Crystal structure of 8-[7, 8-bis(4-chlorobenzoyl)-7H-cyclopenta[a]acenaphthylen-9-yl]naphthalene-1-carboxylic acid

The title compound, C₄₀H₂₂Cl₂O₄, was formed by a Michael-Aldol domino reaction sequence, which coupled acenaphthenequinone with 4-chloroaceto-phenone in the presence of KOH in methanol. The dihedral angles between the central cyclopenta[a]acenaphthylene fused-ring system (r.m.s. deviation = 0.066 Å) and the 4-chlorobenzoyl rings are 62.25(10) and 70.19(10)°. The dihedral angle between the central ring system and the naphthoic acid grouping is 62.46 (7)°. This twisting of the pendant rings facilitates the formation of an intramolecular aromatic π-π stacking interaction between the 4-chlorobenzoyl and naphthoic acid rings, with centroid-centroid distances of 3.4533 (16) and 3.5311 (16) Å, and a C - H⋯π interaction between one of the H atoms of the central moiety and the 4-chlorobenzoyl ring with an H⋯π distance of 2.57 Å. In the crystal, carboxylic acid inversion dimers generate R ₂²(8) loops. The dimers are linked by weak C - H⋯O and C - H⋯Cl hydrogen bonds and C - H⋯π interactions, generating a three-dimensional architecture.