Green Reconstruction of MIL-100 (Fe) in Water for High Crystallinity and Enhanced Guest Encapsulation

MIL‑100 (Fe) is a highly porous and environmentally friendly metal‑organic framework (MOF) considered as a promising carrier for drug delivery, and for gas separation and capture applications. However, this functional material suffers from elaborated and toxic synthesis that may hinder its biomedical use and large‑scale production to afford commercial applications. Herein, we report a ‘green’ mechanochemical water immersion approach to yield highly crystalline MIL‑100 (Fe) material. Subsequently, we have harnessed this strategy for facile fabrication of guest@MOF composite systems, comprising (guests) 5‑fluorouracil, caffeine, or aspirin encapsulated in the pores of (host) MIL‑100 (Fe). Inelastic neutron scattering was uniquely used to probe the guest‑host interactions arising from pore confinement of the drug molecules, giving additional insights into the reconstruction mechanism. Our results pave the way to the green production of MIL‑type materials and bespoke guest-encapsulated composites for biotechnological applications.