H. Walch, T. Leoni, O. Guillermet, V. Langlais, J. Bonvoisin, A. Scheuermann and S. Gauthier
Abstract:
We use a Scanning Tunneling Microscope (STM) tip to reversibly switch between two stable states the organometallic complex bis‐dibenzoylmethanato‐copper (Cu(dbm)2) adsorbed on a thin insulating film on different metal surfaces (Cu(111) and Ag(111)). The switching is due to the capture (or loss) of an electron and accompanied by a conformational change, i.e. a transition from a square‐planar to a tetrahedral geometry. Evidence is given by STM topography and spectroscopy and non‐contact Atomic Force Microscopy (nc‐AFM) charge measurement. Similar experiments conducted on bis‐dibenzoylmethanato‐nickel (Ni(dbm)2) show that the nickel complex does not switch under comparable experimental conditions. We discuss these findings within the framework of crystal field theory stating that the occupation of the d‐orbitals determines the favored coordination geometry of a complex. Accordingly only the copper complex can undergo a conformational change that facilitates stable storing of the additional electron.
CNRS, CEMES Centre d’Elaboration des Matériaux et d’Etudes Structurales