“…14 Consequently, there are many works focusing on the spectroscopic characterization of NHCs including benzimidazolium salts, 15,16 imidazolium salts, 17 free carbene moieties, 18 and CO 2 adducts. 19 Vibrational spectroscopies such as high-resolution electron energy loss spectroscopy (HREELS), 11,20 surface-enhanced Raman spectroscopy (SERS), 21,22 and reflection absorption infrared (IR) spectroscopy (RAIRS) 23,24 have been applied as a tool to study NHC SAMs. They are often used to monitor monolayer formation and stability, 24,25 surface chemical reactions, 26,27 and catalysis.…”