On-Surface Alcohol Formation from a Carbene Precursor

A microscopic understanding of on-surface reactions involving highly reactive intermediates is challenging because the intermediate quickly loses its reactivity after its creation via charge transfer from or to the surface. This binding to the surface competes with a bimolecular reactivity whenever the reaction partner is not in the immediate vicinity. It is even more true for reactions involving more than two reaction partners, for instance, the synthesis of alcohol from a reaction of a carbene with water, a reaction that involves three water molecules. We demonstrate that fluorenol can be photolytically formed on a surface at low temperature from a carbene precursor 9-diazo fluorene with water on Ag(111) using scanning tunneling microscopy and density functional calculation. At an excess of water, the precursor reacts with water to fluorenol at a temperature as low as 80 K. The same reaction is induced at 11 K via ultraviolet photolysis of the precursor bonded in inverse solvent–solute complexes to fractal water islands. Our study demonstrates that complex on-surface reactions, including several water molecules, are feasible with a carbene as a highly reactive intermediate despite its high affinity to electrons drawn from the metal surface.