2,4-Diphenyl-6-trifluoromethyl-2,3-dihydro-1H,5H-pyrrolo[3,4-c]pyrrole-1,3-dione

The asymmetric unit of the title compound, C19H11F3N2O2, contains two crystallographically unique molecules which differ in the rotation of a phenyl ring and a –CF3 substituent. The dihedral angles involving the pyrrole ring and the attached phenyl ring are 62.82 (8) and 71.54 (7)° in the two molecules. The difference in the rotation of the CF3 groups with respect to the pyrrolo rings to which they are attached is 23.5(1)°. For one molecule, there is a close contact between an H atom and the centroid of the phenyl ring of an adjacent molecule (2.572 Å). A similar contact is lacking in the second molecule. In the crystal, N—H⋯O interactions connect adjacent molecules into a chain normal to (01). Crystallographically unique molecules alternate along the hydrogen-bonded chains.

The asymmetric unit of the title compound, C 19 H 11 F 3 N 2 O 2 , contains two crystallographically unique molecules which differ in the rotation of a phenyl ring and a -CF 3 substituent. The dihedral angles involving the pyrrole ring and the attached phenyl ring are 62.82 (8) and 71.54 (7) in the two molecules. The difference in the rotation of the CF 3 groups with respect to the pyrrolo rings to which they are attached is 23.5(1) . For one molecule, there is a close contact between an H atom and the centroid of the phenyl ring of an adjacent molecule (2.572 Å ). A similar contact is lacking in the second molecule. In the crystal, N-HÁ Á ÁO interactions connect adjacent molecules into a chain normal to (011). Crystallographically unique molecules alternate along the hydrogenbonded chains.

Comment
The biological activity of compounds with pyrrol-3,4-dicarboximide scaffolds includes analgesic, central nervous system depressive action, and antiproliferative activities (Malinka et al. 2005;Malinka et al. 1999;Shen et al. 2010). Furthermore, pyrrol-3,4-dicarboximides are very interesting compounds because of their structural similarity to lamellarins (Yu et al. 2011). The title compound was synthesized and its crystal structure is reported herein.
The asymmetric unit contains two molecules of the title compound (see Figure 1 for a view of the molecular structure).
After overlapping the central fused ring of the independent molecules using OLEX2 (see Figure 2; Dolomanov et al., 2009), it is clear that the molecules differ only in rotation of the phenyl ring and CF 3 substituents. The phenyl ring planes differ by approximately a 41° rotation about the N-C bond. The CF 3 substituent is rotated by 16.5°. The r.m.s. deviation of atomic positions between the two molecules is 0.56 Å (all atoms), 0.065 Å for matched atoms. The center of one of the phenyl rings that differ in orientation (C7-C12) has a close contact (2.572 Å) to the hydrogen atom bonded to C14 on a symmetry related molecule. This contact is lacking for the other molecule.
Intermolecular hydrogen bonds connect molecules into a ribbon throughout the crystal. Figure 3 shows molecular packing and hydrogen bonds in the crystal. Hydrogen bonds exist between O1 and N3 (2.8395 Å) and O4 and N1 (2.8757 Å) and connect molecules into a chain normal to (0 1 -1). Crystallographically unique molecules alternate along the hydrogen bonded chains. The graph set description is C2,2(12)>a>b (determined using Mercury (Macrae et al., 2008)).

Refinement
All hydrogen atoms were visible in a difference Fourier map and were added at calculated positions. Bonds distances are set to 0.95 Å for carbon-hydrogen bonds, and 0.88 Å for nitrogen-hydrogen bonds.