Coarse-grained modeling of zeolitic imidazolate framework-8 using MARTINI force fields.

Area of Science:

• Materials Science
• Computational Chemistry
• Chemical Engineering

Background:

• Metal-organic frameworks (MOFs) are advanced porous materials with diverse applications.
• Coarse-grained (CG) molecular modeling offers computational efficiency for large systems like MOFs.
• The MARTINI force field is a widely used CG method, but its applicability to MOFs requires validation.

Purpose of the Study:

• To evaluate the MARTINI particle-based coarse-graining approach for modeling the ZIF-8 metal-organic framework.
• To assess the accuracy of MARTINI in predicting structural and mechanical properties of ZIF-8.
• To investigate the performance of different MARTINI versions and parameterizations for MOF simulations.

Main Methods:

• Molecular dynamics (MD) simulations using various MARTINI force field versions (e.g., MARTINI 2.0, 3.0).
• Modeling of ZIF-8 structure, lattice parameters, thermal expansion, and elastic constants.
• Analysis of amorphization, swing effect, and host-guest interactions.

Main Results:

• MARTINI force fields generally capture ZIF-8 structure well, except for less coarse MARTINI 2.0 models.
• MARTINI 2.0 models provide more accurate elastic constants (C11, C12) than MARTINI 3.0.
• None of the tested CG models reproduced amorphization or the swing effect in MD simulations.

Conclusions:

• The MARTINI force field shows promise for simulating MOF structures but requires refinement for dynamic properties.
• Accurate Lennard-Jones (LJ) parametrization is essential for modeling MOF-guest and MOF-MOF interactions.
• Further development of CG models is needed to capture complex MOF phenomena like amorphization and the swing effect.