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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 2615-2625 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur(IV) Compounds as Ligands, 1. Carbonyl Chromium, Molybdenum, and Tungsten Complexes of Sulfur DioxideComplexes cis-M(CO)4(L)SO2(M = Cr, Mo, W;L = CO, P(CH3)3), P(C6H5)2CH3, P(OCH3)3) and mer-M(CO)3(C6H5)2PC2H4P(C6H5)2SO2 (M = Cr, Mo, W) containing η1-planar coordinated sulfur dioxide are described. η2 Coordination of sulfur dioxide is found in fac-Mo(CO)3-(C6H5)2PC2H4P(C6H5)2SO2. The proton catalyzed fac-mer isomerization of this derivative is the first example of linkage isomerization of sulfur dioxide caused by a change of the coordination geometry around the metal. The coordinated sulfur dioxide is readily displaced by Lewis bases.
    Notes: Komplexe cis-M(CO)4(L)SO2 (M = Cr, Mo, W;L = CO, P(CH3)3), P(C6H5)2CH3, P(OCH3)3) und mer-M(CO)3(C6H5)2PC2H4P(C6H5)2SO2 (M = Cr, Mo, W) mit η1-planar gebundenem Schwefeldioxid werden beschrieben. η2-Koordiniertes Schwefeldioxid liegt in fac-Mo(CO)3-(C6H5)2PC2H4P(C6H5)2SO2 vor. Die protonenkatalysierte fac-mer-Isomerisierung dieses Derivates ist das erste Beispiel für eine nur durch änderung der Geometrie am Metall hervorgerufene Bindungsisomerisierung an einem Schwefeldioxid-Komplex. Das koordinierte Schwefeldioxid wird von Lewis-Basen leicht substituiert.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 115 (1982), S. 3618-3630 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonyl Monoolefin Derivatives of the Group VI Transition Metals, III. Preparation and Reaction and Reactivity of Tricarbonyl Chelate Phosphane Olefin DerivativesMonoolefin complexes M(CO)3(R2PC2H4PR2)(ol) (M = Cr, Mo, W; R = CH3, C6H5; ol = maleic anhydride, dimethyl fumarate, dimethyl maleate, methyl acrylate, ethylene, styrene, norbornene) are obtained photochemically from the tetracarbonyl chelate phosphane derivatives. Facial complexes are formed primarily, some of which rearrange intramolecularly to the meridional isomers. The substitution of the olefin proceeds via a dissociative mechanism, the meridional isomers rearrange back to the facial ones prior to the rupture of the metal-olefin bond.
    Notes: Monoolefin-Komplexe M(CO)3(R2PC2H4PR2)(ol) (M = Cr, Mo, W; R = CH3, C6H5; ol = Maleinsäureanhydrid, Dimethylfumarat, Dimethylmaleat, Methylacrylat, Ethylen, Styrol, Norbornen) sind photochemisch aus den Tetracarbonyl-Chelatphosphan-Derivaten zugänglich. Es entstehen zunächst faciale Komplexe, die sich zum Teil rasch intramolekular in die meridionalen Isomeren umlagern. Die Substitution des Olefins verläuft nach einem dissoziativen Mechanismus, der Spaltung der Metall-Olefin-Bindung geht bei den meridionalen Derivaten die intramolekulare meridional-facial-Isomerisierung voraus.
    Additional Material: 1 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 31 (1980), S. 41-46 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Measurements of nuclear magnetic relaxation times T1, T1ϱ, T2e and T2 of PVC were realized using different pulse methods in a region from 123 K up to 573 K. The variation of several parameters of experiments allows the determination of characteristic frequencies of molecular reorientation. The WLF-plot of these transition frequencies and temperatures agrees with the glass transition curve of PVC, based on a special thermodynamic theory (scaling concept). Some relaxation effects are discussed shortly applying well known theoretical aspects for different temperature and frequency regions.
    Notes: Die Messung der kernmagnetischen Relaxationszeiten T1, T1ϱ, T2e und T2 von PVC erfolgt durch die Anwendung verschiedener Impulsverfahren im Temperaturbereich von -150°C bis 200°C. Durch Variation verschiedener Meßparameter werden charakteristische Molekülumlagerungsfrequenzen ermittelt, deren Temperaturlagen in die WLF-Darstellung des Glasüberganges von PVC auf der Grundlage einer speziellen thermodynamischen Theorie (Scaling-Konzeption) gut eingeordnet werden können. Eine Reihe von methodenspezifischen Relaxationseffekten wird unter Verwendung bekannter theoretischer Aspekte aus der Literatur für unterschiedliche Temperatur- und Frequenzbereiche kurz diskutiert.
    Additional Material: 5 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 477 (1981), S. 149-153 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Substituted Halocarbonyl Metallates of Chromium, Molybdenum, and Tungsten. IV. Crystal Structure of Tetramethylammonium ChloropentacarbonyltungstateThe structure of tetramethylammonium chloropentacarbonyltungstate has been determined from single crystal X-ray data. The compound crystallizes with four formula units in the monoclinic unit cell (space group P21/c) of the dimensions a = 1111.3(4) pm, b = 1110.3(4) pm c = 1204.1(3) pm, β = 99.63(3)°, V = 1464.8 × 106 pm3 (R = 0.028). The anion possesses approximately C4v symmetry with the principal interatomic distances d(W-C(cis)) = 203 pm, d(W-C(trans)) = 197 pm d(W-Cl) = 256.6 pm. No unusual contacts between cation and anion have been found.
    Notes: Die Struktur von Tetramethylammoniumchloropentacarbonylwolframat wurde röntgenographisch aus Einkristalldaten bestimmt. Die Verbindung kristallisiert mit vier Formeleinheiten in der monoklinen Elementarzelle (Raumgruppe P21/c) folgender Dimensionen: a = 1111,3(4) pm, b = 1110,3(4) pm, c = 1204,1(3) pm, β = 99,63(3)°, V = 1464,8 · 106 pm3 (R = 0,028). Das Anion besitzt annähernd C4v-Symmetrie mit d(W-C(cis)) = 203 pm, d(W-C(trans)) = 197 pm, d(W-Cl) = 256,6 pm. Zwischen Kation und Anion treten keine ungewöhnliche Kontakte auf.
    Additional Material: 3 Tab.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 502 (1983), S. 191-198 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Sulfur(IV) Compounds as Ligands. II. The Crystal and Molecular Structure of Pentacarbonyl--(sulfur dioxide)chromiumThe structure of pentacarbonyl(sulfurdioxide)chromium (1) has been determined from single crystal X-ray data. The compound crystallizes with eight formula units in the rhombic unit cell (space group Pbn21) of the dimensions a = 657.8(2) pm, b = 1245.2(4) pm, c = 2177.4(5) pm (at 180 K). The sulfur dioxide is η1-coplanar coordinated, the Cr—S distance is 219 pm, the shortest bond reported so far between chromium(0) and sulfur. The Cr—C(ax) bond (189 pm) was found only marginally shorter than the Cr—C(eq) bonds (190 pm) providing proof of the high π-acceptor capacity of SO2.
    Notes: Die Struktur von Pentacarbonyl(schwefeldioxid)chrom (1) wurde röntgenographisch aus Einkristalldaten bestimmt. Die Verbindung kristallisiert mit acht Formeleinheiten in der rhombischen Elementarzelle (Raumgruppe Pbn21) folgender Dimensionen: a = 657,8(2) pm, b = 1245,2(4) pm, c = 2177,4(5) pm (bei 180 K). Das Schwefeldioxid ist η1-koplanar koordiniert, der Cr—S-Abstand ist mit 219 pm der kürzeste bisher gefundene Abstand zwischen Chrom(0) und Schwefel. Die Cr—C(ax)-Bindung ist mit 189 pm fast genau so lang wie die Cr—C(eq)-Bindungen (190 pm), ein Beleg für das hohe π--Akzeptorvermögen des SO2.
    Additional Material: 2 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 478 (1981), S. 205-214 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Carbonyl Monoolefin Derivatives of the Group VI Transition Metals. I. Tetracarbonyl Phosphine Olefin ComplexesMonoolefin complexes cis-M(CO)4(PR3)(olefin) (M = Cr, Mo, W; R = Et, Bu, Pri, Ph; olefin = maleic anhydride, dimethyl maleate, dimethyl fumarate, bis(trimethylsilyl) fumarate, ethylene) are obtained from the ionic compounds Et4N[R3PM(CO)4Cl] either via ethanol or acetonitrile derivatives M(CO)4(PR3)L, or directly in a two phase system. The olefins are displaced by Lewis-bases such as amines or phosphines under mild conditions.
    Notes: Monoolefin-Komplexe cis-M(CO)4(PR3)(olefin) (M = Cr, Mo, W; R = Et, Bu, Pri, Ph; olefin = Maleinsäureanhydrid, Dimethylmaleat, Dimethylfumarat, Bis(trimethylsilyl)fumarat, Ethylen) sind aus den ionischen Verbindungen Et4N[R3PM(CO)4Cl] entweder über Ethanol- oder Acetonitrilderivate M(CO)4(PR3)L oder direkt im Zweiphasensystem zugänglich. Die Olefine werden von Lewis-Basen wie Aminen oder Phosphinen unter milden Bedingungen substituiert.
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  • 7
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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  • 8
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
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