Chemistry of Octasilacubane

Abstract

Octasilacubane is an intriguing polyhedral polysilane because of its unique electronic properties arising from highly strained Si-Si σ-bonded framework. The first octasilacubane, octakis (t-butyldimethylsilyl) octasilacubane was reported by our group in 1988, as the first example of Platonic solid compounds comprising Group 14 elements other than carbon. We then prepared the alkyl-substituted one (ThexSi)8 (Thex = 1,1,2-trimethylpropyl) in 1992. These octasilacubanes are fairly stable, and various reactions, e.g., halogenation, oxidation, and photoreaction have been reported. Thus, the reaction of (ThexSi)8 with PCl5 leading to dichlorides via skeletal rearrangement, the halogenation with Br 2 or I2 leading to dibromides or diiodides, and the reductive dehalogenation of these dihalides with sodium to regenerate (ThexSi)8. Photo-initiated partial oxidation with DMSO gave monooxaoctasilahomocubane and dioxaoctasilabishomocubane. In this paper, in addition to these reactions, structure, thermal property, photoluminescent property, and UV property of octasilacubanes were summarized.