Polymorphic structures of 3-phenyl-1H-1,3-benzodiazol-2(3H)-one

The polymorphic structures (I and II) of 3-phenyl-1H-1,3-benzodiazol-2(3H)-one, C13H10N2O, acquired from pentane diffusion into the solution in THF, are reported. The structures show negligible differences in bond distances and angles, but the C-N-C-C torsion angles between the backbone and the phenyl substituent, 123.02 (15)degrees for I and 137.18 (11)degrees for II, are different. Compound I features a stronger C=O center dot center dot center dot H-N hydrogen bond than that in II, while the structure of II exhibits a stronger pi-pi interaction than in I, as confirmed by the shorter intercentroid distance [3.3257 (8) angstrom in II in comparison to 3.6862 (7) angstrom in I]. Overall, the supramolecular interactions of I and II are distinct, presumably originating from the variation in the dihedral angle.