Polyorganosilicon compounds in strained carbocyclic systems

Organosilicon chemistry has been highlighted by the successful construction and thorough characterization of strain carbocyclic systems: 1) silabenzene, silafulvene, and polycyclic polysilane via a silylcarbene rearrangement to silene, 2) a ring-expansion reaction of disilacyclobutene with exo-methylene, and 3) cyclic polysilanes containing unsaturated carbon systems, such as acetylene, allene, and fullerene. Some of these numerous compounds, which are now available, are fully substituted with bulky ligands. These compounds permit examinations of: 1) the variation in the physical and chemical properties of a system with polysilane, and 2) how the systems are related thermally and photochemically with carbon analogues. Some cyclic polysilanes may constitute a stepping stone on the way to super-molecules.