Density Functional Theory (DFT) plays a key role in the computational study of Metal Organic Frameworks (MOFs) for various applications. To assess the performance of DFT for predicting properties a MOF-specific benchmarking study of DFT functionals (M06L, PBE, PW91, PBE-D2, PBE-D3, and vdw-DF2) were performed. To achieve this task, we compiled a test set of chemically and topologically diverse MOFs with high accuracy experimentally derived crystallographic structures. Specifically, we have studied the variance in performance of DFT functionals for MOF structural parameters, elastic properties, and atomic point charges. We found that while there are differences in the magnitude of the properties predicted by the various functionals, these discrepancies are small compared the accuracy necessary for most practical applications. Motivated by these observations, we have used the PBE functional to assign atomic point charges derived from periodic DFT electronic structure calculations for over 2,000 unique experimentally synthesized MOFs. These DFT-derived atomic point charges were compared to semi-empirical group contribution and charge equilibration methods for assigning charges. These charges have been made publically available as part of the CoRE MOF database. As an example of using these charges, we examined each MOF for usefulness in the adsorptive removal of tert-butyl mercaptan (TBM) from natural gas. Monte Carlo simulations revealed many candidate MOF structures with high selectivity for TBM over methane and high TBM capacity. We anticipate that this public dataset of atomic point charges for MOFs will facilitate high-throughput screening for a wide variety of applications where electrostatic interactions must be considered.

Using high-quality, atomic point charges for metal-organic frameworks to enable high-throughput screening of materials for contaminant removal from methane

251st National Meeting (2016)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.