Improving Polymeric Structures with Hirshfeld Atom Refinement: A Study on MOFs and COFs

Many metal–organic frameworks (MOFs) and covalent organic frameworks (COFs) can form crystals amenable to single-crystal X-ray diffraction analysis. It makes them suitable for Hirshfeld atom refinement (HAR) which has a well-established advantage over the Independent Atom Model in terms of the determination of hydrogen atom positions in the case of molecular crystals. However, up until now, the application of HAR to crystals of polymeric compounds such as MOFs and COFs has not been thoroughly investigated. This study of X-ray data sets collected for 20 MOFs, COFs and other coordination polymers is designed to provide an extensive assessment of two different implementations of HAR with respect to hydrogen positions and refinement statistics, given varying data quality.