title: Site-Dependent Coordination Bonding in Self-Assembled Metal-Organic Networks.
abstract: The combination of organic linkers with metal atoms on top of inorganic substrates offers promising perspectives for functional electronic and magnetic nanoscale devices. Typically, coordination bonds between electron-rich end groups and transition-metal atoms lead to the self-assembly of metal-organic nanostructures, whose shape and electronic and magnetic properties crucially depend on the type of ligand. Here, we report on the site-selective bonding properties of Co atoms to the dichotomic dicyanoazobenzene molecule with its carbonitrile and diazo N-based moieties as possible ligands. Using low-temperature scanning tunneling microscopy (STM) and spectroscopy measurements, we resolve the formation of self-assembled metal-organic motifs. Cobalt atoms exhibit a clear spectroscopic fingerprint dependent on the different coordination site, which is further used to map their position, otherwise not clearly visible in the topographic STM images. Density functional theory corroborates the observed bonding patterns and evidences their coordinative nature.
authors: †Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors: N
authors: N
authors: Henningsen
authors: ‡Institut de Ciència de Materials de Barcelona (ICMAB-CSIC), Campus de Bellaterra, 08193 Bellaterra (Barcelona), Spain.
authors: R
authors: R
authors: Rurali
authors: †Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors: C
authors: C
authors: Limbach
authors: †Institut für Experimentalphysik, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors: R
authors: R
authors: Drost
authors: §Institut für Experimentalphysik and Center for Supramolecular Interactions (CSI Berlin), Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors: J I
authors: JI
authors: Pascual
authors: §Institut für Experimentalphysik and Center for Supramolecular Interactions (CSI Berlin), Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany.
authors: K J
authors: KJ
authors: Franke
keywords: azobenzene; coordination bonding at surfaces; density functional thoery; metal−organic networks; scanning tunneling microscopy; single-molecule spectroscopy