Berlin 2015 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 89: Inorganic/Organic Interfaces: Molecular Switches
O 89.13: Vortrag
Donnerstag, 19. März 2015, 18:00–18:15, MA 043
Direct observation of intramolecular H-atom transfer reaction by scanning tunneling microscopy — •Janina Ladenthin1, Leonhard Grill1,2, Jacek Waluk3, and Takashi Kumagai1 — 1Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany. — 2Department of Physical Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria. — 3Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland.
Intramolecular H-atom transfer reaction, i.e. tautomerization, is an important molecular process in chemistry and biology. More recently tautomerization in free-base phthalocyanine [1] and porphyrin derivatives [2,3] was directly observed and controlled by low-temperature STM. We have studied tautomerization within a single porphycene molecule, which is a structural isomer of porphine but there exist H-bonding interaction in the cavity, adsorbed on Cu(111) by low-temperature STM. After the deposition of porphycene molecule onto the surface at room temperature the adsorption structure and dynamics were investigated at 5 K. The molecules show the thermodynamically favorable trans configuration. A voltage pulse of the STM can induce the unidirectional conversion from the trans to cis configuration, interestingly, which occurs non-locally and the spatial range of the reaction reaches up to ~100 nm from the STM tip position.
[1] P. Liljeroth, J. Repp, G. Meyer, Science 317, 1203 (2007). [2] W. Auwärter et al. Nature Nanotech. 7, 41 (2011). [3] T. Kumagai et al. Nature Chem. 6, 41 (2014).