Combined Photoemission Spectroscopy and Scanning Tunneling Microscopy Study of the Sequential Dehydrogenation of Hexahydroxytriphenylene on Ag(111)

The structural evolution of 2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) single-layer networks on Ag(111) was investigated by scanning tunneling microscopy and core-level photoemission. The molecules adsorbed in flat-lying conformation and formed well-ordered supramolecular domains. Three different phases were observed depending on the substrate temperature during deposition. Core-level photoemission showed that the radical changes in the supramolecular networks corresponded to different degrees of dehydrogenation of the six-fold hydroxyl functional groups borne by the molecule. Remarkably, hydroxyl groups involved in strong H bonding with carbonyl oxygens appeared as distinct components in the O 1s spectra.