There is an increasing interest in the amorphous states of metal−organic frameworks (MOFs) and porous coordination polymers, which can be produced by pressureinduced amorphization, temperature-induced amorphization, melt−quenching, ball milling, irradiation, etc. They can exhibit useful physical and chemical properties, distinct from those achievable in the crystalline states, along with greater ease of processing, and intrinsic advantages over crystals and powders, such as high transparency and mechanical robustness. However, these amorphous states are particularly challenging to characterize, and the determination of their framework structure at the microscopic scale is difficult, with only indirect structural information available from diffraction experiments. In this Perspective, we review and compare the existing methodologies available for the determination of microscopic models of amorphous MOFs, based on both experimental data and simulation methods. In particular, we present the atomistic models that can be obtained using Reverse Monte Carlo (RMC) methods, Continuous Random Networks (CRN), classical and ab initio molecular dynamics, reactive force fields, and simulated assembly/polymerization algorithms.

While amorphous metal–organic frameworks form an emerging class of materials of growing interest, their structural characterization remains experimentally and computationally challenging. Out of the many molecular simulation methods that exist to model these disordered materials, one strategy consists in simulating the phase transition from a crystalline MOF to the amorphous state using molecular dynamics. ReaxFF reactive force fields have been proposed for this purpose in several studies to generate models of zeolitic imidazolate framework glasses by melt quenching. In this work, we investigate the accuracy and reliability of this approach by reproducing the published procedures and comparing the structure of the resulting glasses to other data, including ab initio modeling, in detail. We find that the in silico melt-quench procedure is extremely sensitive to the choice of methodology and parameters and suggest adaptations to improve the scheme. We also show that the glass models generated with ReaxFF are markedly different from their ab initio counterparts, as well as known experimental characteristics, and feature an unphysical description of the local coordination environment, which in turn affects the medium-range and bulk properties.