Labile Base‐Stabilized Silyliumylidene Ions. Non‐Metallic Species Capable of Activating Multiple Small Molecules

Several base‐stabilized silyliumylidene ions ( 2 and 3 ) with different ligands were synthesized. Their behaviour appeared strongly dependent on the nature of ligand. Indeed, in contrast to the poorly reactive silyliumylidene ions 3   c,d stabilized by strongly donating ligands (DMAP, NHC), the silylene‐ and sulfide‐supported one ( 2‐H and 3   a ) exhibits higher reactivity toward various small molecules. Furthermore, their capability to successively activate multiple small molecules was clearly demonstrated by processes involving successive reactions with silane/formamide, CO 2 and H 2 . Moreover, HBPin adduct of 3   a ( 8‐C ) catalyzes the hydroboration of pyridine. Of particular interest, silylene‐supported silyliumylidene complex 2‐H is one of the rare species able to activate two H 2 molecules.