Advancing the use of Voronoi–Dirichlet polyhedra to describe interactions in organic molecular crystal structures by the example of galunisertib polymorphs

Abstract

Using the method of molecular Voronoi–Dirichlet polyhedra all types of atomic interactions in ten known polymorphs of the drug galunisertib (GAL) – one of the most prolific polymorphic systems – were analyzed quantitatively in detail. It was shown that every polymorph of GAL is characterized with a unique set of intra- and intermolecular noncovalent interactions. A new type of diagram – the (RF, d) distribution – was introduced for highlighting the differences in noncovalent interactions of polymorphic modifications and for visual support of the previously introduced k–Φ criterion. Hydrogen bonding motifs in GAL polymorphs in comparison with nine polymorphs of pharmaceutical aripiprazole (another prolific polymorphic system) are discussed.