Tridentate Lewis Acids: Boron-, Silicon- and Gallium-Functionalised Tris(dimethylsilyl)methanes

• Published in: European journal of inorganic chemistry 2016-03, Vol.2016 (8), p.1257-1266
• Main Authors: Weisheim, Eugen, Schwartzen, Anna, Kuhlmann, Lisa, Neumann, Beate, Stammler, Hans-Georg, Mitzel, Norbert W.
• Format: Article
• Language: English
• Subjects: Chlorine; Chlorosilanes; Diffraction; Fluorination; Hydroboration; Hydrosilylation; Lewis acid; Lewis acids; Mass spectrometry; Metalation; NMR spectroscopy; Scaffolds; Silanes; X-rays
• ISSN: 1434-1948; 1099-0682
• DOI: 10.1002/ejic.201501432

Flexible tridentate Lewis acids based on new trisilylmethane scaffolds with three ethynyl groups {Me3SiC[Si(Me)2C≡C–H]3} and three vinyl groups {Me3SiC[Si(Me)2CH=CH2]3}, respectively, have been synthesised and functionalised by metallation with gallium organyls to yield Me3SiC[Si(Me)2C≡C–GaR2]3 (R = Me, Et). Hydrometallation of the trisilylmethane frameworks with HB(C6F5)2 and various chlorosilanes afforded flexible poly‐Lewis acids equipped with B(C6F5)2, SiCl3, SiMeCl2 and SiMe2Cl substituents. The reaction of these silicon‐containing tridentate Lewis acids with SbF3 led to fluorine‐substituted poly‐Lewis acids of the type Me3SiC[Si(Me)2CH2CH2SiMe3–nFn]3 (n = 1–3). All the compounds were characterised by multinuclear NMR spectroscopy, mass spectrometry, elemental analyses and some by X‐ray diffraction. New tridentate Lewis acids based on tris(dimethylsilyl)trimethylsilylmethane scaffolds equipped with ethynyl and vinyl groups have been synthesised. They were functionalised with GaMe2 and GaEt2 groups by alkane elimination, with B(C6F5)2 and SiClnMe3–n groups by hydrometallation reactions and with SiFnMe3–n groups by substitution of the chlorine atoms by fluorine.