Iminyl-Radical-Mediated Formation of Covalent Au–N Bonds for Molecular Junctions

• DOI: 10.1021/jacs.3c00453
• Publication Date: 2023-03-08T03:44:11Z
• Authors: Mingliang Zhang; Junfeng Lin; Kai Song; Kaili Chang; Xiaojuan Dai; Yaping Zang; Daoben Zhu

The interaction between organic radicals and transition metals plays a crucial role in radical-mediated chemical reactions, functional devices, and biocatalysis. Characterizing such interactions, however, remains a long-standing challenge due to the inherently high reactivity of radical species. Here, using a scanning tunneling microscope breaking junction (STM-BJ) technique, we are able to detect the interaction mode between iminyl radicals and the gold surface at a single molecule level. We show that the free iminyl radicals generated through photochemical N-O bond homolysis of oxime esters react toward the gold electrode surface and produce covalent Au-N bonds. Intriguingly, we find that the Au-N bonding reactions lead to the formation of robust and highly conductive single-molecule junctions. These findings provide not only insights into the mechanism of iminyl-radical-involved reactions but also a facile photolysis method to create a new type of covalent electrode-molecule bonding contact for molecular devices.