Tuning the Lewis Acidity of Neutral Silanes Using Perfluorinated Aryl- and Alkoxy Substituents |
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| Authors: | Florian S Tschernuth Lukas Bichlmaier Sebastian Stigler Prof Dr Shigeyoshi Inoue |
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| Institution: | TUM School of Natural Sciences, Department of Chemistry, Wacker-Institute of Silicon Chemistry, and Catalysis Research Center, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany |
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| Abstract: | The emerging field of Lewis acidic silanes demonstrates the versability of molecular silicon compounds for catalytic applications. Nevertheless, when compared to the multifunctional boron Lewis acid B(C6F5)3, silicon derivatives still lack in terms of reactivity. In this regard, we demonstrate the installation of perfluorotolyl groups (TolF) on neutral silicon atoms to obtain the respective tetra- and trisubstituted silanes Si(TolF)4 and HSi(TolF)3. These compounds were fully characterized including SC-XRD analysis but unexpectedly showed no significant Lewis acidity. By using strongly electron-withdrawing perfluorocresolato groups (OTolF) the tetrasubstituted silane Si(OTolF)4 was obtained, bearing an 8 % increased Δδ(31P) shift when applying the Gutmann-Beckett method, compared to literature-known Si(OPhF)4. Ultimately the heteroleptic Si(PhF)2pinF was successfully synthesized and fully characterized including SC-XRD analysis, introducing a highly Lewis acidic silicon atom holding two silicon-carbon bonds. |
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| Keywords: | Childs method Gutmann-Beckett method Lewis acids perfluorotolyl ligands silanes |
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