Electrodeposition of N-Heterocyclic Carbene on Mild Steel Surfaces

Abstract

N-Heterocyclic carbenes (NHCs) are promising molecules for functionalizing and protecting metals, ranging from single crystals to polycrystalline samples. However, the functionalization of complex surfaces, such as mild steel (MS), a widely used industrial material, has only been scarcely explored, with only one prior report. Herein, we present a simple and highly reproducible electrochemical method to anchor NHCs onto MS surfaces. Two different NHC precursors are employed: iPrNHC•H2CO3 (1,3-diisopropylbenzimidazolium hydrogen carbonate) and iPrNHCAlk•H2CO3 (1,3-diisopropyl-5-(prop-2-yn-1-yloxy)-1H-benzo[d]imidazol-3-ium hydrogen carbonate). Our electrochemical approach enables the controlled generation of nucleophiles at the interface between solvated NHCs and the MS surface. By tuning the electrochemical deposition parameters, we are able to optimize surface functionalization by regulating the generation of reactive oxygen species (ROS), and hydroxyl ions (OH-). The resulting NHC coatings are characterized using microscopy, spectroscopy, and combined techniques such as AFM-IR. Stability tests reveal that these coatings are resistant to highly alkaline conditions.