An in situ investigation of the water-induced phase transformation of UTSA-74 to MOF-74(Zn)

Abstract

We report the water-induced transformation of the [Zn2(dobdc)] (dobdc = 2,5-dioxidobenzene-1,4-dicarboxylate) metal-organic framework UTSA-74 to its polymorph MOF-74(Zn), contrary to a previous report on the stability of UTSA-74 under such conditions. This dissolution-recrystallization process was investigated using time-resolved in situ X-ray diffraction and kinetically analyzed using the Gualtieri crystallization model.

Investigation of the Kinetic Stabilization of a Ce4+‐based MOF by in‐situ Powder X‐ray Diffraction

“…The MOF intermediate is observed for shorter times at higher temperature and its decomposition is accelerated as well with increasing temperature. We have recently observed in another study that re‐dissolution of the framework could be fitted very well with an exponential decay function . However, in the case of Ce‐DUT‐67‐PZDC the dissolution cannot be modeled by exponential decay since it is apparently proceeding faster with increasingly linear shape.…”

“…In addition, the crystallization kinetics can be assessed and compared at different temperatures or using different heating methods . Moreover, such techniques can be employed to investigate more complex reactions like the exchange of solvent molecules coordinated to metal ions, the adsorption of guest molecules into flexible frameworks, and the formation of a MOF from a less stable precursor MOF . It was also demonstrated by in‐situ PXRD that MOF themselves can be comparably short‐lived, intermediate precursors which re‐dissolve to eventually form dense compounds , …”

Green Synthesis of a New Al‐MOF Based on the Aliphatic Linker Mesaconic Acid: Structure, Properties and In Situ Crystallisation Studies of Al‐MIL‐68‐Mes

“…Especially the occurrence of the X‐ray amorphous by‐product could limit the validity of the employed theories. However, based on the observations for Fe‐MIL‐89 [Fe 3 O(CH 3 OH) 3 [O 2 C‐(CH) 4 ‐CO 2 ] 3 Cl], and MOF‐74 which form from intermediates via re‐dissolution and crystallization, a similar mechanism seems to be likely in our case. Nevertheless, this kinetic analysis was predominantly carried out to evaluate if and to which extent it can be applied to such slurry based systems at all.…”

Multiparameter High-Throughput and in Situ X-ray Diffraction Study of Six New Bismuth Sulfonatocarboxylates: Discovery, Phase Transformation, and Reaction Trends

“…A detailed description of the set-up can be found in references. [40][41][42] CCDC entries 1837217-1837222 for compounds 1 -6 contain the supplementary crystallographic data for this paper. These data can be obtained free of charge from The Cambridge Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_request/cif.…”

“…This reactor system offers the advantages of precise and remote-controlled heating and injection of up to two solvents or solutions or one solid. [40][41][42] A summary of the reaction parameters for the in situ study is given in Table 1. Reactions were carried out at 120, 150 and 180 °C using the following reaction compositions: metal to H4DSNDC to HNO3 = 2:2:0, 2:4:5, 4:4:5 and 4:4:0.…”