Figure shows the O 1s and C 1s XPS spectra for both samples after a 10 minutes air exposure and with subsequent annealing at 370 K for 15 min. In the case of the oligomers synthesized in vacuum at 370 K on Au(111), the C 1s spectrum after air exposure (middle spectra in graph) is very similar to the one obtained before the exposure (bottom spectra), indicating that the oligomers preserve their integrity. Interestingly, it is still possible to discern the C-Au peak (yellow curve) associated to the metal-organic oligomers. Their integrity is further supported by the absence of an O peak (left side, orange curves), which it is well-known to be the most reactive species when organic structures are exposed to air . To confirm the integrity of the oligomers and their stability, the exposed sample was further annealed at 370 K (top spectra), resulting in a C 1s spectrum almost identical to that obtained before the annealing. The Ag(111) case is interestingly different: upon air exposure, both the O 1s and C 1s peaks change. In the former case, we see the appearance of an O 1s emission composed of two contributions located at 530.5 eV and 532.0 eV. The one at lower BE is assigned to AgO and physisorbed O2, in good agreement with literature , while the one at higher BE is compatible with oxygen species bonded to organic C . Furthermore, two important changes occur in the C 1s spectrum. The first one is the almost complete disappearance of the C-Ag component (black curve at 283.1 eV). The second one is the appearance of a new component at 287.3 eV (light green curve), which is consistent with the formation of carbon-oxygen bonds, in accordance with the result obtained for the O 1s peak. Thus, both results indicate the rupture of the metal-organic oligomers and the possible stabilization of the system with the incorporation of oxygen-containing species.