N-Heterocyclic Carbenes as Clickable Molecular Anchors for Electrochemical Surface Functionalization

The potential of alkyne-containing NHCs as anchor molecules for electrochemical surface modification is investigated. Using X-ray photoelectron spectroscopy, fluorescence tagging, and shell-isolated enhanced Raman spectroscopy, we demonstrate that these NHCs can bind effectively to multiple surfaces and be functionalized via electrochemical copper-catalyzed azide-alkyne cycloaddition. Notably, we extend this approach beyond metals and demonstrate its applicability to glassy carbon. A comparison with alkyne-containing diazonium salts shows that NHCs result in lower surface coverage/passivation, making NHCs better-suited for electrochemical applications. The versatility of alkyne-functionalized NHCs as molecular anchors for various surfaces is demonstrated through the attachment of electrochemically active TEMPO•, the immobilization of streptavidin, and the formation of copper coatings. These findings highlight the potential of NHCs as alternatives to thiols and diazonium salts for the design of functional materials, electrodes, and biosensors.