On the adsorption of different tetranaphthylporphyrins on Cu(111) and Ag(111)

We address the adsorption of 2H-tetranaphthylporphyrin (2HTNP) and 2H-tetranaphthylbenzoporphyrin (2HTNBP) on Cu(111) and Ag(111). The difference between the two molecules is that for 2HTNBP the pyrrole groups are replaced by isoindole groups. We were interested in the resulting differences in the adsorption behavior on the two surfaces, in particular the role of the naphthyl groups. The investigations are performed with scanning tunneling microscopy at room temperature (RT) and after heating treatments (500 and 600 K). On Ag (111), 2HTNP forms a commensurable superstructure at RT, which transforms to a denser packed, noncommensurable structure upon annealing. For 2HTNBP, individual molecules are observed on Cu(111) at RT, which exhibit different mobility. In contrast, on Ag(111) the formation of ordered 2HTNBP islands occurs, which are stabilized by T-type interactions. After heating to 500 K, these islands undergo a structural change to a denser packed structure, which is stabilized by 7C-7C stacking of neighboring naphthyl groups.

Automated summary

We investigated the adsorption behavior of 2H-tetranaphthylporphyrin (2HTNP) and 2H-tetranaphthylbenzoporphyrin (2HTNBP) on Cu(111) and Ag(111) surfaces. The molecules showed different adsorption behavior on the two surfaces, with the formation of superstructures on Ag(111) and individual molecules on Cu(111). Heating treatments led to structural changes in the adsorbates.