title: Epitaxy-Induced Assembly and Enantiomeric Switching of an On-Surface Formed Dinuclear Organocobalt Complex.
abstract: We report on the surface-guided synthesis of a dinuclear organocobalt complex, its self-assembly into a complex nanoarchitecture, and a single-molecule level investigation of its switching behavior. Initially, an organic layer is prepared by depositing hexakis((trimethylsilyl)ethynyl)-benzene under ultrahigh-vacuum conditions onto Ag(111). After Co dosage at 200 K, low-temperature scanning tunneling microscopy (STM) reveals an epitaxy-mediated organization mechanism of molecules and on-surface formed organometallic complexes. The dinuclear complexes contain two bis(η2-alkynyl) π-tweezer motifs, each stabilizing a single Co atom and express two enantiomers due to a conformation twist. The chirality is transferred to the two-dimensional architecture, whereby its Co adatoms are located at the corners of a 3.4.6.4 rhombitrihexagonal tessellation due to the systematic arrangement and anchoring of the complexes. Extensive density functional theory simulations support our interpretation of an epitaxy-guided surface tessellation and its chiral character. Additionally, STM tip-assisted manipulation experiments on isolated dinuclear complexes reveal controlled and reversible switching between the enantiomeric states via inelastic electron processes. After activation by bias pulses, structurally modified complexes display a distinctive Kondo feature attributed to metastable Co configurations.
authors.affiliation: Physik Department E20, Technische Universität München , Garching D-85748, Germany.
authors.forename: Raphael
authors.initials: R
authors.lastname: Hellwig
authors.affiliation: Physik Department E20, Technische Universität München , Garching D-85748, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Paintner
authors.affiliation: Institute of Nanotechnology, Karlsruhe Institute of Technology , Eggenstein-Leopoldshafen D-76344, Germany.
authors.forename: Zhi
authors.initials: Z
authors.lastname: Chen
authors.affiliation: Institute of Nanotechnology, Karlsruhe Institute of Technology , Eggenstein-Leopoldshafen D-76344, Germany.|Institute de Physique et Chimie de Matériaux de Strasbourg (IPCMS), CNRS-Université de Strasbourg , Strasbourg F-67034, France.
authors.forename: Mario
authors.identifier: 0000-0002-7718-7016
authors.initials: M
authors.lastname: Ruben
authors.affiliation: Département de Chimie, Ecole Normale Supérieure (ENS) , Paris Cedex 05 F-75230, France.
authors.forename: Ari Paavo
authors.identifier: 0000-0003-4331-0650
authors.initials: AP
authors.lastname: Seitsonen
authors.affiliation: Physik Department E20, Technische Universität München , Garching D-85748, Germany.
authors.forename: Florian
authors.identifier: 0000-0002-2877-6105
authors.initials: F
authors.lastname: Klappenberger
authors.affiliation: Institute of Physics, Ecole Polytechnique Fédérale de Lausanne (EPFL) , Station 3, Lausanne CH-1015, Switzerland.|Institute for Advanced Study (TUM-IAS) , Lichtenbergstr. 2a, Garching D-85748, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Brune
authors.affiliation: Physik Department E20, Technische Universität München , Garching D-85748, Germany.
authors.forename: Johannes V
authors.initials: JV
authors.lastname: Barth
keywords: cobalt alkynyl complex; scanning tunneling microscopy; single-molecule switch; surface tessellation