From Assembly to Application: A Comprehensive Review of Metal-Hydrogen-Bonded Organic Frameworks.

Metal-hydrogen-bonded organic frameworks (M-HOFs) have emerged as novel crystalline porous materials that integrate robust metal coordination units with extensive hydrogen-bonded networks, enabling architectures that offer both structural stability and tunable functionality. Extensive hydrogen bonding confers structural integrity, while incorporation of metal ions enhances chemical and thermal stability and introduces catalytic and sensing properties. Their tunable porosity, diverse topologies, and mild synthesis conditions render them highly desirable for applications in chemical separation, gas storage, catalysis/photocatalysis, and environmental monitoring. This review provides a comprehensive overview of recent advances in the structural elucidation, and functional development of M-HOFs. The self-assembly of these frameworks governed by the careful selection of metal centers and organic linkers critically determines pore architecture, topology, and overall stability. Within this context, hydrogen-bonding interactions serve as essential supramolecular forces that direct and stabilize framework formation. Structural investigations have revealed the remarkable adaptability of hydrogen-bonding networks, which can be finely tuned to modulate pore dimensions, enhance framework robustness, and introduce tailored functionalities. These tunable structural features directly influence the performance of M-HOFs, enabling their effective use in a wide range of practical applications. M-HOFs have already demonstrated strong potential in (photo) catalysis, adsorption, sensing, and drug delivery, underscoring their versatility as next-generation porous materials. Finally, key opportunities are highlighted in environmental remediation, clean energy technologies, and advanced functional applications.