Crystal forms in pharmaceutical applications: olanzapine, a gift to crystal chemistry that keeps on giving

Development of a scalar-based geometric parameterization approach for the crystal structure landscape of dithienylethene-based crystalline solids

Dithienylethenes (DTEs) are a promising class of organic photoswitches that can be used to create crystalline solids with properties controlled by light. However, the ability of DTEs to adopt multiple conformations, only one of which is photoactive, complicates the rational design of these materials. Herein, the synthesis and structural characterization of 19 crystalline solids containing a single DTE molecule are described. A novel D-D analysis of the molecular geometries obtained from rotational potential energy surface calculations and the ensemble of experimental structures were used to construct a crystal landscape for DTE. Of the 19 crystal structures, 17 contained photoinactive DTE rotamers and only 2 were photoactive. These results highlight the challenges associated with the design of these materials. Overall, the D-D analysis described herein provides rapid, effective and intuitive means of linking the molecular structure to photoactivity that could be applied more broadly to afford a general strategy for producing photoactive diarylethene-based crystalline solids.

The extensive solid-form landscape of sulfathiazole: hydrogen-bond topology and node shape

Patterns of hydrogen bonds are described in a set of 101 crystal structures containing sulfathiazole. Topological analysis of the hydrogen-bond nets is augmented by comparison of the shapes of the nodes extracted from each net.

Steric influence on solvate formation – a comparison of resorcylic acid and two brominated derivatives

Unbalanced steric bulk can lead to increased solvate formation as shown in non-, mono- and dibrominated resorcylic acid.

Crystal engineering in IUCrJ: from 'the' crystal structure to 'a' crystal structure

What is 'structure' in the context of a molecular solid?