Electronic Structure and Charge Transport Properties of N-Heterocyclic Carbenes on Au

N-heterocyclic carbenes (NHCs) enable the fabrication of robust self-assembled monolayers on gold substrates that can outperform thiol-based counterparts. Here, we study the metal-molecule interactions and electronic structure of NHCs on an Au (111) surface using X-ray photoelectron spectroscopy, single-molecule transport and density functional theory. Through X-ray measurements and density functional theory, we reveal how steric constraints introduced by different ancillary substitutions shape the interaction of NHCs with Au and steer the molecular adsorption geometry. By means of the scanning tunneling microscope break-junction method, we investigate the formation and charge transport properties of NHC-terminated molecular conductors, demonstrating that these carbenes can function as novel and robust linker groups for single-molecule electronics.