Absorptionsspektrographische Studien an l-Ascorbinsäure I

Ohne ZusammenfassungMit 9 Abbildungen.Vgl. hierzuE. Schauenstein, Chemie56, 156 (1943) bzw.R. Czmiel, W. Halden undE. Schauenstein, Naturwiss.30, 586 (1942). — Eine Zusammenfassung der vorliegenden Arbeit erschien bereits in dieser Zeitschrift [Mh. Chem.78, 415 (1948)] als vorläufige Mitteilung.     

δ-Santalolanaloga II Synthesen in der Isocamphanreihe, 28. Mitt.

The synthesis of 3-(3,3-dimethyl-2-exo-norbornyl)-2-methylprop-2-en-1-ol (3) and of 8-hydroxymethyl-8-methylcamphene (4) is described.3 and4 are analogues of -Santalol (1) with the allylic hydroxyl group in a position of two or three carbon atoms closer to the bicyclic nucleus compared to1. 4 is also an analogue to Patchenol® which is used sometimes to blend the patchouli oil. The odour impression of these compounds, of the pureendo-epimer of3, and of theendo-exo-mixture of3 are described and compared with the odour of1 and a further analogue whose synthesis has already been reported in a preceding paper [1].

Auszugsweise vorgetragen auf der gemeinsamen wissenschaftlichen Tagung der ÖPhG und DPhG am 11. September 1986 in Innsbruck. Die Synthese von4 wurde bereits am 15. März 1983 anläßlich des 9th International Congress of Essential Oils in Singapore vorgestellt.     

Photoelektronenspektroskopische untersuchung von tris(trimethylelement(IV)aminen, -phosphinen, -arsinen und -stibinen

The PE spectra of [(CH₃)₃Sn]₃N, [(CH₃)₃E]₃P (E = C, Si, Sn), [(CH₃)₃Si]₃As and [(CH₃)₃E]₃Sb (E = C, S, Ge, Sn) are analyzed. The constant level of the ionization potentials of the n-hybrid orbitals of N, P, As, and Sb, together with changes in the hybridization and interactions with ligand MO's is discussed by qualitative MO investigations.     

Über Reaktionen mit Betain, 24. Mitt.: Über Umsetzungen von Trimethylammoniumessigsäurebetain mit reaktiven Halogenverbindungen

Summary Diethyl bromomalonate and bromoacetonitrile, respectively, react with trimethylammonium acetic acid betaine in ethanol to give diethyl tartronate and glycolic acid nitrile, respectively. By analogy, ethyl -chloroacetonate and ethyl bromopyruvate yield the respective hydroxy derivatives which were identified by their osazones2 and3. Under the same experimental conditions, mesoxalic acid and its dimethyl ester, respectively, are formed from dibromo malonic acid and its dimethyl ester and were characterized by their known hydrazones8 and9.

Herrn o. Prof. Mag. pharm. Dr. H. Junek, Karl-Franzens-Universität Graz, zur Vollendung des 60. Lebensjahres mit besten Wünschen gewidmet     

M(mu-CN)Fe(mu-CN)M' chains with phthalocyanine iron centers: redox, spin-state, and mixed-valence properties

Dinuclear complexes with M-CN-ZnPc and M-CN-FePc-CN arrays and trinuclear complexes with M(mu-CN)Fe(mu-CN)M' arrays containing central metal phthalocyaninato (Pc) and external Cp(dppe)Fe or Cp(PPh3)2Ru building blocks (M) and having all possible orientations of the bridging cyanide ligands were subjected to electrochemical and preparative redox reactions. The species with unpaired electrons show characteristic MMCT bands in the near-IR spectra, the energies of which depend in a typical fashion on the nature of the building blocks and the orientation of the cyanide bridges and can be correlated with the redox potentials. Cyclic voltammetry has revealed electronic communication between the external organometallic units. An analysis of the MMCT spectra allows the assignment of the odd-electron complexes as class II mixed-valence species. The magnetic moments of the complexes with central Fe(III)Pc units are characteristically higher than the spin-only value for one unpaired electron. A M?ssbauer investigation has shown that the M-CN-Fe(III)Pc-NC-M complexes undergo a low-spin-to-high-spin crossover of the Fe(III) component above room temperature.     

Identification of levoglucosan and related steroisomers in fog water as a biomass combustion tracer by ESI-MS/MS

A conspicuous fraction of the water soluble organic compounds (WSOC) in fog and fine aerosol samples is composed by monosaccharide anhydrides, such as levoglucosan and its stereoisomers, galactosan and mannosan. Levoglucosan is produced exclusively during wood combustion processes, making it a very useful tracer for plant combustion emissions in the atmosphere. This paper describes a new experimental approach, based on electrospray-tandem mass spectrometry (ESI-MS/MS), for the identification of levoglucosan in fog water samples. The analytical method proposed allows to identify the specific sugar anhydrides directly in the liquid phase without the need of any derivatization process.     

Zur Stickstoff- und Sauerstoffbestimmung in Uranverbindungen nach dem Vakuumhei?extraktionsverfahren

Zusammenfassung Die Einsatzfähigkeit eines Routine-Hochvakuumheißextraktionsgerätes auf dem Gebiet der Analyse von Stickstoff und Sauerstoff in Uranverbindungen wird durch Vergleich mit anderen Methoden überprüft. Es zeigt sich, daß ein solches Gerät auf diesem Gebiet mit Erfolg eingesetzt werden kann. Sauerstoff und auch Stickstoff werden bei Anwendung von Graphitkapseln von 0,14 bzw. 0,3 cm³ Rauminhalt in Gegenwart von Reinst-Nickel als Badmetall bei 2000° C quantitativ extrahiert. Es werden genaue Arbeitsvorschriften für die Bestimmung von Stickstoff und Sauerstoff in UN, UCN und UC gegeben.

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Determination of nitrogen and oxygen in uranium compounds using the vacuum hot extraction method

The possibility of using a standard high-vacuum hot extraction equipment in the analysis of nitrogen and oxygen contained in uranium compounds was verified by comparison with other methods. The use of such an equipment in this field proved to be successful. Oxygen and nitrogen are extracted quantitatively at 2000° C in the presence of very pure nickel as the bath metal with the use of graphite capsules of 0.14 and 0.3 cm³ capacity, respectively. Precise instructions are given for the determination of nitrogen and oxygen in UN, UCN, and UC.

     

Beschleunigung schwerer Ionen im Sonnenwind

Ohne Zusammenfassung