Efficient and recyclable carbon-supported Pd nanocatalysts for the Suzuki-Miyaura reaction in aqueous-based media: Microwave vs conventional heating

Three new hybrid nanocatalysts based on carbon-supported Pd nanoparticles (NPs) were prepared by decomposition of an organometallic palladium precursor under H₂ atmosphere in the presence of carbon materials with different surface and textural properties. The so-obtained Pd NPs displayed mean sizes in the range of 2-2.5 nm. The hybrid nanocatalysts were evaluated in the aqueous Suzuki-Miyaura cross-coupling reaction under both conventional and microwave heating. Excellent activities were obtained at short reaction times (5-10 min) reaching TOF values up to 3000 h^-1 under microwave radiation. Recycling studies showed that the nanocatalysts could be re-used up to 10 (conventional heating) and to 5 (microwave irradiation) reaction cycles without any loss of activity. The reaction media was found to have a strong influence on the recyclability of the nanocatalysts, which could be improved in the presence of polyethylene glycol.