Three polymorphs of 3-(3-phenyl-1H-1,2,4-triazol-5-yl)-2H-1-benzopyran-2-one formed from different solvents

The polymorphic study of 3-(3-phenyl-1H-1,2,4-triazol-5-yl)-2H-1-benzopyran-2-one, C17H11N3O2, was performed due to its potential biological activity and revealed three polymorphic modifications in the triclinic space group P (1) over bar, the monoclinic space group P2(1) and the orthorhombic space group Pbca. These polymorphs have a one-column layered type of crystal organization. The strongest interactions between the molecules of the studied structures is stacking between pi-systems, while N-H center dot center dot center dot N and C-H center dot center dot center dot O hydrogen bonds link stacked columns forming layers as a secondary basic structural motif. C-H center dot center dot center dot pi hydrogen bonds were observed between neighbouring layers and their role is the least significant in the formation of the crystal structure. Packing differences between the polymorphic modifications are minor and can be identified only using an analysis based on a comparison of the pairwise interaction energies.