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O: Fachverband Oberflächenphysik

O 103: Poster Session VIII: Surface reactions II

O 103.7: Poster

Thursday, March 4, 2021, 13:30–15:30, P

Highly selective synthesis of enetriyne via tetramerization of terminal alkynes on Ag(100) — Nan Cao¹, •Biao Yang¹, Jonas Björk², and Johannes V. Barth¹ — ¹Physics Department E20, Technical University of Munich, D-85748 Garching, Germany — ²Department of Physics, Chemistry and Biology, IFM, Linköping University, 58183 Linköping (Sweden)

Enetriyne, a conjugated species of eneyne family, is a prominent constituent in the antibiotic and antitumor sector. On-surface synthesis under ultrahigh vacuum, which can be monitored by real space scanning probe microscopy and other techniques, has been widely used as a powerful tool to disentangle and control reaction pathways on well-defined interfaces. We herein report a novel approach of enetriyne formation with high selectivity via tetramerization of terminal alkynes on Ag(100). Taking advantage of a hydroxyl directing group, we managed to steer the reaction process and obtain a uniform product. Firstly, upon O2 exposure the adsorbed precursor's terminal alkyne moieties deprotonate, which entails the formation of organometallic dimer. Secondly, controlled annealing of the pretreated sample induces the formation of the tetrameric species, which self-assembles in regular islands stabilized by lateral weak interactions. We combine STM, XPS studies and DFT calculations to examine the newly formed covalent compounds and suggest a reaction mechanism. Our study provides a protocol, involving a directing group, gas-mediated pretreatment, and an excitation reaction to precisely fabricate a functional enetriyne species.