One-Pot Photoreactions: A Source for Metal-Polymer Nanocomposites

We have developed a one-step, one-pot photo-induced method for synthesizing metal/polymer nanocomposites. This approach utilizes the photolysis of a bis(acyl)phosphane oxide (BAPO) photoinitiator. Two types of radicals are formed. One initiates a radical polymerization while the other acts as a reducing agent in aqueous or alcoholic media. As a result, metal nanoparticles are formed in situ during polymerization and become embedded within the growing polymer matrix. This simultaneous formation and incorporation lead to the direct immobilization of metal centers, yielding stable nanocomposites. In this proof-of-principle study, we established mechanistic details and characterized the composites. We have evaluated their activity in well-established catalytic reactions. Here, Pd composites were used for Suzuki coupling, Cu for alkyne-azide coupling (CuAAC), and Ag for the reduction of 4-nitrophenol. The results confirm that the nanocomposites exhibit catalytic activity. Our methodology offers a versatile and easily tunable platform for the synthesis of nanocomposites. Any monomer amenable to radical polymerization can be employed, and a wide range of metal salts can be reduced via the photo-initiated process. The syntheses are rapid (approximately 10 minutes), require no hazardous solvents or complex reaction conditions, and enable straightforward work-up.