By means of scanning tunnelling microscopy (STM), complementary density functional theory (DFT) and X-ray photoelectron spectroscopy (XPS) we investigate the binding and self-assembly of a saturated molecular layer of model -heterocyclic carbene (NHC) on Cu(111), Ag(111) and Au(111) surfaces under ultra-high vacuum (UHV) conditions. XPS reveals that at room temperature, coverages up to a monolayer exist, with the molecules engaged in metal carbene bonds. On all three surfaces, we resolve similar arrangements, which can be interpreted only in terms of mononuclear M(NHC) (M = Cu, Ag, Au) complexes, reminiscent of the paired bonding of thiols to surface gold adatoms. Theoretical investigations for the case of Au unravel the charge distribution of a Au(111) surface covered by Au(NHC) and reveal that this is the energetically preferential adsorption configuration.
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| http://dx.doi.org/10.1039/c7sc03777e | DOI Listing |
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