Supported C60-IL-PdNPs as extremely active nanocatalysts for C–C cross-coupling reactions

Abstract

A C₆₀-ionic liquid hybrid has been covalently linked to three different solid supports, namely amorphous silica, SBA-15 and Fe₂O₃@SiO₂, and the resulting materials have been employed as covalently supported ionic liquid phases (cSILP) in order to immobilize and stabilize palladium nanoparticles (PdNPs). These novel hybrid materials are based on a sort of “matryoshka” system (PdNPs@imidazolium-salt@C₆₀@support) in which the imidazolium-based moieties have not been directly linked to the surface of the support, but they are present in an octopus-like spatial arrangement on the uniformly surface-distributed fullerenes. These materials have been fully characterized and successfully employed as catalysts in C–C bond forming reactions showing, in the case of Suzuki cross-coupling, an outstanding catalytic activity both under classical heating and by irradiating with microwaves. Turn-over frequencies (TOFs) of up to 3 640 000 h⁻¹ have been achieved and the silica-based catalyst showed full recyclability even after 10 cycles.