Facile access to stable silylium ions stabilized by n-heterocyclic imines

Novel silylium ions with N-heterocyclic imines were successfully synthesized. The reaction of trimethylsilyl imidazolin-2-imine Me₃ SiNIPr (NIPr = bis(2,6-diisopropylphenyl)-imidazolin-2-imino) with B(C₆ F₅ )3 leads to dimeric imino-substituted silylium ions through a methyl group abstraction on the silicon atom. Meanwhile, the intermolecular imino-coordinated silylium ion is formed by using the less sterically crowded imine Me₃ SiNItBu (NItBu = bis(tert-butyl)-imidazolin-2-imino). Furthermore, the treatment of dimethylchlorosilane Me₂ (Cl)SiNIPr with AgOTf affords the contact ion pair Me₂ (OTf)SiNIPr by substitution of the chloride. A novel complex with the formula [Me₂ (DMAP)SiNIPr][OTf] was prepared by coordination with 4-dimethylamino-pyridine (DMAP). In the solid state, the DMAP adduct [Me₂ (DMAP)SiNIPr][OTf] contains a distinct [Me2 (DMAP)SiNIPr]⁺ moiety.