title: Dibenzo[b,g]indeno-[1',2':3,4]fluoreno[1,2-d]oxonine-5,11,16,21-tetra-one.
abstract: The asymmetric unit of the title compound, C34H16O5, contains two independent mol-ecules (A and B) with similar conformations. The two benzene rings attached to the nine-membered ring are inclined to one another at 63.62 (14)° in mol-ecule A and 68.23 (12)° in mol-ecule B. One intra-moleculer C-H⋯O hydrogen bond occurs in mol-ecule A and two are observed in mol-ecule B. In the crystal, mol-ecules are linked by weak C-H⋯O hydrogen bonds, forming a three-dimensional network structure with R(2)2(10) and R(2)2(24) ring motifs. Aromatic π-π stacking interactions [centroid-centroid distances = 3.7572 (19), 3.6996 (19) and 3.7043 (19) Å] are also observed. The unit cell contains a pair of voids of 37 (2) Å(3) about an inversion centre but the residual electron density (highest peak = 0.19 e Å(-3) and deepest hole = -0.20 e Å(-3)) in the difference Fourier map suggests that no solvent mol-ecule occupies this void.
authors.affiliation: Chemistry Department, Faculty of Science, Minia University, Egypt ; Chemistry and Environmental Division, Manchester Metropolitan University, Manchester M1 5GD, England.
authors.forename: Shaaban Kamel
authors.initials: SK
authors.lastname: Mohamed
authors.forename: Mehmet
authors.initials: M
authors.lastname: Akkurt
authors.forename: Muhammad N
authors.initials: MN
authors.lastname: Tahir
authors.forename: Antar A
authors.initials: AA
authors.lastname: Abdelhamid
authors.forename: Adel A
authors.initials: AA
authors.lastname: Marzouk