Cage-based hydrogen-bonded organic frameworks: a systematic review

Hydrogen-bonded organic framework (HOF) materials represent a novel category of porous materials that have attracted considerable attention owing to their mild synthesis conditions, self-healing capabilities, and recyclability. Molecular cages serve as critical components in supramolecular and host–guest chemistry. Because of their distinctive structural characteristics, HOFs offer unique advantages in heterogeneous catalysis, molecular recognition, and proton transfer processes. The integration of functionalized molecular cages with HOFs results in the formation of cage-based HOFs (Cage-HOFs). These materials possess various crystal-stacking patterns and abundant hydrogen bonds, offering promising opportunities for the development of advanced functional materials. This synergistic combination not only introduces innovative approaches for material design and functionalization but also expands the frontiers of materials science research. This review provides a comprehensive overview of the historical progress of Cage-HOFs, elucidates their structural classification and synthetic strategies, and meticulously evaluates recent developments in their applications in energy, environmental science, and catalysis. Moreover, it provides a critical assessment of the potential opportunities and challenges associated with the future advancement of Cage-HOFs, aiming to establish theoretical foundations and strategic directions for their eventual industrial applications.