Crystal structures of 3-chloro-2-nitrobenzoic acid with quinoline derivatives: 3-chloro-2-nitrobenzoic acid-5-nitroquinoline (1/1), 3-chloro-2-nitrobenzoic acid-6-nitroquinoline (1/1) and 8-hydroxyquinolinium 3-chloro-2-nitrobenzoate

The structures of three compounds of 3-chloro-2-nitrobenzoic acid with 5-nitroquinoline, (I), 6-nitroquinoline, (II), and 8-hydroxyquinoline, (III), have been determined at 190K. In each of the two isomeric compounds, (I) and (II), C7H4ClNO4·C9H6N2O2, the acid and base molecules are held together by O - H⋯N and C - H⋯O hydrogen bonds. In compound (III), C9H8NO⁺·C7H3ClNO4 ^-, an acid-base interaction involving H-atom transfer occurs and the H atom is located at the N site of the base molecule. In the crystal of (I), the hydrogen-bonded acid-base units are linked by C - H⋯O hydrogen bonds, forming a tape structure along the b-axis direction. Adjacent tapes, which are related by a twofold rotation axis, are linked by a third C - H⋯O hydrogen bond, forming wide ribbons parallel to the ( 03) plane. These ribbons are stacked via π-π interactions between the quinoline ring systems [centroid-centroid distances = 3.4935(5)-3.7721(6)Å], forming layers parallel to the ab plane. In the crystal of (II), the hydrogen-bonded acid-base units are also linked into a tape structure along the b-axis direction via C - H⋯O hydrogen bonds. Inversion-related tapes are linked by further C - H⋯O hydrogen bonds to form wide ribbons parallel to the ( 08) plane. The ribbons are linked by weak π-π interactions [centroid-centroid distances = 3.8016(8)-3.9247(9)Å], forming a three-dimensional structure. In the crystal of (III), the cations and the anions are alternately linked via N - H⋯O and O - H⋯O hydrogen bonds, forming a 21 helix running along the b-axis direction. The cations and the anions are further stacked alternately in columns along the a-axis direction via π-π interactions [centroid-centroid distances = 3.8016(8)-3.9247(9)Å], and the molecular chains are linked into layers parallel to the ab plane through these interactions.