Sustainable Synthesis of Palladium-Immobilized Covalent Organic Frameworks: A One-step Sonochemical Strategy

Abstract

The rapid and environmentally benign synthesis of metal-immobilized covalent organic frameworks (metal/COFs) for heterogeneous catalysis is a pervasive challenge, as the mainstream synthesis is exceedingly time-consuming (up to four days) and demands the use of hazardous solvents. Herein, we describe a sustainable and efficient one-step sonochemical strategy for constructing diverse palladium (II)-immobilized COFs (Pd(II)/COFs). By merging the sonochemistry-assisted COF synthesis and in situ Pd (II) immobilization into a single step, this strategy enables the rapid formation of Pd(II)/COF hybrids within an hour under ambient conditions using water as the solvent. Notably, gram-scale synthesis of Pd(II)/COFs is achievable. The resulting Pd(II)/COFs exhibit superb crystallinity and high surface area, leading to remarkable activity, excellent functionality tolerance, and high recyclability for the Suzuki–Miyaura cross-coupling reaction of aryl bromides and arylboronic acids at room temperature. This one-step sonochemical strategy effectively addresses the long-lasting limitations of traditional multistep synthesis, paving a fast and sustainable avenue to diversified metal/COF hybrids for heterogeneous catalysis and potentially other applications.