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  • 1
    Electronic Resource
    Electronic Resource
    Über Aromatenkomplexe von Metallen, CXVCXIV. Mitteil.: E. O. Fischer und R. J. J. Schneider, Chem. Ber. 103, 3684 (1970) (1972)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 105 (1972), S. 3014-3026 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Aromatic Complexes of Metals, CXVCXIV. Mitteil.: E. O. Fischer und R. J. J. Schneider, Chem. Ber. 103, 3684 (1970). Über Di-π-cyclopentadienyl-μ-π-cyclopentadien-dimetall-Komplexe des Palladiums, Nickels und Platins, „Tetracyclopentadienyl-dipalladium“ und π-Cyclopentadienyl-π-(2-methyl-1-acetyl-allyl)-palladium. On Di-π-cyclopentadienyl-μ-π-cyclopentadienedimetal Complexes of Palladium, Nickel, and Platinum as well as on „Tetracyclopentadienyldipalladium“ and π-Cyclopentadienyl-π-(2-methyl-1-acetylallyl)palladiumMetal halides MX2 = PdBr2, NiI2 yield with alkali cyclopentadienides and cyclopentadiene a new diamagnetic type of compounds according to An analogously composed platinum complex was detected too. Spectroscopic investigations support a molecular structure with a metal-metal bond, two π-bonded C5H5-rings and a π-bonded C5H6-ring as bridge in a manner that the compounds can be described as di-π-cyclopentadienyl-μ-π-cyclopentadienedimetal complexes. - Variation of the reaction conditions led to Pd2C20H20 mixed with Pd2(C5H5)2C5H6. Pd2C20H20 was proved by mass spectroscopy and so the question of a „tetracyclopentadienyldipalladium“ is settled. It should, however, exist as di-π-cyclopentadienyl-μ-π-(5-cyclopentadienylcyclopentadiene)dipalladium. According to violet, diamagnetic π-cyclopentadienyl-π-(2-methyl-1-acetylallyl)palladium was obtained.
    Notes: Metallhalogenide MX2 = PdBr2, NiJ2 ergeben mit Alkalicyclopentadieniden und Cyclopentadien einen neuen diamagnetischen Verbindungstyp nach Ein analog zusammengesetzter Platin-Komplex konnte ebenfalls nachgewiesen werden. Spektroskopische Untersuchungen sprechen für einen Molekülaufbau mit Metall-Metall-Bindung, zwei π-gebundenen C5H5-Ringen und π-gebundenem C5H6 als Brücke, so daß die Verbindungen als Di-π-cyclopentadienyl-μ-π-cyclopentadien-dimetall-Komplexe aufzufassen sind. - Durch Änderung der Reaktionsbedingungen im Gemisch mit Pd2(C5H5)2C5H6 entstehendes Pd2C20H20 ließ sich massenspektroskopisch sichern und damit die Frage nach einem „Tetracyclopentadienyl-dipalladium“ beantworten, das jedoch als Di-π-cyclopentadienyl-μ-π-(5-cyclopentadienyl-cyclopentadien)-dipalladium vorliegen dürfte. - Nach entsteht violettes, diamagnetisches π-Cyclopentadienyl-π-(2-methyl-l-acetyl-allyl)-palladium.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19721050923
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  • 2
    Electronic Resource
    Electronic Resource
    Ueber Amido- und Oxyphenanthrenchinon (1885)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 18 (1885), S. 1942-1944 
    Details
    ISSN: 0365-9496
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.18850180227
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  • 3
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    Myocardial perfusion quantification using the T1-based FAIR-ASL method: The influence of heart anatomy, cardiopulmonary blood flow and look–locker readout (2013)
    Wiley-Blackwell
    Details
    Publication Date: 2013-07-10
    Description: Purpose The quantification of myocardial perfusion using a Look–Locker flow-sensitive alternating inversion recovery- arterial spin labeling experiment is considered. Due to the anatomy of the heart, a substantial but unintended partial inversion of the inflowing blood occurs during the slice-selective inversion. Both, the partial inversion as well as the Look–Locker pulse train, influence the myocardial perfusion quantification and are addressed in this work. Methods The mean relaxation time approximation is used to calculate the monoexponential relaxation time of the signal in perfused tissue under Look–Locker readout. The left ventricular blood serves as an approximation of the inflowing blood in the description of FAIR-ASL measurements with global and slice-selective inversion to correctly quantify the myocardial perfusion. Results The analysis shows that the myocardial perfusion can be overestimated if the T 1 -based quantification method is not adapted respecting the Look–Locker pulse train explicitly. Additionally, it turns out that without correction for the partial inversion of the blood pool during the slice-selective inversion the myocardial perfusion is underestimated. Conclusion It is shown that the Look–Locker readout as well as the nonideal slice-selective inversion experiment have a considerable influence and have to be included properly to correctly quantify myocardial perfusion. Magn Reson Med, 2013. © 2013 Wiley Periodicals, Inc.
    Print ISSN: 0740-3194
    Electronic ISSN: 1522-2594
    Topics: Medicine
    Published by Wiley-Blackwell
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  • 4
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    CAMAM: A Miniature Laser Ablation Ionisation Mass Spectrometer and Camera-Microscope System for In Situ Investigation of the Composition and Morphology of Extra-terrestrial Materials (2014)
    Wiley-Blackwell
    Details
    Publication Date: 2014-11-11
    Description: Performance studies of a microscope-camera system (MCS) and a laser ablation/ionisation mass spectrometer (LIMS) instrument (referred to here as a laser mass spectrometer or LMS) are presented. These two instruments were designed independently for in situ analysis of solids on planetary surfaces and will be combined to a single miniature instrument suite for in situ chemical and morphological analysis of surface materials on planetary bodies. LMS can perform sensitive chemical (elemental, isotope and molecular) analyses with spatial resolution close to micrometre-sized grains. It allows for studies with mass resolution (M/ΔM) up to 800 in ablation mode (elemental composition) and up to 1500 in desorption mode (molecular analysis). With an effective dynamic range of at least eight orders of magnitude, sensitive and quantitative measurements can be conducted of almost all elements and isotopes with a concentration larger than a few ng g −1 . Hence, in addition to the major element composition, which is important for the determination of mineralogical constituents of surface materials, trace elements can also be measured to provide information on mineral formation processes. Highly accurate isotope ratio measurements can be used to determine in situ geochronology of sample material and for investigations of various isotope fractionation processes. MCS can conduct optical imagery of mm-sized objects at several wavelengths with micrometre spatial resolution for the characterisation of morphological surface details, and to provide insight to surface mineralogy. Furthermore, MCS can help in the selection of sample surface areas for further mass spectrometric analysis of the chemical composition. Surface auto-fluorescence measurements and images in polarised light are additional capabilities of the MCS, to identify either fluorescing minerals or organic materials, if present on the analysed surface, for further investigation by LMS. The results obtained by investigations of NIST reference materials, amino-acid films and a natural graphite sample embedded in silicate rock are presented to illustrate the performance of the instruments and their potential to deliver chemical information for mineral and organic phases in their geological context This article is protected by copyright. All rights reserved.
    Print ISSN: 1639-4488
    Electronic ISSN: 1751-908X
    Topics: Geosciences
    Published by Wiley-Blackwell
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  • 5
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    Towards quantification of pulsed spinlock and CEST at clinical MR scanners: an analytical interleaved saturation–relaxation (ISAR) approach (2014)
    Wiley-Blackwell
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    Publication Date: 2014-10-19
    Description: Off-resonant spinlock (SL) enables an NMR imaging technique that can detect dilute metabolites similar to chemical exchange saturation transfer. However, in clinical MR scanners, RF pulse widths are restricted due to recommended specific absorption rate limits. Therefore, trains of short RF pulses that provide effective saturation during the required irradiation period are commonly employed. Quantitative evaluation of spectra obtained by pulsed saturation schemes is harder to achieve, since the theory of continuous wave saturation cannot be applied directly. In this paper we demonstrate the general feasibility of quantifying proton exchange rates from data obtained in pulsed SL experiments on a clinical 3 T MR scanner. We also propose a theoretical treatment of pulsed SL in the presence of chemical exchange using an interleaved saturation–relaxation approach. We show that modeling magnetization transfer during the pauses between the RF pulses is crucial, especially in the case of exchange rates that are small with respect to the delay times. The dynamics is still governed by a monoexponential decay towards steady state, for which we give the effective rate constant. The derived analytical model agrees well with the full numerical simulation of the Bloch–McConnell equations for a broad range of values of the system parameters. Copyright © 2014 John Wiley & Sons, Ltd. Saturation of a two-pool-CEST system by pulsed spinlock can be modeled by an interleaved saturation–relaxation (ISAR) approach. Taking into account the chemical exchange during the pause is crucial, and leads to an analytical solution that agrees well with the full numerical simulation of the Bloch–McConnell equations for a broad range of values of the system parameters. This analytical solution allows the quantitative evaluation of Z -spectra obtained from creatine model solutions on a clinical 3 T scanner.
    Print ISSN: 0952-3480
    Electronic ISSN: 1099-1492
    Topics: Medicine
    Published by Wiley-Blackwell
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