N-Heterocyclic carbenes on close-packed coinage metal surfaces: bis-carbene metal adatom bonding scheme of monolayer films on Au, Ag and Cu. Issue 12 (24th October 2017)

• Record Type: Journal Article
• Authors: Jiang, Li; Zhang, Bodong; Médard, Guillaume; Seitsonen, Ari Paavo; Haag, Felix; Allegretti, Francesco; Reichert, Joachim; Kuster, Bernhard; Barth, Johannes V.; Papageorgiou, Anthoula C.
• Is Part Of: Chemical science. Volume 8:Issue 12(2017)
• Page Start: 8301
• Page End: 8308
• Publication Date: 2017-10-24
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c7sc03777e
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : N -Heterocyclic carbenes wet the solid surfaces of group 11 metals with energetically favourable electron donating biscarbene metal complexes. Abstract : 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 N -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)2 (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)2 and reveal that this is the energetically preferential adsorption configuration.