The structures of neutral and anionic hydrogen-terminated oligomers (H-Sin-H: n = 2, 4, 6, 8) and silicon six-membered rings (c-Si 6) have been investigated using quantum-chemical methods to find stable planar polysilicon chains and aromatic silicon six-membered rings. Among 18 calculated molecules, planar equilibrium structures have been obtained for seven anionic chains (Si2H22-, Si 4H22-, Si4H2 4-, Si6H24-, Si6H 26-, Si8H24-, Si 8H26-) and three anionic six-membered rings (c-Si62-, c-Si64-, c-Si 66-). The number of π electrons formally accommodated in the out-of-plane π orbitals is the same as the number of silicon atoms and is independent of the number of doped electrons. An anionic six-membered ring, c-Si62-, shows a large negative value of nucleus-independent chemical shift (NICS), which indicates that c-Si 62- is an aromatic molecule.
ASJC Scopus subject areas
- Physical and Theoretical Chemistry
- Organic Chemistry
- Inorganic Chemistry