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 190 K. In each of the two isomeric compounds, (I) and (II), C(7)H(4)ClNO(4)·C(9)H(6)N(2)O(2), the acid and base mol­ecules are held together by O—H⋯N and C—H⋯O hydrogen bonds. In compound (III), C(9)H(8)NO(+)·C(7)H(3)ClNO(4) (−), 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 ([Image: see text]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 ([Image: see text]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 2(1) 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.