Generic Vitrification of Prototype Metal-Organic Frameworks Linked by Rigid Dicarboxylate Linkers

Vitrifying crystalline metal-organic frameworks (MOFs) is an emerging route to creating processable glassy materials with novel functions. However, a vast portion of MOFs, such as seminal MOF-5, are constructed from rigid aromatic dicarboxylate linkers. While essential for reticular design, these aromatic dicarboxylate linkers impart low configurational entropy, which has historically precluded the vitrification of a major portion of MOFs. Here, we report a generalizable strategy to overcome this limitation by synergistically promoting configurational degree of freedom, which combines grafting flexible side chains onto the rigid linkers, employing mixed-metal nodes, and introducing coordination modulators to tune network connectivity. This strategy is demonstrated by successfully vitrifying functionalized MOF-5 and MIL-101, producing a series of glasses with tunable properties controlled by the modulator content and metal composition. The resulting glasses exhibit promising functional properties, including high photoluminescence quantum yields, uniformity, and robustness as a host matrix for optically pumped lasers. This work establishes rational design principles for converting rigid MOFs into glassy materials, unlocking a vast library of reticular structures for the development of new functional glasses.