title: Crystal structures of iso-quinoline-3-chloro-2-nitro-benzoic acid (1/1) and isoquinolinium 4-chloro-2-nitro-benzoate.
abstract: In each of the title isomeric compounds, C9H7.3N·C7H3.7ClNO4, (I), and C9H8N·C7H3ClNO4, (II), of iso-quinoline with 3-chloro-2-nitro-benzoic acid and 4-chloro-2-nitro-benzoic acid, the two components are linked by a short hydrogen bond between a base N atom and a carb-oxy O atom. In the hydrogen-bonded unit of (I), the H atom is disordered over two positions with N and O site occupancies of 0.30 (3) and 0.70 (3), respectively, while in (II), an acid-base inter-action involving H-atom transfer occurs and the H atom is located at the N site. In the crystal of (I), the acid-base units are connected through C-H⋯O hydrogen bonds into a tape structure along the b-axis direction. Inversion-related adjacent tapes are further linked through π-π inter-actions [centroid-centroid distances = 3.6389 (7)-3.7501 (7) Å], forming a layer parallel to (001). In the crystal of (II), the acid-base units are connected through C-H⋯O hydrogen bonds into a ladder structure along the a-axis direction. The ladders are further linked by another C-H⋯O hydrogen bond into a layer parallel to (001).
authors.affiliation: Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
authors.forename: Kazuma
authors.initials: K
authors.lastname: Gotoh
authors.affiliation: Department of Chemistry, Faculty of Science, Okayama University, Okayama 700-8530, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Ishida
keywords: chloro- and nitro-substituted benzoic acid; crystal structure; iso­quinoline; short hydrogen bond