Electrochemical deposition of N-heterocyclic carbene monolayers on metal surfaces.

Amit, Einav; Dery, Linoy; Dery, Shahar; Kim, Suhong; Roy, Anirban; Hu, Qichi; Gutkin, Vitaly; Eisenberg, Helen; Stein, Tamar; Mandler, Daniel; Dean Toste, F.; Gross, Elad

N-heterocyclic carbenes (NHCs) have been widely utilized for the formation of self-assembled monolayers (SAMs) on various surfaces. The main methodologies for preparation of NHCs-based SAMs either requires inert atmosphere and strong base for deprotonation of imidazolium precursors or the use of specifically-synthesized precursors such as NHC(H)[HCO3] salts or NHC–CO2 adducts. Herein, we demonstrate an electrochemical approach for surface-anchoring of NHCs which overcomes the need for dry environment, addition of exogenous strong base or restricting synthetic steps. In the electrochemical deposition, water reduction reaction is used to generate high concentration of hydroxide ions in proximity to a metal electrode. Imidazolium cations were deprotonated by hydroxide ions, leading to carbenes formation that self-assembled on the electrode's surface. SAMs of NO2-functionalized NHCs and dimethyl-benzimidazole were electrochemically deposited on Au films. SAMs of NHCs were also electrochemically deposited on Pt, Pd and Ag films, demonstrating the wide metal scope of this deposition technique. N-heterocyclic carbenes (NHCs) have been widely used for the formation of monolayers but self-assembly methods come with drawbacks such as need for dry environment or using specifically-synthesized precursors. Here, the authors demonstrate an approach for surface-anchoring of NHCs which overcomes these limitations by using electrochemically-assisted deprotonation.

METALLIC surfaces; MONOMOLECULAR films; CARBENES; PRECIOUS metals; PROTON transfer reactions

Nature Communications, 2020, Vol 11, Issue 1, pN.PAG

2041-1723

Academic Journal

10.1038/s41467-020-19500-7