Self-Assembled Monolayers of N-Heterocyclic Olefins on Au(111)

Iris Berg, Luca Schio, Justus Reitz, Elena Molteni, Linoy Lahav, Carolina Gutiérrez Bolaños, Andrea Goldoni, Cesare Grazioli, Guido Fratesi, Max M. Hansmann, Luca Floreano, Elad Gross*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Self-assembled monolayers (SAMs) of N-heterocyclic olefins (NHOs) have been prepared on Au(111) and their thermal stability, adsorption geometry, and molecular order were characterized by X-ray photoelectron spectroscopy, polarized X-ray absorption spectroscopy, scanning tunneling microscopy (STM), and density functional theory (DFT) calculations. The strong σ-bond character of NHO anchoring to Au induced high geometrical flexibility that enabled a flat-lying adsorption geometry via coordination to a gold adatom. The flat-lying adsorption geometry was utilized to further increase the surface interaction of the NHO monolayer by backbone functionalization with methyl groups that induced high thermal stability and a large impact on work-function values, which outperformed that of N-heterocyclic carbenes. STM measurements, supported by DFT modeling, identified that the NHOs were self-assembled in dimers, trimers, and tetramers constructed of two, three, and four complexes of NHO−Au-adatom. This self-assembly pattern was correlated to strong NHO−Au interactions and steric hindrance between adsorbates, demonstrating the crucial influence of the carbon-metal σ-bond on monolayer properties.

Original languageAmerican English
Article numbere202311832
JournalAngewandte Chemie - International Edition
Volume62
Issue number46
DOIs
StatePublished - 13 Nov 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.

Keywords

  • N-Heterocyclic Olefins
  • Scanning Tunneling Microscopy
  • Self-Assembled Monolayers
  • Surface Chemistry
  • X-Ray Absorption Spectroscopy

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