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O: Fachverband Oberflächenphysik
O 56: Metal substrates: Adsorption of organic / bio molecules VI
O 56.1: Vortrag
Mittwoch, 24. März 2010, 15:00–15:15, H36
Electron induced conformational changes of imine-based molecular switches on a Au(111) surface — •Christian Lotze1, Ying Luo2, Rainer Haag2, and Jose Ignacio Pascual1 — 1Inst. f. Experimentalphysik, Freie Universität Berlin — 2Inst. f. organische Chemie, Freie Universität Berlin
Organic molecules exhibiting controllable reversible transitions between isomeric states on surfaces promise an enormous potential in the field of molecular electronics. The reversible cis-trans isomerization of azobenzene-like molecules is often hindered by a strong interaction of the nitrogen lone-pair electrons of the di-azo bridge (-N=N-) with the substrate. In order to improve the isomerization capabilities, the di-azo bridge is substituted by an imine-group (-N=CH-).
Here, we use low-temperature scanning tunneling microscopy to investigate a sub-monolayer of the newly designed imine-based molecular switch NPCI on a Au(111) surface. Its carboxylic termination mediates the formation of hydrogen-bonded dimers, which align in rows along the herringbone reconstruction. We were able to induce reversible conformational changes with the tunneling electrons from the STM tip and determine its efficiency as a function of electron energy.