title: Head-to-tail square-shaped cyclic hydrogen bonds leading to dimeric aggregates: 1,8-dibenzoyl-2,7-dihydroxynaphthalene and a comparison with its analogous benzoylnaphthalene.
abstract: The title compound, C24H16O4, crystallized with two independent molecules in the asymmetric unit. Both carbonyl groups in these molecules form intramolecular O-H...O=C hydrogen bonds with neighbouring hydroxy groups, affording six-membered cyclic structures. In the crystal, dimeric aggregates arise from two intermolecular O-H···O=C hydrogen bonds between both independent molecules, forming head-to-tail square-shaped cyclic ···O···H···O···H··· hydrogen bonds. These dimeric aggregates are connected into layers in the bc plane by intermolecular (naphthalene)C-H...O=C interactions. On the other hand, the analogous compound bearing methoxy groups at the 2- and 7-positions of the naphthalene ring, namely 1,8-dibenzoyl-2,7-dimethoxynaphthalene [Nakaema et al. (2008). Acta Cryst. E64, o807], forms a three-dimensional molecular network via C-H···O=C and π-π interactions between the benzoyl groups. These results show that the intramolecular O-HvO=C hydrogen bonds in the title compound control the orientations of the benzoyl groups and thus promote the formation of the cyclic intermolecular O-H···O=C interactions involving the same donor and acceptor groups in pairs of molecules.
authors: Department of Organic and Polymer Materials Chemistry, Tokyo University of Agriculture & Technology (TUAT), Koganei, Tokyo 184-8588, Japan.
authors: Saki
authors: S
authors: Mohri
authors: Sayaka
authors: S
authors: Yoshiwaka
authors: Katsuhiro
authors: K
authors: Isozaki
authors: Noriyuki
authors: N
authors: Yonezawa
authors: Akiko
authors: A
authors: Okamoto
keywords: 1,8-dibenzoyl-2,7-dihydroxynaphthalene; O—H...O=C hydrogen bonds; crystal structure; cyclic hydrogen bonds