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  • Wiley-Blackwell  (5)
  • 1995-1999  (2)
  • 1985-1989  (3)
  • 1920-1924
  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Liebigs Annalen 1995 (1995), S. 481-486 
    ISSN: 0947-3440
    Keywords: Dyes, fluorescent ; Perylene derivatives ; Heterocyclic rings ; Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Perylene-3,4:9,10-tetracarboxylic acid 3,4-anhydride-9,10-imides are condensed with primary diamines to a number of new basic chromophores with amidine-imide structures. Lightfast dyes are obtained which exhibit a strong fluorescence in solution. The absorption and fluorescence spectra of the title compounds are bathochromically shifted compared to those of the perylene dyes.
    Additional Material: 2 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: Studies on the Mechanism of the Antimony Pentachloride Intercalation in GraphiteThe SbCl5 intercalation in graphite in liquid media (immersion in SbCl5 and in SbCl5/CCl4-mixtures, respectively) reveals an induction period ranging from 0,25 up to 8 hours. Graphite intercalation by liquid SbCl4F, SbCl2F3 and SbF5 does not exhibit any induction period. The induction time of synthetic graphites is shorter than that of natural graphites. The decrease of graphite particle sizes as well as the increase of SbCl5 concentration in CCl4 solution and the presence of co-reagents (e.g. SbCl3) reduce the induction time. Increasing the SbCl5 concentration in CCl4, an increase of SbCl5 quantity in graphite and of identity period along c-axis in stage 2 have been found. Gase phase intercalation of SbCl5 is a reaction of successive lowering of the stage index without any induction period. Using EPMA investigations it have been stated that nucleation at the prismatic edges (opening of galleries) controls the intercalation kinetics. An explanation of induction period and „autocatalytic“ reaction after the induction period is given on basis of interaction of electrostatic forces, connected with adsorption of guest molecules, and elastic forces, resulting from dilatation during intercalation. Formation of complexes between SbCl5 and co-reagents (e. g. SbCl3) strengthens the electrostatic effect.
    Notes: Die Graphitintercalation von SbCl5 weist in flüssiger Phase (Immersion in SbCl5 bzw. in SbCl5/CCl4) eine Induktionsperiode von 0,25 bis 8 Stunden auf. Die flüssigen Verbindungen SbCl4F, SbCl2F3 und SbF5 intercalieren jedoch ohne Induktionsperiode. Die Induktionszeit hängt ab von Partikelgröße und Perfektionsgrad des Graphites, von der SbCl5-Konzentration im CCl4 und von der Gegenwart von Koreagenzien. Die Gasphasenintercalation von SbCl5 stellt eine Reaktion ohne Induktionsperiode mit sukzessiver Stufenerniedrigung dar. Aufgrund von ESMA-Untersuchungen muß die Keimbildung (Schichtöffnung) als reaktionskontrollierender Schritt angesehen werden. Eine Erklärung für die Induktionsperiode und anschließende “autokatalytische” Reaktion wird auf der Basis von Wechselwirkungen zwischen elektrostatischen und mechanischelastischen Kräften bei der Intercalation gegeben. Komplexe zwischen SbCl5 und Koreagenzien (z. B. SbCl3) erhöhen die elektrostatische Wechselwirkung.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Simultaneous Intercalation of Antimony Pentachloride with Metal Trichlorides into GraphiteThe metal trichlorides AsCl3, SbCl3, BiCl3, AlCl3, GaCl3, and FeCl3 intercalate simultaneously with SbCl5 into the graphite lattice forming intercalation compounds of a SbCl5: MCl3 ratio between 1:0.16 and 1:4.5. C24SbCl5(AsCl3)0.9 as well as C60SbCl5(GaCl3)4·5 are already formed by a spontaneous intercalation at 25°C. During co-intercalation of SbCl5 with BiCl3 and AlCl3, respectively, the ratios SbCl5:MCl3 decrease with increasing intercalation time. X-ray and EPMA measurements suggest that homogeneous mixtures of SbCl5 and trichlorides are inserted in the interlayer galleries. The identity periods along c-axis of the stage 1 and stage 2 compounds are Ic = 9.30 - 9.39 Å and Ic = 12.58 - 12.76 Å, respectively. In stage 1 SbCl5/AsCl3-graphite as well as SbCl5/GaCl3-graphite a simultaneous desintercalation of SbCl5 and MCl3 have been found in vacuum and by solvents. The successive stage increase during thermal deintercalation was investigated by thermogravimetric methods. Mass spectroscopic gas analysis of the pyrolysis products show that the thermal dissociation of SbCl5 superimposes stage transformations.
    Notes: Die Metallchloride AsCl3, SbCl3, BiCl3, AlCl3, GaCl3 und FeCl3 werden gemeinsam mit SbCl5 in das Graphitgitter eingelagert, wobei Intercalationsverbindungen mit einem Verhältnis SbCl5:MCl3 zwischen 1:0,16 bis 1:4,5 gebildet werden. Spontane Intercalation liefern bei 25°C die Verbindungen C24SbCl5(AsCl3)0,9 und C60SbCl5(GaCl3)4,5. Bei den Kointercalanten BiCl3 und AlCl3 nimmt das Verhältnis SbCl5:MCl3 in den Intercalationsverbindungen mit zunehmender Intercalationsdauer ab. Röntgenographische und ESMA-Befunde sprechen dafür, daß in den Schichtzwischenräumen Mischungen aus SbCl5 und den Trichloriden vorliegen. Die Identitätsperioden entlang der c-Achse betragen bei den Verbindungen der Stufe n = 1 Ic = 9,30 - 9,39 Å und der Stufe n = 2 Ic = 12,58 - 12,76 Å. Im Vakuum und durch Lösungsmittel werden SbCl5 simultan mit AsCl3 bzw. GaCl3 aus SbCl5/AsCl3-Graphit bzw. SbCl5/GaCl3-Graphit der Stufe n = 1 partiell desintercaliert. Mittels Thermogravimetrie wird die thermische Desintercalation aller Verbindungen untersucht.Massenspektroskopische Analyse der gasförmigen Desintercalationsprodukte beweist, daß die thermische Dissoziation des SbCl5 den Phasentransformationen mit sukzessiver Erhöhung der Stufenzahl n überlagert ist.
    Additional Material: 3 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 533 (1986), S. 37-48 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Gas Phase Intercalation of Graphite by SbCl4FGas Phase Intercalation of Graphite by SbCl4F using a two-zone technique is a method to prepare intercalation compounds of different stage index n in temperature range between 120 and 140°C. The reaction is a process of successive decrease of stage index. Increasing the reaction time, i. e. concentration, regions of pure stages alternate with two-phase regions. Intercalation compounds were characterized by X-ray technique, EPMA, and chemical methods. The compounds are stable in ordinary air, with aqueous HCl as well as KOH only pentavalent but not any trivalent antimony can be removed. The identity periods along c-axis in pure stages are Ic = 9.33 Å (n = 1), 12.72 Å (n = 2), 16.06 Å (n = 3) and 19.40 Å (n = 4). A (√7 × √ 7) 19.1° in-plane structure of intercalants was found. The uptake curve of mass with time reveals a discontinuity connected with formation of stage 2. Concave shape of curve during starting period at 120 and 125°C will be interpreted as a consequence of an induction time. From X-ray and EPMA studies it may be concluded that nucleation at the prismatic crystal edges controls the kinetics of reaction. Assuming a first order kinetics of filling the vacant sites, the same activation energy in case of formation of stage 1 and stage 2 have been determined approximately (97 and 102 kJ/mol).
    Notes: Durch Intercalation mit dampfförmigem SbCl4F sind Graphitintercalationsverbindungen mit unterschiedlichem Stufenindex n zugänglich. Die Gasphasenreaktion stellt eine sukzessive Erniedrigung des Stufenindex n dar, wobei einphasige Bereiche „reiner“ Stufen und zweiphasige Bereiche durchlaufen werden. Die Verbindungen sind an Luft relativ stabil; durch Extrahieren mit wäßriger HCl bzw. KOH läßt sich nur fünfwertiges Sb nachweisen. Die röntgenographische Charakterisierung lieferte für die Stufe n = 1 eine Identitätsperiode Ic = 9,33 Å, für n = 2 Ic = 12,72 Å, für n = 3 Ic = 16,06 Å und für n = 4 Ic = 19,40 Å. Für die Intercalantschichten wurde eine (√7 × √7) 19,1° in-plane-Struktur nachgewiesen. Kinetische Verfolgung des Umsatzes zeigt eine Diskontinuität bei der Stufe 2. Der Konkave Kurvenverlauf bei niedrigem Umsatz wird mit einer Induktionszeit interpretiert. Aus röntgenographischen und ESMA Befunden kann gefolgert werden, daß die Keimbildung an den prismatischen Kristallrändern den reaktionskontrollierenden Schritt darstellt. Auswertung nach einer Reaktion 1. Ordnung liefert für die Bildung der Stufen 1 und 2 nahezu die gleiche Aktivierungsenergie (97 und 102 kJ/mol).
    Additional Material: 6 Ill.
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  • 5
    ISSN: 0018-019X
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A novel general synthesis of 2,4,5-tri- and 2,4,5,6-tetrasubstituted pyrimidines 5a-d and 7a, e, f, g by condensation of thiouronium salts of type 3 with (ethoxymethylidene)malononitrile (4) and [bis(methylthio)methylidene]malononitrile (6), respectively, was first established in solution (Scheme 1) and successfully transferred onto solid support by using the polymer-bound thiouronium salt 11 (Scheme 3). Further investigations were directed toward a multidirectional cleavage procedure of the 2-(alkylsulfinyl) intermediates, obtained from the 2-(alkylthio)pyrimidines 7a (Scheme 2) or 12 and 14 (Schemes 3 and 4), with different nucleophiles to form highly substituted pyrimidines. In addition, fused-heterocycle derivatives 22a--h, 24a-c, and 26a-e were generated in good-to-excellent yields by condensation of 7a, e, h with versatile isocyanates and isothiocyanates, with subsequent alkylation (Scheme 5).
    Additional Material: 6 Tab.
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