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ChemRXiVArticleJune 23_5.pdf (1.68 MB)
Self-Assembly of N-Heterocyclic Carbenes on Au(111)
Preprints are manuscripts made publicly available before they have been submitted for formal peer review and publication. They might contain new research findings or data. Preprints can be a draft or final version of an author's research but must not have been accepted for publication at the time of submission.
submitted on 23.06.2020 and posted on 25.06.2020by Alex Inayeh, Ryan Groome, Ishwar Singh, Alex Veinot, Felipe Iima, Roberto Miwa, Cathleen Crudden, Alastair McLean
The production of ordered arrays of organic molecules on
metallic surfaces by means of self-assembly is one of the
most powerful methods for controlled patterning on the
nanometer scale. Although the self-assembly of sulfurbased ligands has been studied for decades, the thermal
and oxidative instability of these systems introduces
challenges in many potential applications. In recent
years, it has been shown that a new ligand class,
N-heterocyclic carbenes (NHCs), bind to metal surfaces
via a metal–carbon covalent bond, resulting in
monolayers with much greater stability. However,
fundamental questions surrounding self-assembly in this
new ligand class remain unanswered, including the simple
questions of what controls NHC orientation on the
surface and under what conditions they self-assemble.
Herein we describe how NHC structure, surface density,
deposition temperature, and annealing temperature
control mobility, thermal stability, NHC surface
geometry, self-assembly, and the exact chemical nature of
the surface structures. These data provide the first general
set of guidelines to enable the rational design of highly
ordered NHC-based monolayers. Considering that NHCs
may supplant thiols as the functionalization agent of
choice in a wide range of applications, a detailed
understanding of their surface chemistry is crucial for the
success of these next-generation monolayers.