NHCs on planar metal surfaces
Self-assembled NHC monolayers on gold. In several publications (Nature Communications 2021, Chemistry a European Journal 2020, and Nature Chemistry 2014), we described the first examples of well-formed carbon-based monolayers on gold surfaces. Despite their widespread use in catalysis, N-heterocyclic carbenes (NHCs) have seen scarce applications in materials chemistry. In molecular transition metal complexes, they are known by their abilities to form strong metal–carbon bonds, making NHC complexes more resistant to heat and oxidation than typical complexes. With the assumption that these properties would translate to materials, we attempted the synthesis of self-assembled monolayers on gold and found that sterically unencumbered carbenes form monolayers that are significantly more stable than the state-of-the-art sulfur-based films. The NHC films are stable to high temperature, refluxing solvent, boiling acid, base and oxidation with dilute hydrogen peroxide. The work was called "game changing" and "the new gold standard" by international experts, and highlighted in chemistry and physics news magazines including Chemical and Engineering News (US), Physics Today (UK), Chemistry World (UK), Canadian Chemical News (CDN) and others.
Since these original studies, we have developed methods to prepare high quality films using a single component precursor in air, without any special precautions. Films can also be deposited in vacuo without any solvents. With these easily formed films, we also demonstrated the formation of biosensors that were significantly more robust, reliable and sensitive than commercial biosensors. Efforts to expand this into the protection of metal surfaces at all length scales are underway in my lab and in partnership with the C2MCI. Industrial partners include companies interested in corrosion prevention and coatings, along with the semiconductor industry.