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O: Fachverband Oberflächenphysik
O 74: Nanostructured Surfaces and Thin Films I: Synthesis and Properties (joint session O/CPP)
O 74.10: Vortrag
Mittwoch, 18. März 2020, 17:15–17:30, WIL B321
Methyl and Vinyl Functional Groups in On-Surface Synthesis — •Marco Di Giovannantonio1, José I. Urgel1, Shantanu Mishra1, Kristjan Eimre1, Aliaksandr V. Yakutovich1, Carlo A. Pignedoli1, Pascal Ruffieux1, Uliana Beser2, Qiang Chen2, Zijie Qiu2, Akimitsu Narita2, Klaus Müllen2, and Roman Fasel1,3 — 1Empa - Swiss Federal Laboratories for Materials Science and Technology, nanotech@surfaces Laboratory, 8600 Dübendorf, Switzerland — 2Max Planck Institute for Polymer Research, 55128 Mainz, Germany — 3Department of Chemistry and Biochemistry, University of Bern, 3012 Bern, Switzerland
On-surface synthesis has opened pathways to molecular nanostructures that have been inaccessible so far. Here, we demonstrate the successful use of methyl and vinyl groups to achieve one-dimensional (1D) polymers composed of repeat units with specific ring topologies.
Methyl groups are proven to undergo an oxidative cyclization to the neighboring phenyl, forming five-membered rings and affording unprotected indenofluorene isomers, some of which exhibit high radical character. Vinyl groups enable the formation of additional six-membered rings, affording benzo[k]tetraphene units after a stable intermediate with CH2 groups protruding out of five-membered rings.
The structure and electronic properties of the obtained polymers have been characterized by STM, nc-AFM, and STS, and supported by theoretical calculations. The observed reaction steps and products extend the knowledge of on-surface reactions to fine tune architectures and functionalities.