Dresden 2006 – scientific programme
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O: Oberflächenphysik
O 14: Poster session I (Adsorption, Epitaxy and growth, Phase transitions, Surface reactions, Organic films, Electronic structure, Methods) (sponsored by Omicron Nanotechnology GmbH)
O 14.43: Poster
Monday, March 27, 2006, 18:00–21:00, P2
Structure and Reactivity of Metalloporphyrins on a Ag(111) Surface — •K. Flechtner1, T. Lukasczyk1, L. Merte1, J. M. Gottfried1, H.P. Steinrück1, T. Shubina2, and T. Clark2 — 1Universität Erlangen-Nürnberg, Lehrstuhl für Physikalische Chemie II, Egerlandstr. 3, D-91058 Erlangen, Germany — 2Universität Erlangen-Nürnberg, Chemie-Computer-Centrum, Nägelsbachstrasse 2, 91052 Erlangen, Germany
Metalloporphyrins are among the most abundant organometallic compounds in nature and control various biochemical reactions. The decisive step in these reactions is often the attachment of a ligand on the central metal atom. Here, we investigate adsorbate layers of Tetraphenylporphyrin-Co(II) and Tetrakis-(3,5-di-tert-butylphenyl)porphyrin-Co(II) as model compounds for natural porphyrin systems. In particular, we report an XPS and LEED study of the growth of the porphyrins on Ag(111), the preparation of ordered monolayers, and their thermal stability. The Co 2p3/2 photoemission signal consists of four peaks corresponding to different final states and/or different oxidation states of the Co ion. Monolayers show an additional Co 2p3/2 peak that probably reflects the Co(II)-Ag interaction. Both porphyrins form ordered monolayers. Furthermore, we examined the adsorption of small molecules such as H2O, NH3, CO, and NO at the Co ion of the porphyrins. For comparison with our experimental data, we also computed the ligand-to-metal binding energies of these molecules with DFT. Likewise, we studied the properties of Zn(II)-porphyrin layers. This work was supported by the DFG through SFB 583.