Insights to the formation of Zr-based metal-organic frameworks from in situ powder x-ray diffraction

This study sheds light on the kinetics of crystallisation of two Zr-based metal-organic frameworks (MOFs), namely Zr6-MOF-808 and Zr6-MOF-801, using in situ powder x-ray diffraction (PXRD). Once a room temperature synthesis for the two MOFs was designed for the very small scale, a successful series of in situ PXRD experiments over the range of 10 degrees C-40 degrees C yielded high quality quantitative information on the kinetics of crystallisation for both MOFs. These findings indicate the importance of the solubility of the linker and its connectivity: while the rate of nucleation and the resulting particle size of the MOF (Zr6-MOF-801), with the less soluble and lower connected linker, was strongly temperature dependent, the growth and particle size of Zr6-MOF-808 was hardly impacted by an increase in temperature. This work highlights the importance of careful preliminary research and helps to improve future MOF synthesis design to efficiently achieve the desired particle size distribution.