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.