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oai:ojs.www.eurjchem.com:article/1572 2017-06-30T04:23:02Z eurjchem:ART driver

Crystal structure of 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl) naphthalene: Head-to-head fashioned molecular motif for accumulating weak non-classical hydrogen bonds Yokoyama, Takeshi Mido, Takahiro Takahara, Genta Ogata, Kazuki Chwojnowska, Elżbieta Yonezawa, Noriyuki Okamoto, Akiko Cooperative effect Crystal engineering Weak hydrogen bonds Noncovalent interactions Head-to-head orientation X-ray single crystal structure Title compound, 1-benzoyl-2,7-dimethoxy-8-(3,5-dimethylbenzoyl)naphthalene, an unsymmetrically substituted aromatic diketone compound having non-coplanarly accumulated aromatic rings structure, has been synthesized and its crystal structure has been determined by X-ray crystallography. The asymmetric unit of title compound contains two independent conformers. For each conformer, the two aroyl groups are non-coplanarly situated against the naphthalene ring plane and oriented in an opposite direction. The 3,5-dimethylbenzoyl group leans more than the non-substituted benzoyl group on the other peri-position of the naphthalene ring. The characteristics in the single molecular crystal structure of this unsymmetrical compound show unique relationship with two symmetrically substituted homologues, namely 1,8-dibenzoyl-2,7-dimethoxynaphthalene and 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl) naphthalene. Dihedral angles between 3,5-dimethylbenzene ring and naphthalene ring of 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene are larger than those between benzene ring and naphthalene ring of 1,8-dibenzoyl-2,7-dimethoxynaphthalene. Dihedral angle between 3,5-dimethylbenzoyl group and naphthalene ring in title compound is close to those of symmetrical homologue having two 3,5-dimethylbenzoyl groups. In the similar manner, dihedral angle between non-substituted benzoyl group and naphthalene ring in title compound is also close to those of symmetrical homologue bearing two non-substituted benzoyl groups. On the other hand, the crystal packing of title compound has rather similar feature with 2,7-dimethoxy-1,8-bis(3,5-dimethylbenzoyl)naphthalene. Two compounds have common crystalline molecular structural motif of head-to-head fashioned intermolecular interaction of 3,5-dimethylbenzoyl moieties. It is interpreted that the interactions between (sp3)C–H and π orbital preferentially govern the molecular packing motif. Molecular structure feature of title compound and the symmetrically 3,5-dimethylbenzoylated homologue strongly manifests that accumulation of weak non-classical hydrogen bonds play a crucial role in determination of the crystal packing rather than sole function of stronger non-classical hydrogen bond and π…π stacking. Atlanta Publishing House LLC 2017-06-30 info:eu-repo/semantics/article info:eu-repo/semantics/publishedVersion application/pdf https://www.eurjchem.com/index.php/eurjchem/article/view/1572 10.5155/eurjchem.8.2.188-194.1572 European Journal of Chemistry; Vol. 8 No. 2 (2017): June 2017; 188-194 2153-2257 2153-2249 eng https://www.eurjchem.com/index.php/eurjchem/article/view/1572/pdf_1572