Dresden 2009 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 4: Metal substrates: Adsorption of organic / bio molecules I
O 4.7: Vortrag
Montag, 23. März 2009, 12:45–13:00, SCH A118
Electron induced conformational changes of an imine-based molecular switch on a Au(111) surface — •Christian Lotze1, Nils Henningsen1, Katharina Franke1, Gunnar Schulze1, Ying Luo2, Rainer Haag2, and Jose Ignacio Pascual1 — 1Inst. f. Experimentalphysik, Freie Universität Berlin, Germany — 2Inst. f. organische Chemie, Freie Universität Berlin, Germany
Azobenzene-based molecules exhibit a cis-trans configurational photoisomerisation in solution. Recently, the adsorption properties of azobenzene derivatives have been investigated on different metal surfaces in order to explore the possible changes in the film properties induced by external stimuli. In azobenzene, the diazo-bridge is a key group for the isomerization process. Its interaction with a metal surface is dominated through the N lone-pair electrons [1], which reduces the efficiency of the conformational change. In order to reduce the molecule-surface interaction, we explore an alternative molecular architecture by substituting the diazo-bridge (-N=N-) of azobenzene by an imine-group (-N=CH-). We have investigated the imine-based compound para-carboxyl-di-benzene-imine (PCI) adsorbed on a Au(111) surface. The carboxylic terminations mediates the formation of strongly bonded molecular dimers, which align in ordered rows preferentially following the fcc regions of the Au(111) herringbone reconstruction. Low temperature scanning tunneling microscopy was used to induce conformational changes between trans and cis state of individual molecules in a molecular monolayer. [1] N. Henningsen, R. Rurali, K. J. Franke, I. Fernández-Torrente, and J. I. Pascual, Appl. Phys. A 93, 241 (2008)