Efficient Synthesis of a NHC-Coordinated Trisilacyclopropylidene and Its Coordination Behavior

With a co-reduction procedure using 2 equivalents Mes₂ SiCl₂ and 1 equivalent NHC^iPr2Me2 →SiCl₄ an NHC-adduct of a trisilacyclopropylidene (SiMes₂ )₂ SiNHC^iPr2Me2 1 was synthesized. Addition of NHC^Me4 to 1 results in quantitative carbene exchange under release of NHC^iPr2Me2 to yield (SiMes₂ )₂ SiNHC^Me4 2. Both NHC-coordinated trisilacyclopropylidenes coordinate to BH₃ . In reaction of 1 with SiMe₃ N₃ a NHC-coordinated trisilane with an exocyclic Si=N double bond is formed. With diphenylacetylene 1 undergoes a ring expansion at room temperature to afford a five-membered ring compound with an NHC-coordinated silylene functionality.