title: Imaging Successive Intermediate States of the On-Surface Ullmann Reaction on Cu(111): Role of the Metal Coordination.
abstract: The in-depth knowledge about on-surface reaction mechanisms is crucial for the tailor-made design of covalently bonded organic frameworks, for applications such as nanoelectronic or -optical devices. Latest developments in atomic force microscopy, which rely on functionalizing the tip with single CO molecules at low temperatures, allow to image molecular systems with submolecular resolution. Here, we are using this technique to study the complete reaction pathway of the on-surface Ullmann-type coupling between bromotriphenylene molecules on a Cu(111) surface. All steps of the Ullmann reaction, i.e., bromotriphenylenes, triphenylene radicals, organometallic intermediates, and bistriphenylenes, were imaged with submolecular resolution. Together with density functional theory calculations with dispersion correction, our study allows to address the long-standing question of how the organometallic intermediates are coordinated via Cu surface or adatoms.
authors.affiliation: Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany.
authors.forename: Sören
authors.initials: S
authors.lastname: Zint
authors.affiliation: Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany.
authors.forename: Daniel
authors.identifier: 0000-0001-5829-170X
authors.initials: D
authors.lastname: Ebeling
authors.forename: Tobias
authors.initials: T
authors.lastname: Schlöder
authors.forename: Sebastian
authors.initials: S
authors.lastname: Ahles
authors.forename: Doreen
authors.initials: D
authors.lastname: Mollenhauer
authors.forename: Hermann A
authors.initials: HA
authors.lastname: Wegner
authors.affiliation: Institute of Applied Physics (IAP), Justus Liebig University Giessen , Heinrich-Buff-Ring 16, 35392 Giessen, Germany.
authors.forename: André
authors.initials: A
authors.lastname: Schirmeisen
keywords: CO tip; atomic force microscopy; density functional theory; on-surface Ullmann coupling; reaction pathway; submolecular resolution imaging