Latent asymmetry of gate opening and closing in a flexible MOF probed by time-resolved in-situ XRD

Abstract

Time-resolved in-situ X-ray diffraction reveals a latent asymmetry in the gate-type transitions of the flexible metal-organic framework ELM-11. The gate-closing pathways for CO₂ and n-butane are highly asymmetric and distinct from their gate-opening processes. During CO₂ desorption, a unique intermediate phase is formed. The gate closing for n-butane is more complex, involving a continuous structural deformation followed by a sequential, discontinuous transition. This work shows that high-resolution structural mapping across the entire pressure range is crucial for uncovering the true complexity of flexible materials.