STEPWISE SYNTHESIS OF SiOSiN-RINGS AND CAGES |
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Authors: | Susanne Kliem Uwe Klingebiel |
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Institution: | University Goettingen , Goettingen, Germany |
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Abstract: | Aminosilanols can be stabilized kinetically, e.g. (Me 3 C) 2 Si(OH)NH 2 , which crystallizes in ladder like chains via H-bridges. Its lithium salt was characterized as tetramer, forming a Li─O cubane, while the sodium and potassium salts are hexagonal prisms. The aminosilanol reacts with halosilanes to give amino-1,3-siloxanes. Lithium salts of amino-1,3-disiloxanes were isolated as amido-1,3-siloxanes or silylamino-silanolates. This includes a 1,3-silylgroup migration from the oxygen to nitrogen atom. Lithium salts of fluorofunctional amino-1,3-disiloxanes were characterized by X-ray. They crystallize as monomers or dimers and have unusual types of structures. LiF-elimination from such lithium salts leads to the formation of four- or eight-membered (SiNSiO)-ring systems. The chemical behavior of aminosilanols, the formation of structural isomers and of different ring systems are proved by experiments, crystal structures, and quantum chemical calculations. |
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Keywords: | Aminosiloxanes lithium salts (SiOSiN)-rings |
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