Reaction of the (Pentamethylcyclopentadienyl)silicon(II) Cation with a Sterically Encumbered β-Diketiminato Anion: Unexpected Formation of a Tricyclic Silicon(IV) Compound

Reaction of the Cp*Si+ cation with the β-diketiminato anion [HC(CMeNAryl)2]− (Aryl = 2,6-iPr2C6H3) did not lead to the expected silicon(II) compound Cp*[HC(CMeNAryl)2]Si (3) but to the constitutional isomer 7 containing a silicon(IV) center. Calculations were performed for 3, for the conformational isomer 3* containing a η3-Cp* ligand, and for less substituted species.