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  • 1
    ISSN: 1434-1948
    Keywords: Cluster ; Nickel ; Tin ; Bimetallic complexes ; Electrochemistry ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Addition of stannylene [{(SiMe3)2CH}2Sn:] (2) to the unbridged homobimetallic Ni-Ni bond of [{PEt3Ni(η5-Cp)}2] (1) gives the heterobimetallic, tetranuclear compound [{{(SiMe3)2CH}2Sn-Ni(η5-Cp)}2] (3) with a butterfly arrangement and leaves the Ni-Ni bond of 1 intact. Elimination of both PEt3 ligands from the starting material 1 is observed, probably due to steric restraints. Compound 3 is formally related to the hypothetical closo-borane B4H42-. The Ni-Ni bond in 3 is only slightly elongated [2.454(3) Å] when compared to the starting material 1 [2.41(1) Å]. Compound 3 displays a butterfly arrangement with a hinge angle of 62.5°. An alternative route to 3 is by a direct reaction between nickelocene (5) and Lappert's stannylene [{(SiMe3)2CH}2Sn:] in 63% yield. Treating 3 with water results in the cleavage of an Ni-Sn bond and subsequent opening of the cluster cage of 3 to form the trinuclear compound [(η5-Cp)Ni{Sn(CH(SiMe3)2}2OH] (6) having an Sn-OH-Sn bridge. The hydroxy proton in 6 can be exchanged by deuterium within a few minutes, as determined by 1H-NMR spectroscopy, giving the monodeuterio product, [D1]-6. Compound 6 is reactive towards acetonitrile, leading to cleavage of one Ni-Sn bond, elimination of one [{(SiMe3)2CH}2Sn:] unit, and formation of the organotin hydroxo complex [{(SiMe3)2CH}2(OH)Sn-Ni(η5-Cp)(CH3CN)] (7). In this complex, acetonitrile is coordinated to Ni via its σ lone pair, bearing the OH ligand in a terminal bonding mode to tin.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 1999 (1999), S. 491-497 
    ISSN: 1434-1948
    Keywords: Boron ; Diazaboroles ; Hydrides ; Tin ; Heterocycles ; Chemistry ; General Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 1,3-Di-tert-butyl-2,3-dihydro-1H-1,3,2-diazaborole (4a) and 1,3-bis(2,6-dimethylphenyl)-2,3-dihydro-1H-1,3,2-diazaborole (4b) were formed by the reaction of the corresponding 2-bromo or 2-iodo derivatives 1a and 2b with LiAlH4. Treatment of 1a with n-butyllithium afforded 2-n-butyl-1,3-di-tert-butyl-2,3-dihydro-1H-1,3,2-diazaborole (5a), whereas 1,3-di-tert-butyl-2-cyano-2,3-dihydro-1H-1,3,2-diazaborole (3a) was converted into the 2-tert-butyl derivative 6a or the 2-ethynyl-1,3,2-diazaborole 7a by means of tert-butyllithium or by the ethylenediamine adduct of lithium acetylide. Similarly, 1,3-di-tert-butyl-2-trimethylstannyl-2,3-dihydro-1H-1,3,2-diazaborole (8a) and 1,3-bis(2,6-dimethylphenyl)-2-trimethylstannyl-2,3-dihydro-1H-1,3,2-diazaborole (8b) were accessible from 1a or 2b and trimethylstannyllithium. In the complex 9a the compound 3a serves as an η1 ligand towards the [Cr(CO)5] unit via the cyano group. These novel compounds were characterized by 1H-, 11B-, 13C-, and 119Sn-NMR spectroscopy, as well as by X-ray structure analyses of 4b, 8a, and 9a.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0009-2940
    Keywords: Imidazoles ; Carbenes ; Sulfur Compounds ; Fluorine Compounds ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Imidazole Derivatives, XIXPart XVIII: Ref.[1] .  -  Coordination or reduction? On the Reaction of 1,3-Diisopropyl-4,5-dimethylimidazol-2-ylidene with Sulfur Halides and Sulfur Oxygen Halides Herrn Professor Max Herberhold zum 60. Geburtstag gewidmet.The reaction of 1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene (4, Im) with sulfur halides and sulfur oxygen halides may be described as a coordination (1) or reduction (2) process in respect to the sulfur centre. With SCl2 and SOCl2 the hypervalent sulfur compounds Im · SCl2 (5) and Im · S(O)Cl2 (13) are obtained. The SF2 adduct Im · SF2 (11) is formed on treatment of 5 with AgF. 13 is alkylated by methyl iodide to give the Im · S(Me)OCl2 cation (15). Surprisingly, reduction of the sulfur centre (2) occurs on treatment of 4 with SF4 to form the ImF+SF3- salt 18 containing the new SF3 anion. As expected, the same type of reaction occurs with the sulfuryl halides SO2ClF and SO2F2 to give the fluorosulfites ImCl+-SO2F- (21) and ImF+SO2F- (23). The X-ray structures of 5, 13 and 23 are reported.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0009-2940
    Keywords: Boron ; Diazaboroles ; Carbenes ; Heterocycles ; Imidazoles ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 2-Bromo-2,3-dihydro-1H-1,3,2-diazaboroles (3a-c) were synthesized by cyclocondensation of dilithiated 1,4-diazabutadienes (5a-c) with boron tribromide in hexane. 3a was also obtained by sodium amalgam reduction was conducted in ether solvents, diboroxane (2) resulted as the main product. Compound 3a and 1,3-dialkyl-4,5-dimethylimidazol2-ylidenes (6a, b) underwent halide displacement to afford the borolylimidazolium salts 7a, b. Compounds 2, 3a-c, and 7a, b were characterized by elemental analyses and spectroscopic methods (1H, 11B, 13C NMR; Ir; MS). The molecular structures of 2 and 7a were established by single-crystal X-ray diffraction analyses.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0009-2940
    Keywords: Imidazoles ; Pentacarbonyl metal complexes ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Imidazole Derivatives, XI. - (C8H14N2)M(CO)5 (M = Mo, W) - Terminal Coordination of an Olefin in Pentacarbonyl Metal ComplexesHerrn Professor Reinhard Schmutzler zum 60. Geburtstag gewidmet.The 2-methylenimidazoline complexes (C8H14N2)M(CO)5 (M = Mo, W; 6) are obtained from M(CO)6 and 1,3,4,5-tetramethyl-2-methyleneimidazoline (5). Spectroscopic data reveal the strong donor character of the ylidic ligand in 6. The end-on coordination mode of the olefin is demonstrated by an X-ray structure analysis of 6a.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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