The templating effect of the Keggin polyanion derived from phosphotungstic acid (PTA) during the synthesis of NH2-MIL-101(Al) has been investigated by means of in situSAXS/WAXS. Kinetic analysis and structural observations demonstrate that PTA acts as a nucleation site and that it stabilizes the precursor phase NH2-MOF-235(Al). Surprisingly kinetics of formation are little changed.
