N-Heterocyclic Carbenes Reduce and Functionalize Copper Oxide Surfaces in a Single Step

Benzimidazolium hydrogen carbonate salts have been shown to act as N-heterocyclic carbene precursors which can remove oxide from copper oxide surfaces and functionalize the resulting metallic surfaces in a single step. Both the surfaces and the etching products are fully characterized by spectroscopic methods. Analysis of surfaces before and after NHC treatment by X-ray photoelectron spectroscopy demonstrates the complete removal of copper(II) oxide. Using ¹³C-labelling, we determine that the products of this transformation include a cyclic urea, a ring-opened formamide and a bis-carbene copper(I) complex. These results illustrate the potential of NHCs to functionalize a much broader class of metals, including those prone to oxide treatment, greatly facilitating the preparation of NHC-based films on metals other than gold.