Boron, carbon, and aluminum supertetrahedral graphane analogues

The electronic and spatial structures of carbon, boron, and aluminum supertetrahedrane models of graphane have been studied by means of density functional theory methods in the supermolecular approximation (B3LYP/6-311G(df,2p)) and with imposing periodic boundary conditions (PBEPBE/6-311G (d,p), HSEH1PBE/6-311G (d,p)). Calculations predict that pure boron and aluminum structures are narrow-gap semiconductors. For supertetrahedral carbon graphane, calculations predict properties intermediate between the semiconductor and insulator properties. All bonds in the carbon system are two-center two-electron (2N-2D mu), while for the boron system, intratetrahedrane bonds are three-center two-electron (3N-2D mu), and intertetrahedrane bonds are common two-center two-electron bonds (2N-2D mu).