Utilizing a Pickering Emulsion for Suzuki-Miyaura Coupling with an Amine-Coordinated Pd Catalyst

Abstract

The Suzuki-Miyaura coupling reaction catalyzed by transition metals and their complexes for the construction of C-C bonds has been widely used in many fields. However, there have been problems such as difficulty in recycling homogeneous catalysts and low transfer efficiency of heterogeneous catalysts in reactions. To address above problems, an aminecoordinated Pd catalyst (GO-DAP-PdCl2) was prepared by coordination PdCl2 on graphene oxide (GO) with solid-loaded amine ligand (2,6-diaminopyridine, DAP) on the surface. Among which the amphiphilic Pickering emulsion catalyst (GO-DAP) could form stable O/W emulsions, where the hydrophilic GO sheets and hydrophobic DAP moieties were anchored at the oil-water interface to provide a high interfacial area for the reaction, and significantly reduce the mass-transfer resistance between the two phases. In the Suzuki-Miyaura coupling reaction, the coordination Pd-based Pickering emulsion catalyst (GO-DAP-PdCl2) showed excellent catalytic performance, the conversion rate of iodobenzene reaches up to 95%, the TOF up to 14100 h -1 , the conversion still up to 85% after 6 cycles, and the catalyst also exhibits good substrate suitability.