title: Selective formation of cumulative double bonds (C[double bond]C[double bond]N) in the attachment of multifunctional molecules on Si(111)-7 x 7.
abstract: The cumulative double bond (C[double bond]C[double bond]N), an important intermediate in synthetic organic chemistry, was successfully prepared via the selective attachment of acrylonitrile to Si(111)-7 x 7. The covalent binding of acrylonitrile on Si(111)-7 x 7 was studied using high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), scanning tunneling microscopy (STM) and DFT calculations. The observation of the characteristic vibrational modes and electronic structures of the C[double bond]C[double bond]N group in the surface species demonstrates the [4 + 2]-like cycloaddition occurring between the terminal C and N atoms of acrylonitrile and the neighboring adatom-rest atom pair, consistent with the prediction of DFT calculations. STM studies further show the preferential binding of acrylonitrile on the center adatom sites of faulted halves of Si(111)-7 x 7 unit cells.
authors.affiliation: Department of Chemistry, National University of Singapore, 10 Kent Ridge, Singapore, 119260.
authors.forename: Feng
authors.initials: F
authors.lastname: Tao
authors.forename: Xian Feng
authors.initials: XF
authors.lastname: Chen
authors.forename: Zhong Hai
authors.initials: ZH
authors.lastname: Wang
authors.forename: Guo Qin
authors.initials: GQ
authors.lastname: Xu