Submicrospheres as both a template and the catalyst source. silica submicro-reactor dotted with palladium nanoparticles as catalysts

Formation of the monodisperse submicrospheres consisting of ionic palladium(II) complexes, [(Me₄en)Pd(L)]₂(X)₄ (Me₄en = N,N,N',N'-tetramethylethylenediamine; L = bis(4-(4-pyridylcarboxyl)phenyl)methane; X- = BF₄ ^- and ClO₄ ^-), has been carried out without any templates or additives. The submicrospheres were coated with silicates, and then calcined in air at 550 °C for 1 h, to efficiently form hollow-spherical SiO₂ submicro-reactors dotted with palladium(0) nanoparticles (PdNPs). That is, the submicrospheres act as both a template and a source of the palladium metal nanoparticles. The submicro-reactors containing nano-catalysts have been characterized by means of SEM, TEM, and XPS. Notably, the reactors were proved to be very effective for Suzuki-Miyaura cross-coupling and hydrogenation reactions.