Construction of ionic cavities in porous aromatic frameworks for palladium immobilization and effective catalysis

Abstract

In the chemical industry, developing efficient and recyclable heterogeneous catalysts for the Suzuki–Miyaura coupling reaction is crucial for the formation of carbon–carbon bonds. In particular, enough spaces surrounding the active sites within heterogeneous catalysts are necessary for the catalysis of large-sized substrates. Herein, a strategy was proposed to construct a porous aromatic framework (PAF-282) with ionic cavities for palladium immobilization and effective Suzuki–Miyaura coupling reactions. The ionic PAFs exhibited high surface area, porous structure, and excellent hydrophilicity, and they showed excellent catalytic efficiencies for a range of substrates, including large-sized substrates. Furthermore, no palladium leaching occurred during the reactions, and PAF-282-Pd²⁺ could be easily recovered and reused several times. Notably, the turnover frequency (TOF) of PAF-282-Pd²⁺ was as high as 9700 h⁻¹.