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

Abstract

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), 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 (\overline{1}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 (\overline{3}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.