Theoretical proposal of planar silicon oligomer and silicon benzene

This paper proposes theoretically a new silicon π system where π electrons delocalize on sp2-hybridized silicon backbone similar to carbon π systems, based on a careful insight into the difference in character between the carbon 2p and silicon 3p orbitals. We found planar and acyclic silicon oligomers and D6h silicon benzene as equilibrium structures. The D6h silicon benzene shows a large negative value of nucleus-independent chemical shift, which indicates that it is an aromatic molecule.