1-(Anthracen-1-yl)pyrrolidine-2,5-dione

In the molecular structure of title compound, C18H13NO2, the succinimide ring is orientated away from the plane of the anthracene moiety by 71.94 (4)°. The crystal structure features three different types of intermolecular interactions, viz. C—H⋯O, C—H⋯π and π–π bonds. Molecules along the b axis stack on each other as a result of π–π interactions which have a centroid–centroid distance of 3.6780 (15) Å, while C—H⋯π interactions are present between neigbouring stacks. Also, acting between the stacks are the C—H⋯O interactions between the aromatic H atoms of the anthracene and the O atoms of the succinimide.

In the molecular structure of title compound, C 18 H 13 NO 2 , the succinimide ring is orientated away from the plane of the anthracene moiety by 71.94 (4) . The crystal structure features three different types of intermolecular interactions, viz. C-HÁ Á ÁO, C-HÁ Á Á andbonds. Molecules along the b axis stack on each other as a result ofinteractions which have a centroid-centroid distance of 3.6780 (15) Å , while C-HÁ Á Á interactions are present between neigbouring stacks. Also, acting between the stacks are the C-HÁ Á ÁO interactions between the aromatic H atoms of the anthracene and the O atoms of the succinimide.
Data collection: APEX2 (Bruker 2005); cell refinement: SAINT (Bruker 2005); data reduction: SAINT; program(s) used to solve structure: SHELXS97 (Sheldrick, 2008); program(s) used to refine structure: SHELXL97 (Sheldrick, 2008); molecular graphics: ORTEP-3 (Farrugia, 1997) and SCHAKAL99 (Keller, 1999); software used to prepare material for publication: WinGX (Farrugia, 1999) and PLATON (Spek, 2009  The compound anthracene has been known for a long time and its properties have been extensively studied. The regioand sterio-selectivity of substituted anthracenes in Diels-Alder reactions have been investigated and reported (Alston et al., 1979;Meek et al., 1960;Kaplan & Conroy, 1963;Verma & Singh, 1977;Singh & Ningombom, 2010). A study of the title compound and 1-succinimidonaphthalene involving synthesis, NMR experiments and molecular mechanics has been reported by Hubbard et al. (1992). longer than the 1.39Å typical of aromatic rings. As a consequence the rings containing these have been flagged as having larger than average C6-ring C-C bond lengths by PLATON (Spek, 2009), suggesting that the succinimide group has a significant effect on the charge distribution within the anthracene ring. The crystal structure contains three different types of intermolecular interactions, these include C-H···O, C-H···π and π-π interactions (Fig. 2). The π-π interaction occurs over a Cg1···Cg2 distance of 3.678 (2)Å between the rings defined by C1-C5/C14 (Cg1) and C7-C12 (Cg2). This leads to the stacking of molecules along b axis. Geometrical details of the C-H···π and C-H···O interactions are given in the Table   1.

Experimental
The title compound was synthesized with very low yield (a few crystals) by reaction of 1-aminoanthracene (0.200 g, 1 mmol) with succinic anhydride (0.107 g, 1 mmol) in the presence of dioxane as a solvent (3 ml) by strirring at room temperature for a few hours. Thionyl chloride (3 ml) in dioxane (2 ml) was then slowly added to the reaction mixture at room temperature. The mixture was then kept at 323 K for 12 h, followed by neutralization of excess thionyl chloride by pouring the mixture into a beaker containing ice. This mixture was then filtered yielding a dark brown material, which after recrystallization by slow evaporation from chloroform yielded a few crystals suitable for analysis by X-ray diffraction.

Refinement
All H atoms were positioned geometrically, and allowed to ride on their parent atoms, with C-H bond lengths of 0.95Å for aromatic H or 0.99Å for methylene H and U iso (H) = 1.2U eq (C). The 1449 Friedel pairs were merged during structure refinement.

Figure 1
The molecular structure of the title compound, showing the atomic numbering scheme. Displacement ellipsoids are drawn at the 50% probability level. H atoms are presented as small spheres of arbitrary radius.  C-H···O, C-H···π and π-π interactions in the structure of the title compound. The C-H···π and π-π interactions are respectively indicated by dollar ($) or hash (#) symbols. where P = (F o 2 + 2F c 2 )/3 (Δ/σ) max = 0.002 Δρ max = 0.17 e Å −3 Δρ min = −0.19 e Å −3 Special details Geometry. All s.u.'s (except s.u. in the dihedral angle between two l.s. planes) are estimated using the full covariance matrix. The cell s.u.'s are taken into account individually in the estimation of s.u.'s in distances, angles and torsion angles; correlations between s.u.'s in cell parameters are only used when they are defined by crystal symmetry. An approximate (isotropic) treatment of cell s.u.'s is used for estimating s.u.'s 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 R-factors(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.