Topological Derivative Strategy for Large-Pore Three-Dimensional Covalent Organic Frameworks

The pursuit of three-dimensional covalent organic frameworks (3D COFs) with ultralarge pores faces fundamental challenges from structural interpenetration. We address this limitation through a topology-driven design strategy that transforms edge-transitive scu nets into two distinct derivative frameworks─ mmm and jcg ─via symmetry-controlled monomer selection. This approach yields contrasting pore evolution behaviors: while mmm series COFs (JUC-693 to JUC-695) show unpredictable pore size fluctuations (2.6 → 3.9 → 1.2 nm) due to complex interpenetration patterns, jcg series frameworks (JUC-696 to JUC-698) exhibit controlled expansion up to a record of 5.1 nm pore diameter in JUC-698. Comprehensive characterization, including macromolecular encapsulation studies with vitamin B12 and myoglobin, confirms the structural integrity and accessibility of these engineered pores. Our findings establish topology-directed design as a powerful tool for overcoming interpenetration barriers in porous materials development.