Radical mechanism of a place-exchange reaction of Au nanoparticles

Spin-trapping experiments show the formation of sulfur-centered radicals during a ligand-exchange reaction between Ph3P-protected Au nanoparticles and alkanethiols in air (see picture). Oxidation of the alkanethiols by molecular O2 adsorbed on the nanoparticles is proposed as the key step. The feasibility of such a process is demonstrated by the Au-nanoparticle-catalyzed oxidation of BH4- and tBuOOH with air.