Visualizing the Dynamics of Temperature- and Solvent-Responsive Soft Crystals

We demonstrate that three flexible MOFs termed FJI‐H11‐R (FJI‐H=Hong's group in Fujian Institute of Research on the Structure of Matter, R=Me, Et, iPr) can reversibly respond to temperature and solvents via structural transformations, which can be visualized by in situ single‐crystal X‐ray snapshot analyses. FJI‐H11‐R exhibit colossal anisotropic thermal expansion, with a record‐high uniaxial positive thermal‐expansion coefficient of 653.2×10−6 K−1 observed in FJI‐H11‐Me. Additionally, large c‐axial shrinkage of 32.4 % is also observed during desolvation. The stimuli‐responsive mechanism reveals the structural evolutions are related to the rotations and deformations of the organic linkers. See the shrink: A record high uniaxial positive thermal expansion coefficient of 653.2×10−6 K−1 and large c‐axial shrinkage of 32.4 %, is found for metal–organic framework (MOF) temperature‐ and solvent‐responsive soft crystals. The dynamic process can both be visualized by in situ single‐crystal X‐ray snapshot analyses. The stimuli‐responsive mechanism results from rotations and deformations of the organic linkers.