Dresden 2020 – scientific programme
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O: Fachverband Oberflächenphysik
O 73: Organic Molecules on Inorganic Substrates V: Adsorption, Growth and Networks
O 73.8: Talk
Wednesday, March 18, 2020, 17:00–17:15, TRE Phy
Self-assembly, metalation and oxidation of a novel macrocyclic compound on Ag(111) — •Felix Haag1, Peter Deimel1, Raphael Lauenstein2, Manuel Kaspar2, Johannes Barth1, Corinna Hess2, and Francesco Allegretti1 — 1Physics Department E20, Technical University Munich, Germany — 2Chemistry Department, Technical University Munich, Germany
We report the first experimental study of the adsorption of the free-base macrocyclic biquinazoline (H-mabiq) on a model solid surface. This tetraaza-macrocycle offers two potential coordination sites combined with multi-electron transfer capacity - properties reaching beyond the well-studied surface-confined metallo-porphyrins and -phthalocyanine systems. Those coordination sites can be occupied by different metal atoms, rendering adsorbed mabiq complexes promising candidates for photocatalytic applications as well as epoxidation reactions.
Here, we report on the bonding and self-assembly of H-mabiq on Ag(111) by using X-ray photoelectron spectroscopy (XPS), low-energy electron diffraction (LEED) and temperature programmed desorption (TPD). We confirm the molecular integrity and establish protocols for well-ordered single layers and controlled metalation with Co atoms. A number of long-range ordered structures are identified, depending critically on molecular and metal coverage. Furthermore, reversible cycling between different phases is observed by tuning the H-mabiq surface density and the temperature. Finally, the interaction of adsorbed H-Mabiq and Co-mabiq with dioxygen is compared.