Reticulating 1D Ribbons into 2D Covalent Organic Frameworks by Imine and Imide Linkages

The design and synthesis of 2D and 3D crystalline covalent organic frameworks (COFs) from macromolecular and even infinite building units is largely undeveloped. Here, we report a strategy to link molecules and 1D ribbons into 2D cystalline frameworks. Triangular, tris(4-aminophenyl)amine (TAA), and square, 1,3,6,8-tetrakis(p-formylphenyl)pyrene (TFPPy), organic building units are joined substoichiometrically by imine linkages to produce 1D ribbons, termed COF-76, bearing free amines, which are then used to link the ribbons into 2D frameworks COF-77 and COF-78. In addition to this stepwise approach, we also demonstrate an in situ synthesis of these COFs. We believe our ability to link infinite building blocks, such as the ribbons of COF-76, into higher dimensionality COFs, paves the way to covalent frameworks composed of hierachical chemical structures.