Tahir M Nawaz, Shad Hazoor Ahmad
Acta Crystallogr Sect E Struct Rep Online. 2010 Nov 27;66(Pt 12):o3314. doi: 10.1107/S1600536810048579.
The zwitterionic title compound, C(16)H(12)N(2)O(3), was obtained as a result of the condensation of 5-amino-salicylic acid and 1H-indole-3-carbaldehyde. The whole mol-ecule is roughly planar: the 4-hy-droxy-anilinic group and the 1H-indole-3-carbaldehyde moieties are only slightly twisted, making a dihedral angle of 7.77 (11)°, whereas, the carboxyl-ate group makes a dihedral angle of 3.34 (45)° with the parent 4-hy-droxy-anilinic group. S(6) ring motifs are formed due to intra-molecular O-H⋯O hydrogen bonding. In the crystal, inter-molecular N-H⋯O and C-H⋯O hydrogen bonds build up pseudo-rings with R(1) (2)(4), R(2) (1)(7) and R(2) (2)(14) ring motifs. These pseudo-dimers are further linked by N-H⋯O hydrogen bonds into a chain extending along [101]. C-H⋯π inter-actions also occur, along with offset π-π inter-actions between the anilinic phenyl and the heterocyclic five-membered rings with a centroid-centroid distance of 3.5716 (19) Å.
两性离子标题化合物C(16)H(12)N(2)O(3)是5-氨基水杨酸与1H-吲哚-3-甲醛缩合反应的产物。整个分子大致呈平面状：4-羟基苯胺基和1H-吲哚-3-甲醛部分仅有轻微扭曲，二面角为7.77 (11)°，而羧酸根基团与母体4-羟基苯胺基的二面角为3.34 (45)°。由于分子内O-H⋯O氢键形成了S(6)环模式。在晶体中，分子间N-H⋯O和C-H⋯O氢键形成了具有R(1)(2)(4)、R(2)(1)(7)和R(2)(2)(14)环模式的假环。这些假二聚体通过N-H⋯O氢键进一步连接成沿[101]方向延伸的链。还存在C-H⋯π相互作用，以及苯胺基苯基与杂环五元环之间的偏移π-π相互作用，质心间距为3.5716 (19) Å。
