Following our design criteria, we chose to study the per-thiolated derivate of β-cyclodextrin, 1, on gold as a model for host binding close to the surface (Figure a), as this molecule has been thoroughly studied for its surface-functionalization and surface HGC formation behaviour on gold. As guests, we chose to investigate ruthenium-based electrocatalyst 2, inspired by the class of molecular catalysts that has very recently been shown to be active for ammonia oxidation in organic electrolytes (ammonia being a promising candidate as storage medium for hydrogen). We also investigated structurally similar ruthenium-based electrocatalyst 3, a derivate of which we have reported to be active for water oxidation. As a control, fluorescent platinum complex 4 was synthesized, which served as a non-electroactive guest. The complexes used in this study and their crystal structures are given in Figure . The common design feature in the guest metal complexes is the naphthyl substitution on the terpyridine ligand, which was employed as the binding unit of the guests inside the cyclodextrin cavity. To confirm that binding between the guests and cyclodextrin takes place in solution, fluorescence titrations and NMR experiments were performed (see Figures and in Supporting Info). A 1:1 stoichiometry binding constant for fluorescent guest 4 with β-CD was determined and a binding constant of K 11 = 6.5•10 3 M -1 was obtained, which is 2-4 times higher than for other naphthyl-based guests with β-CD. The attachment of 1 on gold substrate was investigated by X-ray photoelectron spectroscopy (XPS) (Figure ) and tip-enhanced Raman spectroscopy (TERS) (vide infra). The spectra indicated the expected attachment of the cyclodextrin host via the thiol groups, as was evidenced by the loss of the ν(S-H) Raman band upon adsorption. The surface density of 1 on Au(111) determined by XPS was found to be up to 0.46 nm -2 , corresponding to a relatively compact layer of host molecules on the substrate. We note that the maximum coverage of the surface was achieved with dipping times of 3 minutes, with no further increase in the surface coverage of 1 at longer exposure of the gold substrate (Figure ).