Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 7: Focus Session: Functional Molecules at Surfaces I
O 7.12: Talk
Monday, March 16, 2020, 13:30–13:45, TRE Ma
CO ligation to Ru tetraphenylprorphyrins on Ag(111) — •Peter Knecht1, Joachim Reichert1, Peter Deimel1, Peter Feulner1, Felix Haag1, Francesco Allegretti1, Manuela Garnica1, Martin Schwarz1, Willi Auwärter1, Paul Ryan2, David A. Duncan2, Ari P. Seitsonen3, Johannes V. Barth1, and Anthoula C. Papageorgiou1 — 1Physics Department E20, Technical University of Munich, Germany — 2Diamond Light Source, UK — 3Chemistry Department, ENS Paris, France
For the creation of novel materials and devices, inspiration is frequently sought in nature. Porphyrin molecules are macrocyclic compounds of biological origin, which incorporate a large fraction of the chemical elements. Their versatile properties stimulated widespread application to surface functionalisation.1 In biology, the binding of small molecules to metal centres of porphyrins determines many vital functions. For Ru tetraphenyl porphyrins (Ru-TPP), CO is determined to have an unusually high ligation energy (1.9 eV).2 Here we study the effect of the porphyrin surface environment on this ligation for Ru-TPP on Ag(111). We use scanning tunnelling microscopy to find a cis-carbonyl ligation3 at low temperatures and an axial ligation at higher temperatures, which is also examined with temperature programmed desorption. We correlate the axial binding to conformational and electronic changes, investigated by density functional theory, X-ray photoemission and X-ray standing waves.
1) Nat. Chem. 2015, 7, 105; 2) Phys. Chem. Chem. Phys. 2018, 20, 11730; 3) Nat. Chem. 2011, 3, 114.