In situ solid-state NMR and XRD investigations of structural transformations in crystalline porous solids

In-situ measurement techniques have significantly gained in importance during the last decades, as they have the potential to reveal detailed and realistic insights into chemical reactions. Also for complex processes in solid phases as adsorption or structural transformations in-situ investigations are the method of choice to receive information at molecular level.
In this work a novel designed 4.0 mm wide-bore probe is presented that enables in-situ solid-state NMR measurements under continuous flow conditions and at elevated temperature while the rotor is spinning at the magic angle. The special feature of the probe is a very fast, selective and uniform heating of the sample in the rotor which is realized by lasers. The operation and working principle of the probe is demonstrated with oberservations of structural transformations in porous crystalline solids. In combination with in-situ XRD studies the application of the probe allowed for new insights into the recrystallization kinetics and mechanism of VPI-5 to AlPO4-8 and the breathing behaviour of MOFs with MIL-53 type topolgy.