A charge-transfer complex of benzene with a highly twisted perylene derivative

2C6H6.C26H6Cl8N2O4, benzene-1,2,5,6,7,8-11,12-octachloro-N,N'-dimethylperylene-3 ,4:9,10-bis- (dicarboximide) (Cl8DMP) (2/1), Mr = 850.20, orthorhombic, Pna2(1), a = 23.076 (2), b = 7.2492 (6), c = 20.277 (2) A, V = 3392.0 (8) A3, Z = 4, Dm = 1.69 (1), Dx = 1.665 g cm-3, mu (Mo K alpha, lambda = 0.71073 A) = 7.1 cm-1, F(000) = 1712, T = 297 (1) K, RF = 0.061 for 2134 observed reflections. The structure contains alternating benzene and Cl8DMP molecules stacked along b to form a 2:1 donor-acceptor complex. The Cl8DMP molecule is highly twisted as a result of short intramolecular bay Cl...Cl contacts [3.109 (3), 3.136 (3) A]. The central ring of the perylene fragment is substantially distorted from planarity; internal torsion angles range from 16 (1) to 32 (1) degrees.