title: Si-C(N) sigma linkages and N --> Si dative bonding at pyridine/Si(111)-7 x 7.
abstract: We experimentally demonstrated that pyridine/Si(111)-7 x 7 can act as an electron donor/acceptor pair as a result of the charge transfer from the electron-rich N atom of pyridine to the electron-deficient adatom of the Si surface, evidenced by the upshift of 1.8 eV (state A) for the N(1s) core level upon the formation of a datively bonded complex compared to physisorbed molecules. Another state (B) whose N(1s) binding energy downshifts by 1.2 eV was assigned to an adduct through Si-C and Si-N covalent linkages, formed via a [4 + 2]-like addition mechanism on Si(111)-7 x 7. Binding molecules through the formation of the dative bond resulted from significant electron transfer opens a new approach for the creation of Si-based molecular architectures and modification of semiconductor interfacial properties with unsaturated organic molecules.
authors.affiliation: Department of Chemistry, National University of Singapore, Singapore 119260.
authors.forename: Feng
authors.initials: F
authors.lastname: Tao
authors.forename: Yee Hing
authors.initials: YH
authors.lastname: Lai
authors.forename: Guo Qin
authors.initials: GQ
authors.lastname: Xu