Synthese und reaktivität von dienylmetall-verbindungen: XXI. Cyclopentadienylnickel-komplexemit sterisch anspruchsvollen phosphan-liganden

Bulky phosphanes PR₃ (R = C₆H₁₁, iC₃H₇, t-C₄H₉, C₆H₄CH₃-o) stabilize complexes of type [C₅H₅Ni(PR₃)L]BF₄ (L=S(CH₃)₂, (CH₃)₃PS), from which [C₅H₅Ni(PR₃)₂]⁺ cations are obtained. Iodide replaces the sulfur ligands to yield neutral C₅H₅Ni(PR₃)I compounds. No stable [C₅H₅Ni(PR₃)]⁺ cations could be obtained by iodide abstraction, but [C₅H₅Ni(PR₃)CO]⁺ cations were formed in the presence of carbon monoxide.     

Synthesen und Ringerweiterungsreaktionen von 2-(4-Hydroxyalkyl)-2-nitrocycloalkanonen

Syntheses and Ring-Enlargement Reactions of 2-(4-Hydroxyalkyl)-2-nitrocycloalkanones Syntheses of the title compounds were achieved by [Pd{P(C₆H₅)₃}₄]-catalyzed reaction of 2-nitrocycloalkanones 3 with vinyloxirane followed by catalytic hydrogenation. By another route, the known methyl 4-(1-nitro-2-oxocycloalkyl)butanoates 6 were reduced to the corresponding aldehydes 7 which by NaBH₄ reduction or methylation with (CH₃)₂Ti(i-Pr)₂ were transformed to the alcohols 5 and 8 , respectively (Saheme 1). Treatment of 5 and/or 8 with KH/THF under reflux gave, via a 7-membered intermediate, the nitrolactones 12 and oxolactones 13 (Scheme 3). Compared with similar reactions running via 5- or 6-membered intermediates (see 1 and 2 ), the yields are distinctly lower. The natural occurring 12-tridecanolid ( 14 ) was synthesized.     

Erzeugung von sieben- und sechsring-alkinen durch photolyse und thermolyse von cyclopropenonen

A six-membered and two seven-membered cycloalkynes, namely 1 – 3, are generated by matrix photolyses of the corresponding cyclopropenones 4 – 6 at about 15 K and characterized by spectroscopic means and in two cases by identification of the trimerization products 9 and 10.     

Nachweis von Ferro- und Ferricyanid durch Katalyse

Zusammenfassung Es wird ein Nachweis von Ferro- und Ferricyanid mit Wasserstoffsuperoxyd und Paraphenetidin beschrieben, der darauf beruht, daß die an sich langsam verlaufende Oxydation des Paraphenetidins durch Wasserstoffsuperoxyd durch Ferricyanid (bzw. durch Ferrocyanid + Wasserstoffsuperoxyd) katalysiert wird. Empfindlichkeit und Grenzverhältnisse dieser Farbreaktion wurden bestimmt.

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Summary A test for ferricyanide by means of hydrogen peroxide and para phenetidine is described. It is based on the fact that oxydation of para phenetidine by hydrogen peroxide, being slow in itself, is catalized by ferricyanide (or ferrocyanide + hydrogen peroxide). Sensitivity and limits of proportion of this colour reaction are determined.

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Résumé L'auteur décrit le décèlement du cyanure ferreux et du cyanure ferrique avec le peroxyde d'hydrogène et la paraphénétidine. L'oxydation de la paraphénétidine par le peroxyde d'hydrogène qui, de coutume, ne se fait que lentement, est catalysée par le cyanure ferrique (cyanure ferreux + peroxyde d'hydrogène). La sensibilité de cette réaction colorante fut déterminée.

     

Trennung von Indium und Cadmium durch Papierchromatographie

Ohne Zusammenfassung     

Die Trennung von RaD. RaE und RaF durch Ionenaustausch

Ohne Zusammenfassung     

Probenvorbereitung von Ferrolegierungen und Sintern durch Umschmelzen und Feinstmahlung

For the sample preparation of many ferroalloys in connection with their analysis by optical emission or X-ray spectrometry the recasting process has been approved. In those cases in which due to high viscosity of the melt, reactions with the refractory material of the crucible or the influence of oxygen the recasting technique is not applicable, the samples can be prepared by “wet grinding”. The following example shows the typical conditions: 60 g of a ferroalloy and 60 ml isopropanol are grinded for 5 min in a disk swing mill. The final step of preparation is done by pressing of the material received. Furthermore, oxide materials may be prepared by wet grinding. The described wet grinding process completes the other wellknown preparation techniques like remelting and chemical decomposition.     

Trennung von In und Zn durch Ionenaustausch

Ohne Zusammenfassung     

Benzolactone und Benzocarbocyclen durch Ringerweiterung von Benzocycloalkenonen

Benzolactones and Benzocarbocycles by Ring Enlargement of Benzocycloalkenone Derivatives The Michael adducts 5–8 of benzonitrocycloalkenones 1–4 and acrylaldehyde are converted with (CH₃)₂ Ti(iPrO)₂ or NaCNBH₃ to secondary and primary alcohols, 9–12 and 13–16 , respectively. These alcohols react under basic conditions to form ring-enlarged benzonitrolactones and benzooxolactones (Scheme 1). The configuration of the bicyclic intermediates in this enlargement step is discussed. The Michael reactions of benzonitrocycloalkenones with methyl vinyl ketone lead to oxoalkyl-benzonitrocycloalkenones 35--38 . These products rearrange in the presence of t-BuOK to yield benzonitrocycloalkenones 42 , 44 , and 46 , enlarged by two C-atoms, or tricyclic hydroxy compounds 39 , 41 , 43 , and 45 (Scheme 4).     

Trennung von Eisen und Zirkonium durch Aminextraktion

Ohne ZusammenfassungDem Herrn Bundesminister für Atomkernenergie und Wasserwirtschaft danken wir für finanzielle Unterstützung.