Pd–PEPPSI Complex Integrated into Hyper‐Crosslinked Polymer: A Highly Stable and Reusable Catalyst for Heterogeneous C–C Coupling Reactions

Catalyst deactivation due to aggregation or leaching of active metal species remains a major challenge in heterogeneous catalysis. In this study, a homogeneous Pd–PEPPSI (Pyridine‐Enhanced Pre‐catalyst Preparation, Stabilization, and Initiation) complex was transformed into a single‐site heterogeneous catalyst by incorporating it into a hyper‐crosslinked polymer (HCP) via a one‐step direct knitting strategy. In the Pd–PEPPSI complex, 3‐chloropyridine acts as an ancillary ligand, stabilizing the palladium center and facilitating oxidative addition in C─C coupling reactions, while the N ‐heterocyclic carbene (NHC) serves as the functional ligand. The HCP's hierarchical pore structure and high surface area enhance catalyst recyclability and reduce metal leaching. The HCP‐Pd–PEPPSI‐3 catalyst efficiently catalyzed Suzuki–Miyaura cross‐coupling reactions of various aryl halides and arylboronic acids at a Pd loading of 0.10 mol%, achieving a 99% yield with a turnover frequency (TOF) of 1.23 × 10⁴ h −1 . Additionally, it achieved up to 98% yield in the Mizoroki–Heck reaction at the same Pd loading. The catalyst maintained a 90% yield after 10 cycles, demonstrating excellent recyclability. This strategy prevents Pd leaching and aggregation, making HCP‐Pd–PEPPSI‐3 a versatile and sustainable catalyst for Pd‐catalyzed reactions.