grüne Fluoreszenz der alkoholischen Lösungen.Die Arbeit wird fortgesetzt.     

New reactions of nickel and cobalt with iron-cyanogen compounds and a new method of determination of ferricyan

Nickel ferrocyanide in presence of acids is oxidised by the oxygen of the air to nickel ferricyanide. Cobalt ferrocyanide is oxidised under the same conditions to a ultramarine blue substance with a slight grayish tinge. This substance is very similar to Prussian blue and to Turnbull's blue and could be called cobalt Prussian blue. This blue substance is also formed if mixtures of potassium ferrocyanide and potassium ferricyanide are precipitated with an excess of cobalt salt. This investigation led to the conclusion that the blue substance is probably not a mere mixture of cobalt ferrocyanide and cobalt ferricyanide. but the compound 6 Co₂[Fe(CN)₆]. Co₃[Fe(CN)₆]₂. A new method of the determination of ferricyan is described. Moreover, it was proved that some statements of former investigators on the reactions of nickel and cobalt with iron-cyanogen compounds are erroneous, and some iron-cyanogen compounds of nickel and cobalt described in the literature do not exist at all.