Dresden 2011 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Aktualisierungen | Downloads | Hilfe
O: Fachverband Oberflächenphysik
O 27: Metal substrates: Adsorption of organic / bio molecules IV
O 27.5: Vortrag
Dienstag, 15. März 2011, 12:15–12:30, PHY C213
Compensation of the odd-even effects in araliphatic monomolecular films by non-symmetric attachment of the aromatic part — John Dauselt1, Jianli Zhao2, Martin Kind1, Robert Binder1, Andreas Terfort1, and •Michael Zharnikov2 — 1Institut für Anorganische und Analytische Chemie, Universität Frankfurt, Max-von-Laue-Straße 7, 60438 Frankfurt, Germany — 2Angewandte Physikalische Chemie, Universität Heidelberg, 69120 Heidelberg, Germany
The integrity, chemical identity, packing density, and molecular orientation in SAMs formed by anthracene-substituted alkanethiols (Ant-n) with a variable number of methylene groups (n) in the aliphatic linker on Au(111) and Ag(111) substrates were studied by a combination of several complementary experimental techniques. The Ant-n molecules were found to form well-defined and highly ordered SAMs on these substrates, with very small inclination of the anthracene backbone. In addition, the Ant-n SAMs exhibited odd-even effects, i.e. dependence of the molecular orientation and packing density on the length of the aliphatic linker, with the parity of n being the decisive parameter. Whereas the direction (sign) of this odd-even behavior on gold and silver is the same as for SAMs of biphenyl- and terphenyl-substituted alkanethiolates and alkaneselenolates, the extent of the odd-even effects in the Ant-n films is noticeably smaller than in the latter systems. This behaviour can be explained by the additional rotational degree of freedom of the anthracene unit in the case of the Ant-n SAMs due to its non-symmetrical attachment to the adjacent alkyl linker.