ZrCl4 (1 mmol, 233 mg), H2FUM (3 mmol, 348 mg) and acetic acid (100 mmol, 5.7 mL) were placed together in a hydrothermal bomb with 20 mL of deionized water and the solution was sonicated until complete reagents dissolution. Then, the reactor was held in a thermostatic oven at 120 °C for 24 h. The obtained white solid was recovered by centrifugation, washed with water (2 × 10 mL) and acetone (1 × 10 mL) and finally dried in an oven at 80 °C. Yield: 200 mg (87%, based on zirconium). The phase identity and purity were checked through PXRD. The amount of AA present in the material was estimated through h. The obtained solids were recovered by centrifugation and washed with ethanol (2 × 5 mL), water (1 × 5 mL) and acetone (1 × 5 mL) and finally dried in an oven at 80 °C. Yield: 224 mg and 237 mg (99,99% and 99,93%, based on zirconium present in the pristine MOF-801 and using the results from ICP measurements for quantifying the metal leaching after the exchange, Table ) for PF-MOF1 and PF-MOF2, respectively. The proposed minimal formulae reported above come from quantitative 1 H-and N2 and CO2 Adsorption. All the samples were activated at 120 °C under high vacuum (10 -6 Torr)