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  • Chemistry  (56)
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  • 1
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Selenium Compounds. LXV. On Compounds of the Type (CH3O)3 SeX with X = F, Cl, Br, NO3, AlCl4Reaction of Se(OCH3)4 with SeX4(X = Cl, Br)(mole ratio 3:1) yields (CH3O)3SeX. The compounds (CH3O)3SeX (X = F, NO3) are formed by reaction of (CH3O)3SeCl with the silver salts AgF and AgNo3, respectively. (CH3O)3SeAlcl4 is prepared by reaction of (CH3O)3SeCl with AlCl3. Some properties of the synthezised compounds and the ir spectra are given. From their data deduction concerning the nature of the chemical bonds in the compounds (CH3O)3SeX are possible.
    Notes: Die Verbindungen (CH3O)3SeX mit X = Cl und br bilden sich durch Umsetzung von Se(OCH3)4 mit SeX4(Molverhältnis 3:1). Die verbindungen (CH3O)3SeF und (Ch3O)3SeNO3 entstehen bei der Reaction des Chlorids (CH3O)3SeCl mit AgF bzw. AgNO3. Das (Ch3O)3SeCl reagiert mit AlCl3 zu (CH3O)3SeAlCl4. Einige Eigenschaften der Verbindungen und die IR-Spektren werden mitgeteilt. Die IR-Spektren gestatten Aussagen zur Natur der Bindungsverhältnisse in den (CH3O)3 SeX-Verbindungen.
    Additional Material: 2 Tab.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 401 (1973), S. 179-184 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Selenium Compounds. LXVII. Preparation of Amides of the Selenious AcidBy reaction of [(CH3)2N]2SeO or (RO)2SeO with NH3, CH3NH2 and H2N—(CH2)2—NH2 the amides of the selenious acid (NH2)2SeO, (CH3NH)2SeO, and (CH2NH)2SeO are formed which are stable only at low temperatures. The thermic stability of the amides increases in the given order.
    Notes: Durch die Umsetzung von [(CH3)2N]2SeO bzw. (RO)2 SeO mit NH3, CH3NH2 und H2N—(CH2)2—NH2 entstehen die Amide der selenigen Säure (NH2)2SeO, (CH3NH)2SeO und (CH2NH)2SeO, die nur bei tiefen Temperaturen beständig sind. Die thermische Stabilität der Amide nimmt in der angegebenen Reihenfolge zu.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 404 (1974), S. 213-218 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on Selenium Compounds. LXIX. On the Reactivity of Diphenyl Selenium Dihalides with Ammonia, Alkyl- and SilylaminesThe halides Ph2SeX2 (Ph = C6H5; X = Cl, Br) are reduced by NH3, MeNH2 and Me2NH (Me = CH3) at -60°C forming Ph2Se. The reaction of Ph2SeCl2 with Me3SiNMe2 yields Ph2Se(NMe2)Cl, whereas with (Me3Si)2NH the salt [Ph2Se=N=SePh2]Cl is formed. The infrared spectra are presented and discussed.
    Notes: Die Halogenide Ph2SeX2 (Ph = C6H5; X = Cl, Br) werden durch NH3, MeNH2 und Me2NH (Me = CH3) auch bei -60°C zum Ph2Se reduziert. Bei der Umsetzung von Ph2SeCl2 mit Me3SiNMe2 entsteht Ph2Se(NMe2)Cl, während sich mit (Me3Si)2 NH das Salz [Ph2Se = N = SePh2]Cl bildet. Die IR-Spektren werden mitgeteilt und im Hinblick auf die Bindungsverhältnisse diskutiert.
    Additional Material: 2 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 321 (1979), S. 978-986 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Spektroskopie und Photochemie indigoider Verbindungen. VI. Direkte trans → cis Photoisomerisierung indigoider FarbstoffeWir haben die Fluoreszenz und die photochemische trans → cis Isomerisierung einiger indigoider Farbstoffe in flüssigen Lösungen bei 300 K und festen Gläsern bei 77 K, die Temperaturabhängigkeit der Fluoreszenzquantenausbeute und die Löschung der trans → cis Isomerisierung durch Elektronendonatoren in Benzen und Iodbenzen und durch O2 in Benzen untersucht. Diese und andere Ergebnisse werden vorgestellt und diskutiert. Es wird angenommen, daß die direkte trans → cis Photoisomerisierung  -  zumindest im ersten Schritt  -  über einen Singulett-Zustand verläuft.
    Additional Material: 6 Ill.
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  • 5
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The Photochromism of Fulgides. IX. Investigations of the Photochemistry of α-3,5-Dimethoxyphenyl-δ,δ-dimethylfulgideThe mechanism of photoisomerization of α-3,5-dimethoxyphenyl-δ, δ-dimethylfulgide was investigated by means of u.v./vis- and fluorescence spectroscopy. The quantum yields of E-Z isomerization and cyclisation were determined in various solvents and at different temperatures. Triplet sensitization of E-Z isomerization by several sensitizers has been found. The thermal dark reactions of the deep coloured species were reinvestigated.
    Additional Material: 9 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 222-232 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Carbon-13 Nuclear Magnetic Resonance Spectra of PhenylfulgidesThe carbon-13 chemical shifts are determined in a series of phenylfulgides in order to investigate steric and electronic influences of substituents. By means of the shift differences between suitably substituted compounds results can be obtained as to the relative variation of the rotation angles of the phenyl rings as well as to te angle alterations between the exocyclic double bonds and the anhydride ring. Introducing 4-CH3O- and 4-NO2-groups at the phenyl rings the substituent induced alterations of the carbon-13 chemical shifts and the π-polarization effects related with it are discussed.
    Additional Material: 3 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 233-247 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Electronic and Steric Substituent Influences on the U.V./VIS-Absorption Spectra of Phenylfulgide IsomersThe u.v./vis spectral data of a large number of phenylfulgides (E-, Z-, E-E-, E-Z-, Z-E-, Z-Z-isomers, 1.8a-dihydronaphthalenes) are presented. An increase of the number of phenyl rings as well as substitution of the phenyl rings cause correlatable bathochromic spectral shifts. Steric influences became obvious by introducing methyl groups, by coplanarization of phenyl groups and in the series of isomers. By means of PPP calculations shifts in position and/or intensity of absorption bands are ascribed to the substituent effects.The calculated band polarization of E(E-E)-isomers are in agreement with the results of polarization spectra in oriented liquid crystal mesophases. The polarization spectra allow the assignment of the longwave absorption band to the S2 ← S0 and S1 ← S0 electronic transitions for E-E-Isomers with a C2v-symmetry.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 705-720 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Direct and Sensitized Photoisomerization of α,δ-PhenylfulgidesThe photoreactions starting from the E- and E-E-isomers of mono-, di-, tri- and tetra-(substituted-)phenylfulgides are investigated. The phenylfulgides show strong steric interactions in the molecular framework. For that reason internal conversion is the main deactivation process which increases in the series of mono-, tri- and tetraphenylfulgides. The α,δ-di-(substituted-)-phenylfulgides show the highest photoreactivity. At room temperature in no case luminescence is observed from any E(E-E)-, Z(E-Z, Z-E)- or Z-Z-phenylfulgid isomer of the substances under study. Intersystem crossing cannot compete neither with thermal deactivation nor can it be observed by applying both the internal and external heavy atom effect. The phenylfulgides show typical ππ*-photoreactivity: in the singlet state E-Z-isomerization about one double bond competes with electrocyclic ring closure; in the triplet state only simultaneous E-Z-isomerization about the two double bonds is observed. The steric and electronic substituent influences on the photoreactivity are interpreted. A first qualitative model of the isomerization reactions of the fulgides in the excited states is established.
    Additional Material: 6 Ill.
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  • 9
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 326 (1984), S. 899-909 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Photooxidation of Leuco Dyes. VIII. Time Resolved Investigations of the Mechanism of the Photooxidation of Leucocrystal VioletThe photooxidation of leucocrystal violet has been reexamined by means of conventional and laser flash photolysis as well as spin trap experiments. Three radical transients have been observed and assigned to the cation radical (λmax ≈ 490, 530 nm), the neutral radical with one—NCH3—CH2 moiety (λmax ≈ 480 nm) and the triphenyl methyl radical derivative (λmax ≈ 400 nm).
    Additional Material: 10 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 303 (1960), S. 79-84 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: RAMAN and IR-spectra of (CH3O)2SeO, (C2H5O)2SeO, and CH3O · SeO · OC2H5 are given and discussed. Because of the fact that couplings between the CH-oscillations within the alkyl groups and between CH-oscillations and that of the C—O—-Se-sceletons are allowed to be neglected, it is possible to discuss the spectra.
    Notes: Es werden die RAMAN- und IR-Spektren von Dimethylselenit, Diäthylselenit und Methyläthyselenit mitgeteilt und diskutiert. Kopplungen zwischen den Alkylschwingungen der einzelnen Molekeln einerseits und zwischen den Alkylschwingungen und denen der COSe-Gerüste andererseits sind vernachlässigbar klein. Dadurch ist die Zuordnung der Gerüstfrequenzen möglich.
    Additional Material: 3 Ill.
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