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  • 1995-1999  (5)
  • 1985-1989
  • 1960-1964  (3)
  • 1950-1954
  • 1900-1904
  • 1810-1819
  • 1996  (5)
  • 1963  (3)
  • Titanium
  • 1
    Electronic Resource
    Electronic Resource
    New [Ti(η5-C5H5)Cl2(OR)] complexes. Crystal and molecular structure of η5-Cyclopentadienyl(cyclohexoxy)titanium(IV) dichloride (1996)
    Springer
    Monatshefte für Chemie 127 (1996), S. 1137-1143 
    Details
    ISSN: 1434-4475
    Keywords: Titanium ; Cyclopentadienyl ; Akloxytitanium complexes ; X-ray analysis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Durch Umsetzung von [Ti(η5-C5H5)Cl3] mit dem geeigneten Alkohol wurde eine Reihe von neuen Verbindungen der Formel [Ti(η5-C5H5)(OR)] (R=C6H11 (cyclohexyl,1), CH2CH(CH3)2 (2), CH(C2H5)2 (3) und CH2C6H5 (4)) erhalten. Alle Komplexe wurden elementaranalytisch sowie IR- und1H-NMR-spektroskopisch charakterisiert. Die Struktur von1 wurde röntgenographisch bestimmt; Kristalldaten: triklin,a=11.334(2),b=13.590(2),c=12.237(2) Å, α=113.501(5), β=118.182(5), γ=101.993(6),V=1328.2(4) Å3,T=298K, Raumgruppe P1,Z=4, zwei kristallographisch unabhängige Moleküle in der Elementarzelle; abschließendeR-Werte:R=0.0583 undR w=0.0632. Verbindung1 zeigt überraschend kurze Ti-Cl- und Ti-O-Abstände; dies deutet auf eine starke π-Elektronendonorwirkung des Chlorid- und vor allem des Alkoxidliganden hin. Der Ti-O-C-Bindungswinkel ist ungewöhnlich groß.
    Notes: Summary A series of new compounds with molecular formula [Ti(η5-C5H5)Cl2(OR)] (R=C6H11 (cyclohexyl,1), CH2CH(CH3)2 (2), CH(C2H5)2 (3), and CH2C6H5 (4)) has been obtained by the reaction of [Ti(η5-C5H5)Cl3] with the appropriate alcohol. All complexes were characterized by elemental analysis and by IR and1H NMR spectroscopy. The structure of1 was determined by X-ray diffraction studies; crystal data: triclinic,a=11.334(2),b=13.590(2),c=12.237(2) Å, α=113.501(5), β=118.182(5), γ=101.993(6),V=1328.2(4) Å3,T=298K, space P1,Z=4, two crystallographically independent molecules in the unit cell. FinalR andR w values are 0.0583 and 0.0632, respectively. Compound1 exhibits surprisingly short Ti-Cl and Ti-O distances, suggesting strong π donation by the chloride and in particular by the alkoxide ligand. The Ti-O-C angle is unusually large.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00844688
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  • 2
    Electronic Resource
    Electronic Resource
    The Mechanism of the Double Bond Cleavage in the Titanium Zeolite-catalyzed Oxidation of α-Methylstyrene by Hydrogen Peroxide: the β-Hydroperoxy Alcohol as Intermediate (1996)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 129 (1996), S. 1453-1455 
    Details
    ISSN: 0009-2940
    Keywords: Zeolites ; Titanium ; Epoxidation ; Double bond cleavage ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: It is unequivocally shown that acetophenone, an oxidation product in the titanium zeolite-catalyzed oxidation of α-methylstyrene, derives from 2-hydroperoxy-2-phenyl-1-propanol as intermediate, which was detected and isolated in this reaction for the first time.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19961291209
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  • 3
    Electronic Resource
    Electronic Resource
    Pyramidal slip in electron beam heated deformed Titanium (1996)
    Springer
    Interface science 3 (1996), S. 195-201 
    Details
    ISSN: 1573-2746
    Keywords: slip transmission ; grain boundaries ; residual dislocations ; image simulation ; Titanium
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract The incidence of perfect glide dislocations, moving on parallel pyramidal slip bands on a particular grain boundary of deformed Titanium is studied by means of Transmission Electron Microscopy. Static experiments, performed by using the electron beam as a heating source, proved that slip propagation across the interface is possible when the angle of intersections between the activated slip planes of the incoming and the outgoing dislocations with the boundary plane is minimised. Additionally, the Burgers vector of the residual dislocations left in the boundary after slip transmission occurred should also be minimised. Due to their very small Burgers vector, residual dislocations are visualised with satisfactory results by an image simulation method.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00191046
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  • 4
    Electronic Resource
    Electronic Resource
    Synthesis, characterization, and structures of New Titanocene Isoselenocyanato Complexes (1996)
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 622 (1996), S. 1387-1391 
    Details
    ISSN: 0044-2313
    Keywords: Titanium ; Metallocene ; Isoselenocyanate ; Crystal Structure ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Darstellung, Charakterisierung und Strukturen von neuen Titanocen-isoselenocyanat KomplexenDie Komplexe [Ti(η5-C5H4R)2(NCSe)2] [R = Me (1), SiMe3 (2) oder SiEt3 (3)] wurden durch Umsetzung der entsprechenden Dichloride mit KSeCN dargestellt; der sauerstoffverbrückte Komplex [Ti(η5-C5H4R)2(NCSe)]2O (4) entsand durch Luftoxidation von (1). Alle Komplexe wurden elementaranalytisch sowie IR-, 1H-NMR- und massenspektroskopisch charakterisiert. Die Röntgenstrukturanalysen von (1) und (4) bestätigen die IR-Ergebnisse, daß diese Komplexe N-gebundene Selenocyanat-liganden enthalten. Die Geometrie um Titan ist pseudotetraedrisch. Die Ketten N—C—Se sind linear mit normalen N—C und C—Se Bindungsabständen. Das Dimer enthält eine annähernd lineare Ti—O—Ti Brücke (Bindungswinkel 173,4º) mit einem Ti—O-Abstand von 1,838 Å. Die Strukturergebnisse werden mit denen analoger Verbindungen verglichen.
    Notes: The complexes [Ti(η5-C5H4R)2(NCSe)2] [R = Me (1), SiMe3 (2), or SiEt3 (3)] were prepared from the corresponding dichlorides with KSeCN in acetone; the oxygen-bridged complex [Ti(η5-C5H4Me)2(NCSe)]2O (4) was formed by air oxidation of (1). All complexes were characterized by elemental microanalysis and by IR, 1H NMR, and mass spectroscopies. An X-ray analysis of (1) and (4) confirms the results of IR studies that these complexes contain N-bonded selenocyanate ligands. In molecules (1) and (4) there is a pseudotetrahedral arrangement about each titanium. The N—C—Se chains are linear with normal N—C and C—Se bond distances. The dimer (4) contains an approximately linear Ti—O—Ti bridge (angle 173.4º) with a Ti—O bond distance of 1.838 Å. The structural results are compared with those in related compounds.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/zaac.19966220818
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  • 5
    Electronic Resource
    Electronic Resource
    New Developments in the Chemistry of Low-Valent TitaniumDedicated to Professor Henri B. Kagan on the occasion of his 65th birthday (1996)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 35 (1996), S. 2442-2469 
    Details
    ISSN: 0570-0833
    Keywords: alkenes ; carbonyl compounds ; heterocycles ; McMurry reactions ; titanium compounds ; Alkenes ; Carbonyl compounds ; Heterocycles ; McMurry reaction ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Among the applications of low-valent titanium in organic synthesis, the reductive coupling of carbonyl compounds to produce alkenes (the McMurry reaction) is particularly prominent. Discovered at the beginning of the 1970s, it has been developed and tested repeatedly, for example in numerous syntheses of natural products. This alkene synthesis has become a standard reaction in the repertoire of preparative chemists. However, the possibilities of low-valent titanium are by no means limited to this process: the last few years have brought some spectacular applications of the conventional McMurry reaction (for example the synthesis of taxol) along with a considerable extension of the scope of reductive carbonyl couplings. Thus, diverse heterocycles are now accessible following novel and efficient pathways based on intramolecular cross-coupling of functional groups - some of which were hitherto considered to be inert to titanium. The use of this method for the synthesis of indole and pyrrole alkaloids illustrates the new possibilities. At the same time, considerably simplified methods for conducting McMurrytype reactions have been developed. Examples include the particularly convenient “instant” method, the first ketone-amide coupling reactions requiring only catalytic amounts of titanium salts, and the first application of commercially available titanium powder as a coupling agent. Last but not least, the detailed investigation of diverse classical McMurry reagents has afforded a deeper understanding of the nature and mode of action of low-valent titanium. Revision of some of the current conceptions of the process of reductive carbonyl coupling is thus indispensable.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.199624421
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  • 6
    Electronic Resource
    Electronic Resource
    Low-Temperature Polymerization of EthylenePublished on the occasion of the 100th anniversary of the founding of Farbwerke Hoechst on January 11th, 1963 (1963)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 32-41 
    Details
    ISSN: 0570-0833
    Keywords: Polymerization ; Polyethylene ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: A two-component organometallic catalyst of composition CH3TiCl3·CH3AlCl2 effects high-speed polymerization of ethylene in the presence of chlorinated hydrocarbons at low temperatures. The catalyst does not undergo any alteration in the process. In contrast to the Ziegler catalysts, the titanium remains quadrivalent. Olefins of low-molecular-weight and with branched structures are produced. It proved possible to isolate the primary products of the polymerization at -50 to -100°C and to elucidate the mode of their formation from a knowledge of their structures. The findings are incompatible with either a cationic or anionic reaction mechanism. A novel type of mechanism is proposed, whereby the catalyst is supposed to have an ionic structure and molecular growth proceeds via π-complex formation of the olefin with the titanium cation. The formation of ethylene/olefin copolymers is also discussed.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196300321
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  • 7
    Electronic Resource
    Electronic Resource
    Cyclooligomerization of Butadiene and Transition Metal π-Complexes (1963)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 105-115 
    Details
    ISSN: 0570-0833
    Keywords: Cyclooligomerization ; Butadiene ; Titanium ; Cyclododecatriene ; Cyclooctadiene ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Advances in the fields of synthesis and reactions of some medium-sized hydrocarbon rings are reported and in connection therewith on novel π-complexes of transition metals. Catalytic syntheses yield 1,5,9-cyclododecatriene, 1,5-cyclooctadiene, and 1,5-cyclodecadiene either from butadiene or from butadiene and ethylene. The reactions proceed very readily.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196301051
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  • 8
    Electronic Resource
    Electronic Resource
    Reactions of Olefins with the Titanium-Carbon BondDedicated to Prof. Dr. Karl Ziegler on the occasion of his 65th birthday (1963)
    Weinheim : Wiley-Blackwell
    Angewandte Chemie International Edition in English 2 (1963), S. 704-714 
    Details
    ISSN: 0570-0833
    Keywords: Titanium ; Alkenes ; Polymerization ; Titanium ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: At low temperatures, ethylene and α-olefins (Δ1-olefins or 1-alkenes) are rapidly converted into oligomrs by the two-component organometallic catalyst CH3TiCl3·CH3AlCl2. To achieve smooth oligomerizations, aromatic or chlorinated hydrocarbons must be used as solvents. Although the activity of the titanium-carbon bond is enhanced by the aluminum component of the catalyst, the aluminum and its methyl group do not participate in the reaction proper; the latter proceeds exclusively at the titanium-carbon bond. The reaction will olefins can be used as an analytical method for the quantitative determination of the titanium-carbon bond in admixture with the organoaluminum component. It is thus possible to follow the reaction leading to formation of the catalyst from titanium tertrachloride, as well as the processes occurring at the titanium-carbon bond during the oligomerization of olefins. All the observations indicate that the catalyst possesses an ionic structure which is determined by the solvent. It is shown that the initial reaction step probably involves formation of a complex between the olefin and the alkyltitanium cation. The reaction scheme proposed is based on organometallic reactions which are characterized by carbanion and hydride transfers within the olefin-cation complex. This mechanism, which is unusual for Ziegler catalysts, is due to the predominance of hydride transfers.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/anie.196307041
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