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O: Fachverband Oberflächenphysik

O 73: Organic Molecules on Inorganic Substrates V: Adsorption, Growth and Networks

O 73.8: Vortrag

Mittwoch, 18. März 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.