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  • 1
    Electronic Resource
    Electronic Resource
    Radikalbildung aus Hydroperoxiden in Gegenwart starker SäurenHerrn Prof. Dr. D. Braun zum 60. Geburtstag gewidmet (1991)
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 185 (1991), S. 43-50 
    Details
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The polymerisation of styrene and methylacrylate initiated by hydroperoxides is accelerated in the presence of strong acids such as sulfuric acid, p-toluene-sulfonic acid or perchloric acid. By copolymerising styrene and methylmethacrylate and by phenolic type inhibitors the radical nature of the catalytic effect of the acid was proved. Kinetic experiments demonstrated the acid involvement in the starting reaction.
    Additional Material: 4 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/apmc.1991.051850105
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  • 2
    Electronic Resource
    Electronic Resource
    Neuartige basische Liganden für die homogenkatalytische Methanolcarbonylierung, IX1) Synthese und Reaktivität von Ruthenium(II)-Komplexen mit Ether-Phosphan-Liganden (1987)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 120 (1987), S. 1621-1628 
    Details
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Novel Basic Ligands for the Homogeneous Catalytic Methanol Carbonylation, IX1). -Synthesis and Reactivity of Ruthenium(II) Complexes with Ether Phosphane LigandsThe ether phosphane ligands R2P↷D (2a-d) react with RuCl3·3H2O (1) to give the complexes Cl2Ru(R2P↷D)2 (3a-d) in which the P,O ligands 2a-d function as bidentates. With CO one Ru-O bond is ruptured with formation of trans-Cl2-(R2P∼D)(R2P↷D)RuCO (4a-d). Upon introduction of a second CO molecule in 4a, b, also the other Ru-O bond is cleaved. On heating the kinetically controlled products all-trans-RuCl2(CO)2(R2P∼D)2 (all-trans-5a, b) are transformed into the thermodynamically more stable complexes cis-Cl2(OC)2Ru(trans-R2P˜D)2 (cis,cis,trans-5a, b). All reaction steps are reversible. Upon irradiation cis,cis,trans-5a, b are retransformed into 3a, b via all-trans-5a, b and 4a, b. The opening and closing mechanism of the P,O ligands 2a, b is observed by IR and 31P{1H} NMR spectroscopy. According to X-ray structural analyses, 3b and 4b crystallize in the monoclinic and triclinic space group P21/n and P1 with Z = 4 and 2, respectively. 4b catalyses the hydrogenation of acetaldehyde to ethanol.
    Notes: Die Ether-Phosphan-Liganden R2P↷D (2a-d) reagieren mit RuCl3·3H2O (1) zu den Komplexen Cl2Ru(R2P↷D)2 (3a-d), in denen die P,O-Liganden 2a-d zweizähnig fungieren. Mit CO wird eine Ru-O-Bindung geöffnet unter Bildung von trans-Cl2-(R2P↷D)(R2P↷D)RuCO (4a-d). Bei der Einführung eines zweiten CO-Moleküls in 4a, b läßt sich auch die andere Ru—O-Bindung spalten. Die kinetisch gelenkt entstehenden Produkte all-trans-RuCl2(CO)2(R2P∼D)2 (all-trans-5a, b) wandeln sich beim Erwärmen in die thermodynamisch stabileren Komplexe cis-Cl2(OC)2Ru(trans-R2P∼D)2 (cis,cis,trans-5a, b) um. Alle Reaktionschritte sind reversibel. Beim Bestrahlen wandeln sich cis,cis,trans-5a, b über all-trans-5a, b und 4a, b in 3a, b zurück. Der Auf- und Zuklappmechanismus der P, O-Liganden 2a, b kann IR- und 31P{1H}-NMR-spektroskopisch verfolgt werden. Nach Röntgenstrukturanalysen kristallisieren 3b und 4b in der monoklinen bzw. triklinen Raumgruppe P21/n bzw. P1 mit Z = 4 bzw. 2. 4b katalysiert die Hydrierung von Acetaldehyd zu Ethanol.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19871201005
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  • 3
    Electronic Resource
    Electronic Resource
    Functionalized Ether Derivatives of HOCH2C(CH2PPh2)3 and Related Tripod Ligands - Synthesis and Coordination Chemistry (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 1407-1415 
    Details
    ISSN: 1434-1948
    Keywords: Functionalized tripod ligands ; Mixed donor set ligands ; Solubilized tripod ligands ; Molybdenum ; Iron ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Neopentane-derived tripod ligands of the general type HOCH2C(CH2PPh2)(CH2Y)(CH2Z) (1; Y, Z = PPh2, SR) are notoriously resistant to ether formation at their hydroxy group. Two routes have been found, which allow the transformation of 1 into ether functionalized tripod ligands ROCH2C(CH2PPh2)(CH2Y)(CH2Z) (Y = Z = PPh2: 5, Y = Z = SR: 8). One of these strategies relies upon the η3 coordination of 1 in 1·Mo(CO)3 (2). By this way the donor groups are efficiently protected and the steric encumbrance of the CH2OH group at the backbone of the ligands is greatly reduced by fixing three arms of the neopentane scaffolding to the metal center. After deprotonation, reaction with electrophiles will produce the corresponding ether derivatives ROCH2C(CH2PPh2)(CH2Z)2 (3). Mesylation of 2 leads to MeSO2OCH2C(CH2PPh2)3·Mo(CO)3 (4), which reacts with alkoxides to produce 3 in a sequence of reversed polarity. Ligands 5 [ROCH2C(CH2PPh2)3] are liberated from 3 by UV irridation of their solutions in the presence of pyridine N-oxide. Direct etherification of 1 is also possible in some cases after deprotonation of 1 by KOtBu and subsequent reaction with an electrophile RX in the narrow temperature range between -10 and +20 °C. By this way, ω-methyl polyglycol ether functions are easily introduced resulting in H3C(OC2H4)nOCH2C(CH2PPh2)3 (5g, h).
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    How to Predict Activation Barriers - Conformational Transformations of Compounds CH3C(CH2PPh2)3-n[CH2P(oTol)2]nMo(CO)3 (n = 1-3): Force Field Calculations versus NMR Data (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 597-615 
    Details
    ISSN: 1434-1948
    Keywords: Tripod molybdenum tricarbonyl compounds ; Conformational analysis in solution ; Dynamic NMR ; Force field calculations ; Activation barriers ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Tripod metal entities tripodM are sterically congested systems. The conformations adopted by compounds CH3C(CH2PPh2)3-n[CH2P(oTol)2]nMo(CO)3 (n = 1: 1, n = 2: 2, n = 3: 3) will thus be largely determined by the repulsive forces acting in these molecules. The steric demand of the o-tolyl groups impedes their free rotation and enantiomerization processes referring to the compounds as a whole are sufficiently slow to permit their analysis by NMR techniques. Through a combination of line-shape analysis, EXSY methods, and coalescence experiments, the ΔG
    Additional Material: 20 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Magnetic Interaction in Dinuclear Triphos-Cobalt Complexes with Co···Co Separations of 8 and 10 Å (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 183-189 
    Details
    ISSN: 1434-1948
    Keywords: Tripodal ligands ; Cobalt complexes ; Bridging ligands ; Exchange coupling ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Weak antiferromagnetic exchange interactions are observed in two CoII dimers of the general formula [{(triphos)Co}2(μ-dicarboxylato)](BF4)2 where the dicarboxylate is the dianion of fumaric acid [3 ·(BF4)2] or terephthalic acid [4 ·(BF4)2] and triphos is the tridentate phosphorus ligand 1,1,1-tris(diphenylphosphanomethyl)ethane. In these complexes the metal ions are separated by 8 and 10 Å, as determined by X-ray crystallography. Insight into the interaction pathway is gained through molecular orbital calculations performed on model compounds. The influence of bridging-ligand distortions and the stereochemistry around the two cobalt centres is discussed.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Korrosionsverhalten rostfreier Stähle gegenüber halogenhaltigen Lösungsmitteln (1982)
    Weinheim [u.a.] : Wiley-Blackwell
    Materials and Corrosion/Werkstoffe und Korrosion 33 (1982), S. 404-410 
    Details
    ISSN: 0947-5117
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Description / Table of Contents: Corrosion behaviour of stainless steels in halogen containing solutions.Halogenated hydrocarbons are widely used for cleaning metallic objects. Since solvents of this type undergo hydrolyzation in presence of water, serious damage is apprehended especially for alloys known to be sensitive against chloride-induced stress corrosion.These tests were intended to check the risk of corrosion when halogenated hydrocarbons are used as a solvent for cleaning metallic surfaces, and if a residual fluid - trapped within small crevices or holes - is stressed by hot water or water vapour.Halogenated hydrocarbons have thus been proved to be dangerous only when metallic parts are exposed to the condensing solvent zone containing just small amounts of water. In excess of water, no corrosion or cracks could be observed.Although, according to results obtained, risks of corrosion can be kept at a low level, it is recommended to avoid the use of halogenated solvents in case the removal of trapped fluid is limited.
    Notes: Halogenierte Kohlenwasserstoffe finden zur Reinigung metallischer Gegenstände breite Anwendung. Da Lösemittel dieser Art in Anwesenheit von Wasser hydrolysieren, werden ernste Schäden speziell bei Legierungen befürchtet, die für ihre Anfälligkeit für Spannungsrißkorrosion bekannt sind.Mit den vorliegenden Untersuchungen wurde beabsichtigt, das Korrosionsrisiko abzuschätzen, das sich ergibt, wenn halogenierte Kohlenwasserstoffe als Reinigungsmittel für metallische Oberflächen verwendet werden und Flüssigkeitsreste, die in engen Spalten oder Löchern gefangen sind, mit heißem Wasser oder Wasserdampf beaufschlagt werden.Halogenierte Kohlenwasserstoffe haben sich dabei nur dann als gefährlich herausgestellt, wenn die Metalle der Kondensationszone von verdampftem Lösemittel bei Anwesenheit von wenig Wasser ausgesetzt werden. Liegt Wasser im Überschuß vor, konnten keine Korrosion oder Spannungsrisse beobachtet werden.Obgleich jedoch, den Untersuchungsresultaten entsprechend, das Korrosionsrisiko gering gehalten werden kann, wird empfohlen, auf eine Verwendung halogenierter Kohlenwasserstoffe möglichst zu verzichten, wenn die Möglichkeiten einer vollständigen Entfernung des Lösemittels beschränkt sind.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/maco.19820330705
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  • 7
    Electronic Resource
    Electronic Resource
    Arylsulfonylhydrazone und N-Glykoside der 2-Desoxy-D-ribose (1960)
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 11 (1960), S. 90-93 
    Details
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Arylsulfonylhydrazone, Naphthylamide und Toluidide der 2-Desoxy-D-ribose werden dargestellt. Diese sind zur Reinigung der 2-Desoxy-D-ribose weniger geeignet als das bekannte Anilid.
    Additional Material: 1 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/prac.19600110112
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  • 8
    Electronic Resource
    Electronic Resource
    Zur Kenntnis der katalytischen Oxydation des Naphthalins und von Derivaten in der Gasphase (1941)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 54 (1941), S. 22-26 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19410540105
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  • 9
    Electronic Resource
    Electronic Resource
    Über die Ursachen der hohen Lösungsgeschwindigkeit der Phosphorsäure in alkalischen Glühphosphaten (1951)
    Weinheim : Wiley-Blackwell
    Zeitschrift für die chemische Industrie 63 (1951), S. 71-72 
    Details
    ISSN: 0044-8249
    Keywords: Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Die hohe Lösungsgeschwindigkeit der Phosphorsäure in alkalischen Glühphosphaten, z. B. Rhenaniaphosphat, wird wesentlich durch dessen Mischkristallbildung mit Calciumorthosilicat gefördert. Die Umwandlung dieses Mischkristalls, die bei 630° einsetzt, führt zu Calciumnatriumphosphat und damit verringerter Lösungsgeschwindigkeit. Die spezifische Wirkung des Calciumsilicats kann mit seiner bei über 675° beständigen hydraulischen γ-Modifikation in Beziehung gesetzt werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/ange.19510630304
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  • 10
    Electronic Resource
    Electronic Resource
    Electron Transfer in Dinuclear Cobalt Complexes with “Non-innocent” Bridging LigandsPart of this work was presented at the 31st International Conference on Coordination Chemistry, Vancouver (Canada), August 1996. (1997)
    Weinheim : Wiley-Blackwell
    Chemistry - A European Journal 3 (1997), S. 732-743 
    Details
    ISSN: 0947-6539
    Keywords: bridging ligands ; charge transfer ; cobalt ; quinones ; tripodal ligands ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Reaction of tripod cobalt(II) templates [{CH3C(CH2PAr2)3}CoII] with potentially bridging ligands L generates the dinuclear compounds [(tripod)-Co-L-Co(tripod)]2+. With L = oxalate (C2O2-4) a biscobalt(II) complex (1) is formed, while with L = C6H2O2-4, the dianion derived from 2,5-dihydroxy-1,4=benzoquinone (anilic acid), two-electron transfer within the dimetallic unit occurs and a biscobalt(III) charge distribution results (2a), as shown by X-ray structural analyses of 1 and 2a, NMR spectroscopy, and theoretical investigations by the INDO method. Complex 2a exhibits an unusually intense, low-energy absorption in its electronic spectrum; this is explained with a simple MO model. One-electron reduction of 2a generates the corresponding mixed-valence complex, which is highly stabilised through extensive electron delocalisation. Substituents at the 3,6 positions of the bridging ligand (Cl, Br, I, NO2, Me, iPr, Ph; 2b-h) as well as alkyl substitution at the aromatic rings of the tripod ligands (3, 4) influence the optical and electrochemical properties consistent with the proposed model of charge distribution. Formal replacement of one [(tripod)CoIII]3+ moiety by [CH2]2+ leads to the mononuclear complex 6, which is shown to be a typical [(tripod)CoIII=(catecholato)]+ complex. Therefore the substantially different optical and electrochemical properties of the dinuclear complexes with respect to those of 6 result from strong metal-metal interactions mediated by the bridging ligand.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/chem.19970030513
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