Ionic covalent organic frameworks for highly effective catalysis

As an emerging class of crystalline porous materials, covalent organic frameworks (COFs) have been widely used as catalysts or catalyst supports. Flexible regulation of the pores and easy introduction of functional active sites onto the skeleton of COFs make them promising platforms for many catalysis applications. However, only a single function is generally observed in these COFs. Herein, we synthesized a negatively charged ionic COF (I-COF) and successfully incorporated functionalized counter ions, that is, metallic Mn2+ and a coordination complex of manganese(II) bipyridine complexes ([Mn(bpy)2]2+), via a simple ion exchange process. The resulting I-COFs can act as effective heterogeneous catalysts for epoxidation reactions. We envisage that with this type of ionic architecture, a variety of other functional cations could be exchanged into the frameworks, thus making the COF a versatile platform for different applications.