Adatom mediated adsorption of N‐heterocyclic carbenes on Cu(111) and Au(111). Issue 6 (30th December 2021)

• Record Type: Journal Article
• Authors: Jain, Mitisha; Gerstmann, Uwe; Schmidt, Wolf Gero; Aldahhak, Hazem
• Is Part Of: Journal of computational chemistry. Volume 43:Issue 6(2022)
• Page Start: 413
• Page End: 420
• Publication Date: 2021-12-30
• Subjects: adatoms -- DFT -- M(111) surfaces -- N‐heterocyclic carbenes -- side groups; Chemistry -- Data processing -- Periodicals; 542.85
• DOI: 10.1002/jcc.26801
• Languages: English
• ISSNs: 0192-8651

Abstract

Abstract: The adsorption of N‐heterocyclic carbenes (NHCs) on Cu(111) and Au(111) surfaces is studied with density‐functional theory. The role of the molecular side groups as well as the surface morphology in determining the adsorption geometry are explored in detail. Flat‐laying NHCs, as observed experimentally for NHC with relatively small side groups, result from the adsorption at adatoms and give rise to the so‐called ballbot configurations, which are more stable than adsorption on flat surfaces and provide an efficient precursor for the formation of bis(NHC) dimers. On Au(111), the resulting (NHC)2 Au complexes are purely physisorbed and thus mobile. On the more reactive Cu(111), in contrast, the central Cu atom in the (NHC)2 Cu dimer is still covalently bound to the surface, resulting in a mobility, which has to be thermally activated. Abstract : The geometries of N‐heterocyclic carbenes are mainly driven by the size of the side groups. Relatively small side groups (blue) assist the flat‐laying geometries. However, bulky side groups (red) prefer upright adsorption geometries. The existence of an adatom is crucial for this process.