Crystal structures of 3-chloro-2-nitro-benzoic acid with quinoline derivatives: 3-chloro-2-nitro-benzoic acid-5-nitro-quinoline (1/1), 3-chloro-2-nitro-benzoic acid-6-nitro-quinoline (1/1) and 8-hy-droxy-quinolinium 3-chloro-2-nitro-benzoate.

Kazuma Gotoh,Hiroyuki Ishida

doi:10.1107/s2056989019012799

Abstract

The structures of three compounds of 3-chloro-2-nitro-benzoic acid with 5-nitro-quinoline, (I), 6-nitro-quinoline, (II), and 8-hy-droxy-quinoline, (III), have been determined at 190 K. In each of the two isomeric compounds, (I) and (II), C7H4ClNO4·C9H6N2O2, the acid and base mol-ecules are held together by O-H⋯N and C-H⋯O hydrogen bonds. In compound (III), C9H8NO+·C7H3ClNO4 -, an acid-base inter-action involving H-atom transfer occurs and the H atom is located at the N site of the base mol-ecule. 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 inter-actions 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 inter-actions [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 inter-actions [centroid-centroid distances = 3.8016 (8)-3.9247 (9) Å], and the mol-ecular chains are linked into layers parallel to the ab plane through these inter-actions.

Highlights

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 the crystal of (III), the cations and the anions are alternately linked via N—HÁ Á ÁO and O—HÁ Á ÁO hydrogen bonds, forming a 21 helix running along the b-axis direction
The hydrogen bonds formed between organic acids and organic bases vary from an O—HÁ Á ÁN type to an OÀÁ Á ÁH—N+ type depending on the pKa values of the acids and bases as well as intermolecular interactions in the crystals, and at an appropriate ÁpKa [pKa(base) À pKa(acid)] value, a short strong hydrogen bond with a broad single minimum potential energy curve for the H atom or a double-minimum potential is observed (Schmidtmann & Wilson, 2008; Gilli & Gilli, 2009)

Summary

Chemical context

The hydrogen bonds formed between organic acids and organic bases vary from an O—HÁ Á ÁN type to an OÀÁ Á ÁH—N+ type depending on the pKa values of the acids and bases as well as intermolecular interactions in the crystals, and at an appropriate ÁpKa [pKa(base) À pKa(acid)] value, a short strong hydrogen bond with a broad single minimum potential energy curve for the H atom or a double-minimum potential is observed (Schmidtmann & Wilson, 2008; Gilli & Gilli, 2009). For the system of quinoline–chloro- and nitro-substituted benzoic acids, we have shown that three compounds of quinoline with 3-chloro-2-nitrobenzoic acid, 4-chloro-2-nitrobenzoic acid and 5-chloro-2-nitrobenzoic acid, the ÁpKa values of which are 3.08, 2.93 and 3.04, respectively, have a. Similar OÁ Á ÁHÁ Á ÁN hydrogen bonds have been observed in compounds of phthalazine with 3-chloro-2-nitrobenzoic acid and 4-chloro-2-nitrobenzoic acid with ÁpKa values of 1.65 and 1.50, respectively (Gotoh & Ishida, 2011), and of isoquinoline with 3-chloro-2-nitrobenzoic acid with ÁpKa = 3.58 (Gotoh & Ishida, 2015). We report here the crystal structures of the title compounds in order to extend our studies of short hydrogen bonding in pyridine derivative–chloro- and nitro-substituted benzoic acid systems. The ÁpKa values are 0.98 and 1.42 and 3.02 for 3chloro-2-nitrobenzoic acid–5-nitroquinoline (1/1), (I), 3chloro-2-nitrobenzoic acid–6-nitroquinoline (1/1), (II), and 8hydroxyquinolium 3-chloro-2-nitrobenzoate, (III), respectively

Structural commentary

Supramolecular features

Database survey

Synthesis and crystallization

Refinement