Design and Characterization of an Electrically Powered Single Molecule on Gold.

The surface diffusion of individual molecules is of paramount importance in self-assembly processes and catalytic processes. However, the fundamental understanding of molecule diffusion peculiarities considering conformations and adsorption sites remain poorly known at the atomic-scale. Here, we probe 4'-(4-tolyl)-2,2':6',2"-terpyridine adsorbed on the Au(111) herringbone structure combining scanning tunneling microscopy and atomic force microscopy. Molecules are controllably translated by electrons excitations over the reconstruction, except at elbows acting as pinning centres. Experimental data supported by theoretical calculations show there the formation of coordination bonds between the molecule and Au atoms of the surface. Using force spectroscopy, we quantify an increase of the lateral force for displacing the molecule of ∼ 280 pN corresponding to an elevation of the diffusion barrier of ∼ 100 meV compared to the rest of the surface.