Dual application of Pd nanoparticles supported on mesoporous silica SBA-15 and MSU-2: supported catalysts for C-C coupling reactions and cytotoxic agents against human cancer cell lines

Two different mesoporous silica-based materials (SBA-15 and MSU-2) have been treated under mild conditions with different quantities of [PdCl2(cod)] (cod = 1,5-cyclooctadiene) to promote the formation of supported palladium nanoparticles (materials of the type SBA-15-Pd and MSU-2-Pd). The synthesized materials have been characterized by different techniques observing that the palladium nanoparticles remain impregnated in the silica. The catalytic activity of the hybrid Pd-silica materials has been tested in Suzuki-Miyaura C-C coupling reactions observing moderate conversion rates in the reactions of 3-bromoanisole with 4-carboxyphenylboronic acid and 2-bromopyridine with 4-carboxyphenylboronic acid. In addition, the synthesized materials showed a good degree of recyclability, being catalytically active in five consecutive catalytic tests. Finally, in order to evaluate the cytotoxicity of the synthesized materials, in vitro tests against five different human cancer cell lines have been carried out, observing high cytotoxic activities of the hybrid systems comparable if not somewhat higher to other systems based on metal complexes supported on mesoporous silicas described previously in the literature. To the best of our knowledge the cytotoxic study reported here represents the first evaluation of the anticancer action of supported palladium nanoparticles in human cancer cells.