3-(1H-Indol-3-yl)-2-(2-nitrobenzenesulfonamido)-propanoic acid including an unknown solvate

In the title compound, C₁₇H₁₅N₃O ₆S, which crystallized with highly disordered methanol and/or water solvent molecules, the dihedral angle between the the indole and benzene ring systems is 5.3 (2)°, which allows for the formation of intramolecular π-π stacking interactions [centroid-centroid separations = 3.641 (3) and 3.694 (3) Å] and an approximate overall U-shape for the molecule. In the crystal, dimers linked by pairs of N_s - H⋯O_c (s = sulfonamide and c = carboxylate) hydrogen bonds generate R₂ ²(10) loops, whereas N_i - H⋯π (i = indole) interactions lead to chains propagating in [100] or [010]. Together, these lead to a three-dimensional network in which the solvent voids are present as intersecting (two-dimensional) systems of [100] and [010] channels. The title compound was found to contain a heavily disordered solvent molecule, which could be methanol or water or a mixture of the two. Due to its uncertain nature and the unresolvable disorder, the data were processed with the SQUEEZE option in PLATON [Spek (2009). Acta Cryst. D65, 148-155], which revealed 877.8 ų of solvent-accessible volume per unit cell and 126 electron-units of scattering density or 109.7 ų (16 electron units) per organic molecule. This was not included in the calculations of overall formula weight, density and absorption coefficient.