Siliciumtetrakis(trifluormethansulfonat): Ein einfaches, neutrales Silan als weiche und harte Lewis‐Supersäure

Bis(perfluoropinacolato)silane: A Neutral Silane Lewis Superacid Activates Si-F Bonds

Despite the earth abundance and easy availability of silicon, only few examples of isolable neutral silicon centered Lewis superacids are precedent in the literature. To approach the general drawbacks of limited solubility and unselective deactivation pathways, we introduce a Lewis superacid, based on perfluorinated pinacol substituents. The compound is easily synthesized on a gram‐scale as the corresponding acetonitrile mono‐adduct 1⋅(MeCN) and was fully characterized, including single crystal X‐ray diffraction analysis (SC‐XRD) and state‐of‐the‐art computations. Lewis acidity investigations by the Gutmann‐Beckett method and fluoride abstraction experiments indicate a Lewis superacidic nature. The challenging Si−F bond activation of Et₃SiF is realized and promising catalytic properties are demonstrated, consolidating the potential applicability of silicon centered Lewis acids in synthetic catalysis.

Geometrically Constrained Cationic Low-Coordinate Tetrylenes: Highly Lewis Acidic σ-Donor Ligands in Catalytic Systems

A novel non‐innocent ligand class, namely cationic single‐centre ambiphiles, is reported in the phosphine‐functionalised cationic tetrylene Ni⁰ complexes, [^PhRDippENi(PPh₃)₃]⁺ (4 a/b (Ge) and 5 (Sn); ^PhRDipp={[Ph₂PCH₂SiR₂](Dipp)N}⁻; R=Ph, ⁱPr; Dipp=2,6‐ⁱPr₂C₆H₃). The inherent electronic nature of low‐coordinate tetryliumylidenes, combined with the geometrically constrained [N−E−Ni] bending angle enforced by the chelating phosphine arm in these complexes, leads to strongly electrophilic E^II centres which readily bind nucleophiles, reversibly in the case of NH₃. Further, the Ge^II centre in 4 a/b readily abstracts the fluoride ion from [SbF₆]⁻ to form the fluoro‐germylene complex ^PhRDippGe(F)Ni(PPh₃)₃9, despite this Ge^II centre simultaneously being a σ‐donating ligand towards Ni⁰. Alongside the observed catalytic ability of 4 and 5 in the hydrosilylation of alkynes and alkenes, this forms an exciting introduction to a multi‐talented ligand class in cationic single‐centre ambiphiles.