Azo bond formation on metal surfaces

The formation of azo compounds via redox cross-coupling of nitroarenes and arylamines, challenging in solution phase chemistry, is achieved by on-surface chemistry. Reaction products are analyzed with a cryogenic scanning tunneling microscope (STM) and X-ray photoelectron spectroscopy (XPS). By using well-designed precursors containing both an amino and a nitro functionality, azo polymers are prepared on surface via highly efficient nitro-amino cross-coupling. Experiments conducted on other substrates and surface orientations reveal that the metal surface has a significant effect on the reaction efficiency. The reaction was further found to proceed from partially oxidized/reduced precursors in dimerization reactions, shedding light on the mechanism that was studied by DFT calculations.

Automated summary

The efficient formation of azo compounds via redox cross-coupling of nitroarenes and arylamines has been achieved through on-surface chemistry. The use of well-designed precursors containing both an amino and a nitro functionality results in highly efficient nitro-amino cross-coupling on the surface. The metal surface was found to have a significant effect on the reaction efficiency, with the reaction proceeding from partially oxidized/reduced precursors in dimerization reactions.