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O: Fachverband Oberflächenphysik
O 5: Dynamics of Molecules on Surfaces
O 5.6: Talk
Monday, March 7, 2016, 11:45–12:00, S053
Force-induced tautomerization in a single molecule — •Janina N. Ladenthin1, Thomas Frederiksen2, 3, Mats Persson4, Sylwester Gawinkowski5, Jacek Waluk5, and Takashi Kumagai1 — 1Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Berlin, Germany. — 2Donostia International Physics Center, San Sebastián, Spain. — 3IKERBASQUE, Basque Foundation for Science, Bilbao, Spain. — 4Surface Science Research Centre and Department of Chemistry, University of Liverpool, UK. — 5Institute of Physical Chemistry, Polish Academy of Sciences, Warsaw, Poland.
Chemical reactions can be activated by heat, electric or light energy. Force is another way but the fundamental process of mechanical activation is much less studied. Force-induced bond breaking and formation are the elementary steps in mechanochemical reactions. However, it remains poorly understood at the single-molecule level. In the talk, we present the force-induced intramolecular H-atom transfer (tautomerization) in a single porphycene molecule on the Cu(110) surface at 5 K using nc-AFM. Porphycene is an intriguing model system for studies of tautomerization [1]. Force spectroscopy was employed to quantify the force needed to trigger the cis-cis tautomerization, revealing a few hundred pN. It was also found that the tautomerization cannot be induced with a Xe-terminated tip, indicating the importance of chemical forces. Furthermore, DFT calculations elucidated the atomistic mechanism behind the force-induced tautomerization.
[1] T. Kumagai et al. PRL 111, 246101 (2013); T. Kumagai et al. Nature Chem. 6, 41 (2014); T. Kumagai, Prog. Surf. Sci. 90, 239 (2015).