In Situ Infrared Spectroscopic and Gravimetric Characterisation of the Solvent Removal and Dehydroxylation of the Metal Organic Frameworks UiO-66 and UiO-67

Herein, the desolvation, dehydroxylation and rehydroxylation of the metal organic frameworks UiO-66 and -67 are followed by in situ DRIFTS and TG-DSC. The spectra recorded on UiO-66 feature multiple bands corresponding to chemically inequivalent isolated hydroxyl groups, whereas UiO-67 has the expected single mu(3)-OH band from the Zr6O4(OH)(4) cornerstone. Complete rehydration is demonstrated on both materials. Based on further experimental insights, hypotheses are given to explain the observed differences between UiO-66 and -67. Quantum chemical calculations are employed in order to deduce the feasibility of one possible explanation for the observed behaviour on UiO-66.