Synthesis of Crystalline Metallated Bipyridine COFs from Amorphous Gels for Enhanced Gas Storage and Electrocatalysis.

Bipyridine-functionalized covalent organic frameworks (Bpy-COFs) possess attractive physicochemical properties that have garnered significant research interest. Subsequent metallization of these frameworks further enhances their potential for diverse applications. However, conventional synthetic routes for Bpy-COFs often suffer from limited crystallinity due to the twisted moiety. Additionally, post-synthetic metallated Bpy-COFs frequently compromise their porosity. To address these critical limitations, a facile and novel strategy is reported for the direct preparation of crystalline metallated Bpy-COFs from amorphous Bpy-covalent organic gels (COGs), employing metal ions in concert with carbon dioxide (CO2) subcritical fluid as a dynamic modulator. The resulting COF aerogels exhibit high porosity and dispersed metal sites, contrasting sharply with materials derived from traditional methods, and demonstrate substantially enhanced performance in hydrogen storage and the oxygen evolution reaction. This breakthrough in establishing a bridge between amorphous COGs and crystalline COFs not only broadens the synthetic accessibility of functional porous materials but also opens new avenues for the rational design of advanced crystalline frameworks with tailored functionalities.