Uncharged Lewis superacidic silicon complexes—perfluoropinacolato-stabilized systems for homogenous catalysis

Abstract

Lewis superacids are defined as species that exceed the Lewis acidity of SbF5, which was known as the strongest Lewis acid until the isolation of C6H5FAl(OC(CF3)3)3 in 2008. Whereas strong Lewis acids and their prospects in synthesis and catalysis were recognized for a long time, especially uncharged and four-coordinated silanes have been overlooked until recent years. In this contribution, we want to highlight the special features of highly Lewis acidic and Lewis superacidic tetranes. Specifically, we put emphasis on the synthesis, characterization, and catalytic application of silanes and germanes, stabilized by the perfluoropinacolato ligand. Our findings are put into context with previously prepared Lewis superacidic silanes (e.g. bis(catecholato)tetranes and Si(OTf)4 (OTf = trifluoromethanesulfonate).