title: Formation of Organometallic Intermediate States in On-Surface Ullmann Couplings.
abstract: Possible origins of the formation of organometallic intermediates in on-surface Ullmann couplings have been investigated by surface tunneling microscopy (STM) and density functional theory (DFT) calculations. We consider the case of iodobenzenes on the coinage metals copper, silver, and gold. We found experimental evidence for the formation of surface vacancies and the presence of metal adatoms in these coupling reactions, which are taken as a hint for the reactive extraction of surface atoms by adsorbates. In a second step, we demonstrate by ab initio molecular dynamics calculations for aryl-iodides on copper that metal atoms can be pulled out of the surface to form metal-organic species. By contrast, a thermally activated provision of a metal atom from the surface to form an adatom is energetically unfavorable. Finally, we investigate the mechanism and energetics of the reactive extraction of surface metal atoms by means of (climbing-image) nudged elastic band density-functional theory calculations for iodobenzene on copper, silver, and gold, and analyze our results in the light of the experimental findings.
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.|Center for Multiscale Theory and Computation (CMTC), Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Barton
authors.affiliation: Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149, Münster (Germany) and Center for Nanotechnology (CeNTech), Heisenbergstraße 11, 48149 Münster, Germany.
authors.forename: Hong-Ying
authors.initials: HY
authors.lastname: Gao
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
authors.forename: Philipp Alexander
authors.initials: PA
authors.lastname: Held
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
authors.forename: Armido
authors.initials: A
authors.lastname: Studer
authors.affiliation: Center for Multiscale Theory and Computation (CMTC), Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.|Physikalisches Institut, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149, Münster (Germany) and Center for Nanotechnology (CeNTech), Heisenbergstraße 11, 48149 Münster, Germany.|Institute for Nanotechnology, Karlsruhe Institute of Technology, 76344, Karlsruhe, Germany.
authors.forename: Harald
authors.initials: H
authors.lastname: Fuchs
authors.affiliation: Center for Multiscale Theory and Computation (CMTC), Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.|Institut für Festkörpertheorie, Westfälische Wilhelms-Universität Münster, Wilhelm-Klemm-Straße 10, 48149, Münster, Germany.
authors.forename: Nikos L
authors.initials: NL
authors.lastname: Doltsinis
authors.affiliation: Organisch-Chemisches Institut, Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.|Center for Multiscale Theory and Computation (CMTC), Westfälische Wilhelms-Universität Münster, Corrensstraße 40, 48149, Münster, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Neugebauer
keywords: Ullmann coupling; coinage metals; density funtional calculations; surface analysis