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  • 1
    Electronic Resource
    Electronic Resource
    Conformational study of phosphoserine in aqueous solution. I - 13C n.m.r. results (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 9 (1977), S. 504-507 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 13C chemical shifts and coupling constants of phosphoserine in aqueous solutions were studied as a function of pH values. Carboxyl and α-amino titration shifts agree with those observed in amino acids. The analysis of the coupling constants indicates that for rotation about the (C)—C—O—(P) axis the trans conformer predominates for all pH values. The fractional population of the gauche conformer reaches a maximum at pH=8.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270090903
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  • 2
    Electronic Resource
    Electronic Resource
    Conformational study of phosphoserine in aqueous solutions. II - 1H n.m.r. results (1977)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 10 (1977), S. 26-30 
    Details
    ISSN: 0030-4921
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The 270 MHz n.m.r. spectra of phosphoserine (PSer) have been measured and completely analysed for seven pD values. The resulting vicinal coupling constants 3J(HαHβ) and 3J(PHβ) are used to discuss the conformations of PSer with respect to the (Hα)—Cα—Cβ—(O) and (Cα)—Cβ—O—(P) bond axes. The all-trans conformer predominates for all pD values, with its fractional population being minimal at pD values close to neutrality. The Cβ—O bond rotamer populations agree reasonably well with those obtained from 13C investigations.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1270100108
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  • 3
    Electronic Resource
    Electronic Resource
    Di-μ-hydrido-bis[1,3-propanbis(dicyclohexylphosphin)]dinickel(Ni—Ni)  -  Der Bindungszustand in einem Dreizentren-Wasserstoff-überbrückten Ni—Ni-System (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 3900-3909 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Di-p-hydrido-bis[1,3-propanbis(dicyclohexylphosphin)]dinickel(Ni—Ni) - Der Bindungszustand in einem Dreizentren-Wasserstoff-überbrückten Ni—Ni-SystemDie Kristallstruktur der Titelverbindung [(C6H11)2PCH2CH2CH2P(C6H11)2NiH]2 (1) wurde aus 4051 Reflexen abgeleitet und zu einem R-Wert von 0.044 verfeinert. Lageparameter aller Wasserstoffatome konnten einer Differenz-Fourier-Synthese entnommen werden. Die Struktur der diamagnetischen Verbindung setzt sich aus zwei P2Ni-Untereinheiten zusammen, welche zweifach mit Wasserstoffatomen (Ni—H 1.6 Å) überbrückt sind. Hierdurch ergibt sich ein bindender Ni—Ni-Abstand von 2.441(1) Å. Im Kristallgitter bilden die Ebenen durch die P2Ni-Untereinheiten einen Interplanarwinkel von 63.3°. Theoretische Betrachtungen sagen für das freie Molekül eine quadratisch planare Anordnung voraus, doch ergibt sich für die Drehbewegung zur beobachteten Geometrie nur eine flache Potentialenergiefläche. Die gefundene Verdrillung resultiert aus starken intramolekularen Abstoßungskräften zwischen den Cyclohexylgruppen der zwei P2Ni-Einheiten.
    Notes: The crystal structure of the title compound, [(C6H11)2PCH2CH2CH2P(C6H11)2NiH]2 (1), has been determined from 4051 reflections and refined to a final R-value of 0.044. The positions of the hydrogen atoms (bridging and non-bridging) have been determined from a difference Fourier synthesis. The molecular structure of the diamagnetic compound consists of subunits doubly-bridged by hydrogen atoms. The Ni—Ni and average Ni—H distances are 2.441 and 1.6 Å, respectively. In the solid state the two planes of the P2Ni units form a dihedral angle of 63.3°. Theoretical considerations predict a square-planar structure for the idealized molecule with a soft potential energy surface for a twisting motion towards the observed geometry. The observed twist is the result of severe intramolecular repulsions between the cyclohexyl groups of the two P2Ni units.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771101221
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  • 4
    Electronic Resource
    Electronic Resource
    Difluorophosphate von Zinn(IV) und Antimon(V) (1978)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 438 (1978), S. 169-175 
    Details
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Difluorophosphates of Tin (IV) and Antimony(V)Preparation and properties of SnCl2(PO2F2)2 (l), Cl4Sb(O2PF2) (2) and F4Sb(O2PF2) (3) are described. According to their vibrational spectra the structures are assumed. 31P-nmr spectra of 2 and 3 are given. 1 is characterised additional by its 119Sn-Mössbauer spectrum.
    Notes: Darstellung und Eigenschaften von SnCl2(PO2F2)2 (1), SbCl4(PO2F2) (2) und F4Sb(O2PF2) (3) werden beschrieben. Aus den Schwingungsspektren werden Strukturvorschläge abgeleitet. 31P-KMR-Spektren werden für 2 und 3 mitgeteilt, 1 wird zusätzlich durch das 119Sn-Mößbauer-Spektrum charakterisiert.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19784380118
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  • 5
    Electronic Resource
    Electronic Resource
    Massenspektrometrische Fragmentierung von Metallkomplexen des Tropolons (1977)
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 12 (1977), S. 727-731 
    Details
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: The fragmentation of metal complexes of tropolones is decisively infleunced by the metal atom. In contrast to the free ligand the elimination of carbon monoxide is greatly reduced. The formation of the metal-free fragments is commented upon, as well as the unusual elimination of water from the Cu derivative.
    Notes: Die Fragmentierung der Metallkomplexe von Tropolonen ist entscheidend vom Metallatom beeinflußt. Im Unterschied zum freien Liganden wird die Eliminierung von Kohlenmonoxid stark zurückgedrängt. Die Bildung von metalltreien Fragmentionen sowie die außergewöhnliche Wasserabspaltung der Cu-Verbindung werden beschrieben.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/oms.1210121204
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  • 6
    Electronic Resource
    Electronic Resource
    Organische Synthesen mit Übergangsmetallkomplexen, 8. Untersuchungen zur Synthese ungesättigter δ-Lactone durch Cyclocarbonylierung von Vinyloxiranen mit Übergangsmetall-Komplexen (1979)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 3644-3671 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Organic Syntheses by Means of Transition Metal Complexes, 8 - Synthesis of Unsaturated δ-L-Lactones from Vinyloxiranes and Carbon Monoxide via Transition Metal ComplexesThe transition metal-assisted carbonylation of vinyloxiranes to unsaturated δ-lactones has been verified and studied mechanistically by use of organometallic model reactions. The light induced complexation of vinyloxiranes 1 by Fe(CO)5 was shown to be a multistep reaction in which diastereomeric cis-resp. trans- ferralactones 2 are formed. Complexes of both types (2k, 2k′) were characterized crystallographically and studied chemically concerning their reactions with nucleophiles and electrophiles. Reaction with primary amines gives ferralactames 7 by migration of the allyl group and inversion at C-1 as well as C-4 indicating an attack of amine at the exo-position of C-4. On the other hand the reaction with HO⊖ leads to the formation of CO23⊝ and diene complexes 10 with inversion at C-1 only, indicating that the reaction has been initiated by attack of HO⊖ at a terminal carbonyl group. On electrophilic attack ferralactones form allyl cations (14, 16) by opening of the CO - O bond. Carbonylation of ferralactones with CO in aprotic solvents give good yields of unsaturated δ-lactones (12). In the case of isoprene epoxide it has been shown that homogeneous catalytic cyclocarbonylation of vinyloxiranes can be of synthetic use.
    Notes: Anhand metallorganischer Modellreaktionen wurde die Cyclocarbonylierung von Vinyloxiranen zu ungesättigten δ-Lactonen untersucht. Die photochemisch initiierte Komplexierung von Vinyloxiranen 1 (X = O) an Fe(CO)5 verläuft mehrstufig und führt zu diastereomeren cis- bzw. trans-Ferralactonen 2. Vertreter beider Verbindungstypen (2k, 2 k′) wurden kristallographisch charakterisiert und chemisch bezüglich ihres Verhaltens gegenüber Nucleophilen und Elektrophilen studiert. Mit primären Aminen bilden sich Ferralactame 7 unter Wanderung des Allylsystems sowie unter Konfigurationsumkehr an C-1 und C-4, was den exo-Angriff des Amins an C-4 des Allylsystems beweist. Bei Einwirkung von HO⊝ hingegen zerfallen Ferralactone zu CO23⊝ und Dien-komplexen 10, wobei lediglich an C-1 eine Konfigurationsumkehr beobachtet wird. In diesem Fall greift HO⊝ somit an einer terminalen Carbonylgruppe an. Elektrophile bewirken die Spaltung der CO-O-Bindung unter Bildung von Allyl-Kationen (14, 16). Die Carbonylierung von Ferralactonen führt in aprotischen Lösungsmitteln in guten Ausbeuten zu ungesättigten S-Lactonen (12). Am Isoprenepoxid wurde gezeigt, daß auch die homogenkatalytische Cyclocarbonylierung von Vinyloxiranen gute Ausbeuten an δ-Lactonen ergibt und dieses Verfahren für Synthesen von Interesse ist.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19791121114
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  • 7
    Electronic Resource
    Electronic Resource
    Reactions of Carbon Dioxide with Allylnickel CompoundsThis work was supported by the Deutsche Forschungsgemeinschaft.-Atomic parameters and Fo/Fc lists of the X-ray structure analyses are obtainable on request from the authors (Goddard, Krüger, Sekutowski, Tsay). (1978)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 17 (1978), S. 124-125 
    Details
    ISSN: 0570-0833
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.197801241
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  • 8
    Electronic Resource
    Electronic Resource
    Strain-induced crystallization, Part IV: Induction time analysis (1979)
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 19 (1979), S. 401-405 
    Details
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: The empirical equation, 1/ti = AeEi/RT, which expresses the exponential dependence of the reciprocal of crystallization induction time, ti, has been analyzed and shown to be equivalent to the nucleation rate equations derived earlier in Part III (1). Consequently we have used the ti measurements obtained earlier by Krueger and Yeh to calculate not only the nucleation rate enhancements but also the melting point elevations, the relative crystal thickness changes and molecular coil extension ratios of shear-crystallization polyethylene. It is shown that polyethylene when crystallized between 129 and 131°C at shear rates between 1.56 and 9.70 sec-1 can have melting point increases of 4.2 to 7.2°C and crystal thickness decreases of 20 to 25 percent, when compared to those crystallized at 130°C in the quiescent state. The predicted “coil” extension in the melt just prior to shear-induced crystallization ranges between 21 and 36 percent. The results of these analyses as well as those on nucleation rates of polyethylene oxide are discussed in detail.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pen.760190606
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  • 9
    Electronic Resource
    Electronic Resource
    Untersuchungen zur Reaktivität von Metall-π-Komplexen, XXII. Sandwichartig gebaute (Pd-Pd)-Zweikernkomplexe mit brückenbildenden Cyclopentadienyl- und Allyl-Liganden (1977)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 110 (1977), S. 1763-1775 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Studies on the Reactivity of Metal π-Complexes, XXII. Sandwich-like Dinuclear (Pd-Pd)-Complexes with Bridging Cyclopentadienyl and Allyl LigandsThe reaction of C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-allyl) with tertiary phosphines or phosphites in the molar ratio of 1:1 produces in practically quantitative yields the dinuclear complexes (C5H5)(2-RC3H4)Pd2L2 (4-20) in which palladium has the oxidation state +1. The crystal structure analysis of 5 (R = CH3, L = P(C6H5)3) and 12 (R = CH3, L = P(OC6H4-o-CH3)3) shows that the cyclopentadienyl as well as the allyl ligand is bonded in a sandwich manner to the Pd-Pd unit. The Pd-Pd distance of 267.9 (in 5) or 268.9 pm (in 12) is suggestive of a metal-metal bond. It is not possible to determine whether the cyclopentadienyl ring in 4-20 exists as a pentahapto- or trihapto-bonded ligand on the basis of the 1H- and 13C n. m. r. data. The reactivity of the dinuclear complexes is in agreement with square planar coordination of the metal atoms.
    Notes: Bei den Reaktionen von C5H5Pd(2-RC3H4) (2-RC3H4 = 2-R-Allyl) mit tertiären Phosphinen oder Phosphiten im Molverhältnis 1:1 entstehen in praktisch quantitativer Ausbeute die Zweikernkomplexe (C5H5)(2-RC3H4)Pd2L2 (4-20), in denen Palladium in der Oxidationszahl +1 vorliegt. Wie die Kristallstrukturanalysen von 5 (R = CH3, L = P(C6H5)3) und 12 (R = CH3, L = P(OC6H4-o-CH3)3) zeigen, sind sowohl der Cyclopentadienyl- als auch der Allyl-Ligand sandwichartig an die Pd2-Einheit gebunden. Der Pd-Pd-Abstand von 267.9 (in 5) bzw. 268.9 pm (in 12) weist auf das Vorliegen einer Metall-Metall-Bindung hin. Aufgrund der 1H- und 13C-NMR-Daten ist nicht zu entscheiden, ob in 4-20 der Cyclopentadienylring als pentahapto-oder trihapto-gebundener Ligand vorliegt. Die Reaktivität der Zweikernkomplexe steht mit einer quadratisch-planaren Koordination der Metallatome in Einklang.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19771100522
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