Solvent- and HF-free synthesis of flexible chromium-based MIL-53 and MIL-88B

Abstract

Flexible chromium-based metal-organic frameworks (MOFs) possess unique structural properties on account of their intriguing breathing effect. However, their synthesis often requires the use of corrosive HF and bulk solvents. Herein, we report a facile 2-step synthesis of flexible MIL-53 (Cr) and MIL-88B (Cr) without using solvents and HF acid modulator. This methodology was highly selective based on the type of metal precursors used, giving the two MOFs separately under similar synthetic procedure. The synthesized MIL-53 (Cr) and MIL-88B (Cr) were fully characterized by multiple techniques to ensure their high quality. This work highlights a useful strategy to be adopted for future scale-up production of flexible chromium-based MOFs.