Synthesis of Imines by Selective Oxidation of Amines on alloy nanoparticles of palladium and gold under visible light irradiation at ambient temperatures

Imines are important intermediates in organic synthesis. To avoid derivatives, the research on direct oxidized amines as an alternative method is imminent. The gold (Au)–palladium (Pd) alloy nanoparticles (NPs) catalyst shows a favourable activity and high selectivity on benzylamine oxidation reaction under light irradiation. The yield of the reaction on the alloy NPs with a Au:Pd ratio of 1:1.86 in the dark was 36% at 45 °C, while the yield increased to 95% under light illumination. The study demonstrates different properties from alloy NP to pure Au NP and Pd NP catalysts which may be caused by increased surface charge heterogeneity in the alloy system. The conversion rate of the reaction can also be enhanced by light irradiation and heat. The light energy which utilized by Localized Surface Plasmon Resonance effect of gold in alloy system can highly enhanced the efficiency of reaction. These findings provide useful guidelines for designing efficient alloy catalysts with a plasmonic metal and a catalytically active transition metal for various organic syntheses driven by sunlight. Graphic Abstract