Within the first half of MAGNIFY, we have set up tools to study both synthesis and phase transitions of MOFs from the Zeolitic-Imidazolate Framework (ZIF) family. ZIFs resemble zeolites in that their metal-ligand-metal angle is similar to the T-O-T zeolite angle, most of them are very stable and promising for many industrial and environmental applications. In order to model both the early polymerization events of self-assembly as well as nucleation and growth as a whole, we needed to go from the atom scale to a scale where the minimal unit are molecules or molecular fragments. We already had a partially reactive force field for the atomistic simulations,[J. Chem. Phys., 157, 184502 (2022)] so we developed coarse grained (CG) models[J. Chem. Phys., 158, 194107 (2023); J. Chem. Phys., 160, 094115 (2024)]. The development of CG models for ZIFs was an important result by itself, as this was the first time that a systematic exploration of CG strategies was done for MOFs. Moreover, it was also the first time that the three strategies we tested were applied to model porous materials, so we had to tackle new challenges that had never been encountered by other researchers before.
With these tools at hand, we embarked in the study of several important reactive processes of ZIFs, including the mechanisms of the early stages of the nucleation of ZIF-8,[ J. Chem. Phys., 157, 184502 (2022)] the phase transformation between ZIF-4 and its amorphous ambient pressure polymorph,[ J. Mater. Chem. A, 12, 4572 - 4582 (2024)], and the first stages of its self-assembly.[E. Méndez, R. Semino; Chem. Sci.; DOI: 10.1039/D5SC00807G (2025)] These works implied both important methodological developments, including the creation of a neural network capable of identifying a polymorph at the atomic level and the implementation of metadynamics schemes, and have also helped us answering important questions such as: what are the microscopic degrees of freedom that drive phase transformations of ZIFs? What is the mechanism of such phase transformations? Is early nucleation more or less favorable than late growth? Are there differences in the growth mechanisms of different polymorphs at the molecular level? These questions, among others, cannot be fully addressed experimentally. Another very interesting result we had, was that we could predict the place of ZIF-4-cp into the ZIFs phase diagram, [J. Mater. Chem. A, 12, 31108 - 31115 (2024)] which has been elusive to experimental measurement up to the moment of this writing.
