Crystal structure of 1,3-bis(1,3-dioxoisoindolin-1-yl)urea dihydrate: a urea-based anion receptor

The whole molecule of the title compound, C17H10N4O5·2H2O, is generated by twofold rotation symmetry and it crystallized as a dihydrate. The planes of the phthalimide moieties and the urea unit are almost normal to one another, with a dihedral angle of 78.62 (9)°. In the crystal, molecules are linked by N—H...O and O—H...O hydrogen bonds, forming a three-dimensional framework structure. The crystal packing also features C—H...O hydrogen bonds and slipped parallel π–π interactions [centroid–centroid distance = 3.6746 (15) Å] involving the benzene rings of neighbouring phthalimide moieties.