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  • 1,4-Diborinanes, trimethylsilyl-substituted, isomers of  (1)
  • 119Sn CP/MAS NMR  (1)
  • B(C6F5)3 addition  (1)
  • 1
    Electronic Resource
    Electronic Resource
    Trimethylsilylierte 1,4-Diborinane und 1,3-Diborolane - Bildung, Isomeren-Trennung und Charakterisierung (1994)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 127 (1994), S. 813-820 
    Details
    ISSN: 0009-2940
    Keywords: Hydroboration of 1-alkinylsilanes ; Ethyldiboranes(6) ; Alkyl substituent exchanges ; BH-borane-catalysed ; 1,4-Diborinanes, trimethylsilyl-substituted, isomers of ; Lewisbase - 1,4-Diborinanes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Trimethylsilylated 1,4-Diborinanes and 1,3-Diborolanes - Formation, Isomer Separation, and CharacterisationMe3SiC≡CH (A) reacts with excess (Et2BH)2 via the compounds 1, 1′ and 2, 2′ to yield a mixture of four regio- and stereoisomeric 1,4-diethyl-2,5(6)-bis(trimethylsilyl)-1,4-diborinanes (3a-d) and minor amounts of 1,3-diethyl-2-methyltrans-2,5-bis(trimethylsilyl)-1,3-diborolane (4a). The 2,5-ee-(Me3Si)2 compound 3d is isolated as the adduct 3d(Pic)2 (X-ray structure analysis), from which pure 3d is obtained with Et2O-BF3. 3d and Me3P form equilibria of the 1:1 and 1:2 addition compounds 3d(Me3P)n (n = 1,2) at room temperature. Me3SiC≡CMe (B) reacts with (Et2BH)2 via 5 to give 6-10, and Me3SiC≡CSiMe3 (C) reacts with (Et2BH)2 to form the ring compounds 12 and 13 via the presumably threo/erythro mixture of 11a and b.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/cber.19941270504
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Group 5 Metal Complexes with Cyclooctatetraene: Formation and Characterization of (Butadiene)(cyclooctatetraene)(cyclopentadienyl)tantalum Systems (1999)
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 1461-1466 
    Details
    ISSN: 1434-1948
    Keywords: Diene complexes ; η3-Cyclooctatetraene metal complex ; B(C6F5)3 addition ; Tantalum ; Bicyclo[5.1.0]octadienyl metal complex ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The [(η4-diene)(η5-RCp)TaCl2] complexes 6a-e (diene = butadiene, isoprene or 2,3-dimethylbutadiene; RCp = pentamethylcyclopentadienyl, methylcyclopentadienyl or cyclopentadienyl) react with cyclooctatetraene dianion (employed as [(cot)Li2]) to yield the (η4-diene)(η3-cyclooctatetraene)(η5-RCp)tantalum complexes 7. The η3-cot coordination was confirmed by an X-ray crystal structure analysis of the compound [(supine-s-cis-η4-C4H6)(η3-cot)(η5-Cp*)Ta] 7a. In solution, the cot ligand of all the complexes 7 is fluxional. Two isomers [supine and proneorientation of the (diene)CpTa subunit] were found for the (η4-butadiene)(η3-cot)CpTa system (7e/7e′ = 95:5). Complex 7e cleanly adds the organometallic Lewis acid B(C6F5)3 to yield the betaine system [(η4-C4H6){C8H8B(C6F5)3}Cp*Ta] 8, which contains a substituted bicyclo[5.1.0]octadienyl ligand.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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    Paper (German National Licenses)
  • 3
    Electronic Resource
    Electronic Resource
    η5-Cyclopentadienyl derivatives of tin(II) studied by two-dimensional multinuclear magnetic resonance in solution and by 13C and 119Sn CP/MAS NMR in the solid state (1992)
    Chichester : Wiley-Blackwell
    Organic Magnetic Resonance 30 (1992), S. 964-968 
    Details
    ISSN: 0749-1581
    Keywords: Determination of coupling signs ; Multinuclear two-dimensional NMR ; Pseudo-triple-resonance experiments ; Solid-state ; 119Sn CP/MAS NMR ; Cyclopentadienyltin(II) compounds ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Absolute coupling signs of 1J(119Sn, 13C) (〈O) and 2J(119Sn, 1H) (〈O) in (n5-C5H5)2Sn (1) and 1J(119Sn, 13C) (〈O)2J(119Sn, 13C) (〈O) and 3J(119Sn, 1H) (〉O) in (n5-C5Me5)2Sn (2) were determined using advanced direct and indirect two-dimensional methods. These are based on Ψ-BIRD techniques and z-filtering, leading to pseudotriple-resonance experiments of the type 1H{119Sn(13C)} and 13C{1H(119Sn)}, respectively. A mixed n5-cyclopentadienyltin(II) amide was prepared and characterized by 1H, 13C, 29Si and 119Sn NMR in solution in the presence of its symmetrical redistribution products 1 and [(Me3Si)2N]2Sn. Solid-state 119Sn CP/MAS NMR spectra of 1 shows the presence of two tin sites (in accord with the x-ray analysis) with a 62.2 ppm difference in 119Sn chemical shifts, the mean value being in close agreement with the solution-state δ119Sn value. The symmetries of the shielding tensor for the two tin sites are different and there appears to be a correlation between this property and the ring centroid - Sn - ring centroid angle α. 13C CP/MAS NMR proved insensitive to the structural differences between the two types of molecules of 1 in the unit cell.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mrc.1260301010
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    Paper (German National Licenses)
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