Highly ordered N-heterocyclic carbene monolayers on Cu(111)

14 December 2021, Version 2
This content is a preprint and has not undergone peer review at the time of posting.


The benzannulated N-heterocyclic carbene, 1,3-dibenzylbenzimidazolylidene (NHCDBZ) forms large, highly ordered domains when adsorbed on a Cu(111) surface under ultrahigh vacuum conditions. A combination of scanning tunneling microscopy (STM), high resolution electron energy loss spectroscopy (HREELS) and density functional theory (DFT) calculations reveals that the overlayer consists of vertical benzannulated NHC moieties coordinating to Cu adatoms. Long range order results from the placement of the two benzyl units from a single NHC on opposite sides of the benzimidazole moiety, with the planes of their aromatic rings approximately parallel to the surface. The organization of three surface-bound benzyl substituents from three different NHCs into a triangular array controls the formation of a highly ordered Kagome-like lattice on the surface. This study illustrates the importance of dispersive interactions to control the binding geometry and self-assembly of the NHC.


N-heterocyclic carbenes
self-assembled monolayers
surface chemistry
scanning tunneling microscopy

Supplementary materials

Supporting Information
Synthetic details for NHC-DBZ, supplementary STM images and analysis, supplementary HREELS plots and details for DFT calculation methods.


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