No neutral silicon Lewis super acids are known to date. We report on the synthesis of bis(perchlorocatecholato)silane and verify its Lewis super acidity by computation (DLPNO-CCSD(T)) and experiment (fluoride abstraction from SbF ). The exceptional affinity towards donors is further demonstrated by, for example, the characterization of an unprecedented SiO F dianion and applied in the first hydrodefluorination reaction catalyzed by a neutral silicon Lewis acid. Given the strength and convenient access to this new Lewis acid, versatile applications might be foreseen.

Quinones are mild oxidants, the redox potentials of which can be increasedb ys upramolecular interactions. Whereas this goal has been achieved by hydrogen bondingo rm olecular encapsulation, aL ewis acid-binding strategyf or redox amplificationo fq uinones is unexplored. Herein,t he redox chemistry of silicon tris(perchloro)dioxolene 1 was studied, whichi st he formal adduct of orthoperchloroquinone Q Cl with the Lewiss uperacid bis(perchlorocatecholato)silane 2.B yi solatingt he anionic monoradical 1C À À ,t he redox-series of ac entury-old class of compounds was completed. Cyclic voltammetry measurements revealed that the redox potentiali n1 was shifted by more than 1V into the anodic direction compared to Q Cl ,r eaching that of "magic blue" or NO + .I ta llowed oxidation of challenging substrates such as aromatic hydrocarbons and couldb ea pplieda sa ne fficient redox catalyst. Remarkably,t his powerful reagent formed in situ by combining the twoc ommercially available precursors SiI 4 and Q Cl .

The reaction of ortho-quinones with silicon tetraiodide leads to neutral silicon trisdioxolenes in high yield, delivering the unknown oxidized form of triscatecholatosilicate dianions and the first example of open-shell semiquinonates connected via as ingle non-metal center.S ilicon tris(perchloro)dioxolene is as table diradical with at riplet ground state,a s supported by X-raydiffraction;IR, resonance Raman, UV/Vis, and (VT)EPR spectroscopy; and Kohn-Sham broken-symmetry computations.P reliminary results suggest that the preferred magnetic ground state can be altered through variation of the substituents.

Anionic hypercoordinated silicates with weak donors were proposed as key intermediates in numerous silicon‐based reactions. However, their short‐lived nature rendered even spectroscopic observations highly challenging. Here, we characterize hypercoordinated silicon anions, including the first bromido‐, iodido‐, formato‐, acetato‐, triflato‐ and sulfato‐silicates. This is enabled by a new, donor‐free polymeric form of Lewis superacidic bis(perchlorocatecholato)silane 1. Spectroscopic, structural, and computational insights allow a reassessment of Gutmann's empirical rules for the role of silicon hypercoordination in synthesis and catalysis. The electronic perturbations of 1 exerted on the bound anions indicate pronounced substrate activation.

Bisher sind noch keine neutralen Silicium-Lewis-Supersäuren bekannt. Wirberichtenhier über die Synthese des Bis(perchlorocatecholato)silans und bestätigen dessen Lewis-Superaziditätd urchB erechnungen (DLPNO-CCSD(T)) und Experimente (Fluoridabstraktion von SbF 6 À