Crystalline\nand Stable Benzofuran-Linked Covalent\nOrganic Frameworks from Irreversible Cascade Reactions

Abstract

We report the synthesis\nof crystalline two-dimensional covalent\norganic frameworks (COFs) by connecting hydroxybenzene-aldehyde and\nacetonitrile building blocks to form cyano-substituted benzofuran\nlinkages. Unlike the majority of COFs that were synthesized based\non condensation reactions, the COFs in this report are crystallized\nfrom irreversible cascade reactions involving consecutive cyanide\nmigration, ring-closure, and oxidation reactions. The irreversible\nproperty endows the COFs with high chemical stability in both acid\nand base and allows them to be postsynthetically modified to install\npredesigned functionality under harsh conditions. We highlight that\nthe functionalized COFs serve as exceptional vehicles for superprotonic\nconductions.