Directing Molecular Weaving of Covalent Organic Frameworks and Their Dimensionality by Angular Control

Although reticular chemistry has commonly utilized mutually embracing tetrahedral metal complexes as crossing points to generate three-dimensional molecularly woven structures, weaving in two dimensions remains largely unexplored. We report a new strategy to access 2D woven COFs by controlling the angle of the usually linear linker, resulting in the successful synthesis of a 2D woven pattern based on chain-link fence. The synthesis was accomplished by linking aldehyde-functionalized copper(I) bisphenanthroline complexes with bent 4,4'-oxydianiline building units. This results in the formation of a crystalline solid, termed COF-523-Cu, whose structure was characterized by spectroscopic techniques and electron and X-ray diffraction techniques to reveal a molecularly woven, twofold-interpenetrated chain-link fence. The present work significantly advances the concept of molecular weaving and its practice in the design of complex chemical structures.