3-Amino-1-phenyl-1H-benzo[f]chromene-2-carbonitrile

In the title compound, C₂₀H₁₄N₂O, the phenyl ring is almost normal to the naphthalene ring system with a dihedral angle of 86.72 (9)°. The 4H-pyran ring fused with the naphthalene ring system has a boat conformation. In the crystal, mol­ecules are linked into a helical supra­molecular chain along the b axis via N—H...N hydrogen bonds. The chains are consolidated into a three-dimensional architecture by C—H...π inter­actions.

14-Bromo-12-chloro-2,16-dioxa­penta­cyclo­[7.7.5.0^1,21.0^3,8.0^10,15]henicosa-3(8),10,12,14-tetra­ene-7,20-dione

In the title compound, C₁₉H₁₆BrClO₄, both the fused xanthene rings and one of the cyclo­hexane rings adopt envelope conformations, while the other cyclo­hexane ring is in a chair conformation. In the crystal, mol­ecules are linked by C—H...O hydrogen bonds, forming infinite chains running along [10-1] incorporating R₂²(16) ring motifs. In addition, C—H...π inter­actions and weak π–π stacking inter­actions [centroid–centroid distance = 3.768 (3) Å] help to consolidate the packing.

1-{(E)-[(2-Fluoro-5-nitro­phen­yl)imino]­meth­yl}naphthalen-2-ol

The title mol­ecule, C₁₇H₁₁FN₂O₃, is nearly planar [maximum deviation = 0.197 (1) Å] and the mol­ecular conformation is stabilized by an N—H...O hydrogen bond forming an S(6) ring motif. The H atom of the intra­molecular hydrogen bond was found to be disordered over two sites and thus both the hy­droxy and keto tautomers are simultaneously present in the solid. Refinement of the occupancy of this site suggests that the hy­droxy form is the major component [occupancy refined to 0.59 (3):0.41 (3)]. Bond lengths are also largely consistent with dominance of the hy­droxy form. In the crystal, mol­ecules are linked by C—H...O hydrogen bonds, forming layers parallel to (101). π–π stacking inter­actions [centroid–centroid distances = 3.5649 (9) and 3.7579 (9) Å] inter-connect these layers.

12-(2-Hy­droxy-6-oxo­cyclo­hex-1-en­yl)-9,10-di­hydro-8H-benzo[a]xanthen-11(12H)-one

In the xanthenone system of the title compound, C₂₃H₂₀O₄, the pyran ring has a maximum deviation of 0.111 (1) Å from planarity and the outer cyclo­hexene ring exhibits a puckered conformation. The three methyl­ene C atoms of the cyclo­hexene ring bonded to the pyran unit are disordered over two sets of sites [occupancies = 0.570 (3) and 0.430 (3)]. In the crystal, mol­ecules are linked by C—H...O and O—H...O hydrogen bonds, forming a two-dimensional network parallel to (110). A C—H...π inter­action occurs between these networks.

N-(2-Nitro­phen­yl)furan-2-carboxamide

In the title furan­carboxamide derivative, C₁₁H₈N₂O₄, the benzene and furan rings are rotated from the mean plane of the central fragment by 2.68 (5) and 7.03 (4)°, respectively. The nitro group forms a dihedral angle of 10.15 (5)° with the adjacent benzene ring. In the crystal, mol­ecules are linked by weak C—H...O inter­actions, forming helical chains running along [010].

2,4,6-Tri­nitro­phenyl furan-2-carboxyl­ate

In the title carboxyl­ate derivative, C₁₁H₅N₃O₉, the picryl ring forms an angle of 75.79 (7)° with the ester fragment, indicating a near perpendicular disposition. The nitro substituents are variously oriented with respect to the picryl ring [dihedral angles = 3.22 (10), 16.03 (12) and 36.63 (10)°]. In the crystal, mol­ecules form helical chains sustained by C—H...O inter­actions along [010]. The furanyl residue is disordered, having two coplanar slightly displaced orientations [major component = 0.730 (9)].