Abstract
In a combined scanning tunneling microscopy (STM) and noncontact atomic force microscopy (nc-AFM) study, we characterize the reversible switching between two stable states of an organometallic complex, namely, bis-dibenzoylmethanato-copper [Cu(dbm)] adsorbed on an insulating thin film. The switching is due to the transfer of an electron between the STM tip and the molecule, 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 nc-AFM electrostatic force measurements. Similar experiments conducted on bis-dibenzoylmethanato-nickel [Ni(dbm)] show that this 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 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.
2 More- Received 31 May 2012
DOI:https://doi.org/10.1103/PhysRevB.86.075423
©2012 American Physical Society