Unraveling the molecular conformations of a single ruthenium complex adsorbed on the Ag(111) surface by calculations

Abstract

The tris(dibenzoylmethanato)ruthenium (Ru(dbm)₃) molecule has recently been characterized by scanning tunneling microscopy (STM) experiments upon adsorption on Ag(111). The adsorbed Ru(dbm)₃ molecule shows two conformations with respect to the [10] direction of the substrate, one with a three-lobed feature and the other one with a bi-lobed structure. For each of these structures, the molecule can take two geometries (states). Molecular mechanics calculations in a semi-empirical framework and STM calculated images reveal that these states on the substrate originate from the enantiomer of the Ru(dbm)₃ molecule in the case of three-lobed structure and from the rotation of the two phenyls in the top dbm moities for the bi-lobed form.