Incorporation of Ligand Charge and Metal Oxidation State Considerations into the Computational Solvent Removal and Activation of Experimental Crystal Structures Preceding Molecular Simulation

Efficient computational screenings are integral to materials discovery in highly sought-after gas adsorption and storage applications, such as CO₂ capture. Preprocessing techniques have been developed to render experimental crystal structures suitable for molecular simulations by mimicking experimental activation protocols, particularly residual solvent removal. Current accounts examining these preprocessed materials databases indicate the presence of assorted structural errors introduced by solvent removal and preprocessing, including improper elimination of charge-balancing ions and ligands. Here, we address the need for a reliable experimental crystal structure preprocessing protocol by introducing a novel solvent removal method, which we call SAMOSA, that is informed by systematic ligand charge and metal oxidation state calculations. A robust set of solvent removal criteria is outlined, which identifies solvent molecules and counterions without predefined molecule lists or significant reliance on experimental chemical information. Validation results against popular metal-organic framework (MOF) databases suggest that this method observes significant performance improvements regarding the retention of charged ligands and recognition of charged frameworks. SAMOSA enhances structure fidelity with respect to the original material as-synthesized, thereby representing a powerful tool in computational materials database curation and preprocessing for molecular simulation. The source code is accessible at https://github.com/uowoolab/SAMOSA.