Trifluoromethylbismuth dications: pronounced parallel substrate activation, Lewis superacidity, and catalytic application.

Understanding and exploiting the multiple facets of Lewis acidity represents a topical challenge in molecular chemistry. Here we present the synthesis of well-defined bismuth compounds bearing the electron-withdrawing CF3 group as a key structural feature. Most importantly, a range of dicationic species [Bi(CF3)(L) n ]2+ could be isolated and characterized, the charge being balanced by different weakly coordinating anions (L = neutral ligand). The dicationic species are highly Lewis acidic (culminating in Lewis superacidity) and show the unusual ability to strongly activate two soft Lewis bases in parallel. The strong Lewis acidity was translated into a remarkable catalytic activity in the reduction of phosphane oxides.