Crystal structure of 1,2-bis-(4-fluoro-phen-yl)-1-hy-droxy-2,3,8-tri-meth-oxy-acenaphthene: formation of a five-membered intra-molecular O-H⋯O hydrogen-bonded ring.

The structure of the title compound, C27H22F2O4, at 193 K has triclinic (P ) symmetry. The hy-droxy and meth-oxy groups at the 1,2-positions of the acenaphthene core display a cis configuration. Both substituents are involved in the formation of a five-membered intra-molecular O-H⋯O hydrogen-bonded ring. The 4-fluoro-phenyl rings make dihedral angles of 87.02 (7) and 51.86 (8)° with the naphthalene ring system. In the crystal, a pair of non-classical C-H⋯O hydrogen bonds forms centrosymmetric dimeric structures. The dimeric aggregates are linked in the ac plane through non-classical C-H⋯F hydrogen bonds and C-H⋯π interactions.

Crystal structure and Hirshfeld surface analysis of 2-hy-droxy-7-meth-oxy-1,8-bis-(2,4,6-tri-chloro-benzo-yl)naphthalene.

In the title compound, C25H12Cl6O4, the two carbonyl groups are oriented in a same direction with respect to the naphthalene ring system and are situated roughly parallel to each other, while the two 2,4,6-tri-chloro-benzene rings are orientated in opposite directions with respect to the naphthalene ring system: the carbonyl C-(C=O)-C planes subtend dihedral angles of 45.54 (15) and 30.02 (15)° to the naphthalene ring system are. The dihedral angles formed by the carbonyl groups and the benzene rings show larger differences, the C=O vectors being inclined to the benzene rings by 46.39 (16) and 79.78 (16)°. An intra-molecular O-H⋯O=C hydrogen bond forms an S(6) ring motif. In the crystal, no effective inter-molecular hydrogen bonds are found; instead, O⋯Cl and C⋯Cl close contacts are observed along the 21 helical-axis direction. The Hirshfeld surface analysis reveals several weak interactions, the major contributor being Cl⋯H/H⋯Cl contacts.