A pillar[5]arene-based covalent organic framework with pre-encoded selective host-guest recognition.

It is highly desirable to maintain both permanent accessible pores and selective molecular recognition capability of macrocyclic cavitands in the solid state. Integration of well-defined discrete macrocyclic hosts into ordered porous polymeric frameworks (, covalent organic frameworks, COFs) represents a promising strategy to transform many supramolecular chemistry concepts and principles well established in the solution phase into the solid state, which can enable a broad range of practical applications, such as high-efficiency molecular separation, heterogeneous catalysis, and pollution remediation. However, it is still a challenging task to construct macrocycle-embedded COFs. In this work, a novel pillar[5]arene-derived () hetero-porous COF, denoted as , was rationally designed and synthesized. Featuring the unique backbone structure, exhibited selective adsorption of CH over CH and CH, as well as significantly enhanced host-guest binding interaction with paraquat, in comparison with the pillar[5]arene-free COF analog, . The present work established a new strategy for developing COFs with customizable molecular recognition/separation properties through the bottom-up "pre-porous macrocycle to porous framework" design.