Diethyl 3,4-dimethyl­thieno[2,3-b]thio­phene-2,5-dicarboxyl­ate

In the title compound, C₁₄H₁₆O₄S₂, the thieno[2,3-b]thio­phene ring systems are planar [maximum deviation = 0.008 (2) Å]. The mol­ecular conformation is stabilized by intra­molecular C—H...O hydrogen bonds, while the crystal packing is stabilized by C—H...O, C—H...π and π–π stacking [centroid–centroid distance = 3.6605 (14) Å] inter­actions, which lead to supra­molecular layers in the ab plane.

4-Phenyl-1H-1,5-benzodiazepin-2(3H)-one

In the title compound, C₁₅H₁₂N₂O, the phenyl ring makes a dihedral angle of 32.45 (9)° with the benzene ring of the 1,5-benzodiazepin-2-one unit. The seven-membered ring adopts a boat conformation with the methyl­ene group as the prow and the fused benzene-ring C atoms as the stern. In the crystal, inversion dimers linked by pairs of N—H...O hydrogen bonds generate R₂²(8) loops. The dimers are further linked by C—H...O hydrogen bonds, so forming a column along the a-axis direction.

Dibenzo[b,g]indeno­[1′,2′:3,4]fluoreno[1,2-d]oxonine-5,11,16,21-tetra­one

The asymmetric unit of the title compound, C₃₄H₁₆O₅, contains two independent mol­ecules (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 mol­ecule A and 68.23 (12)° in mol­ecule B. One intra­moleculer C—H...O hydrogen bond occurs in mol­ecule A and two are observed in mol­ecule B. In the crystal, mol­ecules are linked by weak C—H...O hydrogen bonds, forming a three-dimensional network structure with R²₂(10) and R²₂(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) ų 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 mol­ecule occupies this void.