(3,5-Dimethylphenyl)[8-(3,5-dimethylbenzoyl)-2,7-dimethoxynaphthalen-1-yl]methanone

In the title molecule, C30H28O4, the interplanar angle between the two benzene rings of the 3,5-dimethylbenzoyl groups is 50.35 (7)°. The dihedral angles between the two benzene rings and the naphthalene ring system are 81.87 (6) and 83.55 (6)°. In addition, the conformations of the pairs of methyl groups and their counterparts differ from each other though their environment is very similar. In the crystal, weak C—H⋯O interactions occur.

In the title molecule, C 30 H 28 O 4 , the interplanar angle between the two benzene rings of the 3,5-dimethylbenzoyl groups is 50.35 (7) . The dihedral angles between the two benzene rings and the naphthalene ring system are 81.87 (6) and 83.55 (6) . In addition, the conformations of the pairs of methyl groups and their counterparts differ from each other though their environment is very similar. In the crystal, weak C-HÁ Á ÁO interactions occur.
As a part of our continuing study on the molecular structures of these homologous molecules, the crystal structure of title compound, peri-aroylnaphthalene bearing two methyl groups at 3,5-positions on the phenyl group, is discussed in this article.
The title molecule is displayed in Fig. 1. Two 3,5-dimethylphenyl groups are out of the plane of the naphthalene ring.
The interplanar angle between the best planes of the two phenyl rings (C12\C17 and C19\C24) is 50.35 (7)°. On the other hand, the two interplanar angles between the best planes of the 3,5-dimethylphenyl rings and the naphthalene ring are 81.87 (6) and 83.55 (6)°, respectively.
The torsion angles between the carbonyl groups and the naphthalene ring are 113.52 (15) In the crystal structure, the molecular packing of the title compound is stabilized mainly by van der Waals interactions.

Refinement
All the H atoms were found in the difference electron density map and were subsequently refined in the riding atom approximation, with C-H = 0.95 (aryl) and 0.98 (methyl) Å, and with U iso (H) = 1.2U eq (C aryl ) and U iso (H) = 1.5U eq (C methyl ).
The methyl H atoms C29 are less clear, indicating possible disorder over 4 positions that has not been described in the published model.  The title molecule with the displacement ellipsoids drawn at the 50% probability level.  Two weak intermolecular C-H···O interactions [distances: H7···O1 i = 2.55 Å and H26a···O1 i = 2.59 Å; symmetry code: Refinement. Refinement of F 2 against ALL reflections. The weighted R-factor wR and goodness of fit S are based on F 2 , conventional R-factors R are based on F, with F set to zero for negative F 2 . The threshold expression of F 2 > σ(F 2 ) is used only for calculating R-factors(gt) etc. and is not relevant to the choice of reflections for refinement. R-factors based on F 2 are statistically about twice as large as those based on F, and R-factors based on ALL data will be even larger.