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  • 1
    Electronic Resource
    Electronic Resource
    Syntheses of Chiral, Intramolecularly Coordinated Aluminum Bromides (2000)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 2000 (2000), S. 153-157 
    Details
    ISSN: 1434-1948
    Keywords: Aluminum ; Ab initio calculations ; Isomers ; Intramolecular donor-acceptor systems ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Three aluminum compounds Ar*AlBr2 (1), Ar*AlBrtBu (2), and Ar*2AlBr (3), incorporating the chiral ligand Ar* = 2-[1-(S)-Me2NCH(Me)]C6H4, have been synthesized by salt metathesis reactions and have been characterized by multinuclear NMR (1H, 13C, and 27Al), mass spectrometry, and elemental analysis. The molecular structure of compound 3 has been determined by a single-crystal X-ray analysis (space group P212121). Alane 2 exists as a temperature-independent equilibrium mixture of two diastereomers in solution (ratio 45:55); results of NOE experiments on 2 are discussed. Only one isomer was found for compound 3 in solution and its dynamic behavior has been investigated by variable-temperature NMR methods; a ΔH of 56.6(4) kJ mol-1 and a ΔS of -0.79(1) J K-1mol-1 were deduced from band-shape analysis of the 1H-NMR signals of the N-bound methyl groups.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 2
    Electronic Resource
    Electronic Resource
    Synthesis and Structural Characterization of Azatitanacyclobutane Derivatives (1998)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1998 (1998), S. 253-256 
    Details
    ISSN: 1434-1948
    Keywords: Titanium ; Vinylidene complexes ; [2+2] Cycloaddition ; Metallacycles ; Azatitanacyclobutanes ; Clathrates ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The titanocene vinylidene intermediate [Cp*2Ti=C=CH2] (9) reacted with the carbodiimides R-N=C=N-R [R = p-CH3C6H4 (19a), C6H11 (19b)] to give the N=C-cycloaddition products [Cp*2Ti{-NR-C(=NR)-(C=CH2)-}] [(R = p-CH3C6H4 (20a), C6H11 (20b)]. The X-ray structure of 20a in form of a surprisingly stable n-hexane clathrate is presented. The azatitanacyclobutane [Cp*2Ti{-NPh-C(Ph)(H)-(C=CH2)-}] (22) was formed from the reaction between 9 and benzylidene aniline [PhN=C(Ph)H (21)]. Reactivity studies showed that azatitanacyclobutanes are unreactive upon typical ring-enlargement reactions as observed for other four-membered titanacycles.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of the First [1]Boratitanocenophanes (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 69-73 
    Details
    ISSN: 1434-1948
    Keywords: Boron ; Titanium ; Metallocenophanes ; [1]Boratitanocenophanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: This paper presents two methods for the synthesis of the first [1]boratitanocenophanes. The novel biscyclopentadienylborane [(Me3Si)2NB(C5H5)2], the dilithio salt Li2[(Me3Si)2NB(C5H4)2] (1) of which was characterized by multinuclear NMR methods, was prepared in situ, and served as starting material for several [1]boratitanocenophanes. [Cl2Ti{(C5H4)2BN(SiMe3)2}] (2) was obtained in high yield by a convenient one-pot synthesis starting from 1 and [TiCl3(thf)3], followed by oxidation with PbCl2. The highly reactive [(Me2N)2Ti{(C5H4)2BN(SiMe3)2}] (3) was obtained by the reaction of [(Me3Si)2NB(C5H5)2], prepared in situ, with Ti(NMe2)4and converted into the chloro derivatives [(Me2N)ClTi{(C5H4)2BN(SiMe3)2}] (4) and [Cl2Ti{(C5H4)2BN(SiMe3)2}] (2) by treatment with one or two equivalents of a suitable diaminochloroborane. All [1]boratitanocenophanes were characterized in solution by multinuclear NMR spectroscopy, and in addition the structure of 2 in the crystalline state was determined by a single-crystal X-ray study.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 4
    Electronic Resource
    Electronic Resource
    Synthesis and Structure of [1]Borametallocenophanes of Titanium, Zirconium, and Hafnium (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1899-1904 
    Details
    ISSN: 1434-1948
    Keywords: Boron ; Titanium ; Zirconium ; Hafnium ; Metallocenophanes ; Metallocenophanes ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Various [1]borametallocenophane complexes of all the group IV metals were obtained in high yield by a very efficient multistep, one-pot synthesis. By this method not only the biscyclopentadienyl and diindenyl complexes [{R2NB(η5-C5H4)2}MCl2] (M = Zr, R = Me, SiMe3, 4a, b; M = Hf, R = SiMe3, 5) and [{(Me3Si2)NB(η5-C9H6)2}MCl2] (M = Ti, 6; M = Zr, 7) were obtained, but also complexes with two different η5-coordinated ligands such as [{iPr2NB(η5-C5H4)(η5-C9H6)}MCl2] (M = Zr, 8; M = Hf, 9). Some of compounds 4-9 were chosen to investigate their catalytic properties with respect to Ziegler-Natta-type polymerisation of olefins, and proved to be highly efficient for the preparation of polyethylene.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
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