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  • 2010-2014
  • 1980-1984  (487)
  • 1975-1979  (351)
  • Inorganic Chemistry  (596)
  • Physical Chemistry  (242)
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 14 (1982), S. 955-975 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Dark-phase experiments between isoprene and O3 are discussed. UNC outdoor chamber experiments have shown that in high-concentration systems of isoprene and O3 (5 ppm C and 1 ppm) approximately 75% of the reacted carbon can be observed in the product formation of HCHO, CO, methacrolein, methylvinylketone, methylglyoxal, acetaldehyde, and propylene. Mechanisms were developed which gave reasonable fits to dark-phase chamber experiments of MACR, MVK, isoprene, and O3. Experimental data and modeling results were used to generate O3 rates of attack on MVK and MACR. An isoprene-O3 rate of 1.67 × 10-2 ppm-1·min-1 was used and is consistent with other rates reported in the literature. Dark isoprene-O3 systems appear to form homogeneously nucleated aerosol. Most of these particles appear and remain at diameters well below the optical cutoff region (0.3-0.5 μm), as opposed to the particles from similar α-pinene-O3 systems, which also form at smaller sizes but then grow into the optical size range (0.5 μm). Lower concentrations of α-pinene and O3 (0.2 ppm C and 0.12 ppm) still generated substantial aerosol, but by comparison, rapid CN nucleation was not observed during a similar side-by-side system of isoprene and O3.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigations on the Catalysis of Ammonia Synthesis and Nitrogen Isotope Exchange by Lamellar Compounds of Graphite with Iron, Ruthenium, and OsmiumThe catalytic activity of transition metal potassium-graphite lamellar compounds for the synthesis of ammonia from the elements and the catalysis of the equilibration by isotope exchange of the isotopic nitrogen molecules are shown to correlate. Connections between the state of metal in the catalyst exist with iron as metal which is shown by Mössbauer spectroscopy and the catalytic activity in relation to the potassium content.
    Notes: Die katalytische Aktivität von Übergangsmetall-Kalium-Graphitverbindungen bei der Synthese von Ammoniak aus den Elementen und bei der Einstellung des Isotopenaustauschgleichgewichts der isotopen Stickstoffmolekeln korrelieren miteinander. Im Falle von Eisen als Metall sind Beziehungen zwischen dem durch Mößbauer-Spektroskopie ermittelten Zustand des Metalls im Katalysator und der katalytischen Aktivität in Abhängigkeit vom Kaliumgehalt erkennbar.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 466 (1980), S. 76-80 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Einfluß der Dehydratation von Calciumhydroxylapatit auf seine ZellparameterHydroxylapatit-Proben mit unterschiedlichem Ca/P-Verhältnissen wurden durch Festkörperreaktion dargestellt.Temperung bei unterschiedlichen Temperaturen bei einem PH2O von 5 mm Hg ergab unterschiedliche Dehydratationsgrade. Die Zellparameter a und c wurden mit hoher Genauigkeit bestimmt und scheinen mit dem OH-Gehalt zu sinken. Die Proben waren bei Raumtemperatur stabil, was die Theorie widerlegt, daß der kariessenkende Effekt des Fluorids auf der Diffusionshemmung im Hydroxylapatit beruht.
    Notes: Hydroxylapatite samples with different Ca/P ratio's were prepared by solid state reaction. Heating at different temperatures under PH2O = 5 mm Hg resulted in different degrees of dehydration. Cell parameters a and c were determined with a high accuracy and appeared to decrease with the OH content. The samples were stable in air at room temperature which disproves the theory that the caries reducing effect of fluoride would be due to the inhibition of diffusion in hydroxyapatite.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 415 (1975), S. 285-288 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Die Kristallstruktur von KaliumdithioacetatKaliumdithioacetat, KCH3CS2 wurde durch Reaktion von Dithioessigsäure mit K2CO3 in wäßriger Lösung dargestellt. Es kristallisiert orthorhombisch in der Raumgruppe Cmcm. Dimensionen der Elementarzelle: a = 7,689, b = 10,565, c = 6,490 Å, Z = 4. Koordinationszahl des Kaliums: 8. Die Strukturverfeinerung nach der Methode der kleinsten Quadrate ergab schließlich R = 0,097.
    Notes: Potassium dithioacetate KCH3CS2 was obtained by action of dithioacetic acid on potassium carbonate in aqueous solution. KCH3CS2 crystallizes orthorhombic within the space group Cmcm. The cell dimensions are: a = 7.689, b = 10.565, and c = 6.490 Å, Z = 4. The coordination number of potassium is 8. Structural refinement by least-squares method came to a final R = 0.097.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 514 (1984), S. 49-60 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Poly- and Spirocyclic Silylhydrazones  -  Synthesis and Molecular StructuresBulky aminotrifluorosilanes react with lithiated dimethylketone-hydrazone to give 1,2-diaza-3-sila-5-cyclopentenes  -  DSCP  -  (1, 2). The 4-silylated (3-5, 8-15) and siloxysilyl-substituted (17, 18) rings eliminate no halosilane or siloxane thermally. Lithiated 2 dimerises with LiF elimination to give the (2+2)cycloadduct of a 1,2-diaza-3-sila-3,5-cyclopentadiene (6). Lithiated DSCP reacts with MeSiF2N(CMe3)SiMe2CMe3 via a nucleophilic 1,3-methanide ion migration to form LiF and the spirocyclic compound 18. A compound with spirocyclic silicon (21) is formed in the reaction of bis(1,2-diaza-3-sila-5-cyclopenten-4-yl)difluorosilane (19) and the lithium salt of dimethyl-ketone-tert-butylhydrazone. The crystal structures of 6 and 21 are reported.
    Notes: Voluminöse Aminotrifluorsilane reagieren mit lithiiertem Dimethylketon-hydrazon zu 1,2-Diaza-3-sila-5-cyclopentenen  -  DSCP  -  (1, 2). In 4-Stellung silyl- (3-5, 8-15) und siloxysilylsubstituierte (17, 18) Ringe spalten thermisch kein Halogensilan oder Siloxan ab. Lithiiertes 2 dimerisiert unter LiF-Abspaltung zum (2+2)Cycloaddukt eines 1,2-Diaza-3-sila-3,5-cyclopentadiens (6). Lithiiertes DSCP reagiert mit MeSiF2N(CMe3)SiMe2CMe3 unter LiF-Ab-spaltung und nucleophiler 1,3-Methanidionen-Wanderung zum Spirocyclus 18. Eine Verbindung mit spirocyclischem Silicium (21) entsteht in der Reaktion des Bis-(1,2-diaza-3-sila-5-cyclopenten-4-yl)-difluorsilans (19) mit dem Lithiumsalz des Dimethylketon-tert-butyl-hydrazon. Die Kristallstrukturen von 6 und 21 werden mitgeteilt.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 116 (1983), S. 3877-3883 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Eine Fourier-Transform-Ionen-Cyclotron-Resonanz-Studie zur Struktur von Phenyl-substituierten 2-Azaallenium-IonenDurch Protonenabstraktionsreaktionen in Kombination mit Deuterium-Markierungsexperimenten wird gezeigt, daß die Ionen 1-3, die durch Elektronenstoß aus Benzylidenaminen durch Alkylradikal-Abspaltung aus der α-Position erzeugt werden, die Struktur von Phenyl-substituierten 2-Azaallenium-Ionen besitzen. Die durch die Deprotonierung entstehenden Moleküle zeigen sehr hohe Gasphasenbasizitäten (größer als 231.7 kcal/mol).
    Notes: It is shown by proton abstraction reactions in combination with deuterium labelling that the initial structure of the ions 1-3 generated by electron impact from some benzylideneamines through loss of an alkyl radical via α-cleavage is indeed that of phenyl-substituted 2-azaallenium ions. The deprotonated species appear to have very high gas-phase basicities, that are higher than 231.7 kcal/mol.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3880-3885 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesen von α,β-ungesättigten und anderen reaktiven AcylcyanidenReaktive aliphatische Acylcyanide (1-10, siehe Tab. 1) werden aus Acylchloriden, Natriumiodid und Kupfer(I)-cyanid unter verschiedenen Bedingungen dargestellt. Die Reaktion verläuft über die Acyliodide.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 1256-1258 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Eine neue Darstellung von Dehydrocamphenilon und CamphenilonBenzilsäureumlagerung von Dehydrocarbocamphenilon (4) ergibt die α-Hydroxysäure 5, welche mit Bleitetraacetat oxidativ zu Dehydrocamphenilon (2) decarboxyliert wird. Die gleiche Reaktionsfolge führt von Carbocamphenilon (9) zu Camphenilon (3).
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2626-2634 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Mass Spectrometric Investigation of Nitrogen Compounds, XXXV. Phenyl-substituted 2-Azaallenium Ions in the Gas PhaseThe gas phase chemistry of metastable phenyl-substituted 2-azaallenium ions (2a,b,c) is characterized by intramolecular electrophilic substitution reactions; these processes are energetically favoured in comparison with various phenyl and hydrogen migrations, in spite of the fact that the latter may give rise to the formation of more stable intermediates (nitrilium ions). As a direct consequence of the electrophilic substitution, 2a, c decompose via loss of HCN, whereas from 2b PhCN is eliminated unimolecularly. The combination of experimental investigations, employing [2H]-and [13C]-labelled precursors, and MNDO calculations allows to give a detailed description of the chemistry of isolated 2a,b,c cations.
    Notes: Für die Gasphasenchemie metastabiler phenylsubstituierter 2-Azaallenium-Ionen (2a,b,c) sind intramolekulare elektrophile Substitutionen charakteristisch; diese sind energetisch günstiger als diverse Phenyl- und Wasserstoff-Wanderungen, obwohl letztere zu thermochemisch stabileren Zwischenprodukten (Nitrilium-Ionen) führen. Als Folge der elektrophilen Substitution zerfallen 2a und 2c unimolekular unter HCN-Eliminierung, während aus 2b PhCN eliminiert wird. Experimente unter Benutzung [2H]- und [13C]-markierter Substrate liefern zusammen mit MNDO-Rechnungen ein detailliertes Bild für die Chemie von „isolierten“ 2a,b,c-Kationen.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    International Journal of Chemical Kinetics 9 (1977), S. 841-862 
    ISSN: 0538-8066
    Keywords: Chemistry ; Physical Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The oxidation of cerous ions by bromate ions in sulfuric acid medium was followed spectrophotometrically under various experimental conditions. The results were compared to the calculated predictions on the basis of a mechanism suggested by R. M. Noyes and collaborators. The computations were done by solving the complete set of the kinetic differential equations. The results of the computations show that the proposed mechanism explains adequately most of our and previous experimental data. In particular, the mechanism predicts the main features of the reaction, namely, the induction and the fast and slow reaction periods which occur during the oxidation.
    Additional Material: 16 Ill.
    Type of Medium: Electronic Resource
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