ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    A crossed laser-molecular beam study of the one and two photon dissociation dynamics of ferrocene at 193 and 248 nm (1989)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 90 (1989), S. 4248-4257 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: A crossed laser-molecular beam study of the one and two photon dissociation mechanism of bis (cyclopentadienyl) iron (ferrocene, FeCp2) has been performed at 193 and 248 nm. By combining electron bombardment mass spectroscopy with time-of-flight (TOF) measurements, the photodissociation mechanism at 193 nm is shown to have two distinct mechanisms. (1) FeCp2+hν→FeCp*+Cp; (2) FeCp+2hν→FeCp+Cp, FeCp→Fe+Cp. For the first mechanism, which accounts for less than 5% of the photodissociation events, the FeCp* velocity distribution is quantitatively consistent with a statistical dissociation producing FeCp in an excited, ligand field electronic state. The velocity distributions of the Cp and Fe fragments produced by the second mechanism (FeCp is an unstable intermediate) are also in excellent agreement with microcanonical calculations for both Cp elimination steps using the known metal–ligand bond energies of ferrocene. For the second mechanism, dissociation occurs on the lowest potential energy surface for each Cp elimination. Although one photon is energetically sufficient to remove one Cp ligand from ferrocene, RRKM calculations of the lifetime indicate that Cp elimination is extremely slow for dissociation along the ground electronic state potential energy surface. Hence, after internal conversion to the ground electronic state, the large photon absorption cross section (∼4 A(ring)2) for the experimental irradiation conditions allows additional photons to be absorbed until the dissociation rate exceeds the up pumping rate. The large photon energy causes the dissociation rate to increase by many orders of magnitude for each additional photon absorbed. Consequently, there is strong selectivity for the total number of photons absorbed. Both mechanisms, occurring on two different electronic potential energy surfaces, suggest that dissociation induced by excitation of the ligand-to-metal charge transfer states accessed at 193 nm can be quantitatively described as a statistical, unimolecular decomposition. At 248 nm, the measured product velocity distributions are qualitatively consistent with the mechanism deduced from the 193 nm results, but the energy available for translation at this wavelength is too small to extract quantitative producttranslational energy distributions which are required to independently test the applicability of the statistical dissociation model.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.455781
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    2'-Fluorinated arabinonucleosides of 5-(2-haloalkyl)uracil: synthesis and antiviral activity (1987)
    s.l. : American Chemical Society
    Journal of medicinal chemistry 30 (1987), S. 1199-1204 
    Details
    ISSN: 1520-4804
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1021/jm00390a013
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Still another proof of Parseval's equation for almost-even arithmetical functions (1988)
    Springer
    Aequationes mathematicae 35 (1988), S. 132-139 
    Details
    ISSN: 1420-8903
    Keywords: Primary 11K65 ; Secondary 11N37, 11A25, 43A60
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract Still another proof is given for Parseval's well-known equation $$\sum\limits_{1 \leqslant r〈 \infty } {|a_r |^2 \cdot \varphi (r) = \parallel f\parallel \begin{array}{*{20}c} 2 \\ 2 \\ \end{array} } $$ forB 2-almost-even arithmetical functionsf with Ramanujan coefficients $$a_r = \frac{1}{{\varphi (r)}} \cdot M(f \cdot c_r )$$ . An explicit “best approximation” off by even functions, constructed from characteristic functions of subsets {n; g.c.d.(n, r) =k} ⊂ $$\underset{\raise0.3em\hbox{$\smash{\scriptscriptstyle\cdot}$}}{\mathbb{N}} $$ is used.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01830940
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    High-level expression of Clostridium thermocellum cellulase genes in Escherichia coli (1987)
    Springer
    Applied microbiology and biotechnology 27 (1987), S. 50-56 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The Clostridium thermocellum cellulase genes celA and celC encoding endoglucanase A and C were subcloned in a temperature-regulated Escherichia coli expression vector containing the leftward promoterpl of bacteriophage lambda. The level of gene expression was controlled by thermal inactivation of the heat-sensitive lambda cI857 repressor. Under optimal conditions the recombinant endoglucanases A and C were expressed to a level of 10–15% of total cellular protein. Endoglucanase A was partially exported into the periplasmic space, whereas endoglucanase C was found sequestered within the cytoplasm. Overexpression of the celA gene resulted in decreased cell viability concomitant with the accumulation of endoglucanase A in the membrane fraction. In contrast, high-level synthesis of the celC gene product was well tolerated by the host cell. Overproduced endoglucanase C accumulated as a soluble enzyme without detectable formation of inactive inclusion bodies.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00257253
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    Degradation of barley β-glucan by endoglucanase C of Clostridium thermocellum (1988)
    Springer
    Applied microbiology and biotechnology 29 (1988), S. 25-31 
    Details
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary Endoglucanase C encoded by the celC gene of Clostridium thermocellum has been purified to homogeneity from a recombinant Escherichia coli strain. It was found that this enzyme is highly efficient in degrading glucans with alternating β-1,4- and β-1,3-linkages but lacks activity on unmodified cellulosic substrates. The properties of endoglucanase C were compared to those of Bacillus subtilis β-glucanase, an enzyme used in the brewing industry for β-glucan degradation. Both enzyme cause a rapid decrease of the viscosity of barley β-glucan as a result of internal chain cleavage. Endoglucanase C hydrolyses non-specifically β-1,3- and β-1,4-bonds adjacent to unsubstituted or 4-O′-substituted cellobiose units. Due to its lower pH optimum and increased thermostability endoglucanase C compares favourably with B. subtilis β-glucanase and seems suitable for use in the mashing process of beer brewing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00258346
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    5-Ethylthiomethyl- und 5-Ethylsulfonylmethylpyrimidine (1986)
    Springer
    Monatshefte für Chemie 117 (1986), S. 385-392 
    Details
    ISSN: 1434-4475
    Keywords: Halogen exchange, in pyrimidines ; Pyrimidines, 5-ethylsulfonyl-methyl- ; Pyrimidines ; 5-ethylthiomethyl-
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract In 2,4-dichloro-5-ethylthiomethylpyrimidines3a, b and in (2,4-dichloro-5-pyrimidinylmethyl)ethyl sulfones5a, b, resp., by reaction with ammonia, diethyl-amine, isopropylamine, sodium methanolate and sodium ethylthiolate, resp., the halogen atoms have been substituted by amino, methoxy or ethylthio groups, resp., and thus the compounds4a–4r and5c–5f have been obtained.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00816533
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Metallderivate von Molekülverbindungen. II. Darstellung und Struktur des β-Kaliumsilanids (1989)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 572 (1989), S. 75-88 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Derivatives of Molecular Compounds. II. Preparation and Structure of β-Potassium SilanideAt -5°C potassium silanide crystallizes from 1,2-dimethoxyethane/n-pentane in a to date unknown low temperature modification {β-form: orthorhombic, Pnma, Z = 4; a = 880.0(2), b = 541.6(1), c = 682.3(1) pm at -110 ± 3°C}. An x-ray structure determination shows the compound to be built up from isolated potassium cations and pyramidal silanide anions without perceptible disorder. Seven counterions make up the coordination sphere of either particle (K⃛Si 356 to 386 pm), two anion-anion contacts (Si⃛Si 355 pm) are observed in addition. The packing of ions represents a defect variant of the barite type, but there are also relationships to the high temperature modification (α-form, rock salt type) and to cesium trihydrogengermanide (thallium iodide type).
    Notes: Kaliumsilanid kristallisiert bei -5°C aus 1,2-Dimethoxyethan/n-Pentan in einer bisher unbekannten Tieftemperatur-Modifikation {β-Form: orthorhombisch, Pnma, Z = 4; a = 880,0(2), b = 541,6(1), c = 682,3(1) pm bei -110 ± 3°C}. Nach den Ergebnissen der Röntgenstrukturanalyse (R = 0,032) baut sich die Verbindung ohne erkennbare Fehlordnung aus isolierten Kalium-Kationen und pyramidalen Silanid-Anionen auf. Zur Koordinationssphäre beider Teilchen gehören sieben Gegenionen (K⃛Si 356 bis 386 pm); beim Anion kommen zwei zusätzliche Kontakte zu gleichnamigen Nachbarn (Si⃛Si 355 pm) hinzu. Die Kristallstruktur stellt eine Defektvariante des Baryt-Typs dar, Verwandtschaft besteht aber auch zur Hochtemperatur-Modifikation (α-Form, Steinsalz-Typ) und zum Caesium-trihydrogengermanidWährend der Name Kaliumsilanid unseres Erachtens eindeutig ist, sollte die homologe Germanium-Verbindung zur Unterscheidung von den binären Phasen Caesium-trihydrogengermanid genannt werden. (Thalliumiodid-Typ).
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19895720109
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Hydrogenolyse kleiner Kohlenstoffringe, XV über die Hydrierung von Dispiro[2.2.2.2]deca-4,9-dien (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 435-438 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: On hydrogenation of the title compound 1 with Pd/C 1,4-diethylbenzene (2) is formed in 95% yield, furthermore 1% of cis- and 2% of trans-1,4-diethylcyclohexane (3 und 4) as well as 2% of 6-ethylspiro[2.5]octane (15) are found. With Pt/C the intermediates 7, 12, 13, and 14 and up to 45% of dispiro[2.2.2.2]decane (17) are identified. 17 is hydrogenated with PtO2 in acetic acid to form 1,1,4,4-tetramethylcyclohexane (19).
    Notes: Bei der Hydrierung der Titelverbindung 1 mit Pd/C entsteht zu 95% 1,4-Diethylbenzol (2), daneben noch ca. 1% cis- und 2% trans-1,4-Diethylcyclohexan (3 und 4) sowie 2% 6-Ethylspiro-[2.5]octan (15). Mit Pt/C wird zusätzlich (bis zu 45%) Dispiro[2.2.2.2]decan (17) gebildet, und man erkennt die Zwischenstufen 7, 12, 13 und 14. Mit PtO2 in Eisessig wird 17 weiter zu 1,1,4,4-Tetramethylcyclohexan (19) hydriert.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871200330
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Amidinokomplexe von Molybdän(V) und Rhenium(V) Die Kristallstruktur von [Cl4Mo{i-Prop-NC(Cl) N-i-Prop}] (1985)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 522 (1985), S. 83-91 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Amidinocomplexes of Molybdenum (V) and Rhenium (V). Crystal Structure of [Cl4Mo{i-Prop-NC(Cl) N-i-Prop}]Molybdenum pentachloride and rhenium pentachloride, respectively, react with di-isopropylcarbodiimide in CCl4-suspensions forming the monomeric amidino complexes [Cl4M{i-prop-NC(Cl)N-i-prop}] (M = Mo, Re). According to the i.r. spectra the C—Cl-amidino ligand is bonded as a chelate. The molybdenum complex is characterized by an X-ray structure determination. It crystallizes in the tetragonalic space group I41/a with 8 formula units in the unit cell (1538 independent, observed reflexions, R = 0.051) with the lattice constants a = 1119 and b = 2332 pm.
    Notes: Molybdänpentachlorid bzw. Rheniumpentachlorid reagieren mit Di-isopropylcarbodiimid in CCl4-Suspensionen unter Bildung der monomeren Amidinokomplexe [Cl4M{i-Prop-NC(Cl)N-i-Prop}] (M = Mo, Re). nach den IR-Spektren ist der C-Chlor-amidinoligand als Chelat gebunden. Der Molybdänkomplex wurde durch eine röntgenorgraphische Strukturanalyse charakterisiert. Er kristallisiert in der tetragonalen Raumgruppe 141/a mit 8 Formeleinheiten pro Elementarzelle (1538 unabhängige, beobachtete Reflexe, R = 5,1%) mit den Gitterabmessungen a = 1119 und b = 2332 pm.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19855220310
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    Die Kristallstruktur von [Cl4P{i-Prop-NC(Cl)N-i-Prop}] (1985)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 525 (1985), S. 143-149 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Crystal Structure of [Cl4P{i-Prop-NC(Cl)N-i-Prop}]The monomeric di-isopropylcarbodiimide complex [Cl4P{i-Prop-NC(Cl)N-i-Prop}] crystallizes in the monoclinic space group C2 with 4 formula units in the unit cell and with the lattice constants a = 1391.2(2), b = 708.6(1), c = 1463.5(2) pm and β = 95.76(1)°. The structure was refined to an R-value of 0.026 (2084 independent, observed reflexions). Main parts of the IR and Raman spectrum of the compound are discussed.
    Notes: Der monomere Di-isopropylcarbodiimidkomplex [Cl4P{i-Prop-NC(Cl)N-i-Prop}] kristallisiert in der monoklinen Raumgruppe C2 mit 4 Formeleinheiten pro Einheitszelle und den Gitterkonstanten a = 1391,2(2), b = 708,6(1), c = 1463,5(2) pm und β = 95,76(1)°. Die Struktur wurde bis zu einem R-Wert von 0,026 verfeinert (2 084 unabhängige, beobachtete Reflexe). Wichtige Abschnitte des IR- und Ramanspektrums der Verbindung werden diskutiert.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19855250616
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...