2,5-Dihexyl-3,6-diphenylpyrrolo[3,4-c]pyrrole-1,4(2H,5H)-dione

The asymmetric unit of the title compound, C30H36N2O2, contains one half-molecule, the other half being generated by a crystallographic inversion centre. The crystal structure is devoid of any classical hydrogen bonds however, non-classical C—H⋯O interactions link the molecules into chains propagating in [001] and a C—H⋯π interaction leads to the formation of a two-dimensional network in (011).

The asymmetric unit of the title compound, C 30 H 36 N 2 O 2 , contains one half-molecule, the other half being generated by a crystallographic inversion centre. The crystal structure is devoid of any classical hydrogen bonds however, non-classical C-HÁ Á ÁO interactions link the molecules into chains propagating in [001] and a C-HÁ Á Á interaction leads to the formation of a two-dimensional network in (011).

Experimental
The molecular structure of the title molecule is illustrated in Fig. 1. It is situated on an inversion center. The pyrrolopyrrole 8-membered ring is almost planar (C8 has a maximum deviation of 0.4636 (15) Å). Because of the steric effect of the alkyl group, the pyrrolopyrrole and phenyl rings are not coplanar. The dihedral angle between the mean planes of these rings is 34.38 (9) °.

Experimental
The starting reactant, 3,6-diphenyl-2,5-dihydro-1,4-diketopyrrolo[3,4-c]pyrrole-1,4-dione (L), was prepared following the literature procedure (Morton et al., 2002). The synthesis of the title compound was carried out under a nitrogen atmosphere. L (0.59 g, 0.00204 mol) was stirred in 1-methyl-2-pyrolidinone (30 mL) at room temperature. Potassium-tert-butoxide (0.230 g, 0.00816 mmol) was then added follwed by the addition of the n-hexyl bromide (0.340 g, 0.00204 mmol) and the mixture was stirred for 18 hours, after which it was poured into 30 mL of cold water. The precipitate formed was filtered off and the crude product purified by column chromatography, using ethyl acetate/n-hexane (1:3) as eluent. Re-crystallization from methanol produced orange prism-like crystals of the title compound, suitable for X-ray analysis. Yield: 44%; m.p. =  Fig. 1. A view of the molecular structure of the title compound, with displacement ellipsoids drawn at the 50% probability level. The unlabelled atoms are related by the inversion center (symmetry code = -x, 1-y, 1-z).

Special details
Geometry. All esds (except the esd in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell esds are taken into account individually in the estimation of esds in distances, angles and torsion angles; correlations between esds in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell esds is used for estimating esds involving l.s. planes.
Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating Rfactors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.