The thermal stabilities of MOF-5 and its methyl-modified structures were investigated using molecular dynamics (MD) simulations. Implementing reactive force field (ReaxFF) enabled the modeling of bond breakage during the high-temperature decomposition process. Thermal decomposition was initialized by the breakage of the weak coordination bond, followed by structural collapse at elevated temperatures. Deterioration of the thermal stability upon functionalization of the linker with methyl groups was observed and all the structures showed a negative thermal expansion behavior with the negative thermal trend augmented with increasing the number of methyl functional groups on the linker. The present work sheds light on the role that linker motion plays in lowering the thermal stability and also shows that the selection of a rigid linker can help improve the thermal stability of metal−organic frameworks for hightemperature applications.

Amorphous metal–organic frameworks (MOFs) have the potential for applications such as controlled drug delivery and hazardous material encapsulation. Moreover, their distinct mechanical properties may facilitate fabrication of industrial-scale adsorbents for gas uptake applications. However, the dense amorphous phase has less capacity for gas adsorption compared to its parent crystalline structure because for the majority of MOFs, amorphization drops their accessible porosity and negatively affects their gas adsorption capability. In the present computational study, we show that for some MOFs with nonaccessible regions, the deformed (partially amorphized) structure can compete with its crystalline counterpart for the surface area available for gas uptake. Our reactive molecular dynamics simulations show that more than 40% increase in the accessible surface area can be attained upon shear deformation for some of the MOFs that were investigated. Overall, we demonstrate that for some MOFs, amorphization can bring favorable features and improve their surface area characteristics by opening up the nonaccessible regions during the amorphization process.

Many metal−organic frameworks (MOFs) suffer from stability issues as they can be easily amorphized from various external stimuli. In particular, it is common to observe structural collapse during the activation process of removing the synthesis solvent. In this study, we conduct high-throughput computational analysis that focuses on the activation status of MOFs that possess copper paddlewheel metal nodes. From the analysis, various mechanical properties (e.g., bulk, Young's, and shear moduli) were found to be good predictors for collapse. Furthermore, we have identified anomaly MOFs with good mechanical stability that were previously reported to collapse. Accordingly, the activation process was reattempted with improved techniques, and one of these MOFs was successfully activated.

Many metal-organic frameworks (MOFs) suffer from stability issues as they can be easily amorphized from various external stimuli. In particular, it is common to observe structural collapse during the activation process of removing the synthesis solvent. In this study, we conduct high-throughput computational analysis that focuses on activation status of MOFs that possess copper paddlewheel metal nodes. From the analysis, various mechanical properties (e.g. bulk, young, and shear moduli) were found to be good predictors for collapse. Furthermore, we have identified anomalies MOFs with good mechanical stability that were previously reported to collapse. Accordingly, the activation process was re-attempted with improved techniques, and these MOFs were successfully activated.