Synthesis und Reaktivität von Dimethylaminoalkylidenaminooxy-arsinen

Synthesis and Reactivity of Dimethylaminoalkylideneaminooxiarsines The reactions of As[N(CH₃)₂]₃ with oximes result in the formation of the oximates [(CH₃)₂N]₂AsONCRR′, (CH₃)₂N As(ONCRR′)₂ and As(ONCRR′)₃. The eleavage of the As-N-bond with alcohols, thiols and diols are described. The reactions of CH₃As[N(CH₃)₂]ONCRR′ with water, amine and alcohols are examined. IR-and ¹H-NMR-spectral data are presented.     

Zur Reaktivität isomerer Heterodinuclearer Fischer-Carben-Komplexe mit Titanaoxetan- und Titanaoxolenteilstrukturen — Cycloreversions- und Insertionsreaktionen

Studies on the Reactivity of Isomeric Heterodinuclear Fischer-Carbene Complexes exhibiting a Titanaoxetan or Titanaoxolen Substructure – Cycloreversion and Insertion Reactions The reactivity of isomeric four- and five-membered carbene complexes Cp*₂ 3 and Cp*₂ 4 [ML_n: Cr(CO)₅ ( a ); W(CO)₅ ( b ); Cp*: C₅(CH₃)₅] has been investigated. A cycloreversion reaction, unusual for common metallaoxetanes, is found to dominate the chemical behaviour of 3 . The generation of vinylidene fragment [Cp*₂Ti?C?CH₂] 2 as an intermediate is proved either by trapping with ethylene and isocyanate or by protonation of the α-carbon atom. On the other hand no cycloreversion is observed for the titanaoxolene carbene complexes 4 . Ringenlargement is found by the reaction of 3 and 4 with isonitriles under formation of iminoacyl complexes. Accordingly 2,6-dimethylphenylisonitrile reacts with 3 b forming Cp*₂ 12 [Ar: 2,6-(CH₃)₂? C₆H₃]. A reversible insertion of cyclohexylisonitrile in 4a leads to isolation of the six-membered metallacycle Cp*₂ 16 (Cy: C₆H₁₁).     

Reaktivitäut und reaktionswege von methylsubstituierten bisindolylcarbenium-ionen

Methyl substituted bisindolylcarbenium ions 1 react with some O- and C-nucleophiles regioselectively. The cations 1b, 1c yield with hydroxide ions the tetraindolyldimethyl ether 4 and with methoxide ions the bisin-dolylmethoxymethanes 5. Compounds 1a, 1b, 1c react with several methylindoles to isomeric bis- and trisin-dolylmethanes. An electrophilic reactivity order of cations 1 can be derived supporting on the experimental results.     

Vergleichende Untersuchung zur Bestimmung von Phosphor und Bor in Halbleitersilicium

Zusammenfassung Die aus Hall-Effekt-Messungen an Siliciumeinkristallen ermittelten Verunreinigungsgehalte an Phosphor und Bor werden im Konzentrationsbereich zwischen 10^–5 und 10^–7 Gew.-% mit chemisch-analytischen Daten verglichen. Phosphor wird aktivierungsanalytisch, Bor spektrophotometrisch bestimmt. Unter Beachtung der Fehlergrenze jeder Methode findet man im allgemeinen befriedigende Übereinstimmung. Eine systematische Abweichung zwischen den Ergebnissen der elektrischen und der radiochemischen Phosphorbestimmung ist hauptsächlich auf einen Restgehalt von Chlor zurückzuführen, der bei der Aktivierungsanalyse stört.

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Summary The amounts of contaminant phosphorus and boron determined in silicon crystals by means of the Hall effect are compared in the concentration range between 10^–5 and 10^–7 weight-% with the chemical-analytical data. Phosphorus is determined by activation analytical methods, boron spectrophotometrically. Taking account of the limits of error of each method, satisfactory agreements are obtained in general. A systematic deviation between the electrical and the radiochemical phosphorus determination may be attributed primarily to a residual content of chlorine which interferes in the activation analysis.

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Résumé On compare les teneurs en phosphore et en bore à l'état d'impuretés dans les cristaux de silicium, dans le domaine de concentration allant de 10^–5 à 10^–7% en poids, déterminées à partir de l'effet Hall avec celles indiquées par les données chimico-analytiques. On dose le phosphore par analyse par activation et le bore par spectrophotométrie. En tenant compte des limites d'erreurs de chaque méthode, on trouve en général une concordance satisfaisante. Un écart systématique entre les résultats de dosage du phosphore électrique et radiochimique doit être attribué essentiellement à une teneur résiduelle en chlore, qui gêne dans l'analyse par activation.

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Dem Zentralinstitut für Kernphysik Rossendoff bei Dresden danken wir für die Bestrahlnng der Proben im Reaktor. Herrn Dr.S. Niese vom gleichen Institut sei besonders ffir die vorzeitige Mittei]ung seiner Untersuchungsergebnisse gedankt.     

Untersuchung der Reaktivität und Sinterungsaktivität von Eisen(III)-oxid mittels der Diffusion radioaktiver Edelgase

Various methods for introduction of radioactive noble gases into solids are reviewed and also the diffusion of radioactive noble gases in α-iron(III)oxide, labelled by different methods. The HAHN emanation and ion bombardment methods have been used. Different noble gas diffusion processes have been shown to occur during heating the type of which is influenced by the kind of labelling conditions. The values of the activation energy of the noble gas diffusion are compared. Lattice defects including the amorphous state of Fe^IIIoxide are produced by ion bombardment. On the basis of the diffusion behaviour of radon, being studied by the emanation method, the “activity” of Fe^III oxide prepared by heating of different iron salts and sintered at various temperatures has been estimated. It is shown that the emanation method can be used for the study of the sintering of ferric oxide. On the basis of the solid state reaction ZnO + Fe₂O₃ the reactivity of ferric oxide in dependence on its thermal history has been investigated.     

Untersuchung von CuGaSe2 und CuGaTe2 unter hohem Druck

Investigation of CuGaSe₂ and CuGaTe₂ under High Pressure The X-ray powder diffraction analysis at 300 K in dependence on the pressure gives a transition from the chalcopyrite-type to the NaCl structure for CuGaSe₂ at 12.5 GPa and for CuGaTe₂ at 8 GPa. The phase transition is associated with a discontinuity of the volume of 8.6 and 3.8%. These results were discussed in relation to other tetrahedrally coordinated compounds.