Zinc-Porphine on Coinage Metal Surfaces: Adsorption Configuration and Ligand-Induced Central Atom Displacement

We present a comprehensive, quantitative multimethod characterization of the geometric and electronic interfacial structure of zinc-porphine (Zn-P) on coinage metal supports, namely, Ag(111) and Cu(111). Complementary techniques including X-ray standing waves, X-ray photoelectron spectroscopy, scanning tunneling microscopy, bond resolved atomic force microscopy, and density functional theory calculations reveal the molecular conformations, signal a temperature-dependence of element-specific adsorption heights, rule out a decisive role of the d10 nature of the Zn center for the adsorption configuration, and uncover a considerably increased Zn-P adsorption height on Ag(111) compared to Cu(111). Furthermore, a pronounced out-of-plane displacement of the Zn center upon water ligation is demonstrated, a manifestation of the surface trans-effect. This study thus sheds light on effects of temperature, chemical nature of the metal center, its ligation, and the coinage metal support on interfacial structure and molecular deformation of an archetypical surface-anchored metal-tetrapyrrole.

Automated summary

We provide a comprehensive and quantitative characterization of the interfacial structure of zinc-porphine (Zn-P) on Ag(111) and Cu(111) supports. Various techniques reveal the molecular conformations, temperature-dependence of adsorption heights, and the impact of metal nature and ligation on the interfacial structure. This study sheds light on the effects of different factors on the molecular deformation of a surface-anchored metal-tetrapyrrole.