Octakis(1,1,2‐trimethylpropyl)octasilacubane: Synthesis, Molecular Structure, and Unusual Properties

The thermodynamically and kinetically stable peralkyloctasilacubane 1 is formed in the reaction of SiCl3 (R = CMe2CHMe2) with Na. The orange-red compound is soluble in hydrocarbons and was characterized by spectroscopy and X-ray crystallography. Both its long-wavelength electronic transition in the UV/VIS spectrum at λ ≈ 500 nm and its low oxidation potential found by cyclic voltammetry at 0.43 V—unusual values for cy-clopolysilanes—are traced back to the highly strained Si8 framework.