Fig. 1
Temperature-induced breathing of a flexible MOF. The definition of the blue and green symbols is indicated in the top left panel. a Two (meta)stable phases of MIL-53(Al). b Thermo-responsive behavior of MIL-53(Al) as measured by experiment. The system switches as a function of temperature between the np and lp phase with a hysteresis loop. Different transition regimes are indicated with arrows (see main text). The gray shaded areas correspond to the experimentally measured transition regions7. c Hypothetical Helmholtz free energy curves as a function of volume at different temperatures (T1, T2, T3, T4, T5) as an explanation for the observed experimental behavior. d Hypothetical evolution of the Helmholtz free energy for the np and lp phase as a function of temperature. The gray shaded areas correspond to the experimentally measured transition regions7
