Regensburg 2010 – wissenschaftliches Programm

Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe

O: Fachverband Oberflächenphysik

O 85: Metal substrates: Adsorption of organic / bio molecules VII

O 85.1: Vortrag

Freitag, 26. März 2010, 11:15–11:30, H36

Thin films and monolayers of metalloporphyrines and -phthalocyanines: Examination of the reactive sites — •Martin Schmid, Yun Bai, Michael Sekita, Hans-Peter Steinrück, and J. Michael Gottfried — Universität Erlangen-Nürnberg, Lehrstuhl für Physikalische Chemie II, Egerlandstr. 3, 91058 Erlangen, Germany

Planar metal complexes such as metalloporphyrins and -phthalocyanines show various chemical and structural properties that make them promising candidates for many technological purposes, ranging from gas sensors and catalytic applications to molecular electronic devices. In the absence of axial ligands, those complexes possess coordinatively unsaturated central metal ions which then play a key role as reactive and/or coordinative sites. For a detailed mechanistic understanding of the electronic interactions, especially at the central metal ion, we prepared thin films and monolayers of Co, Fe and Cu porphyrines and -phthalocyanines under ultrahigh vacuum conditions on Ag(111) and Au(111) single crystal surfaces. The systems were analyzed by UV and X-ray photoelectron spectroscopy; these methods are sensitive to the valence electronic structure of the interface and to the oxidation states of the metal centers, respectively. Our investigations revealed that changes in the chemical environment, e.g., by coordination of small reactive molecules such as O₂ and CO, as well as subtle differences in the molecular geometry, the nature of the substrate, and even temperature variations can alter the oxidation state of the metal center and the character of its interaction with the substrate.