title: Controlling intramolecular hydrogen transfer in a porphycene molecule with single atoms or molecules located nearby.
abstract: Although the local environment of a molecule can play an important role in its chemistry, rarely has it been examined experimentally at the level of individual molecules. Here we report the precise control of intramolecular hydrogen-transfer (tautomerization) reactions in single molecules using scanning tunnelling microscopy. By placing, with atomic precision, a copper adatom close to a porphycene molecule, we found that the tautomerization rates could be tuned up and down in a controlled fashion, surprisingly also at rather large separations. Furthermore, we extended our study to molecular assemblies in which even the arrangement of the pyrrolic hydrogen atoms in the neighbouring molecule influences the tautomerization reaction in a given porphycene, with positive and negative cooperativity effects. Our results highlight the importance of controlling the environment of molecules with atomic precision and demonstrate the potential to regulate processes that occur in a single molecule.
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
authors.affiliation: 1] Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK [2].
authors.forename: Felix
authors.initials: F
authors.lastname: Hanke
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: Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: John
authors.initials: J
authors.lastname: Sharp
authors.affiliation: Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kotsis
authors.affiliation: Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, Warsaw 01-224, Poland.
authors.forename: Jacek
authors.initials: J
authors.lastname: Waluk
authors.affiliation: 1] Surface Science Research Centre and Department of Chemistry, University of Liverpool, Liverpool L69 3BX, UK [2] Department of Applied Physics, Chalmers University of Technology, 41296 Göteborg, Sweden.
authors.forename: Mats
authors.initials: M
authors.lastname: Persson
authors.affiliation: 1] Department of Physical Chemistry, Fritz-Haber Institute of the Max-Planck Society, Faradayweg 4-6, 14195 Berlin, Germany [2] Department of Physical Chemistry, University of Graz, Heinrichstrasse 28, 8010 Graz, Austria.
authors.forename: Leonhard
authors.initials: L
authors.lastname: Grill
mesh_terms: D006859:Hydrogen / Q000737:chemistry*; D016252:Microscopy, Scanning Tunneling; D011166:Porphyrins / Q000737:chemistry*
chemical_list: D011166:Porphyrins; C051407:porphycene; D006859:Hydrogen