Synthesis and study of the catalytic applications in C–C coupling reactions of hybrid nanosystems based on alumina and palladium nanoparticles

Hybrid materials based on Pd nanoparticles supported onto nanorods of alumina have been synthesized, characterized and tested in Suzuki–Miyaura C–C coupling catalytic reactions observing good conversion rates, a high Pd loading influence and a good degree of recyclability in consecutive catalytic cycles. [Display omitted] •Pd-nanoparticles have been supported onto alumina-based nanomaterials.•Hybrid Pd-alumina materials have been characterized by different methods.•The catalytic activity of the hybrid materials has been tested in C–C coupling.•Catalytic tests have been carried out studying the Pd loading influence.•Hybrid materials show a good degree of recyclability in consecutive catalytic tests. Nanostructured alumina has been treated under mild conditions with different quantities of [PdCl2(cod)] (cod=1,5-cyclooctadiene) to promote the formation of supported palladium nanoparticles which have been characterized by XRD, XRF, BET and TEM. The results show that the new hybrid materials, nano-Al2O3-Pd-20 and nano-Al2O3-Pd-50, consist of impregnated palladium nanoparticles onto aggregates of nanoparticles of alumina. The catalytic activity of the hybrid Pd-alumina materials has been tested in Suzuki–Miyaura C–C coupling reactions observing good conversion rates in the reactions of 3-bromoanisole with 4-carboxyphenylboronic acid or 4-vinylphenylboronic acid. The catalytic studies have been extended with experiments investigating the Pd loading influence. Catalyst recyclability tests show a slight decrease in activity after the first cycle in the reaction of 3-bromoanisole with 4-vinylphenylboronic acid. However, subsequent activity remains almost constant after five more consecutive catalytic cycles.