Machine Learning and Molecular Simulations Reveal Mechanisms of ZIFs Polymorph Selection

Fuente: arXiv
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Main Authors: Méndez, Emilio, Semino, Rocio
Format: Preprint
Published: 2026
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author Méndez, Emilio
Semino, Rocio
author_facet Méndez, Emilio
Semino, Rocio
contents Zn(imidazolate)$_2$ metal-organic frameworks (MOFs) exhibit a remarkable degree of polymorphism. Because of their promising industrial applications, many research groups have investigated phase transitions, phase diagram and relative stability of these polymorphs. There is now wide consensus in the research community that these MOFs are solvothermally formed via non-classical nucleation mechanisms, in which pre-nucleation clusters are first formed, followed by an intermediate amorphous structure that subsequently reorganizes to yield the final crystalline MOF. However, no study up to date has uncovered which part of the synthesis process determines the final polymorph obtained. In this work, path collective variable metadynamics simulations performed with a partially reactive force field give insights into mechanistic and thermodynamic aspects of the self-assembly of these MOFs. Databases of transient and intermediate synthesis structures are built from the simulations. By developing and applying neural network classifiers over these databases, it is found that both pre-nucleation clusters and the amorphous intermediate structures are polymorph-dependent. These results suggest that polymorph selection happens as early as the pre-nucleation cluster stage.
format Preprint
id arxiv_https___arxiv_org_abs_2604_28106
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Machine Learning and Molecular Simulations Reveal Mechanisms of ZIFs Polymorph Selection
Méndez, Emilio
Semino, Rocio
Materials Science
Chemical Physics
Zn(imidazolate)$_2$ metal-organic frameworks (MOFs) exhibit a remarkable degree of polymorphism. Because of their promising industrial applications, many research groups have investigated phase transitions, phase diagram and relative stability of these polymorphs. There is now wide consensus in the research community that these MOFs are solvothermally formed via non-classical nucleation mechanisms, in which pre-nucleation clusters are first formed, followed by an intermediate amorphous structure that subsequently reorganizes to yield the final crystalline MOF. However, no study up to date has uncovered which part of the synthesis process determines the final polymorph obtained. In this work, path collective variable metadynamics simulations performed with a partially reactive force field give insights into mechanistic and thermodynamic aspects of the self-assembly of these MOFs. Databases of transient and intermediate synthesis structures are built from the simulations. By developing and applying neural network classifiers over these databases, it is found that both pre-nucleation clusters and the amorphous intermediate structures are polymorph-dependent. These results suggest that polymorph selection happens as early as the pre-nucleation cluster stage.
title Machine Learning and Molecular Simulations Reveal Mechanisms of ZIFs Polymorph Selection
topic Materials Science
Chemical Physics
url https://arxiv.org/abs/2604.28106