Nanoparticle-Mediated Synthesis of Single-Crystal Covalent Organic Frameworks of Uniform Size and Shape

Here, we show that simply adding silica nanoparticles (SiNPs) to a conventional solvothermal synthesis directs imine-based COFs (e.g., COF-300) to grow into monodispersed, polyhedral single-crystal microparticles. Our experiments suggest dual functions of these nanoparticles.

They promote burst nucleation of COFs via monomer adsorption and, then, by adhering to the crystal surface, prevent crystal aggregation and nonclassical crystallization pathways. This nanoparticle-mediated strategy is compatible with common small-molecule modulation to tune COF morphologies and shapes while maintaining low size dispersity. The method also extends to other three-dimensional (3D) imine COFs, such as LZU-111 and LZU-79.