Chiral supramolecular 2D halogen-bonded organic frameworks constructed by post-synthetic modified cross-linking strategy

The development of preparation methods for XOFs, as a new class of organic frameworks, plays a crucial role in shaping their structures, functions, and potential applications. In this study, we presented the construction of chiral supramolecular 2D halogen-bonded organic frameworks (XOFs) through a post-synthetic modification strategy. A linear halogen-bonded organic polymer (XOP), XOP-DPBA , decorated with aldehyde groups, was initially prepared to validate the feasibility of post-synthetic modification for XOF construction and functionalization. XOP-DPBA exhibited excellent reactivity with amines, forming imine bonds. By utilizing this reactivity, a series of cross-linked 2D XOFs were efficiently prepared through post-synthetic modified cross-linking reactions. Furthermore, we successfully introduced chiral α/β-cyclodextrins (α/β-CD) into the XOF skeletons via host-guest interactions, resulting in the fabrication of chiral supramolecular 2D XOFs. These chiral XOFs displayed the induced circular dichroism (ICD) signals and assembled them into helical fibers. The post-synthetic modification strategy demonstrated its versatility and simplicity for the construction and functionalization of XOFs.