revealed. A combined solid-state XRD and NMR investigation of the tris(pentamethylphenyl) silylium borate [(Me5C6)3Si]2[B12Cl12] disclosed the trigonal planar coordination environment of the silicon atom in this silyliumion. NMR investigations indicate for 2,4,6-triisopropylphenyl-substituted silylium and germylium ions the onset of C–H···E+ three-center interactions (E = Si, Ge) between the distant CH
Si–B Functional Group Exchange Reaction Enabled by a Catalytic Amount of BH<sub>3</sub>: Scope, Mechanism, and Application
作者:Jiong Zhang、Rui Wei、Chunping Ren、Liu Leo Liu、Lipeng Wu
DOI:10.1021/jacs.3c05625
日期:2023.7.19
Functional groupexchanges based on single-bond transformation are rare and challenging. In this regard, functional groupexchangereactions of hydrosilanes proved to be more problematic. This is because this exchange requires the cleavage of the C–Si bond, while the Si–H bond is relatively easily activated for hydrosilanes. Herein, we report the first Si–B functional groupexchangereactions of hydrosilanes
The Lewis acidity of several aryl-substituted tetrylium ions was classified experimentally by applying the Gutmann-Beckett method and computationally by calculation Of fluoride ion affinities (FIA) (tetrel elements = Si, Ge). According to these measures, tetrylium ions are significantly more Lewis acidic than boranes, and aryl-substituted silylium borates are among the strongest isolable Lewis acids. A fine-tuning of the Lewis acidity of silylium ions is possible by taking advantage of electronic and/or steric substituent effects.