title: Force-induced tautomerization in a single molecule.
abstract: Heat transfer, electrical potential and light energy are common ways to activate chemical reactions. Applied force is another way, but dedicated studies for such a mechanical activation are limited, and this activation is poorly understood at the single-molecule level. Here, we report force-induced tautomerization in a single porphycene molecule on a Cu(110) surface at 5 K, which is studied by scanning probe microscopy and density functional theory calculations. Force spectroscopy quantifies the force needed to trigger tautomerization with submolecular spatial resolution. The calculations show how the reaction pathway and barrier of tautomerization are modified in the presence of a copper tip and reveal the atomistic origin of the process. Moreover, we demonstrate that a chemically inert tip whose apex is terminated by a xenon atom cannot induce the reaction because of a weak interaction with porphycene and a strong relaxation of xenon on the tip as contact to the molecule is formed.
authors.affiliation: Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: Janina N
authors.initials: JN
authors.lastname: Ladenthin
authors.affiliation: Donostia International Physics Center (DIPC) - UPV/EHU, E-20018, San Sebastián, Spain.|IKERBASQUE, Basque Foundation for Science, E-48013, Bilbao, Spain.
authors.forename: Thomas
authors.identifier: 0000-0001-7523-7641
authors.initials: T
authors.lastname: Frederiksen
authors.affiliation: Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: Mats
authors.initials: M
authors.lastname: Persson
authors.affiliation: Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: John C
authors.initials: JC
authors.lastname: Sharp
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland.
authors.forename: Sylwester
authors.initials: S
authors.lastname: Gawinkowski
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland.|Faculty of Mathematics and Natural Sciences, College of Science, Cardinal Stefan Wyszyński University, Dewajtis 5, 01-815 Warsaw, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Waluk
authors.affiliation: Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany.
authors.forename: Takashi
authors.initials: T
authors.lastname: Kumagai