Molecular bismuth(III) monocations: structure, bonding, reactivity, and catalysis.

Cationic bismuth(iii) species [BiR2]+ with weakly coordinating counteranions feature two monoanionic ligands R (such as aryls, amides, alcoholates or halides), a vacant bismuth-centred p-orbital, and an occupied bismuth-centred s-orbital. The vacant orbital is available for intra- and intermolecular σ- and π-type bonding interactions and plays a crucial role in redox chemistry. The occupied s-orbital may also show minor contributions to dative bonding and is essential when addressing reversible Bi(iii)/Bi(v) redox shuttling.