Examining the Non-Covalent Interactions for Two Polymorphs of a 2,1,3-benzoxadiazole Derivative

Two polymorphs of a benzoxadiazole derivative were examined to determine the interactions leading to the formation of two distinct crystalline forms. Hirshfeld surface analysis was used to establish and contrast the interactions in the two samples. Fingerprints derived from the surface analysis were used to distinguish and lead the analysis in discovering the different interactions in the two crystals. pi interactions, specifically, pi-hole interactions with a nitro moiety, were found to play an important role in the formation of the crystal structure. Further, carbonyl interactions and pi-stacking contribute to the overall relative stability of the different conformational polymorphs. Calculated energy frameworks were used to help visualize the interactions between molecules in the crystal structure, supported by an understanding of the individual interactions. The experimental data were supplemented with theoretical studies to establish a through understanding of these heterocyclic systems.