Influence of radical initiators in gold catalysis: Evidence supporting trapping of radicals derived from azobis(isobutyronitrile) by gold halides

Gold halides (AuCl3, HAuCl4, and AuCl) efficiently trap the radicals generated in the room-temperature photolysis of azobis(isobutyronitrile) (AIBN) to give an organogold H[(CH3)2CCN]2AuCl2 compound that has been characterized by spectroscopy. The characteristic features of the organogold are a quaternary carbon at 100 ppm on 13C NMR and a HR-MS peak with a molecular formula of C8H13N2AuCl. Catalytic data for cyclohexene aerobic oxidation confirms the beneficial influence of the presence of AIBN on the catalytic activity of Au/CeO2.