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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 49 (1976), S. 23-48 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: The progress of ultrasonic degradation of polymers in solution can be described theoretically by the aid of the model of pearlstring molecules. According to this molecular model macromolecules are built up like a pearl necklace of so-called tertiary structural units. There is correlation between molecular weight of structural units to be obtained by measuring electron micrographs and limiting molecular weight after ultrasonic degradation.Experimental results suggest that molecules resembling a string of pearls are broken at the chain between its spherical units. Two imaginable ways of degradation mechanism are discussed: fragmentary and stepless depolymerization. In the first case the chain is broken between its structural units in several steps; in the second case the pearlstring molecule is broken to all its units in one step. Mathematical consideration has provided an equation for the stepless mechanism. By the aid of this equation the complete progress of depolymerization can be calculated if the limiting molecular weight after ultrasonic degradation is known. On the other hand the limiting molecular weight may be calculated if the beginning of degradation is known. Stepless and fragmentary degradation can be distinguished by comparing the experimentally determined depolymerization with the calculated one.
    Notes: Um Aufschluß über Kinetik und Mechanismus der Ultraschall-Depolymerisation zu erhalten, wurde der Versuch unternommen, den zeitlichen Ablauf des Abbaus auf der Grundlage des Perlschnurmolekül-Modells theoretisch zu beschreiben. Nach diesem molekularen Modell sind Makromoleküle - ähnlich einer Perlschnur - aus mehreren, näherungsweise sphärischen, einheitlich und für ein gegebenes Polymeres charakteristisch großen sog. Tertiäreinheiten aufgebaut.Für den Ultraschall-Abbau von Perlschnurmolekülen werden zwei verschiedene Mechanismen diskutiert: der fragmentarische, bei dem die Perlschnurmoleküle stufenweise über Bruchstücke nach und nach zu den Tertiäreinheiten abgebaut werden und der stufenlose, bei dem die Depolymerisation der Perlschnurmoleküle unmittelbar zu den Tertiäreinheiten führt, so daß während des Abbaus nur Moleküle vom Anfangs- und Grenzmolekulargewicht, M0 und M∞, auftreten. Die mathematische Behandlung des stufenlosen Abbaus lieferte folgende Beziehung: \documentclass{article}\pagestyle{empty}\begin{document}$ \overline {\rm M} _{\rm i} = {\rm M}_{\rm 0} \cdot {\rm M}_\infty \left[ {{\rm M}_{\rm 0} - \left( {{\rm M}_0 - {\rm M}_\infty } \right) \cdot \left( {1 - \pi } \right)^{\rm i} } \right]^{ - 1} . $\end{document} Mit Hilfe dieser Abbaugleichung lassen sich bei Kenntnis von M0, M∞ und eines einzigen Mi-Wertes, der zur Berechnung der „Zertrümmerungskonstanten“ π erforderlich ist, Abbaukurven Mi=f (Beschallungszeit i), oder umgekehrt bei Kenntnis nur des Anfangs einer experimentellen Abbaukurve Grenzmolekulargewichte berechnen. Durch Vergleich der berechneten Abbaukurve mit der experimentell bestimmten ist es möglich, zwischen stufenlosem und fragmentarischem Abbau zu unterscheiden.
    Additional Material: 13 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 48 (1976), S. 345-345 
    ISSN: 0009-286X
    Keywords: Abwasserreinigung ; Tenside ; Schaumtrennung ; Blasenkolonne ; Recycling ; II-Theorem ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 2 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Biological Mass Spectrometry 11 (1976), S. 458-467 
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The loss of water from the molecular ion of 2-adamantanol was investigated using specifically labelled deuterium derivatives, and, in particular that stereospecifically labelled in position 4. Water is lost predominantly in a stereospecific 1, 3 fashion by two clearly distinguishable mechanisms. Determination of metastable ion characteristics proved to be essential for drawing this distinction.
    Additional Material: 2 Ill.
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  • 4
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reactivity differences between odd ([M]+) and even electron ions (α-cleavage product) were studied by comparing water elimination mechanisms in 6-undecanol. The compounds specifically labelled with deuterium in positions 6, 5 + 7, 4 + 8 and 3 + 9 were made, and a detailed investigation of tghe metastable ion transitions carried out. A highly specific 1,4 elimination of water without preceding intramolecular hydrogen exchange occurs from [M]+, but equal amounts of 1,3 and 1,4 elimination of water preceded by specific hydrogen exchange between -OH and the hydrocarbon chain occurs from the α-cleavage ion [M - C5H11]+. To make such distinctions a thorough examination of metastable ions is essential.
    Additional Material: 3 Ill.
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  • 5
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes with Anionic Ligands of Main Group IV Elements. XI. Substitution Reactions of Trichlorogermide and Trichlorostannide Ions with Metaltrifluorophosphine ComplexesThe photochemical reactions of [SnCl3]- in THF with the metal(0)-trifluorophosphine complexes of Ni, Fe, and Mo result in [Ni(PF3)3SnCl3]-, [Fe(PF3)3(SnCl2]-, and [Mo(PF3)5SnCl3]-. [GeCl3]-, in substitution reactions not as reactive as [SnCl3]-, does react under similar conditions with Fe(NO)2(PF3)2 only, to yield [Fe(NO)2(PF3)GeCl3]-. With CpMn(PF3)3 (Cp = h5-C5H5) by the intermediatly formed CpMn(PF3)2THF both substitution derivatives [CpMn(PF3)2ECl3]- (E = Ge, Sn) are found. The metallate(0) complexes are isolated as [As(C6H5))4]+- and [N(C2H5)4]+ -salts; the i.r.- and 19F-n.m.r.-spectra are reported.
    Notes: Unter UV-Bedingungen in THF liefern [SnCl3]--Ionen mit den Metall(0)-trifluorphosphinen von Nickel, Eisen und Molybdän die Metallat(0)-Komplexe [Ni(PF3)3SnCl3]-, [Fe(PF3)3(SnCl3)2]2- und [Mo(PF3)5SnCl3]-. Hingegen bildet das bei Substitutionsreaktionen hinter dem [SnCl3]-. Ion zurückstehende [GeCl3]-.-Ion unter ähnlich drastischen Bedingungen lediglich mit Fe(NO)2(PF3)2 das Monosubstitutionsprodukt [Fe(NO)2(PF3)GeCl3]-. Aus CpMn(PF3)3 (Cp = h5-C5H5) sind über den intermediär gebildeten Komplex CpMn(PF3)2THF beide Substitutionsderivate [CpMn(PF3)2ECl3]- (E=Ge, Sn) leicht zugänglich. Die Metallatkomplexe werden als [As(C6H5)4]+- bzw. [N(C2H5)4]+ -Salze isoliert; ihre IR- und 19F-NMR-Daten werden mitgeteilt.
    Additional Material: 1 Tab.
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  • 6
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 116-126 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Substituted Phosphonates. XIX. Derivatives of Aminomethane-bis-phosphonic AcidAminomethane-bis-phosphonic acid tetraethylesters have been prepared by various methods. Chlorination and hydrolysis of these compounds have been studied in detail.
    Notes: Aminomethan-bis-phosphonsäure-tetraäthylester wurden nach verschiedenen Verfahren synthetisiert. Die Chlorierung und die Hydrolyse dieser Verbindungen wurden eingehend untersucht.
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  • 7
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Metal Complexes with Anionic Ligands of the Main Group IV Elements. IX. Reactions of Trichlorostannide and Trichlorogermide Ions with Complexes of Transition Metals in Low Oxidation StatesCarhonyl trichlorostannido- and carbonyl trichlorogermido-metalate complexes have been synthesized both by photochemical and thermical substitution reactions of [ECl3]- ions (E = Sn, Ge) with M(CO)6, (M = Cr, Mo, W), Fe(CO)5 Fe3(CO)12, Co2(CO)8, as well as with the metalcarbonyl derivatives (π-arene)M(CO)3, (M = Cr, Mo), (h5-C5,H5,)V(CO)4, Mn(CO)5,Cl, Co(NO)(CO)3, and Fe(NO)2,(CO)2. Mainly the bonding properties of the [ECl3]- ligands are discussed by means of i.r. spectroscopic investigations. The progress of the reactions and the necessary reaction conditions show that the nucleophilic properties oft both anions [ECl3]- are unexpectedly small. The slightly weaker hasicity of [SnCl3]- compared with [GeC13]- arreared, when both anions were reacted with Co2,(CO)8, forming the substitution product. [Co2,(CO)7,SnCl3]- and the products of a “base reaction” Cl3GcCo(CO)4, and [Co(CO)4]-.
    Notes: Unter photochemischen wie auch thermischen Bedingungen werden insbesondere Carbonyl-trichlorstannido (bzw. trichlorgermido)-metallat-Komplexe durch Substitutionsreaktionen von [SnCl3]-- bzw. [GeCl3]--Ionen an den Metallcarbonylen M(CO)6 (M = Cr, Mo, W), Fe(CO)5, Fe3(CO)12 und Co2(CO)8 sowie an den Metallcarbonylderivaten π-ArenM(CO)3 (M = Cr, Mo), (h5-C5H5)V(CO)4, Mn(CO)5Cl, Co(NO)(CO)3 und Fe(NO)2(CO)2 dargestellt und als [N(C2H5)4]+ - bzw. [As(C6H5)4]+-Salze isoliert. Anhand der IR-Spektren werden ihre Bindungsverhältnisse diskutiert. Aus den Reaktionsabläufen und den hierzu erforderlichen Reaktionsbedingungen darf eine unerwartet geringe Nukleophilie der beiden [ECl3]--Liganden (E = Ge, Sn) abgeleitet werden. Obgleich das Trichlorstannid-Ion  -  das mit Oktacarbonyldikobalt immerhin noch das Substitutionsprodukt [Co2(CO)7SnCl3]- liefert, während [GeCl3]- unter analogen Bedingungen bereits eine „Basenreaktion“ zum Cl3GeCo(CO)4 und [Co(CO)4]- indiziert  -  im Vergleich zum Trichlorgermid-Ion die am schwächsten ausgeprägte Basizität besitzt, kann ein prinzipiell unterschiedliches komplexchemisches Reaktionsverhalten beider Anionen nicht festgestellt werden.
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  • 8
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 318 (1976), S. 157-160 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: α-Aminoacids and Derivatives. VIII. A Simple Synthesis of PhosphinothricinA simple and economical synthesis of D,L-phosphinothricin 2 - the active part of an antibiotical effective heterotripeptide which was isolated from Streptomyces viridochromogenes - is described.
    Notes: Es wird eine einfache und ökonomische Synthese von D, L-Phosphinothricin 2, dem wirksamen Bestandteil eines aus Streptomyces viridochromogenes isolierten antibiotisch wirksamen Heterotripeptids beschrieben.
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  • 9
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Letters Edition 14 (1976), S. 114-115 
    ISSN: 0360-6384
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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