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Abstract
Chemical reactions that occur at nanostructured electrodes have garnered widespread interest because of their potential applications in fields including nanotechnology, green chemistry and fundamental physical organic chemistry. Much of our present understanding of these reactions comes from probes that interrogate ensembles of molecules undergoing various stages of the transformation concurrently. Exquisite control over single-molecule reactivity lets us construct new molecules and further our understanding of nanoscale chemical phenomena. We can study single molecules using instruments such as the scanning tunnelling microscope, which can additionally be part of a mechanically controlled break junction. These are unique tools that can offer a high level of detail. They probe the electronic conductance of individual molecules and catalyse chemical reactions by establishing environments with reactive metal sites on nanoscale electrodes. This Review describes how chemical reactions involving bond cleavage and formation can be triggered at nanoscale electrodes and studied one molecule at a time.
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Borca B, Michnowicz T, Pétuya R, Pristl M, Schendel V, Pentegov I, Kraft U, Klauk H, Wahl P, Gutzler R, Arnau A, Schlickum U, Kern K. Electric-Field-Driven Direct Desulfurization. ACS NANO 2017; 11:4703-4709. [PMID: 28437066 DOI: 10.1021/acsnano.7b00612] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
The ability to elucidate the elementary steps of a chemical reaction at the atomic scale is important for the detailed understanding of the processes involved, which is key to uncover avenues for improved reaction paths. Here, we track the chemical pathway of an irreversible direct desulfurization reaction of tetracenothiophene adsorbed on the Cu(111) closed-packed surface at the submolecular level. Using the precise control of the tip position in a scanning tunneling microscope and the electric field applied across the tunnel junction, the two carbon-sulfur bonds of a thiophene unit are successively cleaved. Comparison of spatially mapped molecular states close to the Fermi level of the metallic substrate acquired at each reaction step with density functional theory calculations reveals the two elementary steps of this reaction mechanism. The first reaction step is activated by an electric field larger than 2 V nm-1, practically in absence of tunneling electrons, opening the thiophene ring and leading to a transient intermediate. Subsequently, at the same threshold electric field and with simultaneous injection of electrons into the molecule, the exergonic detachment of the sulfur atom is triggered. Thus, a stable molecule with a bifurcated end is obtained, which is covalently bound to the metallic surface. The sulfur atom is expelled from the vicinity of the molecule.
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Affiliation(s)
- Bogdana Borca
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
- National Institute of Materials Physics , 077125 Măgurele-Ilfov, Romania
| | - Tomasz Michnowicz
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Rémi Pétuya
- Donostia International Physics Centre , E-20018 Donostia - San Sebastián, Spain
| | - Marcel Pristl
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Verena Schendel
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Ivan Pentegov
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Ulrike Kraft
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Hagen Klauk
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Peter Wahl
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
- SUPA, School of Physics and Astronomy, University of St. Andrews , North Haugh, St. Andrews KY16 9SS, United Kingdom
| | - Rico Gutzler
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Andrés Arnau
- Donostia International Physics Centre , E-20018 Donostia - San Sebastián, Spain
- Departamento de Física de Materiales UPV/EHU and Material Physics Center (MPC), Centro Mixto CSIC-UPV/EHU , E-20018 Donostia - San Sebastián, Spain
| | - Uta Schlickum
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
| | - Klaus Kern
- Max Planck Institute for Solid State Research , 70569 Stuttgart, Germany
- Institut de Physique , École Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
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Simic-Milosevic V, Mehlhorn M, Morgenstern K. Imaging the Bonds of Dehalogenated Benzene Radicals on Cu(111) and Au(111). Chemphyschem 2016; 17:2679-85. [PMID: 27272737 DOI: 10.1002/cphc.201600495] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2016] [Indexed: 11/07/2022]
Abstract
Dissociative adsorption of doubly substituted benzene molecules leads to formation of benzyne radicals. In this study, co-adsorbed hydrogen molecules are used in scanning tunneling hydrogen microscopy to enhance the contrast of the meta- and the para-isomers of these radicals on Cu(111) and Au(111). Up to three hydrogen molecules are attached to one radical. One hydrogen molecule reveals the orientation of the carbon ring and its adsorption site, allowing discrimination between the two radicals. Two hydrogen molecules reflect the bond picture of the carbon skeleton and reveals that adsorption on Cu(111) distorts the meta- isomer differently from its gas-phase distortion. Three hydrogen molecules allow us to determine the bond picture of a minor species.
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Affiliation(s)
| | - Michael Mehlhorn
- Institut für Experimentalphysik, FU Berlin, Arnimallee 14, D-14195, Berlin, Germany
| | - Karina Morgenstern
- Institut für Experimentalphysik, FU Berlin, Arnimallee 14, D-14195, Berlin, Germany. .,Ruhr-Universität Bochum, Lehrstuhl für Physikalische Chemie I, D-44780, Bochum, Germany.
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Godlewski S, Kawai H, Engelund M, Kolmer M, Zuzak R, Garcia-Lekue A, Novell-Leruth G, Echavarren AM, Sanchez-Portal D, Joachim C, Saeys M. Diels-Alder attachment of a planar organic molecule to a dangling bond dimer on a hydrogenated semiconductor surface. Phys Chem Chem Phys 2016; 18:16757-65. [PMID: 27271337 DOI: 10.1039/c6cp02346k] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Construction of single-molecule electronic devices requires the controlled manipulation of organic molecules and their properties. This could be achieved by tuning the interaction between the molecule and individual atoms by local "on-surface" chemistry, i.e., the controlled formation of chemical bonds between the species. We demonstrate here the reversible attachment of a planar conjugated polyaromatic molecule to a pair of unpassivated dangling bonds on a hydrogenated Ge(001):H surface via a Diels-Alder [4+2] addition using the tip of a scanning tunneling microscope (STM). Due to the small stability difference between the covalently bonded and a nearly undistorted structure attached to the dangling bond dimer by long-range dispersive forces, we show that at cryogenic temperatures the molecule can be switched between both configurations. The reversibility of this covalent bond forming reaction may be applied in the construction of complex circuits containing organic molecules with tunable properties.
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Affiliation(s)
- Szymon Godlewski
- Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, PL 30-348, Krakow, Poland.
| | - Hiroyo Kawai
- Institute of Materials Research and Engineering, 2 Fusionopolis Way, Innovis, #08-03, Singapore 138634, Singapore.
| | - Mads Engelund
- Centro de Fisica de Materiales CSIC-UPV/EHU, Paseo Manual de Lardizabal 5, E-20018, Donostia-San Sebastian, Spain
| | - Marek Kolmer
- Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, PL 30-348, Krakow, Poland.
| | - Rafal Zuzak
- Centre for Nanometer-Scale Science and Advanced Materials, NANOSAM, Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Lojasiewicza 11, PL 30-348, Krakow, Poland.
| | - Aran Garcia-Lekue
- Donostia International Physics Center, Paseo Manual de Lardizabal 4, 20018, Donostia-San Sebastian, Spain and IKERBASQUE, Basque Foundation for Science, E-48013, Bilbao, Spain
| | - Gerard Novell-Leruth
- Laboratory for Chemical Technology, Ghent University, Technologiepark 914, 9052 Ghent, Belgium
| | - Antonio M Echavarren
- Institute of Chemical Research of Catalonia (ICIQ), Avenida Països Catalans 16, 43007 Tarragona, Spain
| | - Daniel Sanchez-Portal
- Centro de Fisica de Materiales CSIC-UPV/EHU, Paseo Manual de Lardizabal 5, E-20018, Donostia-San Sebastian, Spain and Donostia International Physics Center, Paseo Manual de Lardizabal 4, 20018, Donostia-San Sebastian, Spain
| | - Christian Joachim
- Nanosciences Group & MANA Satellite, CEMES-CNRS, 29 rue Jeanne Marvig, F-31055 Toulouse, France and International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki 305-0044, Japan
| | - Mark Saeys
- Laboratory for Chemical Technology, Ghent University, Technologiepark 914, 9052 Ghent, Belgium
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Motobayashi K, Kim Y, Arafune R, Ohara M, Ueba H, Kawai M. Dissociation pathways of a single dimethyl disulfide on Cu(111): Reaction induced by simultaneous excitation of two vibrational modes. J Chem Phys 2014; 140:194705. [DOI: 10.1063/1.4875537] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Henzl J, Boom K, Morgenstern K. Reorientation of a single bond within an adsorbed molecule by tunneling electrons. J Am Chem Soc 2013; 135:11501-4. [PMID: 23895214 DOI: 10.1021/ja405809f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Scanning tunneling microscopy offers the exciting possibility to manipulate individual molecules by vibrational excitation via inelastically tunneling electrons. The electrons transfer energy into molecular vibrational modes, leading to breakage or formation of individual bonds. It is challenging to precisely control intramolecular changes by this process. We demonstrate that for 4,4'-dihydroxyazobenzene adsorbed on Au(111) or Ag(111), the manipulation facilitates rotation of the OH end groups around the C-O bond between metastable states; this corresponds to a reorientation of the hydrogen, the ultimate limit of a conformational change within a molecule.
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Affiliation(s)
- Jörg Henzl
- Abteilung für Atomare und Molekulare Strukturen (ATMOS), Institut für Festkörperphysik, Leibniz Universität Hannover, Appelstr. 2, D-30167 Hannover, Germany
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