Heterogeneous Catalysis by Covalent Organic Frameworks (COF): Pd(OAc)₂@COF‐300 in Cross‐Coupling Reactions

Abstract

Abstract COF‐300, an imine‐linked, crystalline, and microporous covalent organic framework, modified by coordination of Pd(OAc) 2 to its walls, afforded a hybrid material, Pd(OAc) 2 @COF‐300, which was used as an efficient heterogeneous catalyst for cross‐coupling reactions. This material showed excellent catalytic activity for the phosphine‐free Suzuki–Miyaura, Heck, and Sonogashira cross‐coupling reactions with low palladium loadings (0.1 mol % Pd). X‐ray photoelectron spectroscopy analysis of the catalyst after the reaction showed that Pd II is converted to Pd 0 , which is trapped within the COFs nanopores. This was confirmed by high‐resolution transmission electron microscopy. Moreover, promising results were obtained using Pd(OAc) 2 @COF‐300 under continuous‐flow conditions for a Suzuki–Miyaura cross‐coupling reaction.