Noriyuki Yonezawa

Comparative structural analysis of 2,7-diethoxy-1,8-bis(4-phenoxybenzoyl)naphthalene and its homologues: orientation of the 4-phenoxybenzoyl groups at the 1- and 8-positions of the naphthalene ring.

The title molecule, C40H32O6, possesses crystallographically imposed twofold symmetry, with the central two C atoms of the naphthalene unit sited on the rotation axis. The two 4-phenoxybenzoyl groups in the molecule are twisted away from the attached naphthalene unit, with a torsion angle of 66.76 (15)° between the naphthalene unit and the carbonyl group (C-C-C=O), and are oriented in mutually opposing directions (anti orientation). There is an apparent difference in the conformations of the 4-phenoxybenzoyl groups at the 1- and 8-positions of the naphthalene ring between the title molecule and its methoxy-bearing homologue [Hijikata et al. (2010). Acta Cryst. E66, o2902-o2903]. Whilst the 4-phenoxybenzoyl groups in 2,7-diisopropoxy-1,8-bis(4-phenoxybenzoyl)naphthalene [Yoshiwaka et al. (2013). Acta Cryst. E69, o242] are situated in the same anti orientation as the title molecule, those of 2,7-dimethoxy-1,8-bis(4-phenoxybenzoyl)naphthalene are oriented in the same direction with respect to the naphthalene ring system, i.e. in a syn orientation.

(2,7-Dimethoxynaphthalen-1-yl)(4-methoxyphenyl)methanone

In the molecule of the title compound, C20H18O4, the dihedral angle between the naphthalene ring system and the benzene ring is 81.74 (5)°. An intermolecular C—H⋯O interaction is formed between an H atom at the 6-position of the naphthalene ring and the O atom of the methoxy group at the 7-position.