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  • Titill er á ensku Synthesis, analysis and reactions of novel silaorganics
  • Febrúar 2013
  • Útdráttur er á ensku

    We wanted to investigate further the alcoholysis of Cp*Ti(µ-O3)[(tBu)Si–CH2]3, an adamantane complex, previously shown to form a dimeric structure upon reaction with MeOH. Samples were prepared to compare the rate of reaction at different temperatures and with or without exposure to light. Although the results were only partly conclusive, temperature appears to have a mild effect on the reaction rate. Light exposure turned out to be a deciding factor in the outcome of these reactions.
    Analogous samples containing Cp*Ti(µ-O3)[(tBu)Si–CH2]3 and one of three phenols (PhOH, p-tBuPhOH and p-NO2PhOH) were prepared. These indicate that unsubstituted phenol gives the fastest reaction rate. The products from those reactions, however, are unlikely to be dimeric as evidence of Cp* coordinated to the metal centre can still be found.
    A synthetic route was sought from 1,3,5-trisilacyclohexane to a suitable precursor for the synthesis of a kinetically stabilized 1,3,5-trisilabenzene. Several novel substituted 1,3,5-trisilacyclohexanes were synthesized and characterized by NMR and X-ray crystallographic techniques. This research culminated in the successful synthesis of 1,3,5-trichloro-1,3,5-tris(Dipp)-1,3,5-trisilacyclohexane (Dipp = 2,6-di(isopropyl)phenyl), which we believe is a promising precursor to 1,3,5-trisilabenzene.
    Alkali metal salts of transition metal complex anions were synthesized and reacted with 1-halo-1-silacyclohexane (halo = chloro, bromo) in the hope of obtaining a series of transition metal complexes bearing Cp and CO ligands as well as a silacyclohexane moiety. Despite the fact that a reaction occurs between these alkali metal salts and the carbosilane, isolation and unequivocal characterization of the products has not been achieved.
    We planned to synthesize the adamantane complex Cp*Ti(µ-O3)[DisSi–O]3 by the reaction of [DisSi(OH)–O]3 (Dis = –CH(SiMe3)2) with Cp*TiCl3. However, the reaction did not yield the expected product but rather a large tricyclic compound, [Cp*Ti–O–Si((Me3Si)2CH)–O]2[(μ-O2)[Si((Me3Si2)CH)(OH)]]2. After repeated trials at the synthesis we reached a yield of 46% of the pure product.
    Finally we describe the temperature calibration of a Bruker NMR probe head specially adapted to DNMR experiments at very low temperature in connection with conformational studies of sila- and germaorganics.

  • 5.2.2013

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