Résumé
An alternative activation method was developed to stabilize the Metal Organic Framework MIL-47(V) material in the VIII oxidation state. This solid and the oxidized forms were investigated by in situ infrared and Raman spectroscopies, XRD and Complex Impedance Spectroscopy. Unlike MIL-47(VIV), MIL-47(VIII) is a flexible structure which presents µ2-hydroxyl groups acting as preferential adsorption sites for H2O or CO2. The modulation of the oxidation state of the metal center of this porous material leads to new intermediate porous solids with mixed oxidation states VIII/VIV. In these materials, the VIII and VIV centers seem to occur in close vicinity. However, the presence of VIV centers inhibits the flexibility to a large extent.