Crystal data

disorder in main residue; R factor = 0.056; wR factor = 0.168; data-to-parameter ratio = 22.3. The asymmetric unit of the title compound, C27H16F2N2O4, consists of two crystallographically independent molecules (A and B). In molecule B, the isoindoline-1,3-dione ring system is disordered over two set of sites with a site-occupancy ratio of 0.658 (12):0.342 (12). In molecule A, the fluoro-substituted benzene rings make dihedral angles of 18.36 (8) and 46.37 (8) with the central benzene ring, whereas the corresponding angles are 40.90 (8) and 52.89 (9) in molecule B. The isoindoline ring system in molecule A and the major and minor components of the disordered isoindoline ring system in molecule B make dihedral angles of 58.50 (4), 54.13 (16) and 70.01 (28) , respectively, with their attached benzene rings, linked through the amide group. An intramolecular O— H O hydrogen bond generates an S(6) ring in each molecule. In the crystal, molecules are linked by N—H O, C—H F and C—H O hydrogen bonds into sheets lying parallel to the bc plane. The crystal studied was a non-merohedral twin with a refined twin component ratio of 0.9316 (8):0.0684 (8). Related literature For related structures and background to terphenyls and their oxadiazole derivatives, see: Fun et al. (2012a,b); Samshuddin et al. (2011). For the planarity of isoindoline, see: Asad et al. (2011). For hydrogen-bond motifs, see: Bernstein et al. (1995). For the stability of the temperature controller used in the dat